(AS: aortic stenosis; ASD: atrial septal defect; HCM: hypertrophic cardiomyopathy; LBBB: left bundle

branch block; LV: left ventricular; MR: mitral regurgitation; pHTN: pulmonary hypertension; PVCs:

premature ventricular contractions; RBBB: right bundle branch block; RV: right ventricular; sHTN:

systemic hypertension; VSD: ventricular septal defect)

Valvular diseases and S2

MS Mild to moderate → normal

Severe MS with pHTN → loud P2

MR Mild to moderate → normal

Severe → wide and variable

MR + CAD/HOCM → reverese split

AS Severe AS → reverse split (severe AS)

AR Root pathology → A2 loud—tambour

Valvular pathology → A2 soft

(AR: aortic regurgitation; AS: aortic stenosis; CAD: coronary artery disease; HOCM: hypertrophic

obstructive cardiomyopathy; MR: mitral regurgitation; MS: mitral stenosis; pHTN: pulmonary

hypertension)

THIRD HEART SOUND (S3)

Third heart sound (S3) is a low-pitched early diastolic sound best heard with the bell. Also called as

ventricular sound or protodiastolic sound/gallop.

It coincides with rapid ventricular filling immediately after opening of the atrioventricular valves and is

therefore heard after the second sound as ‘lub-dub-dum’.

It is almost never heard at the base of heart (aortic and pulmonary area).

Less palpable than S4.

It is sign of ventricular systolic dysfunction.

Prerequisite

Nonobstructed AV valve.

Best head with bell

LVS3—left lateral position at apex during expiration.

RVS3—left sternal edge in supine position during inspiration.

Causes of S3

Physiological and hyperdynamic states Pathological LV S3 Pathological RV S3

Children

Under 40 years

Athletes

Pregnancy

Other hyperdynamic states

Left ventricular failure

Aortic regurgitation

Mitral regurgitation

Ischemic heart disease

Cardiomyopathy

Right ventricular failure

Endomyocardial fibrosis

PERICARDIAL KNOCK

Cause–sudden cessation of ventricular filling

Seen in–constrictive pericarditis

Timing–comes earlier than S3

Frequency–higher than S3.

Diastolic knock is a palpable pericardial knock in constrictive pericarditis.

Correlate with other clinical findings like:

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Rapid ‘y’ descent

Kussmaul sign

Systolic retraction of apex (broadbent’s sign)

Congestive hepatomegaly with ascites.

FOURTH HEART SOUND (S4)

It is a low frequency late diastolic or presystolic sound heard during atrial contraction.

It is also called as a presystolic or an atrial diastolic gallop (even though it is ventricular in origin).

Prerequisites:

Healthy contracting atrium.

Nonobstructive AV valve.

Noncompliant (stiff) ventricle.

Theories of production of S4:

Ventricular theory (rapid deceleration of incoming blood).

Impact theory (dynamic impact of the heart with chest wall).

Best head with bell.

LVS4—left lateral position at apex during expiration.

RVS4—left sternal edge in supine position during inspiration.

S4 may be confused with spilt S1. Firm pressure by the diaphragm of stethoscope eliminates S4 but

not split S1.

Causes of S4:

Physiological: >60 years

Pathological:

Pathological S4

RV S4 LV S4

Right ventricular hypertrophy due to:

Pulmonary hypertension

Pulmonary stenosis

Systemic hypertension

Hypertrophic cardiomyopathy

Ischemic heart disease (especially acute myocardial infarction)

Acute mitral regurgitation

Anemia, thyrotoxicosis and AV fistula

Note:

Triple gallop rhythm: S1, S2, S3 (or S4) with HR >100

Summation rhythm: S1, S2, S3, S4 with HR >100

CLICKS AND SNAPS

Clicks Snaps

High pitched systolic sounds High pitched diastolic sounds

Produced by aortic and pulmonary valve opening Produced by mitral and tricuspid valve opening

Clicks

Clicks Ejection clicks Non-ejection

clicks

Timing Early systolic Mid to late

systolic

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Pathology Vascular (dilated vessel) Valvular (diseased

valve)

Valve prolapse

Left sided

causes

Systemic hypertension

Aneurysm of aortic root

Bicuspid aortic valve Mitral valve

prolapse

Right sided

causes

Dilated pulmonary artery (idiopathic or secondary to pulmonary

arterial hypertension)

Congenital pulmonary

stenosis

Tricuspid valve

prolapse

Note: Pulmonary valvular ejection click seen in congenital pulmonary stenosis is the only event

occurring in the right side of the heart which is better heard on expiration.

Opening Snaps

High pitched diastolic sound occurring 0.04–0.12 seconds after A2 (S3 occurs 0.12 seconds after A2)

due to opening of mitral or tricuspid valves.

Occurs after S2 and before S3.

Mechanism of opening snap (OS):

Stenotic anterior mitral/tricuspid valve leaflet suddenly bulging downward into the ventricular

cavity like a dome, with a snapping sound when the valve is rapidly opened during diastole. So, OS is heard only if leaflets are mobile.

OS occurs when movement of valve suddenly stops, at point when ventricular pressure drops

below that of atrial pressure.

In mitral stenosis (MS):

It is the most important auscultatory sign of valvular involvement in MS (pathognomonic sign).

Absent OS indicates the calcification of body of the mitral leaflets.

The time interval between A2 and OS is inversely proportional to the severity of the MS.

Best heard: During expiration, just medial to the cardiac apex with the diaphragm of the stethoscope.

Other conditions with OS:

Mitral regurgitation (10%)

Tricuspid stenosis,

Atrial septal defect.

Differences between OS, split S2 and S3:

Opening snap (OS) S2 split S3

Area Medial to apex Base of heart At the apex

On standing A2-OS increases A2-P2 decreases Disappears

Pitch High High Low

Best heard Diaphragm Diaphragm Bell

Other sounds:

Tumor plop Seen in myxomas

Prosthetic valve sounds Metallic S1 heard with mechanical mitral valve

Metallic S2 heard with mechanical aortic valve

Note: Bioprosthetic valves heart sounds are normal.

PERICARDIAL RUB

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