Miscellaneous conditions

Chapter 1: Congenital heart disease & GUCH (Grown Up Congenital Heart disease)

Echocardiography in Congenital Heart Disease (CHD) and Grown Up Congenital Heart (GUCH) disease

Survival in congenital heart disease (CHD) has increased dramatically over the past few decades. This has resulted in an increased prevalence of congenital heart disease in the general population, such that most clinicians will regularly encounter patients with CHD. Approximately 95% of all incident cases of congenital heart disease reach adulthood (Mandalenakis et al). The largest leap in survival has been observed among cases with the most complex malformations. Indeed, even the most severe malformations have become routine practice. The treatment repertoire includes surgery, catheter interventions, and medical therapies. Adults with congenital heart disease are mostly managed in GUCH clinics (Grown Up Congenital Heart disease).

Prevalence of congenital heart disease (CHD)

Congenital heart disease (CHD) is the most common class of major congenital malformations. CHD occurs in approximately 1% of live births, and 10% of aborted fetuses, with no significant geographical variations. Roughly 25% of children with congenital heart disease require intervention during their first year of life (Triedman et al).

According to the European Society for Cardiology, 2800 adults per 1 million individuals have congenital heart defects, and half of them have moderate or complicated defects; the remaining third have mild defects (Baumgartner et al). Approximately 40,000 children are born with CHD annually in the United States (Triedman et al).

The prevalence of congenital heart disease will increase in parallel with the prolongation of survival.

Neonatal screening with pulse oxymetry

The majority of all congenital heart defects are detected early in infancy or childhood. For obvious reasons, more complex defects are typically diagnosed earlier. Defects resulting in reduced oxygen saturation are generally detected with neonatal pulse oximetry (POX) screening, which is routine in all Western countries. According to a Cochrane review, for every 10,000 apparently healthy newborn infants, around six will have critical CHD, and the pulse oximetry test will correctly identify five of these with critical CHD (Plana et al). Minor defects can go unnoticed for many years. Occasionally, major defects may go unnoticed until adulthood.

Echocardiography in CHD

Echocardiography is performed in all patients with suspected CHD. Echocardiography provides detailed morphological and functional information. The vast majority of cases can be characterized by echocardiography.

In comparison with adult subjects, the echocardiographic evaluation in pediatric patients requires a different approach, with more emphasis on the heart position in the thorax, the atrial situs viscerum, the vein-atrial and the atrio-ventricular connections, the relationship between the ventricles, the ventriculo-arterial connection and the relationship of the great arteries (segmental analysis).

Ventricular function is evaluated using ejection fraction, fractional shortening, stroke volume, and myocardial thickness. Strain imaging is also used routinely to visualize regional myocardial function and mechanics. Loading conditions and heart rate may affect left ventricular function.

Transesophageal echocardiography (TEE) is superior to transthoracic echocardiography (TTE), although the latter is the most frequently used method.

Many patients require evaluation with additional modalities, e.g cardiac magnetic resonance imaging (MRI), cardiac computerized tomography (CT), ergospirometry (exercise stress testing), and cardiac catheterization.

Principles of management of congenital heart disease and GUCH

Complex malformations often require intervention (surgical or catheter-based intervention). In addition to the malformation, these subjects frequently develop associated complications, which may require specific treatments. Such complications include heart failure, ventricular arrhythmias (eg, ventricular tachycardia), supraventricular arrhythmias (eg, atrial fibrillation), pulmonary hypertension, arterial (systemic) hypertension, thromboembolism and endocarditis. Management of these complications follows conventional guidelines and principles. Unfortunately, randomized trials have not been conducted in these subjects, which explains why most recommendations are based on extrapolation of studies conducted in other patient populations. For example, management of heart failure in CHD follows the same principles as management of HFREF (heart failure with reduced ejection fraction).

Arrhythmias are also common among people with congenital heart disease, even after correction of the defect. Because individuals with GUCH often have impaired cardiac function, even mild arrhythmias can cause decompensation or hemodynamic deterioration.

Patients with GUCH who have suffered sudden syncope should be carefully evaluated since they are at increased risk of cardiac arrest and sudden death. The malformations associated with the greatest risk are tetralogy of Fallot, transposition of the great arteries (TGA), CCTGA (Congenitally corrected transposition of the great arteries), congenital aortic stenosis and single ventricle (UVH, univentricular heart).

ASD (Atrial Septal Defect)

Atrial septal defect (ASD) allows blood to flow from the left atrium to the right atrium. Left atrial pressure is greater than right atrial pressure, which explains why blood flows from left to right. The shunting of blood from left to right results in volume overload on the right side, and ultimately dilation of the right atrium and right ventricle. Conditions leading to increased pressure on the left side (hypertension, cardiomyopathy, aortic regurgitation, aortic stenosis, mitral regurgitation, mitral stenosis) may further increase the shunting from left to right.

Volume overload in the right ventricle leads to bulging of the septum into the left ventricle. This gives the left ventricle a D-shaped appearance in PSAX (parasternal short-axis view). As a result of volume overload, right ventricular stroke volume increases, which leads to increased flow through the pulmonary circulation. Over time, PVR (pulmonary vascular resistance) and pulmonary artery (PA) pressure tend to increase. The increase in PVR and PA pressure may result in the pressure on the right side ultimately exceeding the pressure on the left side, which leads to blood being shunted from right to left. The shunting of deoxygenated blood into the left ventricle results in the development of cyanosis. This condition is referred to as Eisenmenger’s syndrome.

Estimation of shunt size in ASD

The size of the shunt is calculated by estimating blood flow through the pulmonary and systemic circulation. This is achieved by comparing right and left ventricular stroke volumes. The right ventricular stroke volume is calculated with the pulsed wave doppler placed in the pulmonary trunk (truncus pulmonalis) or RVOT. Left ventricular stroke volume is calculated with the pulsed wave doppler placed in LVOT.

Left ventricular stroke volume (SV):

SVLVOT = areaLVOT · VTILVOT

Right ventricular stroke volume (SV):

SVRVOT = areaRVOT · VTIRVOT

The shunt size is calculated by the following formula:

SVRVOT/SVLVOT

If the stroke volume is 120 ml and 40 ml, respectively, then the shunt size is calculated as:

120/40 = 3

This is expressed as a 3:1 shunt (“3 to 1 shunt”). The calculation is uncertain in pulmonic regurgitation and aortic regurgitation since these conditions render the calculation of stroke volume uncertain.

Types of atrial septal defect (ASD)

Figure 1. Types of ASD (atrial septal defects).

Atrial septal defect (ASD) is – second to bicuspid aortic valve – the most common congenital heart defect. ASDs are subdivided into four types (Figure 1):

Secundum defect (ostium secundum defect)Primum defect (ostium primum defect)Sinus venosus defectCoronary sinus defect (sinus coronarius defect)

Secundum defect

Approximately 80% of all atrial septal defects are secundum defects, which are located in the fossa ovalis and its surroundings. Secundum defects include defects of the foramen ovale. Multiple secundum defects may exist. Transthoracic echocardiography (TTE) can visualize major ASDs, but transesophageal echocardiography (TEE) is required in most cases.

Primum defect

Primum defects represent 15% of all ASDs. These defects are located in lower parts of the atrial septum, near the atrioventricular plane. Primum defects are often accompanied by mitral or tricuspid valve defects (typically a cleft in the anterior leaflet of the mitral valve, which can lead to mitral regurgitation). TEE is superior to TTE for visualizing primum defects.

Sinus venosus defect

Sinus venosus defects affect the superior vena cava (5%) or the inferior vena cava (< 1%). These defects may lead to pulmonary veins emptying oxygenated blood into the right atrium or into the superior/inferior vena cava. TEE is required to detect this defect.

Coronary sinus defect

Coronary sinus defect (< 1%) is rare and located in the coronary sinus ostium in the right atrium. In these cases, the coronary sinus lacks a roof (“unroofed coronary sinus”), which results in a communication between the atria.

Prognosis in ASD

ASD is typically asymptomatic until adulthood. After 40 years of age, patients tend to develop signs of right heart failure. Supraventricular arrhythmias (atrial fibrillation, atrial flutter) are common. Severe pulmonary hypertension affects < 5%. Paradoxical embolisms occur but are likely to be less common than emboli arising in the left atrial appendage during rounds of atrial fibrillation.

