Title: Diagnostic Significance of a Small Q Wave in Precordial Leads V2or V3
Abstract: Background: An abnormal Q wave is usually defined as an initial depression of the QRS complex having a duration of ≥40 ms and amplitude exceeding 25% of the following R wave in any contiguous leads on the 12‐lead electrocardiogram (ECG). However, much smaller Q waves are sometimes recorded on the ECG. This study investigated the diagnostic value of the small Q wave recorded in precordial leads V 2 or V 3 on the ECG. Methods: We investigated 807 consecutive patients who underwent coronary angiography. A small Q wave was defined as any negative deflection preceding the R wave in V 2 or V 3 with <40‐ms duration and <0.5‐mV amplitude, with or without a small (<0.1‐mV) slurred, spiky fragmented initial QRS deflection before the Q wave (early fragmentation). ECG and coronary angiographic findings were analyzed. Results: The small Q wave was present in 87 patients. Multiple logistic regression analysis revealed that presence of a small Q wave was a strong independent predictor of any coronary artery stenosis or left anterior descending artery (LAD) stenosis (odds ratio = 2.706, 2.902; P < 0.001, < 0.001, respectively). Conclusion: A small Q wave (<40‐ms duration and <0.5‐mV amplitude) in V 2 or V 3 with or without early fragmentation significantly predicted the presence of CAD and, especially, significant stenosis in the LAD. Ann Noninvasive Electrocardiol 2010;15(2):116–123