Right bundle branch block, intermittent ST segment elevation and inducible ventricular tachycardia in an asymptomatic patient: an unusual presentation of the Brugada syndrome?

Abstract

We describe the case of an asymptomatic 54-year-old female who underwent a routine electrocardiogram (ECG) in July 1997, which showed incomplete right bundle branch block and an important ST segment elevation with a coved fashion and the inversion of T waves in leads V1-V2. Her family and personal history was free of any cardiovascular pathology. She previously underwent a routine ECG in 1991 and 1995, showing an incomplete right bundle branch block with a moderate ST segment elevation in leads V1-V2. Exercise test, 24-hour Holter ECG, echocardiogram and QT dispersion analysis were all normal. The heart-rate variability in the frequency domain revealed low vagal tone. The signal-averaged ECG was positive due to the presence of three criteria. The patient underwent an electrophysiologic study. The baseline ECG resembled the ones performed in 1991 and 1995. Sinoatrial node and atrioventricular node were normal. The HV interval resulted of 62 ms. A syncopal polymorphic ventricular tachycardia (cycle length 220 ms) interrupted by electrical defibrillation (200 J) was induced with double extrastimulus during pacing at a cycle length of 600 ms from the apex of the right ventricle. At the end of the study, one minute after a bolus of ajmaline 1 mg/kg, an important ST segment elevation in lead V1 and a left axis deviation appeared. The patient began therapy with sotalol 80 mg t.i.d. and the electrophysiologic study was repeated three days later. A non-sustained polymorphic ventricular tachycardia (cycle length 200 ms) was induced with triple extrastimulus during pacing at a cycle length of 370 ms from the outflow tract of the right ventricle. On the basis of these results and as also suggested by recent reports, we decided to implant an Automatic Implantable Cardioverter Defibrillator.