Heart rate variability - a potential early marker of sub-acute post-stroke infections

Gunther A, Salzmann I, Nowack S, Schwab M, Surber R, Hoyer H, Witte OW, Hoyer D. Heart rate variability a potential early marker of sub-acute post-stroke infections. ?Acta Neurol Scand: 2012: 126: 189-196. (C) 2011 John Wiley & Sons A/S. Objective Infection is the most relevant complication after acute ischemic stroke. Activity of the autonomic nervous system seems to control post-stroke immunodepression. We investigated heart rate variability (HRV) indices that reflect autonomic readjustments as predictors of post-stroke infection. Materials and methods Forty-three patients with acute ischemic stroke were enrolled in a prospective study. The predictability of sub-acute infections (day 4 +/- 1 after admission) was investigated in 34 patients without acute infection by means of HRV indices obtained in the acute period (48 h after admission). Results Sub-acute infection could be predicted in patients without clinical or paraclinical (white blood cell count and C-reactive protein) signs of infection in the acute period at (i) day: increased HFnorm, reduced LFnorm and LF/HF; (ii) night: reduced LF and VLF (P < 0.05). Conclusions HRV indices are candidates for early markers of developing post-stroke infections, preceding routine blood samples. Thus, HRV-based early diagnosis of post-stroke infection should be investigated in more detail as it may have implications as a novel tool for timely and appropriate treatment. A corresponding continuous HRV-based risk assessment using the ECG provided by the routine stroke monitoring system would be possible without any additional burden for patients and staff.