What would an echocardiogram (echo) show in a patient being considered for restrictive cardiomyopathy?

Echocardiographic Findings in Restrictive Cardiomyopathy

An echocardiogram in a patient being considered for restrictive cardiomyopathy will typically show normal ventricular dimensions and wall thickness with preserved systolic function, markedly dilated atria, and characteristic diastolic filling abnormalities indicating severe diastolic dysfunction. 1

Key Two-Dimensional Echocardiographic Features

• Ventricular chambers: Usually normal in dimension 1
• Ventricular wall thickness: Typically normal 1
• Systolic function: Frequently normal 1
• Atrial chambers: Markedly dilated, reflecting abnormal diastolic compliance of the ventricles 1

Doppler Findings

Mitral Inflow Pattern

• E wave: Increased peak early flow velocity 1
• A wave: Reduced peak late flow velocity 1
• E/A ratio: >2.5 (characteristic of restrictive filling) 1
• Deceleration time: Shortened (<150 msec) 1
• Isovolumic relaxation time: Reduced (<50 msec) 1

Tissue Doppler Imaging

• Mitral annular e' velocity: Abnormally reduced
  • Septal e' <7 cm/sec
  • Lateral e' <10 cm/sec 1, 2
• E/e' ratio: >14 (indicating elevated left ventricular filling pressures) 1, 2

Disease-Specific Findings

Depending on the underlying etiology, additional findings may be present:

• Amyloidosis: Relative apical sparing of longitudinal strain (ratio of 1.0 between average apical strain and average of basal/mid strain) with 93% sensitivity and 82% specificity 1

• Endomyocardial fibrosis: Apical thickening may be present 1

• Sarcoidosis: Ventricular septal thickening and diastolic dysfunction in acute phase; thinning in chronic phase 1

Differential Diagnostic Considerations

• Constrictive pericarditis vs. restrictive cardiomyopathy: Echocardiography can help differentiate these conditions 1
  • In constrictive pericarditis: septal e' is often higher than lateral e' ("annulus reversus") 1
  • In restrictive cardiomyopathy: lateral e' is typically higher than septal e' 1

Clinical Implications

• The presence of grade III diastolic dysfunction (restrictive filling pattern) carries a poor prognosis, with significantly lower survival rates (39%) compared to those with grade I (79%) or normal diastolic function (95%) 2

• Echocardiography is considered a Class I indication (highest recommendation) for establishing the morphologic diagnosis and assessment of hemodynamic status in patients with cardiomyopathies 1

• The combination of two-dimensional and Doppler echocardiographic examination is particularly helpful in patients with restrictive cardiomyopathy and may allow differentiation from constrictive pericarditis 1

Pitfalls to Avoid

• Do not rely solely on the previously described "speckled" or "starry sky" appearance of the myocardium, as this finding is now considered obsolete with modern harmonic imaging techniques 1

• Ensure proper measurement of mitral annular e' velocity by distinguishing it from the biphasic velocity during isovolumic relaxation period 1

• Be aware that restrictive filling patterns can also occur in other conditions like advanced dilated cardiomyopathy, which carries significant prognostic implications 3