Dysrhythmias

Question 1

What are dysrhythmias?

Answer 1

Disruptions in the normal rhythm of the heart, affecting cardiac output efficiency.

Question 2

Why are severe dysrhythmias significant in neonates?

Answer 2

They can compromise perfusion and oxygen delivery, leading to systemic consequences.

Question 3

What is required for the management of dysrhythmias?

Answer 3

Understanding cardiac electrophysiology and pharmacologic classes that modulate cardiac conduction.

Question 4

Define tachydysrhythmias.

Answer 4

Heart rate > normal range; typically more responsive to drug therapy.

Question 5

Give an example of tachydysrhythmia.

Answer 5

Supraventricular tachycardia (SVT).

Question 6

Define brady dysrhythmias.

Answer 6

Heart rate < normal range; often require pacing or more advanced intervention.

Question 7

Give an example of brady dysrhythmia.

Answer 7

Congenital AV block.

Question 8

What are premature complexes?

Answer 8

Early depolarizations from atria or ventricles; may be benign or precursor to sustained arrhythmias.

Question 9

What is the function of the SA Node?

Answer 9

Primary pacemaker located in the right atrium; initiates spontaneous depolarization.

Question 10

What is the role of the AV Node?

Answer 10

Relays impulses from atria to ventricles with a physiologic delay allowing ventricular filling.

Question 11

What does the His-Purkinje System do?

Answer 11

Rapidly conducts impulses to the ventricles for coordinated contraction.

Question 12

What generates cardiac action potentials?

Answer 12

Ion exchange during depolarization (Na+ or Ca++ influx) and repolarization (K+ efflux).

Question 13

What are fast potentials?

Answer 13

Found in Purkinje fibers and ventricular myocardium; driven by Na+.

Question 14

What are slow potentials?

Answer 14

Found in SA/AV nodes; driven by Ca++ influx; no true resting potential.

Question 15

What does the P wave represent on an EKG?

Answer 15

Atrial depolarization.

Question 16

What does the QRS complex represent on an EKG?

Answer 16

Ventricular depolarization.

Question 17

What does the T wave represent on an EKG?

Answer 17

Ventricular repolarization.

Question 18

What is the PR interval on an EKG?

Answer 18

AV nodal conduction time.

Question 19

What does the ST segment indicate on an EKG?

Answer 19

Time from ventricular depolarization to repolarization.

Question 20

What disturbances can lead to dysrhythmias?

Answer 20

Automaticity and conduction disturbances.

Question 21

What are Class I drugs in dysrhythmia treatment?

Answer 21

Sodium Channel Blockers.

Question 22

What is the effect of Class IA drugs?

Answer 22

Prolong action potential; used for SVT.

Question 23

Name an example of a Class IA drug.

Answer 23

Quinidine or Procainamide.

Question 24

What is the effect of Class IB drugs?

Answer 24

Shorten action potential; used for ventricular arrhythmias.

Question 25

Name an example of a Class IB drug.

Answer 25

Lidocaine or Mexiletine.

Question 26

What is the effect of Class IC drugs?

Answer 26

Marked slowing of conduction; limited pediatric use.

Question 27

Name an example of a Class IC drug.

Answer 27

Flecainide or Propafenone.

Question 28

What is the function of Class II drugs?

Answer 28

Beta Blockers that decrease sympathetic stimulation.

Question 29

Give examples of Class II drugs.

Answer 29

Propranolol, Esmolol, Metoprolol.

Question 30

What is the effect of Class III drugs?

Answer 30

Potassium Channel Blockers that delay repolarization by inhibiting K+ efflux.

Question 31

Name an example of a Class III drug.

Answer 31

Amiodarone.

Question 32

What caution is associated with Amiodarone?

Answer 32

Pulmonary/hepatic toxicity.

Question 33

What is the function of Class IV drugs?

Answer 33

Calcium Channel Blockers that inhibit slow Ca++ channels.

Question 34

Give examples of Class IV drugs.

Answer 34

Verapamil, Diltiazem.

Question 35

Why is Verapamil contraindicated in neonates?

Answer 35

Due to hypotension risk.

Question 36

What is the role of Class V drugs?

Answer 36

Miscellaneous agents like Adenosine and Digoxin.

Question 37

What does Adenosine do?

Answer 37

Activates K+ currents, causing transient AV block; first-line for SVT.

Question 38

What is the primary action of Digoxin?

Answer 38

Enhances vagal tone, suppresses AV node conduction, increases inotropy.

Question 39

What type of drug is Propranolol and what does it treat?

Answer 39

Non-selective beta-blocker used in thyrotoxicosis, TOF, and SVT.

Question 40

What is the unique characteristic of Esmolol?

Answer 40

Short-acting IV beta-blocker useful intraoperatively or for acute HR control.

Question 41

What are the adverse effects of Amiodarone?

Answer 41

Thyroid, liver, and ocular toxicity.

Question 42

What should be monitored when using Digoxin?

Answer 42

Bradycardia, nausea, arrhythmias; narrow therapeutic window (0.5–2.0 ng/mL).

Question 43

What is the treatment strategy for SVT?

Answer 43

Vagal maneuvers → Adenosine → Propranolol or Digoxin for maintenance.

Question 44

How is Atrial Flutter/Fibrillation managed?

Answer 44

Rate control with beta/calcium blockers, synchronized cardioversion if unstable.

Question 45

What is the treatment for Ventricular Arrhythmias?

Answer 45

Lidocaine or Amiodarone; correct electrolytes.