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

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.