冠動脈造影中の心電図変化—とくに胸部誘導の変化について

Electrocardiographic changes during selective coronary angiography with refercnce to changes in V1-6

　冠動脈造影時には，造影剤が有するchemical effectsにより，心収縮力の低下ならびに心電図変化が，一過性に生ずることが知られている^1〜3）。

　心電図の変化については，右冠動脈造影時には右軸偏位，左冠動脈造影時には左軸偏位が認められ，それぞれ左脚後枝ブロック，左脚前枝ブロックによっておこると考えられている^4,5）。しかしながらこれらの報告^4,5）は，すべて四肢誘導心電図についてのものであり，冠動脈造影にともなう胸部誘導心電図の変化は知られていない。

Twelve-leads electrocardiograms were obtained during coronary angiography in 73 cases. In cases with normal coronary artery, right coronary artery injections of the contrast medium induced appear-ance of late "r" or increment of R wave amplitude in lead V₁in one-third of the cases, and increment of S in lead V_5,6 in three-forth of the cases. Left coronary injections induced increment of R in lead V_5,6 in all of the cases with normal coronary artery and normal anteroapical wall motion.

Left ventricular dimensions were also obtained echocardiographically under the fixed heart rate. Left coronary injections resulted in the increase of the end-systolic dimension (p<.005), but not the end-diastolic dimension (p>.05).

These electrocardiographic and echocardiograp-hic changes during coronary angiography were as-sumed to be due to the direct effects of contrast medium on the perfused myocardium, and also the increase of R wave amplitude in lead V_5,6 during left coronary injection was presumed not to be due to the "Brody effect".