Albright Catherine M, Quinn T Alexander, Berberian George, Cabreriza Santos E, Garofalo Cara A, Weinberg Alan D, Dizon Jose M, Spotnitz Henry M
Department of Surgery, Columbia University, New York, New York 10032, USA.
ASAIO J. 2008 Jul-Aug;54(4):335-40. doi: 10.1097/MAT.0b013e31817b5b29.
Optimization of left ventricular pacing site or interventricular pacing delay improves the efficacy of biventricular pacing (BiVP). Cardiac output (CO) based optimization, however, is invasive and slow. QRS duration (QRSd) is noninvasive and responds rapidly. Accordingly, we investigated the utility of QRSd for BiVP optimization in a model of acute right ventricular (RV) pressure overload. In seven anesthetized open-chest pigs, BiVP was implemented with right atrial and RV pacing wires. A 6-electrode array was placed behind the LV. Heart block was established by alcohol ablation. The pulmonary artery was snared to double peak RV pressure. Fifty-four combinations of left ventricular pacing site and interventricular pacing delay were tested in random order over 30-second intervals. QRSd was assessed from electrocardiogram lead II, CO from aortic flow probe, and ventricular function from micromanometers. Comparisons were made with the Pearson's correlation coefficient (r). QRSd narrowing was associated with improved RV function and transseptal synchrony, but correlation with CO was poor. Additionally, QRSd averaged over the last 20 cardiac cycles in each interval was compared with values averaged over successive cardiac cycles following each reprogramming. Seven cardiac cycles after reprogramming, the average r-value went above 0.90 and plateaued. QRSd-based optimization merits further study during BiVP in patients with congestive heart failure.
优化左心室起搏部位或心室间起搏延迟可提高双心室起搏（BiVP）的疗效。然而，基于心输出量（CO）的优化具有侵入性且速度缓慢。QRS波时限（QRSd）是非侵入性的且反应迅速。因此，我们在急性右心室（RV）压力超负荷模型中研究了QRSd在BiVP优化中的效用。在7只麻醉开胸猪中，通过右心房和RV起搏导线进行BiVP。在左心室后方放置一个6电极阵列。通过酒精消融建立心脏传导阻滞。用圈套器阻断肺动脉以使RV压力出现双峰。在30秒的间隔内随机测试54种左心室起搏部位和心室间起搏延迟的组合。从心电图II导联评估QRSd，从主动脉血流探头评估CO，并通过微测压计评估心室功能。采用Pearson相关系数（r）进行比较。QRSd变窄与RV功能改善和跨间隔同步性改善相关，但与CO的相关性较差。此外，将每个间隔内最后20个心动周期的平均QRSd与每次重新编程后连续心动周期的平均值进行比较。重新编程后7个心动周期，平均r值超过0.90并趋于平稳。基于QRSd的优化在充血性心力衰竭患者的BiVP过程中值得进一步研究。
