潜在性WPW症候群による房室回帰性頻拍によって失神発作を繰り返した閉塞性肥大型心筋症の1例

A Case of Syncope-associated Atrioventricular Reentrant Tachycardia with Hypertrophic Obstructive Cardiomyopathy

　症例は54歳，女性．46歳頃，動悸に引き続く失神発作を経験．54歳時にも動悸発作から失神を生じ，近医に緊急搬送．収縮期血圧40mmHgと著明な血圧低下と心拍数200／分の上室性頻拍を認めた．ATPによって頻拍は停止し，血圧，意識レベルとも改善した．精査加療目的にて当科紹介された．入院後精査にて閉塞性肥大型心筋症と診断された．電気生理学的検査では，心房期外刺激により頻拍の誘発が可能であり，頻拍中，収縮期血圧は40〜60mmHg台と低下し，失神の前駆症状を伴った．この頻拍は，右側後壁の副伝導路を介する順行性房室回帰性頻拍と考えられた．同副伝導路に対し高周波カテーテルアブレーションを施行し伝導途絶に成功した．頻拍発作中，著明な血圧低下による失神発作を繰り返した肥大型閉塞性心筋症患者に対し，高周波カテーテルアブレーションに成功した1例を経験したので報告する．

A 54-year-old female had experienced recurrent epi- sodes of palpitation and syncope since the age of 46. At the age of 54, she experienced syncope following palpita-tion and was admitted to a nearly hospital. Her systolic blood pressure was 40 mmHg and electrocardiogram revealed supraventricular tachycardia (200/min). Intra-venous administration of adenosine triphosphate ter-minated this tachycardia and blood pressure and con-sciousness were recovered. She was admitted to our hospital for the evaluation of syncope and su-praventricular tachycardia. By noninvasive and inva-sive tests, she was diagnosed as having hypertrophic obstructive cardiomyopathy. During electrophysiologic study, supraventricular tachycardia was induced by the application of a single extra stimulus to the high right atrium and was associated with hypotension (40~60 mmHg) and near syncope. This tachycardia wasdiagnosed as orthodromic atrioventricular reentrant tachycardia using a right posterior concealed accessory pathway. We performed radiofrequency catheter abla-tion for the right posterior accessory pathway, resulting in the complete elimination of atrioventricular reentrant tachycardia. Hence, we reported a case of a patient with hypertrophic obstructive cardiomyopathy who had atrioventricular reentrant tachycardia associated with hypotension and syncope. Complete elimination of this tachycardia was accomplished by radiofrequency cath-eter ablation.