Right ventricular load (volume load) is the main finding on echocardiography.

Ventricular septal defect (VSD)

Ventricular septal defect (VSD) is common and may be detected throughout the life course. The larger the defect, the greater the hemodynamic impact, and the earlier the diagnosis. Most defects are diagnosed in childhood or adolescence. Defects detected in adulthood are generally smaller and rarely cause hemodynamic effects. Most VSDs diagnosed during infancy close spontaneously during the first year of life.

VSD can exist in isolation or in combination with more complex heart defects (e.g tetralogy of Fallot, transposition of the great arteries, etc).

VSD leads to volume load on the left ventricle, despite the fact that blood is shunted from the left to the right ventricle. It is presumed that this is due to the fact that the right ventricle receives shunted blood during systole and manages to eject it to the lungs, and further to the left atrium and ventricle. Therefore, VSD leads to left ventricular overload and dilatation. As with ASD, perfusion through the pulmonary circulation increases, which may lead to pulmonary hypertension. With continuous wave doppler, the flow through a VSD can be used to calculate the pressure gradient between the ventricles.

Based on the location of the VSD, the following types are defined (Figure 2):

Membranous VSD – The most common (80%) type of VSD. It affects the membranous part of the interventricular septum. These defects are best seen in parasternal views; notably in SAX at 10 o’clock. Spontaneous closure is common. In case of spontaneous closure, an aneurysm may develop. Coexisting aortic regurgitation is common.Muscular VSD (15%) – Muscular VSDs can exist anywhere in the muscular segments of the septum. Multiple defects may exist. Spontaneous closure is very common. Muscular VSD may be seen in apical four-chamber view (A4C) and short-axis view (SAX).Outlet VSD (5%) – This VSD is seen in SAX view and is localized at 2 o’clock, below the wall of the aortic valve and pulmonary valve. The support of the aortic valve is impaired, with a risk of aortic regurgitation. Spontaneous closure is less common.Inlet VSD (< 1%) – Inflow VSD is localized in the inflow of the septum. It is typical in Down syndrome and the defect is often large. Spontaneous closure is less common.

Figure 2. Types of ventricular septal defects (VSD).

Figure 3. Membranous VSD.

Figure 4. Outlet VSD.

Figure 5. Muscular VSD.

Gerbode defect

Since the tricuspid valve is more apical than the mitral valve, a VSD can cause blood shunting from the left ventricle to the right atrium, as shown in Figure 6. This type of defect is called Gerbode defect.

Figure 6. Gerbode defect.

Persisting ductus arteriosus (PDA)

Ductus arteriosus is the connection, during fetal life, between the pulmonary artery and the descending aorta. Persisting ductus arteriosus (PDA) implies that this connection fails to close after birth. PDA is rare in adulthood. The defect leads to volume load on the left ventricle and the risk of developing pulmonary hypertension. PDA is best seen with color Doppler in suprasternal view or short-axis view (SAX). The image should focus on the pulmonary trunk and bifurcation. Blood flow through PDA goes from the aorta to the pulmonary trunk.

Figure 7. Persisting ductus arteriosus (PDA).

Coarctatio Aortae (CA)

Coarctatio aortae implies that there is a narrowing along the aorta and this narrowing is most often located along the descending aorta, which is why it can be visualized from the suprasternal view. Color Doppler reveals turbulent flow and continuous wave Doppler reveals increased velocities.

Figure 8. Coarctatio Aortae (CA)

Ebstein’s Anomaly

Normally, the tricuspid valve is more apically located than the mitral valve. Ebstein’s anomaly implies that the tricuspid valve sits lower than normal (Figure 9). The criterion for Epstein’s anomaly is that the tricuspid valve plane is located >10 mm apical about the mitral valve plane. The tricuspid valve may shift right down the apex of the right ventricle and, generally, there is a more or less pronounced tricuspid regurgitation.

Figure 9. Ebstein’s anomaly.

Congenital corrected transposition of the great arteries (CCTGA)

Transposition of the Great Artiles (TGA) implies that two or more of the large vessels have switched locations. Most often, the aorta and pulmonary artery have switched positions, which results in the left ventricle pumping blood into the lungs, and the right ventricle pumping blood to the systemic circulation. The blood on the left side circulates between the lungs and the left heart. The blood on the right side circulates between the systemic circulation and the right heart. This means that blood flowing through the systemic circulation is not oxygenated, which leads to fatal hypoxia. The only chance of survival is if there is a shunt that allows shunting of blood between the circulations. The open ductus arteriosus, ASD and VSD are in these cases life-saving. Today, these malformations are detected quickly and they can be corrected surgically.

Correction of transposition implies reconnecting the large vessels so that they conduct blood from the right ventricle. The right ventricle will then function as the left ventricle and vice versa.

References

Survivorship in Children and Young Adults With Congenital Heart Disease in Sweden. Mandalenakis Z et al. JAMA Intern Med. 2017;177(2):224-230.Trends in Congenital Heart Disease The Next Decade. Triedman et al. Circulation. 2016;133:2716–2733Plana et al. Pulse oximetry for diagnosis of critical congenital heart defects. Cochrane Collaboration.

---

Chapter 2: Cardiac thromboembolism: cardiac sources of embolism

Cardiac thromboembolism

Thromboembolism is a leading cause of death worldwide (1). Emboli originating in the atria, left atrial appendage (LAA), ventricles, valves, and proximal aorta can cause stroke, TIA (transient ischemic attack), coronary artery occlusion, and peripheral embolization. Stroke is the third leading cause of death in Western countries, and ultrasound studies are now performed in the majority of patients with stroke or TIA. The purpose of performing an ultrasound is to scrutinize potential cardiac sources of emboli and to evaluate the carotid and cerebral arteries. Ultrasound may reveal atherosclerotic plaques, thrombi, occlusions, and dissections.

Stroke is subdivided into hemorrhagic stroke (13% of all cases) and ischemic stroke (87% of all cases). The terms hemorrhagic stroke and intracerebral hemorrhage are used interchangeably. Hemorrhagic stroke implies bleeding directly into the brain parenchyma. The most common underlying etiology is hypertension. Ischemic stroke occurs when a cerebral artery is occluded due to local atherothrombosis or occlusion due to embolization. Approximately 30% of all ischemic strokes are caused by cardiac embolism. This figure does not include paradoxical embolism (discussed below) and emboli from the proximal aorta.

Stroke and TIA (Transient Ischemic Attack)

Ischemic stroke constitutes 87% of all stroke cases and is further divided into the following categories:

Lacunar stroke or lacunar infarct (occlusion of small penetrating arteries): This is the most common type of ischaemic stroke, resulting from the occlusion of small penetrating arteries that provide blood to deep structures. Lacunar stroke results in five classical lacunar syndromes, namely:(1) pure motor stroke/hemiparesis(2) ataxic hemiparesis(3) dysarthria(4) pure sensory stroke(5) mixed sensorimotor stroke.Cardioembolic strokeThromboembolism associated with cerebral atherosclerosis.Cryptogenic stroke: These cases have no known mechanism.Paradoxical embolism: Paradoxical embolism occurs when thromboembolic material is transported from the venous circulation to the arterial circulation, e.g via a persistent foramen ovale (PFO), which enables blood flow from the right to the left atrium.

Echocardiography is of importance for cardioembolic stroke, cryptogenic stroke, and for emboli arising in the proximal aorta.

Cardioembolism is the cause of 30% of all ischemic strokes.

Embolic material

Cardiac emboli may consist of the following materials:

Coagulated bloodTumor tissueFragments from vegetations (septic or aseptic vegetations)Fragments of calcificationsAtherosclerotic debris

Embolic potential

Numerous conditions can give rise to emboli in the heart. These conditions may be ranked according to their embolic potential. Conditions with high embolic potential entail a high risk of embolism and vice versa. Table 1 lists these conditions.

