Arq Bras Cardiol. 2013 Nov;101(5):410-7. doi: 10.5935/abc.20130189. Epub 2013 Sep 24.
Chronic right ventricular pacing (RVP) induces a dyssynchronous contraction pattern,producing interventricular and intraventricular asynchrony. Many studies have shown the relationship of RVP with impaired left ventricular (LV) form and function.
The aim of this study was to evaluate LV synchrony and function in pediatric patients receiving RVP in comparison with those receiving LV pacing (LVP).
LV systolic and diastolic function and synchrony were evaluated in 80 pediatric patients with either nonsurgical or postsurgical complete atrioventricular block, with pacing from either the RV endocardium (n = 40) or the LV epicardium (n = 40). Echocardiographic data obtained before pacemaker implantation, immediately after it, and at the end of a mean follow-up of 6.8 years were analyzed.
LV diastolic function did not change in any patient during follow-up. LV systolic function was preserved in patients with LVP. However, in children with RVP the shortening fraction and ejection fraction decreased from medians of 41% ± 2.6% and 70% ± 6.9% before implantation to 32% ± 4.2% and 64% ± 2.5% (p < 0.0001 and p < 0.0001), respectively, at final follow-up. Interventricular mechanical delay was significantly larger with RVP (66 ± 13 ms) than with LVP (20 ± 8 ms). Similarly, the following parameters were significantly different in the two groups: LV mechanical delay (RVP: 69 ± 6 ms, LVP: 30 ± 11 ms, p < 0.0001); septal to lateral wall motion delay (RVP: 75 ± 19 ms, LVP: 42 ± 10 ms, p < 0.0001); and, septal to posterior wall motion delay (RVP: 127 ± 33 ms, LVP: 58 ± 17 ms, p < 0.0001).
Compared with RV endocardium, LV epicardium is an optimal site for pacing to preserve cardiac synchrony and function.
慢性右心室起搏（RVP）会引起收缩不同步，导致室间和室内不同步。许多研究表明，RVP 与左心室（LV）形态和功能受损之间存在关系。
本研究旨在评估接受 RVP 起搏与接受 LV 起搏（LVP）的儿科患者的 LV 同步性和功能。
对 80 例非手术或术后完全性房室传导阻滞的儿科患者进行评估，这些患者分别接受 RV 心内膜（n = 40）或 LV 心外膜（n = 40）起搏。在植入起搏器前、植入后即刻以及平均 6.8 年的随访结束时，分析超声心动图数据。
在随访期间，任何患者的 LV 舒张功能均未发生变化。接受 LVP 的患者 LV 收缩功能得到保留。然而，接受 RVP 的患儿的缩短分数和射血分数从植入前的中位数 41%±2.6%和 70%±6.9%分别下降至最终随访时的 32%±4.2%和 64%±2.5%（p<0.0001 和 p<0.0001）。RVP 组的室间机械延迟明显大于 LVP 组（66±13 ms 比 20±8 ms）。同样，两组之间的以下参数存在显著差异：LV 机械延迟（RVP：69±6 ms，LVP：30±11 ms，p<0.0001）；室间隔至侧壁运动延迟（RVP：75±19 ms，LVP：42±10 ms，p<0.0001）；以及室间隔至后壁运动延迟（RVP：127±33 ms，LVP：58±17 ms，p<0.0001）。
与 RV 心内膜相比，LV 心外膜是维持心脏同步性和功能的最佳起搏部位。
