8.1.1 Outline the physiologic mechanisms common

to ventricular pacemakers.

8.1.2 Describe the expected path of conduction for

an impulse originating in the ventricles.

8.1.3 Identify EKG features common to all

arrhythmias in the ventricular category.

8.2 Outline the identifying features specific to each of

the arrhythmias originating in the ventricles.

8.2.1 Describe Premature Ventricular Complexes,

including etiology, conduction, and resulting

EKG features (regularity, rate, P waves, PR

intervals, and QRS complexes).

8.2.2 Describe Ventricular Tachycardia, including

etiology, conduction, and resulting EKG

features (regularity, rate, P waves, PR

intervals, and QRS complexes).

8.2.3 Describe Ventricular Fibrillation, including

etiology, conduction, and resulting EKG

features (regularity, rate, P waves, PR

intervals, and QRS complexes).

8.2.4 Describe Idioventricular Rhythm, including

etiology, conduction, and resulting EKG

features (regularity, rate, P waves, PR

intervals, and QRS complexes).

8.2.5 Describe Asystole, including etiology,

conduction, and resulting EKG features

(regularity, rate, P waves, PR intervals, and

QRS complexes).

Section II: Practice Strips

Chapter 9 PRACTICE MAKES PERFECT

9 Identify basic cardiac arrhythmias as presented on

6-second rhythm strips.

9.1 Apply techniques learned in Chapters 1–8 to

analyze each of the rhythm strips in Chapter 9.

9.1.1 Use a methodical process to approach data

collection (regularity, rate, P waves, PR

intervals, and QRS complexes).

9.1.2 Analyze collected data and apply it to rules

of each arrhythmia to identify the presenting

arrhythmia.

Chapter 10 FINAL CHALLENGE

10 Test yourself on your ability to identify basic cardiac

arrhythmias as presented on 6-second rhythm strips.

10.1 Apply techniques learned in Chapters 1–8 to

analyze each of the rhythm strips in Chapter 10.

10.1.1 Use a methodical process to approach data

collection (regularity, rate, P waves, PR

intervals, and QRS complexes).

10.1.2 Analyze collected data and apply it to

rules of each arrhythmia to identify the

presenting arrhythmia.

10.2 Demonstrate your competency by approaching

all 100 strips in a self-test format, without

referring to outside resources.

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xvi Learning Objectives

Section III: Appendices

Appendix A CARDIAC ANATOMY AND

PHYSIOLOGY

A.1 Describe the heart’s location and structure.

A.2 Identify the four internal chambers of the heart.

A.3 Describe the heart walls and the pericardial sac.

A.3.1 Name the walls between the heart’s chambers.

A.3.2 Describe the three layers of the heart wall.

A.3.3 Differentiate between left and right heart

pumping functions.

A.3.4 Describe the pumping activity in a single

cardiac cycle.

A.4 Explain the heart’s valves.

A.4.1 Name the four valves.

A.4.2 Explain the valves’ role in the heart’s pumping

cycle.

A.5 Identify the four heart sounds.

A.5.1 Explain the first and second heart sounds.

A.5.2 Explain the third and fourth heart sounds.

A.5.3 Explain gallop rhythms.

A.5.4 Explain heart murmurs.

A.6 Explain systole and diastole.

A.6.1 Describe atrial diastole and systole.

A.6.2 Describe ventricular diastole and systole.

A.7 Explain coronary circulation.

A.7.1 State the purpose of coronary circulation.

A.7.2 Describe the functions of the coronary arteries,

cardiac veins, and coronary sinus.

A.8 Identify the heart’s surfaces.

Appendix B PATHOPHYSIOLOGY

AND CLINICAL IMPLICATIONS OF

ARRHYTHMIAS

B.1 Describe the clinical effects of arrhythmias.

B.1.1 Define cardiac output.

B.1.2 Give the formula for a calculated cardiac

output.

B.1.3 Name three categories of arrhythmia that can

interfere with cardiac output.

B.1.4 List eight symptoms of reduced cardiac output.

B.2 Explain the general principles of treating

arrhythmias.

B.2.1 Name additional measures that may be

needed to support perfusion.

B.2.2 Explain the role of the American Heart

Association in developing and maintaining

Advanced Cardiac Life Support

recommendations for treating arrhythmias.

B.3 Explain the significance of each of the 22 basic

arrhythmias in this book, and describe the clinical

picture of each.

Appendix C 12-LEAD

ELECTROCARDIOGRAPHY

C.1 Explain the advantage of a 12-lead EKG tracing.

C.2 State the fundamental rules of electrocardiography.

C.3 Explain leads and electrode placement.

C.3.1 Differentiate between bipolar and unipolar

leads.

C.3.2 Define monitoring lead.

C.3.3 Describe the placement of leads on the frontal

and horizontal planes.

C.4 Explain the vectors and axis of electrical flow

through the heart.

C.4.1 Define mean QRS axis.

