Angiography allows your doctor to measure the flow and pressure of the blood in the chambers of your heart and to see if the arteries that supply blood and oxygen to the heart muscle are blocked. During angiography, a dye is injected into your heart's chambers. Images are then captured using X-rays.

Cardiac catheterization is done first so that the dye can be injected through the catheter and into the heart. The movement of the dye through your heart and coronary arteries is recorded as an angiogram and viewed on a television monitor.

The arrow on the angiogram on the left shows where the flow of blood through an artery is being blocked. The angiogram on the right is the same artery after a stent has been inserted to open up the artery to improve blood flow.

Your doctors can put the catheter in different places, depending on which arteries or chambers of the heart they want to see. During dye injections, X-ray pictures are taken which can later be reviewed. You may notice a warm sensation throughout your body when the dye is injected. You may also be asked to cough vigorously. Let the doctor or nurse know if you have any chest discomfort. During the procedure, you will see monitors nearby and may be able to see your electrocardiogram electrocardiogram and the pictures of the heart and arteries. The total procedure may take one to two hours. However, getting ready and recovery will take an additional two to four hours.

Angiography is a safe test. The dye used is harmless. By drinking lots of liquids after the test, you can help rid your body of the dye. In rare cases, some people may have an allergic reaction to the dye. Tell your doctor before the test if you are allergic to iodine, shellfish or strawberries.

The For Patients section has instructions for preparing for cardiac catheterization, angiography and electrophysiology studies.