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Transient QRS axis shift to the right during right coronary artery and/or left circumflex artery spasms
T Matsumoto1, K Ogino, T Kinugawa
1First Department of Internal Medicine, Tottori University School of Medicine, Japan.
Abstract:
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.