C.4.2 Explain lead axes.

C.4.3 Explain the EKG features of R waves,

Q waves, S waves, QS waves, Intrinsicoid

Deflections, J Points, and QT Intervals.

C.4.4 Explain vector relationships.

C.4.5 Describe axis deviation and give the

significance of left and right axis deviation.

C.4.6 Describe a method for quickly estimating

QRS axis.

C.5 Describe the standardized format for a printed

12-lead EKG report.

C.5.1 Explain the importance of learning to

recognize normal in 12-lead EKGs.

C.6 State the limitations of 12-lead EKGs.

Appendix D BASIC 12-LEAD

INTERPRETATION

D.1 Explain interpreting myocardial damage on the

EKG.

D.1.1 Define ischemia.

D.1.2 Define myocardial infarction.

D.1.3 Describe EKG changes associated with

myocardial damage.

D.1.4 Describe the evolution of ischemic changes

(age of infarction).

D.1.5 State which leads identify damage on specific

surfaces of the heart.

D.2 Explain interpreting chamber enlargement on the

EKG.

D.2.1 State causes of chamber enlargement.

D.2.2 Describe the appearance of chamber

enlargement on the EKG.

Learning Objectives xvii

D.3 Explain interpreting bundle branch block on the

EKG.

D.3.1 Define bundle branch block.

D.3.2 Describe the appearance of bundle branch

block on the EKG.

D.3.3 Differentiate between right and left bundle

branch block on the EKG.

D.4 Explain interpreting other abnormalities on the EKG.

D.4.1 Describe the appearance of pericarditis on the

EKG.

D.4.2 Describe the appearance of digitalis toxicity on

the EKG.

D.4.3 Describe the appearance of hyperkalemia and

hypokalemia on the EKG.

D.4.4 Describe the appearance of hypercalcemia and

hypocalcemia on the EKG.

D.5 Explain the format for analyzing a 12-lead EKG.

D.5.1 Explain the importance of a methodical

approach to analysis.

D.5.2 Name the subjects that the summary analysis

of an EKG should address.

Appendix E PACEMAKERS

E.1 Describe pacemakers.

E.1.1 Explain the purpose of artificial pacemakers.

E.1.2 Define capture.

E.1.3 Name the three components of pacemakers.

E.2 Name the chambers of the heart that a pacemaker

may pace.

E.3 Describe a “smart” pacemaker.

E.4 Explain the two basic ways in which pacemakers can

initiate impulses.

E.4.1 Define triggered pacemaker.

E.4.2 Define inhibited pacemaker.

E.5 Explain the three-letter code system used to classify

pacemakers.

E.6 Explain assessment of pacemaker function.

E.6.1 Describe the appearance of pacemakers on the

EKG.

E.6.2 Describe the basic sequence of assessing

pacemaker function.

E.6.3 Name the information that can be revealed by

the relationship between pacemaker spikes

and the patient’s complexes.

E.7 Name and describe four common types of

pacemaker malfunctions.

E.8 Explain how pacemaker malfunction is treated.

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1

Overview

IN THIS CHAPTER, you’ll learn how cardiac arrhythmias reflect what is actually happening

electrically in the heart. You will explore the uses and limitations of cardiac arrhythmia monitoring.

You will learn how cardiac impulses are formed and how the heart’s electrical system conducts

electrical impulses throughout the heart. You will also learn how the nervous system can influence

the rate at which the heart forms electrical impulses.

Electrical vs. Mechanical Function

1. The human heart is intended to pump blood to the rest of the body. This process has

two distinct components:

• The electrical impulse that tells the heart to beat

• The mechanical beating of the heart in response to the electrical stimulation, resulting in pumping of blood

To perform these two functions, the heart has two distinct types of cells. There are

electrical (conductive) cells, which initiate electrical activity and conduct it through

the heart, and there are mechanical (contracting) cells, which respond to the electrical

stimulus and contract to pump blood. After the cells initiate

Electrophysiology

1

electrical

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2 Chapter 1

the impulse and conduct it through the heart, the cells respond

by contracting and pumping blood.

2. The heart will respond with contraction only if it is stimulated by electrical activity. Thus,

you cannot have a mechanical response if there is no stimulus.

3. After the electrical cells have discharged their stimuli, the mechanical cells are

expected to respond by .

4. Without stimulus, the mechanical cells can’t be expected

to contract.

5. Since it is not practical to see inside a living patient’s heart, we must rely on

external evidence to evaluate the status of both electrical and mechanical cardiac function. For a complete assessment of cardiac status, we must evaluate both

 and functions.

6. As part of our assessment of mechanical function, we use blood pressure, pulses,

and other perfusion parameters to determine whether the heart is pumping adequately. We must also look for external evidence to evaluate the heart’s electrical activity. The best way to do this is to monitor the electrocardiogram (EKG). An

EKG tracing is used to evaluate the activity of the heart,

while the mechanical activity is evaluated by assessing and

 .