TABLE 1. SOURCES OF CARDIAC EMBOLI AND EMBOLIC POTENTIAL
HIGH EMBOLIC POTENTIAL
Atrial arrhythmias — especially atrial fibrillation and atrial flutter.
Ischemic heart disease – Both acute and chronic ischemic heart disease (including complications) can cause embolisms.
Left ventricular aneurysm with thrombus
Cardiomyopathies
Valve prosthesis
Devices (pacemaker, ICD CRT)
Endocarditis
Cardiac tumors
Atherosclerosis of the aorta
LOW EMBOLIC POTENTIAL
SEP (Spontaneous Echocardiographic Potential)
Left ventricular aneurysm without thrombus
Prolapse of mitral valve
Aortic stenosis with calcification
Mitral disease with calcification
Fibrin strands
Giant Lambls excrescences
Septum Defects — PFO, ASA, ASD

Echocardiography for the investigation of cardiac embolic sources

The aim of echocardiography is to investigate if there are sources of emboli in the heart and, if the patient has suffered a stroke/TIA, to assess whether the embolic source is the most likely cause of the event. Echocardiographic assessment of cardiac embolic sources requires careful imaging and knowledge of differential diagnoses. Echocardiography is typically done using two-dimensional (2D) ultrasound, but 3D ultrasound is becoming increasingly capable in this context. In case of suspicion of a thrombus in the ventricular cavity, contrast can be used to improve the image resolution.

Transthoracic echocardiography (TTE) most often gives an adequate picture of the ventricles. However, TTE does not provide enough good resolution of the atria, auricle, atrial septum and aorta. Where the embolic source is suspected to be located in any of these premises, the TEE (transesophageal echocardiography) shall be selected. With TEE, a significantly better picture of the atria and aorta is obtained. In general, TEE has higher sensitivity and specificity for all embolic sources with the exception of left ventricle apical thrombi, which are best seen with TTE.

TEE should be preferred in case of suspicion of posteriorly located embolus (left atrium, SEC [spontaneous echo contrast], aortic plaques, valve prostheses, vegetations, defects of the interatrial septum, tumors). TTE is preferred in case of suspicion of a thrombus in the left ventricle.

Thromboembolism from the left atrial appendage

The left atrium and left atrial appendage are the most common sources of cardiac emboli. Thrombus formation is strongly associated with atrial arrhythmias (atrial fibrillation, atrial flutter) and the vast majority of thrombi arise in the left atrial appendage. It is believed that slow blood flow in the appendage results in thrombosis (stasis promotes coagulation). Approximately 75% of all cardiac emboli originate in the left atrial appendage and this site should be the primary suspect in patients with atrial fibrillation (2).

Left atrial appendage morphology

It has been proposed that there are at least four different morphological variants of the left atrial appendage. Di Biase et al studied different anatomical variants, their prevalence, and how they correlated with the risk of stroke and TIA (3, 4). They report that 30% were Cactus shaped, 48% were chicken wing-shaped, 19% windsock shaped and 3% were cauliflower-shaped. Chicken wing morphology was associated with the lowest risk of stroke/TIA (79% less likely to have a stroke/TIA history).

Atrial fibrillation and cardioembolism

Although it is clear that 75% of all cardioembolism originate in the left atrial appendage and most cases occur during episodes of atrial fibrillation, the exact mechanisms of the thrombosis remain largely unknown. According to Virchow’s triad, there are three factors that cause thrombosis:

Hemodynamic changes (stasis, turbulence)Endothelial damage or dysfunction – Damaged endothelium exposes collagen to the blood flow, which results in a reaction between collagen and von Willebrand factor and, consequently, platelet activation.Hypercoagulability – any procoagulant state, condition or substance

Stasis of flow frequently occurs in the left atrium and left atrial appendage. A mild form of stasis is SEC (spontaneous echo contrast), which is typically visualized with TEE and less often with TTE. SEC occurs when the flow of blood in the atrium is slow, causing erythrocytes to stick to each other and form rouleaux aggregates. SEC appears as smoke on the 2D image and is very common during episodes of atrial fibrillation.

Atrial fibrillation results in a reduction of effective atrial contractile function, which is the main explanation for the stasis of flow during fibrillation. Stasis may, however, also occur during sinus rhythm in the setting of left atrial enlargement, which may be secondary to valvular heart disease (e.g mitral valve stenosis).

If blood flow decreases further, SEC transforms into sludge, which implies that the smoke is very dense.

SEC is defined as smoke in the ultrasound image. Sludge is defined as dense smoke. A thrombus is a distinct mass.

Embolism and electrical cardioversion

Patients with permanent atrial fibrillation should not undergo electrical cardioversion since the fibrillation relapses quickly. Electrical cardioversion may be attempted in patients with paroxysmal atrial fibrillation. Any cardioversion carries a risk of embolization. There are two possible mechanisms underlying embolic events after cardioversion:

Embolization occurs when sinus rhythm is restored and atrial contractility returns; the contractions lead to detachment of a previously formed thrombus.Cardioversion may result in atrial stunning, which is evident from increased SEC after cardioversion, which results in blood stasis and thrombus formation (Black et al, Grimm et al).

Current guidelines (AHA, ESC 2019-2020) suggest that arrhythmia duration and CHADS-VASC score are the main predictors of cardioembolism after cardioversion. With regard to arrhythmia duration, it is believed that the longer atrial fibrillation has persisted, the greater the probability of thrombi forming in the atria.

Most guidelines have recommended that if the duration of the arrhythmia is <48 hours, then the patient can be cardioverted subacutely (i.e at the time of initiating anticoagulation with NOAC or warfarin). If an arrhythmia has persisted >48 hours, anticoagulation should be initiated and continued for 3-4 weeks before cardioversion is attempted. The purpose of 3-4 weeks of anticoagulation therapy is to dissolve any thrombi in the atrium before cardioversion is attempted. If the duration of the arrhythmia is uncertain, or if cardioversion must be performed early, TEE (transesophageal echocardiography) can be used to examine the presence of thrombi in the atrium and left atrial appendage (Airaxsinen et al, Alastair et al, Kirchoff, etc.). It is believed that a negative TEE examination rules out the existence of thrombi in the left atrium and left atrial appendage, such that cardioversion can be performed regardless of the duration of the arrhythmia.

Note that the 48-hour cut-off is not based on robust clinical data. The longer the duration of the arrhythmia, the greater the risk of cardioembolism.

Echocardiographic assessment of the left atrial appendage

Assessment of the left atrium and the appendage should determine whether the atrium is enlarged. This can be done with measurement of atrial diameter (anteroposterior diameter) or estimation of atrial volume (can be adjusted for body surface area [BSA]). TEE should be the preferred method for these measurements; TEE has significantly higher sensitivity and specificity for atrial thrombi, as compared to TTE. As mentioned previously, TEE can be used to rule out atrial thrombi before cardioversion in patients with atrial fibrillation/flutter. In selected cases, the study may be augmented with contrast or three-dimensional (3D) TEE.

Thromboembolism from the left ventricle

Acute Myocardial Infarction (AMI)

Virtually all myocardial infarctions affect the left ventricle, and the terms anterior, lateral, septal and inferior myocardial infarction refers to the four walls of the left ventricle. The right ventricle is spared in the majority of cases. Right ventricular infarction occurs if the occlusion is located in the proximal segment of the right coronary artery, such that r. marginalis dx (right marginal branch) is affected.

Walls of the left ventricle and coronary artery supply.

Localization of coronary arteries, myocardium and ECG leads

Recommended chapter: Localization of acute myocardial infarction using ECG.

Contractility ceases permanently in the infarcted myocardium. Depending on the extent of the infarction, the affected wall will display varying degrees of wall motion abnormalities. The velocity of blood flow over the infarcted area will be reduced and, along with the tissue damage and potentially also pro-thrombogenic state, will serve as a nidus for thrombus formation. Thrombi typically form within 24 hours after the onset of myocardial infarction; 90% of all thrombi form within 10 days. The risk of thrombus formation in the left ventricle is especially great in the setting of left ventricular aneurysm or enlargement. Up to 50% of all cases of left ventricular aneurysm display thrombi. Among patients with acute coronary syndromes, 5 -15% have left ventricular thrombi (Chiarella et al, Solheim et al, Weinsaft et al).

Risk factors for left ventricular thrombosis:

Left ventricular dilatation.Anterior AMI.Large AMI.Reduced ejection fraction (EF).SEC (spontaneous echo contrast) in the ventricular cavity.

