Children's Heart Centre, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, V Úvalu 84, 150 06 Prague, Czech Republic.
Europace. 2018 Feb 1;20(2):323-328. doi: 10.1093/europace/euw414.
Right bundle branch block is associated with right ventricular (RV) electromechanical dyssynchrony, which may contribute to acute haemodynamic impairment after repair of tetralogy of Fallot (ToF). We sought to evaluate the effects of RV resynchronization on haemodynamics and tissue oxygenation during the first 24 h after surgery.
Arterial pressures, cardiac output, and tissue oxygenation were measured in 28 consecutive patients (median age 10.1 months) during baseline sinus rhythm with right bundle branch block and after RV resynchronization by atrial-triggered RV free wall pacing in complete fusion with spontaneous activation. Studied variables were compared in a crossover design in four 5-min intervals (baseline rhythm and stimulation, 2x each). Resynchronization reduced the QRS complex duration from median 110 to 70 ms (P < 0.001), increased significantly median arterial systolic, mean and pulse pressure, cardiac index, left ventricular maximum +dP/dT and decreased central venous pressure (P < 0.001 for all). Both cerebral and renal oxygenation improved (P < 0.001). Eleven of the 28 patients showed a clinically highly significant resynchronization effect defined as an increase in arterial pulse pressure of ≥ 10%. The q-RV interval (expressed as % of QRS duration) at the RV pacing site during baseline rhythm was the only predictor of resynchronization effect.
RV resynchronization carried short-term improvement of haemodynamics in children early after surgery for ToF and might be a useful non-pharmacologic adjunct to the management of haemodynamically compromised patients. Resynchronization effect was maximized when pacing from area of the latest RV activation.
右束支传导阻滞与右心室（RV）机电不同步相关，这可能导致法洛四联症（ToF）修复后急性血液动力学受损。我们试图评估 RV 再同步对手术后 24 小时内血液动力学和组织氧合的影响。
在窦性心律伴右束支传导阻滞的情况下，连续 28 例患者（中位年龄 10.1 个月）接受了动脉血压、心输出量和组织氧合的测量，随后通过心房触发 RV 游离壁起搏实现 RV 再同步，起搏与自主激活完全融合。在交叉设计中，在四个 5 分钟间隔内（基础节律和刺激，各 2 次）比较了研究变量。再同步使 QRS 复合物持续时间从中位数 110 毫秒缩短至 70 毫秒（P<0.001），显著增加了动脉收缩压、平均压和脉压、心指数、左心室最大+dP/dT，降低了中心静脉压（所有 P<0.001）。脑和肾的氧合均改善（P<0.001）。28 例患者中有 11 例显示出临床高度显著的再同步效应，定义为动脉脉搏压增加≥10%。在基础节律时 RV 起搏部位的 q-RV 间期（以 QRS 持续时间的百分比表示）是再同步效应的唯一预测因子。
RV 再同步在 ToF 手术后早期可短期改善血液动力学，可能是血液动力学受损患者管理的有用非药物辅助手段。当从 RV 最晚激活区域起搏时，再同步效果最佳。
