How is high output heart failure in hyperthyroidism managed?

From the Guidelines

High output heart failure in hyperthyroidism is best managed by treating the underlying thyroid dysfunction and cardiac manifestations, with a primary approach of achieving euthyroidism through antithyroid medications and beta-blockers to control tachycardia and reduce cardiac workload. The management of high output heart failure in hyperthyroidism involves a multifaceted approach that addresses both the thyroid dysfunction and the cardiac manifestations.

Key Considerations

• Achieving euthyroidism is crucial and can be done through antithyroid medications such as methimazole (starting at 10-30 mg daily) or propylthiouracil (100-300 mg three times daily) 1.
• Beta-blockers, particularly cardioselective ones like metoprolol (25-100 mg twice daily) or non-selective propranolol (10-40 mg three to four times daily), are essential to control tachycardia and reduce cardiac workload 1.
• Diuretics such as furosemide (20-80 mg daily) may be needed to manage fluid overload and reduce preload, with the goal of establishing optimal volume status 1.
• Standard heart failure medications including ACE inhibitors or ARBs may be added if needed, though with caution as hyperthyroid patients often have low systemic vascular resistance 1.

Treatment Approach

The treatment approach should be guided by the principles of managing heart failure, including the assessment and management of precipitating factors, comorbidities, and previous limitations to ongoing disease management related to social determinants of health 1.

• Definitive treatment of hyperthyroidism through radioactive iodine therapy or thyroidectomy should be considered once the patient is stabilized.
• Close monitoring of thyroid function, heart rate, blood pressure, and fluid status is crucial during treatment 1.

Pathophysiology

The management works by addressing the pathophysiology where excess thyroid hormone increases cardiac contractility, heart rate, and blood volume while decreasing systemic vascular resistance, all of which contribute to the high-output state that can eventually lead to cardiac failure if left untreated 1.

Recent Guidelines

Recent guidelines emphasize the importance of optimal medical therapy, including the use of diuretics, ACE inhibitors or ARBs, and beta-blockers, in the management of heart failure 1.

• The 2022 AHA/ACC/HFSA guideline for the management of heart failure highlights the need for a comprehensive approach to management, including the assessment and management of precipitating factors, comorbidities, and previous limitations to ongoing disease management related to social determinants of health 1.

From the Research

High Output Heart Failure in Hyperthyroidism

• High output heart failure in hyperthyroidism is characterized by an increase in resting heart rate, blood volume, stroke volume, myocardial contractility, and ejection fraction 2.
• The development of high output heart failure in hyperthyroidism may be due to tachycardia-mediated cardiomyopathy 2.
• Hyperthyroidism can cause cardiac arrhythmias, heart failure, osteoporosis, and adverse pregnancy outcomes if left untreated 3.

Management of High Output Heart Failure in Hyperthyroidism

• The primary treatment for hyperthyroidism includes antithyroid medications (methimazole and propylthiouracil), radioactive iodine ablation of the thyroid gland, or surgical thyroidectomy 4.
• Treatment options for overt hyperthyroidism from autonomous thyroid nodules or Graves disease include antithyroid drugs, radioactive iodine ablation, and surgery 3.
• Conventional therapies for heart failure, such as angiotensin converting enzyme inhibitors, angiotensin receptor blockers, and certain beta-blockers with vasodilatory properties, may not be effective in high output heart failure and could potentially worsen the condition 5.
• Therapeutic options for high output heart failure are limited, but may include dietary restriction of salt and water combined with judicious use of diuretics 5.

Treatment of Hyperthyroidism

• Methimazole (MMI) and propylthiouracil (PTU) are the main antithyroid drugs used for hyperthyroidism, with MMI being the drug of choice due to its widespread availability, longer half-life, and small number of severe side effects 6.
• Other treatment options for hyperthyroidism include potassium perchlorate, beta blockers, iodine, lithium carbonate, and glucocorticoids 6.
• Rituximab, a monoclonal antibody directed against human CD20, has been proposed as a biological therapy for cases of Graves' disease unresponsive to traditional drugs 6.