Implantation of a permanent pacemaker in a premature infant.

In March 1984 we implanted a permanent, dual-chambered pacemaker in a 2.1-kg premature male infant suffering from congenital atrioventricular block, with an atrial rate of 170 beats per minute, a ventricular rate of 40 beats per minute, and ectopic ventricular escape beats. Through a left anterolateral thoracotomy, we implanted electrodes on the left atrium and left ventricle; through a second incision, in the left flank, we gained access to the retroperitoneal space by finger dissection. The electrodes were then guided through the diaphragmatic sulcus into the retroperitoneal space for attachment to a dual-chambered pacemaker permanently placed in the lumbar region. Our patient was discharged in good condition 23 days after operation and continues, despite some difficulties in establishing optimal pacemaker settings, to enjoy excellent clinical status 55 months after implantation, having moved progressively through pacemaker settings for VVI, DVI, and DDD modes, as his heart has improved. To our knowledge, this is the smallest and first-reported premature infant to be treated successfully for complete heart block with a permanent, physiologic pacemaker. In this surgical procedure, use of epicardial leads decreases the prospect of venous or intracardiac thrombosis; use of long leads situated partly in the chest and partly in the retroperitoneal cavity permits stretching as the child grows; and use of the relatively large peritoneal cavity for placement of the stimulator both protects the unit and permits unimpeded diaphragmatic movement, even in a very small infant. Implantation of this larger, permanent pacemaker, as an alternative to the usual ventricular-demand stimulating electrode, both avoids reoperation and permits flexibility in programming, to meet the changing needs of the growing patient.