Autonomic Cardiac Response to Static and Dynamic Muscle Contractions in Post-Stroke and Healthy Subjects

Abstract

Aim: To describe the response of the cardiac autonomic nervous system to static and dynamic muscle contractions in post ischemic stroke patients 2 and 7 weeks post event, compared with the response of age- and gender-matched healthy controls. Methods: Participants: 12 patients post first stroke at the subacute phase and 12 healthy age-matched controls. Tools: the Polar Advanced Heart Rate Monitor (RS800CX) was used to record inter bit intervals at rest and during grip and cycling. Results: Patients post stroke, both at 2 and 7 weeks post onset time, had higher heart rate and lower heart rate variability (HRV) values at rest compared to controls. A significant reduction in HRV values was noted among healthy controls during static and dynamic muscle contractions compared to baseline. In contrast, stroke patients 2 weeks after onset did not show a cardiac reaction to static contractions. At 7 weeks post onset examination, the stroke patients showed a significant reduction in HRV both during static and dynamic contractions compared to the rest state. Conclusion: Patients post stroke in the subacute phase have alterations in cardiac rhythm regulation both at rest and during muscle effort. The extent of the cardiac autonomic response to muscle contraction is associated with contraction type and time post event. Simple measurement of HRV in different conditions enables monitoring of recovery of autonomic nervous system cardiac control.

Effects of rehabilitation programs on heart rate variability after stroke: a systematic review

“…In this study, patients did not show a normal increase in sympathetic activity in response to the test conditions, mainly due to a hypersympathetic state at rest. During the subacute phase, according to this study and other studies 25,26 , there is apparently a significant physiological change in the ability of the autonomic nervous system to respond adequately to the demands imposed by rehabilitation practices, so only large demands yield expected sympathetic responses 27 . The results indicate a need for rehabilitation focused on improving autonomic cardiac control.…”

“…Despite this result, a significant improvement was found in the functional parameters of post-stroke individuals, such as climbing stairs, and physical training allowed patients to significantly increase their workload. As described by other authors, autonomic impairment after stroke leads to low aerobic capacity 27 . Thus, the importance of early mobilization, rehabilitation, and physical-functional training in post-stroke patients is reiterated.…”