Where will an S4 heart sound (S4) typically be heard during auscultation?

An S4 heart sound, also known as a "gallop," is typically heard over the apex of the heart and occurs just before the first heart sound (S1). This sound is generated during the atrial contraction phase of the cardiac cycle, which precedes S1 as the ventricles are filling with blood. In healthy individuals, this sound is usually not present, but it can be indicative of certain conditions such as hypertension, ventricular hypertrophy, or decreased ventricular compliance.

Understanding the location of S4 is crucial for accurate auscultation skills, as this allows healthcare providers to identify potential heart issues. The location at the apex corresponds to the point of maximal impulse and signifies that blood is being forced into a stiff or hypertrophied left ventricle, often associated with pathological states. This is why recognizing the timing (preceding S1) and location is important in clinical assessments.