房室接合部刺激

A-V junctional stimulation

　His束刺激はHis束を確認する1つの方法として臨床応用されているが，選択的にHis束のみを刺激する事は必ずしも容易ではない。一口にHis束刺激といっても，刺激される部位は房室接合部領域の種々のソシキであり，体表面心電図のみからでは実際にどの部位が刺激されているのかを的確に推定する事は困難である。今回我我は，犬を用い，刺激条件をかえて直視下に房室接合部領域を刺激した時の被刺激部位について検討した。これに加えて，一部の例ではI度〜III度のHis束内ブロックを作製し，His束遠位部刺激を試みた。

A-V junctional stimulation was made under direct vision by close bipolar electrode in the right heart using canine venous return prepa-ration. Recordings were taken by close bipolar plunge wire electrode inserted into the right atrium, high ventricular septum and free walls of both right and left ventricles simultaneously with surface electrocardiographic leads. In some cases, first to third degree intra-His bundle block was made and distal His bundle stimulation was tried.

Although various portions of AV junctional area were stimulated, high ventricular septum was most frequent, whereas stimulation of the His bundle alone was very few. In selective His bundle pacing, stimulus to R interval was the same as the HR interval in control recording regardless of pacing rate. Therefore, latency does not assume significance in the comparison of these intervals during sinus rhythm and His bundle pacing. Atrial or high ventricular septal potential was not detected in some cases. In-non selective His bundle pacing, high ventricular septal stimulation was most frequent.