72 * Contact force timing reduces pulmonary vein reconnection, early results from the smart AF trial

Abstract

Introduction: The addition of contact force (CF) sensing information may facilitate wide area circumferential ablation (WACA). We present data from an interim analysis of the first multicentre randomised controlled trial studying the impact of (CF) sensing information on the ablation of paroxysmal atrial fibrillation (AF). Method: At 7 UK centres, patients undergoing first time paroxysmal AF ablation were randomised to ablation with or without CF data available to the operator. The planned recruitment is 120 patients with 1 year follow up. Using a 3D mapping system and the SmartTouch CF-sensing catheter (Biosense Webster), all patients underwent WACA. Following this, a wait time of 60 minutes was observed before checking for acute electrical pulmonary vein (PV) reconnection. If the PV remained isolated at 60 minutes 18mg adenosine was administered intravenously. The primary end point was acute PV reconnection whether spontaneous or adenosine induced. Each PV was assessed separately, though in cases of a common trunk these were taken as one vein. Where procedures were terminated prematurely for whatever reason, PVs that remained isolated but had not completed the 1 hour waiting period were excluded from the analysis of acute PV reconnection. Follow up is ongoing and outcomes are not reported here. Results: Currently, 91 of 120 patients have been recruited (44 randomised to blinded group, 47 to unblinded group). The mean age was 59±10years, 52.7% male, CHA2DS2VASC 1.5±1.6, duration of AF 36 (6-289) months. There were no significant differences in baseline characteristics between groups. There were no significant differences in the procedural parameters for the procedures as a whole (Table) or for the same parameters for each PV pair separately (p>0.05). There was a significant reduction in the proportion of pulmonary veins that reconnected acutely in the unblinded group, and this was driven by a reduction in left sided reconnections (Table). There were two tamponades and one minor pericardial effusion, all in the unblinded arm (p=0.24). Conclusion: Based on our interim analysis, addition of contact force sensing data had no impact on procedure time, fluoroscopy use, or the amount of ablation used, but did reduce the rate of acute pulmonary vein reconnection suggesting more effective application of ablation lesions. Whether this translates to improved success rates will be assessed on completion of the study. | | CF Blinded Group | CF Unblinded Group | p-value | | ------------------------------------------------ | ---------------- | ------------------ | ------- | | Total Procedure Time in mins | 196(127-310) | 193 (125-337) | 0.7 | | Total Fluoroscopy Time in mins | 13 (1-54) | 10 (1-60) | 0.9 | | Total Fluoroscopy Dose in cGy.cm2 | 947 (98-47000) | 826 (48-42860) | 0.9 | | Total Radiofrequency Ablation Time in seconds | 2289 (977-4420) | 2446 (1262-5571) | 0.2 | | Total Pulmonary Vein Reconnections at 60 minutes | 48/173 (28%) | 31/172 (18%) | 0.04 | | Left Pulmonary Vein Reconnections at 60 minutes | 28/88 (32%) | 12/87 (14%) | 0.0065 | | Right Pulmonary Vein Reconnections at 60 minutes | 20/85 (24%) | 19/85 (22%) | 1 |