I am a physician, board-certified in internal medicine (1979), emergency medicine (1991) and medical toxicology (1994), who has significant experience in public health and clinical infectious diseases.  This report is very delayed because a previous attempt to report to VAERS was aborted by frustration with the reporting system.  I am attempting to report an adverse event a second time, because I believe, but cannot prove, that I had a serious cardiac event caused by the Moderna COVID-19 vaccine. Prior to immunization, I had never experienced any arrhythmia except for occasional ectopic beats, and specifically have never had atrial fibrillation or flutter, nor ventricular tachycardia.  A cardiologist follows me for hypertension, hypercholesterolemia, a remote history of TIAs and very mild congestive heart failure.  He has performed a number of stress tests and never found evidence of CAD.  Echocardiogram is normal.  I can remember at least 3 simple fainting episodes during childhood, all of which occurred while sitting in a church or auditorium, and am familiar with vasovagal syncope. Moderna COVID 19 vaccine was administered to me on 1-13-21 and 2-10-21.  These vaccinations were the most difficult of my life, resulting the next day in fever, myalgia, intense malaise, headache and fatigue, followed by quick recovery the following day.  In the months which followed, I felt some episodes of brief palpitations, but felt otherwise well. Then in May 2021 I experienced an episode of frank syncope which was quite frightening.  During normal activity in a standing position, I had the very sudden perception that something was very wrong, sat down on a couch, and lost consciousness.  The next thing I remember was feeling like I was floating through dark space, with intense pain all over.  Distinctly, I remember thinking, so this is what it is like to die.  Very slowly my vision returned, and I realized that I was alive, extremely diaphoretic and pale.  When the episode begin, I was with my 3 year old grandson in our basement.  On awakening I was alone.  Eventually, I was able to crawl up the stairs, where my wife called me and dialed EMS.  She estimated that our grandson had come upstairs by himself about 10-15 minutes previously, so I was out at least that long. Subsequent cardiac monitoring revealed rapid atrial fibrillation and flutter, both of which were new diagnoses.  I was placed on apixaban and carvedilol.  In June I began keeping track of my heart rhythm with a smart watch.  I experienced multiple but brief episode of rapid atrial fibrillation.  Then, in August, all arrhythmias ceased.  None in September and October.  Then I received a Moderna booster on 10-25-21.  Multiple but brief episode of rapid atrial fibrillation again occurred in November and December, then ceased.  I have detected no arrhythmias at all in 2022. I am well aware that association is not causation, but also aware that myocarditis has been associated with mRNA vaccine in younger men.  Given the temporal association of my two periods of atrial fibrillation occurring after vaccination then ceasing with time, I believe that the Moderna vaccine must be highly suspected as the cause.