Electromechanical delay in right bundle branch block: suggestive predictor of right ventricular systolic function

Abstract

Background: RV dysfunction is a powerful predictor of prognosis in cardiopulmonary diseases. Recognition of RV dysfunction is clinically important, because impairment of RV systolic function is independently associated with adverse outcomes. ECG may serve as a simple tool for detection of underlying RV dysfunction in patients with RBBB.Methods: Patients with complete RBBB (n=225) who underwent ECG and Echocardiography were screened from May 2017 to Jan 2019. Demographic, comorbidity data, ECGs and echocardiography were obtained. QRS and R’ duration was measured. RV dysfunction was defined by RV FAC<35%, TAPSE<17 and RV TEI Index>0.54.Results: As compared to normal RV function, patients with RV dysfunction showed reduced TAPSE and RV FAC and increased RV systolic pressure, RV dimension and RV myocardial performance index (all p<0.05). The R′ duration was significantly associated with RV FAC (r=-0.615, p<0.001), RV systolic pressure (r=0.138, p=0.008), RV dimension (r=0.189, p<0.001) and RV Myocardial Performance Index (r=0.190, p<0.001). On ROC curve analysis, V1R′ duration>100 ms was associated with RV dysfunction with 40% sensitivity and 90% specificity (AUC: 0.883; p<0.001). Lead V1 QRS duration>137 ms and the ratio of R′:QRS duration was also useful for predicting RV dysfunction (all p<0.001). Conclusions: In patient with RBBB, the electromechanical delay has a correlation with RV systolic dysfunction. R′ prolongation in lead V1 can be a useful marker to determine the presence of underlying RV dysfunction as a non-expensive tool.