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The cognitive deficits that may emerge after catheter ablation for atrial fibrillation (Afib) appeared short-lived in a small randomized trial, providing some reassurance.

Cognitive testing showed that postoperative cognitive dysfunction (POCD) was present at 3 months in 14% of people who underwent ablation versus 2% of peers sticking to medical therapy alone (P=0.03), according to Jonathan Kalman, MBBS, PhD, of Royal Melbourne Hospital in Australia, and colleagues.

By 6 months, the difference between groups had narrowed to insignificance (4% vs 2%), and by 12 months, even favored the ablation group numerically (0% vs 2%) as no patients in the medical arm had improved cognition over time, investigators reported in .

"POCD was observed following AF [Afib] ablation. However, this was transient with complete recovery at 12-month follow-up," Kalman's group concluded. "We believe this data provides reassurance regarding the impact of catheter ablation on cognitive function."

Kalman and colleagues reported that ablation time was the only significant multivariable predictor of new-onset cognitive dysfunction (OR 1.30, 95% CI 1.01-1.60).

Afib has been linked to long-term cognitive and memory problems independent of stroke, with multifactorial factors including silent cerebral infarction, cerebral hypoperfusion, and microbleeds.

Separately, it is thought that postablation cognitive dysfunction may be caused by anesthesia or silent cerebral embolic lesions stemming from procedure. "The etiology of POCD following catheter ablation is multifactorial and remains incompletely explained," study authors noted.

They nevertheless cited a recent study showing silent brain embolic events commonly found on cardiac MRI have no bearing on cognitive function deterioration, which suggests that POCD is not solely caused by these imaging findings.

Kalman and colleagues themselves lacked preablation and postablation MRI scans to assess any relationship between cognitive outcomes and silent cerebral embolic lesions.

The investigators conducted their randomized trial at two tertiary hospitals in Australia, enrolling individuals with symptomatic paroxysmal or persistent Afib who failed at least one antiarrhythmic drug (AAD). Out of 100 people enrolled, 96 completed the study (mean age 59, 32% women) after being randomized to usual medical therapy or catheter ablation with encouragement of uninterrupted oral anticoagulation.

All 49 participants in the ablation arm had successful pulmonary vein isolation; of those, one in five received additional ablation.

Investigators assessed POCD with regular assessments by six cognitive tests:

• Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Auditory Verbal Learning Test
• CERAD Semantic Fluency Test
• (TMT) Part A
• TMT Part B

Overall, patients in the ablation group experienced significant improvements in their cognitive scores compared with the medical arm at both 3 months and 12 months -- correlating with reduced Afib burden and lower need for AADs as well, Kalman and co-authors reported.

"We postulate that improved hemodynamic control accompanied by cessation of AADs may be important contributors to early improvements in cognitive function. Certainly, the use of AADs among patients who experienced cognitive improvement was significantly lower compared with patients who did not demonstrate improvement in cognitive testing," they stated.

The authors acknowledged that long-term follow-up over 5 and/or 10 years would be necessary to really show cognitive benefits to catheter ablation, if any, over conservative therapy alone for Afib.

Recently, another group had reported results from a prospective observational study showing a lower risk of cognitive impairment at 2 years among Afib patients with a history of radiofrequency catheter ablation, compared with those managed with drugs alone.

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