Hypothyroid on cardiopulmonary bypass usage in children with congenital heart disease: A literature review

Congenital heart disease (CHD) is a birth defect that affects the structure or function of the heart. Cardiopulmonary bypass (CPB) is frequently used to treat CHD, which raises the risk of hypothyroidism. The disorder can cause circulatory problems, edema, and pleural effusion, all of which indicate heart failure. Hypothyroid conditions can cause decreased cardiac output due to poor relaxation of cardiac smooth muscle cells and reduced endothelial nitric oxide accessibility. This causes a chain reaction of increasing arterial stiffness, which raises systemic vascular resistance (SVR). Thyroid hormones also have an effect on the renin-angiotensin-aldosterone pathway, promoting the synthesis of renin substrates in the liver. This causes higher diastolic blood pressure, narrow pulse pressure, and decrease in renin levels in hypothyroid patients. Thyroid hormones also regulate the transcription of pacemaker genes, hence hypothyroid patients have a slower heartbeat. Hypothyroidism raises the likelihood of atrial fibrillation.