1. Paroxysmal : stop within 48h w/o tx 2. Persistent : lasts >7 days 3. Permanent : present all time

Arrhythmias Flashcards by Izy Mal

Ectopic beats

spontaneous + pt has normal heart
IF troublesome = beta-blocker sometimes effective

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Atrial fibrillation ~ acute presentation

In patients presenting acutely but without life-threatening haemodynamic instability, rate or rhythm control given onset of arrhythmia <48 hours; rate control preferred if onset >48 hours or uncertain. If urgent rate control required, beta-blocker IV; rate-limiting CCB (verapamil) (if left ventricular ejection fraction (LVEF) ≥40%) be given. In patients with suspected concomitant acute decompensated HF, CCB AVOID

— If pharmacological cardioversion agreed, flecainide (if no structural or ischaemic heart disease present) or amiodarone hydrochloride used

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Cardioversion

Sinus rhythm restored by electrical cardioversion or pharmacological (anti-arrhythmic drug (flecainide / amiodarone).
~ If >48 hours, electrical cardioversion, but delayed until fully anticoagulated for at least 3 weeks. If not possible, left atrial thrombus ruled out & parenteral anticoagulation (heparin) immediately before cardioversion; oral anticoagulation given after cardioversion + continued for at least 4 weeks
~ During period prior to cardioversion, offer rate control.
~ Amiodarone started 4 weeks before & continued for up to 12 months after electrical cardioversion to maintain sinus rhythm

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Rate control in AF

Ventricular rate ~ controlled with standard beta-blocker (NOT sotalol hydrochloride), or with rate-limiting CCB (diltiazem hydrochloride [unlicensed indication] / verapamil as monotherapy)

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Digoxin in AF

monotherapy ONLY given for initial rate control in patients with non-paroxysmal atrial fibrillation who predominantly sedentary, or in if rate-limiting drugs unsuitable

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Ventricular arrhythmias management

IV lidocaine for ventricular tachycardia or ventricular fibrillation & pulseless ventricular tachycardia in cardiac arrest refractory to defibrillation, but no longer anti-arrhythmic drug of first choice.

Drugs for both supraventricular & ventricular arrhythmias = amiodarone, BB, disopyramide, flecainide, procainamide & propafenone

Mexiletine = tx of life-threatening ventricular arrhythmias

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Amiodarone

~ tx of arrhythmias, if other drugs ineffective or contraindicated
~ used for paroxysmal supraventricular, nodal & ventricular tachycardias, atrial fibrillation and flutter, & ventricular fibrillation
~ used for tachyarrhythmias associated with Wolff-Parkinson-White syndrome
~ ONLY start under hospital or specialist supervision
~ can be given by IV infusion & PO , + has advantage of causing little or no myocardial depression
~ very long half life

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Anti-arrhythmic drugs Class I

Na+ blockers
1~ disopyramide
2~ Lidocaine
3~ Flecainide / Propafenone (contraindicated in asthma / severe COPD / Avoid in structural / ischaemic heart disease)

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Anti-arrhythmic drugs Class II

Beta blockers
~ Propranolol

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Anti-arrhythmic drugs Class III

K+ channel blockers
~ Amiodarone (4 weeks before & 12 months after electrical cardioversion)
~ Sotalol
~ Dronedarone (hepatoxicity & HF side effects)

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Anti-arrhythmic drugs Class IV

Calcium channel blockers
~ Verapamil
~ Diltiazem (unlicensed)

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Anti-arrhythmic drugs Class other

~ Adenosine
~ Digoxin (effective in sedentary pt with non-paroxysmal AF or in associative CHF)

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What is AF ?

abnormal, disorganised electrical signals fired as atria quiver / fibrillate = rapid/irregular heartbeat

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AF symptoms

~ heart palpitations = pounding / fluttering
~ dizziness, SOB, tiredness

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2 main complications of AF

Stroke & HF

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3 types of AF

Paroxysmal : stop within 48h w/o tx
Persistent : lasts >7 days
Permanent : present all time

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Rate control in AF

controls ventricular rate

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Rhythm control in AF

cardioversion (restores sinus rhythm)
1. electrical = direct current
2. Pharmacological = anti-arrhythmic

==> cannot give if symptoms >48h; increased stroke risk
==> electrical preferred if >48h

~ wait until fully anti-coagulated for 3 weeks before cardioversion & cont. 4 weeks after
~ if haemodynamically unstable = electrical cardioversion; give parenteral anti-coagulant (heparin) & rule out atrial thrombus before

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acute new-onset of AF

~ life-threatening haemodynamic instability = electrical cardioversion
~ W/O life-threatening haemodynamic instability
— <48h = rate/rhythm control (electrical or amiodarone/flecainide
—>48h = rate control (verapamil, beta blocker)

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AF maintenance drug tx

1st line = rate control
~~~ Beta blocker ( NOT sotalol), rate-limiting CCb, digoxin

2nd line = rhythm control
~~~ beta-blocker or oral anti-arrhythmic
e.g. Sotalol, Amiodarone, Flecainide, Propafenone, Dronedarone

paroxysmal or symptomatic AF

~ Ventricular or rhythm control
== beta-blocker or anti-arrhythmias

~ Pill in pocket if infrequent episodes - self tx
== Flecainide or Propafenone = restores sinus rhythm if episode occurs

Stroke prevention in AF

give anti-coagulants if stroke risk > risk of bleed (HAS-BLED)

