Many here will know of the late Prof Phillippe Coumel and his contributions to understanding the autonomic influences on AF, describing one such as vagally-mediated. But you may also be aware that many in cardiology are either unaware of his work, or do not use it clinically.
I was encouraged to find via Linkedin that a Belgian team is continuing to look at this. The paper is "Autonomic Nervous System Activity before Atrial Fibrillation Onset as Assessed by Heart Rate Variability" with author Jean-Marie Grégoire et al. Published 8th Jan 2025. A Linkedin conversation indicated that Grégoire had met Coumel and was very familiar with his work and that they were standing on the shoulders of this great cardiologist.
Another Linkedin post from a team of researchers was offering a database (presumably anonymised) of Holter traces showing the onset of AF episodes, so that people working in this area, particularly those using AI/Machine Learning can train their models to enable clinical usage of these aspects.
In 30 years of my AF, no cardiologist has ever looked at my HRV to help characterise what I know from my own observations is often vagally-mediated onset to my AF. Let's hope progress will be made towards practical clinical application before too long.