13 Cardiomyopathies

Cardiomyopathy: Required Parameters to Obtain from Scanning

Left ventricle (LV)–focused ventricular function views

Right ventricle (RV)–focused ventricular function views

Cardiac output, cardiac index, right ventricular systolic pressure, left ventricular ejection fraction (LVEF%)

• Pericardial pathologies (pericardial constriction is the classic differential diagnosis of restrictive cardiomyopathy)

Consideration of

• The specific forms of cardiomyopathy and of myocarditis ¹

• Whether valvular dysfunction is secondary to myopathy, associated with myopathy, or responsible for the ventricular dysfunction.

2006 American Heart Association Definitions and Classification of Cardiomyopathies ²

Primary cardiomyopathies

• Genetic

Hypertrophic cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy/dysplasia

LV noncompaction

Conduction system disease

Mixed (genetic and nongenetic)

• Dilated cardiomyopathy

• Hypertrophic cardiomyopathy (nonobstructive/obstructive)

• Primary restrictive nonhypertrophied cardiomyopathy

Acquired

• Myocarditis

• Stress (“tako-tsubo”) cardiomyopathy

• Others

Secondary cardiomyopathies

• Neuromuscular/neurologic

• Nutritional deficiencies

• Autoimmune

• Electrolyte imbalance

• Consequence of cancer therapy

Dilated (Congestive) Cardiomyopathy

Hallmark findings

• Globally depressed systolic function

• “Spherical” cavitary dilation

• “Functional” moderate mitral regurgitation (MR) and tricuspid regurgitation (TR)

Because dilated cardiomyopathy is the common expression of various types of myocardial insult, including coronary artery disease, echocardiography alone cannot establish the underlying diagnosis. Cases of dilated cardiomyopathy often have regional differences in contractile function; conversely, some cases of “ischemic” cardiomyopathy have exactly uniform global contractile dysfunction. Therefore, wall motion assessment cannot reliably distinguish the two. Furthermore, contractile dyssynchrony contraction from an intraventricular block renders interpretation difficult.

Goals of Echocardiography in Dilated Cardiomyopathy

To establish high probability of the diagnosis of dilated cardiomyopathy

To exclude significant valvular, congenital, and pericardial disease

To identify complications such as intracavitary thrombi

To calculate right ventricular systolic pressure and cardiac output

Echocardiographic Features of Dilated Cardiomyopathy

Two-Dimensional

Increased chamber dimensions

• Typically of all four chambers

• Left-sided chamber enlargement greater than right-sided enlargement may occur

• 5% to 10% of the time, a “minimally dilated” picture with near-normal dimensions and reduced systolic function is present.

Increased ventricular mass

• Dilated cardiomyopathy is the perfect example of discordance of LV wall thickness with LV mass (left ventricular hypertrophy), as the LV wall thickness is usually normal but the chambers are dilated. LV mass is increased; often to 500 to 600 g. In advanced states, the walls may appear thinner, although this is as much an issue of relative appearances prompted by the overwhelming impression of chamber dilation.

Tendency to spheroid chamber shapes

Decreased systolic function

• Most obviously of the ventricles

• Global pattern is the most common.

• Segmental contraction abnormalities may occur. Regional wall motion abnormalities do not exclude dilated cardiomyopathy; conversely, some cases of ischemic cardiomyopathy exhibit uniformly global hypokinesis.

Mural thrombi

• Found in 75% of non-anticoagulated hearts at autopsy

• Left ventricular apex > right ventricular > apex atria

• Frequently in more than one chamber

Distortion of the tricuspid and mitral apparati by ventricular and annular dilation occurs, resulting in mild/moderate (seldom severe) insufficiency.

• Typically, the leaflets are of normal thickness, but distorted with apical displacement of the coaptation point (“tenting”), “tethering” and a central jet—the findings typical of “functional MR.”

