Pediatric Dilated Cardiomyopathy Treatment & Management

Initial therapy in dilated cardiomyopathy (DCM) is largely directed at the symptoms of the underlying heart failure. Diuretics, angiotensin-converting enzyme (ACE) inhibitors, and beta-blockers are used.

Perform general supportive measures in patients with DCM during acute-stage management, including endotracheal intubation and mechanical ventilation, vasoactive infusions, and fluid/acid-base management. Treat chest infections appropriately. Treat anemia appropriately.

Supplemental oxygen is of benefit only in patients with hypoxia (as with pneumonia or pulmonary edema).

Cardiac transplantation is currently the optimal treatment for DCM-induced resistant chronic heart failure in children. Limiting factors include availability of a suitable donor, complications of rejection, and lifelong immunosuppression. Survival rates of as much as 92% at 5 years^[27] and 53% at 15 years have been reported.^[28] A variety of other surgical procedures have been studied.

Diuretics, ACE inhibitors, and beta-blockers form the pharmacologic regimen for heart failure in DCM. Diuretics may provide an improvement in symptoms, whereas ACE inhibitors appear to prolong survival.

Beta-blocker therapy in children with chronic heart failure due to DCM has been shown to improve symptoms and left ventricular ejection fraction. Carvedilol is a beta-adrenergic blocker with additional vasodilating action. Carvedilol, in addition to standard therapy for dilated cardiomyopathy in children, is believed to improve cardiac function and symptoms; it is well tolerated, with minimal adverse effects, but close monitoring is necessary because it might worsen congestive heart failure and precipitate asthma. Furthermore, randomized control studies have not yet documented the beneficial effects of carvedilol, although it is not clear whether these studies were large enough to bring out the differences.^[30]

Anticoagulants and antiarrhythmic agents, particularly amiodarone, are often used in patients with low myocardial contractility and symptomatic arrhythmias, respectively. Results are encouraging. Presence of intracardiac thrombi, symptomatic or not, is another indication for anticoagulant therapy.^[31]

Carnitine supplements (100 mg/kg IV infusion over 30 min, followed by 100 mg/kg/day as continuous infusion for 24-72 hours; 25-50 mg/kg/dose PO bid or tid, not to exceed 200 mg/kg/day) reverse the myocardial dysfunction in most patients affected by systemic carnitine deficiency.

Investigational drug therapy

Coenzyme Q10 has also been used in children with DCM, with variable results.^[32]

Decreased serum levels of growth hormone (GH), which acts on cardiac myocytes primarily through insulinlike growth factor (IGF)-1, are associated with impaired myocardial growth and function, which can be improved with the restoration of GH/IGF-1 homeostasis. Based on this hypothesis and on observation of benefits in animal models, GH therapy has been used in children with DCM, but the results have not been conclusive.

Palliative surgical measures are associated with significant mortality and morbidity rates despite advances. Resection of a large segment of the hypertrophied ventricular muscle (Batista procedure) and repair or replacement of mitral valve to minimize volume overload of left ventricle have been used as palliative measures. Cardiomyoplasty is the transposition of electrically transformed skeletal muscle to provide systolic and diastolic augmentation to the native heart.

Mitral valve repair and partial left ventriculectomy have been found to be feasible in selected patients and help reduce symptoms in most patients and help^[33] reduce left ventricular dimensions in some patients; however, whether it can modify the natural history, especially the need for cardiac transplantation, is unclear.^[34]

Implantable mechanical support devices, modified for use in infants and children, have been introduced to support the failing heart until a suitable donor is available for transplantation (bridge to transplant). The Berlin Heart EXOR pediatric has also been successfully used in several centers.^[35] Major limitations include infection, thromboembolism, disturbance from noise, and the need to frequently recharge batteries.

Cardiac resynchronization therapy using a biventricular pacemaker has been shown to be effective in adults with DCM. In addition, these devices are available with defibrillator backup for patients at risk for ventricular arrhythmias. They are used in children with DCM with early favorable results.^[36]

In adult studies, some patients receiving prolonged support of left ventricular function with these devices have shown restoration of native cardiac function. In a few cases, myocardial recovery has been sufficient to permit successful removal of the left ventricular assist system, even after a year of use. This suggests a possible role for mechanical intervention at an earlier stage in viral myocarditis and DCM. A lesser degree of fibrotic changes in the left ventricle could improve the chances of recovery.

Stem cells, particularly cardiac stem cells, and cardiac progenitor cells may represent promising types of cellular therapy to replace dead myocardial cells, but the technology is presently a research topic rather than a clinical option.^{[37, 38]}

Admission is necessitated for patients with DCM who have exacerbations of heart failure; often these are precipitated by chest infection. Admission may also be necessary for reevaluation if first-line medications fail to provide significant relief of symptoms (ie, resistant heart failure). During terminal illness, patients and parents might opt to stay in the hospital.

In addition to taking aggressive steps to treat the precipitating factor (infection, anemia), compliance with therapy has to be evaluated when symptoms persist.

Diminished absorption and waning action of diuretics can be partially overcome by parenteral administration of furosemide or by sequential segmental nephron blockade achieved by combining metolazone, a thiazide diuretic, with furosemide.

Intravenous infusions of beta agonists, such as dopamine and dobutamine, temporarily improve myocardial function and partly reverse the abnormal neuro-endocrine profile of chronic congestive heart failure. However, in the long-term, they increase myocardial irritability, leading to arrhythmia.

Intra-aortic balloon pump support may be successfully and safely used in patients with acute decompensated DCM as an urgent measure of cardiac support to stabilize the patient and maintain organ perfusion until transplantation is possible, until a ventricular assist device is placed, or until the patient recovers sufficiently to be weaned from intra-aortic balloon pump.^[39]

Cardiac resynchronization therapy with AV synchronous biventricular pacing has been successful in some children with DCM and left bundle branch block (LBBB). Optimization of resynchronization for children with DCM is still in the early stages.

Automatic implantable cardioverter-defibrillators (ICDs) reduce sudden death, and their efficacy has been clearly demonstrated in adults with chronic congestive heart failure. However, their use in children has been limited. Studies have reported on the efficacy of ICDs in children with DCM and other cardiomyopathies.^[40]

Studies in adults who died of heart failure report significant fatigue, dyspnea, and pain in the days before death. Concluding that a similar pattern would occur in children is logical.

Dietary requirements are high in children with DCM because of their catabolic state, recurrent infections, increased muscle activity, and need for rapid growth. Dietary intake may be inadequate consequent to the anorexia, dietary restrictions, malabsorption, diarrhea, and frequent exacerbations of heart failure.

Ensuring an appropriate and palatable diet is a challenge. Temporary nasogastric tube feedings may be required for sick and severely anorectic children. Infants might need intravenous alimentation for relief from feeding activity.

Powerful diuretics have largely obviated stringent restrictions on salt and fluid intake.

Enforced bed rest is impractical and probably unnecessary. Often, restriction of physical activity is self-enforced.

In patients with chronic illness, regular graded exercise has been shown to improve effort tolerance and quality of life. Activity to the limit of tolerance should be encouraged. Patients should avoid competitive sports.

All feasible support should be provided for peer interaction and participation in normal life activities. Restricted life activities, frequent diagnostic and therapeutic interventions, and an uncertain prognosis make these children prone to psychological problems that may significantly influence prognosis and outcome. Among the described abnormalities are inhibition of emotions, marked anxiety, depressive reaction with loneliness, low self-esteem, feelings of inadequacy, emotional lability, impulsiveness, and weakness of self-identity.