Cardiovascular Manifestations of Primary Hypothyroidism
Iraqi Postgraduate Medical Journal,
2010, Volume 9, Issue 2, Pages 113-119
Primary hypothyroidism accounts for 90 to 95 %of all cases of hypothyroidism. Thyroid hormone deficiency increases systemic vascular resistance, decreases contractility and slow the heart rate .
OBJECTIVE: To investigate cardiac changes in primary hypothyroidism.
In this prospective study 36 patients with untreated primary hypothyroidism were compared with 30 healthy persons. Cardiovascular evaluation of all subjects had been made both clinically and by the following studies :Chest X-Ray, electrocardiography, serum lipid and Echocardiography.
The main cardiac manifestations of hypothyroidism were: Easy fatigability( 88.9 %(, exertional dyspnea )75%o),obesity or gaining weight( 66.7 %(, sinus bradycardia ) 47.2 %(and peripheral edema(11.1 %(Electrocardiography showed sinus bradycardia in( 47%( low QRS voltage in )33.3%( , flat or inverted T wave(27.8%), prolonged QT interval )19.5%), first degree heart block in( 19.5 %(
.Echocardiography showed the following :a decrease in global systolic function, asymmetric sepal
hypertrophy in )91.6%) Pericardial effusion in )38.8%).Low QRS voltage was found to be related to thyroxin level and age of the patient .No correlation was found between heart rate and thyroxin level.
Primary hypothyroidism accompanied by significant changes in cardiovascular system which may explain the development of premature coronary artery disease in these patients.
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