FIRM-guided ablation improved both the acute endpoint of AF termination or slowing (86% vs 20%) and long-term freedom from AF (82.4% vs 44.9%, p<0.001) compared to conventional ablation alone.
RCT (n=92)
Blinded
Does FIRM-guided ablation followed by conventional ablation improve freedom from AF compared to conventional ablation alone in patients with paroxysmal or persistent atrial fibrillation?
FIRM-guided ablation targeting localized sources acutely terminated or slowed AF and significantly improved long-term freedom from AF compared to conventional ablation alone.
Absolute Event Rate: 86% vs 20%
p-value: p=<0.001
Objectives We hypothesized that human atrial fibrillation (AF) may be sustained by localized sources (electrical rotors and focal impulses), whose elimination (Focal Impulse and Rotor Modulation, FIRM) may improve outcome from AF ablation. Background Catheter ablation for AF is a promising therapy, whose success is limited in part by uncertainty in the mechanisms that sustain AF. We developed a computational approach to map whether AF is sustained by several meandering waves (the prevailing hypothesis) or localized sources, then prospectively tested whether targeting patient-specific mechanisms revealed by mapping would improve AF ablation outcome. Methods We recruited 92 individuals during 107 consecutive ablation procedures for paroxysmal or persistent (72%) AF. Cases were prospectively treated, in a 2-arm 1:2 design, by ablation at sources (FIRM-Guided) followed by conventional ablation (n=36), or conventional ablation alone (n=71; FIRM-Blinded). Results Localized rotors or focal impulses were detected in 98 (97%) of 101 cases with sustained AF, each exhibiting 2.1±1.0 sources. The acute endpoint (AF termination or consistent slowing) was achieved in 86% of FIRM-guided versus 20% of FIRM-Blinded cases (p<0.001). FIRM ablation alone at the primary source terminated AF in 2.5 minutes (median; IQR 1.0–3.1). Total ablation time did not differ between groups (57.8±22.8 versus 52.1±17.8 minutes, p=0.16). During 273 days (median; IQR 132–681 days) after a single procedure, FIRM-Guided cases had higher freedom from AF (82.4% versus 44.9%; p<0.001) after a single procedure than FIRM-blinded cases with rigorous, often implanted, ECG monitoring. Adverse events did not differ between groups. CONCLUSIONS Localized electrical rotors and focal impulse sources are prevalent sustaining-mechanisms for human AF. FIRM ablation at patient-specific sources acutely terminated or slowed AF, and improved outcome. These results offer a novel mechanistic framework and treatment paradigm for AF. (ClinicalTrials.gov number, NCT01008722)
Narayan et al. (Wed,) conducted a rct in Paroxysmal or persistent atrial fibrillation (n=92). FIRM-guided ablation (ablation at sources followed by conventional ablation) vs. Conventional ablation alone was evaluated on Acute endpoint (AF termination or consistent slowing) (p=<0.001). FIRM-guided ablation improved both the acute endpoint of AF termination or slowing (86% vs 20%) and long-term freedom from AF (82.4% vs 44.9%, p<0.001) compared to conventional ablation alone.