Alright, this is really beginning to frustrate me. For roughly 10 years since I was 7 years old, I've been experiencing problems with abnormally high heart rates originating from exercise and/or stressful situations. Doctors simply assumed that it wasn't serious. But, about 3 months ago I was sitting in my room doing some homework when out of nowhere I felt a sudden indescribable sensation in my chest, followed by a rapid increase in my heart rate. It increased to about 160 bpm, and my parents called 911. Once at the hospital I was injected with adenosine (extremely unpleasant by the way), which only worsened the situation. Eventually, I was injected with toprol XL, which over the next 20 minutes decreased my heart rate to approximately 100 bpm. I was sent home within the next few hours, and prescribed daily tablets of toprol XL. Well, I took these beta blockers over the next week or so, but due to some chest pains and extreme fatigue I was taken off of them. Over the next few weeks I felt alright until once again another episode struck, and I was hospitalized again. Toprol XL solved the problem, but due to past issues I once again didn't take it on a daily basis. I soon scheduled a visit with a cardiologist who noted that my PR interval was short. My cardiologist suggested the possibility that I may have LGL syndrome (a subset of Wolff-Parkinson-White Syndrome). So, I was scheduled for a catheter ablation the next week. Well, I had the surgery, but no accessory pathway was found, so the problem is not LGL syndrome nor WPW.
At this point, the cardiologist is stumped. I've done blood, urine, and other tests, but I still have no idea as to what the problem is. It's strange because my tachycardia is triggered by stress and exercise, but it also happens at random. So, it can't simply be caused solely by stress or exertion, due to the randomness of it.
Extra information: My blood pressure is about 114/70 when rested. But, when I become stressed, it can increase to 134/93. Also, my random episodes of tachycardia are classified as supraventricular.
Thank you for reading, and I hope that someone may have an idea.