Wataru Shimizu

心室頻拍（VT）を合併する特殊心筋疾患は，催不整脈性右室心筋症（ARVC）や心サルコイドーシスが主である．【方法】VTを合併するARVC 84例，および心サルコイドーシス17例におけるアブレーション成績と長期予後を検討した．【結果】ARVCでは，平均9.2±6.5年の経過観察中に，VTの再発は31例（37％），心不全での入院は18例（21％），心原性死亡は7例（8％），心臓突然死は5例（6％），心不全死は2例（2％）に認めた．アブレーションは48例に施行し，81％でVTの誘発不能となった．経過観察中31％でVTの再発を認めた．心サルコイドーシスに伴うVT 17例に対し，アブレーションを施行したところ，9例（53％）で成功，１例は心外膜アプローチが必要であった．平均49±58ヵ月の経過観察期間中，アブレーション成功例9例中2例（22％）でVTが再発した．【結果】ARVCおよび心サルコイドーシス患者に対するVTアブレーション成績はいまだ不十分であり，今後の成績改善が待たれる．

Since 1995, when a potassium channel gene, hERG (human ether-à-go-go-related gene), now referred to as KCNH2 , encoding the rapid component of cardiac delayed rectifier potassium channels was identified as being responsible for type 2 congenital long-QT syndrome, a number of potassium channel genes have been shown to cause different types of inherited cardiac arrhythmia syndromes. These include congenital long-QT syndrome, short-QT syndrome, Brugada syndrome, early repolarization syndrome, and familial atrial fibrillation. Genotype-phenotype correlations have been investigated in some inherited arrhythmia syndromes, and as a result, gene-specific risk stratification and gene-specific therapy and management have become available, particularly for patients with congenital long-QT syndrome. In this review article, the molecular structure and function of potassium channels, the clinical phenotype due to potassium channel gene mutations, including genotype-phenotype correlations, and the diverse mechanisms underlying the potassium channel gene–related diseases will be discussed.