First Heart Sound: An Introduction for Cardiac Sonographers

Cardiac auscultation is an integral element of bedside cardiovascular assessment, offering valuable clinical insights. Complementing this, echocardiography serves as a powerful diagnostic imaging tool that enables detailed structural and functional visualization of the heart. Understanding various auscultatory findings and their correlation with corresponding echocardiographic features can enhance cardiac sonographers’ insight into a wide range of cardiovascular conditions. This is an introduction for cardiac sonographers on how foundational knowledge of cardiac auscultation can be integrated into an echocardiographic examination. The focus is on the first heart sound (S1), serving as a starting point to bridge auscultatory findings with imaging correlations. The findings from M-mode, pulse wave Doppler of atrioventricular valve inflows, and tissue Doppler of the mitral and tricuspid valve annuli can be systematically integrated with the characteristics of a patient’s S1. Such awareness can guide sonographers to explore relevant findings more intentionally during the examination and hopefully contributing to improved diagnostic accuracy.