Torsade de Pointes in Advanced Atrioventricular Block: A Cause of Syncope

Cha, Kwang Soo; Park, Tae Ho; Lee, Cheol Jong; Jeong, Chi Young; Lee, Sung Won; Moon, Chang Hoon; Kim, Jin Ho; Lee, Gyum Cheol; Kim, Hyeong Kweon; Kim, Moo Hyun; Kim, Young Dae; Kim, Jong Seong

Abstract

Advanced or complete atrioventricular (AV) block is frequently regarded as a cause of informed syncopal attacks even though escape rhythm is maintained. Torsades de pointes (TdP) may be a significant complication of AV block associated with QT prolongation. Maintaining ventricular rate over 70 beats/min is known to be important to normalize QT interval and to reduce the possibility of bradycardia-related TdP recurrence after pacemaker implantation. We report one case of syncopal attacks associated with TdP in a 70 year old female patient with advanced AV block and prolonged QT interval. She was referred to evaluate palpitation and syncope. Advanced AV block and QT interval prolongation were seen with electrocardiography, but junctional escape rhythm was maintained. Syncopal attacks occurred during temporary pacemaker insertion. Multiple episodes of nonsustained polymorphic ventricular tachycardia and TdP related to syncopal attacks were demonstrated by 24-hour Holter monitoring. A permanent pacemaker was implanted and ventricular rate was set over 70 beats/min resulting in no recurrence of TdP and syncope.