Cardio - Physio (Cardiac cycle & Splitting)

Question 1

What are the phases of the cardiac cycle (as it applies to the left ventricle)?

Answer 1

(1) Isovolumetric contraction (2) Systolic ejection (3) Isovolumetric relaxation (4) Rapid filling (5) Reduced filling

Question 2

When is Isovolumetric contraction in the cardiac cycle?

Answer 2

Period between mitral valve closure and aortic valve opening

Question 3

When is Systolic ejection in the cardiac cycle?

Answer 3

Period between aortic valve opening and closing

Question 4

When is Isovolumetric relaxation in the cardiac cycle?

Answer 4

Period between aortic valve closing and mitral valve opening

Question 5

When is Rapid filling in the cardiac cycle?

Answer 5

Period just after mitral valve opening

Question 6

When is Reduced filling in the cardiac cycle?

Answer 6

Period just before mitral valve closure

Question 7

Graph the cardiac cycle phases, labeling key phases as well as the Stroke Volume, End Diastolic Volume, and End Systolic Volume.

Answer 7

See p. 256 in First Aid - top graph, dark blue tracing

Question 8

After having graphed the normal cardiac cycle phases, draw the changes created by Increasing Preload and SV.

Answer 8

See p. 256 in First Aid - top graph, light green tracing

Question 9

After having graphed the normal cardiac cycle phases, draw the changes created by Increasing Afterload, Aortic Pressure and End Systolic Volume and Decreasing Stroke Volume.

Answer 9

See p. 256 in First Aid - top graph, light blue tracing

Question 10

After having graphed the normal cardiac cycle phases, draw the changes created by Increasing Contractility, Stroke Volume, and Ejection Fraction and Decreasing End Systolic Volume.

Answer 10

See p. 256 in First Aid - top graph, orange tracing

Question 11

At what phase in the cardiac cycle does the highest O2 consumption occur?

Answer 11

Isovolumetric contraction (i.e., Period between mitral valve closure and aortic valve opening)

Question 12

What effect(s) does Increased Preload have in the cardiac cycle?

Answer 12

(= Increased End Diastolic Volume) Increased Stroke Volume

Question 13

What effect(s) do Increased Afterload and Aortic pressure have in the cardiac cycle?

Answer 13

Decreased Stroke Volume & Increased End Systolic Volume

Question 14

What effect(s) do Increased Contractility and Ejection Fraction have in the cardiac cycle?

Answer 14

Increased Stroke Volume & Decreased End Systolic Volume

Question 15

What are the names of the sounds that can be heard in the cardiac cycle?

Answer 15

S1, S2, S3, S4 (“atrial kick”)

Question 16

What is S1? Where is it loudest?

Answer 16

Mitral and tricupsid valve closure; Loudest at mitral area

Question 17

What is S2? Where is it loudest?

Answer 17

Aortic and pulmonary valve closure; Loudest at left sternal border

Question 18

When can S3 be heard? With what is it associated?

Answer 18

In early diastole during rapid ventricular filling phase; Associated with increased filling pressures (e.g., mitral regurgitation, CHF)

Question 19

In what circumstances is S3 more common? When is S3 normal?

Answer 19

More common in dilated ventricles (but normal in children and pregnancy women)

Question 20

When can S4 be heard? What causes S4? With what is it associated, and why?

Answer 20

In late diastole; High atrial pressure; Associated with ventricular hypertrophy, because left atrium must push against stiff LV wall

Question 21

What are the names of the parts of the jugular venous pulse (JVP)?

Answer 21

(1) a wave (2) c wave (3) x descent (4) v wave (5) y descent

Question 22

What is the a wave of JVP?

Answer 22

Atrial contraction; Think: “a = Atrial (contraction)”

Question 23

What is the c wave of JVP?

Answer 23

RV contraction (closed tricuspid valve bulging into atrium); Think: “c = (RV) Contraction”

Question 24

What is the x descent of JVP?

Answer 24

Atrial relaxation and downward displacement of closed tricuspid valve during ventricular contraction

Question 25

What is the v wave of JVP?

Answer 25

Increased right atrial pressure due to filling against closed tricuspid valve; Think: “v = valve”

Question 26

What is the y descent of JVP?

Answer 26

blood flow from RA to RV

Question 27

Graph JVP.

Answer 27

See Pg. 256 - bottom graph

Question 28

Graph heart sounds.

Answer 28

See Pg. 256 - bottom graph

Question 29

Given that you’ve graphed JVP and heart sounds, add in the following to the graph: (1) Left ventricular pressure (2) Aortic pressure (3) Ventricular volume (4) ECG.

Answer 29

See Pg. 256 - bottom graph

Question 30

On the graph of JVP, heart sounds, left ventricular pressure, Aortic pressure, Ventricular volume, and ECG, label the following time periods: (1) Atrial systole (2) Isovolumetric contraction (3) Rapid ejection (4) Reduced ejection (5) Systole (6) Isovolumentric relaxation (7) Rapid ventricular filling (8) Reduced ventricular filling.

Answer 30

See Pg. 256 - bottom graph

Question 31

What is normal splitting? What primarily causes it? What is a contributing factor to it?

Answer 31

Upon inspiration, delayed closure of pulmonic valve (i.e., split S2, with A2 first and P2 delayed); Inspiration –> drop in intrathoracic pressure –> increased in venous return to the RV –> increased RV stroke volume –> increased RV ejection time –> delayed closure of pulmonary valve; Decreased pulmonary impedance (i.e., increased capacity of the pulmonary circulation) also occurs during inspiration, which contributes to the delayed closure of pulmonic valve

Question 32

What is wide splitting? What causes it? In what kind of conditions is it seen? Give examples of such conditions.

Answer 32

Exaggeration of normal splitting = delayed pulmonic sound (regardless of breath, although inspiration seems to be a bit more delayed than expiration), due to delay in RV emptying; Seen in conditions that delay RV emptying (e.g., pulmonic stenosis, right bundle branch block)

Question 33

What is a key difference between normal versus wide splitting?

Answer 33

NORMAL - P2 delayed only on inspiration; WIDE = exaggeration of normal splitting = P2 delayed regardless of breath (but more so upon inspiration than expiration)

Question 34

What is fixed splitting? In what condition is fixed splitting seen, and why?

Answer 34

P2 greatly delayed to the same point on both inspiration and expiration; Seen in ASD; ASD –> left-to-right shunt –> Increased RA and RV volumes –> Increased flow through pulmonic valve such that, regardless of breath, pulmonic closure is greatly delayed;

Question 35

What is paradoxical splitting? In what kind of conditions is it seen? Give examples of such conditions.

Answer 35

Normal order of valve closure reversed so that P2 sound occurs before delayed A2 sound… therefore on inspiration, P2 closes later and moves closer to A2, thereby “paradoxically” eliminating the split; Seen in conditions that delay LV emptying (e.g., aortic stenosis, left bundle branch block).