chapter 026

Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 26

Assessment of Cardiovascular Function

Chapter 26

Assessment of Cardiovascular Function


Overview of Anatomy and Physiology - HeartOverview of Anatomy and Physiology - Heart

• Three layers

– Endocardium

– Myocardium

– Epicardium

• Four chambers

• Heart valves


Overview of Anatomy and Physiology – Heart (cont’d)Overview of Anatomy and Physiology – Heart (cont’d)

• Coronary arteries

• Cardiac conduction system

• Cardiac hemodynamics


Structure of the HeartStructure of the Heart


Cardiac Conduction SystemCardiac Conduction System


Terms - Cardiac Action Potential Terms - 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 re-entry 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


Cardiac Action PotentialCardiac Action Potential


Great Vessel and Heart Chamber PressuresGreat Vessel and Heart Chamber Pressures


Terms - Cardiac OutputTerms - Cardiac Output

• Stroke volume: amount of blood ejected with each heartbeat

• Cardiac output: amount of blood pumped by ventricle in liters per minute

• Preload: degree of stretch of cardiac muscle fibers at end of diastole

• Contractility: ability of cardiac muscle to shorten in response to electrical impulse


Terms - Cardiac Output (cont’d)Terms - Cardiac Output (cont’d)

• After load: resistance to ejection of blood from ventricle

• Ejection fraction: percent of end diastolic volume ejected with each heart beat


CO = SV x HRCO = SV x HR• Control of heart rate

– Autonomic nervous system, baroreceptors

• Control of strike volume

– Preload: Frank-Starling Law

– After load: affected by systemic vascular resistance, pulmonary vascular resistance

– Contractility increased by catecholamines, SNS, some medications

• Decreased by hypoxemia, acidosis, some medications


QuestionQuestion

• Which of the following is the normal pacemaker for the myocardium?

A.Atrioventricular junction

B.Bundle of His

C.Purkinje fibers

D.Sinoatrial node


AnswerAnswer

• D. Sinoatrial node

• Rationale: The sinoatrial node is the normal pacemaker for the myocardium.


QuestionQuestion

• Which of the following best defines stroke volume?

A.The amount of blood ejected with each heartbeat

B.Amount of blood pumped by the ventricle in liters per minute

C.Degree of stretch of the cardiac muscle fibers at the end of diastole

D.Ability of the cardiac muscle to shorten in response to an electrical impulse


AnswerAnswer

• A. 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.


AssessmentAssessment

• Health history

– Demographic information

– Family/genetic history

– Cultural/social factors

• Risk factors

– Modifiable

– Nonmodifiable


Most Common Clinical ManifestationsMost Common Clinical Manifestations

• Chest pain

• Dyspnea

• Peripheral edema, weight gain

• Fatigue

• Dizziness, syncope, changes in level of consciousness


AssessmentAssessment

• Medications

• Nutrition

• Elimination

• Activity, exercise

• Sleep, rest

• Self-perception, self-concept

• Roles, relationships

• Sexuality, reproduction

• Coping, stress tolerance

• Prevention strategies


Health Promotion, Perception, and Management QuestionsHealth Promotion, Perception, and Management Questions

• Ask regarding health promotion, preventive practices

– What type of health issues do you have? Are you able to identify any family history or behaviors that put you at risk of this health problem?

– What are your risk factors for heart disease? What do you do to stay healthy?

– How is your health? Have you noticed any changes?


Health Promotion, Perception, and Management Questions (cont’d)Health Promotion, Perception, and Management Questions (cont’d)

• Ask regarding health promotion, preventive practices

– Do you have a cardiologist or primary health care provider? How often do you go for check-ups?

– Do you use tobacco or alcohol?

– What medications do you take?


QuestionQuestion

• Where does the nurse auscultate the apex of the heart?

A.Erb’s point

B.Fifth intercoastal space

C.Pulmonic area

D.Tricuspid area


AnswerAnswer

• B. Fifth intercoastal space

• Rationale: The nurse auscultates the apex of the heart at the fifth intercoastal space.


Laboratory TestsLaboratory Tests

• Cardiac biomarkers

• CK, CK-MB

• Myoglobin

• Troponin T and I

• Lipid profile

• Brain (B-type) natriuretic peptide

• C-reactive protein

• Homocysteine


ElectrocardiographyElectrocardiography

• 12 lead ECG

• Continuous monitoring: hardwire, telemetry

• Signal-averaged electrocardiogram

• Continuous ambulatory monitoring

• Transtelephonic monitoring

• Wireless mobile monitoring


Electrocardiography (cont’d)Electrocardiography (cont’d)

• Cardiac stress testing

– Exercise stress testing

– Pharmacologic stress testing


Diagnostic TestsDiagnostic Tests

• Radionuclide imaging

– Myocardial perfusion imaging

– Test of ventricular function, wall motion

– Computed tomography

– Positron emission tomography

– Magnetic resonance angiography


Cardiac CatherizationCardiac Catherization

• Invasive procedure study used to measure cardiac chamber pressures, assess patency of coronary arteries

• Requires ECG, hemodynamic monitoring; emergency equipment must be available

• Assessment prior to test; allergies, blood work

• Assessment of patient postprocedure; circulation, potential for bleeding, potential for dysrhythmias

• Activity restrictions

• Patient education pre-, postprocedure


Hemodynamic MonitoringHemodynamic Monitoring

• CVP

• Pulmonary artery pressure

• Intra-arterial BP monitoring


Phlebostatic LevelPhlebostatic Level


Pulmonary Artery CatheterPulmonary Artery Catheter

• Refer to fig. 26-11


Pulmonary Artery Catheter and Pressure Monitoring SystemPulmonary Artery Catheter and Pressure Monitoring System

chapter 026

Documents