Since you didn t state what kind of arrhythmia was shown on your EKG, and the fact that your doctor didn t put you on an anticoagulant then hopefully it is not A-fib. But that doesn t mean what you were describing couldn t be this time. When someones heart over beats per minute the result can be that the blood doesn t completely empty from the heart chambers and thus makes like a whir-pool effect in the chamber. This aggravates the platelets ( the part of your blood that clots) causing small clots to form. When the heart goes back to normal rhythm, it is again an effective pump that pumps those clots out into the body. Then can be displaced to smaller blood vessels and logged there causing obstruction. This is how many heart attacks and strokes, DVT,and P.E s develop. What you are describing gives warrant for great concern. Go to the hospital since it is the weekend, and get it checked out. You only have one brain and one heart, when it is gone it is gone as you have seen by your family. They call it a golden hour for a reason, after an hour tissue death developes where ever the blood circulation is blocked. Stop smoking please, you already have enough risk factors without added ones that you can change like smoking and fatty foods. Some of the other answers here have described test pretty good so I won t go over that again. An echo cardiograhm will only show changes if there is heart muscle damage the effects the acutual pumping diffencancy or decreased blood flow to the the acutual heart muscle (with color flow). To little to late. Just can use meds to help try to regain better function at that point. edit: Once you have seen your doctor and he/she feels comfortable with it. Please ask for the medication Chantix to help you stop smoking. I know it is expensive but not as expensive as just a one time full work up per month and less than a pack a day habit at the prices of cigarettes. I have been on it. I am 25 year smoker and it is the only thing that has ever got me so close to saying I am a reformed smoker. Down to two a day, and that is just to help my digestive system ,so I don t become constipated. So If I go on my own I don t have one, and don t want one either. Best program ever in my personal opinion. Everyone sorry, it was me that thumbs down, on accident didn t relize till it hid your answers later, don t know how to fix it now. Ment to thumbs you up except the pot smoking one. So sorry!!!!!!!!!!!!!!!