Vanderheyden Marc, De Backer Tine, Rivero-Ayerza Maximo, Geelen Peter, Bartunek Jozef, Verstreken Sofie, De Zutter Mark, Goethals Marc
Cardiovascular Center, Onze Lieve Vrouw Ziekenhuis, Aalst, Belgium.
Heart Rhythm. 2005 Oct;2(10):1066-72. doi: 10.1016/j.hrthm.2005.07.016.
The aim of cardiac resynchronization therapy is correction of left ventricular (LV) dyssynchrony. However, little is known about the optimal timing of LV and right ventricular (RV) stimulation.
The purpose of this study was to evaluate the acute hemodynamic effects of biventricular pacing, using a range of interventricular delays in patients with advanced heart failure.
Twenty patients with dilated ischemic (n = 12) and idiopathic (n = 8) cardiomyopathy (age 66 +/- 6 years, New York Heart Association class III-IV, LV end-diastolic diameter >55 mm, ejection fraction 22% +/- 18%, and QRS 200 +/- 32 ms) were implanted with a biventricular resynchronization device with sequential RV and LV timing (VV) capabilities. Tissue Doppler echocardiographic parameters were measured during sinus rhythm before implantation and following an optimal AV interval with both simultaneous and sequential biventricular pacing. The interventricular interval was modified by advancing the LV stimulus (LV first) or RV stimulus (RV first) up to 60 ms. For each stimulation protocol, standard echocardiographic Doppler and tissue Doppler imaging (TDI) echo were used to measure the LV outflow tract velocity-time integral, LV filling time, intraventricular delay, and interventricular delay.
The highest velocity-time integral was found in 12 patients with LV first stimulation, 5 patients with RV first stimulation, and 3 patients with simultaneous biventricular activation. Compared with simultaneous biventricular pacing, the optimized sequential biventricular pacing significantly increased the velocity-time integral (P <.001) and LV filling time (P = .001) and decreased interventricular delay (P = .013) and intraventricular delay (P = .010). The optimal VV interval could not be predicted by any clinical nor echocardiographic parameter. At 6-month follow-up, the incidence of nonresponders was 10%.
Optimal timing of the interventricular interval results in prolongation of the LV filling time, reduction of interventricular asynchrony, and an increase in stroke volume. In patients with advanced heart failure undergoing cardiac resynchronization therapy, LV hemodynamics may be further improved by optimizing LV-RV delay.
心脏再同步治疗的目的是纠正左心室（LV）不同步。然而，关于左心室和右心室（RV）刺激的最佳时机知之甚少。
本研究的目的是评估在晚期心力衰竭患者中使用一系列心室间延迟进行双心室起搏的急性血流动力学效应。
20例扩张型缺血性心肌病（n = 12）和特发性心肌病（n = 8）患者（年龄66±6岁，纽约心脏协会III-IV级，左心室舒张末期直径>55 mm，射血分数22%±18%，QRS波时限200±32 ms）植入具有顺序右心室和左心室起搏功能（VV）的双心室再同步装置。在植入前窦性心律期间以及在优化的房室间期后同时和顺序双心室起搏时测量组织多普勒超声心动图参数。通过提前左心室刺激（左心室优先）或右心室刺激（右心室优先）最多60 ms来改变心室间期。对于每种刺激方案，使用标准超声心动图多普勒和组织多普勒成像（TDI）超声测量左心室流出道速度时间积分、左心室充盈时间、心室内延迟和心室间延迟。
12例左心室优先刺激患者、5例右心室优先刺激患者和3例双心室同时激活患者的速度时间积分最高。与双心室同时起搏相比，优化的顺序双心室起搏显著增加了速度时间积分（P <.001）和左心室充盈时间（P =.001），并减少了心室间延迟（P =.013）和心室内延迟（P =.010）。任何临床或超声心动图参数均无法预测最佳VV间期。在6个月的随访中，无反应者的发生率为10%。
心室间期的最佳时机可导致左心室充盈时间延长、心室间不同步减少和每搏量增加。在接受心脏再同步治疗的晚期心力衰竭患者中，优化左心室-右心室延迟可能会进一步改善左心室血流动力学。
