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Cardio Diabetes Medicine 2017 165

Cardiomegaly

in Diabetes Mellitus

Dr. T. Geetha, MD.,

Associate Professor of Medicine
Government Medical College and ESI Hospital, Coimbatore

INTRODUCTION : CARDIOMEGALY IN DIABETES
Diabetes is now regarded as the strongest risk factor Cardiomegaly is a well recognized condition in di-
for heart disease. The heart disease is not solely due abetes. The metabolic changes induce hypertrophy
to blood glucose levels. The blood vessels in these of the cardiac cells. This, combined with other risk
patients are more susceptible to well established fac- factors like obesity, hypertension, increasing age,
tors like smoking, high cholesterol levels and high lipid dysfunction and the use of thiazolidinediones
blood pressure. All these lead to accelerated athero- can accentuate the process of cardiomegaly. This
sclerosis. This in turn causes increase in cardiovas- results in the well recognized entity called Diabetic
cular mortality and heart failure. Epidemiological and Cardiomyopathy.
clinical data now indicate that diabetes increases the Female gender has a special predilection for cardio-
risk for cardiac dysfunction by structural, functional megaly. Thiazolidinediones can cause adipose tissue
and metabolic changes. Left ventricular hypertrophy accumulation and myocardial hypertrophy.
is an ongoing process which may not be recognised
early. A lesser known entity is the role of erythrocyte rhe-
ology in the development of cardiac hypertrophy. Re-
THE HEART IN DIABETES MELLITUS : search using animal models has tried to explore this
relationship. Rheological changes include reduced
Heart failure is a very common presentation in the
diabetic. Early progression to heart failure after an red cell filtration and increased red cell aggregation.
acute myocardial infarction is more frequent in di- Decreased coronary reserve in diabetes mellitus can
abetics than in non diabetics. While atherosclerosis result in rheological changes leading to left ventric-
and ular hypertrophy.
Increased intracellular magnesium is also attributed
ischaemic injury are important contributing factors to to the development of cardiac hypertrophy.
the high incidence of heart failure, another important
factor is diabetes induced changes within the heart
itself. A prominent change which occurs is a switch DIABETES, CARDIOMEGALY AND FEMALE
in the cardiac energy metabolism. Increase in fatty GENDER
acid oxidation accompanied by decrease in glucose Cardiovascular disease is the leading cause of death
metabolism , can result in the myocardium becoming in women, globally. Women with Type 2 diabetes are
1
entirely reliant on fatty acid oxidation as a source of at even more higher risk than non diabetic women
energy. The change in energy metabolism and the re- and diabetic men . There are considerable sex differ-
2
sultant increase in advanced glycosylation products ences in the occurrence of various manifestations of
increases the susceptibility of the heart to both isch- cardiovascular disease.
aemic injury and contractile dysfunction, both systol-
ic and diastolic. Evidence also reveals that patients Diabetic women have higher levels of endothelial
with diabetes have increased levels of low grade in- dysfunction, higher prevalence of abdominal obesi-
flammation in their arterial lining, which becomes a ty, abnormalities in fibrinolysis and thrombosis path-
forerunner for cardiac disease. ways and abnormalities in lipids (low HDL and high

Cardio Diabetes Medicine