A personalized heart ablation strategy substantially improved rhythm control in selected patients with persistent atrial fibrillation, according to a randomized clinical trial published August 30, 2026, in JAMA.
The IDEAL-AF trial found that targeted ablation of significant low-voltage atrial areas improved 12-month rhythm outcomes when added to pulmonary vein isolation in selected patients with persistent atrial fibrillation.
The IDEAL-AF trial tested whether doctors could improve standard pulmonary vein isolation by identifying abnormal low-voltage areas in the left atrium and targeting those areas with additional ablation.
Among 209 patients with significant low-voltage zones, 67.6% of those receiving targeted ablation plus pulmonary vein isolation were free from documented atrial arrhythmias without antiarrhythmic drugs at 12 months, compared with 37.4% receiving pulmonary vein isolation alone.
The 30.3 percentage-point difference is substantial. However, the result applies to a carefully selected group of patients and does not mean that performing more ablation is better for everyone with atrial fibrillation.
Key Takeaways
- Researchers performed pulmonary vein isolation and voltage mapping in 936 patients with persistent or long-standing persistent atrial fibrillation.
- Only 209 had significant low-voltage zones and were randomized.
- At 12 months, 67.6% receiving targeted ablation plus pulmonary vein isolation met the primary rhythm outcome, compared with 37.4% receiving pulmonary vein isolation alone.
- After only one ablation procedure, the corresponding figures were 62.7% and 31.8%.
- Serious adverse events occurred in 9.8% versus 7.5%, a difference that was not statistically significant.
- A previous major trial, DECAAF II, found no significant benefit from adding MRI-guided fibrosis ablation, suggesting that patient selection and the method used to identify abnormal tissue may be important.
What Did the IDEAL-AF Trial Test?
Pulmonary vein isolation, or PVI, is a foundational catheter ablation treatment for atrial fibrillation. It electrically isolates the pulmonary veins, which are an important source of abnormal electrical activity that can trigger AF.
Persistent atrial fibrillation can be more difficult to treat because abnormal electrical and structural changes outside the pulmonary veins may also help maintain the arrhythmia.
In the new IDEAL-AF randomized clinical trial, Paul Nordin et al. (2026) investigated whether identifying and targeting this additional abnormal tissue could improve outcomes.
The study was conducted at five Swedish ablation centers. Of 936 adults undergoing their first ablation and voltage mapping for persistent or long-standing persistent AF, 209 had significant low-voltage zones covering at least 3 cm².
Those patients were randomized after PVI. A total of 102 received additional individualized ablation targeting their low-voltage zones, while 107 received PVI alone. The median age was 72 years, and 52.2% were women.
Targeted Ablation Produced a Large Difference
The trial’s primary outcome was freedom from documented atrial fibrillation, atrial flutter, or atrial tachycardia lasting more than 30 seconds at 12 months without antiarrhythmic medication.
The outcome was achieved by 67.6% of patients receiving PVI plus targeted low-voltage-zone ablation compared with 37.4% receiving PVI alone.
That represented an absolute difference of 30.3 percentage points, with a 95% confidence interval of 17.4 to 43.2 percentage points. The odds ratio was 3.5.
There is an important qualification. The primary endpoint allowed patients to undergo a second ablation within six months, so 67.6% versus 37.4% should not be interpreted as the success rate of a single procedure.
However, results after a single procedure also strongly favored targeted treatment. 62.7% of patients receiving additional low-voltage ablation remained free from documented atrial arrhythmia without antiarrhythmic drugs, compared with 31.8% receiving PVI alone.
Why This Result Is More Interesting Than It First Appears
Researchers have previously tried several approaches to treating abnormal atrial tissue beyond the pulmonary veins, but randomized trials have produced conflicting results.
A particularly important comparison is the DECAAF II randomized clinical trial by Marrouche et al. (2022), which included 843 patients with persistent atrial fibrillation.
The researchers tested a different personalized strategy, using delayed-enhancement cardiac MRI to identify areas of atrial fibrosis and comparing PVI plus MRI-guided fibrosis ablation with PVI alone.
Unlike IDEAL-AF, DECAAF II did not demonstrate a significant improvement.
