The 12-lead surface electrocardiogram (ECG) and intracardiac electrograms were simultaneously recorded on an optical disk (EP Med Systems, Inc., NJ, USA). For mapping, an 8-French ablation catheter with a 4 mm tip was positioned close to the RB, or close to the left bundle branch (LB) by a retrograde approach via the aortic valve if necessary. Three to four multipolar catheters were introduced through percutaneous femoral vein punctures under fluoroscopic guidance and positioned at the high right atrium (HRA), His bundle region (HBE), right ventricular apex (RVA), right ventricular outflow tract (RVO), and right bundle branch (RB). We retrospectively explored the clinical and electrophysiological characteristics of those BBR-VT patients including the presence of any underlying heart disease, clinical symptoms, and the ECGs at baseline and during induced BBR-VT.Īfter written informed consent was obtained from each patient, an EPS was performed under sedation with an intravenous infusion of fentanyl and midazolam in one patient and propofol in the others. Eight of 252 patients (3.1%) had inducible BBR-VT. Methodsįrom January 1991 to May 2008, we performed VT ablations in 252 patients in our institution. Therefore, we reviewed the characteristics of BBR-VT in order to find the reason for the higher inducibility of an RBBB type BBR-VT in our institution. 1–3, 5 In our institution, however, our experience has suggested that BBR-VT with a right bundle branch block (RBBB) configuration is inducible as often as that with an LBBB pattern during the electrophysiological study (EPS). In past reports, BBR-VT with a left bundle branch block (LBBB) morphology was reported to be predominantly induced by programmed ventricular stimulation (PVS) and presented as a sustained VT. 1–3 The underlying heart disease associated with BBR-VT includes idiopathic cardiomyopathy, 2, 4, 5 old myocardial infarction, 1, 2, 4, 5 valvular disease, 2, 5–7 myotonic dystrophy, 8 and isolated conduction disturbances of the His-Purkinje system (HPS). BBR-VT accounts for 6–8% of all inducible sustained VTs. Bundle branch reentrant ventricular tachycardia, Right bundle branch block configuration, Atrial pacing, Isoproterenol, Programmed ventricular stimulation Introductionīundle branch reentrant ventricular tachycardia (BBR-VT) is a macroreentrant tachycardia which utilizes the bundle branches as essential components of the reentrant circuit.
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