Comparison of combined substrate-based mapping techniques to identify critical sites for ventricular tachycardia ablation.

BACKGROUND: Established electroanatomic mapping techniques for substrate mapping for ventricular tachycardia (VT) ablation includes voltage mapping, isochronal late activation mapping (ILAM), and fractionation mapping. Omnipolar mapping (Abbott Medical, Inc.) is a novel optimized bipolar electrogram creation technique with integrated local conduction velocity annotation. The relative utilities of these mapping techniques are unknown. OBJECTIVE: The purpose of this study was to evaluate the relative utility of various substrate mapping techniques for the identification of critical sites for VT ablation. METHODS: Electroanatomic substrate maps were created and retrospectively analyzed in 27 patients in whom 33 VT critical sites were identified. RESULTS: Both abnormal bipolar voltage and omnipolar voltage encompassed all critical sites and were observed over a median of 66 cm2 (interquartile range [IQR] 41.3-86 cm2) and 52 cm2 (IQR 37.7-65.5 cm2), respectively. ILAM deceleration zones were observed over a median of 9 cm2 (IQR 5.0-11.1 cm2) and encompassed 22 critical sites (67%), while abnormal omnipolar conduction velocity (CV <1 mm/ms) was observed over 10 cm2 (IQR 5.3-16.6 cm2) and identified 22 critical sites (67%), and fractionation mapping was observed over a median of 4 cm2 (IQR 1.5-7.6 cm2) and encompassed 20 critical sites (61%). The mapping yield was the highest for fractionation + CV (2.1 critical sites/cm2) and least for bipolar voltage mapping (0.5 critical sites/cm2). CV identified 100% of critical sites in areas with a local point density of >50 points/cm2. CONCLUSION: ILAM, fractionation, and CV mapping each identified distinct critical sites and provided a smaller area of interest than did voltage mapping alone. The sensitivity of novel mapping modalities improved with greater local point density.

Atrial fibrillation ablation: reaching the mainstream.

INTRODUCTION AND AIMS: Ablation of atrial fibrillation (AF) has evolved rapidly in the decade since its inception. We aimed to review the results of this evolution as reflected in the published literature. METHODS: Publications through 2005 were reviewed, and data included if there was information on the technique used, and follow-up of at least 6 months. RESULTS: More than 23,000 patients met criteria for inclusion. There has been a steady improvement in reported outcomes (P<0.001). Variations on radiofrequency catheter ablation for pulmonary vein isolation result in apparent elimination ("cure") or improvement of AF in 75%, and surgical techniques are even better. CONCLUSIONS: Catheter ablation of AF is now a mainstream procedure. Continuing technical advances are needed to achieve better results with more uniformity and reduced procedure times.