Hi. Thank you for your question and welcome to HCM. I carefully read your query. I can see that, basically, almost every cardiac check-up test was done and they revealed a normal heart function and structure. So, I am safe and confident to say that this problem does not have a heart origin. The symptoms you are describing - fast heart rate and terrible feeling of anxiety - are more symptoms of generalized anxiety disorder with panic attacks. The feeling of I am going to die or What is wrong with me? trigger a panic attack with a flush of adrenalin in the system, which trigger increased heart rate and blood pressure. Therefore, my recommendation is that you consult a clinical psychologist or a psychiatrist to treat the anxiety with benzodiazepines and/or drugs from other classes, if mood swings and declined of quality of life and work are also present. As for the heartburn, it can come from a chronic gastritis (chronic inflammation of the stomach s innermost lining). Some certain food should be avoided, because they keep this inflammation alive : chocolate, caffeine, spicy food, pickles, grilled food, tobacco, alcohol. Also, psychological stress keep the ongoing inflammation. I would also recommend a 4-week course with protein pump inhibitors (PPI). Consult your general practitioner about the frequency of taking and the dosage of these drugs. I hope I have been of help. Wish you a good health. Kind regards, Dr. Meriton