Impact of atrial septal pacing in left ventricular–only pacing in patients with a first-degree atrioventricular block: A case series

Figures

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  Figure 1. Electrocardiogram and chest radiography of patient in case 1. a: First-degree atrioventricular block (PQ time, 208 ms); the QRS time was 169 ms, complete left bundle branch block was present. b: After cardiac resynchronization therapy (CRT) with left ventricular–only pacing, the QRS time was 132 ms. c: After CRT with biventricular pacing, the QRS time was 166 ms. d, e: Chest radiography before and after CRT, respectively.

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  Figure 2. Atrioventricular time of each right atrium (RA) site of patient in case 1 during cardiac resynchronization therapy implantation. The orange arrow indicates coronary sinus ostium (CSOS). The green arrow indicates the lower near-atrioventricular (AV) node. The yellow arrow indicates the upper near-AV node. When the RA lead was on the CSOS and lower near-AV node, the AV time was >250 ms. When the RA lead was on the upper near-AV node, the AV time was <200 ms.

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  Figure 3. Electrocardiogram (ECG) and chest radiography of patients in cases 2 and 3. a: ECG before cardiac resynchronization therapy (CRT) implantation; first-degree atrioventricular block (PQ time, 250 ms), and a complete left bundle branch block (CLBBB) (QRS time, 130 ms) are presented. b: ECG after CRT implantation; QRS time is shortened to 123 ms. c, d: Chest radiographs before and after CRT, respectively. e: ECG before CRT implantation; first-degree AV block (PQ time, 424 ms) and CLBBB (QRS time, 177 ms) are presented. f: ECG after implantation; QRS time is shortened to 146 ms.