A paediatrician detected a murmur suggesting heart defect in this symptomless, well-developed, chubby boy. The murmur was not identified at later consultations, apparently it was partially masked by respiratory sounds or was confused with them. A third-degree coarse, stenosis-type murmur that does not quite last until the end of systole is heard in the aortic area. ECG and chest radiograph are within the normal range, upper and lower extremity blood pressures are normal. Echocardiography revealed aortic valve stenosis with a 45-mmHg flow gradient. Phonogram shows a diamond-shaped murmur, spectrogram contains early systolic sound waves of approx. 600 Hz that coincide with peak aortic flow. Age 0.6 years, height 70.0 cm, weight 9.0 kg.