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.
What does Cardioversion increase the risk of and how do we manage this?
Thromboembolism
-Need anticoagulation for 3 weeks before and 4 weeks after treatment
-Patient often doesn’t always stay in normal sinus rhythm
What does radiofrequency ablation/cryoablation do?
*need to know exactly what point is responsible for the arrhythmia
-RF energy / freezing destroys tissue and disrupts conduction pathway
-90% success rate
What are used in combination when someone has a cardiac arrest?
Defib + CPR
What is an internal cardioversion defibrillator (ICDs) used for?
-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
