Determinants of peak VO(2) in heart transplant recipients

OBJECTIVE: To establish the determinants of the peak VO(2) in heart transplant recipients. METHODS: Patient's assessment was performed in two consecutive days. In the first day, patients performed the heart rate variability assessment followed by a cardiopulmonary exercise test. In the second day, patients performed a resting echocardiography. Heart transplant recipients were eligible if they were in a stable condition and without any evidence of tissue rejection diagnosed by endomyocardial biopsy. Patients with pacemaker, noncardiovascular functional limitations such as osteoarthritis and chronic obstructive pulmonary disease were excluded from this study. RESULTS: Sixty patients (68% male, 48 years and 64 months following heart transplantation) were assessed. Multivariate analysis selected the following variables: receptor's gender (P =0.001), receptor age (P =0.049), receptor Body Mass Index (P =0.005), heart rate reserve (P <0.0001), left atrium diameter (P =0.016). Multivariate analysis showed r=0.77 and r2=0.6 with P <0.001. Equation: peakVO(2) =32.851 - 3.708 (receptor gender) - 0.067 (receptor age) - 0.318 (receptor BMI) + 0.145 (heart rate reserve) - 0.111 (left atrium diameter). CONCLUSION: The determinants of the peak VO(2) in heart transplant recipients were: receptor sex, age, Body Mass Index, heart rate reserve and left atrium diameter. Heart rate reserve was the unique variable positively associated with peak VO(2) . This data suggest the importance of the sympathetic reinnervation in peak VO(2) in heart transplant recipients.