Heart block in children

Expanding ventricular shunts for hydrocephalus in infancy and childhood

Expanding, adult-length catheters to accommodate continuing somatic growth have been implanted in the course of shunts, either to the heart or peritoneum, in 12 hydrocephalic infants and young children. Three of four patients with direct cardiac shunts are doing well 22, 28 and 30 months following primary shunt operations, and five of eight patients with ventriculo-peritoneal shunts are progressing favourably four to 10 months after shunt placement. While no claims can be made for long-term benefits, the preliminary results of these procedures are encouraging.

Pacemakers in children: an update

This report reviews recent pacemaker technological advances as they apply to infants, children, and adolescents. Indications for pacemaker implantation in children have evolved since the 1984 Joint Task Force Guidelines. Recent data show that pacemaker implantation should be strongly considered in patients who have (1) asymptomatic congenital complete AV block with a mean heart rate less than 50 beats/min or other evidence of junctional instability; (2) congenital AV block with long QT interval; or (3) congenital long QT syndrome with bradyarrhythmias, or when conventional beta-blocker therapy is unsuccessful. Permanent pacemaker implantation is not necessarily an effective prophylactic measure against sudden death in patients following their operation who are receiving drug therapy for atrial tachyarrhythmias, and so is not absolutely indicated. New developments in lead technology have made transvenous lead systems more feasible for pediatric use. Because epicardial leads are required for small infants and for cosmetic reasons in some older children, design improvements are needed to enhance epicardial lead performance. Rate-responsive pacing is an acceptable alternative to dual-chamber pacing for augmenting exercise tolerance, and for children with sinus node dysfunction it is the preferred pacing mode. Pacemakers with automatic antitachycardia capabilities and with noninvasive electrophysiology features are valuable in children with atrial tachyarrhythmias. New data suggest that chronic atrial pacing also may be effective in controlling atrial tachyarrhythmias. New developments in pacemaker systems for the young parallel those for the older population, but differences between adult and pediatric patients demand ongoing increased participation by pediatric cardiologists.

Permanent cardiac pacing in infants and children

This clinical review details our 15 year experience with permanent cardiac pacemakers in 81 infants and children. Pacing was found inappropriate in one infant. The other 80 patients were paced because of congenital heart block [24], post-operative block [50], or sick sinus syndrome [6]. Maintenance of long-term pacing requires all too frequent re-operation for battery depletion [37%], lead related problems [32%] or wound dehiscence [31%]. Problems related to pacemaker size and the presence of a high myocardial threshold are particularly important in the pediatric patient. In spite of these problems, children requiring cardiac pacemakers can be extremely well, their prognosis depending almost entirely on the presence of underlying heart disease.

Cardiac pacing in children and adolescents

Nineteen patients aged 1 month to 18 years underwent implantation of a cardiac pacemaker and were followed up for up to 9 years (average duration of pacing 54 months). Complete heart block was present in 16 patients and sinus nodal dysfunction in 3. Heart block was presumably of congenital orgin in eight, secendary to cardiac surgery in seven and subsequent to cardiac catheterization in one. Sinus nodal dysfunction was of presumed congenital origin in one and occurred after cardiac surgery in two. Pacing was required because of syncopal attacks in eight patients, three of whom had congestive heart failure or low cardiac output on physiologic studies. It was required in four because of congestive heart failure, in two because of low cardiac output (one with a wide QRS complex), and in five for postoperative rhythm control. With return of sinus rhythm after 2 and 3 months, respectively, pacing was discontinued in two patients. One child was partially corrected disease died within 3 months, one died of wound breakdown and sepsis after 10 months of pacing and one died suddenly 4 years after implantation. All others have returned to normal activity; only one requires cardiac medication. The degree of emotional stability has been striking. Asynchronous and atrial synchronous pacing are of equal therapeutic value. The very small radiofrequency implanted receiver has been useful in younger children. The major problems have been caused by the large size and short longevity of the generators and the child's growth stressing the lead system. Transvenously implanted pacemakers have presented no greater management problems than those placed during thoracotomy.

Permanent cardiac pacemakers in children: technical considerations

Placement of permanent cardiac pacemakers in children presents technical problems that are not encountered in the adult. Problems unique to pacemaker implantation in children are related to the patient's size, the relative bulkiness of pulse generators, the lack of subcutaneous tissue, and the child's growth and long life expectancy. Based on our experience with implantation of 27 permanent cardiac pacemakers in 13 children, we have found that the use of small pulse generators, placement of epicardial leads, insertion of properitoneal pulse generators, and use of recharabeable pacemakers are satisfactory methods in children.

Permanent pacemaker implantation in infants, children, and adolescents. Long-term follow-up

Twenty-four patients in the pediatric age range who underwent implantation of a cardiac pacemaker for treatment of complete atrioventricular (A-V) block were followed for an average of five years (range 1-12 years). The etiology of the A-V block was surgical in 13 cases, congenital in nine, and acquired in two. Twenty patients had symptoms of cerebrovascular insufficiency and four had congestive heart failure. To date, 18 of the 24 patients studied are alive and well. Death occurred in six patients, five of whom had complex congenital heart defects, and one of whom had Refsum's disease. Death probably was caused by complete heart block despite pacemaker treatment in four patients, and congestive heart failure in two. In 18 of the 24 children with disabling complete A-V block, pacemaker therapy provided relief of symptoms and prolonged life.

Long-term follow-up of two infants with an implanted cardiac pacemaker

The clinical course of two patients with congenital heart block who had pacemaker implantation at age 7 and 8 months, respectively, is reviewed. One patient at age 10 years has had nine pulse generators inserted; the other has had six implantations, the most recent a lithium iodine pacemaker, during 8 1/2 years of observation. Both patients have shown normal physical development and emotional maturation despite multiple hospitalizations and pacemaker replacements, thus demonstrating that electrical pacing, initiated in infancy, can be maintained through childhood without adverse effects.

Direct cardiac shunt for hydrocephalus of infancy and childhood. Technical note

The authors describe a technique for direct cardiac shunting in which an adult-size ventriculoatrial catheter is coiled in an intrathoracic Silastic pouch and implanted in infants with hydrocephalus. In three patients so treated, serial chest films have shown progressive uncoiling of the catheter over a follow-up interval of 6 to 14 months.