Fourth heart sound: signs, symptoms and causes

2021-08-28 10:37 PM

The pressure contraction of the atria ejecting blood into the left ventricle is less elastic. Blood is stopped suddenly due to the stiffening of the left ventricular wall creating a low-frequency noise caused by movement and is considered a fourth heart sound

Image. Heart sounds (S1, S2, S3, S4)

Description

The fourth heart sound is the sound heard under normal T1 and T2 conditions. It is often described as a low-pitched sound heard at the end of diastole concurrently with atrial systole. Unlike the third heart sound, heard at the beginning of the diastole.

Cause

S4 is often considered typical in situations of LV hypo elasticity or diastolic dysfunction. Any condition that causes left ventricular sclerosis causes T4.

Popular

Hypertension with left ventricular hypertrophy.

Artery stenosis

Hypertrophic cardiomyopathy.

Changes due to anemia.

Aged

Less popular

T4 can also be heard in the presence of rapid filling, such as ischemia (causing increased cardiac output) and mitral regurgitation.

Mechanism

The pressure contraction of the atria ejecting blood into the left ventricle is less elastic. Blood is stopped suddenly due to the stiffening of the left ventricular wall creating a low-frequency noise caused by movement and is considered a fourth heart sound.

Significance 

Evidence of the usefulness of T4 is uncertain. Several studies have shown an association between left ventricular sclerosis and T4 as pathological symptoms. Other studies have found no valid association between impaired diastolic function and the presence of a fourth heart sound, suggesting that this is an insensitive and less specific finding.

Using barograms, studies have shown that T4 is present in 30-87% of patients with heart disease but also in 55-75% of people without heart disease.

Related articles: 

Normal heart sound: listen to the heart with a stethoscope

Split heart sound: signs, symptoms, and causes

Third heart sound: signs, symptoms, and causes

Strong first heart sound: signs, symptoms and causes

Faint first heart sound: signs, symptoms, and causes