Corrected QT dispersion improves diagnostic performance of exercise testing in diagnosing coronary artery disease.

To determine the best combination of parameters that would improve the diagnostic performance of exercise testing, coronary angiography plus exercise testing were done on 112 patients with angina pectoris and normal electrocardiogram. The univariate predictors of coronary artery disease included: age > or = 40 years, male sex, hypertension, smoking, development of exertional chest pain, decrease in systolic blood pressure (BP) > or = 10 mmHg or systolic BP 3 min post-exercise > 90% of peak, heart rate drop < 12 beats/min 1 min postexercise, exercise-induced ST-segment depression > or = 1 mm. Multivariate logistic regression analysis showed that using either ST depression > or = 1 mm or peak exercise QTDc > 70 ms significantly improved sensitivity and negative predictive value of the test without a significant decrease in specificity.