Capillary

Capillaries are the smallest blood vessel in the body, with walls only one cell thick. Capillaries run throughout the body, passing oxygen, nutrients, and other substances through their walls to the tissue beds and taking carbon dioxide and other waste products from the tissue beds back into the blood stream.

Cardiac Arrest

Cardiac arrest, or a heart attack, is when the heart stops pumping blood through the body. This can occur because the ventricles are beating too erratically to effectively pump any blood (ventricular fibrillation), or because the heart stops beating at all (asystole). Heart attack victims quickly lose consciousness, their pulse disappears, and they stop breathing. Emergency measures include CPR (cardiopulmonary resuscitation) and defibrillation.

Cardiac Catherization Lab

The X-ray room where coronary angiograms and angioplasties are performed in hospitals. Also known as the cath lab.

Cardiac Catheterization

Procedures used to study the various functions of the heart. Using different techniques, the coronary arteries can be viewed by injecting dye or opened using balloon angioplasty.

Cardiac Muscle

Cardiac muscle (see also myocardium) comprises most of the walls of the heart, making the powerful contractions that pump blood throughout the body. It is a special form of muscle which can work continuously.

Cardiac Reflex

The walls of the heart contain sensory fibers that alert the brain when the heart is beating faster than normal. The brain then sends a message through the vagus nerve which tells the heart to beat more slowly. This process of self-monitoring is referred to as the cardiac reflex.

Cardiogenic Shock

Cardiogenic shock occurs when the heart cannot pump enough blood to maintain a normal body blood pressure. Results from this severe condition include fainting, organ failure, coma, and death.

Cardiomyopathy

Cardiomyopathy is any chronic disorder affecting the heart muscle. Possible conditions caused by cardiomyopathy include enlargement of the heart, heart failure, arrhythmias, and embolisms.

Cardioplegia

Cardioplegia is a potassium-salt solution used to intentionally stop the heart in order to perform bypass surgery or a transplant. Other methods of stopping the heart include cooling the heart and using an electrical shock.

Cardiopulmonary Bypass

During cardiopulmonary bypass, the function of the heart and lungs are taken over temporarily by a machine. This heart-lung machine maintains circulation throughout the body during open-heart surgery. Blood is taken out of the body from the superior and inferior venae cavae, pumped through the machine and oxygenated and then circulated back into the body through a major artery.

Cardiotocography

Cardiotocography is the monitoring of a fetal heart rate.

Cardiotomy Syndrome (Dressler's Syndrome)

A possible complication of heart surgery, cardiotomy syndrome is an autoimmune condition that results in fever, pericarditis, and possibly pneumonia. Treatment includes anti-inflammatory drugs.

Cardiovascular

The circulatory system - consisting of the heart and blood vessels which carries nutrients and oxygen to the tissues of the body and removes carbon dioxide and other wastes from them.

Cardiovascular Disease

Disease affecting the heart or blood vessels. Cardiovascular diseases include arteriosclerosis, coronary artery disease, heart valve disease, arrhythmia, heart failure, hypertension, orthostatic hypotension, endocarditis, diseases of the aorta and its branches, disorders of the peripheral vascular system, and congenital heart disease.

Cardiovascular System

The cardiovascular system refers to the heart and all the blood vessels.

Cardioversion

Cardioversion is a controlled electrical shock (from a machine called a defibrillator) applied to the chest wall of a patient. It is used to return to normal the heart beat of a patient suffering from arrhythmia. Recently, implantable devices (automatic implantable cardiac defibrillators, AICD) that automatically shock the heart in case of distress have been placed into patients who have been previously saved by cardioversion.

Carotid Artery

The carotid artery supplies blood to the head and neck. The left common carotid artery branches directly off the aortic arch. The right common carotid artery branches off the brachiocephalic artery.

Catheter

A thin plastic tube used to access various parts of the body, such as the coronary arteries. A treatment device - such as a stent - is often attached to the catheter.

Cholesterol

Cholesterol is a waxy, fat related compound in the body tissues and organs of man and animal, cholesterol plays a vital role in metabolism. However, cholesterol is a key part in the creation of fatty deposits in the arterial walls and an increased blood cholesterol is a risk factor in coronary artery disease. Cholesterol is found only in foods of animal origin. It is recommended that the daily intake of dietary cholesterol be no more than 200 - 300 mg. per day.

