儿童经胸植入左房左室心外膜永久双腔起搏器疗效探讨

Left atrial and ventricular epicardiai dual chamber pacing through a left lateral thoracotomy to treat pediatric complete atrioventricular block

目的探讨植入左房左室心外膜永久双腔起搏器治疗儿童完全性房室传导阻滞的可行性、优越性及疗效。方法本组11例完全性房室传导阻滞患儿，中位年龄4．0岁（0．5—7．6岁），其中男6例，女5例，药物治疗均无效，均植入心外膜左房左室永久双腔起搏器。本组术前均为右室临时或永久起搏方式，3例存在心功能不全。经左侧第4肋间腋前线开胸，将心外膜起搏电极固定于左心耳及左室心外膜，于腹部左季肋下制作囊袋置入脉冲发生器，经皮下隧道连接起搏电极导线。术后随访心功能变化、起搏参数和功能、心电图参数。结果11例患儿均成功植入左房左室心外膜永久双腔起搏器。左室起搏QRS问期较术前右室起搏QRS间期明显缩短[（140±24）ms7）S．（180±33）ms，t=8．8，P〈0．05]。3例右室或右房右室起搏方式存在心功能受损患儿，植入左房左室心外膜起搏器随访2～14个月，左室射血分数逐渐恢复正常（65％±8％），与植入前左室射血分数（30％±15％）相比差异有统计学意义（t=5．6，P〈0．05）。其余8例患儿随访期间心脏大小及左室收缩功能保持在正常范围。全部患儿随访显示起搏及感知功能良好。结论在因条件限制需植入心外膜永久心脏起搏器的房室传导阻滞患儿，可选择左房左室心外膜起搏，以尽可能小的创伤、最大限度保护患儿的心脏功能．有效避免或逆转起搏器综合征．可作为植入心脏起搏器心外膜电极首选及常规部位。

Objective To investigate the feasibility, advantages and efficacy of implantation of left atrial and ventricular epicardial dual chamber pacemaker to treat pediatric complete atrioventricular block. Method Eleven children with median age 4. 0 years （0. 5±7.6 years） diagnosed as complete atrioventricular block resisting to drug therapy received implantations of left atrial and ventricular epicardial dual chamber pacemakers. Six were male and five female. Temporal or permanent fight ventricular pacing was used for all of them before implantation of left atrial and ventricular epicardial dual chamber pacemakers. Three cases showed cardiac dysfunction. Left lateral thoracotomy was performed at 4th intercoastal space along anterior axillary line under general anesthesia, the pericardium was incised vertically anterior to the phrenic nerve, two pacing leads were individually located at left atrial appendage and left ventricular lateral wall. After all the parameters were detected to be satisfactory, a pouch was made at left abdomen under coastal margin. Dual chamber pacemaker was connected with pacing leads through subcutaneous tunnels. The sizes of heart chambers, cardiac functions, parameters of pacemaker, sensitivity, pacing status, PR interval and QRS interval were closely followed up post-operatively. Result Implantations of pacemakers were successful for all of the patients with no complications associated with operations. Preoperative electrocardiograms showed QRS interval （180 ± 33 ）ms under fight ventricular pacing, it decreased to （140 ± 24）ms after implantation of left atria/ and ventricular epicardial dual chamber pacemaker, significantly lower than right ventricular pacing（ t = 8.8, P 〈 0.05 ）. Atrioventricular （AV） interval was set at 90 ms, PR interval （ 124 ± 4 ） ms. Echocardiograms performed within 2 -3 days after implantation of left atrial and ventricular epicardial dual chamber pacemakers showed that for the 3 cases who were previously under right atrial and right ventricular dual chamber pacing presenting cardiac dysfunction, their left ventricular diastolic diameter （LVDd） decreased from （46. 3 ± 12. 5） （32. 0±55.0） ms to （44. 7 ± 12. 0） （31.0 - 53.0） mm and left ventricularejection fraction（LVEF） increased from 30% ± 15% （ 18% -47% ）to 44% ±18% （33% -65% ）. During 2- 14 months＇ follow up, LVEF increased progressively which became significantly higher than before （65%-8% vs. 30% - 15%, t = 5.6,P 〈 0.05）. Cardiac chamber sizes and left ventricular systolic function for the other 8 patients maintain normal during follow up. Pacing status and sensitivity were satisfactory for all these patients during follow up. Conclusion Implantation of left atrial and ventricular epicardial pacemaker might be considered for children diagnosed as complete atrioventricular block for whom endocardial pacemaker could not be implanted, due to its utmost protection for cardiac function with minimal injury and its ability to prevent or reverse pacemaker syndrome. Left atrial and left ventricular epicardium should be regarded as the first-choice and routine locations for epicardial pacing.