Overview of Arrhythmogenic Cardiomyopathies

Although any dilated or hypertrophic cardiomyopathy (see Overview of Cardiomyopathies) can produce cardiac and systemic factors that predispose to a number of different arrhythmias, including bradyarrhythmias, atrial and ventricular tachyarrhythmias, and sudden death, certain cardiomyopathies are particularly prone to do so. These are referred to as arrhythmogenic cardiomyopathies and include

• Arrhythmogenic right ventricular cardiomyopathy

• Lamin A/C cardiomyopathies

• Non-compaction cardiomyopathy

• Cardiac sarcoidosis

• Hypertrophic cardiomyopathy

Some of these disorders have genetic causes, which are typically inherited but are sometimes acquired conditions. These arrhythmogenic cardiomyopathies account for approximately 20% of sudden cardiac deaths in non-athletes ≤ 35 years of age (1).

The signs and symptoms of the arrhythmogenic cardiomyopathies are not specific and may include those of heart failure itself, along with those of bradyarrhythmias and tachyarrhythmias. Heart failure manifestations include exertion intolerance secondary to dyspnea and/or fatigue, orthopnea, and/or peripheral edema. Arrhythmias may cause palpitations, light headedness, syncope, cardiac arrest, and sudden death.

Evaluation typically includes family history, ECG, chest radiography, echocardiography, and cardiac MRI. If a specific form of arrhythmogenic cardiomyopathy is suspected, other investigations may be indicated, including signal-averaged ECG, exercise testing, ambulatory electrocardiographic monitoring, chest CT, electrophysiologic study, angiography, and/or endomyocardial biopsy. Genetic testing is usually done when a genetic cause is suspected; first-degree relatives of patients with a confirmed disorder should be screened clinically and with genetic testing when a specific mutation is found.

Management depends on the cause of the cardiomyopathy and the specific rhythm disturbance, but typically includes standard measures for heart failure (sometimes including cardiac transplantation), antiarrhythmic medications, and sometimes an implantable cardioverter-defibrillator (ICD) and/or catheter ablation of the arrhythmogenic substrate.