Cardio - Physio (Cardiac cycle & Splitting) Flashcards
See p. 270-271 in First Aid 2014 or p. 256-257 in First Aid 2013 Sections include: -Cardiac cycle -Splitting
What are the phases of the cardiac cycle (as it applies to the left ventricle)?
(1) Isovolumetric contraction (2) Systolic ejection (3) Isovolumetric relaxation (4) Rapid filling (5) Reduced filling
When is Isovolumetric contraction in the cardiac cycle?
Period between mitral valve closure and aortic valve opening
When is Systolic ejection in the cardiac cycle?
Period between aortic valve opening and closing
When is Isovolumetric relaxation in the cardiac cycle?
Period between aortic valve closing and mitral valve opening
When is Rapid filling in the cardiac cycle?
Period just after mitral valve opening
When is Reduced filling in the cardiac cycle?
Period just before mitral valve closure
Graph the cardiac cycle phases, labeling key phases as well as the Stroke Volume, End Diastolic Volume, and End Systolic Volume.
See p. 256 in First Aid - top graph, dark blue tracing
After having graphed the normal cardiac cycle phases, draw the changes created by Increasing Preload and SV.
See p. 256 in First Aid - top graph, light green tracing
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.
See p. 256 in First Aid - top graph, light blue tracing
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.
See p. 256 in First Aid - top graph, orange tracing
At what phase in the cardiac cycle does the highest O2 consumption occur?
Isovolumetric contraction (i.e., Period between mitral valve closure and aortic valve opening)
What effect(s) does Increased Preload have in the cardiac cycle?
(= Increased End Diastolic Volume) Increased Stroke Volume
What effect(s) do Increased Afterload and Aortic pressure have in the cardiac cycle?
Decreased Stroke Volume & Increased End Systolic Volume
What effect(s) do Increased Contractility and Ejection Fraction have in the cardiac cycle?
Increased Stroke Volume & Decreased End Systolic Volume
What are the names of the sounds that can be heard in the cardiac cycle?
S1, S2, S3, S4 (“atrial kick”)
What is S1? Where is it loudest?
Mitral and tricupsid valve closure; Loudest at mitral area
What is S2? Where is it loudest?
Aortic and pulmonary valve closure; Loudest at left sternal border
When can S3 be heard? With what is it associated?
In early diastole during rapid ventricular filling phase; Associated with increased filling pressures (e.g., mitral regurgitation, CHF)
In what circumstances is S3 more common? When is S3 normal?
More common in dilated ventricles (but normal in children and pregnancy women)
When can S4 be heard? What causes S4? With what is it associated, and why?
In late diastole; High atrial pressure; Associated with ventricular hypertrophy, because left atrium must push against stiff LV wall
What are the names of the parts of the jugular venous pulse (JVP)?
(1) a wave (2) c wave (3) x descent (4) v wave (5) y descent
What is the a wave of JVP?
Atrial contraction; Think: “a = Atrial (contraction)”
What is the c wave of JVP?
RV contraction (closed tricuspid valve bulging into atrium); Think: “c = (RV) Contraction”
What is the x descent of JVP?
Atrial relaxation and downward displacement of closed tricuspid valve during ventricular contraction
What is the v wave of JVP?
Increased right atrial pressure due to filling against closed tricuspid valve; Think: “v = valve”
What is the y descent of JVP?
blood flow from RA to RV
Graph JVP.
See Pg. 256 - bottom graph
Graph heart sounds.
See Pg. 256 - bottom graph
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.
See Pg. 256 - bottom graph
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.
See Pg. 256 - bottom graph
What is normal splitting? What primarily causes it? What is a contributing factor to it?
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
What is wide splitting? What causes it? In what kind of conditions is it seen? Give examples of such conditions.
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)
What is a key difference between normal versus wide splitting?
NORMAL - P2 delayed only on inspiration; WIDE = exaggeration of normal splitting = P2 delayed regardless of breath (but more so upon inspiration than expiration)
What is fixed splitting? In what condition is fixed splitting seen, and why?
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;
What is paradoxical splitting? In what kind of conditions is it seen? Give examples of such conditions.
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).
