What does heart sound S4 typically indicate?

Heart sound S4, also known as an atrial gallop or presystolic gallop, typically indicates that there is a stiff or hypertrophied ventricle; it is most commonly associated with conditions such as myocardial infarction or cardiomegaly. The presence of S4 suggests that there is an increased resistance to filling the ventricle during diastole, which may arise from the ventricle’s decreased compliance.

In cases of myocardial infarction, the heart muscle can become damaged leading to ischemia and subsequent heart failure, resulting in ventricular hypertrophy or stiffness. Similarly, cardiomegaly, which refers to an enlarged heart often due to chronic conditions, can lead to impaired diastolic filling, manifesting as an S4 heart sound. This sound occurs just before the first heart sound (S1) and indicates that the atria are contracting against a stiff ventricle, thereby contributing to the clinical picture of heart failure or other related cardiac conditions.

Understanding this context helps clarify why S4 is not typically associated with the other options presented. For instance, while aortic stenosis might produce an S4 sound due to left ventricular hypertrophy, it is more specifically linked to the level of outflow obstruction and