Arrhythmias Flashcards
Positive inotropic effect
Depolarisation effect
Makes your heart muscle contractions stronger
Increased cardiac output to a normal level
Increases the amount of blood our heart can pump out
Examples: dopamine, digoxin, adrenaline
Negative inotropic effect
Hyperpolarisation effect
Weaken the heart’s contractions
Slow heart rate
Treat high blood pressure, heart failure, angina
Examples: beta blockers, flecainide, RL-CCB, digoxin
Treatment for ectopic beats
Beta blockers - rarely used as these are spontaneous and resolve without treatment
Types of atrial fibrillation
Paroxysmal - occurs intermittently and stops on its own within 7 days
Non-paroxysmal - persistent and lasts longer than 7 days
Long-standing persistent - lasts longer than a year
Treatment of acute AF with life-threatening haemodynamic instability
Emergency electrical cardioversion without delay to achieve anticoagulation
Treatment of acute AF without life-threatening haemodynamic instability if onset <48 hours
Rate or rhythm control
Treatment of acute AF without life-threatening haemodynamic instability if onset >48 hours
Rate control only
Examples of drugs for cardioversion (rhythm control) in acute AF without life-threatening haemodynamic instability if onset <48 hours
Flecainide, amiodarone
Maintenance treatment of non-paroxysmal AF
1st: Monotherapy rate control with beta blocker, RL-CCB or digoxin
2nd: Dual therapy with two of the first line drugs
3rd: Rhythm control with sotalol, propafenone, amiodarone, flecainide or dronedarone
Treatment if onset non-paroxysmal AF is >48 hours and what is required before initiating this treatment
Electrical cardioversion
Patient must be fully anticoagulated for at least 3 weeks before and 4 weeks after
Treatment of paroxysmal AF with symptomatic episodes
Pill in pocket approach with flecainide
I seen in practice atenolol being used for this
When would digoxin be used as first line for non-paroxysmal AF?
In predominately sedentary patients where beta blocker or RL-CCB doesn’t control symptoms
Drug treatment that may be required post electrical cardioversion
Standard beta blocker
Sotalol, propafenone, amiodarone, or flecainide
When should amiodarone be started and for how long should it be continued after electrical cardioversion?
4 week before and continued for up to 12 months after
Treatment of paroxysmal AF
1st: Standard beta blocker
2nd: Sotalol, Propafenone, Amiodarone or Flecainide
How to assess risk of stroke? What is the score that required anticoagulation therapy?
CHADsVASc
Men = >1
Women = >2
Treatment of atrial flutter
Reacts less effectively to drug treatment so treat with direct current cardioversion or catheter ablation
Temporary rate control with beta blocker or RL-CCB until sinus rhythm restored
When would direct current cardioversion be used to restore sinus rhythm in atrial flutter?
When haemodynamic instability is present
When would catheter ablation be used to restore sinus rhythm in atrial flutter? What must you ensure before treatment?
Recurrent atrial flutter
Patient has been anticoagulated for 3 weeks if flutter lasts longer than 48 hours
Treatment of paroxysmal supraventricular tachycardia
1st: Usually terminates spontaneously by itself
2nd: Reflex vagal stimulation e.g., immerse face in ice-cold water or carotid sinus massage with ECG monitoring
3rd: IV adenosine
4th: IV verapamil but should be avoided if recently treated with beta-blocker
Treatment of recurrent symptoms of paroxysmal supraventricular tachycardia
Catheter ablation
Prevention of further episodes of paroxysmal supraventricular tachycardi
Beta blockers, Flecainide, Propafenone, or RL-CCB
Treatment of arrhythmias post-MI
Tachycardia
Best not to administer anti-arrhythmic until ECG record
Bradycardia
1st: IV atropine
2nd: IVI adrenaline
Treatment of Pulseless Ventricular Tachycardia or Ventricular Fibrillation
Resuscitation
Treatment of unstable sustained ventricular tachycardia
Direct current cardioversion followed by IV amiodarone
Repeat current cardioversion if necessary
Treatment of stable ventricular tachycardia
Amiodarone
Flecainide, propafenone, lidocaine (less so)
Treatment of stable ventricular tachycardia if sinus rhythm not restored
Direct current cardioversion or catheter ablation
Treatment of non-sustained ventricular tachycardia
Beta blocker
Maintenance treatment for patients with ventricular tachycardia
Only used if high risk of cardiac arrest
Implantable cardioverter defibrillator
Can add beta blocker / amiodarone
Treatment of Torsade’s de Pointes
Usually self-limiting
IV magnesium sulphate
Beta blocker and atrial / ventricular pacing
NOT AN ANTI-ARRHYTHMIC (can cause QT prolongation)
Drugs that can cause Torsade’s de Pointes
Amiodarone
Sotalol
Macrolides
Haloperidol
SSRIs
TCAs
Antifungals
Lithium
Treatment of Supraventricular Arrhythmias
IV Adenosine
IV Verapamil followed by oral treatment is preferred if asthmatic
Oral digoxin (IV not effective for rapid control of ventricular rate)
IV beta blocker can achieve rapid control
When would verapamil be contraindicated?
AF or atrial flutter WITH Wolff-Parkinson White Syndrome
Drugs used for both Supraventricular and Ventricular Arrhythmias
Amiodarone
Beta blockers
Disopyramide
Flecainide
Procainamide
Propafenone
How many anti-arrhythmic drug classifications are there?
4
How are the anti-arrhythmic drugs classified?
According to the primary mechanism of action
Class I anti-arrhythmic
Membrane stabilising drugs - block sodium channels (sodium influx inhibited)
Rapid inhibition: Lidocaine
Slow inhibition: Flecainide, propafenone
Class II anti-arrhythmic
Beta blockers
Class III anti-arrhythmic
Prolong the cardiac action potential by inhibiting potassium efflux
Amiodarone, sotalol
Class IV anti-arrhythmic
Inhibit calcium influx
RL-CCB
Why isn’t sotalol used as rate control?
Can prolong the QT interval which can occasionally lead to life threatening ventricular arrhythmias
Sotalol monitoring requirements
ECG and measurement of corrected QT interval
Serum electrolytes (K+ , Mg2+, Ca2+)
(electrolyte disturbance i.e. hypokalaemia, hypomagnesaemia, and hypercalcaemia, should be corrected before starting sotalol and during its use)
