Duong Neal C, Yang Zhongping, Iaizzo Paul A
Visible Heart Laboratories, Institute for Engineering in Medicine, University of Minnesota Twin Cities, Department of Surgery, Minneapolis, Minnesota.
Medtronic Inc, Fridley, Minnesota.
Heart Rhythm. 2025 May 8. doi: 10.1016/j.hrthm.2025.04.022.
Bachmann bundle area (BBA) pacing is an attractive alternative to traditional right atrial appendage (RAA) pacing, but its hemodynamic benefits are poorly understood.
The purpose of this study was to evaluate hemodynamic effects of BBA pacing and structural characteristics of the aligned myocytes within BBA.
Five swine were subjected to volume overload by intravenous infusion of 3 L of 0.9% saline solution during 30 minutes. Medtronic 3830 pacing leads were placed in the RAA and BBA. Rates were alternated between the 2 sites at 110, 120, and 130 beats/min, with the acquisition of left ventricular pressure-volume loops. Anatomies were formalin-fixed and treated with a 7.5% iodine solution to delineate contractile myocardium. The specimens underwent a perfused contrast-enhanced micro-computed tomography protocol with iodine to identify soft tissue differences in the tissue.
Our findings revealed atrial synchrony with BBA pacing compared with RAA pacing. BBA pacing reduced average P-wave duration by 27 ms, accompanied by increased left ventricular stroke volume across pacing speeds (23%, 17%, and 15% at 110, 120, and 130 beats/min, respectively). Micro-computed tomography scans depicted orientations of the Bachmann bundle.
Through this study, we have achieved a comprehensive hemodynamic characterization and anatomic reconstruction of Bachmann bundle in a swine model subjected to volume overload. The hemodynamic improvements of BBA pacing relative to RAA pacing underscore the potential of BBA pacing as an alternative site for atrial pacing. This understanding of atrial physiology may inform clinical interventions to optimize pacing strategies.
巴赫曼束区（BBA）起搏是传统右心耳（RAA）起搏的一种有吸引力的替代方法，但其血流动力学益处尚不清楚。
本研究旨在评估BBA起搏的血流动力学效应以及BBA内排列的心肌细胞的结构特征。
5头猪在30分钟内通过静脉输注3L 0.9%盐水溶液使其容量负荷过重。美敦力3830起搏电极分别置于RAA和BBA。两个部位的起搏频率在110、120和130次/分钟之间交替，同时采集左心室压力-容积环。解剖结构用福尔马林固定，并用7.5%碘溶液处理以勾勒收缩心肌。标本采用含碘的灌注对比增强微型计算机断层扫描方案以识别组织中的软组织差异。
我们的研究结果显示，与RAA起搏相比，BBA起搏时心房同步性更好。BBA起搏使平均P波时限缩短27毫秒，同时在不同起搏速度下左心室每搏输出量增加（110、120和130次/分钟时分别增加23%、17%和15%）。微型计算机断层扫描显示了巴赫曼束的走行方向。
通过本研究，我们在容量负荷过重的猪模型中实现了对巴赫曼束的全面血流动力学特征分析和解剖重建。BBA起搏相对于RAA起搏的血流动力学改善突出了BBA起搏作为心房起搏替代部位的潜力。对心房生理学的这种理解可能为优化起搏策略的临床干预提供依据。
