부산대학교 도서관

Introduction: Endocarditis of the aortic valve has a propensity to create A-V conduction disturbances in up to 10% of cases. Torsades de pointes (TdP) is polymorphic ventricular tachycardia in the setting of prolonged QT interval and bradycardia that is typically preceded by a short-long-short sequence of ventricular activation. We present a case of infective endocarditis with aortic root abscess leading to acute 2:1 A-V conduction and culminating in TdP.Case Summary: A 30-year-old male with history of IV drug use and bioprosthetic aortic valve repair presented with pleuritic chest pain, nausea and vomiting. He was febrile and tachycardic with a systolic murmur at the right upper sternal border. Initial electrocardiogram showed sinus rhythm with no conduction abnormalities. Transthoracic echocardiography showed a large aortic valve vegetation with an abscess cavity. Blood cultures grew Streptococcus oralis. Two days later, he developed VT/VF arrest requiring external defibrillation. Preceding ECGs and telemetry showed sinus tachycardia with new left bundle branch block and prolonged QTc. This progressed to 2:1 AV block with abrupt transition to relative bradycardia and ventricular ectopy leading to short-long-short ventricular intervals and subsequent TdP. A temporary pacemaker was placed, and he underwent an aortic root reconstruction with valve replacement.Discussion: While both the etiology of TdP and aortic root abscesses leading to conduction system disease are well described, this case exhibits the real time progression of aortic abscess involvement. The patient presented with a normal QRS morphology. During hospitalization, he developed new LBBB, and the appropriate sinus tachycardia then deteriorated into 2:1 AV conduction leading to relative bradycardia. This abrupt transition with QTc prolongation sets up the nidus for ventricular ectopy (due to early after depolarizations) with salvos of short-long-short sequences causing TdP.