L11: ECG Arrhythmias (Shih)

Question 1

CONS of monitoring ECG during anesthesia

Answer 1

• HR may be off by 10%
• no info on mechanical activity of heart
• additional set up time
• stable ECG signal can be challenging to get
• patient injury can occur from attachment sites

Question 2

2 classes of antiarrhthmics

Answer 2

Ventricular

Supraventricular

Question 3

P wave correlates to:

Answer 3

Sinus node and atrial tissue depolarization and atrial contraction

Question 4

PR interval

Answer 4

AV node

Question 5

QRS complex

Answer 5

Ventricular depolarization/contraction

Question 6

If impulse comes from ventricle, QRS looks:

Answer 6

Wide and bizarre

Question 7

If impulse comes from supraventricular, QRS looks:

Answer 7

Normal
P waves present
Faster HR

Question 8

If impulse comes from junctional, QRS looks:

Answer 8

Normal
No p waves
Slower HR

Question 9

Normal HR from supraventricular/junctional/ventricular

Answer 9

Supra: 100-120
Junctional: 80-90
Ventricular: 40-60***

sinus rate faster than ventricular rate

Question 10

A fib characterized by what rhythm?***

Answer 10

Irregularly irregular

-atrial rate ~200 bpm, and ventricle just trying to keep up

Question 11

When to tx A fib

Answer 11

• patient sluggish
• ventricular rate very fast
• tx: class 2 beta-blockers (esmolol) and class 4 Ca channel blockers (Ditiazem)
• do NOT tx if HR slow

Question 12

Tx for 2nd degree AV block

Answer 12

• don’t tx if p otherwise ok
• remove primary cause
• tx: atropine, glycopyrrolate

Question 13

Type I 2nd degree AV block

Answer 13

PR interval gradually increases before AV block occurs

Question 14

Type II 2nd degree AV block

Answer 14

PR interval the same before AV block occurs (clinically the same as type I)

Question 15

Junctional rhythm and tx

Answer 15

AV node taking over beat

Tx: atropine (facilitates comm. b/w SA node and AV node)

*if dz has mechanical origin, drugs won’t work and may need a pacemaker

Question 16

Tx of idioventricular rhythm or escape rhythm***

Answer 16

NO LIDOCAINE

Tx: atropine, glycopyrrolate, +/- pacemaker to speed up rate

Question 17

Bigeminy***

Answer 17

Alternates b/w VPC and normal complex

Thiopental can cause BIGEMINY***

Question 18

Causes of V tach

Answer 18

Ischemia
Clot
Heart attack
HBC/bruising
Electrolyte disturbance (ie. Blocked cat)

Question 19

Tx of V tach

Answer 19

Lidocaine 2mg/kg

2nd choice: procainamide
3rd choice: esmolol or ditiazem

Question 20

When should you tx VPCs?***

Answer 20

• Multifocal
• VPC getting close to previous T wave (can lead to V fib)
• cardiovascularly unstable

Tx = defibrilator***

Question 21

Pros of monitoring ECG during anesthesia

Answer 21

• HR
• Info on electrical activity of heart
• can correlate electrical and mechanical components of cardiac function
• arrhythmias are first sign of CV dysfx