Med Quizzes

Pediatric Murmurs: PDA vs ASD/ECD vs PS vs Williams

Pediatric Murmurs Cheatsheet

Key Concept: PDA produces a CONTINUOUS murmur (aortic > pulmonary pressure throughout cycle); ASD produces a systolic flow murmur (not from the defect itself). Distinguish by murmur timing and associated features.

Diagnosis	Key Features
PDA	Continuous (machinery) murmur maximal at S2 Bounding/accentuated peripheral pulses Best heard left infraclavicular/posterior interscapular Aortic pressure > pulmonary pressure throughout cardiac cycle → continuous flow Left-to-right shunt: aorta → pulmonary artery Large PDA: respiratory distress, poor feeding, LV failure, pulmonary overcirculation
ASD / Endocardial Cushion Defect	Associated with Down syndrome (trisomy 21) Pulmonic flow murmur (NOT from ASD itself — RV volume overload) Fixed split S2 (equal right and left heart filling) May involve AV valves (mitral/tricuspid regurgitation) NOT a continuous murmur (low pressure gradient across atria)
Pulmonary Stenosis	Systolic ejection murmur, crescendo-decrescendo at left upper sternal border Ejection click that decreases with inspiration (valvular PS) Right heart volume overload; soft P2
Williams Syndrome	Supravalvular aortic stenosis → crescendo-decrescendo systolic murmur Elfin facies, intellectual disability, hypercalcemia, friendly personality Murmur louder in right arm than left arm (due to supravalvular jet)