Differential diagnosis between ALVC and DCM
| ALVC | DCM | |
| Predominant genetic background | Mutations of genes encoding for desmosomal proteins, phospholamban and filamin C. | Mutations of genes encoding for cytoskeleton, muscular sarcomere and nuclear envelope proteins. |
| Main clinical manifestations | Palpitations, syncope and cardiac arrest. | Heart failure and cardiac arrest. |
| ECG abnormalities | Low QRS voltages in limb leads; negative T-waves in (infero-)lateral leads. | Left ventricular hypertrophy with a strain pattern of ST segment; LBBB. |
| Echocardiography and CMR imaging features | Non-dilated and hypokinetic LV with a large amount of non-ischaemic (subepicardial) LGE (inferolateral LV wall). Regional wall motion abnormalities (common). Systolic LV dysfunction related to the global extent of LGE. | Dilated and hypokinetic LV with no or patchy non-ischaemic (mid-myocardial) LGE (septum). Regional wall motion abnormalities (uncommon). Systolic LV dysfunction unrelated to the global extent of LGE. |
| Histopathological features | Fibrofatty myocardial replacement. | Non-specific myocardial abnormalities±fibrosis. |
| Types of ventricular arrhythmias | PVBs, NSVT and monomorphic sustained VT (RBBB pattern; both LBBB and RBBB patterns in biventricular form); VF. | PVBs and NSVT (RBBB pattern); uncommon sustained VT; VF. |
| Mechanism of VT | Scar-related re-entry. | Scar-related or functional re-entry (branch to branch re-entry). |
| Most common site of VT origin | Subepicardial inferolateral LV free wall. | Intramural septum. |
ALVC, arrhythmogenic left ventricular cardiomyopathy; CMR, cardiac magnetic resonance; DCM, dilated cardiomyopathy; LBBB, left bundle branch block; LGE, late gadolinium enhancement; LV, left ventricle; NSVT, non sustained ventricular tachycardia; PVBs, premature ventricular beats; RBBB, right bundle branch block; VF, ventricular fibrillation; VT, ventricular tachycardia.