Cardiac catheterization involves risks and potential complications. Complications may become serious in some cases. Complications can occur during the procedure or recovery. Complications include: Abnormal heart rhythms (cardiac arrhythmias) Adverse reaction or problems related to sedation or contrast agents, such as an allergic reaction and problems with breathing Bleeding Blood clots that can cause a heart attack, stroke or death Damage to the artery from the catheter Exposure to radiation, which may be harmful in excessive doses. Your care team follows strict standards for X-ray techniques and will use the lowest amount of radiation possible to make the best images. Infection Kidney injury from the contrast agent, especially if you have kidney disease Low blood pressure Need for immediate open heart surgery Reducing your risk of complications You can reduce the risk of certain complications by following your treatment plan and: Following activity, dietary and lifestyle restrictions and recommendations before your procedure and during recovery Informing your doctor if you have kidney disease or diabetes Informing your doctor or radiologist if you are nursing or there is any possibility that you may be pregnant Notifying your doctor immediately of any concerns, such as bleeding, fever, or increase in pain Taking your medications exactly as directed Telling all members of your care team if you have any allergies, especially iodine or shellfish