An ECG is useful for diagnosing heart
disorders, many of which produce devi-
ations from normal electrical patterns.
Electrodes connected to a recording
machine are placed on the chest, wrists,
and ankles. The machine displays the
electrical activity of the heart on a
screen or as a printed trace.
echinacheaA preparation of the plant
ECHINACEA ANGUSTIFOLIA, used in herbal
medicine. Echinachea is believed to
boost the immune systemand therefore
increase the body’s resistance to bacte-
rial, viral, and fungal infections.
echocardiographyA method of ob-
taining an image of the structure and
movement of the heart with ultrasound.
Echocardiography is a major diagnostic
technique used to detect structural, and
some functional, abnormalities of the
heart wall, heart chambers, heart valves,
and large coronary arteries. It is also
used to diagnose congenital heart dis-
ease (see heart disease, congenital),
cardiomyopathy, aneurysms, pericardi-
tis, and blood clots in the heart.
A transducer (an instrument that
sends out and receives sound signals)
is placed on the chest, or an ultrasound
probe is passed into the oesophagus
using a flexible endoscope. Ultrasound
waves are reflected differently by each
part of the heart, resulting in a complex
series of echoes, which are viewed on a
screen and can be recorded or the
results printed out. Developments such
as multiple moving transducers and
computer analysis give clear anatomical
pictures of the heart.
Doppler echocardiography measures
the velocity of blood flow through the
heart, allowing assessment of structural
abnormalities, such as septal defects.
echolaliaThe compulsive repetition of
what is spoken by another person. The
tone and accent of the speaker are
copied as well as the words. Echolalia
may be a symptom of schizophrenia and
sometimes occurs in people with a
learning disabilityor autism.
eclampsiaA rare, but serious condition
that develops in late pregnancy, during
labour, or after delivery. Eclampsia is
characterized by hypertension, protein-
uria, oedema, and the development of
seizures; it threatens the life of both the
mother and the baby. Eclampsia occurs
as a complication of moderate or severe
(but not mild) pre-eclampsia,
The warning symptoms of impending
eclampsia include headaches, confu-
sion, blurred or disturbed vision, and
abdominal pain. If untreated, seizures
can then occur and may be followed by
coma. Levels of blood plateletsmay fall
severely, resulting in bleeding; liver and
kidney function may be affected.
Careful monitoring of blood pressure
and proteinuria throughout pregnancy
ensures prompt treatment of impending
eclampsia. Immediate delivery, often by
caesarian section, together with antihy-
pertensiveand anticonvulsant drugsis
needed. Patients may need intensive
care to prevent the development of
complications such as kidney failure.
Blood pressure often returns to normal
in the months after delivery, but it may
remain high. There is a risk of recur-
rence in subsequent pregnancies.
econazoleAn antifungal drugused as a
cream for fungal skin infections (see
athlete’s foot; tinea), and in cream or
pessary form to treat vaginal candidia-
sis. Skin irritation is a rare side effect.
ECTThe abbreviation for electroconvul-
sive therapy, in which an electric current
is passed through the brain to induce
seizuresin order to treat severe depres-
sion. It is sometimes administered
under a short-lived general anaesthetic.
Temporary amnesiais a possible side
effect. ECT usually relieves depression
more rapidly than drug treatment and
may be lifesaving in severe depression
that is resistant to other treatments.
EcstasyAn illegal designer drug, rela-
ted to the amfetamine drugs. Ecstasy
has a mildly hallucinogenic effect and
generates feelings of euphoria. In most
people, the drug has no ill effects in the
short-term, but repeated use carries a
risk of liver damage. The most common
side-effect is hyperthermia. Taking the
drug causes intense thirst, and drinking
large quantities of water to combat this
may result in fatal damage to the body,
including brain swelling.
ectasiaA term meaning widening, usu-
ally used to refer to a disorder of a duct.ECHINACHEA ECTASIA
E