Qt Interval in Patients with Ischemic Stroke with or Without Cognitive Impairment

Abstract

Introduction Ischemic stroke can lead to heart injury via dysfunction of the autonomic nervous system. QT intervals on electrocardiography (ECG) are susceptible to autonomic influences and their prolongation was associated with increased mortality after stroke. Aims We aimed to study QT intervals in patients with ischemic stroke in chronic phase with and without cognitive impairment. Methods ECGs were recorded in 50 patients with ischemic stroke. QT interval corrected for heart rate (QTc), QT dispersion (QTd), and QT interval variability (QTIV) were measured. The QTVI was calculated as the logarithm of the ratio between the variances of the normalized QT and RR intervals. Using Mini Mental State Examination and Hachinski's ischemic scale we identified vascular dementia (VaD) in 17 patients. Twenty age-matched healthy subjects were examined for comparison. Results We identified QTc, QTd prolongation in patients with ischemic stroke. Comparing patients with ischemic stroke vs. VaD, QTc (412 ±75.2 ms vs 456± 115 ms, p Conclusion Prolongation of QT intervals and increased QTVI occurs frequently after ischemic stroke but most significant changes were found in patients with cognitive impairment. Early detection of cognitive impairment in stroke patients provides better prevention of possible dementia.