Diagnosis and management of hypertrophic cardiomyopathy: European vs. American guidelines

Hypertrophic cardiomyopathy (HCM) is the most common genetic heart disease, affecting 1:200 to 1:500 individuals worldwide. Guidelines on the diagnosis and management of HCM have been recently published by the European Society of Cardiology (ESC) and American societies. The ESC guidelines cover a broad range of cardiomyopathies, including HCM, with 119 recommendations, whereas the American guidelines focus exclusively on HCM with 141 specific recommendations. Both guidelines emphasize a comprehensive diagnostic approach, including imaging and genetic testing, but differ in some specific aspects. For example, sudden cardiac death (SCD) risk assessment is a primary point of divergence. The ESC guidelines advocate for the use of a validated Risk-SCD calculator, while the American guidelines rely on specific risk markers for individualized risk evaluation. Management strategies also vary: both guidelines prioritize beta-blockers and calcium channel blockers in patients with resting or provocable left ventricular outflow tract (LVOT) obstruction. If beta-blockers (or verapamil/diltiazem) are ineffective, either disopyramide or the myosin inhibitor mavacamten may be an option with slightly different indications among the two guidelines. Septal reduction therapy is recommended in ESC guidelines for symptomatic patients with significant LVOT gradients, while American guidelines suggest earlier myectomy for certain clinical factors and emphasize shared decision-making. The ESC guidelines recommend sequential atrioventricular pacing and dual-chamber defibrillators for reducing LVOT gradients. The American guidelines focus on genetic testing for risk assessment and suggest periodic cardiac magnetic resonance imaging. This paper provides a detailed comparison of these guidelines, highlighting key differences and areas needing further research and expert debate.