Book of Medical Disorders in Pregnancy - Tintash

differentiate from hemodynamically
significant murmurs if the patient has not
been examined before. If the murmur is
loud and transmitted to the axilla or neck
vessels, and its association with a
palpable thrill is established, it is
abnormal without exception. It is conventional
to grade murmurs according to
their intensity. The grades vary from one
to six. The grade I murmur can be heard
with special effort only. The grade II
murmur is very faint but is recognizable
with some experience. The grade III
murmur is prominent but is not so loud;
a grade IV murmur is much louder. The
grade V murmur is also loud while the
grade VI murmur is the loudest and can
even be heard with stethoscope while it
is barely in contact with the chest wall.
In the absence of heart disease a
pregnant patient should have no murmur
louder than grade II. Blood flow
murmurs associated with pregnancy are
heard along the left sternal border in
nearly 90 per cent of pregnant women.
They do not usually radiate to the axilla,
and are not associated with thrills of any
sort. The diastolic murmur of aortic
regurgitation is usually faint and some
times, inaudible during pregnancy. This
murmur is heard while the patient is
squatting or performing strenuous work.
Diastolic cardiac murmurs in pregnancy
always indicate cardiac pathology. A
diastolic bruit originating in the internal
mammary artery may be misinterpreted
as being cardiac in origin.
A murmur which originates from the
breast vasculature can be heard in about
10 per cent pregnant women, during the
third trimester.
Heart sounds and murmurs - A
parasternal systolic murmur is heard in
most cases and is due to increase in
75
blood volume which occurs in normal
pregnancy.
This is the murmur of organic mitral
regurgitation and careful interpretation is
necessary since the presence of an S3
gallop signifies left ventricular failure.
More than 80 per cent of women
develop a third heart sound at some time
during pregnancy.
The frequency parallels the increase in
cardiac output. Systolic murmurs
increase in intensity during pregnancy.
This is due to increased blood flow
across normal cardiovascular valve s.
This is particularly so in murmurs
arising in the pulmonic and aortic areas.
Systolic murmurs produced by mitral
regurgitation usually become softer
during pregnancy, because systemic
arterial resistance falls.
Murmur in mitral valve prolapse
syndrome:
In this syndrome an apical systolic
murmur is noted and is preceded by a
mid systolic click. The majority of
patients with a mitral valve prolapse
syndrome have uneventful gestation.
These patients are susceptible to subacute
bacterial endocarditis and should
be protected with antibiotics at delivery.
Chest X-ray:
A chest X-ray is useful to assess the
degree of enlargement of the heart.
Similarly, enlargement of a particular
chamber of the heart can be detected and
the presence of pulmonary over
circulation diagnosed. It is wise not to
expose the fetus to radiation, unless it is
absolutely necessary.