Patient Demographics and Implant Indication

• Age at initial implant

  
  The age at initial pacemaker has varied little since 1983. The average age remains near 7 years. This average age reflects the need of children with congenital heart block for pacemakers in their late teenage and early adult years and for the increasing incidence of sinus node disease many years following surgery. Brackets represent 1 standard error about the mean.

• Indication for initial implant
  • Surgically induced heart block

    
    Surgical heart block remains the most common reason for pacemaker implantation. Again the percentage of initial implants due to surgical heart block has not varied significantly since 1983-1984. There was a slight decrease in 1989-1990 but the incidence has now increased back to approximately 40% of all initial implants. Yet the cardiac surgical procedures resulting in heart block are more complex and procedures once associated with the occurrence of heart block such as isolated ventricular septal defect closure are now rarely associated with heart block.

    
    The age at initial implant of children with surgical heart block is dependent upon the age at which surgery is felt advisable. While the age at which cardiac surgery is performed in general has decreased, the greater complexity of procedures now performed in older children has caused the average initial implant age to remain unchanged at approximately 4 years. The brackets represent 1 standard error about the mean.

  • Surgically induced sick sinus syndrome (sinus node disease)

    The percentage of initial implants due to surgically induced sinus node disease or sick sinus syndrome has remained constant since 1983 accounting for 15% to 20% of initial implants. Thus, nearly 60% of all initial implants in children are a consequence of cardiac surgical procedures.

  • Congenital heart block

    The majority of the remaining 40% of initial implants are a consequence of congenital heart block. The age at which a pacemaker is needed is variable from 1 day to young adulthood. The presence of structural cardiac disease often necessitates earlier pacemaker implantation, but in each child the need for a pacemaker must be based on the presence of symptoms.

  • Non-surgically induced sick sinus syndrome

    Non-surgically induced sinus node disease does occur but is uncommon. This indication accounts for less than 5% of initial implants.

  • Control of tachyarrhythmias by either pacing devices or severe bradycardias induced by arrhythmic drugs

    Implantation of pacemakers for termination of tachycardias has been limited with only a few per year reported to the Registry. Somewhat more common is the need for pacemaker placement due to bradycardias induced by antiarrhythmic drug therapy. Yet this accounts for only a few new implants each year.

• Accompanying structural cardiac disease

  

Structural lesions most commonly associated with surgical heart block are depicted above. These tend to be the more complex lesions to repair particularly atrioventricular septal defects (AVSD). The majority of aortic valve replacements developing heart block have been complex repairs with annular enlargement (Konno procedure). Many of the children with a single ventricle have had L-transposition of the great arteries which may well have resulted in heart block unrelated to the surgical procedure. Double outlet right ventrcular repairs often require a complex intraventricular patch placement resulting in heart block. Finally isolated ventricular septal defect closure (VSD) now is less commonly associated with heart block. The majority of children requiring pacemakers following ventricular septal defect closure have had unusual locations of their defect or have had multiple defects. Heart block is more common when such defects are located in the inlet portion of the ventricular septum.

Return to Main page