POTENTIAL ABLATION OF ACCESSORY ATRIOVENTRICULAR PATHWAYS - INJECTIONOF ALCOHOL INTO THE ATRIOVENTRICULAR GROOVE

Accessory atrioventricular (AV) pathways responsible for the Wolff-Par kinson-White syndrome have been treated successfully by surgical and r adiofrequency catheter ablation techniques. In this study, we explored the feasibility of permanent chemical ablation of accessory pathways by direct injection of 100% ethanol into the canine AV groove. Right c oronary artery blood now and AV compartment pressure were measured in 5 adult mongrel dogs (part I) during injection of saline solution (10 to 15 mL) into the right AV groove. Atrioventricular groove compartmen t pressure increased from 1 +/- 1 to 31 +/- 12 mm Hg (p <0.0001) and r ight coronary artery blood now increased slightly from 117 +/- 17 to 1 38 +/- 44 mL/min (p = not significant). In 8 additional dogs (part II) , 100% ethanol (10 mL) was injected into the left AV groove. After 6 w eeks (n = 6) or 12 weeks (n = 2), histologic examination of the left A V groove demonstrated localized fibrous replacement of injured epicard ial muscle, with only scant inflammatory infiltrate. Mild intimal fibr osis and intimal proliferation were present in the circumflex artery a nd its larger branches, but no significant luminal narrowing was evide nt. Angiograms at 12 weeks (n = 2) demonstrated no significant narrowi ng of the circumflex artery. In summary, injection of 100% ethanol int o the AV groove is capable of locally ablating myocardial tissue, pres umably including conductive tissues, while sparing the coronary arteri es.