Hi Gabriel

I stumbled on your post after more than three years doing research for the (exact) same issues you've described to the T!
In 2018 I suffered a pulmonary embolism that nearly took my life, and the root cause was attributed to a genetic blood clotting anomaly calmed Factor VIII. I later rebounded from this catastrophic even and within 8 months, I was back at the same athletic performance prior the PE, although I'll be taking blood thinners for the rest of my life as the factor VIII is a permanent condition. Please note that I've omitted to mention that I exercised and still do, 5 to 6 days per week and am in relatively excellent health otherwise. Back to the main issue, 12 months after the PE, I suffered a sudden onset of arterial fibrillation, for no apparent reason I was sitting at my desk at the office and my heart rate went from +/-45bpm to +/-130, started feeling faint, unwell, sweating, I was headed out of office for a meeting, but that never happened as my girlfriend called an ambulance and I was transported urgently at the hospital. There I was quickly checked by the ER personnel, immediately referred to a cardiologist specialising in electrophysiology of the heart, and recommended a transcatheter ablation. I quickly have consent and the intervention was done the morning after, completely restauring regular heart rhythm. Sadly, after taking note of my health history and lifestyle, the cardiologist attributed the sudden Afib to a constant over exertion of the heart, by constant intense training, apparently there's a link between excessive exercise workloads and sudden out progressive onset of Afib. Now, having said that, a month or so later I started to develop and I quote, (the exact same symptoms) you've described. At first the cardiologist suggested that there was a remote possibility that when they did the ablation using RF(radiofrequency), they may have caused some intra esophageal damage that may be causing the symptoms, needled to say I was alarmed that I would have to deal with this for the rest of my life. However, I was trying through a battery of tests, pulmonary function tests, stress test ECGs, transesophageal echocardiogram, asthma test, CO2 tests, basically the lot of available tests out there, and all turned out normal. I was followed for 3 years following the ablation and was referred to the same tests 12 months after the initial tests, also referred to a pneumologist and did methacholine test and some other pulmonary function tests and nothing, I was declared to be in perfect health. However, the pulmonologist did mention that he had one other case in the past that displayed the same symptoms we both had and it was attributed to a form of anxiety attributed to a traumatic experience, a form of PTSD if you'd like. I reject this assessment at the time, because I was never an anxious individual, I managed stress extremely well, the sports definitely gave me calm and good sleep, so I brushed it aside. The issues you described however, never ceased. Slowly over time, it was talking a psychological toll. In the past six months, I have been doing similar breathing exercises as you described, in order to retain my breathing, using the 4-4-4-4 method, breath in though nose for 4 seconds, hold breath for 4 seconds, exhale through mouth for 4 seconds, again hold for 4 seconds and repeat. Over time this has had some meaningful impact, not 100% but better move the less. I was recommended some antidepressants which I refused to take. I'm not fully convinced that this is an anxiety issue and a part of me still believes it's a physiological issue. I'm constantly doing research on this issue and won't give up. Any little improvement is an added bonus and any post similar to yours, tells me in not alone dealing with this, is a form of relief of sort.
So Gabriel, of there's anything else you come across that has improved your status, or if there's anyone else that lives with these similar issues, please post. Even if you think it's of no significance, as a community we may stumble upon something of importance that could lead to some answer and added well-being.

Thanks a bunch
Roberto