Background: Prolonged corrected QT interval (QTc) holds independent prognostic importance
in predicting mortality in patients with coronary artery disease, diabetes mellitus and
congestive heart failure. However, its association with all cause or cardiac mortality in the
general population remains unclear. We evaluated the relationship between prolonged QTc
and total mortality among patients with syncope.
Methods: This was a retrospective study of 348 patients presenting to the emergency department
with syncope of any etiology over a period of one year. All patients with atrial fibrillation,
left bundle branch block and cardiac devices (pacemaker/defibrillator) were excluded. Prolonged
QTc interval was defined as QTc interval ≥ 440 ms. The primary end point for this
study was total mortality in patients presenting with syncope.
Results: There were 58 (16%) deaths in this population during a mean follow-up of 30 months.
Patients with prolonged QTc interval had significantly higher mortality when compared to
those with normal QTc interval (22% vs 11%; p = 0.004). This significance was not retained
after adjustment for covariates in the Cox regression model, where we found that age ≥ 65 years
(hazard ratio [HR] 7.9; 95% confidence interval [CI] 1.9–32.9; p = 0.004) and QTc interval
≥ 500 ms (HR 3.5; 95% CI 1.56–8.12; p = 0.002) were predictors of increased mortality
among patients with syncope.
Conclusions: In elderly patients presenting to the emergency department with syncope, QTc
interval ≥ 500 ms helps identify patients at higher risk of adverse outcomes. (Cardiol J 2011;
18, 4: 395–400
