日本新生児成育医学会雑誌　第29巻　第1号　47～51頁（2017年）

日本新生児成育医学会雑誌　29(1)：47-51；2017　

受付日：平成27．09．17

受理日：平成28．05．09

上室性頻拍の発作予防にフレカイニドとプロプラノロールの併用が有効であった早産児

Combination of Flecainide and Propranolol Prophylaxis for Supraventricular Tachycardia in a Preterm Infant

岩手医科大学　医学部　小児科学講座

Department of Pediatrics, School of Medicine, Iwate Medical University

外舘玄一朗・松本　敦・小西　雄・白澤聡子・鳥谷由貴子・葛西健郎・高橋　信・千田勝一

Genichiro SOTODATE，Atsushi MATSUMOTO，Yu KONISHI，Satoko SHIRASAWA，Yukiko TOYA，Takeo KASAI，Shin TAKAHASHI，Shoichi CHIDA

Key Words：preterm infant，supraventricular tachycardia，flecainide，propranolol

　早産児は正期産児よりも上室性頻拍（supraventricular tachycardia，以下SVT）の発生率は高いが，反復は少ないとされている。SVTを反復する早産児で抗不整脈薬2剤の併用がSVT の消失に有効であったので報告する。症例は在胎30週，1,254gで出生した男児。生後5日から発作性頻拍が出現し，生後37日から回数が増加した。心電図検査では非発作時にデルタ波はなく，発作時にはQRS幅が狭く，RR間隔が一定で，RP間隔がPR間隔よりも長かった。アデノシン三リン酸で発作が停止したため，永続性接合部回帰頻拍か稀有型房室結節リエントリー頻拍が考えられた。生後42日からフレカイニドの内服を開始したが頻拍は減少せず，生後69日にプロプラノロールを追加した後に頻拍は減少し，生後105日には消失した。この間，心不全の徴候や薬剤の副作用を認めなかった。フレカイニドにプロプラノロールを併用するとSVT の予防効果が強まるとされており，この2剤の併用はSVTを反復する早産児でも有効と考えられた。

　The incidence of supraventricular tachycardia（ SVT） is higher in preterm infants than in term infants, but recurrence is infrequent. We present the case of a preterm infant with recurring SVT for which the combination of two types of antiarrhythmic agents proved effective in eliminating SVT. The patient was a male infant born at a gestational age of 30 weeks and weighing 1,245g. SVT was observed from the age of 5 days, and the number of incidents increased when the patient reached the age of 37 days. Electrocardiography showed no delta waves at times when there were no paroxysms. During paroxysms, the QRS width was narrow, RR interval was constant, and RP interval was longer than the PR interval. Since paroxysms stopped with the administration of adenosine triphosphate, the differential diagnoses included permanent form of junctional reciprocating tachycardia and atypical atrioventricular nodal reentrant tachycardia. Oral flecainide was started when the patient was 42 days old, but the SVT did not improve. With the addition of propranolol from when the patient reached the age of 69 days, SVT decreased and subsequently disappeared when the patient was 105 days old. Neither signs of heart failure nor adverse effects from pharmacotherapy were observed during this time. The combination of propranolol with flecainide was thought to have strengthened the effect of preventing SVT, and the combination of these two drugs proved beneficial even in a preterm infant with recurrent SVT.