Cardiomyopathy

All patients with cardiomyopathy have an increased risk of left ventricular thrombosis. The risk is greatest if the left ventricle is dilated.

Types of thrombi in the left ventricle

Mural thrombi: A mural thrombus is a flat mass located along the myocardium. These thrombi display the lowest risk of embolization. Protruding thrombi: A protruding thrombus protrudes into the ventricular cavity.Mobile thrombi: A mobile thrombus protrudes into the ventricular cavity and swings back and forth. These thrombi display the greatest risk of embolization.

Echocardiography for visualization of thrombi in the left ventricle

Transthoracic echocardiography (TTE) is excellent for detecting thrombi in the left ventricle. TTE has 95% sensitivity and 85-90% specificity. The thrombus should be visualized in at least two different views. It appears as a mass attached to the endocardial surface, with or without a protruding part. The myocardium typically displays wall motion abnormalities.

Cardioembolism in valvular heart disease

Native and prosthetic valves may cause embolic events through thrombus formation or detachment of vegetations (endocarditis) or calcifications.

Septic endocarditis

Endocarditis is a common cause of cardioembolism. Microembolism may occur even in the absence of visible vegetations. The larger the vegetations, the larger the dispatched fragments (Thuny et al).

Aseptic endocarditis

Libman-Sacks endocarditis (verrucous endocarditis)

Libman-Sacks endocarditis appears similar to bacterial endocarditis on echocardiography. However, this endocarditis is aseptic (nonbacterial) and the vegetation consists of immune cells, hematoxyl bodies, coagulation factors and thrombocytes. Libman-Sacks endocarditis does not result in valve destruction and is, therefore, less acute than bacterial endocarditis. Most patients with Libman-Sacks endocarditis display mild symptoms, which is explained by the small hemodynamic effects of this endocarditis. The vast majority of patients who develop Libman-Sacks endocarditis have SLE (systemic lupus erythematosus). Antiphospholipid syndrome is also associated with Libman-Sacks endocarditis.

This endocarditis typically affects the mitral and/or aortic valve. It is difficult to distinguish Libman-Sacks endocarditis from bacterial endocarditis. Moreover, these nonbacterial vegetations may become colonized by bacteria, and thus progress to bacterial endocarditis.

Embolization is rare in Libman-Sacks endocarditis.

Marantic endocarditis

The term marantic is derived from the disease marasmus, which is a condition caused by severe malnutrition (primarily due to protein deficiency). Marasmus has become rare, even in low-income countries. In the Western world, marantic endocarditis is a paraneoplastic manifestation of carcinomas; the most common underlying cancers are lung cancer, pancreatic cancer, gastric (ventricular) cancer. These cancers result in hypercoagulable blood, which leads to the accumulation of fibrin and thrombocytes on the valves.

Strands & Lambl’s excrescences

Strands and Lambl’s excrescences are most likely common in the population. Some studies suggest that up to 50% of all individuals have these structures (Roldan et al), which are fibrous strands, typically occurring at the coaptation lines of the mitral valve or aortic valve. The strands are composed of collagen, elastin, and an outer endothelial layer. They are usually 2 mm in diameter and 3 to 10 mm long. Strands attached to the mitral valve usually appear in the left atrium, and those attached to the aortic valve typically appear in the LVOT. Strands and Lambl’s excrescences are rare on the pulmonic valve and tricuspid valve.

Transesophageal echocardiography (TEE) is the gold standard for diagnosing strands and Lambl’s excrescences, although the method does not allow distinguishing strands from excrescences.

Strands and Lambl’s excrescences rarely cause thromboembolism.

Calcification of the mitral annulus

The mitral annulus may become calcified. A calcified mitral annulus appears as a thick and irregular annulus with high echogenicity on echocardiography. Calcifications are most pronounced on the segment attaching the posterior leaflet. Calcifications are best seen with transthoracic echocardiography (TTE).

Calcifications are associated with an increased risk of cardiac thromboembolism, which is explained by the following mechanisms:

Calcifications predispose to bacterial endocarditis. Calcifications are associated with atherosclerosis in coronary, cerebral and other arteries. Atherosclerotic plaques may rupture and thus lead to atherothrombosis and artery occlusion.Calcifications may serve as a nidus for thrombus formation, and thrombotic fragments may detach and embolize.Calcifications are associated with atrial dilatation (enlargement) and, consequently, atrial fibrillation, which in turn increases the risk of thromboembolism.

Prosthetic valves

Mechanical prosthetic valves are associated with a very high risk of thromboembolism, which is why anticoagulation is fundamental for these individuals. The annual incidence of thrombosis is 1.0-2.0% among individuals with mechanical valves, with the highest risk seen with mechanical tricuspid or mitral valves. In the majority of these cases, thrombus formation occurs during episodes of sub-therapeutic anticoagulation. The incidence of thrombosis is approximately 0.5-1.0% for biological valves.

It should be noted that thromboembolism on pulmonic and tricuspid valve causes pulmonary embolism, while thromboembolism on the left side causes embolism to the systemic circulation.

Cardiac tumors

Primary cardiac tumors originate in cardiac tissue. These tumors are mostly benign but present a high risk of thromboembolism. Myxoma and papillary fibroelastoma (PFE) are the most prevalent cardiac tumors. Such tumors may cause thromboembolism if tumor mass detaches or if thrombi forms on it.

Myxoma

Approximately 75% of all myxomas occur in the left atrium and these tumors typically have a stalk attached to the fossa ovalis. Approximately 30% of all myxomas result in thromboembolism.

Papillary fibroelastoma (PFE)

Papillary fibroelastoma (PFE) is associated with a high risk of thromboembolism. Roughly 80% of all papillary fibroelastomas develop on the valves, mostly the aortic valve and mitral valve. PFEs on the aortic valve are typically visible in the aortic root and those on the mitral valve are mostly seen in the left ventricular cavity.

Malignant cardiac tumors

Sarcoma is the most common malignant cardiac tumor. These tumors are most often localized on the right side and confer a high risk of pulmonary embolism.

Embolism from the aorta

Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) can visualize large portions of the aorta and elucidate sources of thromboembolism. The vast majority of all emboli from the aorta originate in atherosclerotic plaques. Such plaques (atheromas) are located in the innermost layer of the wall, i.e the intima (tunica intima). The development of plaques begins during adolescence and is accelerated by risk factors such as diabetes (type 1, type 2), insulin resistance, hypertension, smoking, hypercholesterolemia (dyslipidemia) and genetic variants. LDL cholesterol has a fundamental role in the development of atherosclerosis (Libby et al, Ference et al.). The atherosclerotic plaque consists of lipids, immune cells (macrophages, T-cells, B cells) and cellular debris. Plaques are vulnerable, meaning that they can rupture or ulcerate. Plaque burden (the amount of atherosclerosis) typically increases in the direction from the proximal to the distal aorta. The risk of embolism correlates strongly with plaque burden. The following mechanisms lead to thromboembolism:

Thrombosis – rupture or ulceration of an atherosclerotic plaque leads to thrombus formation and embolism.Cholesterol embolism – some plaques have very high cholesterol concentration which leads to the formation of crystals. Cholesterol crystals can detach and thus cause embolism.

Aortic thrombosis may result in large emboli that occlude large arteries. Stroke, TIA, renal infarctions, intestinal ischemia and limb ischemia are common in aortic thrombosis.

Cholesterol embolism results in the embolization of small crystals which leads to occlusion of distal (smaller) arteries. Multiple emboli may occur simultaneously. Common complications are renal failure, minor cerebral infarcts, mild limb ischemia, etc.

Transthoracic echocardiography (TTE) allows for visualization of the aortic valve and the ascending aorta. This is insufficient to evaluate plaque burden and the existence of aortic thrombi. Transesophageal echocardiography (TEE) is necessary to visualize the ascending aorta, aortic arch and descending aortic. TEE also provides a greater resolution of the aortic root. However, TEE does not allow for visualization of the aortic segment just proximal to a. brachiocephalica (brachiocephalic artery), which is due to the fact that this segment is obscured by the right bronchus and trachea. TEE usually allows for visualizing the aorta down to a. mesenterica superior (superior mesenteric artery). MRI or CT may occasionally be necessary to obtain satisfactory images.

