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.