Sudden Cardiac Death and Ventricular Arrhythmias in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac condition, with an associated increased risk of ventricular arrhythmias and sudden cardiac death. Young and asymptomatic patients, including professional athletes, are not spared this risk. Implantable cardiac defibrillators (ICDs) are highly effective in terminating malignant ventricular arrhythmias in this group, but they are associated with significant morbidity, such as inappropriate shocks and device complications. Accurate prognostication to guide ICD implantation is therefore essential. The interplay of traditional risk factors, risk modifiers and predictive models creates a complex decision-making environment for the HCM clinician. Risk stratifying tools are expanding with improved understanding of advanced imaging modalities, such as late gadolinium enhancement on cardiac magnetic resonance imaging (cMRI). Once the decision to implant a defibrillator is reached, the choice of device and programming in HCM is unique and should take into account disease substrate and younger age of patients.