Lesion configuration effect on stroke-related cardiac autonomic dysfunction.

BACKGROUND: Autonomic nervous system (ANS) malfunction is a common sequel of stroke. The impact of lesion configuration on the expression of stroke-related ANS malfunction is largely unknown. OBJECTIVE: To examine the relationship between stroke location and ANS malfunction, as reflected in cardiac rhythm control. METHODS: 25 patients in the subacute phase post first-ever ischemic stroke were recruited for the study. Heart rate monitor (RS800CX) was used to record RR intervals analyzed as heart rate variability (HRV) parameters. Lesion data derived from follow-up CT scans of the brain was used for voxel-based lesion symptom mapping (VLSM) analysis (MEDx software, Medical Numerics) to identify voxels of the normalized brain where damage exerts a significant impact on the HRV scores. RESULTS AND CONCLUSION: ANS control of the cardiac rhythm, as expressed in the HRV, was affected by damage to a large array of cortical and subcortical structures in the right hemisphere. In the left hemisphere only damage confined to a small set of subcortical structures was shown to exert a significant impact on the recorded HRV measures. In addition, VLSM analysis disclosed a different pattern of cerebral control over two widely used standard time-dependent measures of the HRV - SDNN and RMSSD, with the former being sensitive to damage in a much larger array of structures in both hemispheres.

The cardiac autonomic nervous system response to different daily demands among patients at the sub-acute phase post ischemic stroke and healthy controls.

BACKGROUND: Autonomic disturbances are a common phenomenon in patients' post-stroke, characterized by hypo function of the para-sympathetic and/or overactive sympathetic system. The impact of autonomic disturbances on physical therapy tasks during the rehabilitation period has not yet been assessed. OBJECTIVE: To describe the response of the cardiac autonomic nervous system during different tasks, among patients and age-matched healthy controls. METHODS: Nineteen patients in the subacute phase post first-ever ischemic stroke, and 16 controls. The Polar advanced heart rate monitor (RS800CX) was used to record RR intervals at rest, during paced breathing exercise, while performing different types of muscle contractions, and during single and dual task conditions. RESULTS: RR intervals and heart-rate variability (HRV) parameters were significantly lower among patients post stroke, both at rest and during most of the activities tested. Among the control group a significant autonomic adaptation was seen in the form of reduced RR intervals and HRV during muscle contraction and a significant increase in these parameters during slow breathing, no significant changes were observed among patients post stroke. CONCLUSION: Patients post-stroke experience hyper sympathetic function at rest and less adaptive cardiac autonomic control during different activities, which all may have an impact on rehabilitation outcomes.

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. 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.

Heart rate autonomic regulation system at rest and during paced breathing among patients with CRPS as compared to age-matched healthy controls.

OBJECTIVE: The objective of this study is to assess the autonomic nerve heart rate regulation system at rest and its immediate response to paced breathing among patients with complex regional pain syndrome (CRPS) as compared with age-matched healthy controls. DESIGN: Quasiexperimental. SETTING: Outpatient clinic. SUBJECTS: Ten patients with CRPS and 10 age- and sex-matched controls. METHODS: Participants underwent Holter ECG (NorthEast Monitoring, Inc., Maynard, MA, USA) recording during rest and biofeedback-paced breathing session. Heart rate variability (HRV), time, and frequency measures were assessed. RESULTS: HRV and time domain values were significantly lower at rest among patients with CRPS as compared with controls. A significant association was noted between pain rank and HRV frequency measures at rest and during paced breathing; although both groups reduced breathing rate significantly during paced breathing, HRV time domain parameters increased only among the control group. CONCLUSIONS: The increased heart rate and decreased HRV at rest in patients with CRPS suggest a general autonomic imbalance. The inability of the patients to increase HRV time domain values during paced breathing may suggest that these patients have sustained stress response with minimal changeability in response to slow-paced breathing stimuli.