Effects of Heart Rate Variability Biofeedback in Patients With Acute Ischemic Stroke

Background: Ischaemic stroke is among the most common causes for severe disability and death in the industrialized world with steadily increasing prevalence due to the demographic change. Thus more than 795,000 people yearly have a stroke in the United States of America, of which circa 610,000 people have new strokes or a stroke for the first time in their life (Benjamin, et al. 2017). Symptoms of ischaemic stroke patients include dysregulation of the autonomic nervous system such as cardiac and vascular autonomic dysfunction, which correlate with increased mortality and poor functional outcome. This study aims to assess the effects of heart rate variability biofeedback (HRV-Biofeedback) in patients with acute ischaemic stroke. Furthermore, the investigators aim to examine the impact of the intervention on cardiac autonomic function and further autonomic parameters such as sudomotor (sympathetic perspiratory gland function) and vasomotor function (sympathetic arterial function). Methods/design: An explorative prospective study is undertaken in 48 patients with acute ischaemic stroke who undergo either 9 x 10-minutes lasting biofeedback sessions over a period of 3 days, or sham-biofeedback (control-group) also over a period of 3 days under randomized controlled conditions. The HRV-biofeedback technique is based on the recording and visualization of heart rate variability, which is visible in real-time for the patient on a computer screen. In the training sessions, the patient is instructed to breath in a predefined frequency, which has been shown to yield optimal neurologic-cardiac regulation (respiratory sinus arrhythmia) with high heart rate variability. Sham-biofeedback takes place under identical testing and environmental conditions with subjects looking at a computer screen but not having heart rate variability recorded and visualized. Moreover, the patients do not follow any breathing instructions, which could possibly have any influence on the heart rate variability. The sham intervention is applied to rule out any placebo effect. Before the first and after the last biofeedback-session, measurements of heart rate variability and polygraphical recordings of further autonomic functions (sudomotor function and vasomotor function) are undertaken. Severity of the autonomic functions is captured by a specific survey (Survey of Autonomic Symptoms). The modified Rankin Scale is used to assess functional outcome after acute ischaemic stroke at baseline, with the conclusion of the biofeedback-sessions, and in the context of a telephone-interview after a period of 3 months. Furthermore, severity of common stroke related symptoms is recorded at baseline and after the last training session using the National Institutes of Health Stroke Scale. All assessments as well as all biofeedback training sessions take place at the Stroke Unit of the Department of Neurology, University Hospital Carl Gustave Carus Dresden, Germany.