Encyclopedia of Health and Medicine

D
DASH eating plan The acronym for “dietary
approaches to stop HYPERTENSION.” The DASH eating
plan is the result of a pair of clinical research
studies and features a diet high in fruits, vegetables,
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 hypertension.
The DASH eating plan is appropriate for anyone
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 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.
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defibrillation A therapeutic method for delivering
an electrical shock to the HEART to restore it to
a functional rhythm. Defibrillation is an emergency
treatment necessary to prevent death
resulting from VENTRICULAR FIBRILLATION (rapid, discordant,
and ineffective contractions that fail to
pump BLOOD out 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 LONG QT 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 defibrillator
machine delivers the determined electrical
impulse, generally producing a pronounced jolt in
the person’s body. The desired effect is for all electrical
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 available.
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
BURNS to the person being resuscitated and electrical
shock or burns to the person administering
defibrillation. Burns may occur at the contact
points of the paddles or electrodes and also elsewhere
on the body where there are items of metal
such as jewelry or, in a hospital setting, monitoring
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 ventricular
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
BLOOD clots in the veins, usually the deep or inte-