Koji Azegami

Transient Complete Atrioventricular Block Provoked by Ventricular Pacing in a Patient With Nonsustained Ventricular Tachycardia

Abstract A 75-year-old woman with complete left bundle branch block underwent electrophysiological study (EPS) to assess the conduction in the His-Purkinje conduction system and to further investigate the electrical instability in the ventricle, which was suggestive by the findings of nonsustained ventricular tachycardia in ambulatory monitoring. Transient complete atrioventricular (AV) block was provoked by ventricular pacing, and the intracardiac recordings proved that the site of AV block was distal to the His bundle. This phenomenon was not related to the rate or the duration of the ventricular pacing. The transient impairment of the conduction appeared to be due to the fatigue phenomenon in the His-Purkinje system.

Aborted Sudden Cardiac Death Associated with Short QT Syndrome

A 43‐year‐old male was transferred to our institute. His heart rhythm on admission was ventricular fibrillation (VF) which was successfully defibrillated with a direct current shock (DC). A diagnosis of short QT syndrome (SQTS) was made on the basis of an abnormally short QT interval of 280 ms during the sinus rhythm. During treatment for mild total hypothermia, VF recurred repeatedly necessitating DCs. Nifekalant at a dose of 0.3 mg/kg was intravenously administered, the QT interval was prolonged from 280 to 370 ms and VF no longer recurred. Subsequently the patient underwent implantation of an implantable cardioverter defibrillator.

Serious ventricular tachyarrhythmias in cases with apical hypertrophic cardiomyopathy

心尖部肥大型心筋症 (AHCM) は通常予後良好とされているが, 当施設で最近10年間に経験したAHCM31例中2例に重症心室性不整脈が合併し“aborted sudden death”をきたした例や失神例が見られ, 植え込み型除細動器およびアミオダロン治療を必要とした.重症心室性不整脈合併例と非合併例にて, 加算平均心電図検査, 運動負荷検査, ホルター心電図検査, 123-I-MIBG心筋シンチグラムを施行した結果, 合併例においてMIBG心筋シンチグラム検査で左室広範囲に有意なtraoer uptakeの低下が見られたが, それ以外の検査では両者間に有意な相違点は見られなかった.また, 他の2例において頻脈性心房細動による重症心不全をきたしたため長期入院加療を要した.AHCM例は概ね予後良好であるが, まれに予後不良例もみられるため, 通常の肥大型心筋症と同様の注意深い対応が必要であると考えられる.