Arrhythmias

Question 1

True or False: People have more arrhythmias during surgery

Answer 1

FALSE: people have less due to cardiac depressant anesthetics

Question 2

SA Node

Answer 2

Controls firing rate for the heart.

Calcium leak channels depolarize and generate AP

Question 3

AV Node

Answer 3

Also controlled by Ca leak channels

Question 4

Ventricles

Answer 4

Controlled by sodium channels

Question 5

Role of Potassium in electrical cycle

Answer 5

K leaves the cell causing depolarization and making inside of cell more negative

Question 6

Class I Antiarrhythmics

Answer 6

Block Na channels/depression of phase 0 depolarization

Most effective against ventricular arr. because ventricles depolarize with Na channels

Question 7

Class IA Antiarrhythmics

Answer 7

Moderate depression of Na channels and prolongs repolarization

I.e. Quinide, procainamide, dispyramide

Question 8

Class IB Antiarrhythmics

Answer 8

Weak depression of Na channels and shortens repolarization

I.e. lidocaine, mexiletine, phenytoin, tocainide

Question 9

Class IC Antiarrhythmics

Answer 9

Strong depression of Na channels with little effect on repolarization

I.e. flecainide, propafenone, moricizine

Question 10

Class II Antiarrhythmics

Answer 10

Beta adrenergic blocking effects.
Block SNS stimulation to heart
Atrial and ventricular effects

I.e. -olol medications

Question 11

Class III Antiarrhythmics

Answer 11

Prolongs repolarization by blocking potassium channels. Prolong action potential duration and refractoriness

I.e. amiodarone

Question 12

Class IV Antiarrhythmics

Answer 12

Calcium Channel blockers
used for SA/AV node and atrial arrhythmias

I.e. verapamil, diltizem

Question 13

Main causes of intraoperative arrhythmias

Answer 13

*structural heart disease
General factors
Transient imbalance

Question 14

First line management of A fib

Answer 14

Ventricular rate control

Lenient is better <110 bpm

Question 15

Major risk with Afib and why

Answer 15

Thromboembolic stroke.

Atria are quivering which allows pooling of blood. When return regular rhythm, push the clots in pool of blood out and can go to brain

Question 16

Medications for Afib rate control

Answer 16

BB preferred for those with CAD or systolic dysfunction

CCB can prolong AV nodal refractoriness slowing ventricular rate (verapamil/diltiazem)

Amiodarone: restore and maintain sinus rhythm

Digoxin

Question 17

Med that works on purine receptors

Answer 17

Adenosine

Question 18

What do purine receptors do

Answer 18

Slow SA and AV conduction (adenosine)

Question 19

Adenosine produces…

Answer 19

Slowing SA and AV nodal conduction (hyperpolarizes by opening K channels and inhibiting Ca channels)

Bronchoconstriction

Dilation of cerebral and coronary vessels

Modulation of catecholamine release

Stops the heart so regular HR can start up again when heart resumes beating

Question 20

Adenosine MOA

Answer 20

Opens K channels and inhibits Ca channels

Hyperpolarizes nodal cells making it harder to reach action potential

Slows conduction in SA/AV node

Question 21

Medication for PVCs

Answer 21

Usually not needed but if symptomatic, can give BB

Question 22

Medication for Vtach

Answer 22

Amiodarone

Question 23

Medication for Vfib

Answer 23

Amiodarone to prevent recurrence

Question 24

Medication for torsades de pointes

Answer 24

Mag sulfate