cardiac catheterization

Cardiac Catheterization

Definition

Cardiac catheterization (also called heart catheterization) is a diagnostic procedure which does a comprehensive examination of how the heart and its blood vessels function. One or more catheters is inserted through a peripheral blood vessel in the arm (antecubital artery or vein) or leg (femoral artery or vein) with x-ray guidance. This procedure gathers information such as adequacy of blood supply through the coronary arteries, blood pressures, blood flow throughout chambers of the heart, collection of blood samples, and x rays of the heart's ventricles or arteries.A test that can be performed on either side of the heart, cardiac catheterization checks for different functions in both the left and right sides. When testing the heart's right side, tricuspid and pulmonary valve function are evaluated, in addition to measuring pressures of and collecting blood samples from the right atrium, ventricle, and pulmonary artery. Left-sided heart catheterization is performed by way of a catheter through an artery which tests the blood flow of the coronary arteries, function of the mitral and aortic valves, and left ventricle.

Purpose

The primary reason for conducting a cardiac catheterization is to diagnose and manage persons known or suspected to have heart disease, a frequently fatal condition that leads to 1.5 million heart attacks annually in the United States.Symptoms and diagnoses that may lead to performing this procedure include:

chest pain, characterized by prolonged heavy pressure or a squeezing pain
abnormal treadmill stress test
myocardial infarction, also known as a heart attack
congenital heart defects, or heart problems that originated from birth
a diagnosis of valvular-heart disease
a need to measure the heart muscle's ability to pump blood

Typically performed along with angiography, a technique of injecting a dye into the vascular system to outline the heart and blood vessels, a catheterization can aid in the visualization of any blockages, narrowing, or abnormalities in the coronary arteries. If these signs are visible, the cardiologist may assess the patient's need and readiness for coronary bypass surgery, or perhaps a less invasive approach, such as dilation of a narrowed blood vessel either surgically or with the use of a balloon (angioplasty).When looking at the left side of the heart, fluoroscopic guidance also allows the following diagnoses to be assessed:

enlargement of the left ventricle
ventricular aneurysms (abnormal dilation of a blood vessel)
narrowing of the aortic valve
insufficiency of the aortic or mitral valve
the detour of blood from one side of the heart to the other due to septal defects (also known as shunting)

Precautions

Cardiac catheterization is categorized as an "invasive" procedure which involves the heart, its valves, and coronary arteries, in addition to a large artery in the arm or leg. Due to the nature of the test, it is important to evaluate for the following conditions before considering this procedure:

A diagnosis of a bleeding disorder, poor kidney function, or debilitation. Any of these pre-existing conditions typically raises the risk of the catheterization procedure and may be reason to cancel the procedure.
A diagnosis of heart valve disease. If this is detected, antibiotics may be given before the test to prevent inflammation of the membrane which lines the heart (endocarditis).

Description

To understand how a cardiac catheterization is able to diagnose and manage heart disease, the basic workings of the heart muscle must also be understood. Just as the body relies on a constant supply of blood to aid in its everyday functions, so does the heart. The heart is made up of an intricate web of blood vessels (coronary arteries) that ensure an adequate supply of blood rich in oxygen and nutrients. It is easy to see how an abnormality in any of these arteries can be detrimental to the heart's function. These abnormalities cause the heart's blood flow to decrease and result in the condition known as coronary artery disease or coronary insufficiency.Catheterization is a valuable tool in detecting and treating abnormalities of the heart. Through the use of fluoroscopic (x ray) guidance, a catheter, which may resemble a balloon-tipped tube, is strung through the veins or arteries into the heart, so the cardiologist can monitor a body's various functions at each moment.Generally a test that lasts two to three hours, a patient should expect the following prior to and during the catheterization procedure:

A mild sedative may be given that will allow the patient to relax but remain conscious during the test.
An intravenous needle will be inserted in the arm to administer medication. Electrodes will be attached to the chest to enable the painless procedure known as an electrocardiograph.
Prior to inserting a catheter into an artery or vein in the arm or leg, the incision site will be made numb by injecting a local anesthetic. When the anesthetic is injected it may feel like a pin-prick followed by a quick stinging sensation. Pressure may also be experienced as the catheter travels through the blood vessel.
After the catheter is guided into the coronary-artery system, a dye (also called a radiocontrast material) is injected to aid in the identification of any abnormalities of the heart. During this time, the patient may experience a hot, flushed feeling or a quickly passing nausea. Coughing or breathing deeply aids in any discomfort.
Medication may be given during the procedure if chest pain is experienced, and nitroglycerin may also be administered to allow expansion of the heart's blood vessels.
When the test is complete, the physician will remove the catheter and close the skin with several sutures or tape.

