The quest for perfection: the contribution of the electrocardiogram to the prevention of sudden death in hypertrophic cardiomyopathy

Abstract

Haghjoo et al. 1 report a retrospective electrocardiographic study investigating the prognostic value of the 12-lead electrocardiogram (ECG) in 173 patients with hypertrophic cardiomyopathy (HCM). During a follow-up period of 50 months, 6% of the study group experienced the composite endpoint of sudden cardiac death (SCD), aborted SCD, or appropriate internal cardioverter defibrillator (ICD) shock. Univariable analysis confirmed the association of conventional risk markers such as non-sustained ventricular tachycardia, severe left ventricular (LV) hypertrophy, and a history of unexplained syncope with the composite endpoint, but also identified ST-segment depression in the high lateral leads (I and aVL) as a predictor of SCD. When the relative contribution of each predictor to the composite endpoint was examined with multivariable analysis, only ST-segment depression in the high lateral leads and syncope emerged as independent predictors. In spite of its still powerful reputation as a disease typified by premature death, most contemporary survival studies indicate that HCM is associated with a low annual risk of SCD. Nevertheless, it is clear that the susceptibility to ventricular arrhythmia varies substantially between individuals and so risk stratification remains central to clinical management. Patients with HCM develop ventricular arrhythmia for many reasons. Myocardial hypertrophy causes dispersion of repolarization and refractoriness making the myocardium vulnerable to triggered arrhythmias while the accompanying disarray and fibrosis create areas of conduction block … *Corresponding author. Tel: +44 2075728888, Fax: +44 2075738838, Email: perry.elliott{at}ucl.ac.uk