I've never used MKSAP for Cardiology. Do you mean what books do fellow read for learning in general or studying for the board exam because it's completely different in a way. During fellowship, we read Grossman's for cath, Oh or Otto for echo, Braunwald for general cardiology questions. But I would say most of the learning is from fellow conferences, reading echos, ekgs, holters, caths, journal club, reading guidelines/journals, and the patient's themselves. Studying for boards, at least for me, was through a refresher, like the Mayo or ACC Board Review courses.