Soleil Research™ | Evidence Review
Can individualized ablation of abnormal atrial substrate improve rhythm control beyond pulmonary vein isolation in persistent atrial fibrillation?
The IDEAL-AF randomized clinical trial, published online in JAMA on August 30, 2026, tested that question in a carefully selected group of patients with persistent atrial fibrillation and significant left atrial low-voltage zones identified during first-time radiofrequency ablation.
Plain-Language Summary
In 209 adults with persistent atrial fibrillation and significant left atrial low-voltage zones, adding individualized low-voltage zone ablation to standard pulmonary vein isolation improved the chance of being free from documented atrial arrhythmia without antiarrhythmic drugs at 12 months after one or two ablation procedures. The primary outcome occurred in 67.6% of patients assigned to pulmonary vein isolation plus low-voltage zone ablation compared with 37.4% assigned to pulmonary vein isolation alone.
The additional ablation required longer and more complex procedures. Serious adverse events were not statistically different between groups, but the trial was not large enough to determine whether uncommon complications differ between strategies. These results apply to the selected population studied and should not be generalized to all patients with persistent atrial fibrillation or to newer pulsed-field ablation technologies.
Why This Study Matters
Pulmonary vein isolation is the foundation of catheter ablation for atrial fibrillation, but outcomes in persistent atrial fibrillation remain less predictable than in paroxysmal disease. One proposed reason is that some patients have additional abnormal atrial substrate outside the pulmonary veins.
IDEAL-AF tested a precision-oriented strategy: identify significant left atrial low-voltage zones during mapping and ablate them only in patients who actually have that substrate. The study therefore does not test a universal “more ablation is better” approach. It tests whether substrate-guided treatment adds benefit in a preselected population.
What the Study Tested
IDEAL-AF was an investigator-initiated, multicenter, single-blind randomized clinical trial conducted at five Swedish ablation centers. Among 936 patients undergoing pulmonary vein isolation and voltage mapping for persistent atrial fibrillation, 209 with at least one significant low-voltage zone of 3.0 cm² or greater outside the pulmonary vein isolation lines were randomized after pulmonary vein isolation.
- PVI plus individualized low-voltage zone ablation: 102 patients.
- PVI alone: 107 patients.
The median age was 72 years, and 52.2% of randomized participants were women.
The prespecified primary endpoint was freedom from documented atrial fibrillation, atrial flutter, or atrial tachycardia lasting more than 30 seconds, without antiarrhythmic drugs, at 12 months after one or two ablation procedures. A repeat procedure was permitted within six months and had to follow the originally assigned strategy.
Primary Result
The primary endpoint was achieved by 69 of 102 patients (67.6%) in the low-voltage zone ablation group and 40 of 107 patients (37.4%) in the pulmonary vein isolation-alone group.
- Absolute difference: 30.3 percentage points (95% CI, 17.4–43.2).
- Odds ratio: 3.5 (95% CI, 2.0–6.2).
- P value: <.001.
Time to first recurrence after a single procedure without antiarrhythmic drugs also favored adjunctive low-voltage zone ablation, with a hazard ratio of 0.4 (95% CI, 0.3–0.6; P<.001).
The consistency of the single-procedure recurrence analysis is important because it reduces concern that the primary result was driven only by the option to perform a second procedure.
Quality of Life and Safety
Health-related quality of life improved more with adjunctive low-voltage zone ablation. At the same time, the more extensive strategy required longer procedure, ablation, and fluoroscopy times.
Serious adverse events occurred in 10 of 102 patients (9.8%) in the low-voltage zone ablation group and 8 of 107 patients (7.5%) in the pulmonary vein isolation-alone group (P=.48).
That non-significant difference should not be interpreted as proof of equivalent safety. IDEAL-AF was not powered to determine whether uncommon serious complications differ between strategies.
Methodological Quality
Soleil Research assessment: HIGH — strong randomized multicenter evidence for a narrowly defined clinical population.
Randomization, concealed allocation, multicenter enrollment, prospective registration, a prespecified clinically meaningful endpoint, intention-to-treat analysis, blinded rhythm-recording assessment, and prespecified sensitivity analyses strengthen internal validity. Patients were blinded to treatment assignment, although procedural operators could not be blinded.
