New electrocardiographic insights into left bundle branch block and the heart’s electrical position: Case series

Transcatheter aortic valve replacement (TAVR) has become an established therapeutic option for patients with severe aortic stenosis who are at high or intermediate surgical risk.1,2 However, left bundle branch block (LBBB) remains a frequent complication following the procedure, carrying clinical implications such as heart failure, arrhythmias, and increased mortality.3,4 Recent studies propose stricter criteria to define a “true” LBBB, including a QRS duration exceeding 130–140 ms based on sex and the presence of notched morphologies in left-sided leads.