Transient QRS axis shift to the right during right coronary artery and/or left circumflex artery spasms.
The QRS axis was measured in 24 patients during ergonovine malate provocation test (EM test). Of 12 patients with significant spasm of the right coronary artery (RCA) and/or left circumflex artery (LCX), the QRS axis shifted to the right in 7 patients after the EM test (mean 8.2 degrees), and the axis shifted back to the left in 9 patients after nitroglycerin administration (mean -9.1 degrees). The sensitivity of right axis shift for RCA and LCX spasm was 58% and the specificity was 80%. Thus, right axis shift seems to be associated with myocardial ischemia due to RCA and LCX spasm and to be useful for the detection of RCA and/or LCX spasms.
First Department of Internal Medicine, Tottori University School of Medicine, Japan.
T
T
Matsumoto
K
K
Ogino
T
T
Kinugawa
A
A
Hoshio
H
H
Miyakoda
H
H
Kotake
H
H
Mashiba
S
S
Endo
D003329:Coronary Vasospasm / Q000175:diagnosis* / Q000503:physiopathology; D003331:Coronary Vessels / Q000503:physiopathology; D004562:Electrocardiography; D004874:Ergonovine / Q000031:analogs & derivatives; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged
D004874:Ergonovine