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Cardiac catheterization (heart cath) is the insertion of a catheter into a chamber or vessel of the heart. This is done for both diagnostic and interventional purposes. Diagnostic, simply put is looking to see if everything is okay, whereas interventional means ;that something needs to be fixed with a balloon or stent. During this procedure the physician can obtain information regarding the coronary arteries and the various chambers of the heart, including the heart valves.
Coronary catheterization
[edit]Procedure
[edit]Local anaesthetic is injected into the skin around the nerve, usually in the right groin, to numb the area. In some centers, access to the coronary arteries is made via the right radial or brachial artery (wrist or arm respectively). However, the majority of cases are still performed via the right groin. A puncture is then made with a needle in either the femoral artery in the groin or the radial artery in the wrist, (Seldinger technique), before a guidewire is inserted into the arterial puncture. A plastic sheath (with a stiffer plastic introducer inside it) is then threaded over the wire and advanced into the artery. The wire is then removed and the side-port of the sheath is aspirated to ensure the sheath is patent. It is then flushed with heparinized saline. This arterial sheath, acts as a conduit into the artery for the duration of the procedure.
Catheters are inserted using a guidewire and gently guided towards the heart. Once in position above the aortic valve the guidewire is then removed. The catheter is then engaged into the origin of the coronary artery (either left main stem or right coronary artery) and x-ray opaque, iodine-based contrast is injected in order to visualize the coronary vessels via x-ray fluoroscopy.
After the physician has taken several images of the coronary artery from different angles,the catheter is removed. At the end of the procedure the sheath is removed and firm pressure is applied to the site to prevent bleeding. This may be done by hand, known as manual pressure, or with a mechanical device. Other closure techniques include an internal suture, a plug, or a sealant type device. If the femoral artery was used, the patient will probably be asked to lie flat with the affected extremity straight (ie. the right leg)for several hours to prevent bleeding or the development of a hematoma. If the arm is used, the patient can ambulate sooner. Cardiac interventions such as the insertion of a stent prolong both the procedure itself as well as the post-catheterization time spent in allowing the wound to heal.
A cardiac catheterization is a general term for a group of procedures that are performed using this method, such as coronary angiography, as well as left ventricle angiography. Once the catheter is in place, it can be used to perform a number of procedures including diagnostic angiography,angioplasty, PCI (percutaneous coronary intervention), thrombectomy, balloon septostomy, and/or an Electrophysiology study.
Indications for investigational use
[edit]This technique has several goals:
- confirm the presence of a blockage, clot, or other heart disease
- quantify the severity of the disease and its effect on the heart
- seek out the cause of a symptom such as shortness of breath or signs of cardiac insufficiency
- make a patient assessment prior to heart surgery
- to clear a patient to have other surgical procedures
Investigative techniques used with coronary catheterization
[edit]- to measure intracardiac and intravascular blood pressures
- to take tissue samples for biopsy
- to inject various agents for measuring blood flow and oxygen levels in the heart; also to detect and quantify the presence of an intracardiac shunt
- to inject contrast agents in order to study the shape of the heart vessels and chambers and how they change as the heart beats
Catheterization of chambers and valves
[edit]Catheterization of cardiac chambers and valves may be performed during this catheterization procedure, and may also involve nearby vessels that supply the chest and arms, and major vessels such as the aorta. A pigtail catheter is utilized for cardiac ventriculography of the left ventricle. Radionuclide ventriculography is an older method whose use has largely been replaced by whose use has largely been replaced by echocardiography).
The catheter along with a hemodynamic monitor has the ability to measure the pressure gradient across a valve and derive a valve area from it. Thereby, it can assist in diagnosis of, for example, aortic stenosis.[1]
This is also the procedure used in balloon septostomy, which is the widening of a foramen ovale, patent foramen ovale (PFO), or atrial septal defect (ASD) using a balloon catheter.
History
[edit]The history of cardiac catheterization dates back to Claude Bernard (1813-1878), who used it on animal models. Clinical application of cardiac catheterization begins with Werner Forssmann in the 1930s, who inserted a catheter into the vein of his own forearm, guided it fluoroscopically into his right atrium, and took an X-ray picture of it. Forssmann won the Nobel Prize in Physiology or Medicine for this achievement, though hospital administrators removed him from his position owing to his unorthodox methods. During World War II, André Frédéric Cournand, a professor at Columbia University College of Physicians and Surgeons who also shared the Nobel Prize, and his colleagues developed techniques for left and right heart catheterization.
References
[edit]- ^ Elizabeth D Agabegi; Agabegi, Steven S. (2008). Step-Up to Medicine (Step-Up Series). Hagerstwon, MD: Lippincott Williams & Wilkins. ISBN 0-7817-7153-6.
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External links
[edit]- MedlinePlus Medical Encyclopedia: Cardiac catheterization
- eMedicine: Cardiac Catheterization (Left Heart)
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Category:Medical tests