Arrhythmia Treatment Flashcards
What are the different types of arrhythmia?
Sinus arrhythmia.
Bradycardias - heart block.
Tachycardias - supraventricular arrhythmia (tachycardia; AF); ventricular arrhythmia (tachycardia; VF).
What are class I antiarrhythmics?
Acts on Na+ channels in non-nodal cells that are responsible for depolarisation.
More effective at higher HR.
Type C - flecainide (strong channel blockers).
What are class II antiarrhythmics?
Prolongs SA discharge and AVN conduction.
Reduces excitability in non-nodal cardiac tissue.
Shortens contractions.
First line for AF (Bisoprolol); suppresses VEs and some VTs.
BBs - atenolol, bisoprolol.
What are class III antiarrhythmics?
Increases AP duration.
Prolongs repolarisation and ERP.
Used for difficult dysrhythmias; life-threatening VT or VF; sustained VT; and AF or atrial flutter.
What is amiodarone?
A class III antiarrhythmic.
Used for VT, occasionally for SVT.
ADRs - hypo/hyperthyroidism, pulmonary fibrosis, grey pigmentation, corneal deposits, LFT abnormalities.
What are class IV antiarrhythmics?
Slows HR (decreases automaticity and AV conduction).
Shortens contractility; use dependent.
Used for paroxysmal SVT, and rate control for AF and flutter.
CCBs - diltiazem, verapamil.
What is digoxin?
Slows conduction.
Reduces the refractory period in myocardium.
Used for AF, atrial flutter, SVT, and heart failure.
Controls ventricular rate, especially if an acute setting with HF/hypotension, and BB/CCB are inefficient.
What is the toxicity of digoxin?
Half-life - 36-48hrs.
Commonly used in the elderly (who have reduced GFR, and increased renal impairment).
Monitor [K+] and [Digoxin] (serious if [K+] = low).
What are the ADRs of digoxin?
Nausea, vomiting, xanthopsia, brady/tachycardia, arrhythmias (VT and VF).
‘Reverse tick’ appearance on lateral leads (ST).
A yellow halo around objects.
What is the treatment of digotoxin?
Stop digoxin (long half-life).
If levels are high, and arrhythmia risk is high - Digibind (an immune antibody that binds with digoxin and is excreted in urine).
What is adenosine?
Binds to adenosine receptors on the AVN and slows conduction.
Converts paroxysmal SVT to sinus rhythm - may cause asystole for a few seconds.
What are the indications for anticoagulation?
AF; risk of stroke or peripheral emboli (increases with age).
Metallic heart valves.
DVT/PE.
Prophylaxis - surgery, high risk medical patients, immobilisation.
What is CHADSVAS?
CHF (+1).
Hypertension (+1).
Age > 75yrs (+2).
Diabetes (+1).
Stroke/TIA/VTE (+2).
Vascular disease (+1).
Age 65-74 (+1).
Sex (female) (+1).
What are the ideal characteristics of anticoagulants?
Oral.
No need for monitoring.
No interaction with food or drugs.
Given once or twice a day, at a fixed dose irrespective of body weight or age.
As effective or safer than warfarin.
What are examples of oral anticoagulants?
Vitamin K antagonist (Warfarin)
Direct thrombin inhibitor (Dabigatran).
Direct Xa inhibitors (Rivaroxaban, Apixaban, Edoxaban).
