Which heart sound could potentially indicate hypertrophic ventricles?

The fourth heart sound, or S4, is associated with conditions that cause increased resistance to filling the ventricles, such as hypertrophic cardiomyopathy. In individuals with hypertrophic ventricles, the thickened heart muscle can lead to a decrease in the ventricular chamber size and an increase in stiffness. This stiffness means that the heart requires more forceful contractions to fill effectively, which often results in the S4 sound being generated during the late diastolic phase when the atria contract to push blood into the stiff ventricle.

S4 is referred to as an "Atrial Gallop" because it occurs just before S1, caused by vibrations from the atrial contraction against a non-compliant ventricle. This sound is particularly prominent in patients with conditions like hypertension and aortic stenosis, as well as prominently in those with hypertrophic cardiomyopathy.

Understanding the significance of S4 can provide invaluable insight into the underlying heart mechanics and structural changes that might be occurring, making it a key clinical finding in assessing patients with possible hypertrophied cardiac ventricles.