Ablation of Rotor and Focal Sources Reduces Late Recurrence of Atrial Fibrillation Compared With Trigger Ablation Alone
Key result
FIRM-guided ablation is linked to doubled freedom from AF versus conventional ablation alone.
- P=0.001
- n=92
Why the study?
Late recurrence substantially limits the efficacy of pulmonary vein isolation for AF and is associated with reconnection and new triggers, raising the question of whether ablation targeting patient-specific substrates is more durable.
Does FIRM-guided ablation reduce late recurrence of atrial fibrillation compared to conventional ablation alone in patients with symptomatic AF?
Key Points
- To determine whether ablation targeting patient-specific sustaining substrates (rotors or focal sources) provides more durable prevention of late atrial fibrillation recurrence than trigger ablation alone.
- Follow-up at 3 years of 92 consecutive atrial fibrillation patients (70.7% persistent) in the prospective CONFIRM trial evaluated with computational mapping to detect sustaining rotors or focal sources.
- Patients received source ablation via Focal Impulse and Rotor Modulation followed by conventional ablation (FIRM-guided, n=27) or conventional trigger ablation alone (FIRM-blinded, n=65), with rhythm monitoring by implanted ECG monitors when possible (85.2% FIRM-guided vs 23.1% FIRM-blinded).
- At a median follow-up of 890 days (IQR 224–1563) after 1.2±0.4 procedures, freedom from atrial fibrillation was higher in the FIRM-guided group than the conventional group (77.8%, 21/27 vs 38.5%, 25/65; p=0.001).
- Freedom from any atrial tachyarrhythmias after 1.2±0.4 procedures remained higher with FIRM-guided ablation compared to conventional therapy (70.4%, 19/27 vs 36.9%, 24/65; p=0.003).
- Single-procedure freedom from atrial fibrillation was also significantly higher with FIRM-guided ablation across all patients (66.7%, 18/27 vs 27.7%, 18/65; p<0.001) and in patients undergoing a first ablation (75.0%, 15/20 vs 30.2%, 16/53; p<0.001).
Study Design
Type
Cohort (n=92)
Multicenter
Yes
Structured PICO
Does FIRM-guided ablation reduce late recurrence of atrial fibrillation compared to conventional ablation alone in patients with symptomatic AF?
P
Population
92 patients with symptomatic atrial fibrillation (70.7% persistent) referred for ablation, followed for a median of 890 days.
I
Intervention
FIRM-guided ablation (targeted ablation of patient-specific AF sources followed by conventional ablation)
C
Comparator
Conventional ablation alone (wide area circumferential ablation of left and right PV pairs, plus left atrial roof line in persistent AF)
O
Outcome
Freedom from AF (<1% burden on continuous implanted ECGs or <30 seconds on quarterly monitors) at median 890 days follow-uphard clinical
Main Result
Absolute Event Rate: 77.8% vs 38.5%
p-value: p=0.001
Limitations
- Non-randomized design
- Differences in baseline characteristics between groups (more persistent AF and comorbidities in FIRM group)
- Higher prevalence of implanted loop recorders in FIRM-guided group
- Small sample size
- Protocol did not standardize ablation of the cavotricuspid isthmus
- Non-randomized
- Baseline differences between groups
Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“We are very excited by this trial, which for the first time shows that atrial fibrillation is maintained by small electrical hotspots, where brief FIRM guided ablation can shut down the arrhythmia and bring the heart back to a normal rhythm after only minutes of ablation.”
“The results of this trial, with an 80 percent ablation success rate after a single procedure, are very gratifying. This is the dawn of a new phase of managing this common arrhythmia that is mechanism-based.”
JBJohannes BrachmannElectrophysiologist, Klinikum Coburg GmbH
“The treatment arm, while it is not what we anticipated in 2014, does fall in line with single centre reports. The control arm is somewhat surprising, in that it is better than anticipated.”
Implication
Ablation of patient-specific AF-sustaining rotors and focal sources in addition to conventional ablation significantly improves long-term freedom from AF.
Abstract
Objectives To determine if ablation that targets patient-specific AF-sustaining substrates (rotors or focal sources) is more durable than trigger ablation alone at preventing late AF recurrences. Background Late recurrence substantially limits the efficacy of pulmonary vein (PV) isolation for AF, and is associated with PV reconnection and the emergence of new triggers. Methods We performed 3 year follow-up of the CONFIRM trial, in which 92 consecutive AF patients (70.7% persistent) underwent novel computational mapping to reveal a median of 2 (IQR 1–2) rotors or focal sources in 97.7% of patients during AF. Ablation comprised source (Focal Impulse and Rotor Modulation, FIRM) then conventional ablation in n=27 (FIRM-guided), and conventional ablation alone in n=65 (FIRM-blinded). Patients were followed with implanted ECG monitors when possible (85.2% FIRM guided, 23.1% FIRM-blinded). Results On 890 days follow-up (median; IQR 224–1563) compared FIRM-blinded therapy, patients receiving FIRM-guided ablation maintained higher freedom from AF after 1.2±0.4 procedures (median 1, IQR 1–1) (77.8% vs 38.5%; p=0.001) and a single procedure (p>0.001), and higher freedom from all atrial arrhythmias (p=0.003). Freedom from AF was higher when ablation directly or coincidentally passed through sources than when it missed sources (p>0.001). CONCLUSIONS FIRM-guided ablation is more durable than conventional trigger-based ablation at preventing 3 year AF recurrence. Future studies should investigate how ablation of patient-specific AF-sustaining rotors and focal sources alters the natural history of arrhythmia recurrence.
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Cite This Study
Narayan et al. (2014) conducted a cohort in Atrial fibrillation (n=92). FIRM-guided ablation vs. Conventional ablation alone was evaluated on Freedom from AF (p=0.001). FIRM-guided ablation maintained higher freedom from AF compared to conventional ablation alone (77.8% vs 38.5%, p=0.001) over a median follow-up of 890 days.