Risk of stroke CHA2DSVAS tool

C = CHF, left ventricular dysfunction
H = HTN
A2 = 75+
D = DM
S2 = stroke/TIA/VTE hx
V = vascular disease
A = 65-74
Sc = sex i.e. female / male

IF 2 or more = anticoagulant
Male = 0
Female = 1

new-onset AF

Parenteral anticoagulants (Heparin)

Diagnosed AF tx

1. Warfarin OR 2. NOAC (in non-valvular AF + >1 risk factor of 75+, HF, HTN, DM, Hx stroke or TIA)

Ventricular tachycardia (arrhythmias) ~ pulseless / fibrillation tx

immediate defib + CPR .. IV amiodarone if not working 2. Unstable sustained ventricular tachycardia

Ventricular tachycardia (arrhythmias) ~ unstable sustained tx

direct current cardioversion IV amiodarone & repeat direct current

Ventricular tachycardia (arrhythmias) ~ Stable sustained tx

IV anti-arrhythmic (amiodarone)

Ventricular tachycardia (arrhythmias) ~ non- sustained tx

Beta blockers

Torsades de pointes (QT prolongation) rx

Magnesium sulphate IV

Torsades de pointes (QT prolongation) causes

~ Sotalol ~ other drugs that prolong QT intervals ~ HyPOkalaemia ~ Bradycardia

paroxysmal supraventricular tachycardia

1. Terminates spontaneously or with reflex vagal nerve stimulation e.g. Valsalva, carotid sinus massage, face in cold water 2. IV Adenosine (contra in COPD/Asthma) 3. IV verapamil if unstable = direct current conversion Recurrent = catheter ablation or verapamil/diltiazem/flecainide/propafenone)

Amiodarone class

Class III anti-arrhythmic used in ventricular arrhythmias

Amoidarone dose

Initial loading dose 1. 200mg TDS 7/7 2. 200mg BD 7/7 3. 200mg OD as maintenance

Amiodarone SEs & counselling points ~ EYES

Corneal micro-deposits pt counsel: night-time glares when driving Optic neuropathy / neuritis (blindness) pt counsel: STOP if vision impaired

Amiodarone SEs & counselling points ~ SKIN

Phototoxicity (burning, erythema) Slate-grey skin pt counsel: shield skin from light, use sunscreen for months after stopping

Amiodarone SEs & counselling points ~ NERVES

Peripheral neuropathy pt counsel: numbness, tingling hands/feet, tremors

Amiodarone SEs & counselling points ~ LUNGS

1. Pneumonitis 2. Pulmonary fibrosis pt counsel: SOB, dry cough

Amiodarone SEs & counselling points ~ LIVER

Hepatotoxic Pt counsel: report jaundice, N, V, Malaise, Itching, abdo pain, bruising, x3 raised liver transaminase

Amiodarone SEs & counselling points ~ THYROID

amiodarone has iodine ~ Hyperthyroidism (weight loss, heat intolerance, tachycardic).... give carbamazepine, STOP amiodarone ~ Hypothyroidism (weight gain, cold intolerance, bradycardic)... give levothyroxine but cont. amiodarone

Amiodarone monitoring

1. Annual eye test 2. CXR before tx 3. LFTs every 6/12 4. Monitor TSH, T3, T4 before tx + every 6/12 5. BP, ECG ( causes hypotension & bradycardia) 6. Serum K (causes HYPOkalaemia)

Amiodarone interactions

~ LONG half life ~ 50 days 1. Grapefruit juice (Enzyme inhibitor) = increased plasma amiodarone conc. 2. Amiodarone = enzyme inhibitor - Warfarin, Phenytoin, Digoxin (half dose) 3. Increased myopathy - Statins 4. Bradycardia, AV block, & myocardial depression -- Beta blockers, CCD (verapamil, diltiazem) 5. QT prolongation = increased risk of ventricular arrhythmia e.g. Quinolones, Macrolides, TCA, SSRI, Lithium, Quinine, Hydrochloroquine, Anti-malaria, APs (sulpiride, pimozide, amisulpride )

Digxoin MOA

cardiac glycoside ~ high risk increases force of myocardial contraction (POSITIVE inotrope) + reduces conductivity in AV node

Digoxin therapeutic levels

1-2 mcg/L (6 hours after dose) ~ renally cleared so more caution in impairment

Digoxin doses & bioavailability

~ loading dose needed as LONG half-life AF = 125-250mcg HF (sinus) = 62.5-125mcg ~ Bioavailability --- Elixir = 75% --- Tabs = 90% --- IV = 100%

Digoxin toxicity signs

"SLOW & SICK" Hypo-kalaemia Hypo-magnesia Hypo-calcemia Hypoxic Renal impairment => ~ Bradycardia / Heart block ~ N, V, D, Abdo pain ~ Blurred/ Yellow vision ~ Confusion, delirium ~ Rash

Digoxin toxicity tx

withdraw, correct electrolyte imbalance ~ Digifab = digoxin-specific antibody if unresponsive to atoprine

Digoxin interactions

1. Hypo-kalaemia --- Diuretics (loop/thiazides), B2 agonist, Steroids, Theophylline) 2. Increase digoxin con = toxic -- Amiodarone, CCB, Macrolides, Ciclosporins (enzyme inhibitors) 3. Decreases digoxin conc. -- St John wort, Rifampicin (inducers) 4. Reduced renal excretion = toxic as digoxin renally excreted -- NSAIDs, ACE inhibitors / ARBs

Digoxin interaction mnemonic

CRASED C = CCB (Verapamil) R = Rifampicin A = Amiodarone S = St Johns Wort E = erythromycin D = diuretics