I would get a second opinion, and treat the problem of stress. Rather than an evasive cath, a ct angiogram is a better option if you want peace of mind and a reference for any future tests.
I have no pain with exertion, have not been put on any meds as of yet, the only time I have ever had any pain is when I feel stressed (I have 2 teenagers) :) this procedure is scheduled for this coming Monday and I am having second thoughts about going ahead with the cath, do you think I should get a second opinion and the funny thing i'm a nurse!!! but i've only worked ob/gyn for the last 15years so i'm not familiar with all the aspects of the heart.
ST depression is an often an indication of partial occlusion of a coronary artery but not conclusive. If you are going for heart cath, be prepared to accept a stent included with the test (more money). AHA/AAC guidelines recommend a stent implant if the occlusion is greater than 70%. There are cardiologists that stent occlusions less than 70%!!
Family history is considered a risk, but to go for a cath based on that risk only is usually not a consideration and doesn't follow the AHA/AAC guidelines. If you have angina with exertion, does medication provide relief? If it does provide relief, that indicates your arteries are dilated with mediation and a decision for a cath should take that into consideration.