Online ISSN: 2187-2988 Print ISSN: 0911-1794
特定非営利活動法人日本小児循環器学会 Japanese Society of Pediatric Cardiology and Cardiac Surgery
Pediatric Cardiology and Cardiac Surgery 35(3): 188-194 (2019)

症例報告Case Report

室房伝導を伴う胎児期心室頻拍症から生後高度房室ブロックとなった1例Advanced Atrioventricular Block after Postnatal Cardioversion for Fetal Ventricular Tachycardia: A Case Report

1独立行政法人地域医療機能推進機構九州病院小児科Department of Cardiology, Japan Community Healthcare Organization Kyushu Hospital ◇ Fukuoka, Japan

2独立行政法人地域医療機能推進機構九州病院産婦人科Department of Gynecology and Obstetrics, Japan Community Healthcare Organization Kyushu Hospital ◇ Fukuoka, Japan

受付日:2018年9月21日Received: September 21, 2018
受理日:2019年4月3日Accepted: April 3, 2019
発行日:2019年9月1日Published: September 1, 2019

胎児期発症心室頻拍の新生児例において,生後,電気的除細動による心室頻拍停止後に一過性高度房室ブロックとなった1例を経験したので報告する.在胎39週3日の胎児心エコー図検査で心拍数180回/分の房室解離のない胎児頻拍症を指摘され当院産科へ紹介となり,そのまま娩出となった.出生体重は3,130 gであった.12誘導心電図では左軸偏位・幅広いQRS波を伴うshort RP′頻拍であり,アデノシン三リン酸急速静注により房室解離が見られたので心室頻拍症と診断した.電気的除細動により心室頻拍は停止したが,脚枝ブロックを伴う高度房室ブロック(P波138回/分,QRS波75回/分)となった.血圧32/15 mmHgであったがドパミン投与により血圧は回復した.心エコー図検査では左室拡張末期径16.8 mm,左室駆出率30%であった.生後15時間後より2度房室ブロックを経て,生後2日には正常洞調律へ復し,生後48日に退院した.経過中および退院後のホルター心電図検査でも心室頻拍・房室ブロックの再発は認めなかった.胎児期には心室頻拍による逆行性室房伝導を認めていたにもかかわらず,心室頻拍停止後にHis–Purkinje伝導系の高頻度駆動抑制(overdrive suppression)現象のため高度房室ブロックとなった希な経過であった.

We present a neonatal girl who developed complete atrioventricular block after postnatal cardioversion for fetal ventricular tachyarrhythmia. A pregnant women was referred at 39 gestational weeks due to fetal tachyarrhythmia of 180 bpm and without atrioventricular (AV) dissociation. Subsequently, a baby girl was delivered weighing 3,130 g. Electrocardiography revealed wide QRS tachycardia with left axis deviation, and the esophageal leads revealed a short RP′ duration without AV dissociation. However, AV dissociation was overt after injecting adenosine triphosphate, which suggested ventricular tachycardia. Cardioversion stopped the ventricular tachycardia but led to atrioventricular block with fascicular block (P rate 138 bpm, QRS rate 75 bpm), and the resulting hypotension (32/15 mmHg) was improved by dopamine administration. Echocardiography revealed a left ventricular end-diastolic diameter of 16.8 mm and an ejection fraction of 30%. Serial electrocardiography revealed a second-degree atrioventricular block at 15 hours after birth that reverted to sinus rhythm at day 2 after birth. She was discharged on day 48 after birth. Holter electrocardiographic monitoring did not shown recurrence of either the ventricular tachycardia or the atrioventricular block. The present case was unique because advanced atrioventricular block due to overdrive suppression in the His–Purkinje conduction system followed ventricular tachycardia with ventriculoarterial conduction.

Key words: fetal arrhythmia; ventricular tachycardia; atrioventricular block; ventriculatrial conduction

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