First off, let me confess, I LOVE congenital heart disease. If you search my previous posts, I have posted on peds cards numerous times in the past. recently, I decided to pass on becoming a cardiologist in exchange for being an intensivist.
My primary reason is that I went from rotation to rotation, I liked everything, especially heme-onc and renal. Although I love congential heart disease/heart failure/heart transplant/cardiomyopathy, I hate electrophysiology, I started to realize that I hated EP, I never want to cath all day, I don't want to sit in a dark room and read echos nor stand at the bedside of a pt to perform one. So I realized that in PICU, I would still be exposed to congential heart disease/heart failure/heart transplant/cardiomyopathy without having to do all the other stuff and still being able to be exposed to other areas of peds that I enjoy as well. If I end up loving the cardiac areas of PICU fellowship so much, I can always then either do an extra year in cardiac critical care or try to combine a cards/picu fellowship.
Other reasons I find PICU more desireable is the lack of clinic and lack of intense long-term relationships with patients, which for others may be a huge disadvantage. I also love how you never bring your work home with you as a PICU doctor...once u leave the hospital, you have a colleague to take over. At our institution, there are 13 PICU faculty members and each does service anywhere from 4-24 weeks a year among the PICU, CICU, sedation service, and burn unit. The rest of the time is spent doing various activities, such as research, administration, teaching, etc. I like having so much time to pursue other activities outside of clinical service, which is less likely to be afforded to a cardiologist.
In terms of research, I think there is a lot of basic science in either. It is of course institution dependent. What I like about PICU is that almost any area of basic science can be applicable to your career on some level. Our fellowship program allows PICU fellows to do research with intensivists, cardiologists, hematologists, oncologists, etc.
In terms of competitiveness, cards is quickly becoming crazy competitive. PICU remains among the least competitive pediatric fellowships to obtain, as there are more spots than applicants each year, and great programs go unfilled year after year. Such a situation creates a high demand for intensivists, which makes the job market favorable.
I think to make this decision, you have to answer a few "simple" questions.
(1) Do you want to know everything about a single organ, or a lot about every organ?
(2) Do you want to see patients as an outpatient?
(3) Do you want to have long-term continuity of care?
If you can answer these, it will likely help narrow the choice down a bit.