• Severe MR is uncommon in DCM and begets consideration of (1) specific valve pathology and (2) whether MR resulted in ventricular dysfunction.

Cardiac output is reduced, initially on exertion, but later in the resting state. Severely reduced stroke volume is evident on two-dimensional imaging as a flicker of valve opening, rather than sustained opening. The “low-output” appearance of the aortic valve is most easily seen on M-mode.

Increased end-point to septal separation is classically seen and reflects the combination of cavitary dilation and systolic dysfunction.

The presence of a “restrictive pattern” of ventricular inflow is seen in more advanced cases, typically with the onset of clinical heart failure, and independently predicts a worse prognosis. Lack of improvement of the restrictive pattern with medical therapy establishes an index of refractoriness to therapy, and an even worse prognosis.

RV systolic pressure represents the sum total of the combined forces of hydrostatic back pressure, reactive pulmonary hypertension, and failing contractile function of the right heart due to myopathy of the right ventricle itself.

“Mildly dilated cardiomyopathy” is a variant syndrome characterized by severe congestive heart failure (CHF) with low ejection fraction, but only minimal chamber dilation.³ It carries a poor prognosis, similar to that of dilated cardiomyopathy.

Hypertrophic Cardiomyopathy

Noninvasive imaging has a central role in the recognition of and evaluation of hypertrophic cardiomyopathy.⁴

Goals of Echocardiography in Hypertrophic Cardiomyopathy

To establish morphologic and functional characteristics consistent with hypertrophic cardiomyopathy (the “phenotype”)

To map the distribution of the hypertrophy within the ventricles

To establish that the level of obstruction, if present, is at the muscular and not at the aortic valve level

To identify obstruction at the right ventricular outflow tract (RVOT) level if present

To identify complications of hypertrophic cardiomyopathy, such as

• Resting and provokable outflow gradients

• MR

• Endocarditis

Echocardiographic Features of Hypertrophic Cardiomyopathy

Two-Dimensional and Real-Time Imaging

Echocardiographic features of hypertrophic cardiomyopathy include a small or normal-sized LV cavity in 95% of cases.

Left ventricular hypertrophy with increased wall thickness also may be seen:

Increased LV wall thickness, typically >15 mm.

Note the maximal thickness; it is a marker of clinical risk.

Note the pattern of hypertrophy.

• Basal septal hypertrophy is prone to left ventricular outflow tract (LVOT) obstruction.

• Mid-septal hypertrophy (<10%) is prone to midventricular obstruction.

• A mid-LV tunnel may be the result of prior apical infarction, and may have a higher incidence of progression into a dilated hypokinetic left ventricle.⁵

• Apical hypertrophy (<5%) is not prone to obstruction, but is prone to failure of recognition.

• Generalized hypertrophy (5%) may have associated obstruction at the LVOT level.

• Dilated stage of hypertrophic cardiomyopathy (<10% of all cases of hypertrophic cardiomyopathy), a terminal phase, with refractory CHF ⁶

Increased RV wall thickness is seen in 15% to 20% of patients. Decreased septal movement, especially of the base, with increased movement of the posterior wall, also may be present. Findings of muscular outflow obstruction include the following:

LVOT or right ventricular outflow tract systolic narrowing

Systolic anterior motion (SAM) of the mitral leaflets

A “contact plaque” in the LVOT is seen in many patients with hypertrophic obstructive cardiomyopathy (HOCM), although this is poorly proven as a sign of HOCM.

Evidence of flow acceleration at the base of the LVOT usually is abundantly clear from color Doppler flow mapping; pulsed-wave Doppler is only confirmatory. Continuous wave Doppler is required to establish maximal velocity and gradient. Doppler estimated peak dynamic gradients correlate well with peak catheter gradients: r = 0.96, SEE 3.9 mm ⁷ and r = 0.93–0.89,⁸ respectively.

The spectral profile typically is late-peaking (“dagger-shaped”) and often provokable by maneuvers that reduce LV size.

