Double Product and Autonomic Function as Predictors of Quality of Life in Heart Transplant Recipients: A Cross-Sectional Study

Introduction: Heart rate control by the autonomic nervous system (ANS) is impaired in heart transplant (HT) recipients, leading to increased resting heart rate, metabolic demand, and fatigue, which can impair their quality of life (QoL). In this study, we hypothesized the association of hemodynamics and autonomic function as predictors of QoL in HT recipients. Methods: This is a cross-sectional study conducted with HT recipients aged >= 18 years at ambulatorial accompaniment. Blood pressure was used for hemodynamics assessment, and heart rate variability (HRV) was used for ANS assessment. QoL was assessed by the 36-item Short Form Health Survey. The significance level was set as P=0.05. Results: Twenty-two volunteers were included in the study. Systolic blood pressure (SBP) and double product (DP) were significantly negatively associated with the physical functioning domain of QoL. DP, the number of consecutive normal RR interval differences > 50 ms (NN50), and the percentage of normal RR intervals that differed by > 50 ms from the adjacent interval (PNN50) exhibited negative association with the physical role domain. NN50 and PNN50 were significantly associated with bodily pain, social functioning, and emotional role domains. SBP was negatively associated with the vitality domain. Considering general and mental health domains, no variable demonstrated significant association. DP, NN50, and PNN50 were negatively associated with the total score of QoL. Conclusion: This study demonstrated DP and HRV as predictors of QoL in HT recipients. These innovative results can become a relevant therapeutic target for improving QoL in HT recipients prior to its deterioration.