心筋部分血流予備量比（FFRmyo）測定時のパパベリンの冠動脈内注入にて心室細動を来した1例

A Case with Ventricular Fibrillation after Intracoronary Papaverine Injection for the Measurement of Myocardial Fractional Flow Reserve (FFRmyo)

要旨　心筋部分血流予備量比（FFR_myo）測定時の塩酸パパベリン投与後に心室細動を来した1例を経験した．患者は慢性腎不全で維持透析中の67歳女性で労作時胸痛を主訴に入院．冠動脈造影にて左前下行枝seg.7に75％，回旋枝seg.13に90％，seg.15に75％の有意狭窄を認め，seg.7に対するPTCA適応決定のためFFR_myoを測定した．検査時の心拍数は毎分46で，パパベリン投与26秒後に多形性心室頻拍から心室細動を来しDC 300 Jによる除細動にて洞調律に回復した．FFR_myoは0.75以上でseg.7に対してはPTCAは施行せずseg.13とseg.15にMulti-Linkステントを留置した．本例では検査時に徐脈を認め，パパベリンによる再分極の不均一性の増強が心室細動の原因となった可能性がある．本例のように女性で，検査前に徐脈を認める症例ではパパベリンの冠動脈内注入には注意を要する．

　A 67-year old woman was admitted to our hospital because of effort angina. She underwent coronary arteriography, which revealed severe narrowing in the left circumflex artery and intermediate stenosis in the left anterior descending (LAD) artery. When FFR_myo across LAD lesion was recorded, 14mg of papaverine was injected into the left coronary artery. Baseline ECG showed sinus bradycardia (heart rate 46/min), and the QT interval significantly increased after the papaverine injection. The multiple premature ventricular complexes developed and turned out torsade de pointer that degenerated into ventricular fibrillation. Cardioversion was performed and sinus rhythm was regained. The value of FFR_myo of LAD lesion was higher than 0.75, so percutaneus coronary intervention was not performed. The mechanism of papaverine-induced arrhythmias is still uncertain. One possibility is that papaverine prolongs myocardial repolarization and aggravates the dispersion of ventricular repolarization.