BUNDLE BRANCH REENTRY VENTRICULAR TACHYCARDIA: PREVALENCE AND OUTCOME
S. Khatri, S. Nicholls*, J. Leitch.
Department of Cardiovascular Medicine, John Hunter Hospital, Newcastle, New South Wales.
Introduction: Bundle branch reentry ventricular tachycardia (VT) is an uncommon but treatable form of VT. The aim of this study was to establish the prevalence and outcome of bundle branch reentry VT.
Method: 101 patients were identified over a 7 year period to have inducible VT in structurally abnormal hearts at electrophysiology study (EPS). Of these, 8 had a form of VT consistent with bundle branch reentry. The records of these patients were reviewed.
Results: Median age was 62 years (17-78). Seven were male. Three had co-existent coronary artery disease. Six presented with syncope and 2 with palpitations. Echocardiography revealed dilated cardiomyopathy in 7 and hypertrophic cardiomyopathy in 1. Resting electrocardiography revealed 5 to be in sinus rhythm and 3 in atrial fibrillation. All had evidence of conduction delay (4 left bundle branch block, 3 partial left bundle branch block and 1 right bundle branch block). At time of study 12 forms of VT were induced (10 bundle branch reentry and 2 myocardial VT). The bundle branch reentry VT had median cycle length 275 msec (230-420). Median baseline HV interval was 72.5 msec (70-100). VT was induced by ventricular extrastimuli in 5 cases, ventricular pacing 4 and atrial pacing 2. Isoprenaline was required in addition in 2 cases. Morphology of the VT was left bundle branch block in 9 and right bundle branch block in 1.
Outcome: Seven proceeded to ablation of the right bundle. The 2 patients with myocardial VT received implantable defibrillators, one following ablation. Two patients continued amiodarone (1 for atrial fibrillation and 1 for myocardial VT) and 1 sotalol for atrial fibrillation. Of those that proceeded to ablation, 1 had recurrent VT treated by the implantable defibrillator, 1 had primary ventricular fibrillation which was managed medically and 4 had no recurrent arrhythmia. Two died due to progressive cardiac failure.
Conclusion: Bundle branch reentry VT is an uncommon but treatable form of ventricular tachycardia. The present of severe heart disease and other forms of VT in these patients can lead to considerable morbidity and mortality.
