[An experimental study on supraventricular dysrhythmias after intracardiac surgery, with special reference to relationship between injury of the internodal tract and atrial flutter].
Dysrhythmias after atrial reparative surgery for TGA or ASD can be lethal. Experiments were made to analyze their mechanism, and to search preventive methods. 1. Acute effects of atrial incisions were studied by epicardial mapping on the right atriums (RA) subjected to various incisions with or without internodal tract (INT) involvement 101 dogs. Atrial rapid pacing was used to induce sustained AF or af. 2. Chronic effects of atrial incisions were studied on longitudinal incisions with (8 dogs) or without (8 dogs) posterior INT (PINT) involvement. Few months later they were subjected to mapping, inducibility of AF, and histologic study of hearts. 3. Mechanism of induced AF was analyzed using reentrant circuit of AF in the longitudinal PINT incision group. At acute stage, conduction delay specific to each freewall incision was observed. AF or af was induced in 70.0% of the longitudinal incision with PINT involvement, but only in 1 dog without PINT. At chronic stage, AF was induced in 5 dogs (62.5%) which included 4 dogs not showed AF at acute stage. Marked chronic changes were histologically showed in injured atrial portion. Reentrant circuit of AF was demonstrated on RA near tricuspid orfice. The PINT kept intact is important to prevent AF.
Hata
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Second Department of Surgery, Kochi Medical School, Nangoku, Japan.
D000328:Adult; D000818:Animals; D001282:Atrial Flutter / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D006348:Cardiac Surgical Procedures / Q000009:adverse effects* / Q000379:methods; D002648:Child; D004285:Dogs; D004594:Electrophysiology; D005260:Female; D006325:Heart Atria / Q000293:injuries / Q000601:surgery*; D006329:Heart Conduction System / Q000293:injuries* / Q000503:physiopathology; D006801:Humans; D008297:Male