Catheter ablation (CA) targeting premature ventricular contraction (PVC) from Purkinje fibers can be an effective therapy for refractory ventricular fibrillation (VF) after myocardial infarction (MI). We experienced two cases in which catheter ablation targeting PVC initiating VF after percutaneous coronary intervention (PCI) in post-MI patients was effective despite transient early recurrences of VF. The first patient (a 68-year-old woman with MI) developed drug-refractory VF 3 days after PCI to the left anterior descending artery (LAD) and left circumflex artery. CA targeting Purkinje potential preceding PVC at the infarcted area eliminated both the PVCs and VF. Three days after the procedure, the VF attacks relapsed by a different type of PVC. However, the VF responded to conventional treatments and disappeared thereafter. In the second patient (an 83-year-old woman with old MI), refractory VF attacks occurred after PCI to the LAD. CA targeting Purkinje potential preceding two distinct types of PVC successfully suppressed the VF. Although the VF relapsed 2 days after CA, it was suppressed by conventional treatment and disappeared the next day. .

症例は71歳男性. 拡張型心筋症 (DCM) に対する除細動器付き両心室ペースメーカ (CRT-D) 植込み後も心不全を契機とした心室頻拍 (VT) を繰り返し認めていた (持続性心房細動[AF]で心房リードは留置されず). 7年前に2種類のVTに対しカテーテルアブレーション (RFCA) を施行したが1種類は残存, アミオダロンを中心とした薬物療法を継続していた. 今回VT stormで再入院, RFCA施行. Substrate mappingで心外膜側は低電位領域を認めず, 心内膜側の基部側壁および中隔に限局した低電位領域を認め, 同部位への通電で以後VTの頻度は減少した. 術中両室pacing後に同じ連結期を有する心室期外収縮 (PVC) を契機とした非持続性心室頻拍 (NSVT) を認めた. 術後は洞調律を維持していたため心房pacingが可能となり, AAIにて自己QRSを温存した結果, 心不全が改善しVTの再発なく心不全管理が良好となった. 結語 : RFCAおよび心房リード追加が本例のVT storm抑制に有効だった.