Exercise tolerance after beta blockade in recent cardiac transplant recipients

Exercise capacity has been shown to be reduced among cardiac transplant recipients. This observation is directly connected to both the transplanted heart's dependence on circulating catecholamines and the abnormal sympathoadrenal response to exercise in these patients. Taking into account this background, there is reluctance to use beta-blockers after heart transplantation. Nevertheless, this point remains controversial. Our aim was to examine exercise tolerance after an oral dose of atenolol early after cardiac transplantation.

Eighteen nonrejecting, otherwise health, cardiac transplant recipients were included in this study at a mean of 61.9 +/- 25.6 days after surgery; 13 were men. Patients performed controlled exercise to a symptom-limited maximum before and 2 hours after taking an oral dose of atenolol. Heart rate, blood pressure, exercise time, and metabolic equivalent units (METS) were recorded at rest as well as during and after exercise. We compared results depending on taking atenolol.

Resting (101.7 +/- 14.5 vs 84 +/- 12.4 bpm; P = .001) and peak heart rates (128.5 +/- 12.9 vs 100.7 +/- 16 bpm; P = .001) were significantly higher before than after beta blockade. Resting systolic blood pressure was slightly higher before compared with after beta blockade (129.3 +/- 23.6 vs 122.2 +/- 20.3 mm Hg; P = .103). However, there was neither a significant difference in the length of exercise (3.17 +/- 1.96 vs 3.40 +/- 2.48 minutes; P = .918) nor in the estimated oxygen consumption (METS; 5.07 +/- 1.8 vs 5.31 +/- 2.2; P = .229). Furthermore, no patient reported a greater degree of tiredness after beta blockade.

This study showed little adverse effect on exercise tolerance by beta blockade in recently transplanted patients. Atenolol seemed to be safe in this context.