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目的 观察双腔心脏起搏器 (DDD)不同房室延迟 (AVD)时心功能与体表心电图QT间期的变化 ,探讨根据体表心电图QT间期优化AVD的可行性。方法 19例完全性房室传导阻滞植入DDD起搏器患者 ,男10例 ,女 9例 ,平均年龄为 (6 6 .79± 15 .5 2 )岁 ,采用彩色多普勒超声心动图测量不同AVD起搏时心排量 (CO)、左心室收缩末期内径 /舒张末期内径 (LVESd/LVEDd)、左室射血分数 (LVEF)等 ,同时单盲测量不同AVD起搏时 12导联心电图的QT间期。心房起搏频率预设为 75次 /min ,AVD自 90ms起以 30ms步长依次递增至 2 40ms。结果 随着AVD的递增 ,心功能和QT间期随之改善和延长 ,达峰值后又逐渐下降。超声心功能最佳时所对应的AVD与QT间期最大时所对应的AVD的差异无显著性 [分别为 (15 8.80± 13.6 4)ms和 (16 3.30± 30 .41)ms,P >0 .0 5 ];QT间期最大时所对应的心功能各参数与最佳超声心功能各参数相似 [CO分别为(6 .2 9± 1.75 )L/min和 (6 .5 0± 1.5 4)L/min ;LVEF分别为 (6 5 .89± 10 .80 ) %和 (6 7.0 4± 11.19) %;P值均 >0 .0 5 ];QT间期值与CO呈显著正相关性 (r =0 .70 ,P <0 .0 5 )。结论 QT间期随不同AVD时的心功能变化而变化 ,通过测量体表心电图QT间期可进行AVD优化。
Objective To observe the changes of cardiac function and QT interval during different compartment delay (AVD) of dual chamber pacemaker (DDD) and to explore the feasibility of optimizing AVD based on QT interval of body surface electrocardiogram. Methods Nineteen patients with complete atrioventricular block (DDD) pacemaker were enrolled in this study. There were 10 males and 9 females with a mean age of (6.67 ± 15.52) years. Color Doppler echocardiography The cardiac output (CO), left ventricular end-systolic diameter (LVESd / LVEDd) and left ventricular ejection fraction (LVEF) were measured at different AVD pacing, while 12-lead QT interval of electrocardiogram. Atrial pacing frequency is presumed to be 75 beats / min, AVD increasing from 90ms in 30ms steps to 240ms. Results With the increase of AVD, cardiac function and QT interval improved and prolonged, reached a peak and then decreased gradually. There was no significant difference in AVD between corresponding AVD and QT interval when the best echocardiography was best [(15 8.80 ± 13.6 4) ms and (16 3.30 ± 30 .41) ms respectively, P> 0 .0 5]. The parameters of cardiac function corresponding to the largest QT interval were similar to those of the best echocardiographic parameters [CO (6.29 ± 1.75) L / min and (6.5 ± 1.54) ) L / min; LVEF were (65.89 ± 10 .80)% and (6 7.04 ± 11.19)% respectively; P values were all> 0.05]; QT interval was positively correlated with CO (r = 0.70, P <0.05). Conclusions The QT interval varies with the changes of cardiac function at different AVDs. AVD optimization can be performed by measuring the QT interval of the body surface electrocardiogram.