Third heart sound: signs, symptoms, and causes

2021-08-28 09:59 PM

A sudden restriction of the left ventricular filling during early diastole causes pulsation of the heart wall and intracardiac blood, producing a T3 sound. Typically, a T3 sound is seen in patients with increased filling, increased volume, and a stiff, less elastic left ventricle.

Description

Heart sound is clear, cloudy, low frequency, heard during the rapid filling phase, early diastole. The rhythm of the heart sounds in a patient with T3 resembles the pronunciation of Kentucky.

Cause

Popular

Usually physiological in young patients (under 40 years of age).

Any cause of decreased ventricular function also causes a third heart sound.

Less popular

Other diseases: anemia, thyrotoxicosis, mitral regurgitation, HOCM, aortic regurgitation, and tricuspid regurgitation.

Mechanism

A sudden restriction of the left ventricular filling during early diastole causes pulsation of the heart wall and intracardiac blood, producing a T3 sound.

Typically, a T3 sound is seen in patients with increased filling, increased volume, and a stiff, less elastic left ventricle.

Significance

Hearing T3 is a symptom of reduced left ventricular function and is considered to have a poor prognosis in patients with heart failure.

It is used to predict left ventricular function or ejection fraction < 50% with a sensitivity of 51% and a specificity of 90%. There is strong evidence for its value in predicting LV hypertension (>15mmHg) with sensitivity 41%, specificity 92%, PPV 81, and NPV 65.

Related articles:

Heart failure

Lectures on heart failure treatment

Graphical analysis of compensated chronic and acute heart failure

Heart valves prevent the return of systolic blood

Heart: anatomy and function