実験的右室梗塞における右側胸部誘導ST上昇の意義

Significance of right precordial ST elevation in experimental right ventricular infarction

　最近になって右室梗塞（RVI）は下後壁梗塞の約半数に合併するとされ，治療法の選択という点からもその診断は重要なものとなりつつある。またRVIにおける右側胸部誘導のST上昇は臨床的にRVIの診断として重要であるばかりでなく心電図学的にも興味ある問題を含んでいる。この問題の解明には純右室梗塞におけるECG変化の検討が有用と思われるが，臨床的な純右室梗塞は稀であり，実験的にも純右室梗塞のECG変化を検討した報告は数少ない。そこで我々はagar gelを用いて経カテーテル的に冠動脈閉塞を行い，右冠動脈（RCA），左冠動脈回旋枝（LCX），RCA＋LCXの閉塞を各々作成し，RVIにおける右側胸部誘導ST上昇の意義に関して考察した。

We produced experimental isolated right ventricu-lar infarction (RVI) with closed chest method, and examined ECG changes of right precordial leads and changes of cardiac output (C.O) in 19 dogs. As a result, ECG showed ST depressions in leads, II, III, aVF and V₂~V₆ and ST elevations in aVR lead in all 15 cases of the proximal occlusion of right coronary artery (RCA). In 10 of 15 dogs ST elevations in some right precordial leads occurred, and the sensi-tivity of ST elevation in single right precordial lead was 60% (V₅R), 53% (V₄R) and 47% (V₃R and V₁), respectively for the detection of RVI. When left cir-cumflex artery (LCX) was occluded, ST elevation in V₄R lead after RCA occlusion was blocked. Therefore, it is thought that the sensitivity of ST elevation in right precordial lead may be lower than expectation in identifying RVI. Concerning anterior chest leads, none of 15 dogs with RVI showed ST elevations in leads V₂~V₆ in this study, If ST elevations in right precordial leads did not appear, variation of C.O was small and C.O reduced in proportion to the extension of ST elevations in right precordial leads.