ABSTRACT
The catheter ablation of idiopathic ventricular arrhythmias is accepted as a first-line treatment as it successfully eliminates about 90.0% of such arrhythmias. One of the most challenging ventricular arrhythmias originates from the left ventricular summit (LVS), a triangular epicardial space with the left main bifurcation as its apex. This area accounts for about 14.0% of LV arrhythmias. The complex anatomy of this region, accompanied by proximity to the major epicardial coronary arteries and the presence of a thick fat pad in this region, renders it a challenging area for catheter ablation. This article presents a review of the anatomy of the LVS and relevant regions and discusses novel mapping and ablation techniques for eliminating LVS ventricular arrhythmias. Additionally, we elaborate on the electrocardiographic (ECG) manifestations of arrhythmias from the LVS and their successful ablation via the direct approach and the adjacent structures.
ABSTRACT
BACKGROUND: The finding of bundle branch block (BBB) in patients with syncope suggests that paroxysmal atrioventricular block (AVB) or ventricular tachyarrhythmia (VT) may be the cause of syncope. Guidelines for cardiac pacing and cardiac resynchronization therapy have been recommended to perform electrophysiological study (EPS) for confirming main cause of syncope. Therefore, the aim of our study was to evaluate the role of EPS in patients with syncope and BBB. MATERIALS AND METHODS: We evaluated 133 patients (mean age 63 ± 13.8 years) with past history of syncope and BBB from April 2002 to December 2010 who referred to Arrhythmia clinic in two tertiary care centers. All patients underwent EPS on admission time. The frequency distributions of AVB and VT in patients were determined. RESULTS: Left bundle branch block was diagnosed in 184 (82.1%) patients. 133 of them had preserved left ventricular ejection fraction (LVEF ≥45%) that in 91 (68.4%) of those, EPS finding was normal. In 41 (30.8%) patients AVB was reported. In 2 (1.5%) patients VT and atrioventricular nodal reentrant tachycardia were seen. Coronary artery disease was more common in patients with AVB and abnormal EPS finding (P = 0.02). CONCLUSION: Ventricular tachyarrhythmia was a rare electrophysiological finding in those with syncope, bifascicular block, and preserved LVEF. Considering cost-effect benefit, pacemaker or implantable loop recorder implantation is suggested; however, EPS may not be necessary to perform before permanent pacemaker implantation.