Preparation

Prior to the cardiac catheterization procedure, it is important to relay information to the physician or nurse regarding allergies to shellfish (such as shrimp or scallops) which contain iodine, iodine itself, or the dyes that are commonly used in other diagnostic tests.Because this procedure is categorized as a surgery, the patient will be instructed not to eat or drink anything for at least six hours prior to the test. Just before the test begins, the patient will urinate and change into a hospital gown, then lie flat on a padded table that may also be tilted in order for the heart to be examined from a variety of angles.

Aftercare

While cardiac catheterization may be performed on an out-patient basis, a patient may require close monitoring following the procedure while remaining in the hospital for at least 24 hours. The patient will be instructed to rest in bed for at least eight hours immediately after the test. If the catheter was inserted into a vein or artery in the leg or groin area, the leg will be kept extended for four to six hours. If a vein or artery in the arm was used to insert the catheter, the arm will need to remain extended for a minimum of three hours.The patient should expect a hard ridge to form over the incision site that diminishes as the site heals. Bluish discoloration under the skin at the point of insertion should also be expected but fades in two weeks. It is also not uncommon for the incision site to bleed during the first 24 hours following surgery. If this should happen, the patient should apply pressure to the site with a clean tissue or cloth for 10-15 minutes.

Aftercare (Illustration by Argosy Inc.)

Risks

Similar to all surgical procedures, the cardiac catheterization test does involve some risks. Complications that may occur during the procedure include

cardiac arrhythmias (an irregular heart beat)
pericardial tamponade (a condition that causes excess pressure in the pericardium which affects the heart due to accumulation of excess fluid)
the rare occurrence of myocardial infarction (heart attack) or stroke may also develop due to clotting or plaque rupture of one or more of the coronary or brain arteries.

Before left-side catheterization is performed, the anticoagulant medication heparin may be administered. This drug helps decrease the risk of the development of a blood clot in an artery (thrombosis) and blood clots traveling throughout the body (embolization).The risks of the catheterization procedure increase in patients over the age of 60, those who have severe heart failure, or persons with serious valvular heart disease.

Normal results

Normal findings from a cardiac catheterization will indicate no abnormalities of heart chamber size or configuration, wall motion or thickness, the direction of blood flow, or motion of the valves. Smooth and regular outlines on the x ray indicate normal coronary arteries.An essential part of the catheterization is measuring intracardiac pressures, or the pressure in the heart's chambers and vessels. Pressure readings that are higher than normal are significant for a patient's overall diagnosis. The pressure readings that are lower, other than those which are produced as a result of shock, typically are not significant.An ejection fraction, or a comparison of how much blood is ejected from the heart's left ventricle during its contraction phase with a measurement of blood remaining at the end of the left ventricle's relaxation phase, is also determined by performing a catheterization. The cardiologist will look for a normal ejection fraction reading of 60-70%.

Abnormal results

Cardiac catheterization provides valuable still and motion x-ray pictures of the coronary arteries that help in diagnosing coronary artery disease, poor heart function, disease of the heart valves, and septal defects (a defect in the septum, the wall that separates two heart chambers).The most prominent sign of coronary artery disease is the narrowing or blockage in the coronary arteries, with narrowing that is greater than 70% considered significant. A clear indication for intervention (by angioplasty or surgery) is a finding of significant narrowing of the left main coronary artery and/or blockage or severe narrowing in the high, left anterior descending coronary artery.A finding of impaired wall motion is an additional indicator of coronary artery disease, aneurysm, an enlarged heart, or a congenital heart problem. Using the findings from an ejection fraction test which measures wall motion, cardiologists look at an ejection fraction reading under 35% as increasing the risk of complications while also decreasing a successful long term or short term outcome with surgery.Detecting the difference in pressure above and below the heart valve can verify heart valve disease. The greater narrowing correlates with the higher pressure difference.To confirm septal defects, a catheterization measures oxygen content on both the left and right sides of the heart. The right heart pumps unoxygenated blood to the lungs, and the left heart pumps blood that contains oxygen from the lungs to the rest of the body. Right side elevated oxygen levels indicate left-to-right atrial or ventricular shunt. A left side that experiences decreased oxygen indicates a right-to-left shunt.

Resources

Organizations

American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org.National Heart, Lung and Blood Institute. P.O. Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. http://www.nhlbi.nih.gov.

