I had a cardiac MRI scan today and when they injected the adenosine if felt like I couldn t breathe and I felt faint with ringing in ears, and then felt freezing cold and trembling. I m 55 female wih recently diagnosed high blood pressure and left bundle branch block. I experienced tightness in my chest in April when at rest after a brisk walk on a very warm day.it lasted only a couple of minutes. Was the reaction today to do with an underlying problem or merely shock reaction to the adenosine?

Summarized question: Can experiencing faint ringing I ear, cold reaction to adenosine?