Comparative Efficacy of ARNI Versus ACE Inhibitor Therapy in Egyptian Children With Dilated Cardiomyopathy

Inclusion Criteria: * Age 1 month to 18 years Diagnosed with dilated cardiomyopathy via echocardiography LVEDD z-score \> 2 (indexed to body surface area or age) LVEF \<45% and FS \<25% Clinically stable for ≥2 weeks prior to enrollment Receiving optimized guideline-based heart failure therapy (excluding ACEI/ARNI prior to study) Exclusion Criteria: * Known hypersensitivity/contraindications to ACEIs or ARNIs Severe renal impairment (eGFR \<30 mL/min/1.73 m²) Persistent hyperkalemia (K+ \>5.5 mmol/L) Other cardiomyopathies (hypertrophic, restrictive) or unrelated congenital/structural heart disease Severe hepatic impairment