Paradoxical embolism

Paradoxical embolization implies that an embolus in the venous system ends up in the arterial system and causes an occlusion on the artery side. This can occur if there are communications between the right and left halve of the heart. Examples of such communications are:

PFO (Homma et al)ASD

PFO (Persisting foramen ovale)

The septum of the atria is formed by two structures, septum primum and septum secundum . During fetal life, the septum primum and septum secundum are separated, giving rise to a channel, which serves as a wedge valve, between the atria; this channel is the foramen ovale. During fetal life, the foramen ovale is vital for the oxygen-rich blood from the placenta to pass from the inferior vena cava to the right atrium and directly to the left atrium. At birth, the foramen ovale and septum are closed, and the second grow together. The closure is explained by the fact that the pressure on the left side rises dramatically after birth, as a result of which the wedge valve can not be opened, and then a gradual sealing of the septum primum and secundum occurs. However, the closure becomes incomplete in 25% and there remains a window between the right and left atria. This window is called the persist foramen ovale (PFO). Since PFO has a prevalence of 25%, it can be seen as a normal variant. PFO is often accompanied by aneurysm of the septum primum. The opening itself exhibits great variety. Some PFO are very large while others are small tunnels.

PFO has no hemodynamic significance, but communication can lead to embolism in the right atrium entering the left atrium. Thus, embolisms formed in the veins (for example, in the legs) can pass from the right to the left atrium and provoke occlusions in the systemic circulation (on the side of the artery). This is called paradoxical embolization.

In situations of increased pressure on the right side, individuals with PFO exhibit shunting, which implies that blood flows from the right to the left atrium. This implies that in pulmonary hypertension or Valsalva maneuver, for example, a flow from right to left atrium is seen.

ASA (Atrial Septal Aneurysm)

ASA implies that the area corresponding to the fossa ovalis protrudes from the centre line. The aneurysm can be fixed or undulating. ASA is assumed to increase the risk of paradoxical embolization. Potentially large aneurysms can actually be the breeding ground for thrombosis because the blood stands still in the aneurysm.

Cryptogenic stroke

Cryptogenic stroke implies that one can not establish the cause of the stroke. In cryptogenic stroke, paradoxical embolization is a common suspicion. PFO is more common among people with cryptogenic stroke. Up to 40% of patients with cryptogenic stroke have PFO, which makes one inclined to explain stroke with paradoxical embolization. However, it is often difficult to establish with certainty that this is the cause.

Pulmonary embolism (PE)

Pulmonary embolism is the third most common cardiovascular cause of death, after acute myocardial infarction and stroke. Approximately 90-95% of all pulmonary emboli originate in the veins, particularly in the legs. Other causes of pulmonary embolism are endocarditis, tumor-associated thrombosis, or thrombosis on electrodes. Mortality in pulmonary embolism is 10%, which is significantly higher than mortality in STEMI (6-7%) and NSTEMI (5%). The mechanism of death in pulmonary embolism is circulatory collapse as a result of an embolus preventing blood flow through the pulmonary circulation.

Pulmonary embolism is typically diagnosed with CT. Echocardiography can be used for risk stratification. On echocardiography, the following signs of pulmonary embolism should be recognized:

Presence of thrombi in the inferior vena cava, hepatic veins, right heart. Right ventricular strain (RV strain): Echocardiographic signs of right ventricular strain are dilatation and dysfunction of the right ventricle. Dilatation is defined as the right ventricle being at least as large as the left ventricle. Paradoxical septal movement, which implies that the septum bulges into the left ventricle. Dilated proximal pulmonary arteries. Elevated pressure in the right ventricle. Abnormal tricuspid regurgitation (TI). Elevated right atrial pressure, which is seen as dilated inferior vena cava, without respiratory collapse.McConnell’s sign: preserved apical contractility in the right ventricle, but impaired basal and mid-ventricular contractility.

No ultrasound method can be used to rule out pulmonary embolism.

Classification of pulmonary embolism

Massive pulmonary embolism: pulmonary embolism with hypotension.Submassive pulmonary embolism: pulmonary embolism without hypotension but with signs of RV strain or elevated cardiac troponins.Low-risk pulmonary embolism: none of the above.

Dilatation of the right ventricle is also observed in the following conditions:

COPD (chronic obstructive pulmonary disease). Cor pulmonale (asthma) Pulmonary hypertension. Sleep apnea. Right heart failure. Right ventricular myocardial infarction.

References

1. Global, regional, and national age-sex-specific mortality for 282 causes of death in 195 countries and territories, 1980–2017: a systematic analysis for the Global Burden of Disease Study 2017. GBD 2017 Causes of Death Collaborators

2. Saric et al: Guidelines for the Use of Echocardiography in the Evaluation of a Cardiac Source of Embolism. Journal of the American Society of Echocardiography.

3. Di Biase Thrombogenic and Arrhythmogenic Roles of the Left Atrial Appendage in Atrial Fibrillation Clinical Implications. Circulation 2018

4. Di Biase: Does the Left Atrial Appendage Morphology Correlate With the Risk of Stroke in Patients With Atrial Fibrillation? Results From a Multicenter Study. JACC 2012.

---

Chapter 3: Endocarditis: definitions, causes, diagnosis, echocardiography & treatment

This chapter is available 2 days after the completion of the previous chapter.

Endocarditis

Endocarditis implies that a bacterial infection engages the heart valves and this is a serious condition. The focus of infection on the flap is called vegetation. As a rule, some kind of damage to native (own) valves is required to become vulnerable and contaminated by bacteria . Infections are difficult to heal because the heart valves are not vascularized and therefore it is difficult for the immune system to reach the bacteria.

Endocarditis can lead to the destruction of the valvular apparatus, as well as to embolization in the systemic circulation. The complications can be fatal. Approximately 500 Swedes are affected annually by endocarditis and the median age of 70 years at the onset of the disease. Approximately 12% die within 30 days, compared to the 30-day mortality of STEMI (ST segment elevation infarction) , which is about 6%.

Previously, alpha-streptococcus was the most common agent. These streptococci most often originate from the oral cavity and affect heart valves that have some kind of damage, change or degeneration. Endocarditis with alpha-streptococcus is most often subacute and can develop gradually over several days to weeks. More acute endocarditis is often caused by staphylococcus auerus. This usually affects drug users (intravenous addiction), elderly patients with altered valves, patients with valve prostheses or other cardiac devices (pacemaker, CRT, ICD). In addition to staphylococcus aureus , hemolytic streptococci and pneumococci cause acute endocarditis. Other microorganisms, generally, cause subacute endocarditis.

Endocarditis can affect native (own) valves and valve prostheses. As always, foreign materials pose a high risk of infection. Approximately 20% of all endocarditis affect people with valve prostheses and among other cases 18% show significant valvular disease.

Table 1. Etiologies in acute endocarditis.

Table 2. Etiologies in subacute endocarditis.

Echocardiography in endocarditis

In 1973, it was the first time to describe how echocardiography (M-mode) can be used to diagnose endocarditis. With 2D and later 3D ultrasound, the technology has been greatly refined. Similarly, the development of transesophageal echocardiography (TEE) has been extremely valuable. Echocardiography is used to assess the morphology of valves, the presence of vegetations, hemodynamic status, and the extent of endocarditis.

Endocarditis gives three typical findings on echocardiography:

Vegetations. Abscesses. Prosthetic detachment.

These three findings constitute the main criteria for diagnosing endocarditis. Traditionally, it has been considered that endocarditis can be diagnosed if at least two criteria exist.

Figure 1. Flow chart for the investigation of suspected endocarditis.

Vegetations

Vegetations are ecotate masses made up of the foci of infection. Vegetations can be found on the flaps and appear as moving masses. Mural vegetations are attached to the endocardium and, accordingly, less mobile.

Echocardiography is the first place method for detecting vegetation in case of suspicion of endocarditis. Transthoracic echocardiography (TTE) has a sensitivity of about 50% among them (this implies that 50% of all people with endocarditis will be diagnosed with TTE and, accordingly, 50% will be missed).

