I would strongly recommend trying really hard to understand the physiology of the various congenital heart lesions, rather than just memorizing the differnent lesions.
For example, seperate the lesions by physiology (ductal dependent for pulmonary blood flow vs ductal dep for systemic blood flow vs ductal independant) rather than by how medical students learn them (left to right shunts vs R to L). Draw pictures, and simple pictures like box diagrams, to map out the flow of blood. By doing these things, you will really learn why they present like they do and be able to apply the lesions to their clinical presentations much easier.
Also, even thought there are a lot of cool things to focus on like congenital heart disease, fetal cards, electrophysiology, etc, dont forget about basic peds cardiology, which are common complaints the general pediatrician will deal with often....such as, murmurs, chest pain, syncope, palpitations, etc.
Good luck!