Congenital

A congenital defect is a defect in any organ present at birth.

Congestive Heart Failure, Chf

Congestive heart failure refers to a global failing of the heart muscle. After the heart muscle ceases to work, fluid accumulates in the lungs and body. Among the possible consequences of CHF are an inability to breathe, liver failure, hypotension, myocardial infarction, and death. CHF is treated with diuretics or, in severe cases, a heart transplant.

Coronary

Related to arteries that supply blood and nutrients to the heart.

Coronary Angiogram

A test to determine if coronary artery disease is present. Contrast dye is injected into the coronary arteries and a fluoroscope allows clinicians to see the vessels on an X-ray screen.

Coronary Angioplasty

A coronary angioplasty is a procedure in which a deflated balloon is guided into a section of clogged artery through an X-Ray guided cardiac catheter. Once the balloon reaches the selected section it is inflated, thereby expanding the clogged area and permitting an increased blood flow. If a coronary angioplasty does not work, a coronary bypass graft may be necessary. (See also stent.)

Coronary Arteries

The arteries that surround the heart and supply blood containing oxygen and nutrients to the heart muscle.

Coronary Artery

The coronary arteries are the arteries that wrap around the heart, providing the heart with its own blood supply. There are two coronary arteries, the right and left, which both branch off from the aorta.

Coronary Artery Bypass Graft (Cabg)

A coronary artery bypass graft is a surgical procedure whereby a blocked section of artery is literally "bypassed" by attaching a healthy segment of blood vessel around the diseased area. Both arteries and veins (which are converted into arteries) may be used to "bypass" the blocked coronary segments. Arteries and veins are taken from elsewhere in the patient's body, most commonly the internal mammary arteries from the inside of the front of the chest or the saphenous veins from the legs. (To learn about the surgical procedure for CABGs, please see the Procedures section).

Coronary Artery Bypass Graft Surgery (CABG)

The medical term for heart bypass surgery. This surgery is carried out to relieve angina (chest pain or discomfort caused by reduced blood supply to the heart) by creating a bypass around blocked or narrowed coronary arteries. The bypass itself is a short length of artery or vein taken from the leg or chest and grafted onto the heart above and below the blocked artery.

Coronary Artery Disease (CAD)

Disease affecting the coronary arteries that surround the heart and supply blood to the heart muscle. It occurs when the lumen of the coronary arteries becomes narrowed with plaque deposits (a build-up of cholesterol and other fats, calcium and other elements carried in the blood).

Coronary Revascularization

Revascularization refers to the medical process of restoring healthy blood flow to the heart muscle. Traditionally revascularization has fallen into two distinctive categories: Coronary Artery Bypass Graft and Angioplasty. Recently a new revascularization technique, Minimally Invasive Direct Coronary Artery Bypass, MIDCAB, surgery has been developed. Both CABG and MIDCAB are surgical procedures in which the blocked segment of artery is "bypassed" with a segment of healthy artery or vein. Angioplasty is an interventional, non-surgical, procedure that opens the clogged section of artery instead of bypassing it surgically.

Coronary Sinus

Oxygen-poor blood pools in the coronary sinus before flowing into the right atrium. This blood originates in the coronary arteries, where the heart muscle consumes its oxygen.

Coronary Thrombosis

A coronary thrombus is a blood clot (thrombus) that forms in the coronary artery, usually at the site of an atheroma, blocking the supply of blood to a section of the heart. This lack of blood may cause a myocardial infarction, or the death of that section of the heart muscle.

Ct Scan/Computed Tomography

Computed Tomography, commonly referred to as a CT scan, takes X-ray "slice" images of the human body and the uses a computer to create a composite cross-sectional image.

Cyanosis

Cyanosis occurs when oxygen-poor blood is introduced into the arteries, which normally only carry oxygen-rich blood. Its name comes from the blue tint that appears in the patient's skin when this condition occurs. (Oxygen-poor blood is blue in color. Cyan is from the Greek word for blue.)