Key terms

Aneurysm — An abnormal dilatation of a blood vessel, usually an artery. It can be caused by a congenital defect or weakness in the vessel's wall.Angiography — In cardiac catheterization, a picture of the heart and coronary arteries is seen after injecting a radiopaque substance (often referred to as a dye) throughout the veins and arteries.Angioplasty — An alternative to vascular surgery, a balloon catheter is used to mechanically dilate the affected area of the artery and enlarge the constricted or narrowed segment.Aortic valve — The valve between the heart's left ventricle and ascending aorta that prevents regurgitation of blood back into the left ventricle.Catheter — A tube made of elastic, elastic web, rubber, glass, metal, or plastic used to evacuate or inject fluids into the body. In cardiac catheterization, a long, fine catheter is used for passage through a blood vessel into the chambers of the heart.Coronary bypass surgery — A surgical procedure which places a shunt to allow blood to travel from the aorta to a branch of the coronary artery at a point past an obstruction.Left anterior descending coronary artery (LAD) — One of the heart's coronary artery branches from the left main coronary artery which supplies blood to the left ventricle.Mitral valve — The bicuspid valve which is between the left atrium and left ventricle of the heart.Pulmonary valve — The heart valve which is positioned between the right ventricle and the opening into the pulmonary artery.Shunt — A passageway (or an artificially created passageway) that diverts blood flow from one main route to another.Tricuspid valve — The right atrioventricular valve of the heart.

cardiac

[kahr´de-ak] 1. pertaining to the heart" >heart.2. pertaining to the ostium cardiacum" >ostium cardiacum.cardiac arrest sudden and often unexpected stoppage of effective heart action. Either the periodic impulses that trigger the coordinated heart muscle contractions cease or fibrillation" >ventricular fibrillation or flutter occurs in which the individual muscle fibers have a rapid irregular twitching. The majority of victims of cardiac arrest suffer from ventricular fibrillation, and most have severe coronary artery disease. The only chance for survival for many who have unexpected cardiac arrest is successful implementation of emergency cardiac care and cardiopulmonary resuscitation (CPR). Reduction of the incidence of cardiac arrest and sudden death is a major concern of the American Heart Association and the American Red Cross.
Programs aimed at achieving the goal of reduced mortality from cardiac arrest include education of the general public in ways to avoid the development of coronary artery disease in the first place, and secondarily, training lay people and health care professionals and paraprofessionals in the techniques of CPR and emergency cardiac care.
Although cardiac arrest usually is related to preexisting coronary artery disease, there are other events in which the prompt delivery of CPR alone could mean survival for the victim. These include the cessation of heart and lung action as a result of drowning, suffocation, electrocution, drug overdose, and severe accidental trauma.cardiac catheterization the insertion of a catheter into a vein or artery and guiding of it into the interior of the heart for purposes of measuring cardiac output, determining the oxygen content of blood in the heart chambers, and evaluating the structural components of the heart. It is indicated whenever it is necessary to establish a precise and definite diagnosis in order to determine whether heart surgery is necessary and to plan the surgical approach.

A, Right-sided heart catheterization. The catheter is inserted into the femoral vein and advanced through the inferior vena cava (or, if into an antecubital or basilic vein, through the superior vena cava), right atrium, and right ventricle and into the pulmonary artery. B, Left-sided heart catheterization. The catheter is inserted into the femoral artery or the antecubital artery. The catheter is passed through the ascending aorta, through the aortic valve, and into the left ventricle. From Ignatavicius and Workman, 2002.Patient Care. Patients scheduled for cardiac catheterization experience a high level of stress. They are fearful and anxious because the procedure involves the heart, has a potential for some rather serious complications, and could indicate a need for cardiac surgery. Prior to the catheterization the patient will need to know that it is not a surgical procedure, even though a consent form must be signed, food and fluids are restricted, and a surgical preparation of the catheter insertion site is done. The patient should be told of these and other preparations as well as the physical features of the laboratory in which the catheterization is to be done.
During the initial assessment it is important to find out whether the patient has any allergies. The contrast medium used contains iodide salts; if a patient is allergic to iodine or seafood, a contrast medium that does not contain iodine must be used, or antihistamines must be administered before the procedure. A mild tranquilizer or hypnotic may be given just before the procedure to help the patient relax, but a general anesthetic is not used. Patients need to know that they must be awake and cooperative during the procedure. They will be asked to stay in a certain position, cough, breathe deeply, and possibly exercise so that the heart's response to an increased workload can be evaluated. They should be reassured that the laboratory staff is ready and equipped to handle any emergency should the need arise.
Ideally, preprocedure visits by the physician and a member of the staff in the cardiac catheterization laboratory will provide patients with the information they need about the procedure, its purpose, and potential complications. However, because of anxiety the patient may not be able to assimilate the information and will have many questions not asked at the time of the visits. It is then the responsibility of the floor nurses to answer questions as honestly as they can and to provide emotional support and reassurance.
After the procedure the vital signs are checked periodically. It is especially important to check the pulses distal to the insertion site every half-hour for three hours, or as often as required by protocol, to be sure there has been no clotting and obstruction of a blood vessel. The insertion site dressing is changed as needed and the site inspected for signs of infection. Thirst and diuresis are expected because of the effect of the dye used in the procedure. The patient should be encouraged to drink fluids to prevent hypotension and hasten excretion of the dye, which is potentially nephrotoxic. Mild discomfort also is expected and should respond to the prescribed analgesic. If the patient experiences severe pain the physician should be notified.

