have been trying to find (and failing) if the current recommendation is a screening ECG in everyone prior to initiating a TCA or just for those with a h/o cardiac dz? This is for a woman in her 50s.
I would order an EKG on any person given an TCA with history of cardiac disease.
With full acknowledgment that you perhaps tried this, and it didn't work...
I'd try to avoid the use of a TCA if possible. Antidepressants can be augmented with several agents such as lamictal, buspirone, an atypical, etc. I'd rather use that than a TCA on a person with a history of a cardiac disorder.
But if you are stuck, and want to consider a TCA, get the EKG. That's my recommendation. I don't know if you are going to find a specific text recommending this. As you likely know, several texts do not specify several things we do in medicine. For example, diabetes, few sources I've seen give the order of diet & excercise first, then try metformin, then glitazone, then insulin. The sources will mention what can be done, but not give a protocol, and protocol is often clinically taught, but not found in a book.
As a once new attending (hey I'm a fellow now), I recommend you be in a position where you can ask colleagues for support if you are stuck. That was one of the things I enjoyed about working in a hospital, and not private practice first thing out. This site can help.