Pediatric Cardiomyopathy¶

Learning Objectives¶

Core Knowledge & Clinical Reasoning¶

[ ] Apply the three principles of CM management: (1) identify pathophysiology, (2) determine root cause, (3) patient-specific therapy
[ ] Differentiate DCM, HCM, RCM, and ARVC by clinical and imaging characteristics
[ ] Identify phenocopies requiring specific treatment (Fabry, Pompe, mitochondrial, Barth)
[ ] Evaluate indications for genetic testing and interpret results

Management¶

[ ] Formulate evidence-based medical therapy for systolic vs diastolic dysfunction
[ ] Determine indications for ICD placement and transplant evaluation
[ ] Select appropriate monitoring and surveillance protocols by CM type

Communication & Counseling¶

[ ] Counsel families on genetic testing implications, inheritance patterns, and cascade screening
[ ] Discuss prognosis and expected disease trajectory with newly diagnosed patients
[ ] Address end-of-life considerations and advanced care planning when appropriate

Systems-Based Practice¶

[ ] Coordinate multidisciplinary care including genetics, metabolic specialists, and social work
[ ] Ensure appropriate family screening based on genetic testing results

Key Guidelines¶

2023 AHA Scientific Statement: Treatment Strategies for Cardiomyopathy in Children Circulation. 2023;148:174-195

Three Principles of Management¶

Identify underlying cardiac pathophysiology (systolic vs diastolic dysfunction, arrhythmia risk)
Determine root cause for patient-specific therapy
Treat based on clinical situation (stable vs acute)

Cardiomyopathy Types in Children¶

Dilated Cardiomyopathy (DCM)¶

Most common (~60% of pediatric cardiomyopathies)
LV dilation with reduced systolic function
Etiologies: Idiopathic, genetic, myocarditis, toxins, metabolic

Hypertrophic Cardiomyopathy (HCM)¶

See Topic 3 for comprehensive coverage
~25-30% of pediatric cardiomyopathies

Restrictive Cardiomyopathy (RCM)¶

Rare but poor prognosis
Diastolic dysfunction, biatrial enlargement
High risk of pulmonary hypertension

Left Ventricular Noncompaction (LVNC)¶

Excessive trabeculation
May overlap with DCM phenotype
Arrhythmia and thromboembolism risk

Arrhythmogenic Cardiomyopathy (ACM)¶

Fibrofatty replacement of myocardium
RV classically (ARVC) but LV involvement common
Exercise-related SCD risk

Dilated Cardiomyopathy¶

Rule Out Secondary Causes¶

Inflammatory: Myocarditis (CMR, biopsy)
Ischemic: Coronary anomalies (rare)
Toxic: Chemotherapy (anthracyclines)
Metabolic: Carnitine deficiency, thyroid
Arrhythmia-induced: Tachycardia-mediated

Genetic Evaluation¶

Recommended for ALL children with cardiomyopathy
Panel testing or WES
~30% of "idiopathic" DCM have identifiable genetic cause
Guides family screening

Medical Treatment¶

Drug Class	Examples	Notes
ACE inhibitors	Enalapril, lisinopril	First-line
Beta-blockers	Carvedilol, metoprolol	Add if stable
Diuretics	Furosemide, spironolactone	Symptom management
ARNI	Sacubitril/valsartan	Emerging pediatric data

ICD Indications¶

LVEF <35% with symptoms
LMNA mutations with conduction disease
Prior cardiac arrest or sustained VT

Phenocopies to Rule Out¶

Critical because specific treatments exist:

Condition	Test	Treatment
Fabry disease	Alpha-gal A, genetic	Enzyme replacement
PRKAG2	Genetic testing	May need pacemaker
Noonan syndrome	Clinical, genetic	Supportive
Mitochondrial	Muscle biopsy, genetic	Supportive +/- supplements
Pompe disease	GAA enzyme, genetic	Enzyme replacement
Danon disease	LAMP2, genetic	Consider transplant early

Genetic Testing Recommendations¶

ALL children with cardiomyopathy should have genetic testing
Positive result → cascade testing in first-degree relatives
Negative result doesn't exclude genetic cause (novel variants)
VUS interpretation requires expertise

Board Pearls¶

Pearl: Genetic testing recommended for ALL children with cardiomyopathy

~30% of "idiopathic" have identifiable genetic cause

Pearl: Rule out phenocopies - specific treatments exist

Fabry (ERT), Pompe (ERT), Danon (early transplant)

Pearl: LMNA mutations + DCM + conduction disease = ICD

High risk of sudden death

Self-Assessment¶

Q1: A 5-year-old is diagnosed with DCM (EF 30%). Echo shows no other abnormalities. Genetic testing returns positive for LMNA mutation. What additional management is indicated?

Answer

**Answer**: ICD implantation should be strongly considered **Rationale**: LMNA mutations are associated with high risk of sudden cardiac death, particularly when combined with conduction disease or LV dysfunction. Per 2023 AHA guidelines, ICD is indicated for LMNA + cardiomyopathy with conduction abnormalities or significant LV dysfunction.

Q2: A 10-year-old presents with LVH on echo. Parents mention he has learning difficulties and mild hearing loss. What should be considered?