
July 7, 2025 — Catheter ablation is a minimally invasive treatment for abnormal heart rhythms. It is often successful in treating various forms of heart rhythm disturbances, including atrial fibrillation (A-fib), but the procedure is associated with visual auras of flashes, flickering lights, or blind spots, similar to the ones seen by people who experience migraine headaches.
These visual phenomena are attributed to a temporary hole formed during the procedure — a transseptal puncture — between the right and left atria. Similarly, migraines have been associated with a small hole in the same location, also known as patent foramen ovale. Researchers from UC San Francisco set out to better understand the relationship between such a hole and visual auras as a result of catheter ablation and found that small brain injuries in the visual cortex of the brain following the procedure were associated with these visual aura symptoms.
Their results appeared July 7 in Heart Rhythm.
Past research had suggested that these small holes between the atria allow for shunting of an unknown chemical that goes directly from the venous circulation to the left-sided circulation (and therefore to the brain) that usually would be metabolized by the lungs. Another possible explanation suggests that the hole allows passage of small blood clots that form in veins of the legs and then block blood flow to small areas of the brain.
In the current trial, patients were randomly assigned to two types of catheter ablation for ventricular arrhythmias. One approach was achieved by a transseptal puncture (creating a new, temporary hole between the left and right atria) and the other by a retrograde approach through the aortic valve, not requiring a transseptal puncture.
The day after the procedure, the researchers obtained brain MRIs for all patients in both groups. Both procedures are known to result in small brain lesions which could be seen on the MRIs the next day. Interestingly, while there was no evidence of a relationship between transseptal punctures (or the retrograde approach) and the incidence of these visual auras, the researchers did find a relationship between new brain lesions in the occipital and parietal lobes of the brain and the occurrence of these visual aura symptoms when the patients were checked for migraines one month after the procedure.
New Approach for Migraine Care
“Those patients with migraine-related visual auras were significantly more likely to exhibit an acute brain embolism in their occipital or parietal lobes attributed to the procedure,” said study senior author Gregory M. Marcus, MD, MAS, a cardiologist and director of clinical research at the UCSF division of Cardiology. “These data suggest that visual auras that commonly occur with migraines may actually signal brain injury or little strokes. This finding could change the whole paradigm of treatment, perhaps focusing more on prevention of blood clots.”
While these brain lesions occurred immediately after these procedures, they could often not be seen when brains were imaged a month later when patients reported having visual aura, migraine-type symptoms.
“We know that these brain lesions are seen after very common procedures, including after coronary angiograms, after transcutaneous replacement of aortic valves (TAVRs), after ablations for atrial fibrillation and ventricular arrhythmias and are often referred to ‘ACEs’ – asymptomatic cerebral emboli,” said Adi Elias, MD, UCSF cardiac electrophysiology fellow and first author of the study. “Our data shows they are not asymptomatic or clinically silent. It may be the case that we haven’t known what to look for and assessed for symptoms immediately without enough time for the subsequent visual auras that would occur.”
The authors note that while this finding may be broadly applicable to patients suffering from migraines, the study population itself was focused on those undergoing catheter ablation of ventricular arrhythmias.
For more information, please visit www.ucsfhealth.org.
Additional UCSF Authors: Adi Elias, MD, MPH, Edward P. Gerstenfeld, MD, MS, FHRS, Trisha F. Hue, PhD, MPH, Feng Lin, MS, Jing Cheng, MD, PhD, Henry Hsia, MD, FHRS, Adam Lee, MBBS, Joshua Moss, MD, FHRS, Gabrielle Montenegro, Anthony S. Kim, MD, MS, William P. Dillon, MD. For complete list of authors, see the paper.
Funding: This trial was funded by Comparative Effectiveness Research grant 2017C3-9091 from the Patient Centered Outcomes Research Institute.
Disclosures: Dr. Marcus is a consultant for and owns equity in InCarda and receives research funding from the National Institutes of Health and PCORI.