The sensitivity and specificity of echocardiography depend on several factors, such as image quality, vegetation localization, echogenicity and size, presence of valve prostheses, and the habit of the investigator. As with the clinical labor test (working ECG) , the value of echocardiographic examination depends on the pre-test probability,which is the probability that the patient actually has endocarditis (this the probability should be estimated before echocardiography is performed). Among patients with a very high probability of endocarditis, the sensitivity and specificity of the examination will increase, and vice versa.

In case of suspicion of endocarditis, transthoracic echocardiography (TTE) is initially done. If the images are of good quality and there are no signs of endocarditis, differential diagnoses should be considered first. If TTE is negative but clinical suspicion persists, transesophageal echocardiography (TEE) should be performed. TEE should always be performed if the patient has valve prostheses, as well as in difficult to assess cases and when the image quality with TTE is unsatisfactory. TEE should also be used if perivalvular complications are suspected, or if the infection is caused by highly virulent agents (e. g. beta-streptococci or staphylococcus auerus).

Native valve endocarditis

Transthoracic echocardiography (TTE) has low resolution and therefore low sensitivity to small vegetation compared to transesophageal echocardiography (TEE). TTE’s sensitivity is approximately 25% for vegetation <5 mm; 70% on vegetation 6-10 mm. Of course, sensitivity is affected by other changes in the body, such as myxomatous thickening or calcification.

TEE provides better resolution and increases the sensitivity and specificity of vegetation. In studies comparing the sensitivity to vegetation, TTE has a sensitivity of about 50% while TEE has sensitivity between 90-100%.

The negative predictive value (NPV) for TEE is between 86% and 97%. This implies that the absence of vegetation on the TEE implies that it is 86— 97% likely that the patient does not have vegetation. Among patients with native valves, this implies that endocarditis is very unlikely. However, it should be mentioned that if TEE is done early in the course, the TEE may also be negative, despite the fact that the patient has endocarditis (Sochowski et al ) . TEE should be made if the TTE is inconclusive or negative and suspicion persists.

Echocardiography should be performed very liberally in the following groups of patients:

Patients with bacteraemia with S. aureus. Patients with repeated bacteriaemia with the same agent without a clear focus. Patients with devices (pacemaker, ICD, CRT) with fever without clear focus.

Differential diagnoses in case of suspicion of endocarditis

Echocardiography can not distinguish infectious vegetations from aseptic vegetations. Several other conditions may give rise to aseptic vegetation, including:

Libman-Sack’s endocarditis (affects patients with SLE). Antiphospholipid syndrome.

Libman-Sack Endocarditis

Libman-Sack’s endocarditis is similar to infective endocarditis on echocardiography. However, this type of endocarditis is aseptic and the vegetation consists of immune cells, hematoxil bodies, coagulation factors and platelets. Libman-Sack’s endocarditis does not lead to the destruction of the valves, which is why the condition is less acute than bacterial endocarditis. This endocarditis most often has little hemodynamic influence, which is why most patients are asymptomatic. The absolute majority of patients have SLE (systemic lupus erythematosus).

Libman-Sack’s endocarditis most often affects the mitral valve and/or the aortic valve. Echocardiographically, it is difficult to distinguish these vegetations from bacterial vegetations. In addition, the aseptic vegetation can become the site of bacteria, in which a bacterial endocarditis occurs. In Libman-Sack endocarditis, embolization is rare, but it occurs.

Antiphospholipid syndrome is also associated with Libman-Sack’s endocarditis.

Prostethic valve endocarditis

Valvular prostheses complicate transthoracic diagnostics of endocarditis. Therefore, the TTE must be supplemented with TEE if the patient has valve prostheses. This applies to both mechanical and biological prostheses. The sensitivity of the TTE is 36 -69%, while the TEE has sensitivity of 86-94% and specificity 88 -100%.

Valve prostheses have several components that interfere with imaging, such as sewing collar, stent in percutane valve prostheses, discs in mechanical flaps, etc. These structures are ecotdense and give rise to artifacts that complicate the visualization of vegetation. In vegetations on the sewing collar, it appears thicker and more irregular. However, it is difficult to distinguish these changes from those seen in thrombosis and pannus formation.

Biological valve prostheses, like native valves, can be destroyed by endocarditis.

Right sided endocarditis

Right-sided endocarditis most often affects intravenous addicts, and vegetation, generally, is large. This means that TTE is usually enough to diagnose. Vegetations are found, generally, on the atrial side of the tricuspid valve. Studies show that TTE is as effective as TEE for endocarditis affecting tricuspidalis. However, for the pulmonary valve, TEE appears to have higher sensitivity and specificity.

Infected electrodes and devices

TEE has a higher specificity and sensitivity to endocarditis affecting electrodes and other devices. Sensitivity for TEE is 94% and for TTE 23%. Reverbations and other species factors make it difficult to detect endocarditis on electrodes with TTE.

Complications of endocarditis

Infected valves, generally, are insufficiency. This may be due to several causes, such as valve damage (native and biological valves), loosening of valve prostheses, or vegetation impairs coaptation (possibility for the cuss/discs to meet and close tightly).

Native and biological valves are permanently damaged by endocarditis. Damage varies from small perforations to total valve destruction. Perforation or destruction affects 50% of aortic endocarditis and 15% of mitral endocarditis.

If endocarditis engages chordae tendinae , the threads may detach from the valve, resulting in prolapse.

The infection can spread from the valves to surrounding tissues, which is associated with a worse prognosis. This can result in infections, abscesses, fistulas of the myocardium and perivalvular structures.

Perivalvular abscesses can affect all types of valves but are most common in valve prostheses. Abscesses have low echo density, which implies they are seen as darker, well-delimited areas on the 2D image. TTE has sensitivity and specificity of 28% and 99%, respectively, for abscesses. The corresponding figures for TEE are 87% and 95%.

Other investigation of endocarditis

Blood cultures are fundamental for diagnostics and treatment. Three pairs of bottles of 10 ml in each bottle are taken from 3 points. In about 10% of diagnosed cases, the cultures are negative. Blood tests: blood, electrolyte status. CRP. SR. Glucose. CRP is often only slightly moderately elevated (20-50 mg/l) with endocarditis lenta. Troponin. Echocardiography. See above. regular temperature controls; Lung and heart auscultation dailyresting ECGThenew appearance of AV blockade indicates an abscess. Arrhythmias are common; telemetry should be linked. Chest X-ray/DT thorax with a problem of heart failure, septic embolism. DT brain at focal neurological symptoms.

(none)

---

Chapter 4: Right ventricular strain: definition, causes, echocardiography

This chapter is available 2 days after the completion of the previous chapter.

Right ventricular strain

When assessing the right half of the heart, it is important to familiarize yourself with the principles of hemodynamics and conditions prevailing on the right side. Echocardiography is the first choice for assessing the right side of the heart, despite difficulties in visualizing it. Previously, the PA catheter ( Pulmonary Artery Catheter , also called Swan-Ganz catheter ) has been the first choice, but today the majority of patients can only be assessed using echocardiography.

A common question is the presence of right ventricular load. This condition implies that the right ventricle is pressure and/or volume loaded. The load itself leads to impaired right ventricular function, especially if the load becomes prolonged. However, most often the cause of the load is the primary problem. Among the causes are pulmonary embolism, pulmonary hypertension, septum defects, etc. Right ventricular load is thus an issue that is raised both in outpatient and emergency care. To evaluate the presence of right ventricular load, a variety of echocardiographic parameters are used.

Examination of the right ventricle with echocardiography

The right ventricle is relatively difficult to examine, which is due to the location of the ventricle in the thorax. It is localized immediately behind the sternum and thus is the most anteriorly located part of the heart. The right ventricle has a complicated anatomy. In cross-section (SAX, short-axis view), the the ventricle is rather a crescent-shaped appendage of the left ventricle. On longitudinal sections (A4C, apical four-chamber view), the right ventricle is a triangular structure (Figure 1).

Figure 1. SAX (short axis view), where the right ventricle appears as a crescent-shaped appendage of the left ventricle.

