ECLAMPSIA
ELECTROCARDIOGRAPHY
Electrocardiography causes no
discomfort. Electrodes connected to
a recording machine are applied to the
chest, wrists, and ankles. The machine
displays the electrical activity in the
heart as a trace on a moving graph or
a screen. Any abnormality is thereby
revealed to the doctor, nurse, or
paramedic. Normal and abnormal
recordings are shown, below right.
An ECG can be taken at home, in the
doctor’s surgery, or in the hospital; a
recording lasting
24
hours or longer
can be obtained from a monitoring
device worn by the patient.
R
Normal ECG
This tracing shows the electrical activity
associated with one normal heartbeat. The
blue line shows the current flowing toward the
recording lead. The rise at P occurs just before
the atria (upper heart chambers) begin to
contract, the QRS “spike” occurs just before
the ventricles (lower chambers) begin to
contract, and the rise at T occurs as the
electrical potential returns to zero.
HOW ECG IS DONE
E C G m a c h i n e
T r a c e
A n k le e l e c t r o d e
Small electrodes,
connected by leads to
the recording machine,
are attached to the
chest, wrists, and
ankles using conducting
jelly or pads. Signals
from the electrodes
produce a trace.
T e c h n ic ia n
Normal rhythm
The heart chambers are
contracting regularly.
Ventricular fibrillation
Here, the contractions ofthe
lower heart chambers are
extremelyirregular.
Complete heart block
The upper and lower heart
chambers are beating
independently.
Atrial fibrillation
Here, the upper heart
chambers are beating fast and
irregularly, triggering irregular
contraction ofthe ventricles.
E
HOW IT IS DONE
Echocardiography is harmless and causes
no discomfort. A transducer (an instru-
ment that sends out and receives sound
signals) is placed on the patient’s chest,
or an ultrasound probe is passed into
the oesophagus using a flexible
endo-
scope
(viewing tube). Ultrasound waves
are reflected differently by each part of
the heart, resulting in a complex series
of echoes. These are viewed on a screen
and may be recorded, or the results can
be printed out.
DEVELOPMENTS
Developments such as multiple moving
transducers and computer analysis have
helped to provide clear anatomical pic-
tures of the heart.
Doppler echocardiography
is used to
measure the velocity (speed) of blood
flow through the heart. It allows for
the assessment of structural abnorm-
alities such as a
mitral valve prolapse
and
septal defects
.
echo-free
A term used in
ultrasound scanning
to
denote a structure that does not give rise
to reflections
(echoes)
of ultrasound
waves. A cyst filled with clear fluid, for
example, is echo-free.
echogenic
A term used in
ultrasound scanning
to
denote a structure that gives rise to
reflections (echoes) of ultrasound waves.
echolalia
The compulsive repetition of something
spoken by another person. The tone and
accent of the speaker are copied as well
as the words. Echolalia is sometimes seen
in
schizophrenia
and may occur in peo-
ple with
learning difficulties
or
autism
.
ECHO virus
The name for a specific group of RNA
viruses.
There are 3 2 types of ECHO
virus, and these cause a wide range of
conditions, including skin rashes, colds
(see
cold, common
) ,
gastrointestinal dis-
orders, and viral
meningitis
.
eclampsia
An uncommon but serious condition
that develops in a woman in late
preg-
nancy
,
during
childbirth
,
or after delivery.
Eclampsia is characterized by
hyperten-
sion
(high blood pressure),
proteinuria
(protein in the urine),
oedema
(accumu-
lation of fluid in body tissues), and the
development of
seizures
.
The condition
is life-threatening for both the mother
and the baby.
Eclampsia occurs as a complication
of moderate
or severe, although not
mild,
pre-eclampsia
.
SYMPTOMS
The warning symptoms of impending
eclampsia
include
headaches,
confu-
sion, blurred or disturbed vision, and
abdominal pain. If untreated, seizures
may occur and may be followed by
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