What are the typical echocardiogram (echo) findings in patients with cardiomyopathy?

Echocardiographic Findings in Cardiomyopathy

Echocardiography is the first-line imaging modality for diagnosing and characterizing all forms of cardiomyopathy, with specific morphologic and functional patterns distinguishing dilated, hypertrophic, and restrictive subtypes. 1

Dilated Cardiomyopathy (DCM)

Primary Morphologic Features

• Ventricular dilation with left ventricular end-diastolic volumes or diameters >2 standard deviations above normal (Z-scores >2 SD) corrected for body surface area and age 1
• Reduced left ventricular ejection fraction (<45%) with global systolic dysfunction 1
• Normal or reduced wall thickness (not hypertrophied) 1
• Four-chamber enlargement with biatrial dilation reflecting elevated filling pressures 1

Functional and Hemodynamic Assessment

• Mitral and tricuspid regurgitation (secondary to annular dilation and leaflet tethering), which serves as a key prognostic marker and should be quantified systematically 1
• Elevated pulmonary pressures assessed by Doppler interrogation of tricuspid regurgitation velocity 1
• Diastolic dysfunction characterized by abnormal ventricular inflow velocity profiles on Doppler 1
• Right ventricular enlargement and dysfunction, which is mandatory to assess as it carries independent prognostic significance 1

Advanced Echocardiographic Parameters

• Global longitudinal strain measurement is recommended at initial evaluation and follow-up, as it detects early systolic dysfunction even when ejection fraction appears preserved 1
• Regional wall motion abnormalities should be assessed to distinguish ischemic from non-ischemic etiology 1
• Intracardiac thrombi detection, particularly in the left ventricular apex (contrast agents may be needed for adequate visualization) 1

Hypertrophic Cardiomyopathy (HCM)

Diagnostic Hallmarks

• Left ventricular hypertrophy with maximum wall thickness as the single most relevant diagnostic parameter; all LV segments from base to apex must be examined at mitral, mid-LV, and apical levels 1
• Asymmetric septal hypertrophy is the most common pattern, though hypertrophy can be localized to any segment including anterolateral wall or apex 1, 2
• Systolic anterior motion (SAM) of the mitral valve occurs in approximately one-third of patients at rest, resulting in left ventricular outflow tract obstruction 1, 2

Obstructive Features

• Dynamic left ventricular outflow tract obstruction assessed at rest and with provocative maneuvers (Valsalva, standing, amyl nitrite) using continuous-wave Doppler 1
• Mitral regurgitation associated with SAM, quantified by Doppler 1
• Septal bounce and septal flash (early systolic septal shortening with inward motion) followed by late systolic stretch, particularly relevant when cardiac resynchronization therapy is considered 1

Functional Assessment

• Diastolic filling abnormalities characterized by impaired relaxation and elevated filling pressures, often preceding systolic dysfunction 1
• Left atrial enlargement reflecting chronic diastolic dysfunction and increased risk of atrial fibrillation 1, 3
• Preserved or hyperdynamic ejection fraction in most cases, though global longitudinal strain may reveal subclinical dysfunction 3, 4

Critical Technical Considerations

Accurate assessment requires meticulous imaging with transducer angulation to avoid lateral resolution errors and foreshortening, particularly for apical HCM; left ventricular opacification with ultrasound contrast agents should be considered when segments are inadequately visualized 1

Restrictive Cardiomyopathy (RCM)

Distinctive Morphologic Pattern

• Normal or near-normal ventricular chamber dimensions without significant dilation 1
• Normal or minimally increased wall thickness (distinguishing it from infiltrative causes with thickening) 1
• Frequently preserved systolic function with normal ejection fraction 1

Characteristic Hemodynamic Features

• Marked biatrial enlargement (often massive), reflecting severely abnormal diastolic compliance of the ventricles 1, 5
• Restrictive filling pattern on Doppler with increased peak early flow velocity (E wave), reduced peak late flow velocity (A wave), shortened deceleration time, and elevated E/e' ratio 1
• Elevated filling pressures with signs of right heart failure including Kussmaul's sign 5

Differential Diagnosis Considerations

Combined two-dimensional and Doppler echocardiography may help differentiate restrictive cardiomyopathy from constrictive pericarditis, though echocardiography alone cannot definitively diagnose constrictive pericarditis without direct pericardial visualization 1, 5. Cardiac CT is the definitive imaging modality for visualizing pericardial thickness and calcification when constrictive pericarditis is suspected 5.

Comprehensive Echocardiographic Protocol

Mandatory Components

• Assessment of left and right ventricular dimensions, systolic function (global and regional), and diastolic function at initial evaluation and follow-up 1
• Valvular function quantification, particularly secondary mitral and tricuspid regurgitation 1
• Pulmonary hypertension assessment via tricuspid regurgitation velocity 1
• Atrial size and geometry measurement 1
• Three-dimensional imaging increasingly recommended for accurate volumetric assessment 1, 4

Serial Monitoring

Echocardiography is useful for serial follow-up to assess disease progression, monitor therapeutic interventions (including cardiotoxic agents like adriamycin), optimize medical management, and detect complications such as thrombus formation 1

Common Pitfalls to Avoid

• Do not dismiss proximal septal thickening as a normal variant without thorough evaluation, especially if septal thickness exceeds 13mm, as this may represent early HCM 3
• Do not rely solely on ejection fraction in HCM, as it may be normal or hyperdynamic despite underlying myocardial dysfunction; global longitudinal strain provides additional prognostic information 3, 4
• Do not overlook diastolic dysfunction assessment, as it often precedes systolic dysfunction and causes symptoms despite preserved ejection fraction 3
• Do not fail to assess for dynamic obstruction during provocative maneuvers in suspected HCM, as latent obstruction may be unmasked 3
• Do not assume "heart failure" without establishing the underlying etiology through comprehensive imaging, as constrictive pericarditis is potentially surgically curable while restrictive cardiomyopathy requires medical management with worse prognosis 5

Complementary Imaging

When echocardiography is inadequate or diagnostic uncertainty exists, cardiac MRI should be obtained for better tissue characterization, detection of fibrosis via late gadolinium enhancement, and comprehensive morphologic assessment 1, 3. Cardiac CT is highly appropriate for excluding coronary artery disease and evaluating pericardial disease 1, 5.