Objectives To investigate the feasibility, advantages and efficacy for implantation of left heart atrial and ventricular epicardial dual chamber pacemaker to treat paediatric complete atrioventricular block.
Methods 11 children with medine age 4.0 years (0.5∼7.6 years) diagnosed as complete atrioventrcular block resisting to drug therapy received implantations of left heart atrial and ventricular epicardial dual chamber pacemakers. Six were male and five female. Temporal or permanent right ventricular pacing were used for all of them before implantation of left heart atrial and ventricular epicardial dual chamber pacemakers. 3 cases showed cardiac dysfunction. Left lateral thoracotomy was performed at 4th intercoastal space along anterior axillary line under general anaesthesia, the pericardium were 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.
Results 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 right ventricular pacing, it decreased to 140 ± 24 ms after implantation of left heart atrial and ventricular epicardial dual chamber pacemaker,significantly lower than right ventrcilar pacing (t = 8.8, P < 0.05). Atrio ventrciular (AV) interval was set at 90ms, PR interval 124 ± 4ms. Echocardiograms performed within 2∼3days after implantation of left heart atrial and ventricular epicardial dual chamber pacemakers showed that for the 3cases 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 ventricular ejection 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 pateins maintain normal during follow up. Pacing status and sensitivity were satisfactory for all these patients during follow up.
Conclusions Implantaion of left heart atrial and ventricular epicardial pacemaker might be considered for children diagnosed as complete atrio ventricular block for whom endocardial pacemaker could not be impalnted, 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.