Abstract

Introduction

Pacemaker implantation (PI) for children has a series of singularities distinguishing this procedure from those for adults and until now its outcomes are far from satisfactory. Practically always the indications for such operations are life saving and determined by complete atrioventricular block (AVB) after cardiopulmonary bypass (CPB) surgery or congenital AVB or sick sinus syndrom or all of them associated with congenital heart disease. We tried to develop methods of choice to take preventive measures, to optimize the results and review the consequences of operations on the basis of studying its outcomes and hemodynamic changes.

Methods

Before November 1997 PI was performed in 20 children between 7 - 14 years of age. The average age at the moment of the first operation was 10,5 years. There were 13 boys and 7 girls. All patients were divided into two groups according to the ethiologic factor of their pathology: The first group included 10 children with congenital AVB with syncope (4); AVB Mobitz type II with syncope, sinoatrial block (SB), carotide sinus syndrome (CSS), binodal syndrome and tachycardia from atrioventricular junction in one patient. We have included in the same group a child with combination of a patent ductus arteriosus with congenital AVB and syncope. The second group included 10 patients with dysrhythmias after cardiopulmonary bypass surgery because of congenital heart diseases: Tetrology of Fallot (2), ventricular septal defect (VSD) with pulmonal stenosis (2), partial atrioventricular communication (1), VSD (3) and atrial septal defect (2). In these patients AVB with syncope (7), AVB Mobitz type II (2) and sinus bradycardia (1) has developed intraoperatively or soon after operation. Before and after operation all patients underwent chest X-ray, ECG, ultrasound examination by Appogee CX interspec. End diastolic volume, end systolic volume, stroke volume, ejection fraction and cardiac index were determined. Transesophageal and invasive electrophysiologic examination have been also done using Prucka Engineering. Follow-up period was from 2 months till 8 years. All patients were operated on. In 11 patients one operation was performed, two - in 6 and three or more operations in 3 patients. Types of pacemakers are represented in table 1.

Results and Comments

Indications for operation in the first patients’ group were syncope or haemodynamic falling attacks. VVI, VVIR or AAI pacing mode has been applied for those patients. Atrial single- chamber stimulation has been applied for children with intact atrioventricular conduction. We considered this stimulation mode as justified when sinocarotid, Ashner and Valsalva tests have not provoked atrioventricular conduction disturbances during transesophageal stimulation of the left atria. Indication for operation in patients’ group two was postoperative AVB resistant to conservative treatment including temporary stimulation during 12 days after CPB operation. Such conduction disturbances manifested with ventricular asystole or bradycardia less then 60 beats per minute. We applied VVI and VVIR stimulation mode in those children.

There were 10 (50 %) patients with complications after PI. Aging related shortening of the electrode in 3 patients, decubitus of pacemaker’s pocket in 3 patients, fracture of the electrode, exit-block, diaphragm stimulation and exhaustion of the battery in one patient. For these complications children were reoperated on. Replacement of the total pacing systems or their parts has been performed.

This significant number of complications after PI is probably due to age related characteristics of the procedure. Within the age from 7 to 14 years the height and the weight of a child increases sometimes twice. Under these circumstances, the exact determination of a correct electrode’s length is too difficult and children have been reoperated on because of shortness of the endocardial lead. The creation of a primary wide electrode’s loop causes a threat of electrode’s dislocation or can break during mechanical work of the heart. Other problems are rather weak developed muscles, thin subcutaneous and interfascial fatty tissue in children, that together with high motive activity provide a decubitus of the generator’s pocket. The large size of domestic pacemakers may cause a decubitus of the generator’s pocket and migration of the pacemaker itself. The use of foreing products is limited because of their high price. PI under the musculus rectus abdominis is discussible because of high risk of pacemaker migration into the abdominal cavity.

Conclusions

The indications of PI for children are life saving. An individual selection of pacemakers’ type and stimulation mode, recognition of age related singularities, the choice of PI side and careful observation of the patients are methods of choice to prevent complications and optimize the outcome.

Table 1