Electrocardiographic findings in leads V3R to V5R in patients with a slurred or notched S wave in lead V

Background Right bundle branch block （RBBB） may present as slurred or notched S wave in lead V1. However, slurred or notched S wave may also represent slow conduction in the myocardium. Methods We retrospectively analyzed the QRS patterns in leads VgR to V5R in 7 patients with a slurred or notched S wave in lead V1. Results In the leads V3R to VSR, 6 patients showed incomplete or complete RBBB and 1 patient slurred or notched S wave. Conclusions In the majority of ECGs in a small patient series with slurred or notched S wave in lead V1, QRS morphology indicating incomplete or complete RBBB was present in leads V3R to VSR. A finding of fragmented QRS in these leads may indicate slow conduction in the myocardium.