Potential Cardiovascular Autonomic Dysfunction in Burn Survivors: A Pilot Study

Burn injury is increasingly recognized as a chronic condition associated with long-term cardiovascular risk; however, few studies have explored underlying mechanisms. This study aimed to evaluate cardiovascular autonomic function in individuals with chronic burn injuries. Ten adults, 3-11 years post burn injury of 10%-70% TBSA (mean: 34% ± 5%) underwent standard autonomic function tests: Valsalva's maneuver, paced breathing, and isometric handgrip. Heart rate and blood pressure responses were compared to either established normative values or to matched controls for each respective test. Burn survivors had significantly lower Valsalva ratios (1.32 ± 0.19) compared to age/sex normative values (1.47 ± 0.07, P < .05) and reduced heart rate variability (root mean square of successive differences, RMSSD) compared to matched controls (31 ± 21 vs 57 ± 19 ms, P < .05), indicating impaired cardiac vagal modulation. Valsalva ratio and RMSSD were related in the burn survivors (r = 0.58, P = .079), and RMSSD but not Valsalva ratio, tended to relate to burn size (r = -0.57, P = .082). No group differences were observed in responses to isometric exercise. Chronic burn injury appears to be associated with diminished cardiac vagal control which may underlie elevated cardiovascular risk observed in this population.