Cardiac Arrhythmias Flashcards
What is an Arrhythmia?
-Abnormality in HR or Rhythm
Where can Arrhythmia’s occur?
1) Supraventricular
-Above AV node
-At AV junction
-Within AV node
2) Ventricular
-Within the ventricles
What are symptoms of Arrhythmia?
-Dizzy/light headed
-Palpitations
-Chest pain
-Fatigue
-Occasionally decrease in consciousness
-BP drop
-Small no of people have cardiac arrest
How do we manage cardiac arrhythmia’s?
-Treat underlying disease
-Drug therapy
-Non-pharmacological
Electrical cardioversion / Pacemakers / Defibrillators
What underlying diseases can cause cardiac arrhythmias?
Hypo/hyperthyroidism
Cardiomyopathy
What is Class 1 of the Vaughan Williams anti-arrhythmic drugs?
Block sodium channels
-Quinidine, Procainamide, Disopyramide, Flecainide, Lignocaine
What is Class II of the Vaughan Williams anti-arrhythmic drugs?
B-adrenoceptor antagonists (atenolol, sotalol)
What is Class III of the Vaughan Williams anti-arrhythmic drugs?
Prolong action potential and prolong refractory period, suppress re-entrant rhythms
-Amiodarone, Sotalol
What is Class IV of the Vaugh Williams anti-arrhythmic drugs?
Calcium channel antagonists, impair impulse propagation in nodal and damaged areas
-Verapamil, Digoxin, Adenosine
What happens to the SA node sinus bradycardia?
SA node fires at a slow rate
What happens in sinus node disease?
SA node fails to generate electrical impulse
-Mainly idiopathic (fibrosis of conduction tissue)
-Some secondary AMI or cardiomyopathies
What happens in AV node disease? ‘Heart Block’
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
What drug is given to increase a patients heart rate?
Atropine
What does a PPM (permanent pacemaker) do?
Delivers small electrical impulses to myocardial tissue if detects an inappropriate rhythm, each person has a individual set threshold
What happens in a ventricular tachycardias?
-Ventricular ectopics
-Tosades de pointes
-Ventricular fibrillation -CARDIAC ARREST!!
What happens in a supracentricular arrythmias in the atria?
-Sinus tachy
-SInus node re-entry tachy
-AF
-Atrial flutter
-Atrial tachy
What happens in a supracentricular arrhythmia, in the AV junction?
-AV junctional tachy
-Wolff-Parkinson White Syndrome
What happens in Sinus Tachycardia? (ST)
-Increase in HR but normal rhythm
-Normal response to exercise
-Infection, decreased BP, Anaemia, Thyrotoxicosis, Hypovolaemia, Shock, PE
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!
Atrial flutter
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!
Wolff-Parkinson White Syndrome
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
Ventricular Tachycardia (VT)
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
Torsades de pointes
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
Ventricular Fibrillation
‘Cardiac Arrest’
–> CPR/DEFIB
–> Irreversible damage if the patient survives!
How does Direct Current Cardioversion work?
Overrides disordered conduction, allows the SA node to regain control of HR, patient is briefly sedated.