Systolic function of the right ventricle

The systolic function of the right ventricle is primarily a function of the following parameters:

Contractility of the myocardium: all causes of reduced contractility, globally or regionally, lead to impaired right ventricular function. Preload: Preload is the volume of blood flowing from the right atrium to the right ventricle. Afterload: Afterload is the resistance that the the ventricle must overcome to pump blood out into the pulmonary artery. Resistance may increase in, for example, pulmonary hypertension or pulmonic stenosis. Heart rate. Synchronicity: Optimal contraction requires the majority of all ventricular myocardium to contract simultaneously. For this to be possible, the right leg must be intact. In the case of blockade of the right bundle of His (RBBB) , the ventricle can not depolarize normally, which affects the efficiency of contraction.

Left ventricular function affects right ventricular function via afterload. In the case of left ventricular failure, the pressure in the pulmonary vessels rises and the pressure rise propagates to the right ventricle.

Pulmonary vascular resistance (PVR)

Vascular resistance (R) is the resistance that must be overcome to force blood through a blood vessel. Vascular resistance is calculated by the ratio of the pressure difference (ΔP) and the flow over the vascular bed (Q):

R = ΔP/Q

Both ΔP and Q above the pulmonary vessels can be calculated by echocardiography, which makes it possible to calculate the resistance in the pulmonary vessels (pulmonary vascular resistance, PVR). This parameter is of utmost interest in investigating right ventricular load.

Pressure in the right atrium (right atrial pressure)

With the PA catheter (Swan-Ganz catheter), the right atrial pressure can be measured directly. Echocardiography (UCG) allows an indirect estimation of atrial pressure. This is done by assessing the diameter of the vena cava inferior and whether the diameter varies during the respiratory cycle. Thus, the pressure in the inferior vena cava is used as a proxy for pressure in the right atrium, which is possible because there is normally no valve between the vena cava and the right atrium. The following assessments are made for vena cava inferior:

Diameter: Normally the diameter is less than 21 mm. How much does the diameter decrease during inspiration (tested by asking the patient to sniff). Normally, diameter decreases > 50% when inhaled or sniffing.

The measurement is made in the subcostal view (parallel to the longitudinal axis of the vena cava inferior ) after the departure of the hepatic veins, at the end of the exspiry. The patient should be lying on his back (the diameter varies with the body position). If the diameter is >21 mm or the decrease is < 50%, the pressure in the right atrium is higher than normal. The following thumb rules are used to estimate atrial pressure:

Normal diameter and respiratory variability: pressure is estimated at 3 mmHg (0-5 mmHg)Normal diameter but reduced respiratory variation: pressure is estimated to be 8 mmHg (5-10 mmHg). Increased diameter and reduced respiratory variability: pressure is estimated at 15 mmHg (10-20 mmHg).

This estimate becomes uncertain if there is a pronounced tricuspid regurgitation insufficiency (TI). Likewise, it may be affected by the patient’s involvement and ability to ventilate. Athletes and younger people do not rarely exhibit a dilated vena cava inferior as a normal variant. Last but not least, some individuals have a valve between the inferior vena cava and right atrium; about this valve (eng. eustachian valve) is prominent, so the pressure in the right ventricle can differ significantly from the pressure in theinferior vena cava, and the pressure in the latter can not be used as a proxy for pressure in the atrium. (A prominent flap tends to prevent vena cava inferior from collapsing during inspiration, giving false elevated values).

Systolic right ventricular pressure (RVSP, Right Ventric Systolic Pressure)

The systolic pressure in the right ventricle can be calculated if there is a tricuspid regurgitation insufficiency, which is present in the majority of all people. With Doppler, the maximum rate of tricuspid insufficiency is recorded, which is then used in the following formula to estimate the pressure difference between the right atrium and the right ventricle:

ΔP = 4v2

Then the estimated atrial pressure (measurement of the diameter of the vena cava inferior ) is added to ΔP, giving RVSP:

RVSP = ΔP + atrial pressure

Systolic PA pressure (PASP, Pulmonary Arterial Systolic Pressure)

PASP is equivalent to RVSP:

RVSP = PASP

This is provided that there is no obstruction between the right ventricle and the pulmonary artery. If obstruction exists, the pressure gradient is calculated over the RVOT and then the PASP is calculated according to the following:

PASP = RVSP – ΔPRVOT

Diastolic PA pressure (PADP, Pulmonary Arterial Diastolic Pressure)

In pulmonic regurgitation (PI), the maximum rate of leakage can be used to measure diastolic pressure in the pulmonary artery. First, the maximum rate of insufficiency is measured, with which the pressure difference is calculated:

ΔP = 4v2

ΔP and right atrial pressure are added to obtain PDAP:

PDAP = ΔP+ atrial pressure

MPAP (Mean Pulmonary Artery Pressure)

MPAP = (PSAP+ 2•PDAP) /3

MPAP can also be measured with pulsed wave doppler in RVOT. The acceleration time of the Doppler recording (AT, measured in milliseconds) is used in the following formula:

MPAP = 79 – 0.45•AT

If AT is <120 ms, the adjusted equation is used:

MPAP = 90 – 0.62•AT

This calculation is an uncertain left-to-right shunt (defect of the interatrial septum), bradycardia or tachycardia.

Pulmonary Vascular Resistance (PVR)

Pulmonary vascular resistance is calculated as the ratio between the pressure difference and the flow across the small circle of circulation:

PVR = ΔP/Q

ΔP and Q are estimated by the following parameters:

vmaxTI – If there is a tricuspid regurgitation insufficiency, its maximum rate can be measured and this gives an indication of the pressure drop over the lungs. The measurement is done with continuous wave doppler in apical four-chamber view . VTIRVOT – VTI in RVOT is used to estimate the flow over the lungs. The measurement is made in parasternal kortaxevyl with pulsed wave doppler.

After that, the following formula is used to damage PVR (mmHg):

vmaxTI /VTI

If the above quota is >0.175, PVR is likely to be increased (greater than 2 Wood Units).

If the ratio is 0.175 — 0.275, the following formula is used to estimate PVR (mmHg):

PVR = 10 • (vmaxTI/VTIRVOT)

Right ventricular load

In a series of conditions, pressure and/or volume load may rise in the right ventricle. This gives right ventricular load. Among the causes of right ventricular load are the following:

Pulmonic stenosis(PS) – this, generally, is a congenital heart malformation.Pulmonary hypertension (primary, secondary) – high resistance of pulmonary vessels provides increased afterload for the right ventricle. Primary pulmonary hypertension is idiopathic. Among the causes of secondary pulmonary hypertension are pulmonary embolism, COPD (chronic obstructive pulmonary disease) and connective tissue diseases of the lungs.Atrial septal defect – Since the pressure in the left atrium is higher than the pressure in the right atrium, the blood will be shunted from left to right, and the right side will be volumetric.Tricuspid regurgitation – this is most often secondary to carcinoid heart disease or endocarditis.Left ventricular dysfunction.

Under pressure and/or volume load, the right ventricle becomes dilated and this spreads to the right atrium, which is also dilated. The pressure in the right ventricle can become so high that the septum bulges into the left ventricle. High ventricular pressure also leads to tricuspid regurgitation insufficiency.

The most common of the above causes is left ventricular dysfunction. Dysfunction leading to increased pressure in the left ventricle can spread to the left atrium, to the pulmonary vessels and further to the right ventricle. The echocardiographic parameters that are of interest in this situation are the pressure in the pulmonary artery (PA pressure), as well as the resistance in the pulmonary vessels (PVR, Pulmonary Vascular Resistance).

In the case of signs of right ventricular load, it is fundamental to determine whether the load is due to increased resistance in the pulmonary vessels (increased PVR) or to increased pressure in the left ventricle. If left ventricular function is normal and the filling pressure in the left ventricle is normal, then increased PVR is the most likely explanation of right ventricular load. At high filling pressure on the left side, right ventricular load may be due to the propagation of pressure rise back to the right ventricle. At very high PA pressure without concomitant pulmonary edema, left ventricular function is likely to be normal.

(none)

---

Chapter 5: Cardiac tumors

This chapter is available 2 days after the completion of the previous chapter.

