The diagnostic value of QRS changes for prediction of coronary artery disease during exercise testing in women: false-positive rates.

Objectives: The false positive rate of electrocardiographic exercise testing (ET) for coronary artery disease (CAD) in women ranges from 38 to 67%, using the ST-T changes (ST-T) criteria. The aim of this study was to compare the diagnostic accuracy of QRS duration change criteria with ST-T change criteria during ET.

Methods: We studied 234 women (mean age 58+/-17 years, range 27-83 years), of whom 160 were pre-menopausal (PrMW; mean age 41+/-9, range 27-56) and 74 were post-menopausal (PoMW; mean age 65+/-7, range 57-83). All participants underwent ET to rule out CAD, followed by thallium stress testing (TL). QRS duration, measured with a computerized optical scanner and ST-T changes at peak ET were compared with TL. An ischemic QRS response was defined as an exercise-induced prolongation of QRS duration >3 ms.

Results: The sensitivities of QRS duration changes for the entire study group, the PrMW group and the PoMW group in comparison with TL, were 93, 88 and 92%, respectively, while the corresponding rates of specificity were 91, 85 and 91%, respectively. The sensitivities of ET ST-T changes for the entire study group, for the PrMW group and for the PoMW group were 48, 46 and 54%, respectively, while the corresponding rates of specificity were 62, 75 and 79%, respectively. The false-positive rate was 20% for ischemic ST-T and 4% for ischemic QRS duration for the entire study population.

Conclusions: Computer-measured QRS duration changes during ET are more sensitive and specific than ST-T changes for the detection of ischemia in women.