EKG

Question 1

The basics- what do we check every time?

Answer 1

Rate

Rhythm

Axis

Hypertrophy

Infarction

Wave interval and segment abnormalities

Question 2

Waves and Segments

Answer 2

Waves - Summation Vectors
P, Q, R, S, T, U

Segments
ST

Question 3

Intervals

Answer 3

PR less than 0.2 seconds (one big – five little boxes)

QRS less than 0.12 seconds (three little boxes)

QT 0.44 seconds Bazett’s formula

Question 4

Rate

Answer 4

300, 150, 100, 75, 60, 50

Six second strip - Multiply by 10

(where the leads break is 3 seconds)

Question 5

Leads

Answer 5

Lead I- across chest,

Lead 2- down across the heart, “physiologic lead”

Lead 3-

AVF - straight down

Question 6

V leads- what plane?

Answer 6

horizontal

Question 7

QRS Sequence of Ventricular Depolarization

Answer 7

Depolarization starts at the ventricular septum (Q wave) and the endocardial surfaces.

Average current flows from the base of the heart to the apex (R wave).

At the end of depolarization, the current reverses, flows toward the outer walls of the ventricles near the base (S wave).

Question 8

Atrial rhythm

Answer 8

Up right P waves, narrow QRS

Question 9

Junctional rhythm

Answer 9

Absent or inverted P waves, narrow QRS

Question 10

Ventricular rhythm

Answer 10

No p waves

Wide QRS complexes

Question 11

Repetitive sequence rhythms

Answer 11

Bigeminal, Trigeminal, Quadrigeminal

A series-pattern of ectopic depolarizations, either atrial or ventricular in origin

Question 12

Automaticity issues

Answer 12

Escape beats with refractory periods

premature beats- irritable focus, reentry

Question 13

Supraventricular rhythms with narrow QRS complexes

Answer 13

Sinus/ Atrial

Junctional

Wolf-Parkinson-White (WPW)

Question 14

Sinus/Atrial

rhythm

Answer 14

Sinus arrhythmia
Wandering pacemaker, multifocal atrial tachycardia (MAT)
Paroxysmal atrial tachycardia (PAT)

Artial flutter- Singular atrial focus – reentry mechanism

Artial fib- Lack of any organized atrial activity

Question 15

Junctional rhythms

Answer 15

Paroxysmal junctional tachycardia (PJT)

AV nodal reentry

Question 16

Wolf-Parkinson-White (WPW)

Answer 16

Accessory conduction pathway (bundle of Kent)
Delta waves
Often has the appearance of an IWMI, this determination must be interpreted carefully
Shortened PR interval

Question 17

Wandering pacemaker

Answer 17

irregular rhythm
P’ wave shape varies
atrial rate less than 100
irregular ventricular rhytm

Question 18

What does atrial flutter look like?

Answer 18

sawtooth

2 or 3 P waves per QRS

Question 19

what makes a junctional rhythm?

Answer 19

no p waves.

also, slower, because intrinsic rate of junction is slower

Question 20

wolf parkinson white

Answer 20

p wave smashing into the QRS

Question 21

First degree AV block

Answer 21

Prolonged PR interval - > 0.2 seconds

Question 22

Second degree AV block

Answer 22

Variable penetration of AV conductions – lone P waves without a QRS conduction following

2 types: Wenckebach and Mobitz

Question 23

Type I Second degree AV block

Answer 23

(conduction abnormality in the AV node and heavy parasympathetic influence)
Wenckebach
Progressively prolonged PR intervals with a subsequent dropped beat and lone P wave – usually a fixed ratio/pattern
Vagal maneuvers

Question 24

Type 2 Second degree AV block

Answer 24

Mobitz
Failure of AV conduction in a fixed ratio/pattern, the PR interval is not gradually increasing in length
Widened QRS

Question 25

Third degree AV block

Answer 25

Complete Atrial and Ventricular dissociation – both are being independently paced

Question 26

Ventricular Dysrhythmias

Answer 26

Wide QRS complex tachycardia - Supraventricular vs. ventricular Ventricular Tachycardia - Irritable focus of a ventricular origin – usually reentry mechanism Torsades de Pointes - twisted ribbon Ventricular fibrillation Multiple irritable automatic foci depolarizing

Question 27

number one cause of prolonged QT syndrome

Answer 27

hypomagnesemia can also be caused by medications, etc.

Question 28

Ventricular Blocks: Bundle branch blocks

Answer 28

Lack of synchronization of the bundle branches Right Bundle Branch Block - Left bundle conducts first - Best viewed inV1 V2 Left - Right bundle conducts first - Best viewed in V5 V6

Question 29

QRS sequence of depolarization

Answer 29

Depolarization starts at the ventricular septum (Q wave) and the endocardial surfaces. Average current flows from the base of the heart to the apex (R wave). At the end of depolarization the current reverses, flows toward the outer walls of the ventricles near the base (S wave).

Question 30

Axis

Answer 30

Vector direction and mass summation - Limb leads – frontal plane (Determine axis) - Chest Leads – horizontal plane (Determine rotation) - 0-90 degrees is normal (actually -30 to 110) - Isoelectric point - ---Right angle from the axis plane