Thank you David for your comments. Yes I agree with you upon research but have had HOCM for around 15 yrs and pretty much symptom free (lately a few) but have never had Atrial fibrillation until I started Mavacamten (also a known side effect). I have had A F for around a month now and stopped Mavacamten about a month ago AF has stopped. Can only assume it’s the drug disappointingly. Very happy for those that have had their lives turned around. Regards