Fragmented QRS as a candidate marker for high-risk assessment in hypertrophic cardiomyopathy.

Abstract

The relationship between a fragmented QRS complex (fQRS) on 12-lead ECG and fatal arrhythmic events in hypertrophic cardiomyopathy (HCM) remains unclear. The purpose of this study was to investigate whether fQRS is associated with ventricular arrhythmic events (VAEs) in HCM patients. Of an initial cohort of 273 patients (57% male, mean age 55 years) diagnosed with HCM, 167 patients were included and divided into 2 groups: those with fQRS (n = 67) and those without fQRS (n = 100). fQRS was defined as notching of the R or S wave in 2 contiguous leads. VAEs were defined as nonsustained or sustained ventricular tachycardia (VT) or sudden cardiac death (SCD). Major arrhythmic events (MAEs) were sustained VT or SCD. During mean follow-up of 6.3 years, univariate analysis showed that fQRS was significantly associated with increased VAEs (unadjusted hazard ratio [HR] 6.17, 95% confidence interval [CI] 2.46-15.49, P < .001) and MAEs (unadjusted HR 5.12, 95% CI 1.38-19.01, P = .014). Multivariate analysis revealed that fQRS was a strong independent predictor of VAEs (adjusted HR 6.28, 95% CI 2.49-15.84, P < .001) and MAEs (adjusted HR 6.04, 95% CI 1.49-24.39, P = .011). fQRS in the inferior leads was most closely related to MAEs compared to fQRS in other myocardial territories, and its inclusion in a risk calculator for mortality in HCM patients increased the positive predictive value from 8% to 25% in low-risk patients. Presence of an fQRS may be a good candidate marker for prediction of VAE in patients with HCM.