I can see where you would be nervous so this should be investigated further. I would not only get an EKG but an echocardiogram (to make sure you have no structural heart disease, an EKG does not tell you this) and I probably would make this a stress echocardiogram where you walk/run on a treadmill while you are monitored to see if you are having an arrhythmia (abnormal heart rhythm) while you are exercising. A stress echocardiogram will allow us to look at the heart muscle, the heart valves, and while you exercise, we monitor your EKG to see if you develop any abnormal rhythms.
You should be evaluated by a Cardiologist before going back to exercise. Was your dad young when he developed his cardiomyopathy? Do you know what type he has?
Hope this helps. Good luck.
when I said MRI, I meant EKG