1. Chapter 25 Assessment of Cardiovascular Function

2. Overview of Anatomy and Physiology
Three layers: endocardium, myocardium, epicardium
Four chambers: Right atrium and ventricle, left atrium and ventricle
Atrioventricular valves: tricuspid and mitral
Semilunar valves: aortic and pulmonic
Coronary arteries
Cardiac conduction system (electrophysiology)
Cardiac hemodynamics

3. Anatomy of the Heart
Figure 25-1

4. Greater Vessels, Heart Chambers and Pressures
Figure 25-2

5. Cardiac Conduction System: Electrophysiology
(60-100)
(40-60)
(30-40)
(30-40)
Figure 25-3

6. Question
Which of the following is the primary pacemaker for the myocardium?
Atrioventricular junction
Bundle of His
Purkinje fibers
Sinoatrial node

7. Answer Sinoatrial node
Rationale: The sinoatrial node is the primary pacemaker for the myocardium

8. Cardiac Action Potential
Depolarization: electrical activation of cell caused by influx of sodium into cell while potassium exits cell
Repolarization: return of cell to resting state caused by reentry of potassium into cell while sodium exits
Refractory periods
Effective refractory period: phase in which cells are incapable of depolarizing
Relative refractory period: phase in which cells require stronger-than-normal stimulus to depolarize

9. Cardiac Action Potential Cycle
Figure 25-4

10. Cardiac Cycle
Refers to the events that occur in the heart from the beginning of one heartbeat to the next
Number of cycles depends on heart rate
Each cycle has three major sequential events:
Diastole
Atrial systole
Ventricular systole

11. Cardiac Output
Stroke volume(SV): amount of blood ejected with each heartbeat
Preload: degree of stretch of cardiac muscle fibers at end of diastole
Afterload: resistance to ejection of blood from ventricle
Contractility: ability of cardiac muscle to shorten in response to electrical impulse

12. Cardiac Output (cont.)
Ejection fraction: percent of end diastolic volume ejected with each heart beat (left ventricle)
Cardiac output (CO): amount of blood pumped by ventricle in liters per minute
CO = SV × HR

13. Influencing Factors Control of heart rate
Autonomic nervous system, baroreceptors
Control of stroke volume
Preload: Frank–Starling Law
Afterload: affected by systemic vascular resistance, pulmonary vascular resistance

14. Contractility
Contractility increased by catecholamines, SNS, certain medications
Increased contractility results in increased stroke volume
Decreased by hypoxemia, acidosis, certain medications

15. Question Which of the following best defines stroke volume?
The amount of blood ejected with each heartbeat
Amount of blood pumped by the ventricle in liters per minute
Degree of stretch of the cardiac muscle fibers at the end of diastole
Ability of the cardiac muscle to shorten in response to an electrical impulse

16. Answer The amount of blood ejected with each heartbeat
Rationale: Stroke volume is the amount of blood ejected with each heartbeat. Cardiac output is the amount of blood pumped by the ventricle in liters per minute. Preload is the degree of stretch of the cardiac muscle fibers at the end of diastole. Contractility is the ability of the cardiac muscle to shorten in response to an electrical impulse

17. Assessment of the CV Health history Demographic information
Family/genetic history
Cultural/social factors
Risk factors
Modifiable
Nonmodifiable

18. Assessment of the CV System
Health history
Common symptoms
Chest pain/discomfort
Pain/discomfort in other areas of the upper body
SOB/dyspnea
Peripheral edema, wt gain, abd distention
Palpitations
Unusual fatigue, dizziness, syncope, change in LOC

19. Past Health, Family, and Social History
Medications
Nutrition
Elimination
Activity, exercise
Sleep, rest
Self-perception/self-concept
Roles and relationships
Coping and stress

20. Physical Assessment of CV System
General appearance
Skin and extremities
Pulse pressure
Blood pressure; orthostatic changes
Arterial pulses
Jugular venous pulsations
Heart inspection, palpation, auscultation
Assessment of other systems

21. Laboratory Tests Cardiac biomarkers
Blood chemistry, hematology, coagulation
Lipid profile
Brain (B-type) natriuretic peptide
C-reactive protein
Homocysteine
Refer to Table 25-4

22. Electrocardiography 12-lead ECG Continuous monitoring Hardwire
Telemetry
Lead systems
Ambulatory monitoring

23. Cardiac Stress Testing
Exercise stress test
Pt walks on treadmill with intensity progressing according to protocols
ECG, V/S, symptoms monitored
Terminated when target HR is achieved
Pharmacologic stress testing
Vasodilating agents given to mimic exercise

24. Diagnostic Tests Radionuclide imaging: Myocardial perfusion imaging
Positron emission tomography
Test of ventricular function, wall motion
Computed tomography
Magnetic resonance angiography

25. Echocardiography Noninvasive ultrasound test that is used to:
Measure the ejection fraction
Examine the size, shape, and motion of cardiac structures
Transthoracic
Transesophageal

26. Cardiac Catheterization
Invasive procedure used to diagnose structural and functional diseases of the heart and great vessels
Right Heart Cath
Pulmonary artery pressure and oxygen saturations may be obtained; biopsy of myocardial tissue may be obtained
Left Heart Cath
Involves use of contrast agent

27. Nursing Interventions-Cardiac Cath
Observe cath site for bleeding, hematoma
Assess peripheral pulses
Evaluate temp, color, and cap refill of affected extremity
Screen for dysrhythmias
Maintain bed rest 2 to 6 hours
Instruct patient to report chest pain, bleeding
Monitor for contrast-induced nephropathy
Ensure patient safety

28. Hemodynamic Monitoring
Central venous pressure
Pulmonary artery pressure
Intra-arterial B/P monitoring
Minimally invasive cardiac output monitoring devices

29. Pulmonary Artery Catheter and Pressure Monitoring System
Figure 25-12