Which condition can cause a wide split in the second heart sound?

The most common cause of paradoxical splitting of the second sound is left bundle branch block. Obstruction to left ventricular outflow of sufficient severity to delay aortic valve closure may also cause paradoxical splitting. In the context of aortic stenosis, such an auscultatory finding implies severe obstruction.

What causes wide split S2?

Wide splitting of S2 is caused either by a delay in the pulmonic component of S2 or by shortening of left ventricular systole with earlier occurrence of A2.

What is the physiological reason for splitting of the 2nd heart sound?

A split S2 is a finding upon auscultation of the S2 heart sound. It is caused when the closure of the aortic valve (A2) and the closure of the pulmonary valve (P2) are not synchronized during inspiration.

Why does Fixed splitting occur?

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).

Why is there no fixed splitting in VSD?

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.

What caused the first and second heart sounds?

First heart sound: caused by atrioventricular valves – Mitral (M) and Tricuspid (T). Second heart sound caused by semilunar valves – Aortic (A) and Pulmonary/Pulmonic (P).

What is the second heart sound caused by?

The second heart sound (S2) is produced by the closure of the aortic (A2) and the pulmonary valves (P2) at the end of systole. Refer to the audio example below. A2 is best heard at the aortic area (second right intercostal space); P2 is best heard at the pulmonary area.

What causes S3?

Third Heart Sound S3 Results from increased atrial pressure leading to increased flow rates, as seen in congestive heart failure, which is the most common cause of a S3. Associated dilated cardiomyopathy with dilated ventricles also contribute to the sound.

What is fixed splitting?

Fixed splitting: Spitting at both expiratory and inspiratory phases but does NOT lengthen with inspiration. Dx: ASD (due to continuous blood flow from left side to right side leading lenthened cardiac cycle on the right side of the heart), Right heart failure, Pulmonary Hypertension.

What causes fixed splitting in atrial septal defect?

The most characteristic feature of an atrial septal defect is the fixed split S2. As mentioned in the murmur overview, a split S2 is caused physiologically during inspiration because the increase in venous return overloads the right ventricle and delays the closure of the pulmonary valve.

Why does VSD cause left ventricular hypertrophy?

This shunting of blood results in volume overload to the left side of the heart due to pulmonary vascular overcirculation. Left ventricular eccentric hypertrophy results from the volume overload. Left-sided congestive heart failure can develop.