Rapid recovery of post-stroke cardiac autonomic dysfunction - causes to be considered.

Abstract

Acute stroke frequently causes cardiovascular-autonomic dysfunction (CAD). Studies of CAD-recovery are inconclusive while post-stroke arrhythmias may wane within 72 hours. We evaluated whether post-stroke CAD recovers within 72 hours upon stroke-onset in association with neurological improvement or increased use of cardiovascular medication. In 50 ischemic-stroke patients (68±13 years) who - prior to hospital-admission - had no known diseases nor took medication affecting autonomic modulation, we assessed NIHSS-scores, RR-intervals (RRI), systolic, diastolic blood-pressures (BP), respiration-rate, parameters reflecting total autonomic modulation [RRI-standard-deviation, 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 (assessment-1) and 72 hours after stroke-onset (assessment-2) and compared data to those of 31 healthy-controls (64±10 years). We correlated delta-NIHSS-values (assessment-1 - assessment-2) with delta-values of autonomic parameters (Spearman-Rank-correlation tests; significance: P<0.05). At assessment-1, patients were not yet on vasoactive medication and had higher systolic blood pressure, respiration-rate, heart rate, i.e. lower RRIs, but lower RRI-Standard-Deviation, RRI-coefficient-of-variance, RRI-low-frequency-powers, RRI-high-frequency-powers, RRI-total-powers, RMSSDs, and baroreflex-sensitivity. At assessment-2, patients were on antihypertensives, had higher RRI-Standard-Deviation, RRI-coefficient-of-variance, RRI-low-frequency-powers, RRI-high-frequency-powers, RRI-total-powers, RMSSDs, and baroreflex-sensitivity but lower systolic blood pressure and NIHSS-values than at assessment-1; values no longer differed between patients and controls except for lower RRIs and higher respiration-rate in patients. Delta-NIHSS-scores correlated inversely with delta-values of RRI-Standard-Deviation, RRI-coefficient-of-variance, RMSSDs, RRI-low-frequency-powers, RRI-high-frequency-powers, RRI-total-powers, and baroreflex-sensitivity. In our patients, CAD-recovery was almost complete within 72 hours after stroke-onset and correlated with neurological improvement. Most likely, early initiation of cardiovascular medication and probably attenuating stress supported rapid CAD-recovery.