Which heart sound is the loudest

The most audible are the high frequency components attributable to the closure of the aortic and pulmonic valves. When evaluating for splitting, listen in the 2nd and 3rd left intercostal spaces. Ask the patient to breathe quietly, and then a bit more deeply. During inspiration you should hear the inspiratory splitting of S2 into A2 and P2.

To the untrained ear this sounds more like a prolongation of sound rather than two distinct sounds. In general the interval between A2 and P2 is quite short, although in some situations the patient may have a widened interval. Next, listen for splitting of S2 to disappear during expiration. Related to the closure of the aortic and pulmonic valves.

Loudest at the base. You can relate the auscultatory findings to the cardiac cycle by simultaneously palpating the carotid artery while listening to the heart: S1 S2 Just precedes carotid pulse Follows carotid pulse Louder at apex Louder at base Lower pitch and longer than S 2 Higher pitch and shorter than S 2 Because systole is shorter than diastole: First of two grouped beats Second of 2 grouped beats If anything abnormal is found, move the stethoscope around until the abnormality is heard most clearly.

Analyze each category individually and then put it together to diagnosis the problem Category Definition Audio examples Aortic stenosis: Murmur: Harsh late-peaking crescendo-decrescendo systolic murmur Heard best- left 2nd ICS Radiation to the carotids. Possible associated findings: Abnormal carotid pulse Diminished and delayed "pulsus parvus and tardus" Sustained Apical impulse Calcified aortic valve on CXR Mitral Regurgitation: Murmur: Blowing holosystolic murmur Heard best at the apex Radiation to the axilla and inferior edge of left scapula.

Neck Veins. You can relate the auscultatory findings to the cardiac cycle by simultaneously palpating the carotid artery while listening to the heart: S1 S2 Just precedes carotid pulse.

Possible associated findings: Abnormal carotid pulse Diminished and delayed "pulsus parvus and tardus" Sustained Apical impulse Calcified aortic valve on CXR. Murmur: Blowing holosystolic murmur Heard best at the apex Radiation to the axilla and inferior edge of left scapula. To explore why an ASD results in a fixed split S2, we must consider the altered cardiac hemodynamics present, which result in a fixed delay in PV closure.

During inspiration, as usual, there is an increase in venous return to the right side of the heart and thus increased flow through the PV — delaying its closure. The alteration in a person with an ASD occurs during expiration. As the person expires, the pressure in the right atrium decreases because there is less venous return. The decreased pressure allows more blood to flow abnormally through the ASD from the high pressured left atrium to the right atrium, ultimately resulting again in increased flow through the pulmonic valve — again, delaying its closure.

The S3 sound is actually produced by the large amount of blood striking a very compliant LV. Enlarge If the LV is not overly compliant, as is in most adults, a S3 will not be loud enough to be auscultated.

A S3 can be a normal finding in children, pregnant females and well-trained athletes; however, a S4 heart sound is almost always abnormal. A S3 can be an important sign of systolic heart failure because, in this setting, the myocardium is usually overly compliant, resulting in a dilated LV; this can be seen in the image below.

Enlarge Normal LV vs. Dilated LV S3 Present. S3 is a low-pitched sound; this is helpful in distinguishing a S3 from a split S2, which is high pitched. A S3 heart sound should disappear when the diaphragm of the stethoscope is used and should be present while using the bell; the opposite is true for a split S2. Also, the S3 sound is heard best at the cardiac apex, whereas a split S2 is best heard at the pulmonic listening post left upper sternal border.

To best hear a S3, the patient should be in the left lateral decubitus position. If the LV is noncompliant, and atrial contraction forces blood through the atrioventricular valves, a S4 is produced by the blood striking the LV. Therefore, any condition that creates a noncompliant LV will produce a S4, while any condition that creates an overly compliant LV will produce a S3, as described above. A S4 heart sound can be an important sign of diastolic HF or active ischemia and is rarely a normal finding.

Diastolic HF frequently results from severe left ventricular hypertrophy, or LVH , resulting in impaired relaxation compliance of the LV. In this setting, a S4 is often heard.

Also, if an individual is actively having myocardial ischemia, adequate adenosine triphosphate cannot be synthesized to allow for the release of myosin from actin; therefore, the myocardium is not able to relax, and a S4 will be present. It is important to note that if a patient is experiencing atrial fibrillation, the atria are not contracting, and it is impossible to have a S4 heart sound.

Like S3, the S4 sound is low pitched and best heard at the apex with the patient in the left lateral decubitus position. Below is comparative information for S3 and S4. There are a few common extra heart sounds that the clinician may encounter.

Systolic ejection click: A systolic ejection click frequently indicates a bicuspid aortic valve. This sound is heard just after the S1 heart sound. Usually, the opening of the aortic valve is not audible; however, with a bicuspid aortic valve, the leaflets dome suddenly prior to opening and create a systolic ejection click. The click may be difficult to hear in the presence of significant AS. Mitral valve prolapse click: Mitral valve prolapse produces a mid systolic click, usually followed by a uniform, high-pitched murmur.

The murmur is actually due to MR that accompanies the MVP; thus, it is heard best at the cardiac apex. MVP responds to dynamic auscultation.