Intracavitary obstruction may occur at the

It is important that two-dimensional imaging adequately exclude other causes of subvalvar stenosis (congenital fibrous ridges and tunnels), as they are essentially surgical lesions.

Mitral morphologic abnormalities such as the following may occur:

Thickening of the anterior mitral leaflet (in 75%)

Elongation of the anterior mitral leaflet

Thickened chordae

Papillary muscle abnormalities

• Prominently hypertrophied papillary muscles may insert directly into the mitral leaflets.⁹

• Mitral valve prolapse: 3%¹⁰

Annular calcification

MR is common, especially if there is outflow obstruction, because the anterior traction on the leaflets may compromise coaptation and result in (typically) posteriorly directed MR. (However, outflow obstruction does not have to be present.) In HOCM, MR is actually holosystolic, although the bulk of it occurs in later systole.¹¹ Mitral insufficiency occurs as the anterior mitral leaflet or posterior mitral leaflet is pulled out of coaptation alignment, but may also occur secondarily to traumatic chordal rupture¹² or to infective endocarditis of the mitral valve producing infective chordal rupture.

Mild aortic insufficiency is common, and results from either

• The impact of the outflow jet resulting in sclerosis of the aortic valve

• Myotomy/myectomy (i.e., valve trauma or altered suspension).

Dyssynchronous LV relaxation (apex relaxing before the rest of the LV does) may produce an apically directed isovolumic relaxation time jet of about 2 m/sec.

Obstruction

Obstruction occurs from the following:

A small LVOT—due to encroachment of the basal septum by the hypertrophied septum

Possible abnormally anterior mitral valve position

Hypercontractile state

SAM

Systolic Anterior Motion

SAM correlates with gradient, but cause versus effect remains unclear, and somewhat moot.

SAM is not (at all) specific for hypertrophic cardiomyopathy. In states other than hypertrophic cardiomyopathy, SAM often is chordal, and less often involves the leaflets—and, therefore, less often is associated with mitral insufficiency.

Grading SAM is less important than measuring the associated gradient.

Echocardiographic and Surgical and Catheter Options for Hypertrophic Obstructive Cardiomyopathy

Echocardiography has an important role in the surgical (myotomy/myectomy) treatment of HOCM, which is a successful intervention to reduce symptoms. It provides the following:

Optimal definition of the LVOT anatomy

Exclusion of membranes or tunnels

Confirmation of adequate thickness of the septum to withstand myotomy/myectomy (to avoid iatrogenic ventriculoseptal defect)

Ethanol ablation of the basal septum is a rival procedure in which infusion of alcohol into the basal septal perforator branch of the left anterior descending artery intentionally results in chemical necrosis of the septum, reducing its bulk, and the obstruction.

Infusion of echocardiographic contrast into the septum during catheterization has been used to “map” the vascular territory of the first septal perforator branch of the left anterior descending artery, although the role of this is unproven.

The mechanism of MR in a case of HOCM is most likely to be unraveled by echocardiography, assisting with the consideration of the merit of mitral valve replacement in HOCM.

Role of Treansesophageal Echocardiography in the Surgical Management of Hypertrophic Obstructive Cardiomyopathy

TEE plays a role in the surgical management of HOCM:

Aid in the decision of feasibility/appropriateness of myocardial myotomy/myectomy—specifically, is the basal interventricular septum too thin to withstand the myocardial myotomy/myectomy without excessive risk of ventricular septal defect formation?

Is mitral valve replacement more appropriate?

Have there been complications with the procedure?

