Arrhythmias and Hypertrophic Cardiomyopathy: Unravelling the Connection

Abstract: Hypertrophic cardiomyopathy (HCM) results from gene mutations affecting cardiac sarcomeres and is inherited in an autosomal dominant manner. With a prevalence of 1:200-1:500 in the general population, HCM is characterised by a hypertrophied and non-dilated left ventricle with predominant involvement of the interventricular septum. The myocardium's structural and intracellular factors, combined with triggers such as physical exertion, autonomic dysfunction, and ischemia, can lead to reentry events, and atrial and ventricular arrhythmias, including atrial fibrillation (AF) which is common among HCM patients. To manage the increased risk of mortality arising from congestive heart failure and thromboembolism, in patients with AF long-term anticoagulation and antiarrhythmic drugs are employed. HCM patients may also encounter supraventricular and ventricular arrhythmias, such as nonsustained ventricular tachycardia and ventricular premature beats, which can potentially lead to sudden cardiac death and necessitate treatment with implanted defibrillators. Physicians must comprehensively analyse clinical, anatomical, hemodynamic, rhythmic, functional, and genetic characteristics to identify HCM patients at high risk of sudden death. This article aims to discuss the pathophysiology of arrhythmia in HCM and clinical recommendations for various ventricular and atrial fibrillation including catheter ablation and implantable cardioverter-defibrillator (ICD).