I wouldn t worry about falling over dead. An EKG will show abnormalities such as Hypertrophic Obstructive Cardiomyopathy (HOCM) and would also show any arrhythmias that were present at the time. I m not sure what your cardiologist told you, but you may have had short bouts of atrial fibrilation (A Fib), or thrown a few random premature ventricular contractions (PVCs.) I am an echo tech myself (meaning that I conduct cardiac ultrasounds) and I can tell you from experience that if your doctor felt there was any need for an echo, he would not hesitate to order one. I m sure he saw something minor that was causing your symptoms, and felt no need to bring it up because he did not intend to treat it. Also, respiratory variation (changes in breathing) influences your heart rhythms and blood flow profiles. (Look up valsalva maneuver.) If your symptoms persist, I would ask your doctor for an echo simply for peace of mind. It would confirm or deny the presence of any valvular stenosis (blockage) or regurgitation (leaking), any VSD/ASD (hole in the walls between the lower or upper chambers of the heart), valvular prolapse/redundancy (long valve leaflets that snap open and shut), presence of tumors or clots, evidence of infarction, doppler velocities and volume measurements of bloodflow, and would rule out other visible physical defects. I also would tell your doctor that you may feel acute anxiety over this and he may prescribe some sort of anti-anxiety medication like alprazolam, or something. Good luck.