I have recently been noticing that after intense excercise (over 90% of max. HR) I have a pounding heart rate and feel a little short of breath. This happens 1-2 hours after the exercise. I exercise often (6 days/week) and am an avid cyclist. I rode yesterday for 5 hours, including an hour long climb at a HR of 170BPM. 2 hours after I had completed my ride I noticed an uncomfortable pounding heart beat (it didn't seem overly fast) and a little short of breath. It lasted about an hour. I think I was well hydrated and used electrolyte sports drink (Gatorade) and water during the ride.
History: Am 43 years old, in good physical condition. Was treated for SVT (brought on only with intense exercise) with an ablation in January 2006. I take thyroid meds (Levoxyl 125mcg.) and levels have been recently tested. I also take Nasacort, Clarinex, Nexium.
Could there be a chemical or electrolyte inbalance causing these symptoms? I also have a lot of stomach discomfort (due to reflux) during long rides. Could this cause these heart symptoms?