Bma Illustrated Medical Dictionary

is small and closes without treatment.

Surgery may be performed for larger

defects, usually with good results.

ventricular tachycardiaA serious car-

diac arrhythmiain which each heartbeat

is initiated from electrical activity in the

ventriclesrather than from the sinoatrial

nodein the right atrium. It is caused by

an abnormally fast heart-rate due to

serious heart disease, such as myocar-

dial infarctionor cardiomyopathy. It may

last for a few seconds or for several

days. Diagnosis is confirmed by ECG.

Emergency treatment is with defibril-

lationand an antiarrhythmic drug.

verapamilA drug that acts as a calcium

channel blocker to treat hypertension,

angina pectoris, and certain arrhythmias.

Possible side effects include headache,

flushing, dizziness, and ankle swelling.

vernixThe white, cheese-like substance

covering a newborn baby. Vernix com-

prises fatty secretions and dead cells. It

protects the skin, insulates against heat

loss before birth, and lubricates the

baby’s passage down the birth canal.

verrucaThe Latin name for a wart, com-

monly applied to warts on the soles.

versionA change in the direction in

which a fetuslies so that a malpresenta-

tion, most often a breech (bottom-down)

presentation, replaces the normal head-

down presentation.

vertebraAny of the 33 approximately

cylindrical bones that form the spine.

There are 7 vertebrae in the cervical

VENTRICULAR SEPTAL DEFECT

between the air in the lungs and the

blood. Ventilatory failure may be due to

brain damage or to depression of the

respiratory centres by excessive doses of

drugs such as morphine. Treatment may

involve artificial ventilationor, in some

cases, the use of respiratory stimulant

drugs. (See also respiratory failure.)

ventouseSee vacuum extraction.

ventralRelating to the front of the

body, or describing the lowermost part

of a body structure when a person is

lying face-down. The opposite is dorsal.

ventricleA cavity or chamber. Both the

heartand brainhave anatomical parts

known as ventricles.

The brain has 4 ventricles: 1 in each of

the 2 cerebral hemispheres; a 3rd at the

centre of the brain, above the brain-

stem; and a 4th between the brainstem

and cerebellum. These cavities are filled

with cerebrospinal fluid.

The ventricles of the heart are its 2

lower chambers, which receive blood

from each atriumand pump it to the

lungs and to the rest of the body.

ventricular ectopic beatA type of

cardiac arrhythmiain which abnormal

heartbeats are initiated from electrical

impulses in the ventriclesof the heart.

In a normal heart, beats are initiated by

the sinoatrial nodein the right atrium.

Ventricular ectopic beats may be de-

tected on an ECG. If there are frequent

abnormal beats that cause symptoms,

or beats that arise from more than 1

site in the ventricles, treatment with an

antiarrhythmic drugmay be required.

ventricular fibrillationOne of the 2

life-threatening cardiac arrhythmiasthat

occur in cardiac arrest. The hearthas

rapid, uncoordinated, ineffective con-

tractions and does not pump blood. The

problem is due to abnormal heartbeats

initiated by electrical activity in the ven-

tricles. It is a common complication of

myocardial infarctionand may also be

caused by electrocution or drowning.

The diagnosis is confirmed by ECG.

Emergency treatment is with defibrilla-

tionand antiarrhythmic drugs.

ventricular septal defectThe medical

term meaning a hole between the lower

2 chambers of the heart. The abnormality

is present from birth and in many cases

VENTOUSE VERTEBRA

V

Ventricular septal

defect

Right

ventricle

of heart

Septum

Left

ventricle

of heart