Diagnostic significance of a small Q wave in precordial leads V(2) or V(3).
BACKGROUND
An abnormal Q wave is usually defined as an initial depression of the QRS complex having a duration of > or =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).


CONCLUSIONS
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.
Katsuno
Tetsuya
T
Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Japan.
Hirao
Kenzo
K
Kimura
Shigeki
S
Komura
Masatoshi
M
Haraguchi
Go
G
Inagaki
Hiroshi
H
Hachiya
Hitoshi
H
Isobe
Mitsuaki
M
D000368:Aged; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000175:diagnosis*; D023921:Coronary Stenosis / Q000175:diagnosis; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D016017:Odds Ratio