The effects of exercise training on arterial baroreflex sensitivity in neurally mediated syncope patients.

AIMS The clinical effects of different modalities of treatment for neurally mediated syncope have been studied for years; however, their influences on its pathophysiological mechanisms still have not been determined. This research aimed to observe the effects of physical training, tilt training, and pharmacological therapy on the arterial baroreflex sensitivity and muscle sympathetic nerve activity in neurally mediated syncope patients. METHODS AND RESULTS Seventy patients with recurrent neurally mediated syncope were included in this study. Patients were divided into the following four groups, depending on the treatment proposed: (i) physical training, (ii) tilt training, (iii) pharmacological therapy, and (iv) control group. All patients underwent an autonomic evaluation with microneurography, when the vagal and sympathetic arterial baroreflex gain were tested, using graded infusions of phenylephrine or sodium nitroprusside, before and 4 months after the interventions. The vagal and sympathetic arterial baroreflex gain significantly increased after a 4-month protocol of physical training. Tilt training, pharmacological therapy, and the control group had no significant change in the arterial baroreceptor responses. CONCLUSION Physical training improves arterial baroreflex sensitivity in neurally mediated syncope patients and could be applied as a non-pharmacological therapeutic alternative for these patients.

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