Hi Troubled Heart,
A cardiologist is a physician who is certified to treat problems of the cardiovascular system (i.e. heart, arteries, and veins).
An electrocardiologist is a cardiologist specializing in heart rhythms, such as a too slow/fast heart rates and EKG results which is influence by the electrical signals of the heart.
All the best,
Lisa Nelson RD
Be Heart Healthy and Lose Weight