正常初期QRSベクターについて

The Study on the Normal Inititial QRS Vectors.

1．はしがき

　心室脱分極過程の初期部分の分析が，臨床心電図学に於いて重要な位置を占めることは経験的に古くから注意されていた。殊に心筋梗塞症に於ける異常Q波は，発作後も往々長く残存し，心筋壊死を表現するものとして重要である。

　Grant^1），2）等が標準12誘導心電図を用いて，心電図をベクター的に分析するSpatial Vector Electro—cardiographyを臨床に導入してから，初期0.04秒QRSベクターが心筋梗塞の心電図診断に於いて注目されるに至つた。然し乍ら，単一のベクターをとる際は0.04秒QRSベクターが最も多く初期ベクターを表現するという確証はないし，更に最も基本的な正常初期ベクターの統計的分析については何等の報告をみない。この小文は高年者に於ける正常QRS初期ベクターについて統計的分析を行い，その正常基準を定めるにある。

The Study on the Normal Initial QRS Vectors

Hiroyoshi Mori, M. D.: From the Department of Internal Medicine (2nd Medical Clinic), Tokushima University Medical School

The importance of the initial QRS vector has long been recognized in the clinical electrocardio-graphy. There is, however, no statistical study on the normal standard of the initial QRS vectors. 93 normal men, all in the sixth decade and have been under annual observations these twelve years and did not show any abnormalities, were examined for this purpose. The X, Y, and Z scalar leads of SVEC 111 System were recorded simultaneously with the paper-speed of 10cm/sec. and were analyzed by the vector-analyzer.

All cases were divided by the positions of the mean frontal QRS axis into three groups as vertical position (+60-±180), intermediate position (0-±180), and horizontal position (0-±180). The mean values and the standard deviations of each initial vectors in these three groups are showed in the Table 1. There is no significant difference between horizontal and vertical positions in the azimuth and the magnitude, but there is a significant difference in the elevation.

The ratio of the magnitude between the initial 0.04" QRS and the mean QRS vectors showed values of less than 1±0.091 in three groups. The spatial angles between the initial 0.04" QRS and the mean QRS vectors showed very small angles in three groups. These results indicate the initial instantaneous 0.04" vector has a similarity in its character with the mean QRS vector. So it is hardly considered that the initial instantaneous 0.04" vector represents well the initial QRS vectors.