RAD 113 Ch. 16 Study Guide

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Basic Cardiac Monitoring: The Electrocardiogram
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1

Process of depolarization and repolarization of the cardiac membrane.

Action potential

2

Irregularity of cardiac actions associated with physiologic or pathologic interruption of the neuroconductive tissues of the heart.

Abnormality within neural conduction system that adversely affect cardiac output.

Arrhythmia

3

No evidence of any cardiac neuroconductive activity (full cardiac arrest).

Asystole

4

Cardiac cell membranes spontaneously depolarize at recurrent periods. This process is unique to the tissue of the cardiac neural conduction system.

Automaticity

5

Slowness of heartbeat. Pulse rate slows to less than 60 beats per minute.

Bradycardia

6

Events that occur from the beginning of one ventricular contraction (systole) until the beginning of another.

Cardiac cycle

7

Amount of blood ejected from the ventricles each minute; calculated as the product of stroke volume times heart rate.

Is the vital event necessary to maintain blood flow.

Cardiac output

8

Myocardial cells are stimulated to contract. When cell is stimulated, movement of ions in and out of the membrane alters its charge, reversing the resting potential.

Depolarization

9

Quivering contraction of cardiac muscle fibers.

Fibrillation

10

Myocardial muscle cells relax. Reversal of ion flow that reestablishes a positive charge to the outside of the membrane.

Repolarization

11

Heart rate above 100 beats per minute.

Tachycardia

12

Steps that summarize the action potential sequence.

  1. Resting cell membrane is charged positively on outside and negatively on inside
  2. After stimulation, positive ions enter cell, reversing this polarity
  3. Continues until entire cell membrane is depolarized
  4. Ions return to normal location, cell repolarizes to its normal resting potential
13

Observed in an electrocardiograms (ECG) tracing is the action potentials of __________.

  1. Atrial muscle cells
  2. Ventricular muscle cells
14

The electrical sequence of a cardiac cycle is initiated by the sinoatrial node, known as the _________.

Pacemaker

15

The baseline of an ECG (called isoelectric line) signifies __________.

Resting membrane potentials

16

The positive or negative changes in the ECG tracing relative to the isocenter over the time of the cycle.

(Lettered in alphabetical order)

Deflections

17

Depolarization of atrial muscle cells. First deflection.

P wave

18

Represents depolarization of ventricular muscle cells.

QRS complex

19

What does each portion of the QRS complex stand for?

  1. Q portion
  2. R portion
  3. S portion
  1. Q - initial downward deflection
  2. R - initial upward deflection
  3. S - return to baseline (isoelectric point)
20

Portion of QRS complex that is often not evident.

Q portion

21

Measured from beginning of P wave to the beginning of the R portion of the QRS complex.

PR interval

22

Repolarization of ventricular muscle.

T wave

23

Theorized to represent repolarization of the papillary muscles and Purkinje fibers. Typically small and when evident, follows the T wave.

U wave

24

The PR interval starts with __________ and ends with __________.

  1. Atrial muscle depolarization
  2. Start of ventricular depolarization
25

If PR interval is prolonged, the presence of a __________ can be deduced.

AV block

26

The eight physiologic events for a cardiac cycle.

  1. SA node initiates impulse (fires 60-80 times/minute)
  2. Depolarization of atrial muscle (P wave)
  3. Atrial contraction
  4. Depolarization of AV node and common bundle (fires 60-80 times/minute)
  5. Repolarization of atrial muscle
  6. Depolarization of ventricular muscle (QRS complex)
  7. Contraction of ventricular muscle
  8. Repolarization of ventricular muscle (T wave)
27

Number of physiologic events actually observed on an ECG tracing.

3

28

Physiologic events for a cardiac cycle not visible on an ECG tracing.

  1. SA node initiating impulse
  2. Atrial contraction
  3. Depolarization of AV node and common bundle
  4. Repolarization of atrial muscle
  5. Contraction of ventricular muscle
29

5-step analysis for ECG tracing.

  1. Is rhythm regular or irregular (If intervals between QRS complexes are consistent, ventricular rhythm is regular)
  2. Are QRS complexes similar, and are they narrow (duration of QRS complex should not exceed .12 seconds)
  3. Are all P waves similar, are PR intervals normal (Normal PR interval is 0.12 - 0.20 seconds)
  4. Is rate normal
  5. Do waves and complexes proceed in normal sequence
30

If QRS complexes are narrow, rhythm is being initiated by pacemaker at the AV node or higher and is described as a __________.

Supraventricular rhythm

31

If QRS complexes are wide, the pacemaker is in the ventricles and is described as a __________.

Ventricular rhythm

32

If QRS complexes vary in appearance, more than one pacemaker is generating impulses. This is referred to as __________.

Ectopic pacemakers

33

One of the most common cardiac arrhythmias.

Atrial fibrillation

34

Occasionally an extra impulse is fired from within the ventricle and creates a wide QRS complex. These complexes are called __________.

Premature ventricular contractions (PVCs)

35

Normal ECG waveform.

card image
36

Sinues Bradycardia. (Slow heart rate of approx. 47 beats/minute)

card image
37

Sinus tachycardia (High heart rate of approx. 140 beats/minute)

card image
38

Atrial fibrillation.

card image
39

Normal sinus rhythm with PVCs.

card image

There are 2 premature ventricular contractions (PVCs)

40

Ventricular tachycardia

card image
41

Heart rhythm that abnormally originates in the ventricles.

Ventricular tachycardia

42

When ventricular tachycardia lasts for a prolonged period of time (greater than 30 seconds) it is called __________ and requires treatment.

Sustained V-tach

43

Serious arrhythmia that is life-threatening. Instead of myocardial contraction, the muscle fibers twitch or quiver. This results in little to no blood being pumped and cardiac output is virtually zero. This is a case of cardiac arrest.

Ventricular fibrillation

44

Ventricular fibrillation.

card image
45

Asystole (full cardiac arrest).

card image
46

Arrhythmias are typically classified by origin of the abnormality or speed of resulting heart rate (Tachycardia/bradycardia).

The two origins of the abnormality are __________ and __________.

  1. Atria
  2. Ventricular
47

Tachycardias may involve the __________ or __________.

  1. Atria
  2. Ventricles
48

Bradycardia typically involves either __________ or __________ abnormalities.

  1. SA node
  2. AV node
49

Common treatments of arrhythmias.

  1. Antiarrhythmic medications
  2. Physical/invasive forms of therapy including cardiac surgery
  3. Implantable device
50

Implantable devices used for treating arrhythmias.

  1. Pacemaker
  2. Implantable cardioverter-defribrillator (ICD)
51

Used most often to treat bradycardia.

Pacemaker

52

Typically used to treat tachycardia and irregular cardiac contraction disorders involving the ventricles of the heart.

Implantable cardioverter-defribrillator (ICD)

53

Useful for treating atrial-related causes of arrhythmias, including atrial fibrillation. Involves external shock therapy to the chest to restore normal cardiac rhythm.

Cardioversion therapy

54

Type of therapy administered in severe cases of ventricular tachycardia or fibrillation.

Electric shock defibrillation therapy

55

Involve either heating or freezing tissues within a chamber of the heart that is considered to be cause of arrhythmia.

Ablation therapy

56

Most frequently performed type of ablation therapy. Involves use of electrodes at the tip of catheter wires that are heated with radiofrequency energy (High-frequency AC current).

Radiofrequency ablation (RFA)