Effectiveness of Bachmann's Bundle Pacing in a Patient With Severe Heart Failure and Refractory Atrial Fibrillation

Figures

• 

  FIGURE 1. Twelve‐lead electrocardiogram before cardiac resynchronization therapy with defibrillator upgrade. Sinus rhythm was present with a heart rate of 71 beats/min. First‐degree atrioventricular block was observed (PR interval, 220 ms). The QRS duration was prolonged to 177 ms, consistent with nonspecific intraventricular conduction delay. The P‐wave duration was 138 ms, indicating intra‐atrial conduction delay.

• 

  FIGURE 2. (A) Comparison of PR intervals during sinus rhythm (SR) and Bachmann's bundle pacing (BBP). The PR interval was 220 ms during sinus rhythm and 205 ms during BBP, indicating no prolongation of atrioventricular conduction with atrial pacing. Unipolar electrogram recorded at the BBP site during SR. A low‐amplitude, fragmented Bachmann's bundle potential (red arrow) was identified at the tip electrode in the middle portion of the P wave. (B) Comparison of twelve‐lead electrocardiograms during intrinsic rhythm and after cardiac resynchronization therapy with defibrillator upgrade with BBP. The QRS duration was shortened to 135 ms. The atrial pacing morphology showed positive P waves in leads I, II, III, and aVF, a biphasic P wave in lead V1, and higher‐amplitude P waves in the inferior leads compared with sinus rhythm. The P‐wave duration was shortened to 117 ms, more than 10 ms shorter than during sinus rhythm, fulfilling the diagnostic criteria for BBP. BBP, Bachmann's bundle pacing; CRT‐D, cardiac resynchronization therapy with defibrillator; SR, sinus rhythm.

• 

  FIGURE 3. Lead positions after cardiac resynchronization therapy with defibrillator upgrade. The atrial lead was positioned at the high atrial septum, and the left ventricular (LV) lead was positioned in the anterolateral coronary sinus branch. The LV mid site (LV 2–3) showed the greatest electrical delay, with a QLV of 100 ms, and was selected as the LV pacing site (yellow arrow). LAO, left anterior oblique; LV, left ventricular; RAO, right anterior oblique.

• 

  FIGURE 4. (A) Atrial fibrillation (AF) burden before and after cardiac resynchronization therapy with defibrillator (CRT‐D) upgrade. The vertical axis represents AF duration per day, and the horizontal axis represents time with the CRT‐D upgrade procedure defined as Month 0. Although AF control remained difficult despite AF ablation (black arrow), AF control improved markedly after CRT‐D upgrade with Bachmann's bundle pacing (BBP) (red arrow). (B) During sinus bradycardia (heart rate, 45 beats/min), reservoir strain was 12.3% and contractile strain was 5.7%, indicating severely impaired atrial function. During BBP (heart rate, 50 beats/min), reservoir strain improved to 18.5% and contractile strain to 11.5%, demonstrating improved left atrial contractile function. AF, atrial fibrillation; BBP, Bachmann's bundle pacing; CRT‐D, cardiac resynchronization therapy with defibrillator; HR, heart rate; Sct, contractile strain; Sr, reservoir strain; SR, sinus rhythm.