Demonstrating time sequence and extent of sustained decrease in native heart ejection fraction after heterotopic transplantation.

Background: In this study we investigate the time sequence and extent of the sustained decrease in native heart ejection fraction (EF) after heterotopic heart transplantation (HHTx) when using gated cardiac blood pool scanning (GCBPS) and transthoracic echocardiography (TTE) One case report of 2 patients used post-operative GCBPS and TTE and found a significant deterioration in native heart EF post-operatively over the course of several years. Comparison with pre-operative measurements using these techniques in a series of patients has not been performed previously.

Methods: Thirteen of 16 HHTx patients with adequate pre- and post-operative GCBPS follow-up were included in this study. All patients also underwent TTE post-operatively and the GCBPS results were correlated with the TTE findings.

Results: GCBPS demonstrated a marked (21.1 +/- 4.7% vs 10.5 +/- 3.7%, p < 0.0001) decrease in native EF post-HHTx. Spontaneous echo contrast in the native left ventricle and/or poor opening of the mitral/aortic valves was noted at Day 1 in 4 of 5 patients who had a TTE at this stage. No further decline was noted between the first and last post-operative GCBPS (10.8 +/- 3% vs 8.6 +/- 2.1%, p = NS).

Conclusions: A dramatic decrease in native heart EF post-HHTx occurs as early as Day 1 post-transplant. Dissociation of ventricular contraction is the most likely cause. Studies have demonstrated that paced linkage (counterpulsation) between the ventricles results in improved hemodynamics. This may have clinical implications as to the timing of ejection of blood from a left ventricular assist device (LVAD) and for providing the best hemodynamics for the ventricle being assisted and for optimizing its chances of long-term recovery.