I think it’s similar to the fact that a good body weight can’t keep you from dying. However, controlling your body weight can help prolong your life and help control various medical conditions. Whatever propensity you have to have Afib, controlling various factors can help minimize the chances of having an attack. You’re more prone to Afib attacks if you drink heavily and gulp your booze down in a few swigs, if you’re dehydrated, if your potassium levels are low, if you’re very sleep-deprived, etc. My wife is a board-certified internist who, by her practice, is essentially a geriatrician. She said when I asked her just now that control of lifestyle factors can moderate the propensity of your heart to engage in episodes of atrial fibrillation. Just do an Internet search, for example, on whether alcoholics are more prone to suffer atrial fibrillation. That’s a lifestyle factor that damages your heart… I only drank in moderation (45 ml of 80-proof vodka a day), but both an RN practitioner and my cardiologist advised me to give up drinking, saying alcohol is a cardiac poison. So I did.
Edit_Update (from UCSF Medical Center): Alcohol Can Cause Immediate Risk of Atrial Fibrillation | UC San Francisco (ucsf.edu)