Abstract
Background and aims
Ischemic stroke often causes cardiovascular autonomic dysfunction. We previously showed associations between higher National Institutes of Health Stroke Scale scores and more severe cardiovascular autonomic dysfunction. This study evaluated associations between infarct-volume and parameters of cardiac autonomic modulation in patients with acute ischemic stroke in the middle cerebral artery (MCA) territory.
Methods
In 48 patients with acute MCA stroke (68±15 years old, 23 men, 25 women)), we monitored RR intervals (RRI), systolic, diastolic blood pressures (BPsys, BPdia), and respiration (RESP) at rest within 24 hours after stroke-onset. We calculated parameters of total cardiac autonomic modulation (RRI-standard-deviation (RRI-SD), RRI-coefficient-of-variation (RRI-CV), RRI-total-powers), sympathetic (RRI-low-frequency-powers (RRI-LF), normalized (nu) RRI-LF-powers, BPsys-LF-powers) and parasympathetic modulation (root-mean-square-of-successive-RRI-differences (RMSSD), RRI-high-frequency-powers (RRI-HF), RRI-HFnu-powers), sympathetic-parasympathetic balance (RRI-LF/HF-ratios), and baroreflex-sensitivity (BRS). The infarct-volume was calculated using the Ellipsoid model ABC/2 (where A = longest dimension in axis x, B = longest perpendicular dimension to axis x (y), and C = total length in z dimension) from the diffusion-weighted Magnetic Resonance image (DWI) within 24 hours upon stroke-onset or Computed Tomography (CT) taken within 48 hours upon stroke-onset.
Results
Values of infarct-volumes correlated positively with RRI-LF-nu-powers (correlation-coefficient: 0.297, P=0.038) and RRI-LF/HF-ratios (correlation-coefficient: 0.414, P=0.003), negatively with RRI-HFnu-powers (correlation-coefficient: -0.297, P=0.038). Patients with infarct-volumes above 50ml had higher RRI-LF-nu-powers and RRI-LF/HF-ratios but lower RRI-HF-nu-powers than patients with smaller infarct-volumes.
Conclusions
In our patients with acute ischemic MCA-stroke, increased infarct-volume was associated with a shift towards increased sympathetic and reduced parasympathetic cardiac modulation. These changes bear an increased risk of secondary complications.
Conflict of interest
For all authors: Nothing to disclose related to the current study.