Cardiomyopathy is a disease in which the myocardium has become damaged or defective. Although there are four forms of cardiomyopathy accounted for (dilated, hypertrophic, restrictive and obliterative), the obliterative form is rarely encountered in the United States.

Etiologic factors related to the three common forms of cardiomyopathy are as follows:

• Dilated - This form is associated with excessive drinking of alcohol, chemotherapy for cancer, viral infections, acquired immunodeficiency syndrome (AIDS) infection, recurrent myocardial infarction (MI), and unknown factors.

• Hypertrophic - In this form, the myocardium is thickened. This form is also hereditary in over 50% of cases, or there are unknown factors.

• Restrictive - In this form, the muscle is infiltrated with disease such as amyloidosis, hemachromatosis, and glycogen storage disease, or the cause is unknown.

Manifestations of the common forms of cardiomyopathy are as follows:

• Dilated - This form is characterized by dyspnea and fatigue; arrhythmias that may cause fainting; palpitations; and thrombi on the walls of the heart chambers with systemic and pulmonary emboli. Examination may reveal a rapid heart rate, neck vein distention, rales, and edema. Chest pain may also be present.

• Hypertrophic - This form is characterized by angina from exertion; fainting; dyspnea on exertion; heart arrthythmias; and symptoms imitative of coronary artery disease or aortic stenosis. Signs of increased venous pressure (ascites, jugular vein distention, ankle edema, and pleural effusion) do not appear until the later stages of the disease.

• Restrictive - This form is characterized by rigidity of the heart muscle, and manifestations of congestive heart failure (CHF). An enlarged liver, peripheral edema and ascites are evident. Due to pulmonary venous hypertension, there is dyspnea with exertion, and orthopnea. Limitations on effort are a consequence of improper filling of the ventricles. 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 2-4 MET level and experiences labored or difficulty breathing (dyspnea), fatigue, dizziness or fainting, the patient is considered to have low functional abilities.

Diagnostic tests for all forms of cardiomyopathy include: chest x-ray, electrocardiogram (EKG), echocardiography, radionuclide imaging, and cardiac catheterization. In restrictive cardiomyopathy, a myocardial biopsy may be included.

Treatment of the three forms of the condition is as follows:

• Dilated - The underlying toxins (alcohol, etc.) need to be removed or chemotherapy should be instituted as soon as possible and any disease process corrected (e.g., beriberi). Use of ACE inhibitors have improved the prognosis along with salt restrictions, digitalis, and diuretics. Due to the presence of mural (on the heart wall) thrombi, the use of oral anticoagulants will help prevent emboli. Implantation of a permanent pacemaker is a possibility if the patient goes into heart block. Some patients have shown significant improvement after coronary bypass surgery and, for patients younger than 60 with a poor prognosis, a heart transplant is a viable option.

• Hypertrophic - Medications (beta-blockers or calcium channel blockers or both) are used initially as the cornerstone of treatment. The use of nitroglycerin for angina is contraindicated, and diuretics are used cautiously. Bacterial endocarditis may occur, and antibiotics must be prescribed for dental work or surgery. The major challenge is the prevention of sudden cardiac death at a young age. Patients with this disease should not engage in competitive sports. For patients not controlled by medical measures, some surgeries are available. By using a cardiopulmonary bypass, the obstruction of the left ventricle outflow is removed (myotomy-myectomy). The 10-year survival rate for this procedure is better than 85%. This surgery does relieve symptoms, but it does not remove the threat of sudden cardiac death.

• Restrictive - There is no specific therapy for this disorder. Death is from arrthymias or CHF. Those who have cardiomyopathy from hemochromatosis improve when excess iron is removed by phlebotomy. Those with amyloidosis show limited response to treatment with steroids.

Sudden death is frequent in all the cardiomyopathies, but it is most common in the hypertrophic form at a young age. Progressive CHF is the cause of death in 75% of patients. After onset of symptoms, most deaths will occur within 5 years.

• May be entitled to special monthly compensation where the Veteran has a single service-connected disability rated as 100% with additional service-connected disability or disabilities independently ratable at 60% or more, which are separate and distinct from the 100% service-connected disability and involves different anatomical segments or bodily systems. See  38 CFR 3.350(i)(1) – Special Monthly Compensation (SMC).

Notes

• 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.