This is not an answer to your question but I will tell you that people who have had cardiac issues and cardiac surgeries are documented to have anxiety and depression after surgery or event. It is only by dealing with it straight up and identifying it as a physiological reaction to a condition that it can then be dealt with. You may make an appointment with a cardiologist she likes and talk to him about what you are seeing, what you suspect, and what I have said here. Many people need antidepressants for a time to help them through that period and it must be more difficult if it is not identified. There is also a bit of research that I have seen that documents even general anesthsia being related to post surgery depression. Not to mention the emotional stress of such an experience. Hope this helps.