The fourth heart sound or S4 is an extra heart sound that occurs during late diastole, immediately before the normal two "lub-dub" heart sounds (S 1 and S 2).

The fourth heart sound is a low-pitched sound coincident with late diastolic filling of the ventricle due to atrial contraction. It thus occurs shortly before the first heart sound.

In a healthy adult, the heart makes two sounds, commonly described as ‘lub’ and ‘dub.’ The third and fourth sounds may be heard in some healthy people, but can indicate impairment of the …

2022年10月11日 · What is the S4 heart sound and what does it indicate? Why listen for S4 sounds? An S4 heart sound is a low-pitched sound that occurs toward the end of the diastole. …

The fourth heart sound (S4), when audible, is caused by the vibration of the ventricular wall during atrial contraction. This sound is usually associated with a stiffened ventricle (low ventricular …

The following synonyms are used for the fourth heart sound (S4): atrial gallop and presystolic gallop. S4 is a low-pitched sound (20–30 Hz) heard in presystole, i.e., shortly before the first …

The fourth heart sound (S4), also known as the “atrial gallop,” occurs just before S1 when the atria contract to force blood into the left ventricle.