catheterization

[kath″ĕ-ter-ĭ-za´shun] 1. passage of a catheter" >catheter into a body channel or cavity. See also cardiac catheterization and central venous catheterization.2. introduction of a catheter via the urethra into the urinary bladder; called also urinary catheterization. This is often a nursing procedure, one that demands strict adherence to the principles of medical and surgical asepsis so that pathogenic microorganisms are not introduced into the urinary system. Since the urinary tract is normally sterile, any break in technique during the insertion of a catheter, or in the care of an indwelling catheter that is left in the bladder for a period of time, may result in a serious infection.Patient Care. About 40 per cent of all nosocomial infections are urinary tract infections" >urinary tract infections, and of these, about 75 per cent are related to urologic instrumentation, usually an indwelling bladder catheter. Prevention of these infections is a challenge to the nursing staff and others concerned with care of the patient.
The smallest gauge catheter that will drain the bladder should always be chosen. It should be inserted gently to avoid trauma, and under sterile conditions to avoid introducing microorganisms into the urinary system. Once an indwelling catheter has been inserted an absolutely closed drainage system must be maintained. Special care must be taken to guard against tension on the catheter and kinking of the tubing, which can obstruct the flow of urine. Catheters should never be pinned to the bedclothing as this can result in accidental removal of the catheter or unnecessary pulling when the patient moves about in bed. The catheter is taped securely to the patient's body. Male, bedridden patients can have the catheter taped to the abdomen to avoid pressure at the junction of the penis and scrotum.
The tubing and collection bag should be arranged so that there is continuous gravity flow of urine. The bag must always be kept below the level of the bladder to avoid backflow of urine into the bladder. It also should never be inverted, for the same reason. This is especially important when the patient is being positioned, helped out of bed, or transported on a stretcher. The catheter should not be clamped nor should it be routinely irrigated and changed. Most authorities agree that catheters need changing only if they are obstructed, if contamination is suspected, or if there is a malfunction of the apparatus. When the collecting bag is being emptied, care must be taken to avoid contamination of the spout.
Patient care must also include attention to the area surrounding the urinary meatus. At least twice daily, or more often if necessary, the genital area should be washed gently with soap and water and dried thoroughly. Crusts and secretions around the catheter may be removed by gentle wiping with a gauze or cotton square saturated with a mild antiseptic. These measures will reduce the possibility of infection and ensure the comfort of the patient by eliminating unpleasant odors and irritation.
Because of the ever-present danger of urinary tract infection, routine orders for catheterization to relieve bladder distention should be avoided and alternatives to an indwelling catheter should be considered. One-time catheterization following surgery may not be necessary if other measures to induce voiding are tried. Patients who require continuous care because of incontinence or an inability to void normally may respond favorably to measures other than indwelling catheterization, such as condom drainage, suprapubic catheter drainage, and, for some carefully selected patients, self-catheterization.cardiac catheterization see cardiac catheterization.central venous catheterization see central venous catheterization.urinary catheterization 1. catheterization (def. 2).2. in the nursing interventions classification, a intervention" >nursing intervention defined as insertion of a catheter into the bladder for temporary or permanent drainage of urine.urinary catheterization: intermittent in the nursing interventions classification, a intervention" >nursing intervention defined as regular periodic use of a catheter to empty the bladder.

cardiac catheterization

Cardiology A procedure in which a flexible catheter is inserted in a peripheral blood vessel, usually a leg–femoral or arm—antecubital vein, passed through the inferior vena cava and, under fluoroscopic guidance, placed in the region(s) of interest Complications Arrhythmias, embolism–cerebral, pulmonary, MI, pericardial tamponade. See Doppler echocardiography.

Cardiac catheterization indications

Evaluate heart valves and detect stenosis and regurgitation Determine regional BP and detect pulmonary HTN Obtain blood samples to evaluate oxygenation of blood Inject dye and evaluate heart function in 'real time'–cardiac angiography and assess patency of the coronary arteries–coronary angiography.

Right-sided cardiac catheterization: Evaluate tricuspid and pulmonary valve function, and measure pressures of and take blood samples from the right atrium and ventricle, and pulmonary artery Abnormalities, right side: Pulmonary HTN, pulmonary valve stenosis, tricuspid valve stenosis, atrial and ventricular septal defects
Left-sided cardiac catheterization: Evaluate function of mitral and aortic valves, and coronary arteries Abnormalities, left side Aortic valve regurgitation, CAD–stenosis or occlusion, mitral valve stenosis or regurgitation, ventricular hypertrophy or aneurysm

cardiac catheterization

The passage of a fine, soft, plastic tube into the heart by way of a vein or artery for the purposes of taking measurements of blood pressure or blood gas concentrations, introducing contrast media for ANGIOGRAPHY, or performing BALLOON VALVOTOMY or ANGIOPLASTY.

