Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «H»:
Hearing aid: An instrument to help in hearing. There are four common styles of hearing aids.
From largest to smallest, they are:
Behind-the-ear (BTE) hearing aids,
In-the-ear (ITE) hearing aids,
In-the-canal (ITC) hearing aids, and
Completely-in-the-canal (CIC) hearing aids.
There is also a bod...
Hearing instrument: A synonym for a hearing aid that gained popularity to distinguish the device from AIDS. See: Hearing aid....
Hearing loss, age-related
Hearing loss, age-related: See: Presbycusis....
Hearing screening test, newborn
Hearing screening test, newborn: Screening of the newborn baby's ability to hear. Newborn screening of hearing is done with automated auditory brainstem response tests or, less often, with what are called otoacoustic emission or conventional auditory brainstem response tests. The aim is to detect th...
Heart: The muscle that pumps blood received from
veins into arteries throughout the body. It is positioned in the
chest behind the sternum (breastbone; in front of the trachea,
esophagus, and aorta; and above the diaphragm muscle that separates
the chest and abdominal cavities. The normal heart ...
Heart and hand syndrome
Heart and hand syndrome: See: Holt-Oram syndrome....
Heart attack: The death of heart muscle due to the
loss of blood supply. The loss of blood supply is usually caused by
a complete blockage of a coronary artery, one of the arteries that supplies blood to the heart muscle. Death of
the heart muscle, in turn, causes chest pain and electrical instab...
Heart block: A block in the conduction of the normal electrical
impulses in the heart. ...
Heart conduction system
Heart 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...
Heart disease: Any disorder that affects the heart. Sometimes the term "heart disease" is used narrowly and incorrectly as a synonym for coronary artery disease. Heart disease is synonymous with cardiac disease but not with cardiovascular disease which is any disease of the heart or blood vessels...
Heart disease, rheumatic
Heart disease, rheumatic: Heart damage caused by
rheumatic fever. Treatment is by preventing reinfection with strep and by treating
with heart drugs as needed....
Heart failure: Inability of the heart to
keep up with the demands on it and, specifically, failure of the
heart to pump
blood with normal
efficiency. When this occurs,
the heart is unable to provide adequate blood
flow to other organs such as the brain, liver and kidneys. Heart
failure may be...
Heart murmur: An extra abnormal heart sound usually detected while listening
to the heartbeat with a stethoscope. Heart murmurs may be harmless or may signal
a problem, such as an abnormality of the heart valves or a
congenital (present at birth) heart disease....
Heart muscle: A type of muscle with unique features only found in the heart. The heart muscle, or cardiac muscle, is medically called the myocardium ("myo-" being the prefix denoting muscle)....
Heart rate: The number of
heart beats per unit time,
usually per minute. The heart rate is based on the number of contractions of the
ventricles (the lower chambers of the heart). The heart rate may be too fast (tachycardia)
or too slow (bradycardia). The pulse is bulge of an artery from the wave ...