Diagnostic value of Q waves outside standard precordial lead points in left anterior myocardial infarction undetectable by standard 12-lead electrocardiogram.
Body surface potential maps were recorded for 52 patients with solitary anterior myocardial infarction and 57 normal subjects. All patients had pure anterior wall asynergy on a left ventriculogram but no diagnostic Q wave on the standard 12-lead electrocardiogram. Q wave (greater than 30 msec) distributions on the body surface of the patients and normals were compared. The frequency of Q waves in the area above V1-V2 and in the right middle chest was significantly higher in patients than in normals. The sensitivity of Q waves for asynergy in leads from both these areas was 19-60%. The positive predictive value was 67-94%. The frequency of Q waves was significantly higher in severe asynergy than in mild asynergy. A combination of two selected unipolar leads from these areas yielded a sensitivity and specificity of 33% and 95%, respectively. With a combination of three leads, these values were 42% and 93% and with four leads 48% and 88%, respectively. The results indicate that several unipolar leads from the area above V1-V2 and from the right middle chest in addition to the standard 12-lead electrocardiogram may improve the electrocardiographic diagnostic accuracy of myocardial infarction.
Yabe
S
S
First Department of Internal Medicine, School of Medicine, Nagoya University, Japan.
Hayashi
H
H
Ishikawa
T
T
Watabe
S
S
Miyachi
K
K
Yokota
M
M
Sotobata
I
I
D004562:Electrocardiography / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D011237:Predictive Value of Tests