Even the most proficient of emergency care providers have difficulty discerning the low frequency rumblings of an S3 or S4 from the background noise of monitors in a hectic emergency setting. Nearly half a century has passed since phonocardiography originally was developed to assist in cardiac auscultation. Modern technology is now making it possible to once again use the analysis and reporting of S3 and S4 heart sounds to facilitate the diagnosis of heart failure and acute coronary syndrome (ACS).