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 caused the second heart sound?
The second heart sound (S2) is produced by the closure of the aortic and pulmonic valves. The sound produced by the closure of the aortic valve is termed A2, and the sound produced by the closure of the pulmonic valve is termed P2.
Why is the second heart sound louder than the first?
The loudness of each component of the second heart sound is proportional to the respective pressures in the aorta and pulmonary artery at the onset of diastole. Dilatation of the aorta or pulmonary artery may also cause accentuation of the aortic and pulmonic components, respectively.
What does a loud second heart sound mean?
The second heart sound (S2) represents closure of the semilunar (aortic and pulmonary) valves (point d). S2 is normally split because the aortic valve (A2) closes before the pulmonary valve (P2).
Where do you hear S2 heart sounds?
Exam Technique in Second Heart Sounds
- Splitting best heard in the 2nd left intercostal space, close to the sternal border.
- Use the diaphragm of your stethoscope.
- Second heart sounds are best heard when patients are semi-recumbent (30-40 degrees upright) and in quiet inspiration.
Which heart sound is the loudest?
Normal Heart Sounds
S1 is longer, louder, duller, and lower-pitched than the second heart sound. It is loudest over the mitral and tricuspid areas. It is loudest in young, thin animals and those with high sympathetic tone (e.g., fear), tachycardia, systemic hypertension, anemia, or mitral regurgitation.
What is a S3 gallop?
The third heart sound (S3), also known as the “ventricular gallop,” occurs just after S2 when the mitral valve opens, allowing passive filling of the left ventricle. … A S3 can be a normal finding in children, pregnant females and well-trained athletes; however, a S4 heart sound is almost always abnormal.
Is lub louder than dub?
S1 – The first heart sound (lub) can be heard the loudest at the mitral area. … S2 – The second heart sound (dub). This is best heard at the base of the heart at the end of ventricular systole.
Why is S1 louder at the apex?
The intensity of S1 depends upon: the position of the AV valves at the onset of ventricular systole, the structure of the leaflets themselves, and the rate of pressure rise in the ventricle. Normally, S1 is louder than S2 at the apex, and softer than S2 at the base of the heart.
What is the time gap between two heart sounds?
Splitting of the first heart sound into its two audible components, M1 and T1, is a normal finding on cardiac auscultation. The M1–T1 interval is normally separated by 20 to 30 msec. The fact that the first heart sound is split may be helpful in certain disease states.
How can you tell the difference between first and second heart sounds?
The first heart sound is produced by the closing of the mitral and tricuspid valve leaflets. The second heart sound is produced by the closing of the aortic and pulmonic valve leaflets. The second heart sound is unsplit when the subject is holding his or her breath at peak expiration.
Which condition can cause a wide split in the second heart sound?
Wide splitting of S2 refers to an increase in the usual splitting that persists throughout the respiratory cycle. Wide splitting can be caused by delayed closure of the pulmonic vaive (as in pulmonic stenosis or right bundle branch block.)
What is second heart?
The second heart is a system of muscles, veins, and valves in the calf and foot that work together to push deoxygenated blood back up to the heart and lungs. Vein valves act as trapdoors that open and close with each muscle contraction to prevent the backflow of blood.
What are the 5 cardiac landmarks?
The aortic, pulmonic, tricuspid, and mitral valves are four of the five points of auscultation.
What is Erb’s point?
“Erb’s point” is the fifth point of auscultation for the heart exam, located in the third intercostal space close to the sternum. It has sometimes been attributed to famous German neurologist Wilhelm Heinrich Erb (1840 – 1921), but without historical evidence.