To evaluate whether post-stroke cardiovascular-autonomic dysfunction (CAD) recovers within 72 hours upon stroke-onset in association with improved stroke-severity or increased use of cardiovascular medication.
Acute ischemic stroke frequently causes CAD. Studies of CAD-recovery show inconclusive results while post-stroke arrhythmias may wane within 72 hours. We hypothesize that CAD improves within 72 hours after stroke-onset depending on improved stroke-severity and cardiovascular medication.
In 50 previously unmedicated, ischemic stroke patients (68±13 years; 25 women), we assessed NIHSS-scores, resting electrocardiographic RR-intervals (RRI), systolic, diastolic blood-pressures (BP), respiration-rate (Resp), parameters reflecting total autonomic modulation [RRI-standard-deviation (RRI-SD), RRI-total-powers], sympathetic [RRI-low-frequency-powers, BPsys-low-frequency-powers] and parasympathetic modulation [RMSSD, RRI-high-frequency-powers], and baroreflex-sensitivity within 24 hours, when patients had just been started on cardiovascular medication (assessment-1) and 72 hours after stroke-onset (assessment-2) and compared data to those of 31 age and sex-matched healthy controls (64±10 years; 19 women). We correlated delta-NIHSS-values (assessment-1 – assessment-2) with delta-values of autonomic parameters using Spearman-Rank-correlation tests. Significance was assumed for p<0.05.
Patients were medication-naïve at assessment-1. During assessment-2, 17 patients were on beta-blockers, 28 on angiotensin-converting-enzyme-inhibitors or angiotensin-receptor-blockers, 16 on calcium-channel-antagonists. Compared to controls, patients at assessment-1 had higher BPsys and Resp, but lower RRIs, RRI-SDs, RRI-CVs, RMSSDs, RRI-low-frequency-powers, RRI-high-frequency-powers, RRI-total-powers, and baroreflex-sensitivity. At assessment-2, patients had higher RRI-SDs, RRI-CVs, RMSSDs, RRI-low-frequency-powers, RRI-high-frequency-powers, RRI-total-powers, and baroreflex-sensitivity but lower BPs and NIHSS-values than at assessment-1, and cardiovascular and autonomic parameters no longer differed between patients and controls except for lower RRIs and higher Resp in patients than controls. Delta-NIHSS scores correlated inversely with the delta-values of RRI-SDs, RRI-CVs, RMSSDs, RRI-low-frequency-powers, RRI-high-frequency-powers, RRI-total-powers, and baroreflex-sensitivity.
In our patients, CAD almost completely recovered within 72 hours after stroke-onset and CAD-recovery correlated with neurological improvement. Autonomic recovery was likely promoted by early initiation of cardiovascular medication and possibly also by attenuation of psychological stress occurring with stroke-onset.