Overview of Arrhythmogenic Cardiomyopathies

Any cardiac disorder can produce cardiac and systemic factors that predispose to arrhythmias, including bradyarrhythmias, atrial and ventricular tachyarrhythmias, and sudden death. However, some cardiac disorders are particularly prone to do so and are referred to as arrhythmogenic cardiac disorders or, when associated with ventricular scarring, arrhythmogenic cardiomyopathies. The term arrhythmogenic cardiomyopathy is used both broadly to encompass nonischemic, scar-related cardiomyopathies, and more narrowly to refer specifically to arrhythmogenic right, left, and biventricular cardiomyopathy. Examples of arrhythmogenic cardiomyopathies using the broader definition include:

• Arrhythmogenic right ventricular cardiomyopathy and its variants

• Lamin A/C cardiomyopathies

• Non-compaction cardiomyopathy

• Cardiac sarcoidosis

• Hypertrophic cardiomyopathy

Most of these disorders have genetic causes, which are typically inherited but are sometimes acquired conditions. These arrhythmogenic cardiomyopathies account for approximately 12% 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 exercise 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, ambulatory electrocardiographic monitoring, and cardiac MRI. If a specific form of arrhythmogenic cardiomyopathy is suspected, other investigations may be indicated, including signal-averaged ECG, exercise testing, chest CT, electrophysiologic study, angiography, and/or endomyocardial biopsy. Genetic testing is usually performed 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 that is felt to be causative is found.

Management depends on the cause of the cardiomyopathy and the specific rhythm disturbance, but it 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.