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D

DEFIBRILLATION Defibrillation is the use of strong but controlled electric shocks to return the heart to a normal rhythm of contractions. Defibrillation is used when the ventricles of patient's heart are beating too quickly or erratically to effectively pump blood (ventricular fibrillation). The electrical shocks are applied by a machine called a defibrillator either through electrodes on the chest wall of a patient, or directly to the patient's heart. See also Automatic Implantable Cardiac Defibrillators, AICDs.

DESCENDING AORTA The descending aorta begins after the aorta arches over the heart. The descending aorta travels down along the spine. The section of the descending aorta from the aortic arch to the diaphragm is also called the thoracic aorta. The section of the descending aorta below the diaphragm is also called the abdominal aorta.

DIASTOLE The period of diastole is when the ventricle relaxes between contractions. When a patient's blood pressure is taken, the diastolic pressure, or the measurement of this resting period, is the second figure given. An average diastole lasts roughly 0.5 seconds for a heart rate of 70 beats per minute.

DIRECTIONAL CORONARY ATHERECTOMY (DCA) A directional coronary atherectomy is similar to an angioplasty except that the blockage is decreased by mechanically removing the plaque.

DRESSLER’S SYNDROME See cardiotomy syndrome.

E

ECHOCARDIOGRAM (ECHO) An echocardiogram is a picture of the heart taken using sound waves. This image gives information about the structure and function of the heart.

ECTOPIC BEAT (EXTRASYSTOLE) An ectopic beat is a premature heartbeat due to a contraction impulse from an abnormal source. Normally the sinoatrial node starts the contraction process. With an ectopic beat, however, either a source in the atria (supraventricular) or a source in the ventricles (ventricular) may initiate the contraction. Among the causes of ectopic beats are heart disease, smoking, and caffeine.

EDEMA Edema is swelling caused by excess fluid accumulated in body tissues. (Edema was formerly known as dropsy.) Possible results range from swollen limbs to heart failure, depending on the extent and location of the swelling. Edema in the lungs is known as pulmonary edema and is life threatening.

ELECTROCARDIOGRAM (EKG/ECG) An electrocardiogram is a recording of the electrical activity of the heart taken by a machine called an electrocardiograph.

ELECTROPHYSIOLOGY STUDIES Electrophysiology studies are done to determine the focus or focii of arrhythmias in the heart. During cardiac catheterization, small electrodes are placed in the heart and the electrical potential of the heart can be measured internally. This allows the physician to find an area of abnormal electrical conductance responsible for an arrhythmia and ablate it (kill off the abnormal cells).

EMBOLISM An embolism is when an embolus - a traveling clot of blood, fat, air, or other substance - lodges in an artery and blocks the blood flow. Pulmonary embolisms (clots in the pulmonary artery) are the most common. An embolus which goes to the brain can cause a stroke.

EMBOLUS An embolus is a clot of blood, fat, air, or some other substance that travels through the bloodstream, lodging in small vessels.

ENDOCARDITIS Endocarditis is an inflammation of the endocardium (the lining of the heart) and valves. Frequently caused by a bacterial infection or rheumatic fever, symptoms include fever, embolism, changing heart murmurs, and heart failure.

ENDOCARDIUM The endocardium is the delicate inner lining of the heart, which also covers the arteries, veins and valves. The cusps of the valves are formed from folds of this linings.

ENDOMYOCARDITIS Endomyocarditis is an inflammation of the muscle and lining membrane of the heart, frequently caused by a viral infection or rheumatic fever. Symptoms include arrhythmias, enlargement of the heart, murmurs, and embolisms. (If the pericardium, the sac surrounding the heart, is also inflamed then the diagnosis is pancarditis.)

EPICARDIUM The epicardium is both the outer layer of the heart and the inner layer of the pericardium (the sac surrounding the heart).

F

FAT Fat is an essential nutrient used by the body for many functions including energy, thermal insulation, vital organ protection, cell structure, and function. It is recommended that less than 30% of food calories come from dietary fats, which are present in foods of both animal and vegetable origin. (See also Saturated Fat; Monounsaturated Fat; Polyunsaturated Fat; and Omega-3 Fatty Acids.)

FEMORAL ARTERY The femoral artery starts at the top of the thigh, runs along the front, before passing to the back of the thigh, and running behind the knee.

FIBRILLATION Fibrillation is when the heart beats so quickly and chaotically that it cannot effectively pump blood. Atrial fibrillation is a frequent cause of arrhythmia and often stems from hypertensive heart disease or pericarditis. It can usually be treated with drug therapy. Ventricular fibrillation is a much more serious condition, which can lead to cardiac arrest or death of heart muscle (myocardial infarction).