By Steven Lome
Heart sounds are produced from a specific cardiac event such as closure of a valve or tensing of a chordae tendineae. Many pathologic cardiac conditions can be diagnosed by auscultation of the heart sounds. Note that heart sounds are discrete, short audible events from a specific cause which differs from a heart murmur. A murmur is due to tubrulance of blood flow and can at times encompass all of systole or diastole. The main normal heart sounds are the S1 and the S2 heart sound. The S3 can at times be normal, however may be pathologic. An S4 heart sound is almost always pathologic. Heart sounds can be decribed by their intensity, pitch, location, quality, and timing in the cardiac cycle.
Intensity: Heart sounds can be described as increased in intensity (loud), decreased in intensity (soft) or absent.
Pitch: Heart sounds can be described as either high pitched (heard best with the diaphragm of the stethoscope).
Location: The location of the heart sound can help determine the etiology. The standard listening posts (aortic, pulmonic, tricuspid and mitral) apply to both heart sounds and murmurs. For example, the S1 heart sound which consists of mitral and tricuspid valve closure is best heard at the tricuspid (left lower sternal border) and mitral (cardiac apex) listening posts.
Timing: The timing can be described as during early, mid or late systole or early, mid or late diastole.
Note that terms such as "click", "snap" or "knock" are sometimes used, although have no specific quality or meaning. They will be referenced in the following sections.
S1 Heart Sound
S2 Heart Sound
S3 Heart Sound
S4 Heart Sound
Extra Heart Sounds
Heart Sounds Multiple Choice Quesetions
Heart Sounds Jeopardy - Coming Soon!