First Pediatric Application of Bachmann's Bundle Pacing and Left Bundle Branch Area Pacing for Bi‐Physiologic Conduction System Pacing

Figures

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  Figure 1. Electrophysiological mapping and pacing of Bachmann's bundle (BB). (a and b) Right (RAO) and left (LAO) anterior oblique fluoroscopic views showing contrast delineation of the superior vena cava–right atrial (SVC‐RA) junction. Mapping the high atrial septum using a 6Fr deflectable quadripolar catheter at the site with BB. (c) Intracardiac electrogram (EGM) recorded at the target site. The tracing identifies complex fractionated potentials (red arrow) timing well within the surface P‐wave, confirming the BB site prior to lead fixation. The magnified view (red box) highlights these characteristic low‐amplitude, fractionated BB potentials occurring approximately 20 ms after the onset of the surface P‐wave. (d) Fluoroscopy with contrast and TEE confirming the Medtronic 3830 lead tip position at the high atrial septum/SVC‐RA junction. (e) Paced ECG demonstrating successful electrical resynchronization. Note the isoelectric latency between the pacing stimulus and the onset of the P‐wave deflection. Pacing from the BB site significantly shortens the PWD to 66 ms compared to the intrinsic 122 ms.

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  Figure 2. Final procedural outcome. (a) Postoperative CXR showing the transvenous dual‐chamber system. Note the U‐shaped lead slack in the RA. (b) Final DDD pacing ECG showing a narrow QRS with an rSR' pattern in V1 (confirming LBBAP) and a narrowed P‐wave morphology. Deep T‐wave inversions in V1–V4 were observed, consistent with cardiac memory commonly associated with LBBAP.

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  Figure 3. Assessment of mechanical atrial synchrony using speckle tracking echocardiography. Comparison of longitudinal strain and strain rate curves during intrinsic sinus rhythm (a and b) versus BB pacing (c and d). (a and b) The average longitudinal strain was −17.25% for the left atrium (LA) and −18.25% for the right atrium (RA). The interatrial conduction delay (difference in time to negative peak [TTNP] strain rate between LA and RA) was 53 ms. (c and d) BB pacing resulted in improved mechanical resynchronization. The interatrial conduction delay was reduced to 40 ms. LA and RA longitudinal strain were similar to sinus, measuring −19.65% and −15.25% respectively. GS, global strain; LA, left atrium; RA, right atrium; TTNP, time to negative peak.