The time-poor candidate should read "A Practical Approach to Cardiac Anaesthesia" by Hensley Martin and Gravlee. Specifically, these two chapters are gold:
With the above, one should be able to scrape through.
Oh's Intensive Care Manual has several chapters which are relevant to this topic:
In spite of the pedigree, the author has not found this resource to be useful in his preparation. However, the time-rich candidate should read through these chapters at least once, to be familiar with the content of the infamous blue boxes. Additionally, it is difficult to find a single source on heart and lung transplantation which would be an improvement on the Macdonald and Jans chapter.
Summaries and discussions of cardiothoracic ICU topics from Life in the Fast Lane are made available as a list of links in the Resources section.