POSTOPERATIVE HEMODYNAMIC IMPROVEMENT WITH PACED LINKAGE OF THE DONOR AND RECIPIENT HEARTS FOLLOWING HETEROTOPIC CARDIAC TRANSPLANTATION

It has been shown that following heterotopic heart transplantation the recipient left ventricle ejects more effectively when it contracts out of phase with the donor left ventricle. However, this is rarely the situation, as the two hearts beat independently of one another and the denervated donor heart tends to beat faster than the recipient. In this study the hemodynamic effects of connecting the two hearts by an external temporary dual-chamber pacemaker were evaluated. The donor right ventricle was sensed and the recipient right atrium paced after a timed delay. The delay was adjusted so that recipient systole coincided with donor diastole. Eleven patients were studied in the first postoperative day. Pacing resulted in an improvement in cardiac output from 5.0 to 5.6 l/min (p = 0.003) and a reduction in pulmonary capillary wedge pressure from 16 to 12 mmHg (p = 0.0035). This was associated with a 35% reduction in inotrope requirements. It is concluded that sequential pacing of the two hearts is a useful adjunct to inotropic support in the postoperative period.