It is not surgery. Long, flexible tubes called catheters, are used to both take measurements and to inject dye into your blood vessels and into your heart. Cardiac catheterization is also performed to evaluate heart valve disease and congenital heart abnormalities.
Cardiac catheterization is performed for a variety of reasons.
You may have been taking nitroglycerin to relieve your angina, and recently your doctor has had to increase the dosage. Ventriculograms enable your doctor to visualize your left ventricle from many angles. They reveal much information about the ventricle's structure and functioning. You might have already taken other less invasive diagnostic tests such a treadmill test, an echocardiogram or a nuclear scan. Based upon the results of those tests, your history, physical examination, and symptoms, your doctor has determined that additional information is required.