Which cardiovascular condition is characterized by the presence of a third heart sound (S3)?

The presence of a third heart sound (S3) is often associated with heart failure. This sound typically occurs during the rapid filling phase of the ventricles when blood flows from the atria to the ventricles. In heart failure, the ventricles are often dilated or have impaired filling, leading to this abnormal sound. The S3 is indicative of increased blood flow or turbulent flow associated with higher pressures within the heart chambers, which is common in heart failure.

While S3 can appear in other conditions, it is most classically and frequently linked with heart failure due to the volume overload and reduced contractility characteristics of the heart in this condition. This distinguishing feature makes heart failure the primary condition where S3 is acknowledged and serves as a clinical marker for potential cardiac issues.