Hyperthyroid heart disease is a condition that produces rapid changes in the functioning of the cardiovascular system as a result excessive thyroid hormone.

Hyperthyroidism commonly results in a hyperkinetic cardiovascular state shown by a fall in systemic vascular resistance, an increase in cardiac output, and enhanced left ventricular heart emptying. In pre-existing cardiac disease, thyrotoxicosis can worsen symptoms and induce cardiac decompensation. There is an increased association that exist between Graves' disease and mitral valve prolapse. Most individuals with cardiac problems due to hyperthyroidism are elderly and usually have toxic multinodular goiter.

Manifestations of the condition include: marked cardiovascular signs and symptoms; atrial fibrillation; occasionally congestive heart failure; and worsened angina pectoris. Signs and symptoms of hyperthyroid heart disease may occur as a result of thyrotoxicosis which may include: palpitations, tachycardia, and increased differences between systolic and diastolic blood pressures.

The functional abilities of cardiac patients can be classified in terms of metabolic equivalents (METs). The classification is generally as follows:

• Light to medium housework is 2 to 4 METs

• Heavy housework or yard work is approximately 5 to 6 METs

• Strenuous activity would be 7 to 10 METs, etc.

To determine the limitations on patient's functional abilities, the METs are considered in accordance with what symptoms are exhibited when the activities are carried out. For example, if a patient is performing activity at the 2 to 4 MET level and experiences dyspnea, fatigue, dizziness or fainting, the patient is considered to have low functional abilities.

Tests for the condition include: blood tests to determine thyroid hormone values and cardiac status; x-rays, and electrocardiogram (EKG).

Aggressive drug therapy is instituted to treat thyrotoxicosis to restore a euthyroid state promptly. Drug therapy may include propylthiouracil (PTU), beta blockers, and anticoagulant therapy. When fibrillation is present, cardioversion may be necessary if the normal sinus rhythm does not occur spontaneously when the person reaches the normal state of thyroid functioning.

Residual may vary from no residuals to a combination of signs and symptoms based on the status of thyroid activity and pre-existing cardiovascular disease.

• This disease shall be service-connected if it becomes manifest in a radiation-exposed Veteran as defined in paragraph (d)(3) of this section, provided the rebuttable presumption provisions of 38 CFR 3.307 of this part are also satisfied [38 CFR 3.309 [Disease subject to presumptive service connection], 38 CFR 3.309 (a) [chronic disease].

• Rate under the appropriate cardiovascular diagnostic code, depending on particular findings.

• For DCs 7009, 7010, 7011, and 7015, a single evaluation will be assigned under the diagnostic code that reflects the predominant disability picture.

Note

• Evaluate cor pulmonale, which is a form of secondary heart disease, as part of the pulmonary condition that causes it.

• One MET (metabolic equivalent) is the energy cost of standing quietly at rest and represents an oxygen uptake of 3.5 milliliters per kilogram of body weight per minute. When the level of METs at which breathlessness, fatigue, angina, dizziness, or syncope develops is required for evaluation, and a laboratory determination of METs by exercise testing cannot be done for medical reasons, a medical examiner may estimate the level of activity (expressed in METs and supported by specific examples, such as slow stair climbing or shoveling snow) that results in those symptoms.

• For this general formula, heart failure symptoms include, but are not limited to, breathlessness, fatigue, angina, dizziness, arrhythmia, palpitations, or syncope.

• The rating criteria for cardiovascular conditions underwent full-scale revision effective on November 14, 2021 and January 12, 1999.  A regulatory change was effective August 13, 1998, updated criteria for cold injury residuals under 38 CFR 4.104, DC 7122.  The changes are not considered liberalizing and should not be used as the basis for reduction unless the disability has actually improved.