Exclusion of ridge or tunnel

Echocardiography is the usual test chosen to assess the hemodynamic effects of therapy (medical and surgical):

Systolic parameters

• Reduction in SAM

• Reduction of LVOT gradient

• Reduction of mitral insufficiency

Apical Ballooning Syndrome

The apical ballooning syndrome (also known as transient apical ballooning, tako-tsubo [“octopus pot”], or stress cardiomyopathy) is a syndrome of relatively recent recognition that has several notable features. There is a large predominance of female patients, and often a preceding major physiologically or psychologically stressful circumstance (e.g., bereavement). Although the electrocardiographic changes are striking, biomarker elevations are discordantly only mildly abnormal, consistent with myocardial stunning. Despite the fact that some patients present with heart failure or even cardiogenic shock, more than 90% of them will survive, and the ventricle usually normalizes within 3 months, also consistent with stunning. High-grade arrhythmias may occur, and about 10% of patients will experience a recurrence of the syndrome. The cause is debated, but unknown. Initially described in Japanese, it is now recognized to occur across races.¹³

The numerous names for the same syndrome are unfortunate: apical ballooning syndrome and transient apical ballooning are clear, descriptive, and without implication of cause; tako-tsubo, the authentic name of the Japanese octopus pot trap, is exotic and descriptive; stress cardiomyopathy, a term preferred by some, implies causality, which is not well understood to date.^14,¹⁵

Any modality that can image LV geometry and depict systolic function can be used to diagnose apical ballooning, after CAD has been excluded. Echocardiography is likely the most commonly used test to recognize the peculiar combination of marked apical dilation (“ballooning”) and apical akinesis.

Restrictive and Infiltrative Cardiomyopathy

Examples

Idiopathic

Amyloidosis

Endomyocardial fibroelastosis

Echocardiographic Findings

Myocardial or endocardial thickening

Normal or small ventricular cavity sizes, until late in the course

Biatrial enlargement (may be massive)

Normal systolic function, at least early

Diastolic inflow abnormalities

Diastolic mitral insufficiency would indicate very elevated LV end-diastolic pressure.

Endomyocardial Fibrosis

Endomyocardial fibrosis, also known as eosinophilic endomyocardial disease, results in a restrictive cardiomyopathy syndrome. Subendocardial eosinophilic infiltrates produce necrosis, thrombosis, and fibrosis, resulting in a thick endocardial “peel” that confers diastolic heart failure and has embologenic potential. The apices and ventricular inflow areas often are prominently involved.

The most prominent feature is the thickened echogenic “peel” of endocardial fibrosis within the ventricles, frequently obliterating the apices. In most cases, there is preservation of underlying ventricular systolic function. Overlying thrombus is common; peripheral and pulmonary embolization may occur. Endomyocardial fibrosis is one of the few diseases where apical thrombi occur in the context of normal ventricular systolic function.

Involvement of the basal ventricles and papillary muscles, and adherence of valve leaflets, may lead to mitral and tricuspid insufficiency.

Cardiac Amyloidosis

Infiltration of the heart by the tough, rubbery amyloidosis material results in a range of clinical severity, and a spectrum of echocardiographic findings. Cardiac amyloidosis is the prototype of diastolic heart failure, and the prototype form of restrictive cardiomyopathy, for which the term “restrictive filling pattern” was coined. Infiltration is ubiquitous within the heart; therefore, all walls and valves become thickened, all valves become prone to mild/moderate degrees of insufficiency, and small pericardial effusions are the norm.

Echocardiographic Findings of Cardiac Amyloidosis

Thick-walled ventricles

• LV: >15 mm in half of cases

• RV: >7 mm in half of cases

Wall thickening generally tracks the chronologic and clinical course of the disease.

• Early disease: LV <15 mm and RV <7 mm

• Late disease: LV >15 mm and RV >7 mm.

• The greater the wall thickness, the more frequent and severe the CHF, and the worse the survival.¹⁶

Cavitary dimensions usually are normal or small until late in disease when dilation may occur.

Only half of cases (47%) exhibit “characteristically” bright, refractile, and granular myocardial appearance. This perceived appearance is not specific for amyloidosis, and is notoriously inter-physician variable.

