Heart Problems
This is one of the most serious complications of hyperthyroidism. These include a rapid heart rate, a heart rhythm disorder called atrial fibrillation that increases the risk of stroke, and congestive heart failure (a condition in which the heart can’t circulate enough blood to meet the amount body needs).
Thyroid hormone has an impact on the force and speed of human heartbeat, blood pressure, and cholesterol level. As a result, a malfunctioning thyroid gland can cause problems that disguise as heart disease or make existing heart disease worse. Hyperthyroidism leads to high cardiac output and left ventricular hypertrophy in the early stage, and biventricular dilatation and congestive heart failure in the late stage.