Table 2.
Common diagnostic findings of hypertrophic cardiomyopathy, primary restrictive cardiomyopathy, amyloidosis, Fabry disease, and glycogen storage diseases.
| HCM | Primary RCM | Amyloidosis | Fabry Disease | Glycogen Storage Diseases | |
|---|---|---|---|---|---|
| ECG | Increased QRS voltages, ST-T wave changes, pathologic Q waves, LAE, LAD | Normal QRS voltages, ST-T wave changes, atrial fibrillation, intraventricular conduction delay | Low QRS voltages, Q waves and QS complexes, AV blocks and bundle branch blocks | Increased QRS voltages, short PR interval, pathologic Q waves, T wave inversion, sinus bradycardia, AV blocks, bundle branch blocks | Increased QRS voltages, short PR interval, T wave abnormalities, AV blocks |
| Echo | Mild to severe asymmetrical, concentric or apical hypertrophy. LVOT obstruction. Left atrial enlargement. Mitral regurgitation. Diastolic dysfunction (from mild to restrictive physiology) | Nondilated ventricles with normal wall thickness, biatrial enlargement, restrictive filling pattern | Mild concentric left ventricular hypertrophy, right ventricular hypertrophy, thickening of valves and atrial septum, pericardial effusion, “granular” appearance of myocardium, “apical sparing” at global longitudinal strain, restrictive filling pattern | Concentric left ventricular hypertrophy without LVOT obstruction. Left atrial enlargement, valvular thickening, right ventricular hypertrophy. Diastolic dysfunction (from mild to restrictive physiology) | Normal to extreme left ventricular hypertrophy with possible LVOT obstruction, diastolic dysfunction, and restrictive filling pattern |
| CMR | LGE in most hypertrophied regionsHigh native T1 values | - | Diffuse subendocardial LGE (“zebra pattern”), difficulty in nulling the myocardial signal on phase sensitive inversion recovery sequences. High native T1 values | Mid-mural LGE on basal segment of non-hypertrophied inferolateral wall. Low native T1 values | LGE and high T1 values in the advanced stage of the disease |
| EMB | Myocyte hypertrophy, myocardial disarray, interstitial fibrosis | Interstitial fibrosis, myocyte hypertrophy, myocardial disarray | Apple-green birefringence under polarized light microscopy using Congo red staining. Randomly oriented and non-branching fibrils at electron microscopy | Concentric lamellar bodies (degraded products of globotriaosylceramide in the sarcoplasm) | Vacuoles containing glycogen that stain positive with periodic Acid Schiff |
ECG: electrocardiogram; Echo: echocardiogram; CMR: cardiac magnetic resonance; EMB: endomyocardial biopsy; LAE: left atrial enlargement; LAD: left axis deviation; LVOT: left ventricular outflow tract; LGE: late gadolinium enhancement; AV: atrioventricular.