6. An "S3" heart sound is an extra sound heard early in ventricular diastole, corresponding to the time when there is rapid filling of the ventricle with blood. One theory regarding its cause is that the inflow of blood from the atria produces an oscillation of blood back and forth between the walls of the ventricles. Describe 2 conditions that may produce an S3 sound. How would you diagnose each of these? Describe the test you would perform and the result you expect for each.