Deciphering the Clinical Heterogeneity and Molecular Underpinnings of Hypertrophic Cardiomyopathy: A Contemporary Synthesis of Genetic, Diagnostic, and Therapeutic Paradigms

Abstract

Hypertrophic cardiomyopathy (HCM) stands as the most prevalent heritable cardiomyopathy, characterized by a complex and heterogeneous phenotype primarily involving unexplained left ventricular hypertrophy in the absence of loading conditions sufficient to account for its magnitude. This monogenic disorder is principally attributed to pathogenic variants in sarcomeric proteins, which instigate a cascade of molecular events culminating in myocyte hypertrophy, disarray, and interstitial fibrosis. The clinical trajectory of HCM is notably variable, ranging from a lifelong asymptomatic course to profound manifestations including heart failure with preserved or reduced ejection fraction, atrial fibrillation, and sudden cardiac death, the latter often linked to ventricular arrhythmias. Contemporary management has evolved beyond a one-size-fits-all approach, now emphasizing a personalized, multimodal strategy. This encompasses sophisticated risk stratification for sudden cardiac death, the judicious application of septal reduction therapies for refractory symptomatic left ventricular outflow tract obstruction, and the nascent era of disease-modifying pharmacological agents. Recent investigations into cardiac sarcomere function and the resulting hypercontractile state have illuminated novel therapeutic targets, offering promising avenues for intervening directly in the underlying pathophysiology. This article seeks to synthesize the current understanding of HCM's genetic architecture, pathophysiological mechanisms, and the expanding armamentarium of diagnostic and therapeutic modalities, thereby providing a comprehensive overview for the modern management of this multifaceted disease.