Twave alternansを認めた先天性QT延長症候群の1例

A Case of Congenital Long QT Syndrome Associated with T Wave Alternans

　71歳，女性．30歳頃より緊張時等に年2,3回の失神発作を認め，平成2年精査入院．聴力正常，理学的所見異常なし．心電図上QTcは0.68秒と延長し，トレッドミル運動負荷試験では負荷直後にTwave alternans,2分30秒後に心室頻拍を認めた．緊張にて失神発作が誘発され，血清K,Mgの補正によりQTcは0.70秒から0.58秒とやや短縮し，β遮断剤の投与により以後失神発作は誘発されなくなった．トレッドミル運動負荷試験にて各薬剤の効果を検討したところ，β遮断剤が最も有効であった．

A case was presented in which a rare T wave alter-nans occurred in association with congenital long QT syndrome. A 71-year-old woman, who had experienced several syncopal attacks per year for the previous forty years, was admitted for further evaluation of the syncope. She had a family history of sudden death (sister) and QT prolongation (son). Electrocardiogram showed a corrected QT interval of 0.68 seconds. Tread-mill exercise-tolerance test revealed both T wave alter-nans immediately after exercise and torsades de pointes 150 seconds after exercise. The syncope was induced by the mental excitation.