- Dilated cardiomyopathy is a disease of heart muscle characterized by dilation of the cardiac chambers and reduction in ventricular contractile function.
- Lifetime incidence of 36.5 cases per 100,000 persons
- Approximately 10,000 U.S. deaths annually
- Dilated cardiomyopathy may be secondary to progression of any process that affects the myocardium and dilation is directly related to neurohormonal activation. The majority of cases are idiopathic.
- Dilation of the cardiac chambers and varying degrees of hypertrophy are anatomic hallmarks. Tricuspid and MR are common due to the effect of chamber dilation on the valvular apparatus.
- Atrial and ventricular arrhythmias are present in as many as one-half of these patients and probably are responsible for the high incidence of sudden death in this population.
- Symptomatic heart failure (dyspnea, volume overload) is often present.
- A portion of patients with preclinical disease may be asymptomatic.
- The ECG is usually abnormal, but changes are typically nonspecific.
Imaging and Diagnostic Studies
- The diagnosis of dilated cardiomyopathy can be confirmed with echocardiography or radionuclide ventriculography.
- Two-dimensional and Doppler echocardiography is helpful in differentiating this condition from hypertrophic or restrictive cardiomyopathy, pericardial disease, and valvular disorders.
- Endomyocardial biopsy provides little information that affects treatment of patients with dilated cardiomyopathies and is not routinely recommended.
- The medical management of symptomatic patients is identical to that for HF from other causes.
- Therapeutic strategies include control of total body sodium and volume in addition to appropriate preload and afterload reduction using vasodilator therapy.
- Î²-Adrenergic antagonists should be used unless contraindicated.
- Immunizations against influenza and pneumococcal pneumonia are recommended.
- Chronic oral anticoagulation has not been shown to decrease the risk of thromboembolism in patients with LV dysfunction. Anticoagulation should be strongly considered in individuals with a history of thromboembolic events, atrial fibrillation, or evidence of an LV thrombus. The level of anticoagulation recommended varies but is generally an international normalized ratio of 2.0-3.0.
- Immunosuppressive therapy with agents such as prednisone, azathioprine, and cyclosporine for biopsy-proven myocarditis has been advocated by some, but efficacy has not been established.
- Dilated cardiomyopathy (of nonischemic origin) is associated with an increased incidence of sudden cardiac death (SCD) and ventricular arrhythmia. When compared to NYHA Class IV HF patients, who are more likely to die of progressive pump failure, sudden cardiac death is relatively more common in patients with mild to moderate symptoms.
- Suppression of asymptomatic ventricular premature beats or nonsustained ventricular tachycardia (NSVT) using antiarrhythmic drugs in patients with HF does not improve survival and may increase mortality as a result of the proarrhythmic effects of the drugs.
- Primary prevention of SCD is recommended by implantation of an implantable cardioverter-defibrillator (ICD) in patients with dilated cardiomyopathy, an ejection fraction of 35% or less, and NYHA class IIâ??III symptoms. Patients should receive aggressive medical treatment including neurohormonal blockade, correction of electrolyte imbalances, and discontinuation of proarrhythmic drugs.
- Medical therapy is recommended for 3 months following a new diagnosis of dilated cardiomyopathy (DCM) prior to ICD implantation for primary prevention.
- Cardiac resynchronization therapy may be beneficial in selected patients with symptomatic HF.
- Cardiac transplantation should be considered for selected patients with HF that is refractory to medical therapy.
- Intra-aortic balloon counterpulsation or placement of a ventricular assist device may be necessary for stabilization of patients in whom cardiac transplantation is an option or before other definitive surgical therapies.
- Mitral valve annuloplasty or replacement can be used for symptomatic relief in patients with severe MR.