my "irregular" heart beat take II

i just got off the phone with a UH physician who suggested last week that I get an EKG (heart ultrasound) in order to gain more insight into what could possibly be causing my abnormal symptoms. well, she shared with me my results and the test showed that nothing is wrong with the valves or overall activity of my heart, but i have been informed that it would be wise to sit out of tomorrow's 10-mile relay race (i think i am still going to jog/walk it). i also must monitor my heart for a 24-hour, high-intensity period sometime soon. good grief!