Cardiovascular manifestations of hypothyroidism

الملخص EN

Background : In hypothyroidism the heart muscle is weakened in both its contraction phase, and also its relaxation phase.

This means that the heart cannot pump as vigorously as it should, and the amount of blood it ejects with each heart beat is reduced.

In addition, because heart muscle does not relax normally in between heart beats, a potentially serious condition called diastolic dysfunction may result.

Aim : To evaluate the Prevalence of cardiovascular disorders in patients with primary hypothyroidism, and the relationship between these disorders and other factors like Age, Sex, BMI, and thyroid function status.

Methods : From January 2010 to April 2010, 43 patients were involved in the study, (39 females and 4 males), aging from 41 to 77 years.

They were known to have primary hypothyroidism and were randomly chosen from the attendants of the unit of endocrinology at Al-Kadhmyia Teaching Hospital-Baghdad.

They approved to participate by filling a questionnaire form involved age, sex, weight, first TSH reading, history of IHD, occurrence of hypertension, ECG, Arrhythmias, Chest X-ray, Echocardiogram, and lipid profile.

The collected data were statistically analyzed by using SPSS and Chi-square test to compare discrete variables.

Results and Discussion : Patients participated in the study were of age ranging from 41-77 years (mean 56) which indicates the occurrence of hypothyroidism in old age group.

They were 4 males and 39 females which suggests that hypothyroidism is a female disorder rather than of male.

The patients of the study were of body mass index ranging from 26-28 which refer to the overweight characteristic of the disease.

79.1 % of the patients were having mild elevation in TSH level (6.1-9.2Miu / L), and 20.9 % of them were having marked TSH elevation (10.4-12.8mIU / L).

Hypertension occurred in 44.2 % of patients, 68.4 % of them were of diastolic type due to that in hypothyroidism, the smooth muscles of the blood vessels are contracted forcing the heart to push the blood through smaller openings in the vessels resulting in raising the diastolic blood pressure.

Hypothyroidism can results in worsening of coronary artery disease, as 23.3 % of patients were having history of IHD.

By examining the ECG of patients involved in the study, 32.6 % of them showed atrial fibrillation as hypothyroidism prolongs the cardiac action potential resulting in ventricular irritability, premature beats and bradycardias.

Examination of Chest X-ray and Echocardiogram of patients of the study reveals that 30.2 % of them were having Cardiomegaly and pericardial effusion respectively due to increased capillary permeability, impaired lymphatic drainage and enhanced avidity for salt and water.

Lipid profile for all patients of the study showed elevation in the levels of total cholesterol and triglycerides over the normal ranges, and normal level of HDL.

Conclusion : Primary hypothyroidism occurred in old, overweighed females, and associated with cardiovascular manifestations which may be the only manifestations of thyroid dysfunction.