NTG Administration during SPECT Resting Myocardial Flow Test

During recent hospitalization for R/O Anterior Septal MI I was given SPECT Resting Myocardial Flow Test in Nurclear Medicine.
I had been on NTG paste 1 inch 30 hrs prior to and during SPECT evaluation. How would concomitant NTG administration during SPECT evaluation affect outcome? Thankyou, Kamalamalama

[Cleveland Clinic]

Kamalamalama,

Nitroglycerine can dilate the coronary arteries.  A stress test compares resting images of coronary blood flow to the images taken under stress conditions.  

If your arteries are dilated at rest, then theoretically if the difference in perfusion may be slightly attenuated. If you are not on nitroglycerine as a standing medicine this could potentially interfere with the applicability of the test when you are off.

However, you body does become tolerant to nitoglycerine over several hours. This is people that routinely take nitroglycerine (via patches etc..) are told to take the patch off for several hours a day.  If you were on  the paste for 30 straight hours, it probably really had no effect on the images.

good luck