What pathophysiological change is typically associated with S4 heart sounds?

The presence of an S4 heart sound, also known as an atrial gallop, is typically associated with a stiff or hypertrophic ventricle. This sound occurs just before the S1 heart sound and is generated when the atria contract, forcing blood into a ventricle that is not compliant or has reduced ability to stretch due to hypertrophy or stiffness. This condition is often seen in patients with hypertension or aortic stenosis, where the left ventricle becomes hypertrophied due to the increased afterload. The reduced compliance of the ventricle leads to higher pressures, causing the characteristic sound during late diastole.

While increased preload, fluid overload, and decreased myocardial contractility can impact cardiac function and may lead to other heart sounds, they do not specifically correlate with the presence of an S4 heart sound. Increased preload is usually associated with an S3 heart sound, while decreased myocardial contractility typically leads to heart failure symptoms but does not directly cause an S4. Thus, the stiff or hypertrophic ventricle is the primary factor that gives rise to the S4 heart sound.