My Mother 57 Years Old, Was Recently Diagnosed With CHF.

My mother 57 years old, was recently diagnosed with CHF. She was undergoing a cardiac mri but it had to be aborted after 11 minutes because her breathing was obstructed and her heart rate dropped. She was in ICU for a couple of days. Her condition has improved, she's taking a steroid and dieuretic because of water on her lungs. Her doctor wants to do another cardiac mri but she's afraid and refusing to do it. Is there any other way her heart can be checked out?