单词	cardiac catheterization
释义	cardiac catheterization cardiac catheterization A method of examining or treating conditions of the heart and the arteries by the insertion of a catheter. EncyclopediaSeeCatheterization cardiac catheterization Cardiac Catheterization Definition Cardiac catheterization (also called heart catheterization) is a diagnostic procedure which does a comprehensive examination of how the heart and its blood vessels function. One or more catheters is inserted through a peripheral blood vessel in the arm (antecubital artery or vein) or leg (femoral artery or vein) with x-ray guidance. This procedure gathers information such as adequacy of blood supply through the coronary arteries, blood pressures, blood flow throughout chambers of the heart, collection of blood samples, and x rays of the heart's ventricles or arteries.A test that can be performed on either side of the heart, cardiac catheterization checks for different functions in both the left and right sides. When testing the heart's right side, tricuspid and pulmonary valve function are evaluated, in addition to measuring pressures of and collecting blood samples from the right atrium, ventricle, and pulmonary artery. Left-sided heart catheterization is performed by way of a catheter through an artery which tests the blood flow of the coronary arteries, function of the mitral and aortic valves, and left ventricle. Purpose The primary reason for conducting a cardiac catheterization is to diagnose and manage persons known or suspected to have heart disease, a frequently fatal condition that leads to 1.5 million heart attacks annually in the United States.Symptoms and diagnoses that may lead to performing this procedure include: chest pain, characterized by prolonged heavy pressure or a squeezing pain abnormal treadmill stress test myocardial infarction, also known as a heart attack congenital heart defects, or heart problems that originated from birth a diagnosis of valvular-heart disease a need to measure the heart muscle's ability to pump blood Typically performed along with angiography, a technique of injecting a dye into the vascular system to outline the heart and blood vessels, a catheterization can aid in the visualization of any blockages, narrowing, or abnormalities in the coronary arteries. If these signs are visible, the cardiologist may assess the patient's need and readiness for coronary bypass surgery, or perhaps a less invasive approach, such as dilation of a narrowed blood vessel either surgically or with the use of a balloon (angioplasty).When looking at the left side of the heart, fluoroscopic guidance also allows the following diagnoses to be assessed: enlargement of the left ventricle ventricular aneurysms (abnormal dilation of a blood vessel) narrowing of the aortic valve insufficiency of the aortic or mitral valve the detour of blood from one side of the heart to the other due to septal defects (also known as shunting) Precautions Cardiac catheterization is categorized as an "invasive" procedure which involves the heart, its valves, and coronary arteries, in addition to a large artery in the arm or leg. Due to the nature of the test, it is important to evaluate for the following conditions before considering this procedure: A diagnosis of a bleeding disorder, poor kidney function, or debilitation. Any of these pre-existing conditions typically raises the risk of the catheterization procedure and may be reason to cancel the procedure. A diagnosis of heart valve disease. If this is detected, antibiotics may be given before the test to prevent inflammation of the membrane which lines the heart (endocarditis). Description To understand how a cardiac catheterization is able to diagnose and manage heart disease, the basic workings of the heart muscle must also be understood. Just as the body relies on a constant supply of blood to aid in its everyday functions, so does the heart. The heart is made up of an intricate web of blood vessels (coronary arteries) that ensure an adequate supply of blood rich in oxygen and nutrients. It is easy to see how an abnormality in any of these arteries can be detrimental to the heart's function. These abnormalities cause the heart's blood flow to decrease and result in the condition known as coronary artery disease or coronary insufficiency.Catheterization is a valuable tool in detecting and treating abnormalities of the heart. Through the use of fluoroscopic (x ray) guidance, a catheter, which may resemble a balloon-tipped tube, is strung through the veins or arteries into the heart, so the cardiologist can monitor a body's various functions at each moment.Generally a test that lasts two to three hours, a patient should expect the following prior to and during the catheterization procedure: A mild sedative may be given that will allow the patient to relax but remain conscious during the test. An intravenous needle will be inserted in the arm to administer medication. Electrodes will be attached to the chest to enable the painless procedure known as an electrocardiograph. Prior to inserting a catheter into an artery or vein in the arm or leg, the incision site will be made numb by injecting a local anesthetic. When the anesthetic is injected it may feel like a pin-prick followed by a quick stinging sensation. Pressure may also be experienced as the catheter travels through the blood vessel. After the catheter is guided into the coronary-artery system, a dye (also called a radiocontrast material) is injected to aid in the identification of any abnormalities of the heart. During this time, the patient may experience a hot, flushed feeling or a quickly passing nausea. Coughing or breathing deeply aids in any discomfort. Medication may be given during the procedure if chest pain is experienced, and nitroglycerin may also be administered to allow expansion of the heart's blood vessels. When the test is complete, the physician will remove the catheter and close the skin with several sutures or tape. Preparation Prior to the cardiac catheterization procedure, it is important to relay