The prognostic value of QT dispersion in patients presenting with acute neurological events

QT dispersion (QTD) reflects heterogeneity of myocardial repolarization, which is modulated by the central nervous system. Previous studies have shown increased QTD to be a predictor of adverse outcomes in various cardiac states. The objective of this study was to determine the significance of QTD in patients hospitalized with cerebrovascular accidents (CVA) and transient ischemic accidents (TIA). We studied 140 consecutive patients (72 years old, 48% male) admitted to our institution with neurologic events from January 1998 to April 1998. QTD was calculated from admission electrocardiogram as the difference between maximum and minimum QT intervals in at least 11 of 12 leads. Three separate instruments (NIH Stroke Scale, Barthel Index and Modified Rankin Scale) were used to assess functional status on discharge. QTD was higher in patients with intercerebral hemorrhage as compared to CVA and TIA (70 15 msec versus 53 27 msec versus 48 31 msec, respectively; p = 0.03). Increasing QTD was associated with lower functional outcomes on all 3 scales (all p < 0.05) and with higher mortality (p = 0.02). QTD was higher in patients with congestive heart failure (80 43 msec versus 47 24 msec; p = 0.006) and with carotid disease (59 32 msec versus 46 27 msec; p = 0.045) as compared to those without. On multivariate analysis, other independent predictors of worse outcome were QTD (odds ratio, 1.35; 95% confidence interval, 1.08 1.68) and a trend toward age (odds ratio, 1.07; 95% confidence interval, 0.99 1.16). On age-adjusted logistic regression, mortality increased by odds ratio of 1.28 and 95% confidence interval of 1.02 1.61 for every 10 msec increase in QTD. QTD is an independent predictor of functional outcome and mortality following acute neurological events. In this setting, QTD reflects neurological injury as well as underlying heart disease.