EKG II - Arrhythmias

Question 1

Arrhythmia

Answer 1

Any disturbance to rate, regularity, site of origin (other than SA node), or conduction of electrical impulse

Question 2

Causes of Arrhythmias

Answer 2

HIS DEBS

Hypoxia
Ischemia and Irritability
Sympathetic stimulation
Drugs
Electrolyte disturbance
Bradycardia
Stretch

Question 3

Rhythm Analysis

Answer 3

1. Rate
2. Regularity
3. P waves
4. PR interval
5. QRS duration

Question 4

Calculating Rate

Answer 4

use R waves
300-150-100-75-60-50
300/# of large boxes
1500/# of small boxes

Question 5

PR Interval

Answer 5

Normal: 0.12 - 0.20 sec

Question 6

QRS Duration

Answer 6

Normal: 0.04 - 0.12 sec

Question 7

Arrhythmias of Sinus Origin

Answer 7

Usual conduction pathway, but too fast, slow, or irregular

Question 8

Ectopic Rhythms

Answer 8

Electrical activity originates elsewhere from sinus node

Question 9

Reentrant Arrhythmias

Answer 9

Electrical activity is trapped in an electrical “racetrack”

Question 10

Conduction Blocks

Answer 10

Originates in sinus node and follows usual conduction but encounters unexpected delays

Question 11

Pre-excitation Syndromes

Answer 11

Electrical activity follows accessory pathways

“short circuit”

Question 12

Sinus Tachycardia

Answer 12

> 100 bpm

exercise, CHF, lung disease, hyperthyroidism

Question 13

Sinus Bradycardia

Question 14

Sinus Arrhythmia

Answer 14

Slightly irregular
Normal phenomenon reflecting HR variations with breathing
Inspiration accelerates HR
Expiration decelerates HR

Question 15

Sinus Arrest

Answer 15

Sinus node stops firing

Other myocytes take over pacing (escape beats)

Question 16

Asystole

Answer 16

Electrical inactivity

No cardiac output, no blood flow

Question 17

Junctional Escape Rhythm

Answer 17

Rescues inadequate sinus node by providing one or series of escape beats
Depolarization occurs near AV node (P wave usually missing)

Question 18

Atrial & Junctional Premature Beats

Answer 18

Ectopic supraventricular

premature atrial beat (PACs)

Question 19

Paroxysmal Supraventricular Tachycardia

Answer 19

(sustained supraventricular arrhythmia)
PSVT
Sudden, initiated by PAC or juctional, and abrupt termination
Carotid massage

Question 20

Atrial Flutter

Answer 20

(sustained supraventricular arrhythmia)
Regular, saw-toothed
Atrial rate: 250 - 350 bpm
AV node becomes overwhelmed so not every atrial impulse results in QRS complex

Question 21

Atrial Fibrillation

Answer 21

(sustained supraventricular arrhythmia)
Irregularly, irregular w/out discernible p waves
Atrial rate: 350 - 500 bpm

Question 22

Multifocal Atrial Tachycardia

Answer 22

(sustained supraventricular arrhythmia)
at least 3 different p wave morphologies (p waves of variable shapes)
Irregular rate: 100 - 200 bpm

Question 23

Paroxysmal Atrial Tachycardia

Answer 23

(sustained supraventricular arrhythmia)
PAT
Regular rate: 100 - 200 bpm
enhanced automaticity of ectopic atrial foci or reentrant loop w/in atria

Carotid massage has no effect (differentiate from PSTV)

Question 24

Premature Ventricular Contractions

Answer 24

PVCs
wide QRS from conduction not following normal pathway of depolarization
Bigeminy 1 PVC : 1 normal beat
Trigeminy 1 : 2

Concerning: frequent, runs of 3 or more, multiform
predispose pt to VT or VF

Question 25

Ventricular Tachycardia

Answer 25

Run of 3 or more PVCs

Rate 120 - 200 bpm

Question 26

Torsades De Pointes

Answer 26

“twisting of points”
polymorphic form of VT
VT occurring in pts with prolonged QT intervals

Question 27

Ventricular Fibrillation

Answer 27

Pre-terminal event (dying heart)
no true QRS complexes
No cardiac output

Question 28

Accelerated Idioventricular Rhythm

Answer 28

Benign rhythm seen during acute MI
Rate: 50 - 100 bpm
Ventricular escape focus that has accelerated sufficiently to drive heart