Why does the lub sound occur around the peak of the R wave?

The “lub” sound occurs during the early phase of ventricular contraction and is produced by closing of the atrioventricular valves, which prevents blood backflow into the atria. When the ventricles relax, the blood pressure drops below what is in the arteries and the semilunar valves close, producing the “dub” sound.

What is the R lub interval?

The R-Lub Interval, which is the time interval between the peak of a R wave and the onset of the event mark. The onset of the event mark indicates the occurrence of the first heart sound or “lub”.

What does S1 heart sound represent?

The first heart sound (S1) represents closure of the atrioventricular (mitral and tricuspid) valves as the ventricular pressures exceed atrial pressures at the beginning of systole (point a). S1 is normally a single sound because mitral and tricuspid valve closure occurs almost simultaneously.

Why does the first heart sound occur after the QRS complex quizlet?

Explain why the first heart sound occurs after the QRS complex. QRS represents ventricular depolarization. This depolarization initiates ventricular contraction which closes the mitral and tricuspid valves. It is the closure that is heard as the first heart sound.

Which occurs first after the QRS complex occurs?

The QRS complex represents depolarization of the ventricles and is followed by ventricular contraction.

Why does the DUPP heart sound occur during the T-wave?

The heart tone “lub,” or S1, is caused by the closure of the mitral and tricuspid atrioventricular (AV) valves at the beginning of ventricular systole. The heart tone “dub,” or S2 ( a combination of A2 and P2), is caused by the closure of the aortic valve and pulmonary valve at the end of ventricular systole.

Where is the lub heart sound heard in relation to the ECG Why?

S1 – The first heart sound (lub) can be heard the loudest at the mitral area. This sound represents the closure of the mitral and tricuspid valves and is a low pitched, dull sound at the beginning of ventricular systole.

Is the time between lub R wave and DUP T wave always the same Explain why or why not?

As we know, the sounds ”lub” and ”dub” are heard when the mitral and tricuspid valves and the aortic and pulmonary valves are closed, respectively. So, the time delay between the T-wave and the dub sound is always the same.

What causes the first heart sound?

When is the S2 heart sound heard?

S2 is produced in part by hemodynamic events immediately following closure of the aortic and pulmonic valves. The vibrations of the second heart sound occur at the end of ventricular contraction and identify the onset of ventricular diastole and the end of mechanical systole.

Why is there a delay between the peak of the R wave and the peak of the finger blood flow?

The electrical activity of the heart always precedes mechanical contraction. Therefore, there will be significant delays between the R wave of the ECG and the rising phase of the pulse wave. The delay will be even greater at the finger is further away from the heart.