Why must nitroglycerin be discontinued in a patient who is about to undergo stress testing?

Answer 1

Multiple causes are there:
1) nitrates cause vasodilatation, and can result in fall of BP, and it increases heart rate, and can result in life threatening complications of acute nature .
2)since the objective is to assess maximum target heart rate attainable under normal condition, it may interfere with the test and a FALSE RESULT can be achieved.
3)even prior to anesthesia, all cardiac medications are stopped.
Hope you have got an insight view.

Answer 2

Orthostatic hypotension.....the feeling of getting up too fast, you become lightheaded and faint. Nitrides (nitroglycerin) causes arteries and veins to open causing blood to rush everywhere except your brain, your blood pressure drops and you faint....not a pretty picture.

Answer 3

Because they want to measure the full stress on the heart w/o drugs.Its an evaluation to see how much stress the heart can take.