Carcinoma, Merkel cell: An infrequent but highly malignant type of skin cancer. Characteristically starts in a sun-exposed area (of the head, neck, arms or legs) in whites 60-80 years of age as a firm, painless, shiny lump that can be red, pink, or blue in color and vary in size from less than a quarter of an inch (a half cm) to more than two inches (5 cm) in diameter. The tumor grows rapidly and often metastasizes (spreads) to other parts of the body. Even relatively small tumors are capable of metastasis, particularly to the regional (nearby) lymph nodes. Merkel cell carcinoma follows an aggressive course like that of melanoma, and has a predilection to spread to (in order of frequency) liver, bone, brain, lung, and skin. The prognosis (outlook) is accordingly poor.
“Merkel” is often misspelled as “Merkle.” The disease is named for the German anatomist and pathologist Friedrich Sigmund Merkel (1845-1919) and is also called neuroendocrine carcinoma of the skin.
- CARDIA Study
CARDIA Study: Coronary Artery Risk Development In Young Adults (CARDIA). A study designed to increase understanding of contributors to changes in cardiovascular disease (CVD) risk factors during the critical years of transition from adolescence through young adulthood to middle age. CARDIA was funded by National Heart, Lung, and Blood Institute (NHLBI), a part of the […]
- Cardiac aneurysm
Cardiac aneurysm: An outpouching of an abnormally thin portion of the heart wall. Cardiac aneurysms tend to involve the left ventricle because the blood there is under the greatest pressure.
- Cardiac conduction system
Cardiac conduction system: The electrical conduction system that controls the heart rate. This system generates electrical impulses and conducts them throughout the muscle of the heart, stimulating the heart to contract and pump blood. Among the major elements in the cardiac conduction system are the sinus node, atrioventricular node, and the autonomic nervous system. The […]
- Cardiac defibrillator, implantable
Cardiac defibrillator, implantable: A device that is designed to be put in the body to recognize certain types of abnormal heart rhythms (arrhythmias) and correct them by delivering precisely calibrated and timed electrical shocks to restore a normal heartbeat. Defibrillators continuously monitor the heart rhythm in order to detect overly rapid life-threatening arrhythmias, such as […]
- Cardiac index
Cardiac index: A cardiodynamic measure based on the cardiac output, which is the amount of blood the left ventricle ejects into the systemic circulation in one minute, measured in liters per minute (l/min). Cardiac output is indexed to a patient’s body size by dividing by the body surface area to yield the cardiac index.