Heart Rate Variability Analysis: A Useful Tool to Assess Poststroke Cardiac Dysautonomia.

BACKGROUND

Neurogenic heart syndrome represents a phenomenon often encountered in clinical practice after ischemic stroke. Further poststroke cardiovascular complications are possibly related to cardiac autonomic dysregulation. Multiple Trigonometric Regressive Spectral (MTRS) analysis of the heart rate variability (HRV) allows a precise evaluation of cardiovascular modulation under different conditions.

OBJECTIVES

This research aims to evaluate the impact of the middle cerebral artery (MCA) ischemic stroke on cardiac autonomic function, using the MTRS analysis of HRV, during sympathetic and parasympathetic activation tests.

METHODS

The authors analyzed HRV parameters in 20 patients who had a right and 20 who had a left MCA ischemic stroke, under rest condition and during autonomic activation tests (deep breathing and standing tests). Data were compared with 20 age-matched and sex-matched healthy controls.

RESULTS

Patients who had a right MCA ischemic stroke presented a decreased vagal modulation of the heart rate compared with healthy controls and patients who had a left MCA ischemic stroke, in resting state and during autonomic activation tests. Decreased root mean square of the successive differences, pNN50, high frequency, and high-frequency normalized units values (P<0.05) and increased low frequency/high frequency ratio (P<0.05) in resting state and during autonomic activation tests in patients who had a right MCA stroke indicate a sympathetic predominance in the control of the heart rate. The parasympathetic activation test did not change the sympathovagal balance in this group of patients.

CONCLUSIONS

The autonomic nervous system represents an attractive target for the therapeutic approach. As MCA ischemic stroke, especially in the right hemisphere, seems to cause significant long-lasting autonomic dysregulation, implementing early pharmacological or nonpharmacological intervention for autonomic restoration may improve the outcome of patients who had an ischemic stroke.