A Study of Cardiovascular Manifestations in Hypothyroidism

Abstract

Aim and Objective: To study cardiovascular manifestations in hypothyroidism. Materials and Methods: An observational study was carried out in Parul Sevashram Hospital, Vadodara, Gujarat, India. 150 patients, both men, and women, diagnosed with hypothyroidism attending the Parul Sevashram Hospital were recruited from the outpatient and in-patient departments of medicine. Clinical profiles, history, complications, and all required data were collected. All patients were regularly called for follow-up based on their visits. As per the investigator’s discretion, laboratory tests, i.e., thyroid function tests, CBC, electrocardiogram (ECG), and 2D echocardiography were performed as and when required, and medication was prescribed. All physical examinations and all vitals were recorded at every visit till the end of the study. Results: A total of 150 patients were included in this study. Male:female: 57:93; age: 28–76 years. Patients were examined in a prospective manner and results were compared with the control group to evaluate the effect of hypothyroidism, subclinical and overt, on the cardiac status by echocardiography. Variables of heart structure and function were assessed by cross-sectional and Doppler echocardiography. Interventricular septum (IVS) dimensions were significantly raised in moderate subclinical and severe overt hypothyroidism (mean 0.9 +/- 0.03 and 0.9 +/- 0.2 cm). Left ventricular posterior wall (LVPW) thickness was significantly increased only in overt hypothyroidism (mean 1.3 +/- 0.2). However, RVW and LVID showed no definite pattern of change. Pericardial effusion and diastolic dysfunction were seen in 72 cases only in overt hypothyroidism. Diastolic dysfunction with pericardial effusion was found in 74 (49.3%) cases followed by diastolic dysfunction in 49 (32.6%), systolic dysfunction in 15 (10.0 %), and increased interventricular septum spectrum thickness in 12 (8.6%) patients. The majority of the diastolic dysfunction was mild dysfunction associated with females. No cases were found to have severe diastolic dysfunction. Discussion: On the basis of a case history, the clinical and para-clinical manifestations of hypothyroidism are reviewed. Exertion dyspnea without signs of cardiac insufficiency occurs frequently. The minute and stroke volume and heart rate are reduced. The blood pressure may rise (reversible) and hypertension may occur. The function of the left ventricle is reversibly reduced. X-ray of the thorax may reveal massive relatively asymptomatic pleural effusion and cardiomegaly. Pericardial exudate occurs frequently and is demonstrated best by echocardiography. The plasma concentrations of several different enzymes (including creatine kinase (CK), CK-MB, and LDH) may be raised in myxedema. The reason for this is perhaps compromised membrane function in the skeletal muscle cells. Conclusion: Hypothyroidism, both subclinical and overt, is associated with cardiovascular alteration, both structural and functional. IVS and LVPW thickness are markedly affected, and there is an impairment in left ventricular function in diastole. Furthermore, hypothyroidism is more common in females, between the age group of 20–50 years. The majority of the patients have cardiovascular changes such as ECG abnormalities, pericardial effusion, diastolic dysfunction, and diastolic hypertension. We strongly suggest early detection and initiation of hormone replacement therapy can minimize the associated cardiovascular changes. Recommendation: To study inter-and intracellular deposits, infiltrations, and fibrosis in the myocardium and these probably contribute to some of the on-specific, reversible ECG changes (low voltage, flattening/inversion of T waves, sinus bradycardia). To study hypothyroidism present can increase atheroma formation. The patients can be grouped into overt and subclinical hypothyroid.