Secondary and Infiltrative Cardiomyopathies

Secondary and infiltrative cardiomyopathies are the least common forms of cardiomyopathy and often are the most difficult to treat. In all cases, efforts should be made to establish a specific diagnosis because the removal or avoidance of the causative agent (eg, alcohol, cocaine, persistent tachycardia) holds the best promise for reversal of ventricular dysfunction. Patients who present with a dilated cardiomyopathy (DCM) should be treated with standard heart failure therapy. However, the "standard" is changing and clinicians need to take heed of results of recent trials establishing the role of beta-blockers, aldosterone, and angiotensin receptor antagonists in addition to the regimen of digoxin, diuretics and angiotensin-converting enzyme (ACE) inhibitors. In contrast, patients who present with a more infiltrative clinical picture often manifest more diastolic dysfunction and need strict volume control to maintain euvolemia. For patients with biopsy-proven myocarditis, immunosuppressive therapy generally should be considered in an effort to maintain and potentially improve ventricular function. Patients with sarcoid heart disease have shown the greatest response to high-dose corticosteroids. Patients with hemochromatosis related cardiomyopathy should be treated with iron chelation therapy and phlebotomy. The role of cardiac transplantation is limited, as most of the secondary and infiltrative causes of cardiomyopathy are associated with an adverse posttransplant outcome. Other surgical options, such as left ventricular assist devices, may offer hope to patients who would otherwise be ineligible for cardiac transplantation. On the horizon, biventricular pacing and treatments targeted at cytokines and hormonal receptors hold the promise of improving symptoms and prolonging survival by counteracting the deleterious effects of these secondary mediators.