Harvard Health Letter

Thyroid disorders and heart conditions: What’s the connection?

Thyroid disorders are often overlooked as the cause of heart problems. An underactive thyroid may cause blood pressure problems, a slow heart rate, an increase in cholesterol, an increase in fluid around the heart, and heart failure. An overactive thyroid can cause the heart to beat faster, which can lead to palpitations or an irregular heartbeat known as atrial fibrillation (afib). Treating the thyroid may help relieve symptoms and may reverse some heart conditions. However, it’s very difficult to reverse afib in someone with ongoing hyperthyroidism. 
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