Page 190 - fbkCardioDiabetes_2017

166 Cardiomegaly in Diabetes Mellitus

triglycerides). These predispose to more chances of CLINICAL FEATURES
cardiac hypertrophy and thereby to heart failure and Prominent ‘a’ wave in JVP or a sustained cardi-
stroke. Women are also easily predisposed to hypo- ac apical impulse is an early clinical finding. After
glycaemic events.
the development of systolic dysfunction in the later
Women have some unique risk profiles such as hy- stages, associated with left ventricular dilatation and
pooestrogenemia and protracted dysmetabolic state symptomatic heart failure, JVP may become elevated
which may promote an inflammatory milieu. Inflam- and apical impulse would become displaced down
matory factors disturb insulin action and interact with and left. Systolic murmur might be heard in the mitral
female sex hormones. area. ECG changes occur in 60% of the patients and
QT prolongation occurring in later stages is indicative
Insulin resistance which is higher in women, stimu- of fibrosis.
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lates increase in left ventricular mass . Framingham
study shows insulin resistance to be significantly CARDIOMEGALY IN INFANTS OF DIABETIC
more related to left ventricular mass in women than
in men. Trophic stimulating effect of insulin resis- MOTHERS
tance, causes increase in wall thickness and thereby Congenital cardiac defects predominate in infants
the ventricular dimension. born to diabetic mothers. They include cardiovascular
maladaptation to extrauterine life, congenital heart
Obesity is commoner in women with diabetes, mak-
ing their left ventricles prone for concentric hypertro- defects and hypertrophic septal cardiomyopathy.
phy. This explains the higher incidence of diastolic The incidence of foetal cardiac malformations is the
dysfunction, which is comparatively more severe in highest in mothers who are on insulin at the time of
women. conception.
Symptomatic hypertrophic cardiomyopathy occurs
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Moreover, women are relatively undertreated com- in12.1% of these infants, but when routinely searched
pared to men.
with ECHO , it is found to be 30%. The left ventricular
According to Framingham study, cardiovascular risk mass and contractility are increased and there is left
develops in a female at least 15 years before a clinical ventricular outlet tract obstruction. Cardiac output is
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diagnosis of diabetes . significantly reduced secondary to decreased stroke
volume and is directly related to the degree of septal
DIABETIC CARDIOMYOPATHY (DCM) hypertrophy.
The incidence of diabetic cardiomyopathy is being Foetal hyperinsulinaemia triggered by maternal hy-
recognized as not only due to the metabolic and perglycaemia during the third trimester causes the
functional changes, but to the structural changes asymmetric septal hypertrophy. Foetal cardiac septal
also. hypertrophy correlates with maternal HbA1c levels.
Leading causes of heart failure in diabetes are due The severity of cardiomyopathy in these infants, can
to coronary artery disease (CAD) and diabetic car- vary from an incidental finding on ECHO (30%cases),
diomyopathy. But the cardiomyopathy is recognised to congestive cardiac failure (1.2)% cases.
only in the absence of CAD.
This cardiomyopathy is usually benign, producing
DCM is characterised by enlargement of cardiac a systolic murmur and transitory cardiomegaly. All
cells, ventricular enlargement, prominent interstitial symptoms usually regress spontaneously within a
fibrosis and decreased or preserved systolic function, few weeks. Rarely, overt congestive cardiac failure
in the presence of diastolic dysfunction. may develop with tachypnoea, tachycardia, gallop
One peculiarity of DCM is the long latent phase, rhythm and hepatomegaly. Hence, supportive care
during which the disease progresses, but is com- with fluid restriction, diuretics and oxygen are all that
pletely asymptomatic . is necessary.
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One of the earliest signs is mild left ventricular di- The natural history of hypertrophic cardiomyopathy
astolic dysfunction, with little effect on ventricular in the infants is benign and the symptoms resolve in
filling. 2 to 4 weeks and septal hypertrophy resolves in the
first 2 to 12 months of life, irrespective of treatment.
Hence a detailed ECHO needs to be done in all dia-
betic women with pregnancy.

GCDC 2017