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diseasePediatric Dilated Cardiomyopathy
aliasCardiomyopathy
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bubble_chart Overview

In the past 20 years, pediatric dilated cardiomyopathy has been increasingly prevalent in China.

bubble_chart Diagnosis

(1) It is more common in school-age and preschool children.

(2) Physical examination, X-ray, and/or echocardiography reveal cardiac enlargement.

(3) Clinical manifestations include signs and symptoms of congestive heart failure.

(4) Electrocardiogram shows ST-T segment changes, conduction block, ectopic rhythm, and other abnormalities.

(5) Other cardiomyopathies and Keshan disease must be excluded.

bubble_chart Treatment Measures

﹝Treatment﹞

There is no specific treatment for this condition, and general comprehensive measures are mainly adopted:

(1) For those with cardiac enlargement and decreased cardiac function, long-term rest is recommended to avoid fatigue. Patients with heart failure must be absolutely bedridden until cardiac function significantly improves.

(2) Due to the extensive myocardial damage, tolerance to digoxin is relatively poor, and toxic reactions are prone to occur. Therefore, the maintenance dose method should be adopted, with the dose being only 2/3 or even 1/2 of the normal dose. Long-term application has certain efficacy, and diuretics and vasodilators should be routinely used.

(3) It is currently believed that heart failure in this condition involves not only systolic dysfunction but also diastolic dysfunction. The following drugs may help improve ventricular diastolic function:

  1. Calcium antagonists: They can reduce the concentration of Ca2+ in myocardial cells, thereby facilitating myocardial decontraction and improving myocardial compliance. Verapamil can be used at 2mg/kg per dose, 3–4 times daily. Diltiazem can also be used at 0.5mg/kg per dose, every 8 hours. If no discomfort occurs, the dose can be doubled after 2–4 weeks, which can improve clinical symptoms and cardiac function.
  2. Beta-blockers: Represented by propranolol and including atenolol, they can slow the heart rate and prolong ventricular filling time, thereby improving ventricular diastolic function.
  3. Phosphodiesterase inhibitors: It is known that insufficient cyclic adenosine monophosphate (cAMP) plays an important role in the physiological dysfunction of the myocardium in heart failure patients. cAMP enhances the diastolic relaxation process by activating sarcoplasmic reticulum calcium ATPase. In heart failure, cAMP is reduced in myocardial cells. Therefore, phosphodiesterase inhibitors that increase cAMP, such as amrinone and milrinone, can improve diastolic function in heart failure. The dose for the former is an initial intravenous bolus of 0.75 mg/kg, followed by an infusion of 5–10 μg/kg/min. Oral administration has significant side effects. For the latter, the pediatric dose is 1 mg/kg daily, divided into 3–4 oral doses, and can be administered long-term.

(4) Myocardial metabolic enzyme activators:

  1. Fructose-1,6-diphosphate: Promotes myocardial cell metabolism and increases myocardial energy and ATPase activity, showing good effects in clinical practice, with significant improvement in symptoms of refractory heart failure in children. The daily intravenous single dose is 0.7–1.6 ml/kg, with a maximum dose not exceeding 2.5 ml/kg (75 mg/ml). The intravenous injection speed is 10 ml/min.
  2. Coenzyme Q10: As a cofactor, it participates in several enzyme systems related to energy conversion. A deficiency of coenzyme Q10 may significantly affect myocardial function. The pediatric oral dose is 12.5 mg per dose, three times daily, with good long-term effects.

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