The trial also used a selection strategy aligned with the biological target of the intervention: patients were randomized only if mapping identified significant low-voltage substrate. This improves the specificity of the causal question but narrows generalizability.
Strengths
- Randomized multicenter design with concealed allocation.
- Prospective trial registration and published protocol.
- Enrollment targeted the atrial substrate the intervention was designed to treat.
- Clinically meaningful rhythm endpoint assessed without antiarrhythmic drugs.
- Intention-to-treat analysis with conservative handling of missing primary-outcome data.
- Single-procedure recurrence analysis supported the primary finding.
- Health-related quality of life was evaluated in addition to rhythm outcomes.
Limitations and Cautions
- Operator blinding was impossible: electrophysiologists necessarily knew which ablation strategy they were performing.
- Low voltage is a surrogate: bipolar voltage mapping is used as a marker of abnormal atrial substrate but is not direct histopathological measurement of fibrosis.
- Procedural heterogeneity: the individualized strategy was intentionally adapted to each patient's low-voltage distribution, so lesion sets were not identical across participants.
- Mapping uncertainty: septal low-voltage areas can be overestimated when tissue contact is suboptimal.
- Intermittent monitoring: smartphone ECG and Holter-based surveillance can miss asymptomatic arrhythmia recurrence compared with continuous implanted monitoring.
- Safety precision: the trial was not powered for rare adverse events.
- Duration: the primary endpoint was measured at 12 months, leaving longer-term durability uncertain.
- Technology: only radiofrequency ablation was studied; pulsed-field ablation was not evaluated.
- Generalizability: the findings apply to first-time ablation patients with persistent atrial fibrillation, significant low-voltage zones, and the ability to maintain sinus rhythm after pulmonary vein isolation and cardioversion. They should not be extrapolated automatically to patients without this substrate.
Funding and Conflicts of Interest
The trial received support from the Swedish Research Council, Swedish Heart-Lung Foundation, Center for Innovative Medicine, ALF Stockholms Läns Landsting, and Åke Wibergs Stiftelse. Coala Solutions AB provided monitoring devices. According to the publication, the funders and other supporters had no role in trial design or conduct, data collection or analysis, interpretation, manuscript preparation, or the decision to submit the work for publication.
Several authors disclosed relationships with electrophysiology device and pharmaceutical companies, including speaking fees, consulting, proctoring, institutional lecture fees, committee work, and research support involving companies such as Johnson & Johnson MedTech, Abbott, Medtronic, Boston Scientific, Biotronik, AstraZeneca, and Bristol Myers Squibb/Pfizer. These disclosures are relevant to transparency but do not, by themselves, invalidate a randomized result.
Soleil Insight
Personalized substrate-guided ablation improved rhythm control in a carefully selected population, but the result should not be generalized to every patient with persistent atrial fibrillation—or to newer ablation technologies—without further evidence.
IDEAL-AF is important not because it establishes a universal rule that more ablation is better, but because it tested an intervention only in patients who had the substrate it was designed to target. The next questions are durability, external replication, rare safety outcomes, and whether similar substrate-guided selection adds value in the era of pulsed-field ablation.
Bottom Line
For patients undergoing first-time radiofrequency ablation for persistent atrial fibrillation who had significant left atrial low-voltage zones, adding individualized low-voltage zone ablation to pulmonary vein isolation substantially improved 12-month rhythm outcomes compared with pulmonary vein isolation alone. The evidence is strong for this selected population, while broader applicability and long-term safety and durability remain open questions.
Original Publication
Paul Nordin A, Charitakis E, Carnlöf C, et al. Low-Voltage Ablation in Persistent Atrial Fibrillation: The IDEAL-AF Randomized Clinical Trial. JAMA. Published online August 30, 2026. DOI: 10.1001/jama.2026.17274.
Trial registration: NCT04377594
Published protocol: IDEAL-AF trial rationale and design. European Heart Journal Open. 2025. DOI: 10.1093/ehjopen/oeaf037.
Featured Image Attribution
Featured image: “Atrial Fibrillation” by BruceBlaus, via Wikimedia Commons, licensed under CC BY-SA 4.0. The educational illustration does not depict an IDEAL-AF participant or trial procedure.
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