Orthotopic heart transplantation hemodynamics: Does atrial preservation improve cardiac output after transplantation?

Background: We have described an alternative technique for orthotopic heart transplantation (bicaval Wythenshawe technique) which maintains the right and left atrial anatomy and contractility. Methods: Fifty patients were randomized into two groups: group A (n = 25) who had orthotopic heart transplantation using the bicaval Wythenshawe technique and group B (n = 25) who had conventional (Lower and Shumway) technique of orthotopic heart transplantation. We compared the cardiac output (measured by thermodilution technique) with atrial activation (AAI pacing) to cardiac output without atrial activity (VVI pacing) in both groups to identify any beneficial hemodynamic effects. All patients were studied the first and second weeks after transplantation. The inaccuracies of comparing cardiac output measurements caused by different loading conditions, inotropic state, and systemic vascular resistance were eliminated by using the patient as his or her own control. Results: The difference between the measured cardiac output with atrial pacing and ventricular pacing was 1.42 ± 0.44 L/min in group A in comparison with 0.32 ± 0.4 L/min in group B (p = 0.001 Wilcoxon signed rank). The percentage of atrial contribution to the cardiac output in group A was 30% ± 12% (standard deviation), 95% confidence interval in comparison with 7% ± 9%, 95% confidence interval in group B. The mean stroke volume in group A was higher in sinus rhythm (65 ± 19.2 ml) and atrial pacing (62 ± 17.7 ml) compared with ventricular pacing (49.17 ± 16.43 ml) p = 0.001. In group B no statistical difference was found between stroke volume measured with atrial (47.71 ± 6.23 ml) or ventricular pacing (46.9 ± 6.35 ml). Conclusions: We conclude that the bicaval technique of orthotopic heart transplantation preserve the atrial kick and its contribution to cardiac output early after transplantation.