D

DASH eating plan The acronym for “dietary
approaches to stop HYPERTENSION.” The DASH eat-
ing plan is the result of a pair of clinical research
studies and features a diet high in fruits, vegeta-
bles, low-fat dairy products, whole grain products,
and low in fats (particularly saturated fats) and
sodium. Numerous studies correlate dietary habits,
particularly sodium consumption, with hyperten-
sion. The DASH eating plan is appropriate for any-
one to follow to maintain cardiovascular health.
The plan, available through health-care providers
and online from the National Heart, Lung, and
Blood Institute (NHLBI) at http://www.nhlbi.nih.gov,
features menus and extensive food choices to help
people plan nutritious meals that help lower
BLOOD PRESSURE. It also provides guidelines for
transitioning to more heart-healthy eating and
other lifestyle habits.
See also CARDIOVASCULAR DISEASE PREVENTION; DIET
AND CARDIOVASCULAR HEALTH; EATING HABITS; PHYSICAL
EXERCISE AND CARDIOVASCULAR HEALTH.

defibrillation A therapeutic method for deliver-
ing an electrical shock to the HEARTto restore it to
a functional rhythm. Defibrillation is an emer-
gency treatment necessary to prevent death
resulting from VENTRICULAR FIBRILLATION(rapid, dis-
cordant, and ineffective contractions that fail to
pump BLOODout of the heart). The body cannot
survive in ventricular fibrillation for longer than a
few minutes, making rapid response essential. The
most common causes of ventricular fibrillation are
MYOCARDIAL INFARCTION, arrhythmic cardiac disease
such as LONGQT SYNDROME(LQTS), ELECTROCUTION,
and drowning.
In hospital-based defibrillation, a health-care
professional (usually a doctor) places paddles or
electrodes on the outside of the chest. The defibril-

lator machine delivers the determined electrical

impulse, generally producing a pronounced jolt in

the person’s body. The desired effect is for all elec-

trical activity in the heart to momentarily cease,

then for the heart to resume normal electrical

activity to the extent possible in the context of

damage that may have occurred to the heart. The

doctor may choose to administer multiple charges,

depending on the response and the likelihood for

successful restoration of a regular HEART RATE.

In the 1990s a basic portable device, the AUTO-

MATED EXTERNAL DEFIBRILLATOR(AED) became avail-

able. AEDs allow virtually anyone to administer a

potentially lifesaving electrical shock to someone

who is experiencing ventricular fibrillation. The

computerized programming of an AED reads the

ELECTROCARDIOGRAM(ECG) of the person to confirm

the ventricular fibrillation, then delivers a preset

electrical shock. AEDs have saved countless lives.

The risks of defibrillation include electrical

BURNSto the person being resuscitated and electri-

cal shock or burns to the person administering

defibrillation. Burns may occur at the contact

points of the paddles or electrodes and also else-

where on the body where there are items of metal

such as jewelry or, in a hospital setting, monitor-

ing electrodes. As well, anyone in contact with the

person or with the bed the person is lying on is at

risk for contact electrical shock. The success of

defibrillation depends on the cause of the ventric-

ular fibrillation, how long the heart has been in

ventricular fibrillation, and the person’s overall

cardiovascular and general health status.

See also ARRHYTHMIA; CARDIOPULMONARY RESUSCI-

TATION(CPR); CARDIOVERSION.

deep vein thrombosis (DVT) The formation of

BLOODclots in the veins, usually the deep or inte-

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