Rapid Interpretations of EKGs - Chapter 5 highlights

Question 1

What does arrhythmia mean?

Answer 1

abnormal rhythm

Question 2

Sinus arrhythmia represents normal, minimal variations in the SA Node’s pacing rate in association with what?

Answer 2

respirations

Question 3

What are the three conduction pathways that travel from the SA Node to the AV Node?

Answer 3

anterior internodal tract

middle internodal tract

posterior internodal tract

Question 4

What bundle branches off the SA Node and distributes depolarization to the left atrium?

Answer 4

Bachmann’s Bundle

Question 5

Ventricular depolarization begins midway down the interventricular septum, where which bundle branch produces fine terminal filaments?

Answer 5

the Left Bundle Branch (the Right Bundle Branch does not produce terminal filaments in the septum. so left-to-right depolarization of the septum occurs)

Question 6

The final phase of Purkinje repolarization may record as a small hump after the T wave, called what?

Answer 6

the U wave

Question 7

In some hearts with structural pathology or hypoxia, malfunctioning automaticity foci may suffer from “entrance block”, whereby any incoming depolarization is blocked, “protecting” them from passive depolarization by any other source. What is another name for entrance block?

Answer 7

parasystole

(when an automaticity focus has entrance block, it is said to be parasystolic. they will pace, but can’t be overdrive-suppressed)

Question 8

What does P’ stand for?

Answer 8

P’ (pronounced “P prime”) represents atrial depolarization by an automaticity focus, as opposed to normal Sinus-paced P waves

Question 9

Arrhythmias can be broken down into 4 categories. What are these categories?

Answer 9

irregular rhythms

escape

premature beats

tachyarrhythmias

Question 10

What are the 3 irregular atrial rhythms?

Answer 10

wandering pacemaker

multifocal atrial tachycardia

atrial fibrillation

Question 11

What are the three characteristics of wandering pacemaker?

Answer 11

Question 12

What are the three characteristics of multifocal atrial tachycardia?

Answer 12

MAT is an arrhythmia of patients who are very ill with COPD. The atrial automaticity foci are also ill, showing early signs of parasystole (entrance block) by developing a resistance to overdrive-suppression.

Question 13

What are the two characteristics of atrial fibrillation?

Answer 13

A-fib is NOT an arrhythmia of healthy, young individuals. It is the result of multiple “irritable” atrial foci, suffering from entrance block, pacing rapidly. These multiple atrial foci are parasystolic, so they’re insensitive to overdrive-suppression; therefore, they all pace at once.

Question 14

Define escape rhythm and escape beat?

Answer 14

Question 15

When would an Atrial Escape Rhythm occur?

Answer 15

With Sinus Arrest an atrial focus quickly escapes overdrive-suppression to become the dominant pacemaker at its inherent rate.

Question 16

When would a Junctional Escape Rhythm occur?

Answer 16

Absent regular pacing stimuli from above, an automaticity focus in the AV Junction may escape overdrive-suppression to become an active pacemaker producing a Junctional Escape Rhythm at its inherent rate.

Question 17

Because each Junctional automaticity focus is located within the AV Node, each pacing stimulus originating there will conduct to the ventricles as expected, but the paced stimuli may also depolarize the atria from below, producing what type of P waves in the EKG?

Answer 17

inverted P’ waves (may also be seen as: retrograde (inverted) P’ wave immediately before each QRS retrograde (inverted) P’ wave after each QRS retrograde (inverted) P’ wave buried within each QRS)

Question 18

When would a Ventricular Escape Rhythm occur?

Answer 18

When a ventricular automaticity focus is not regularly stimulated by paced depolarizations from above, so it escapes overdrive-suppression to emerge as the ventricular pacemaker.

Question 19

Ventricular Escape Rhythm usually results from one of what two mechanisms?

Answer 19

1. with complete conduction block high in the ventricular conduction system
2. total failure of the SA Node and all automaticity foci above the ventricles (aka “downward displacement of the pacemaker)

Question 20

Pacing from a ventricular focus is often so slow that blood flow to the brain is significantly reduced to the point of unconsciousness (syncope). What is this syndrome called?

Answer 20

Stokes-Adams Syndrome

(ask rudy about a funny syncope story about one of his patients)

Question 21

What is another name for Ventricular Escape Rhythm?

Answer 21

idioventricular rhythm

(should this accelerate above the inherent range, it becomes Accelerated Idioventricular Rhythm)

Question 22

Cardiac parasympathetic innervation inhibits the SA Node and also inhibits the ______ and ________ foci, but not the _________ foci. (choices: atrial, junctional, ventricular)

Answer 22

inhibits the atrial and junctional foci

does NOT inhibit the ventricular foci

(a burst of excessive parasympathetic activity depresses the SA Node (producing a pause) and also depresses the atrial and junctional foci, leaving only the ventricular foci to respond to the pause)

Question 23

What are the three types of premature beats?

Answer 23

Question 24

What are some causes of atrial and junctional foci irritability?

Answer 24

Question 25

What is meant by aberrant ventricular conduction?

Answer 25

Question 26

What are some causes of ventricular foci irritability?

Answer 26

Question 27

How many Premature Ventricular Contractions (PVCs) in one minute is considered pathological?

Answer 27

6 or more in one minute

Question 28

If PVCs all look the same, they are called?

Answer 28

unifocal PVCs (they originate from the same irritable ventricular foci)

Question 29

A run of 3 or more PVCs in rapid succession is really of a run of what?

Answer 29

Ventricular Tachycardia (VT)

Question 30

If a run of VT lasts longer than 30 seconds, what is is called?

Answer 30

sustained VT

Question 31

If each PVC looks different each time, then it is called what?

Answer 31

multifocal PVCs

Question 32

Mitral valve prolapse causes PVCs, including runs of VT and multifocal PVCs. Is this considered a benign condition?

Answer 32

with MVP, yes, it is benign

Question 33

What is it called if a PVC falls on a T wave?

Answer 33

R on T phenomenon

Question 34

What are the rate ranges for tachyarrhythmias? (there are 3 types)

Answer 34

Question 35

What does paroxysmal mean?

Answer 35

sudden

Question 36

Paroxysmal Atrial Tachycardia and Paroxysmal Ventricular Tachycardia are typically referred to as what?

Answer 36

supraventricular tachycardia (SVT)

Question 37

What are ways to distinguish between SVT and VT?

Answer 37

Question 38

V-fib is considered a type of cardiac arrest, what are two other types?

Answer 38

1. cardiac standstill (asystole)
2. pulseless electrical activity (PEA)

Question 39

Wolff-Parkinson-White Syndrome presents with what EKG change?

Answer 39

the presence of a delta wave between the P wave and the QRS complex

Question 40

What bundle causes WPW syndrome?

Answer 40

the bundle of Kent

Question 41

What occurs in patients with Lown-Ganong-Levine (LGL) Syndrome?

Answer 41

the AV node is bypassed by the “James bundle”, conducting atrial depolarizations directly to the bundle of His immediately