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Diseases and disorders of the heart are investigated by such techniques as cardiac catheterization. When this technique is used a thin tube or catheter is inserted through either a vein or artery. Then it is advanced to a major vessel and on into the heart. The entry area for this catheter is in most cases the arm or leg of the patient and a local anesthesia is given prior to the procedure which is always performed in a hospital.
The catheter, in many cases, will contain either a measuring instrument or other device at the tip. These types of catheters, depending on the device at the tip, are used in the heart for either diagnosis or treatment and will measure pressure, view the inside of blood vessels, narrow or widen a heart valve or clear a blocked artery without any major surgery. With pulmonary artery catheterization a catheter that is specially designed with a balloon at the tip is inserted into a vein in the neck or arm. It is then threaded through the right atrium and right ventricle in the heart to where the opening is for the pulmonary artery. It is then used to measure blood pressure in the heart chambers and major vessels. Even the amount of blood that heart puts out to the lungs can be measured using this procedure.
Once a cardiac catheter is in place doctors will often use it to draw samples of blood that is analyzed for oxygen and carbon dioxide content. Since, in most cases, the insertion of the catheter can cause abnormal heart rhythms, the heart is continuously monitored so the doctor can reposition the catheter to correct this problem. In cases where the abnormal rhythms remain, the catheter is completely removed. Some of the blood samples taken by a doctor through the catheter are used to do metabolic studies. Dyes are injected through the catheter that will show up on a movie type x-ray exposing the blood vessels and heart chambers. Any abnormal blood flow or anatomic abnormalities are seen and filmed while the x-rays are being taken. Samples of heart muscle tissue can be obtained from the catheter by passing instruments through the catheter to remove the tissue. These samples from inside the heart chamber are then used for microscopic examination or what is known as biopsy.
Cardiac catheterization creates an opportunity for doctors to measure the blood pressure in major blood vessels and the heart chamber separately at each site. This technique also makes it possible to sample the carbon dioxide and oxygen in different areas of the heart. By analyzing the motion of the left ventricle wall and calculating the ejection fraction a doctor can evaluate the pumping ability of the heart as well. This will tell the doctor how much injury has been done to the heart due to ischemic coronary artery disease or other diseases. As with any cardiac diagnostic procedure there are risk which increase with the severity of the disease and complexity of the procedure. With cardiac catheterization chances of a major complication such as stroke, heart attack or death in 1 in 1000.
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