This child was referred for investigation of a murmur. ECG shows high left ventricle potentials, left ventricle appears prominent on chest radiograph and pulmonary vasculature is mildly engorged. On auscultation the typical machine-like sound of ductus arteriosus is heard, which is clearly louder in systole compared with diastole. The pulses are throbbing. Echocardiography shows a patent ductus arteriosus with normal pressure. Flow velocity increases towards the endsystole and slows down during diastole. In endsystole the pressure gradient between the aorta and the pulmonary artery is at its highest, and this is seen on the phonogram as a change in the loudness of the sound. The highest frequencies on the spectrogram are over 600 Hz at the end of systole. This child's ductus has consequently been closed with a coil. Age 0.8 years, weight 8.2 kg. Area of auscultation: left second ic (LIC2).