information to the physician or nurse regarding allergies to shellfish (such as shrimp or scallops) which contain iodine, iodine itself, or the dyes that are commonly used in other diagnostic tests.Because this procedure is categorized as a surgery, the patient will be instructed not to eat or drink anything for at least six hours prior to the test. Just before the test begins, the patient will urinate and change into a hospital gown, then lie flat on a padded table that may also be tilted in order for the heart to be examined from a variety of angles. Aftercare While cardiac catheterization may be performed on an out-patient basis, a patient may require close monitoring following the procedure while remaining in the hospital for at least 24 hours. The patient will be instructed to rest in bed for at least eight hours immediately after the test. If the catheter was inserted into a vein or artery in the leg or groin area, the leg will be kept extended for four to six hours. If a vein or artery in the arm was used to insert the catheter, the arm will need to remain extended for a minimum of three hours.The patient should expect a hard ridge to form over the incision site that diminishes as the site heals. Bluish discoloration under the skin at the point of insertion should also be expected but fades in two weeks. It is also not uncommon for the incision site to bleed during the first 24 hours following surgery. If this should happen, the patient should apply pressure to the site with a clean tissue or cloth for 10-15 minutes.Aftercare (Illustration by Argosy Inc.) Risks Similar to all surgical procedures, the cardiac catheterization test does involve some risks. Complications that may occur during the procedure include cardiac arrhythmias (an irregular heart beat) pericardial tamponade (a condition that causes excess pressure in the pericardium which affects the heart due to accumulation of excess fluid) the rare occurrence of myocardial infarction (heart attack) or stroke may also develop due to clotting or plaque rupture of one or more of the coronary or brain arteries. Before left-side catheterization is performed, the anticoagulant medication heparin may be administered. This drug helps decrease the risk of the development of a blood clot in an artery (thrombosis) and blood clots traveling throughout the body (embolization).The risks of the catheterization procedure increase in patients over the age of 60, those who have severe heart failure, or persons with serious valvular heart disease. Normal results Normal findings from a cardiac catheterization will indicate no abnormalities of heart chamber size or configuration, wall motion or thickness, the direction of blood flow, or motion of the valves. Smooth and regular outlines on the x ray indicate normal coronary arteries.An essential part of the catheterization is measuring intracardiac pressures, or the pressure in the heart's chambers and vessels. Pressure readings that are higher than normal are significant for a patient's overall diagnosis. The pressure readings that are lower, other than those which are produced as a result of shock, typically are not significant.An ejection fraction, or a comparison of how much blood is ejected from the heart's left ventricle during its contraction phase with a measurement of blood remaining at the end of the left ventricle's relaxation phase, is also determined by performing a catheterization. The cardiologist will look for a normal ejection fraction reading of 60-70%. Abnormal results Cardiac catheterization provides valuable still and motion x-ray pictures of the coronary arteries that help in diagnosing coronary artery disease, poor heart function, disease of the heart valves, and septal defects (a defect in the septum, the wall that separates two heart chambers).The most prominent sign of coronary artery disease is the narrowing or blockage in the coronary arteries, with narrowing that is greater than 70% considered significant. A clear indication for intervention (by angioplasty or surgery) is a finding of significant narrowing of the left main coronary artery and/or blockage or severe narrowing in the high, left anterior descending coronary artery.A finding of impaired wall motion is an additional indicator of coronary artery disease, aneurysm, an enlarged heart, or a congenital heart problem. Using the findings from an ejection fraction test which measures wall motion, cardiologists look at an ejection fraction reading under 35% as increasing the risk of complications while also decreasing a successful long term or short term outcome with surgery.Detecting the difference in pressure above and below the heart valve can verify heart valve disease. The greater narrowing correlates with the higher pressure difference.To confirm septal defects, a catheterization measures oxygen content on both the left and right sides of the heart. The right heart pumps unoxygenated blood to the lungs, and the left heart pumps blood that contains oxygen from the lungs to the rest of the body. Right side elevated oxygen levels indicate left-to-right atrial or ventricular shunt. A left side that experiences decreased oxygen indicates a right-to-left shunt. Resources Organizations American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org.National Heart, Lung and Blood Institute. P.O. Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. http://www.nhlbi.nih.gov. Key terms Aneurysm — An abnormal dilatation of a blood vessel, usually an artery. It can be caused by a congenital defect or weakness in the vessel's wall.Angiography — In cardiac catheterization, a picture of the heart and coronary arteries is seen after injecting a radiopaque substance (often referred to as a dye) throughout the veins and arteries.Angioplasty — An alternative to vascular surgery, a balloon catheter is used to mechanically dilate the affected area of the artery and enlarge the constricted or narrowed segment.Aortic valve — The valve between the heart's left ventricle and ascending aorta that prevents regurgitation of blood back into the left ventricle.Catheter — A tube made of elastic, elastic web, rubber, glass, metal, or plastic used to evacuate or inject fluids into the body. In cardiac catheterization, a long, fine catheter is used for passage through a blood vessel into the chambers of the heart.Coronary bypass surgery — A surgical procedure which places a shunt to allow blood to travel from the aorta to a branch of the coronary artery at a point past an obstruction.Left anterior descending coronary artery (LAD) — One of the heart's coronary artery branches from the left main coronary artery which supplies blood to the left ventricle.Mitral valve — The bicuspid valve which is between the left atrium and left ventricle of the heart.Pulmonary valve — The heart valve which is positioned between the right ventricle and the opening into the pulmonary artery.Shunt — A passageway (or an artificially created passageway) that diverts blood flow from one main route to another.Tricuspid valve — The right atrioventricular valve of the heart. cardiac [kahr´de-ak] 1. pertaining to the heart" >heart.2. pertaining to the ostium cardiacum" >ostium cardiacum.cardiac arrest sudden and often unexpected stoppage of effective heart action. Either the periodic impulses that trigger the coordinated heart muscle contractions cease or fibrillation" >ventricular fibrillation or flutter occurs in which the individual muscle fibers have a rapid irregular twitching. The majority of victims of cardiac arrest suffer from ventricular fibrillation, and most have severe coronary artery disease. The only chance for survival for many who have unexpected cardiac arrest is successful implementation of emergency cardiac care and cardiopulmonary resuscitation (CPR). Reduction of the incidence of cardiac arrest and sudden death is a major concern of the American Heart Association and the American Red Cross. Programs aimed at achieving the goal of reduced mortality from cardiac arrest include education of the general public in ways to avoid the development of coronary artery disease in the first place, and secondarily, training lay people and health care professionals and paraprofessionals in the techniques of CPR and emergency cardiac care. Although cardiac arrest usually is related to preexisting coronary artery disease, there are other events in which the prompt delivery of CPR alone could mean survival for the victim. These include the cessation of heart and lung action as a result of drowning, suffocation, electrocution, drug overdose, and severe accidental trauma.cardiac catheterization the insertion of a catheter into a vein or artery and guiding of it into the interior of the heart for purposes of measuring cardiac output, determining the oxygen content of blood in the heart chambers, and evaluating the structural components of the heart. It is indicated whenever it is necessary to establish a precise and definite diagnosis in order to determine whether heart surgery is necessary and to plan the surgical approach. A, Right-sided heart catheterization. The catheter is inserted into the femoral vein and advanced through the inferior vena cava (or, if into an antecubital or basilic vein, through the superior vena cava), right atrium, and right ventricle and into the pulmonary artery. B, Left-sided heart catheterization. The catheter is inserted into the femoral artery or the antecubital artery. The catheter is passed through the ascending aorta, through the aortic valve, and into the left ventricle. From Ignatavicius and Workman, 2002.Patient Care. Patients scheduled for cardiac catheterization experience a high level of stress. They are fearful and anxious because the procedure involves the heart, has a potential for some rather serious complications, and could indicate a need for cardiac surgery. Prior to the catheterization the patient will need to know that it is not a surgical procedure, even though a consent form must be signed, food and fluids are restricted, and a surgical preparation of the catheter insertion site is done. The patient should be told of these and other preparations as well as the physical features of the laboratory in which the catheterization is to be done. During the initial assessment it is important to find out whether the patient has any allergies. The contrast medium used contains iodide salts; if a patient is allergic to iodine or seafood, a contrast medium that does not contain iodine must be used, or antihistamines must be administered before the procedure. A mild tranquilizer or hypnotic may be given just before the procedure to help the patient relax, but a general anesthetic is not used. Patients need to know that they must be awake and cooperative during the procedure. They will be asked to stay in a certain position, cough, breathe deeply, and possibly exercise so that the heart's response to an increased workload can be evaluated. They should be reassured that the laboratory staff is ready and equipped to handle any emergency should the need arise. Ideally, preprocedure visits by the physician and a member of the staff in the cardiac catheterization laboratory will provide patients with the information they need about the procedure, its purpose, and potential complications. However, because of anxiety the patient may not be able to assimilate the information and will have many questions not asked at the time of the visits. It is then the responsibility of the floor nurses to answer questions as honestly as they can and to provide emotional support and reassurance. After the procedure the vital signs are checked periodically. It is especially important to check the pulses distal to the insertion site every half-hour for three hours, or as often as required by protocol, to be sure there has been no clotting and obstruction of a blood vessel. The insertion site dressing is changed as needed and the site inspected for signs of infection. Thirst and diuresis are expected because of the effect of the dye used in the procedure. The patient should be encouraged to drink fluids to prevent hypotension and hasten excretion of the