Heart sounds and murmurs

Question 1

what causes an S1, S2, S3, S4 heart sounds?

Answer 1

S1 corresponds to AV valves closing (mitral, tricuspid)

S2 corresponds to pulmonic and aortic valve closing

S3 corresponds to rapid ventricular filling in early diastole - associated with high filling pressures (e.g. mitral regurgitation), common in dilated ventricals,

S4 occurs in late diastole - due to atrial kick, associated with high atrial pressure and often due to ventricular hypertrophy

Question 2

what does the a wave correspond to on the jugular venus pulse curve

Answer 2

atrial contraction - seen in late ventricular diastole

Question 3

what does the c wave correspond to on the jugular venus pulse curve

Answer 3

right ventricular contraction - tricupid valve is buldging into the atrium – increases pressure on venous system

Question 4

what does the v wave correspond to on the jugular venus pulse curve

Answer 4

increased atrial pressure due to filling against closed tricupid valve – leading up to the opening of the AV valves (mitral and tricupid)

Question 5

what venus pulse wave occurs at a similar time as the S4 heart sound?

Answer 5

a wave - during atrial contraction

Question 6

what abnormaltiy of the jugular venous pulse is expected in a patient with atrial fibrillation?

Answer 6

absent a wave

Question 7

which EKG segment is associated with the AV valve closure?

Answer 7

QRS - ventricular contraction

immediately precedes S1

Question 8

when does normal splitting occur? What causes this?

Answer 8

aortic valve closes slightly before pulmonic valve

on inspiration the increase in venous return to the right atrium causes an increase in preload to the right ventrical, which then takes slightly longer to pump out larger volume of blood. As a consequence the pulmonic valve takes slightly longer to close.

on expiration the slitting (time between aortic and pulmonic valve closure) is shorter

Question 9

when would wide splitting occur? how would this be affected by inspiration vs expiration

Answer 9

conditions in which there is delayed right ventricular emptying (e.g. pulmonic stenosis or right bundle branch block)

wide splitting is exaggerated on inspiration due to even larger right ventricular preload more blood to pump out before pulmonic valve can close

Question 10

when does fixed splitting occur?

Answer 10

atrial septal defects

left to right shunt leads to increased right atrial and right ventricular volumes which increases flow through the pulmonic valve - so much additional flow is taking place due to the shunt that regardless of breath, pulmonic closure is greatly delayed

Question 11

what is paradoxical splitting and when does it occur?

Answer 11

paradoxical splitting is when pulmonic valve closure takes place before aortic valve closure

heard in conditions that have delayed aortic valve closure (e.g. aortic stenosis or left bundle branch block)

heart more on expiration