Can Chronic releases of excess thyroxine cause a sustained increase in the heart and weakened heart?
Chronic releases of excess thyroxine can cause a sustained increase in the heart rate and result in a weakened heart. This condition is known as thyrotoxicosis or hyperthyroidism. Here's how it occurs:
1. Increased Metabolic rate: Excess thyroxine hormone increases the body's metabolic rate, which means the body burns energy faster. This causes the body to work harder and puts strain on various systems, including the cardiovascular system.
2. Increased Heart rate: The increased metabolic rate requires more oxygen and nutrients to be delivered to the body's tissues. The heart rate increases as a compensatory mechanism to meet this demand. This sustained increase in heart rate is called tachycardia.
3. Cardiac Hypertrophy: Over time, the heart muscles undergo changes known as cardiac hypertrophy. This means the heart muscle cells enlarge to meet the increased workload caused by the higher heart rate. While cardiac hypertrophy can initially help the heart adapt to increased demands, sustained hypertrophy can weaken the heart muscle and lead to complications.
4. Atrial Fibrillation: Chronic thyrotoxicosis can cause the heart's upper chambers (atria) to develop an abnormal heart rhythm called atrial fibrillation. Atrial fibrillation causes rapid and irregular heartbeats, reducing the heart's efficiency in pumpings blood effectively.
5. Heart Failure: Prolonged thyrotoxicosis can lead to heart failure. When the heart muscle is overworked for an extended period, it can eventually become weakened and unable to pump blood effectively. This can lead to symptoms such as shortness of breath, fatigue, and swelling in the legs.
It's important to note that chronic releases of excess thyroxine are usually caused by underlying thyroid conditions such as Graves' disease or toxic nodular goiter. Early diagnosis and treatment of the thyroid disorder are crucial to prevent or manage the adverse effects of thyrotoxicosis on the heart.