What condition might cause an increased S4 heart sound?

An S4 heart sound is associated with increased pressure in the atria due to decreased compliance of the ventricles. This sound, often described as an "atrial gallop," typically occurs just before the S1 heart sound during late diastole. Aortic stenosis fits this description because it is characterized by the narrowing of the aortic valve, leading to increased pressure in the left ventricle as it works harder to overcome the obstruction. This elevated ventricular pressure can subsequently lead to reduced ventricular compliance, which is a key factor in generating the S4 sound as the atria contract to push blood into a stiffened ventricle.

In the context of other conditions, while heart failure can also lead to an S4 sound, it is more indicative of longstanding cardiac problems rather than the specific hemodynamic changes associated with aortic stenosis. Arrhythmias may influence cardiac output and rhythm but do not directly correlate with the increased stiffness of the ventricle that leads to an S4. Myocardial infarction can also alter heart sounds but primarily affects early diastolic sounds due to changes in cardiac compliance post-infarction, rather than causing a well-defined S4 sound as seen in cases of aortic stenosis. Thus