Is there a difference between signs/symptoms to terminating a cardiac exercise stress test and terminating exercise during cardiac rehab? It seems to me there is, at least w/regards the ST depression or elevation. For both, I have seen there needs to be >2mm AND >1mm. Which one is it? Even within the answer explanations in one test alone, it seems as though I see conflicting answers.

Yes, there are differences (even though they may appear similar) in the signs/symptoms for terminating a cardiac exercise stress test  and terminating exercise during cardiac rehabilitation. For one thing, stress tests are carried out to measure the heart’s ability to respond to external stress in a controlled clinical environment. Cardiac rehabilitation is prescribed for patients recovering from cardiac problems or lengthy hospital stays or admission and are usually administered in phases in which the exercises increase in intensity as the patient improves.

Most text books differ on the height of ST segment elevation or depression required for termination of cardiac rehabilitation. However, it is important to bear in mind that there are relative criteria (i.e. take precaution and observe the patient when they occur – but you don’t necessarily have to terminate the exercise) and absolute indicators (immediately terminate exercise when they are observed or when they occur). Also bear in mind that some form of ST elevation/depression is present in otherwise healthy members of the population. ST segment depression is the most common manifestation of exercise-induced myocardial ischemia [1]. Therefore a useful guide is termination of exercise with ST segment changes i.e depression or elevation > 2mm.

Reference 1, Reference 2, Reference 3, Reference 4