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Flashcards in Arrhythmias and Therapy Deck (36)
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1

What is FIRST-DEGREE AV Block?

Disease of Electrical Conduction System:

Delay in the Impulse being Conducted through the AV Node

*PR Interval Prolongation (>0.2secs)

2

What is SECOND-DEGREE AV Block: MOBITZ I/WENCKEBACH?

Almost Always a Disease of AV Node

ECG Features:

1) Progressive Prolongation of PR Interval (>0.2secs) on Consecutive Beats
2) Followed by a Non-Conducted P Wave or 'Dropped' QRS Complex

3

What is SECOND-DEGREE AV Block: MOBITZ II?

Almost Always a Disease of the His-Purkinje System

ECG Features:

1) Intermittent Non-Conducted P Waves/Dropped QRS Complexes
2) PR Interval Remains Constant

4

What is THIRD-DEGREE or COMPLETE Heart Block?

Complete Absence of AV Conduction

ECG Features:

1) Atrial and Ventricular Conduction Rates are Independent From One Another
2) P Waves Bear No Relation to QRS Complexes

5

Describe ATRIAL FIBRILLATION (AF):

Type of Supraventricular Tachycardia

Disorganised Atrial Activity and Contraction

ECG Features:

1) Irregularly Irregular Rhythm
2) Atrial Rate >350bpm
3) No P Waves - Fibrillatory Waves Mimic P Waves
4) Variable Ventricular Rate

6

Describe ATRIAL FLUTTER:

Type of Supraventricular Tachycardia

Caused by Re-Entry Circuit within the Right Atrium

ECG Features:

1) Narrow QRS Complex Tachycardia
2) Atrial Rate = 250-350bpm
3) "Saw-Tooth" Pattern of Flutter Waves
4) Regular Ventricular Rate

7

How would a patient with AF PRESENT?

May be Asymptomatic

Possible Symptoms:

1) Palpitations
2) Dyspnoea
3) Chest Pain
4) Fatigue

8

What INVESTIGATIONS would be used to diagnose AF?

1) ECG
2) FBC - specifically Thyroid Function
3) Echocardiography

9

What is the purpose of CLASS I ANTI-ARRHYTHMIC (AA) drugs?

*Na+ Channel Blockers, i.e. Disopyramide

1) Manipulate Phase 0 of Non-Pacemaker Action Potentials (AP)
2) Can Delay the Onset of Depolarisation and Repolarisation of the Ventricles
3) Can Prolong Effective Refractory Period (ERP) between Heart Beats (Class Ia)

10

What is the purpose of CLASS II AA drugs?

*Beta-Blockers, i.e. Atenolol and Bisoprolol

* < HR

1) < Sympathetic Stimulation
2) Block Beta-1 Receptors at the SA and AV Nodes
3) Delay Phase 4 Depolarisation of Pacemaker APs
4) < SA Node Firing
5) Slow AV Node Conduction

11

What is the purpose of CLASS III AA drugs?

* K+ Channel Blockers, i.e. Amiodarone

1) Manipulate Phase 3 of Non-Pacemaker APs
2) Prolong Repolarisation of the Ventricles
3) Prolong ERPs between Heart Beats

12

What is the purpose of CLASS IV AA drugs?

*Calcium Channel Blockers, i.e. Verapamil and Diltiazem (Rate-Limiting)

* < HR

1) Depress Phase 4 Depolarisation of Pacemaker APs

13

What is the purpose of DIGOXIN?

*Cardiac Glycoside

1) Inhibits Na+/K+ ATPase Pump
2) +ve Inotrope - Improves Strength of Contraction
3) Allows More Ca2+ to be Available

14

What COHORT is Digoxin commonly prescribed to?

Elderly for Rate Control

15

What are the ISSUES surrounding Digoxin use?

Used by Elderly, often with Renal Impairment

Causes Toxicity due to Prolonged Half-Life

Has many Side-Effects, i.e. Nausea; Bradycardia; Arrhythmias

16

What is the TREATMENT for Digoxin TOXICITY?

Digiband

17

What are the ISSUES surrounding AMIODARONE use?

Interacts with Other Drugs, i.e. Digoxin

Many Side Effects Causing Tissue Abnormalities, i.e. Thyroid; Pulmonary Fibrosis

18

Why is it IMPORTANT to ANTICOAGULATE patients with AF?

> Risk of Clotting in RA due to Impaired RA Contractility

> Risk of Stroke and/or Peripheral Emboli

19

Other than AF, under what CIRCUMSTANCES would ANTICOAGULATION be INDICATED?

DVT/PE

After Surgery

Prolonged Immobilisation

20

Name a SIGNIFICANT ORAL ANTICOAGULANT:

Warfarin

21

What are Warfarin's MECHANISMS of ACTION?

Inhibits Clotting Factors II, VII, IX and X

Vit K Antagonist

22

What are the ISSUES surrounding Warfarin use?

Drug Interactions

Can > Warfarin Activity - Promote Bleeding

Can < Warfarin Activity - Promoting Clotting

23

How can Warfarin effects be MONITORED?

1) Regular International Normalised Ratio (INR)
2) CHADS2 Score

24

How can Warfarin SIDE EFFECTS be ATTENUATED?

1) Be Aware of Alterations in Therapy
2) Patient Education
3) < Alcohol Intake

25

What might be a SAFER ALTERNATIVE to Warfarin in ANTICOAGULATIVE THERAPY?

Dabigatran or Rivaroxaban

26

Describe WOLFF-PARKINSON-WHITE (WPW) Syndrome:

Accessory Pathway (Bundle of Kent) Used Instead of AV Node to Conduct Impulses Between Atria and Ventricles

Can Facilitate Atrial and Ventricular Arrhythmias

Also, a Type of Re-Entrant Tachycardia via Accessory Pathway

27

Explain SUPRAVENTRICULAR TACHYCARDIAS (SVTs):

Abnormally Fast Heart Rhythm

Arising from Improper Electrical Activity Above the Ventricles

Ex) AF; Atrial Flutter; WPW

28

Describe VENTRICULAR TACHYCARDIA (V Tach):

Abnormally Fast and Regular Heart Rhythm

Arising from Improper Electrical Activity Provided to the Ventricles

29

What are the SYMPTOMS of V Tach?

1) Palpitations
2) Chest Pain
3) Dyspnoea
4) Dizziness
5) Syncope

30

What INVESTIGATIONS would be used to diagnose V Tach?

1) ECG
2) FBC
3) Angiography