Unusual electrocardiogram after pacemaker implant in an old gentleman

A hypertensive old man in his 80s with no other known comorbidities presented with exertional fatigue for 3 months and an episode of presyncope 2 days prior to presentation. Bradycardia (heart rate of 45/min) was detected during blood pressure measurement, and a 12-lead ECG revealed 2:1 atrioventricular block with complete right bundle branch block (RBBB) and normal PR interval on conducted beats (figure 1A). Echocardiography demonstrated a structurally normal heart. In view of probable infrahisian atrioventricular block and symptomatic status, he underwent dual-chamber permanent pacemaker implantation. Postpacemaker implantation ECG is shown in figure 1B. …