Table 6.
Dilated cardiomyopathy vs. left-dominant arrhythmogenic right ventricular cardiomyopathy
| Dilated cardiomyopathy | Left-dominant ARVC | |
|---|---|---|
| Inheritance | ≤35% (AD) | >50% (AD, AR) |
| Predominant genetic background | Mutations of genes encoding for cytoskeleton, muscular sarcomere, and nuclear envelope proteins | Mutations of genes encoding for desmosomal proteins, PLN, or FLN-C |
| Main clinical manifestations | Heart failure, cardiac arrest, palpitations | Palpitations, syncope, cardiac arrest |
| ECG abnormalities | Left ventricular hypertrophy with a strain pattern of ST-segment; left bundle branch block | Low QRS voltages in limb leads; negative T waves in lateral leads; negative T waves in right precordial leads (biventricular form) |
| Echocardiography and cardiac magnetic resonance imaging findings | Dilated and hypokinetic LV with no or patchy non-ischaemic (mid-myocardial) LGE (septum) | Non-dilated and hypokinetic LV with large amount of non-ischemic (subepicardial) LGE (inferolateral LV wall) |
| Regional wall motion abnormalities (uncommon). | Regional wall motion abnormalities (common). | |
| Systolic LV dysfunction unrelated to the global extent of LGE | Systolic LV dysfunction related to the global extent of LGE | |
| EMB features | Non-specific myocardial abnormalities | Fibrofatty myocardial replacement |
| Types of ventricular arrhythmias | PVBs and NSVT (RBBB pattern); sustained VT(uncommon); VF | PVBs, NSVT, and monomorphic sustained VT (RBBB pattern; both LBBB and RBBB patterns in biventricular form); VF |
| Mechanism of VT | Scar-related or functional re-entry (branch to branch re-entry) | Scar-related re-entry |
| Most common site of VT origin | Intramural septum | Subepicardial infero-lateral LV free wall |
AD, autosomal dominant; AR, autosomal recessive; EMB, endomyocardial biopsy; LBBB, left bundle branch block; LV, left ventricle; NSVT, non-sustained ventricular tachycardia; PVBs, premature ventricular beats; RBBB, right bundle branch block; RV, right ventricle; RVOT, right ventricular outflow tract; TWI, T-wave inversion; VF, ventricular fibrillation; VT, ventricular tachycardia.