dye, which is potentially nephrotoxic. Mild discomfort also is expected and should respond to the prescribed analgesic. If the patient experiences severe pain the physician should be notified. catheterization [kath″ĕ-ter-ĭ-za´shun] 1. passage of a catheter" >catheter into a body channel or cavity. See also cardiac catheterization and central venous catheterization.2. introduction of a catheter via the urethra into the urinary bladder; called also urinary catheterization. This is often a nursing procedure, one that demands strict adherence to the principles of medical and surgical asepsis so that pathogenic microorganisms are not introduced into the urinary system. Since the urinary tract is normally sterile, any break in technique during the insertion of a catheter, or in the care of an indwelling catheter that is left in the bladder for a period of time, may result in a serious infection.Patient Care. About 40 per cent of all nosocomial infections are urinary tract infections" >urinary tract infections, and of these, about 75 per cent are related to urologic instrumentation, usually an indwelling bladder catheter. Prevention of these infections is a challenge to the nursing staff and others concerned with care of the patient. The smallest gauge catheter that will drain the bladder should always be chosen. It should be inserted gently to avoid trauma, and under sterile conditions to avoid introducing microorganisms into the urinary system. Once an indwelling catheter has been inserted an absolutely closed drainage system must be maintained. Special care must be taken to guard against tension on the catheter and kinking of the tubing, which can obstruct the flow of urine. Catheters should never be pinned to the bedclothing as this can result in accidental removal of the catheter or unnecessary pulling when the patient moves about in bed. The catheter is taped securely to the patient's body. Male, bedridden patients can have the catheter taped to the abdomen to avoid pressure at the junction of the penis and scrotum. The tubing and collection bag should be arranged so that there is continuous gravity flow of urine. The bag must always be kept below the level of the bladder to avoid backflow of urine into the bladder. It also should never be inverted, for the same reason. This is especially important when the patient is being positioned, helped out of bed, or transported on a stretcher. The catheter should not be clamped nor should it be routinely irrigated and changed. Most authorities agree that catheters need changing only if they are obstructed, if contamination is suspected, or if there is a malfunction of the apparatus. When the collecting bag is being emptied, care must be taken to avoid contamination of the spout. Patient care must also include attention to the area surrounding the urinary meatus. At least twice daily, or more often if necessary, the genital area should be washed gently with soap and water and dried thoroughly. Crusts and secretions around the catheter may be removed by gentle wiping with a gauze or cotton square saturated with a mild antiseptic. These measures will reduce the possibility of infection and ensure the comfort of the patient by eliminating unpleasant odors and irritation. Because of the ever-present danger of urinary tract infection, routine orders for catheterization to relieve bladder distention should be avoided and alternatives to an indwelling catheter should be considered. One-time catheterization following surgery may not be necessary if other measures to induce voiding are tried. Patients who require continuous care because of incontinence or an inability to void normally may respond favorably to measures other than indwelling catheterization, such as condom drainage, suprapubic catheter drainage, and, for some carefully selected patients, self-catheterization.cardiac catheterization see cardiac catheterization.central venous catheterization see central venous catheterization.urinary catheterization 1. catheterization (def. 2).2. in the nursing interventions classification, a intervention" >nursing intervention defined as insertion of a catheter into the bladder for temporary or permanent drainage of urine.urinary catheterization: intermittent in the nursing interventions classification, a intervention" >nursing intervention defined as regular periodic use of a catheter to empty the bladder. cardiac catheterization Cardiology A procedure in which a flexible catheter is inserted in a peripheral blood vessel, usually a leg–femoral or arm—antecubital vein, passed through the inferior vena cava and, under fluoroscopic guidance, placed in the region(s) of interest Complications Arrhythmias, embolism–cerebral, pulmonary, MI, pericardial tamponade. See Doppler echocardiography. Cardiac catheterization indications Evaluate heart valves and detect stenosis and regurgitation Determine regional BP and detect pulmonary HTN Obtain blood samples to evaluate oxygenation of blood Inject dye and evaluate heart function in 'real time'–cardiac angiography and assess patency of the coronary arteries–coronary angiography. Right-sided cardiac catheterization Evaluate tricuspid and pulmonary valve function, and measure pressures of and take blood samples from the right atrium and ventricle, and pulmonary artery Abnormalities, right side: Pulmonary HTN, pulmonary valve stenosis, tricuspid valve stenosis, atrial and ventricular septal defects Left-sided cardiac catheterization Evaluate function of mitral and aortic valves, and coronary arteries Abnormalities, left side Aortic valve regurgitation, CAD–stenosis or occlusion, mitral valve stenosis or regurgitation, ventricular hypertrophy or aneurysm cardiac catheterization The passage of a fine, soft, plastic tube into the heart by way of a vein or artery for the purposes of taking measurements of blood pressure or blood gas concentrations, introducing contrast media for ANGIOGRAPHY, or performing BALLOON VALVOTOMY or ANGIOPLASTY. AcronymsSeecruiserThesaurusSeecatheterization
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