Аудіо 00038. Venous hum

This physically fit boy underwent echocardiography as a neonate because of mother's diabetes and was found to have a healthy heart. Now referred because of a strong murmur. ECG and chest radiograph are normal, auscultation reveals a systolic-diastolic second-degree murmur that it loudest in early diastole. Venous hum is sometimes a misleadingly loud murmur. It is caused by flow in the jugular veins under the clavicle bone to the superior vena cava. This sound is intensified when the head is turned to the left and disappears when lying flat. The hum is heard best in right second intercostal space and medially up behind the sternum. The hum is not necessarily heard on every auscultation. The phonogram shows a rather flat contour, and the spectrogram contains 300 Hz and 400 Hz frequencies at the beginning of diastole when the venous return is fastest. Respiratory sounds are also loud in the area of auscultation, which sometimes makes interpretation of the curves difficult. Age 1.7 years. Auscultation area: right second intercostal space (RIC2).