Cardiac Arrhythmias

Question 1

What is an Arrhythmia?

Answer 1

-Abnormality in HR or Rhythm

Question 2

Where can Arrhythmia’s occur?

Answer 2

1) Supraventricular
-Above AV node
-At AV junction
-Within AV node
2) Ventricular
-Within the ventricles

Question 3

What are symptoms of Arrhythmia?

Answer 3

-Dizzy/light headed
-Palpitations
-Chest pain
-Fatigue
-Occasionally decrease in consciousness
-BP drop
-Small no of people have cardiac arrest

Question 4

How do we manage cardiac arrhythmia’s?

Answer 4

-Treat underlying disease
-Drug therapy
-Non-pharmacological
Electrical cardioversion / Pacemakers / Defibrillators

Question 5

What underlying diseases can cause cardiac arrhythmias?

Answer 5

Hypo/hyperthyroidism
Cardiomyopathy

Question 6

What is Class 1 of the Vaughan Williams anti-arrhythmic drugs?

Answer 6

Block sodium channels
-Quinidine, Procainamide, Disopyramide, Flecainide, Lignocaine

Question 7

What is Class II of the Vaughan Williams anti-arrhythmic drugs?

Answer 7

B-adrenoceptor antagonists (atenolol, sotalol)

Question 8

What is Class III of the Vaughan Williams anti-arrhythmic drugs?

Answer 8

Prolong action potential and prolong refractory period, suppress re-entrant rhythms
-Amiodarone, Sotalol

Question 9

What is Class IV of the Vaugh Williams anti-arrhythmic drugs?

Answer 9

Calcium channel antagonists, impair impulse propagation in nodal and damaged areas
-Verapamil, Digoxin, Adenosine

Question 10

What happens to the SA node sinus bradycardia?

Answer 10

SA node fires at a slow rate

Question 11

What happens in sinus node disease?

Answer 11

SA node fails to generate electrical impulse
-Mainly idiopathic (fibrosis of conduction tissue)
-Some secondary AMI or cardiomyopathies

Question 12

What happens in AV node disease? ‘Heart Block’

Answer 12

Failure of AV node to conduct electrical impulse to ventricles
-Frequently idiopathic
-Also secondary AMI, congenital defects, infection, surgery (valves) and drugs
-B-blockers, Digoxin, Verapamil

Question 13

What drug is given to increase a patients heart rate?

Answer 13

Atropine

Question 14

What does a PPM (permanent pacemaker) do?

Answer 14

Delivers small electrical impulses to myocardial tissue if detects an inappropriate rhythm, each person has a individual set threshold

Question 15

What happens in a ventricular tachycardias?

Answer 15

-Ventricular ectopics
-Tosades de pointes
-Ventricular fibrillation -CARDIAC ARREST!!

Question 16

What happens in a supracentricular arrythmias in the atria?

Answer 16

-Sinus tachy
-SInus node re-entry tachy
-AF
-Atrial flutter
-Atrial tachy

Question 17

What happens in a supracentricular arrhythmia, in the AV junction?

Answer 17

-AV junctional tachy
-Wolff-Parkinson White Syndrome

Question 18

What happens in Sinus Tachycardia? (ST)

Answer 18

-Increase in HR but normal rhythm
-Normal response to exercise
-Infection, decreased BP, Anaemia, Thyrotoxicosis, Hypovolaemia, Shock, PE

Question 19

What type of Arrhythmia is this?
-Re-entry circuit within the R atrium
-Rapid Atrial rhythm (about 300bpm)
-ECG shows a saw tooth pattern
-Ventricles usually beat once for every 2-4 atrial flutter waves
-Stasis of blood in atrial - need anticoagulation!

Answer 19

Atrial flutter

Question 20

What syndrome causes, accessory pathway conduction electrical pulse direct from atria to ventricles, and by-pass AV node,
-Ventricular rate up to 600bpm
-Is SERIOUS and life threatening
-AV node slows down electrical activity, therefore AV node can be bypassed!

Answer 20

Wolff-Parkinson White Syndrome

Question 21

What type of Arrhythmia, causes:
-Occasional palpitations from extra ventricular beats (ectopics)
-Frequent/runs of ectopic beats
-Five or more ventricular beats occur consecutively
-Caused by AMI, IHD, Cardiomyopathies, Myocarditis, Valvular disease

Answer 21

Ventricular Tachycardia (VT)

Question 22

What type of Arrhythmia is this?
-Due to QT prolongation
-Caused by congenital / hypokalaemia / hypomagnesaemia
-Caused by, drugs - tricyclic antidepressants / haloperidol / lithium / phenothiazines / erythromycin and clarithromycin / certain antiarrhythmics

Answer 22

Torsades de pointes

Question 23

What type of arrhythmia is this?
-Rapid and uncoordinated contraction of the ventricular tissue
-Severely compromises cardiac output
-Lose consciousness within 10-20 seconds
-Most common cause of death due to AMI

Answer 23

Ventricular Fibrillation
‘Cardiac Arrest’
–> CPR/DEFIB
–> Irreversible damage if the patient survives!

Question 24

How does Direct Current Cardioversion work?

Answer 24

Overrides disordered conduction, allows the SA node to regain control of HR, patient is briefly sedated.

Question 25

What does Cardioversion increase the risk of and how do we manage this?

Answer 25

Thromboembolism
-Need anticoagulation for 3 weeks before and 4 weeks after treatment
-Patient often doesn’t always stay in normal sinus rhythm

Question 26

What does radiofrequency ablation/cryoablation do?

Answer 26

*need to know exactly what point is responsible for the arrhythmia
-RF energy / freezing destroys tissue and disrupts conduction pathway
-90% success rate

Question 27

What are used in combination when someone has a cardiac arrest?

Answer 27

Defib + CPR

Question 28

What is an internal cardioversion defibrillator (ICDs) used for?

Answer 28

-Given to high risk pts with resistant VT’s
-Monitors rate and rhythm
-Delivers rapid rate impulses - to regain control and then slows down
-If it fails it delivers internal electric shocks