Ergonovine誘発狭心症におけるベクトル心電図QRS波高およびQRS環変化の検討

Changes of QRS amplitudes and QRS loops of Vectorcardiogram during coronary artery spasm provoked by ergonovine maleate

　貫壁性心筋梗塞症における心電図QRS波変化の診断的価値は確立されている。虚血性心疾患患者の運動負荷による一過性のQRS波の変化は，近年多くの報告があるが，その診断的有用性については議論が多い。一方，冠攣縮による自発狭心症の全経過のベクトル心電図QRSの変化を記録し検討した報告は少ない。今回，著者らはErgonovine maleateを負荷し，冠攣縮を誘発させ，急性虚血時のベクトル心電図QRS波高およびQRS環の変化を検討した。それにより，かかる変化の診断的有用性および病態を明らかにしようとした。

We discussed the relationship between coronary artery spasm provoked by ergonovine maleate and the changes of the QRS amplitudes and the QRS loops of vectorcardiogram (VCG) with Frank's leads.

Nineteen patients with vasospastic stenosis of coronary artery 90% or more were studied. 8 patients with left coronary artery spasm (L-group), 7 patients with left and right coronary arteries spasm and 4 patients with right coronary artery spasm. VCG were recorded on magnetic tape during ergonovine provocative test and transcribed after. Result as follows.

The mean amplitudes of RY, RZ and ΣYR (RX-RY+RZ) in all patients and L-group decreased significantly during anginal attack. The mean am-plitude of SZ in L-group decreased during anginal attack. However there were no significant changes of maximum spatial magnitude vectors. The maxi-mum vectors in the horizontal plane shifted to anterior and the initial 20 msec vectors in the horizontal plane shifted posterior in 5 patients with total occlusion of left anterior descending artery due to spasm. An infarcted pattern was observed in these 2 patients.

These results suggested that the localized changes of myocardial conduction time in transient ischemia could produce the specific changes of the QRS wave.