Systolic function is well preserved through the early part of the disease, and there may even be hypercontractility from anemia and low intravascular volume.

Thickened valves

Mitral insufficiency: 90%, usually mild to moderate

Tricuspid insufficiency: 70% to 80%, usually mild to moderate

• Severe in 20%

Aortic insufficiency: 43%, usually mild to moderate

Pulmonary insufficiency: 23%, usually mild to moderate

Thickened interatrial septum (infiltration with amyloid)

Pericardial effusions: 85%

Severe hypertrophy (infiltration) of the base of the septum may occasionally result in LVOT obstruction, with the usual findings of SAM and unstable gradients.

The association of ventricular inflow diastolic flow patterns with disease severity was first mapped out in amyloidosis. Early in the course of disease, an “abnormal relaxation” pattern of right ventricular and left ventricular inflow is evident. With clinical worsening of cardiac function, this may transiently (pseudo) normalize and then latterly and terminally evolve into a restrictive pattern. Progression to death is then usually rapid, in 1 to 2 years. Doppler filling patterns may thus predict the time course.¹⁷^–¹⁹

There are several different syndromes of cardiac/cardiovascular amyloidosis, and the pathophysiology is not entirely explained by diastolic failure:

Restrictive cardiomyopathy/diastolic heart failure

Restrictive cardiomyopathy with LVOT obstruction, SAM, mitral insufficiency ²⁰^–²²

Restrictive cardiomyopathy with right ventricular outflow tract obstruction

Dilated cardiomyopathy-like (predominant systolic dysfunction) terminal phase

Orthostatic hypotension in 10% from dysautonomia, with or without intravascular hypovolemia from nephrosis

Pseudo-infarction pattern on electrocardiography; abnormal electrical impulse formation and conduction

The combination of low voltages on the electrocardiogram and increased septal thickness (>19 mm) has the following predictive value:²³

Sensitivity: 72%

Specificity: 91%

Positive predictive value: 79%

Negative predictive value: 88%

Cardiac Sarcoidosis

Cardiac involvement by sarcoid granulomas results in a dilated cardiomyopathy syndrome, frequently with regional wall motion abnormalities. Patients with cardiac sarcoidosis with conduction defects generally have granulomas in the base of the septum. Treatment with corticosteroids may result in LV aneurysm formation. As with amyloidosis, sarcoidosis severe enough to produce overt heart dysfunction is seldom limited to the heart.

Cardiac Hemochromatosis

Cardiac involvement by hemochromatosis results in a dilated cardiomyopathy syndrome. Valve function is unaffected.

The characteristic patient is male, with the other usual systemic features of the disorder, and suffers from CHF with or without arrhythmias and conduction problems. Cardiac causes of death are still the most common. Phlebotomy may improve indices of systolic function,²⁴ as may desferrioxamine.

Chagas Disease

Chagas disease, caused by the parasite Trypanosoma cruzi after a bite by the reduvid bug, results in myocardial dysfunction in about one third of cases.

Dilated nonsegmental and nondilated segmental forms occur. Half or more of patients have an apical aneurysm that is indistinguishable from that produced by CAD. Approximately one third have a typical dilated cardiomyopathy picture that is indistinguishable from that due to idiopathic dilated cardiomyopathy.²⁵ Both the left and right ventricular apices may be aneurysmal and have thrombi (>50%). CHF, conduction disturbances, arrhythmias, and systemic and pulmonary emboli are common.

Myocarditis

In early fulminant myocarditis, myocardial walls may be thickened with inflammation and edema; this observation is more often true in children than in adults. Global loss of systolic function is characteristic, and dilation may occur. Some regional variation of involvement or systolic dysfunction may occur.

The presentation may be so fulminant as to appear as myocardial infarction with severe heart failure or even shock.

