上室頻拍の機序

The Mechanism of Supraventricular Tachyeardia

　発作性・持続性上室頻拍（PAT）の発生機序として，従来より，心房ないしは房室接合部よりおこる異所性自動性によるものと^1〜4），心房・洞房・房室結節をふくむreentryによるものと^5〜15）が考えられている。最近，われわれはPATを有する4症例について，His東電位の記録，右心房刺激などを行ない，発生機序についての検討を行なったので報告する。

The mechanism for paroxysmal or Pevsistent supraventricular (PAT) was studied in 4 patients with previous history of PAT but without WPW syndrome. The His bundle electrogram was recor-ded 1) during sinus rhythm, 2) during episode of PAT, 3) at the onset of PAT and 4) during atrial pacing. The changes in AH interval indu-ced by atrial pacing were also studied in 5 control subjects.

The PAT was found to be initiated in the two different ways. One was characterized by the induction of PAT preceded by a premature atrial contraction (PAC) with prolonged AH interval.