Abstract WP377: Heart Rate Variability Biofeedback Improves Cardiac Autonomic Function in Patients With Acute Ischaemic Stroke: A Randomized Controlled Study

Introduction: In patients with acute ischaemic stroke (AIS) dysregulation of cardiac function with decreased heart rate variability (HRV) due to impaired integrity of the autonomic nervous system is a frequent complication which is associated with increased mortality and worsening of clinical outcome. HRV biofeedback has previously been suggested to improve cardiac autonomic function by increasing parasympathetic tone. Hypothesis: We hypothesized that HRV biofeedback can be used to complement stroke unit care and alleviate autonomic cardiac dysfunction following AIS. Methods: We randomly allocated patients with AIS to either receive 9 sessions of HRV (n=24) or sham (n=24) biofeedback in addition to standard stroke unit care. These patients underwent detailed assessment of autonomic cardiac function including analysis of HRV via standard deviation of NN intervals (SDNN) and spectral analysis. Furthermore, we assessed vasomotor and sudomotor autonomic function, severity of autonomic symptoms and neurological and functional outcomes. Results: We included 48 patients (19 females, ages 65±14 years, baseline NIHSS 2.2 ± 2.2, mean ± standard deviation). Patients who had undergone HRV biofeedback displayed improved cardiac function compared to baseline (SDNN 72.6 ± 52.4 ms vs. 45.5 ± 34.7 ms, p<0.01) which was not seen in those who received sham biofeedback (p=ns). Similar changes were seen on spectral analysis measures of parasympathetic function (p<0.01). Improvement of autonomic cardiac function following HRV biofeedback was paralleled by decreased severity of autonomic symptoms (p<0.05). Contrasting our observation of an increase in predominantly parasympathetic parameters such as CVNN, sympathetic measures of sudomotor and vasomotor function remained unchanged in both groups (p=ns). Neurological and functional outcomes were unchanged immediately post intervention, however 3-month follow up is yet to be completed. Discussion: HRV biofeedback can modulate autonomic cardiac function post AIS to increase HRV and alleviate autonomic symptoms which might be beneficial in facilitating recovery from functional impairment. This seems to be mediated by a predominantly parasympathetic mechanism of action.