Cardiac Sounds and Murmurs

Question 1

PMI

Answer 1

• left ventricle, behind the RV and to the left, forms the left lateral margin of the heart
• inferior tip = cardiac apex
• 5th intercostal space at mid clavicular line
• not always palpable
• in supine position, may be as large as 1-2.5 cm
• size >2.5 cm = left ventricular hypertrophy from hypertension or aortic stenosis
• displacement of the PMI lateral to midclavicular line or >10cm lateral to midsternal line occurs in LVH and in ventricular dilation from MI or heart failure

Question 2

S3

Answer 2

corresponds to an abrupt deceleration of inflow across mitral valve

Question 3

S4

Answer 3

due to increased left ventricular end diastolic stiffness which decreases compliance

Question 4

Wide Physiologic Splitting of S2

Answer 4

• increase in the usual splitting of S2 during inspiration that persists throughout the respiratory cycle
• caused by delayed closure of the pulmonic valve (pulmonic stenosis or right bundle branch block) or early closure of the aortic valve (mitral regurgitation)

Question 5

Fixed Splitting

Answer 5

• refers to wide splitting that does not vary with respiration
• often due to prolonged right ventricular systole, seen in atrial septal defect (when pulse is regular) and in right ventricular failure

Question 6

Paradoxical or reversed splitting

Answer 6

• refers to splitting that appears on expiration and disappears on inspiration
• closure of the aortic valve is abnormally delayed so that A2 follows P2 in expiration
• normal inspiratory delay of P2 makes the split disappear
• most common cause = left bundle branch block

Question 7

Extra sounds in systole

Answer 7

• such as ejection sounds or systolic clicks

- note location, timing, intensity, pitch, and variations with respiration

Question 8

Extra sounds in diastole

Answer 8

• S3, S4, or an opening snap

- note location, timing, intensity, pitch, and variations with respiration

Question 9

Systolic and Diastolic murmurs

Answer 9

-differentiated from S1 and S2 and extra sounds by their long duration

Question 10

Potential Causes of Systolic Murmurs

Answer 10

• aortic stenosis
• aortic sclerosis
• innocent (benign) murmur
• hypertrophic cardiomyopathy
• ventral septal defect
• tricuspid regurgitation
• mitral valve prolapse
• mitral insufficiency

Question 11

Potential Causes of Diastolic Murmurs

Answer 11

• aortic insufficiency
• pulmonic regurgitation
• mitral stenosis
• tricuspid stenosis