Clinical predictors of arrhythmia recurrences following pulmonary vein antrum isolation for atrial fibrillation: predicting arrhythmia recurrence post-PVAI.

INTRODUCTION: Pulmonary vein antrum isolation (PVAI) is an accepted treatment for atrial fibrillation (AF) refractory to medical therapy. The purpose of this study was to identify the patient, procedural, and follow-up factors associated with arrhythmia recurrences following PVAI. METHODS AND RESULTS: Clinical data were prospectively collected on all 385 consecutive patients who had 530 PVAI (age 58 ± 11 years, 63% paroxysmal AF-PAF, follow-up 2.8 ± 1.2 years) between February 2004 and March 2009. ECGs were recorded at each follow-up visit with Holter monitoring 1, 3, 6, and 12 months following PVAI and every 6 months thereafter. Recurrences < 3 months post-PVAI were defined as early, 3 months-1 year post-PVAI as late, and > 1 year post-PVAI as very late. Relationship between predictor variables and outcomes was modeled using Cox proportional hazards analysis. Late recurrences occurred in 42% with a lower rate among PAF versus non-PAF patients (39% vs 56%, P = 0.001). Of the 256 patients with ≥ 1-year follow-up, 121 (47%) had no arrhythmia off antiarrhythmic drugs (AADs) 1 year post-PVAI; 36 (30%) of these had a very late recurrence. In multivariate analysis, non-PAF, hypertension, and prior AAD failure predicted recurrence. When entered into the model, early recurrences remained the only predictor of late recurrences. CONCLUSION: Patients with non-PAF, hypertension, and prior failure of multiple AAD were more likely to experience arrhythmia recurrence post-PVAI. Early recurrences were the strongest predictor of late recurrences. Late and very late recurrences following PVAI were common and should be considered when planning long-term AF patient management.

Dofetilide is safe and effective in preventing atrial fibrillation recurrences in patients accepted for catheter ablation.

AIMS: The aim of this study was to assess the safety and efficacy of dofetilide among patients refractory to other anti-arrhythmic drugs (AADs) and accepted for atrial fibrillation (AF) ablation. METHODS AND RESULTS: One hundred and twenty-seven of 454 patients (69% male, 58% paroxysmal, age 60 +/- 10 years, AF duration 8 +/- 7 years) scheduled for AF ablation between February 2004 and May 2008 were treated with dofetilide. Patients had failed 1.9 +/- 1.1 AADs. Anti-arrhythmic drugs were stopped five half-lives before ablation and 3 months for amiodarone. Patients were followed for 15 +/- 7 months with routine and symptom-driven monitoring. Success was defined as no further AF and partial success as a 50% reduction in frequency/duration of AF episodes. Thirty-six patients started dofetilide 158 +/- 167 days before ablation: 9 had no improvement, 16 experienced partial success, 8 had no further AF, and 2 improved enough to forgo ablation. Seventy-one patients started dofetilide immediately following ablation, of which 14 had no improvement, 22 experienced partial success, and 32 had no further AF. Twenty patients started dofetilide 119 +/- 153 days post-ablation, of which four had no improvement, seven experienced partial success, and nine had no further AF. Six patients discontinued dofetilide during initiation for QT prolongation. CONCLUSION: Dofetilide appears safe and effective in preventing AF in patients refractory to other AADs undergoing catheter ablation.

Real-time integration of 2D intracardiac echocardiography and 3D electroanatomical mapping to guide ventricular tachycardia ablation.

BACKGROUND: Ablation of left ventricular tachycardia (LV VT) involves point-by-point reconstruction of the three-dimensional (3D) virtual anatomy. It is time consuming and requires substantial fluoroscopy exposure. Two-dimensional (2D) intracardiac echocardiography (ICE) affords real-time imaging of the cardiac structures. OBJECTIVE: This study sought to evaluate a mapping system integrating ICE with 3D mapping to guide VT ablation. METHODS: Seventeen patients (16 men, 62 +/- 11 years, LV ejection fraction 40% +/- 15%) had ablation of nonidiopathic VT guided using a system integrating 3D mapping and ICE. ICE probe with a location sensor tracked by the mapping system was positioned in the right heart. Endocardial contours traced on gated images of the LV were used to generate a registered 3D map. Regional wall motion abnormalities (WMA) were tagged. RESULTS: 3D maps were created in 26 +/- 8 min, before entering the LV and without fluoroscopy. Maps were built from 23 +/- 7 contours. Regional WMA corresponded to low bipolar voltage (<0.5 mV). Procedure time was 240 +/- 77 min, with fluoroscopy time of 25 +/- 12 min. LV volume by ICE was 172 +/- 119 cm(3) versus 164 +/- 112 cm(3) for the point-by-point maps (P = .5). Scar area by ICE was 33 +/- 32 cm(2) versus 36 +/- 33 cm(2) for voltage mapping (P = .4). At 5 +/- 4 months, 12 patients (71%) were free of VT. CONCLUSION: A system combining 2D ICE and 3D mapping can reconstruct a 3D shell of the LV, including a substrate map based on regional WMA without the need to enter the LV. VT ablation guided using this approach is safe and effective.

Intracardiac ECHO Integration with Three Dimensional Mapping: Role in AF Ablation.

Background: Catheter ablation of atrial fibrillation (AF) is typically guided by 3D mapping. This involves point-by-point reconstruction of the 3D virtual anatomy and may be time consuming and require substantial fluoroscopy exposure. Intracardiac echocardiography (ICE) affords real time imaging of the cardiac structures during mapping and ablation. Methods: Between February and May 2007, 15 patients (100% men, 10 with paroxysmal AF) presenting for AF ablation were offered mapping using a novel system integrating 3D mapping and ICE. A modified ICE probe with a location sensor tracked by the mapping system was positioned in the right atrium (RA). This allowed acquisition of ECG gated images of the left atrium (LA). Endocardial contours were traced on each image and were used to generate a registered 3D map. Results: 3D maps took a mean of 51+/-25 minutes to create, PRIOR to entering the LA and without fluoroscopy. Pulmonary veins and the esophagus were rendered in 3D. A complete map was built from a mean of 46+/-19 contours. Upon instrumentation of the left atrium, the maps were easily distorted if points collected by the mapping catheter were combined with the original map, due to deformation of the left atrial geometry by the relatively stiff ablation catheter. Pulmonary vein antrum isolation was guided by a circular mapping catheter. Since this catheter could not be visualized on the CARTO map, fluoroscopy was used to track its position and the contact between the ablation catheter and the circular mapping catheter. No substantial reduction in fluoroscopy time was thus realized, as expected. At 10+/-1 months of followup, 73% of the patients were in sinus rhythm after the initial three month blanking period. No patient suffered any complications related to the procedure or in follow-up. Conclusions: A mapping system combining ICE and 3D electroanatomical mapping can feasibly reconstruct a 3D shell of the LA and the pulmonary veins without the need to enter the left heart. The map created is sensitive to distortion during point-by-point mapping with the standard ablation catheter.