OBJECTIVE To investigate vagal parasympathetic functions by electromyographic R-R interval variation analyses in heart transplant recipients. METHODS Cross-sectional and longitudinal study. METHODS Department of physical medicine and rehabilitation, university hospital. METHODS Early (n=8; <3 mo) and late (n=17; >1 y) heart transplant recipients and healthy volunteers (n=20) were included. METHODS Not applicable. METHODS The R-R interval variations at rest and in response to deep breathing, Valsalva, and tilt/standup maneuvers were analyzed in all patient and control groups. Further, 8 early heart transplant recipients were followed up at the sixth and twelfth months after transplantation. RESULTS Compared with controls, both early and late transplant recipients had significantly lower R-R interval variation ratios (P<.05). There were no statistically significant differences between the early and late groups (P>.05). R-R interval variation ratios showed no significant changes from baseline (P>.025) in the early heart transplant recipients. CONCLUSIONS The findings of the study suggest that parasympathetic activities are suppressed in the early stage after heart transplantation and do not significantly recover with time. The electromyographic analysis of R-R interval variation is a simple test that may offer an attractive alternative for routine evaluation of autonomic dysfunction in heart transplant recipients.