TY - JOUR TI - QRS prolongation on the signal-averaged electrocardiogram versus ST-segment changes on the 12-lead electrocardiogram: Which is the most sensitive electrocardiographic marker of myocardial ischemia? AU - Michaelides, AP AU - Dilaveris, PE AU - Psomadaki, ZD AU - Richter, DJ and AU - Andrikopoulos, GK AU - Pitsilides, N AU - Dounis, V AU - Stefanadis, C and AU - Toutouzas, PK JO - Clinical Cardiology PY - 1999 VL - 22 TODO - 6 SP - 403-408 PB - CLINICAL CARDIOLOGY PUBL CO SN - 0160-9289, 1932-8738 TODO - 10.1002/clc.4960220607 TODO - QRS prolongation; ST-segment changes; myocardial ischemia; coronary artery disease TODO - Background ST-segment changes and QRS prolongation are electrocardiographic (ECG) markers of myocardial ischemia. Hypothesis: This study was undertaken to investigate the appearance of QRS duration changes with or without concomitant ST-segment changes during a typical anginal episode. Methods: For this purpose, 126 patients underwent 12-lead surface ECG and signal-averaged electrocardiogram (SAECG) during typical anginal pain as well as at the time the patient was asymptomatic. In both periods, QRS duration and ST-segment changes were evaluated. All patients underwent cardiac catheterization. Results: Of the 126 patients, 108 (86%) had coronary artery disease (CAD), whereas the remaining 18 (14%) patients had normal coronary arteriograms. During typical anginal pain, 75 of the 108 (70%) patients with CAD and 2 of the 18 (11%) patients with normal coronary arteriograms developed QRS prolongation, whereas 60 of the 108 (56%) patients with CAD and 2 of the 18 (11%) patients with normal coronary vessels developed ST-segment changes. Thus, the sensitivities of QRS prolongation measured by SAECG and of ST-segment changes on the surface ECG for the detection of myocardial ischemia were found to be 70 and 56%, respectively, (p < 0.01), whereas the specificities were both found to be 89% (p = NS). Conclusions: During typical anginal pain, QRS prolongation on the SAECG is more sensitive than are ST-segment changes on the ECG for the detection of myocardial ischemia. ER -