An interventional study of Conventional AF Ablation with PVI and FIRM-guided ablation plus PVI in Atrial Fibrillation, sponsored by Stanford University. Completed at 2 sites in United States. Open to participants aged 22 Years and older. Per ClinicalTrials.gov, last updated 2025-03-04.
Sponsored by Stanford University · Not applicable, Interventional, and Treatment
This prospective randomized study will assess the safety and efficacy of FIRM-guided ablation (FIRM+PVI) compared to pulmonary vein isolation (PVI) without FIRM, for the treatment of symptomatic atrial fibrillation.
Atrial fibrillation (AF) affects over 2 millions Americans. AF may reduce cardiac performance and may result in thrombus formation in the left atrium and thromboembolic events, such as stroke. Ablation to eliminate the causes of this arrhythmia is increasingly performed since pharmacological therapy is suboptimal. Ablation currently targets triggers, by ablating left atrial areas outside the pulmonary veins (pulmonary vein isolation, PVI) in subjects with symptomatic AF who have failed drugs. Unfortunately, this has mixed success with the best outcomes being 50-70% freedom from AF at 1 year post ablation.
A major issue with AF therapy is the lack of knowledge about critical regions of the heart that cause and sustain AF. A recent trial (STAR-AF2) showed that ablating regions empirically - i.e. without defining their role in AF(lines or fractionated electrograms) - did not improve patient outcomes compared to PVI alone (Verma et al, NEJM 2015). However, this leaves us with PVI that had a 50% success rate in that trial and in several other trials even for paroxysmal AF.
We hypothesize that guiding ablation to critical arrhythmia-targeting zones will improve success over PVI alone. Specifically, we hypothesize that computational mapping of AF will find small regions called rotors and focal sources and ablate them, called Focal Impulse and Rotor Modulation (FIRM) ablation, shows promise at eliminating AF substrates. In many single center trials, FIRM improves results from PVI alone. This will be among the first randomized comparisons of FIRM ablation compared to PVI alone, and addresses an important question in the field.
3,870 studies on the registry are indexed under Atrial Fibrillation; 923 are open to participants now.
This study's enrollment of 84 is below the median of 144 across 2,380 interventional studies indexed under Atrial Fibrillation.
Browse Atrial Fibrillation studies →Stanford University is the lead sponsor of 2,117 studies on the registry; 425 are open to participants now.
Of its 259 completed or terminated interventional studies of FDA-regulated products, 197 (76%) have results posted.
Counted across the registry records on this site, refreshed daily.
Oral anticoagulation required for those subjects who have a score of two or more based on the following criteria (CHA2DS2VASc)
Exclusion Criteria:
Structural heart disease of clinical significance including:
These patients will be treated by conventional AF ablation by pulmonary vein isolation (PVI) alone.
Procedure: Conventional AF Ablation with PVI
These patients will be treated by ablation of patient-specific rotors and focal sources (FIRM). Conventional ablation (PVI) will then be performed as part of the standard of care procedure.
Procedure: FIRM-guided ablation plus PVI
Trigger Based Ablation for AF, using Pulmonary Vein Isolation (PVI) alone
Substrate ablation for AF, via ablation of rotors and focal sources. Conventional (PVI) ablation will also be performed.
Long term success
Freedom from atrial fibrillation (AF) recurrence during the 12 months after the initial AF ablation procedure, after an initial 3 month blanking (healing and stabilization) period.
Time frame: 12 months
Long-term freedom from AF/AT
Freedom from AF and atrial tachycardia (AT) during the 12 months after the initial AF ablation procedure, after an initial 3 month blanking (healing and stabilization) period. Atrial tachycardias (AT) include those arising from atrial regions where ablation was performed (such as left atrial tachycardia) as well as from regions where ablation was not performed (such as typical cavotricuspid isthmus dependent atrial flutter).
Time frame: 12 months
Total ablation time
Total ablation time will be recorded in all patients, measured as the cumulative application of energy from the first ablation lesion to the last lesion. These values will be compared between the FIRM-guided and conventional ablation groups. If ablation for AT/atrial flutter is pursued, this ablation time will be documented separately.
Time frame: 1 day
Quality of Life (comparing post-ablation to pre-ablation)
Quantitative EuroQol EQ5D scores post-ablation will be compared to those pre-ablation at all time points separately and together (ANOVA)
Time frame: 12 months
Adverse Events
Adverse events will be adjudicated by an independent Data and Safety Monitoring Committee, who will determine whether they are or are not related to the procedure. The number and type of adverse events will be compared between FIRM-guided and conventional ablation groups.
Time frame: 12 months
Healthcare Utilization
Hospitalization, other procedures and healthcare utilization, adjudicated by an independent Data and Safety Monitoring Committee, will be compared between limbs.
Time frame: 12 months
Documents are hosted by the registry — open the source record to download them.
This study is completed, as verified in Feb 2025. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Stanford University