2:1 Atrioventricular Block After Upgrade From DDD to CRT-D

BACKGROUND: A high burden of right ventricular pacing predisposes patients to pacing-induced cardiomyopathy. Cardiac resynchronization therapy with defibrillator (CRT-D) effectively addresses this by delivering biventricular pacing, and a high rate of such pacing is essential for optimal clinical response. CASE SUMMARY: We present a patient with high-grade atrioventricular block who developed 2:1 ventricular pacing after upgrade to CRT-D given pacing-induced cardiomyopathy. The condition was ultimately confirmed to be due to intermittent T-wave oversensing. We successfully restored atrioventricular sequential pacing by adjusting ventricular sensing sensitivity and administering antiarrhythmic medication. DISCUSSION: CRT-D serves as a crucial therapeutic approach for cardiac insufficiency; however, a low biventricular pacing percentage cannot effectively improve cardiac function. Therefore, timely detection and appropriate intervention are essential to ensure adequate biventricular pacing. TAKE-HOME MESSAGES: It is important to perform optimal postprocedural management of CRT-D patients to ensure biventricular pacing. Relevant clinical data should be provided when troubleshooting T-wave oversensing.