カテーテル・アブレーションにより4本の副伝導路を3回の高周波通電で離断したEbstein奇形の1例

A Case of Ebstein's Anomaly with Four Accessory Conduction Pathways Eliminated by Three Radiofrequency Current Deliveries

　Ebstein奇形の副伝導路に対して高周波カテーテル・アブレーションを行い，4本の副伝導路を3回の通電で離断しえた症例を経験した．症例は72歳，女性．心電図にてC型WPW症候群を呈し，心臓カテーテル検査にてEbstein奇形と診断した．臨床的に発作性心房細動とlong RP' tachycardiaを認め，電気生理学的検査にて房室回帰性頻拍（正方向頻拍）が誘発された．long RP' tachycardiaの室房伝導路は減衰伝導を伴う潜在性副伝導路（slow Kent bundle）と考えられた．カテーテル・アブレーションによって三尖弁輪の各々約12mm離れた2本の顕性，1本の潜在性の3本の副伝導路をそれぞれ1回の通電で離断した．アブレーション後，減衰伝導を伴う潜在性副伝導路も消失し，4本の副伝導路が3回の通電で消失したと考えられた．複数副伝導路が多いとされるEbstein奇形においても4本の副伝導路の報告は現在まで1例のみで，稀と考えられたため報告する．

Catheter ablation was performed in a case of a 72-year-old Japanese women with Ebstein's anomaly and WPW syndrome. Four accessory pathways were eliminated with three RF current deliveries. Paroxysmal atrial fibrillation and long RP' tachycardia were clinically documented, along with atrial extra-stimulus induced AV reciprocating tachycardia (orthodromic type). During long RP' tachycardia, a single ventriculanstimulus at the refractory period of His bundle terminated the tachycardia without atrial capture and this retrograde conduction revealed a decremental property. On account of this, this long RP' tachycardia was considered to be a permanent form of junctional reciprocating tachycardia (via the so called slow Kent bundle as the retrograde limb). RE current was delivered at three posteroseptal sites over the tricuspid annulus at a distance of 12 mm respectively and eliminated two manifest accessory pathways and one concealed accessory pathway without decrement property. After these RF deliveries, the slow Kent bundle disappeared. Thus, we considered that three RF current deliveries had eliminated two manifest, one concealed, and one slow Kent bundle.