Murmurs

Question 1

What is S1 caused by?

Answer 1

The first heart sound (S1) is caused by the closing of the atrioventricular valves (the tricuspid and mitral valves) at the start of the systolic contraction of the ventricles.

Question 2

What is S2 caused by?

Answer 2

The second heart sounds (S2) is caused by the closing or the semilunar valves (the pulmonary and aortic valves) once the systolic contraction is complete.

Question 3

What is S3 caused by?

Answer 3

A third heart sound (S3) is heard roughly 0.1 seconds after the second heart sound. When there is rapid ventricular filling it causes the chordae tendineae to pull to their full length and twang like a guitar string.

This can be normal in young (15-40 years) healthy people because the heart functions so well that the ventricles easily allow rapid filling.

In older patients it can indicate heart failure, as the ventricles and chordae are stiff and weak so they reach their limit much faster than normal. Picture this like tight hamstrings in an old de-conditioned patient sharply tightening as they start to bend over.

Question 4

What is S4 caused by?

Answer 4

A fourth heart sound (S4) is heard directly before S1.

This is always abnormal and relatively rare to hear.

It indicates a stiff or hypertrophic ventricle and is caused by turbulent flow from an atria contracting against a non-compliant ventricle.

Question 5

Where to listen to each valve?

Answer 5

Pulmonary: 2nd I.C.S left sternal boarder

Aortic: 2nd I.C.S right sternal boarder

Tricuspid: 5th I.C.S left sternal boarder

Mitral: 5th I.C.S mid clavicular line (apex area)

Question 6

What special manoeuvres can be used to emphasise valve sounds?

Answer 6

Patient on their left hand side (mitral stenosis)

Patient sat up, learning forward and holding exhalation (aortic regurgitation)

Question 7

SCRIPT mnemonic for assessing murmur.

Answer 7

Site

Character (soft/blowing/crescendo/decrescendo/crescendo-decrescendo)

Radiation

Intensity (What grade?)

Pitch (High pitched or low and grumbling, pitch indicates velocity)

Timing (systolic vs. diastolic)

Question 8

Murmur grades

Answer 8

If in doubt it’s probably 2 or 3.

1 - Difficult to hear

2 - Quiet

3 - Easy to hear

4 - Easy to hear with a palpable thrill

5 - Can hear with stethoscope barely touching chest

6 - Can hear with stethoscope off the chest

Question 9

Give different radiations of mumurs.

Answer 9

Over carotids -> AS

Left axilla -> MR

Question 10

What does each valve disease cause in terms of heart hypertrophy/dilatation?

Answer 10

MS - left atrial hypertrophy

AS - left ventricular hypertrophy

MR - left atrial dilatation

AR - left ventricular dilatation