Cardiac tumors

Cardiac tumors are rare. They can occur anywhere in the heart or surrounding tissue. Tumors can be localized in the myocardium, pericardium, perivalvular (adjacent to the valves), etc. Cardiac tumors cause nonspecific symptoms that depend on the size of the tumor, localization, hemodynamic effects and possible impact on the coronary arteries. The tumors can be asymptomatic for a long time and be detected randomly when investigating other conditions. More dramatic onset of symptoms can be seen in arrhythmogenic tumors of the myocardium; in these cases, the tumor can debut with ventricular arrhythmias that result in asystole and sudden death.

In echocardiography, tumour should be suspected in case of detection of ecotdense tissue masses. However, the majority of all ecotate masses are vegetations (endocarditis) and thrombi. Only a minority of all ecotaceous masses are tumors. Most of all cardiac tumors are secondary, and the primary cardiac tumors, generally, are benign.

Primary and secondary cardiac tumors

• Primary cardiac tumors, which constitute a minority of cardiac tumors, occur in the heart tissue. Approximately 80% of all primary tumors are benign, and the remaining ones are malignant. • Secondary cardiac tumours have spread to the heart by metastasis or invasion from surrounding tissue.

Differential Diagnostics

There are several differential diagnoses in the case of cardiac masses. The characteristics of the patient, the size and localization of the mass are indicative in diagnostics. A patient who exhibits an ecotdense mass entrenched in the endocardium with impaired mobility (for example, after myocardial infarction), most likely has a parietal thrombus. The presence of ecotdense masses on valves should lead to suspicion of endocarditis (the masses are vegetations). The risk of endocarditis is especially high for patients with valve prostheses.

Investigation of cardiac masses

Detection of cardiac masses with echocardiography most often entails additional investigation, which is aimed at clarifying the genesis of the mass. Transesophageal echocardiography (TEE), magnetic resonance imaging (MRI of the heart) and computed tomography (DT of the heart) are appropriate investigative options. Three-dimensional (3D) echocardiography is likely to have increased significance in these studies in the future.

Hemodynamic effects of cardiac tumors

The hemodynamic effect of the tumor depends on its size and location. Tumors can reduce cardiac output by causing obstruction or valve dysfunction. Tumors that grow invasively in the myocardium can cause arrhythmias, which in turn can cause hemodynamic effects (impaired cardiac output).

Benign primary cardiac tumors

Most (75%) of all primary cardiac tumors are benign. Among adults, most of them are myxomas and next papillary fibroelastoma is most common. Among children, rhabdomyoma is most common.

Myxoma

Myxoma is the most common primary cardiac tumor. These tumors most often debute at the age of 30-60 years and are more common among women. Approximately 80% of all myxomas are localized in the left atrium (most of them originate from the atrial septum). In 15 -20% of cases, the tumor is localized in the right atrium. Myxoma is rare in the valves and ventricles.

Myxoma, generally, is mobile structures. Polypoid myxomas are large; they have a smooth surface and a nucleus that often exhibits cavities, which consist of hemorrhages in the tumor. Polypoid myxoma usually causes haemodynamic complications due to obstruction. Papillary myxomas are small; they have a more stretched appearance and most often exhibit multiple villi. These myxomas are more likely to embolize (Cardiac Thromboembolism).

There are genetic syndromes that result in the emergence of multiple myxomas.

Papillary fibroelastoma

Papillary fibroelastoma is benign primary tumors affecting adults. These tumors most often occur in the aortic valve and the mitral valve. generally, tumors are 2 to 40 mm. They usually have a stalk and are very mobile. The structure of the tumor is reminiscent of a sea anemone. Although most fibroelastomas are located on the valves, they usually cause no or only small valve dysfunction. However, papillary fibroelastoma carries a risk of thromboembolic events (TIA, stroke).

Left-sided fibroelastoma that is >1 cm is usually removed operatively. Right-sided are removed if they are large and entail hemodynamic complications, or if they pose a risk of thromboembolism (for example, through the persistent oval foramen [PFO] with right to left shunt).

Rhabdomyoma (rhabdomyoma)

Rhabdomyoma is the most common primary tumor among children and the tumor is most often detected in the first year of life. These children often have tuberous sclerosis. Rhabdomyoma is rare among adults.

Rhabdomyoma is most often localized on the wall of the ventricle, alternatively on the mitral or tircuspid valve. Tumors are seen on echocardiogram as small, well-delimited tubers or stemmed masses. Rhabdomyoma can be embedded in the myocardium.

Rhabdomyoma most often goes into spontaneous regress and most often does not require treatment.

Fibromium

Fibroma is rare but affects both adults and children. These tumors are well-delimited, solid, high-echogenic masses inside the myocardium. Fibroma may be calcified.

Most fibromas are localized on the free wall of the left ventricle, anterior wall or septum. However, the growth in the ventricular cavity seen, which can lead to obstruction and heart failure. Fibroma growing in the myocardium can provoke arrhythmias.

Fibroma rarely goes into spontaneous regress and usually needs surgery removed. People with Gorlin’s syndrome have multiple basal cell carcinomas and fibromas of the heart.

Lipoma

Cardial lipoma consists of benign adipose tissue. They occur most often in the subendocardium or on the heart valves. Most often, the lipoma is a couple of millimeters in diameter, but they can become several centimeters. On echocardiograms, lipomas appear as immobile, broad-basal structures that are well delimited to the environment. The contents are homogeneous and there are no calcifications. Lipomas in ventricular cavity are echo tight, while the lipomas of the pericardium are ecophilious.

Lipoma, generally, is asymptomatic. They can give symptoms through arrhythmias or valve dysfunction. Epicardially located lipomas can cause compression of the coronary arteries, thereby causing myocardial ischemia and chest pain . Since lipoma has a tendency to grow, surgery may be necessary.

Lipomatous hypertrophy of the atrial septum

A special form of fat deposits is sometimes seen in the atrial septum and this is especially common among the elderly and overweight. These fat deposits are seen mainly in the proximal and distal parts of the atrial septum. Fat deposits are not tumors and they rarely need to be addressed.

Other benign primary tumors of the heart

In the heart, albeit very rarely, hemangiomas, tumors of the AV node and teratoma occur. Hemangioma can occur anywhere in the heart (myocardium, pericardium, heart valves). Teratoma occurs in the pericardium.

Malignant tumors of the heart

Approximately 20% of all primary cardiac tumors are malignant. These are much more common on the right half of the heart, where almost 50% of tumors are malignant. Malignancy is usually accompanied by invasiveness, rapid growth and hemorrhagic pericardial deffusion.

Sarcoma of the heart

Sarcoma is the most common malignant primary tumor of the heart. The average age at debut is 40 years. Sarcoma most often affects the left atrium. The tumor has a wide base with varying echogenicity. Sarcoma has no stalk. These tumors tend to metastases, especially to the lungs.

The most common types of sarcoma are angiosarcoma and rhabdomyosarcoma . Less common are leiomyosarcoma, osteosarcoma, fibrosarcomaand undifferentiated sarcoma. All sacromas grow rapidly and metastasize early.

Lymphoma of the heart

Lymphoma often metastasizes to the heart. Autopsy studies show that 16% of patients with Hodgkin’s lymphoma and 18% of patients with non-Hodgkin’s lymphoma have metastases in the heart.

Lymphoma may also occur in the heart, especially B-cell lymphoma, and this is seen in transplanted patients and other immunosuppressed patients. Lymphoma most often affects the right half of the heart, especially the right atrium.

Lymphomas appear as homogeneous infiltrates on ultrasound. They can, depending on their size and localization, cause extensive hemodynamic disorders.

Mesothelioma (Mesothelioma)

Mesothelioma (malignant) makes up about 50% of primary tumors of the pericardium. Other tumors of the pericardium (teratoma, fibroma, lipoma) are benign. Mesothelioma can be seen in the pericardium, which usually contains an effusion.

Metastases to the heart

Autopsy studies show that up to 7% of all people with cancer have metastases in the heart. Metastases can reach the heart via the blood (hematogenous spread), by direct invasion from the environment (tumors in the mediastinum, lungs), via the lymph or via the inferior vena cava.

Lung cancer, oesophageal cancer, malignant melanoma, leukemia and lymphoma are the tumors that most often metastases to the heart. The highest propensity to metastases to the heart has malignant melanoma. In the case of metastases to the heart, the pericardium is also engaged, which leads to pericardial effusion.

(none)

---