Abstract

ABSTRACT:
BACKGROUND:
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.
METHODS:
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.
RESULTS::
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.
CONCLUSION:
Primary hypothyroidism accompanied by significant changes in cardiovascular system which may explain the development of premature coronary artery disease in these patients.