BackgroundThe hemodynamic effects of cardiac resynchronization therapy in patients with left ventricular assist devices (LVADs) are uncharacterized. We aimed to quantify the hemodynamic effects of different ventricular pacing configurations in patients with LVADs, focusing on short‐term changes in load‐independent right ventricular (RV) contractility.Methods and ResultsPatients with LVADs underwent right heart catheterization during spontaneous respiration without sedation and with pressures recorded at end expiration. Right heart catheterization was performed at different pacemaker configurations (biventricular pacing, left ventricular pacing, RV pacing, and unpaced conduction) in a randomly generated sequence with >3 minutes between configuration change and hemodynamic assessment. The right heart catheterization operator was blinded to the sequence. RV maximal change in pressure over time normalized to instantaneous pressure was calculated from digitized hemodynamic waveforms, consistent with a previously validated protocol. Fifteen patients with LVADs who were in sinus rhythm were included. Load‐independent RV contractility, as assessed by RV maximal change in pressure over time normalized to instantaneous pressure, was higher in biventricular pacing compared with unpaced conduction (15.7±7.6 versus 11.0±4.0 s⁻¹; P=0.003). Thermodilution cardiac output was higher in biventricular pacing compared with unpaced conduction (4.48±0.7 versus 4.38±0.8 L/min; P=0.05). There were no significant differences in heart rate, ventricular filling pressures, or atrioventricular valvular regurgitation across all pacing configurations.ConclusionsBiventricular pacing acutely improves load‐independent RV contractility in patients with LVADs. Even in these patients with mechanical left ventricular unloading via LVAD who were relative pacing nonresponders (required LVAD support despite cardiac resynchronization therapy), biventricular pacing was acutely beneficial to RV contractility.

中文翻译：

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心脏再同步治疗与替代起搏策略对左心室辅助装置患者的急性血流动力学影响

背景心脏再同步治疗对左心室辅助装置 (LVAD) 患者的血流动力学影响尚无定论。我们旨在量化不同心室起搏配置对 LVAD 患者的血流动力学影响，重点关注负荷独立右心室 (RV) 收缩力的短期变化。呼气末记录的压力。右心导管插入术在不同的起搏器配置（双心室起搏、左心室起搏、RV 起搏和非起搏传导）下以随机生成的顺序进行，在配置改变和血流动力学评估之间 > 3 分钟。右心导管操作者对序列不知情。从数字化的血流动力学波形计算归一化为瞬时压力的 RV 压力随时间的最大变化，与先前验证的协议一致。包括 15 名处于窦性心律的 LVAD 患者。与非起搏传导相比，双心室起搏中与负荷无关的 RV 收缩力（通过 RV 最大压力随时间的最大变化评估为瞬时压力）更高（15.7±7.6 秒对 11.0±4.0 秒）^-1 ; P = 0.003）。与非起搏传导相比，双心室起搏的热稀释心输出量更高（4.48±0.7 vs 4.38±0.8 L/min；P = 0.05）。在所有起搏配置中，心率、心室充盈压或房室瓣关闭不全无显着差异。结论双心室起搏可显着改善 LVAD 患者的负荷无关 RV 收缩力。即使在这些通过 LVAD 机械性左心室卸荷的患者中，这些患者是相对起搏无反应者（尽管心脏再同步治疗需要 LVAD 支持），双心室起搏对 RV 收缩力也非常有益。