Acquired Pediatric Cardiac Disease, Cardiomyopathy, and Ventricular Function Assessment
Acquired disease
Kawasaki disease is the dominant acquired coronary disease of childhood: look for perivascular brightness, ectasia, and aneurysms, measured as z-scores; giant aneurysms (8 mm or more) carry the highest thrombosis risk. Myocarditis presents with global dysfunction, often with a small pericardial effusion. Acute rheumatic carditis produces mitral regurgitation far more often than stenosis in children. Pericardial effusion assessment includes size, distribution, and signs of tamponade (right-sided diastolic collapse, IVC plethora, respiratory inflow variation).
Cardiomyopathies
Dilated cardiomyopathy: spherical, thin-walled LV, reduced fractional shortening (below about 25 percent is clearly abnormal), frequent mitral regurgitation, and a poor prognosis - function may improve with time, so serial assessment matters. Hypertrophic cardiomyopathy: asymmetric septal hypertrophy, systolic anterior motion of the mitral leaflet, dynamic LVOT obstruction, and diastolic dysfunction; avoid vasodilators and dehydration, and note that a resting gradient may be absent (provoke with Valsalva or exercise). Restrictive cardiomyopathy: biatrial enlargement with normal or near-normal ejection fraction and restrictive filling - a normal EF in a child with huge atria is a warning sign, not reassurance.
Function assessment
Ejection fraction by biplane Simpson and fractional shortening by M-mode are load-dependent; report them alongside loading conditions, valve regurgitation, and heart rate. TAPSE and MAPSE measure longitudinal excursion, speckle-tracking strain detects early dysfunction before EF falls (and is angle-independent but vendor-dependent), and the myocardial performance (Tei) index combines systolic and diastolic time intervals. In children, normal EF is roughly 55–65 percent, and single-plane measurements should be avoided when biplane is feasible.
Trap: a normal ejection fraction does not exclude significant myocardial disease.