S2 is normally split because the aortic valve (A2) closes before the pulmonary valve (P2). The closing pressure (the diastolic arterial pressure) on the left is 80 mmHg as compared to only 10 mmHg on the right. This higher closing pressure leads to earlier closure of the aortic valve.

What causes a fixed split S2?

A fixed split S2 occurs when there is always a delay in the closure of the pulmonic valve, and there is no further delay with inspiration; compare this to a widened split S2, as described above.

What does fixed splitting of S2 mean?

Atrial septal defect and S2 splitting In ASD, there is fixed splitting of the second heart sound, meaning that the second heart sound is split throughout both expiration and inspiration.

Why does physiologic splitting occur?

Physiological S2 splitting is thought to occur due to changes in the timing of the closure of the pulmonary and aortic valves during the respiratory cycle.

When would you expect to hear a split S2?

Splitting of the S2 can happen during inspiration. It is heard when the aortic valve closes earlier than the pulmonic valve. Instead of it sounding like “dub” it sounds like “T-Dub”. You will hear this sound at the apex in the left lateral position.

Is S2 split normal?

The Auscultation Assistant – Split S2. The sound you are hearing now is a normal sinus rhythm with a splitting of S2. In this case, the splitting is due to a normal physiologic cause: respiration. In most healthy adults, a splitting of S2 can be heard during deep inspiration.

What causes an opening snap?

An opening snap occurring early in diastole along with a single second heart sound can mimic a split second heart sound. An opening snap is caused by thickened valve leaflets. When they open it produces a snapping sound. The more severe the thickening the earlier in diastole the opening snap occurs.

What Causes Split heart?

It is caused when the closure of the aortic valve (A₂) and the closure of the pulmonary valve (P₂) are not synchronized during inspiration. The second heart sound (S2) is caused by the closure of the aortic and pulmonic valves, which causes vibration of the valve leaflets and the adjacent structures.

What causes split S1?

This occurs when the mitral valve closes significantly before the tricuspid valve, allowing each valve to make a separate audible sound. Inspiration delays the closure of the tricuspid valve in a normal person, due to increased venous return, thereby enhancing the splitting of the S1 sound.

Where is split S2 best heard?

Splitting best heard in the 2nd left intercostal space, close to the sternal border. Second heart sounds are best heard when patients are semi-recumbent (30-40 degrees upright) and in quiet inspiration.

Why split is fixed in ASD?

The most common cause of fixed splitting is an atrial septal defect. In such an event, a chronic volume overload of the right-sided circulation results in a high-capacitance, low-resistance pulmonary vascular system.

Why does VSD cause fixed splitting?

The splitting of S2 is “fixed” and does not vary with respiration. This is due to diminished effects of respiratory cycle on the right ventricular volume. In inspiration, the venous return to the right atrium increases and impedes the left to right shunt across the ASD.

Why do you get fixed splitting in ASD?

However, when present, it almost always indicates an atrial septal defect (ASD). A fixed split S2 occurs when there is always a delay in the closure of the pulmonic valve and there is no further delay with inspiration (compare this to a widened split S2 as described above).

At what site would you expect to hear a normal split S1 a split S2?

Normally, S1 is louder than S2 at the apex, and softer than S2 at the base of the heart. Pathologic changes in the intensity of S1 relative to S2 may be seen in certain disease states.

Does mitral valve stenosis cause pulmonary hypertension?

Like other heart valve problems, mitral valve stenosis can strain your heart and decrease blood flow. Untreated, mitral valve stenosis can lead to complications such as: High blood pressure in the lung arteries (pulmonary hypertension).