Heme-Onc,
I did research as a first year in the Cariac EP division, so take what I say for what it is, the experiences gleaned from two summer months as a first year medical student. The EP fellows whom I did research with worked long hours (came in btw 6 - 6:30, finished anywhere from 4 - 8 pm) but the work was extremely interesting and rewarding (EP studies, AICD/Pacemaker implantation, clinic - which largely consisted of checking out the cool toys you put in). As far as I understood, getting an EP fellowship after cardiology was not very difficult (the hard part was getting the cards fellowship in the first place). At my hospital, the EP fellowship is 1.5 years. Most of the fellows I worked with were foreign grads, although they were some of the best I have ever interacted with. The pay is excellent, even from a cardiology perspective - lots and lots of billable procedures (even the reprogramming of a pacemaker, which can take 5 minutes, pays!). But it is extremely challenging and requires alot of dedication. It's definitely NOT a lifestyle field. After my two months there, I think I pretty much realized I wanted more time with my friends and family, but if u have the stamina, go for it. Also, if u have a research bent, there is ALOT going on in the field.