BOX 13-1 Appropriateness Criteria and Indications for Cardiac Imaging Modalities and Cardiac Catheterization for the Assessment of Suspected Dilated Cardiomyopathies

Transthoracic Echocardiography

ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 Appropriate Use Criteria for Echocardiography ²⁶

ACC/AHA 2003 Guideline Update for the Clinical Application of Echocardiography ²⁷

Recommendations for Echocardiography in Patients with Dyspnea, Edema, or Cardiomyopathy

Class I

• Dyspnea with clinical signs of heart disease

Class IIb

• Re-evaluation of patients with established cardiomyopathy when there is no change in clinical status but when the results might change management

Class III

• Routine re-evaluation in clinically stable patients in whom no change in management is contemplated and for whom the results would not change management

ACC/AHA 1997 Guidelines for the Clinical Application of Echocardiography ²⁸

Indications for Echocardiography in Patients with Dyspnea, Edema, or Cardiomyopathy

For assessment of LV size and function in patients with suspected cardiomyopathy or clinical diagnosis of heart failure ^*

• Class I

For edema with clinical signs of elevated central venous pressure when a potential cardiac etiology is suspected or when central venous pressure cannot be estimated with confidence and clinical suspicion of heart disease is high ^*

• Class I

For dyspnea with clinical signs of heart disease

• Class I

For patients with unexplained hypotension, especially in the intensive care unit ^*

• Class I

For patients exposed to cardiotoxic agents, to determine the advisability of additional or increased dosages

• Class I

For re-evaluation of LV function in patients with established cardiomyopathy when there has been a documented change in clinical status or to guide medical therapy

• Class I

For re-evaluation of patients with established cardiomyopathy when there is no change in clinical status

• Class IIb

For re-evaluation of patients with edema when a potential cardiac cause has already been demonstrated

• Class IIb

For evaluation of LV ejection fraction in patients with recent (contrast or radionuclide) angiographic determination of ejection fraction

• Class III

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Jun 12, 2016 | Posted by admin in CARDIOLOGY | Comments Off

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Thoracic Key

Fastest Thoracic Insight Engine

Cardiomyopathies

Cardiomyopathy: Required Parameters to Obtain from Scanning

2006 American Heart Association Definitions and Classification of Cardiomyopathies ²

Dilated (Congestive) Cardiomyopathy

Goals of Echocardiography in Dilated Cardiomyopathy

Echocardiographic Features of Dilated Cardiomyopathy

Two-Dimensional

Hypertrophic Cardiomyopathy

Goals of Echocardiography in Hypertrophic Cardiomyopathy

Echocardiographic Features of Hypertrophic Cardiomyopathy

Two-Dimensional and Real-Time Imaging

Obstruction

Systolic Anterior Motion

Echocardiographic and Surgical and Catheter Options for Hypertrophic Obstructive Cardiomyopathy

Role of Treansesophageal Echocardiography in the Surgical Management of Hypertrophic Obstructive Cardiomyopathy

Apical Ballooning Syndrome

Restrictive and Infiltrative Cardiomyopathy

Examples

Echocardiographic Findings

Endomyocardial Fibrosis

Cardiac Amyloidosis

Echocardiographic Findings of Cardiac Amyloidosis

Cardiac Sarcoidosis

Cardiac Hemochromatosis

Chagas Disease

Myocarditis

Transthoracic Echocardiography

ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 Appropriate Use Criteria for Echocardiography ²⁶

Heart Failure (HF) with TTE

Device Evaluation (Including Pacemaker, ICD, or CRT) with TTE

Cardiomyopathies with TTE

ACC/AHA 2003 Guideline Update for the Clinical Application of Echocardiography ²⁷

Recommendations for Echocardiography in Patients with Dyspnea, Edema, or Cardiomyopathy

ACC/AHA 1997 Guidelines for the Clinical Application of Echocardiography ²⁸

Indications for Echocardiography in Patients with Dyspnea, Edema, or Cardiomyopathy

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