QRS fragmentation in patients with arrhythmogenic right ventricular cardiomyopathy and complete right bundle branch block: a risk stratification.

Background: Patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) and complete right bundle branch block (RBBB) very often have recurrent ventricular tachycardia and develop biventricular heart failure in the follow up, requiring heart transplantation and/or diuretics. In other patients with ARVC/D excluding RBBB, QRS fragmentation in the S wave of right precordial leads identifies patients with recurrent ventricular tachycardia, primary ventricular fibrillation, and recurrent implantable cardioverter defibrillator discharges; QRS fragmentation ≥3 leads characterized patients who died from sudden cardiac death.

Methods: In a cohort of 374 patients with ARVC/D (208 males; mean±SD age 46.5±14.8 years), there were 22 patients with complete RBBB: 17 patients with ARVD/C developed complete RBBB and had biventricular heart failure in a follow up of 4-6 years. In five patients with ARVC/D, complete RBBB was initially evident. In all patients with ARVC/D and RBBB, QRS fragmentation ≥3 of all 12 ECG leads and QRS fragmentation in the S wave of right precordial leads were analysed.

Results: QRS fragmentation ≥3 of all 12 ECG leads and in the S wave of right precordial leads were present in 16/17 patients who developed RBBB and none of the five patients with initial RBBB. In one patient with initial RBBB, QRS fragmentation ≥3 leads was present (r=17.45; p<0.0001).

Conclusions: Patients with recurrent ventricular tachycardia who develop biventricular heart failure requiring heart transplantation and/or diuretics are characterized by QRS fragmentation in the S wave of right precordial leads and ≥3 of all 12 ECG leads. These results are statistically significant. Patients with initial RBBB have an overall benign prognosis.