1 00:00:03,668 --> 00:00:07,209 Heart sounds that are soft and difficult to hear 2 00:00:07,209 --> 00:00:08,916 are most common when there is something 3 00:00:08,916 --> 00:00:11,497 between the heart and the stethoscope. 4 00:00:11,497 --> 00:00:13,268 Common causes include 5 00:00:13,268 --> 00:00:16,873 pericardial effusion (fluid surrounding the heart), 6 00:00:16,873 --> 00:00:21,652 pleural effusion (fluid present in the thoracic cavity around the lungs), 7 00:00:21,652 --> 00:00:23,572 and obesity.