Atrial arrhythmia recurrence occurred in 43.0% of patients receiving fibrosis-guided ablation and 46.1% receiving PVI alone. The hazard ratio was 0.95, indicating no statistically significant reduction in recurrence.
DECAAF II also raised safety concerns. Its predefined composite safety outcome occurred in 2.2% of patients receiving fibrosis-guided ablation and none of those receiving PVI alone. Six patients in the fibrosis-guided group experienced ischemic stroke compared with none in the PVI-only group.
Why Might IDEAL-AF Have Produced a Different Result?
The two trials cannot be directly compared as though they tested the same treatment, but their differences are informative.
First, they identified abnormal tissue differently.
DECAAF II used cardiac MRI to identify atrial fibrosis. IDEAL-AF used electrical voltage mapping performed during the ablation procedure. These methods may identify overlapping but not identical characteristics of abnormal atrial tissue.
Second, patient selection differed substantially.
IDEAL-AF did not automatically apply additional ablation to everyone with persistent AF. Researchers first mapped 936 patients and randomized only the 209 who had significant low-voltage zones.
The additional ablation was also individualized according to the location and pattern of each patient’s abnormal tissue.
This raises an important possibility: the benefit may depend less on simply performing more ablation and more on identifying which patients have abnormal tissue suitable for additional treatment.
IDEAL-AF does not prove that voltage mapping is superior to MRI-guided fibrosis mapping. The trials involved different populations, procedures and treatment strategies and were not designed as a head-to-head comparison.
Their contrasting findings do, however, suggest that patient selection and the method used to identify abnormal atrial tissue could be important.
What About Safety?
Serious adverse events occurred in 9.8% of patients receiving targeted low-voltage-zone ablation and 7.5% receiving PVI alone. The difference was not statistically significant.
One patient in the PVI-only group died following a major stroke considered possibly related to the procedure.
The trial was too small to establish whether uncommon complications differ between the two strategies. The absence of a statistically significant safety difference therefore should not be interpreted as proof that additional ablation is equally safe.
Additional treatment also increased procedure, ablation and fluoroscopy times.
Does This Change Treatment for Everyone With Persistent AF?
No.
Only about 22% of the 936 mapped patients had low-voltage zones large enough to qualify for randomization.
The results therefore apply specifically to selected patients with persistent or long-standing persistent AF undergoing first-time radiofrequency ablation who have significant low-voltage areas identified during mapping.
The study also used radiofrequency ablation, so the findings cannot automatically be extended to newer approaches such as pulsed-field ablation.
Another limitation is the length of follow-up. Patients were followed for only 12 months, leaving uncertainty about whether the difference will persist over several years.
Rhythm monitoring was not continuous, meaning some asymptomatic episodes could have gone undetected. Physicians performing the procedures also could not be blinded to treatment assignment.
What Does the Evidence Actually Tell Us?
IDEAL-AF provides randomized evidence that a more individualized strategy can substantially improve short-term rhythm control in selected patients with persistent atrial fibrillation and significant low-voltage zones.
The comparison with DECAAF II makes the finding more consequential. Previous attempts to target atrial abnormalities beyond the pulmonary veins have not consistently improved outcomes.
IDEAL-AF suggests the answer may not simply be to ablate more heart tissue. Instead, identifying the right patients and targeting the right abnormal tissue may be what matters.
Whether the benefit remains after several years, can be reproduced in other centers, and remains relevant as newer ablation technologies become more common will require further research.
References
Paul Nordin, A., Charitakis, E., Carnlöf, C., et al. (2026). Low-voltage ablation in persistent atrial fibrillation: The IDEAL-AF randomized clinical trial. JAMA. Advance online publication. https://doi.org/10.1001/jama.2026.17274
Marrouche, N. F., Wazni, O., McGann, C., et al. (2022). Effect of MRI-guided fibrosis ablation vs conventional catheter ablation on atrial arrhythmia recurrence in patients with persistent atrial fibrillation: The DECAAF II randomized clinical trial. JAMA, 327(23), 2296–2305. https://doi.org/10.1001/jama.2022.8831
