Cardiac - Arrhythmias Flashcards
what are the class I anti-arrhythmic drugs and give 4 examples.
- membrane stabilising drugs; Na+ blockers
- lidocaine
- Disopyramide
- Flecainide/Porpafenone
what are the contraindications for flecainide/propafenone? (class I)
asthma / severe COPD
avoid in heart disease
what class of drugs belong to the class II anti arrhythmics?
beta blockers e.g., propranolol
what type of drugs are class III anti arrhythmics?
give some examples
K+ channel blockers
e.g., amiodarone
sotalol
dreonedrone
how many months before and after cardioversion should amidoarone be given to increase success.
4 weeks before and 12 months after
what class III anti arrythmic has SE of hepatotoxicity and heart failure SE?
dronedarone
what class of drugs belong to the class IV anti arrythmics?
give 2 examples
which one is unlicensed use?
rate limiting calcium channel blockers
e.g., verapamil, diltiazem
diltiazem is unlicensed
what other anti arrythmic drugs are there that don’t belong to a class?
adenosine and digoxin
in what type of patient is digoxin most effective in?
sedentary patients with non-paroxysmal AF and in patients with associated congestive heart failure
what are the 2 main complications of AF?
stroke and heart failure
whats the differernce between paroxysmal AF, persistent AF and permanent AF?
- paroxysmal: episodes stop within 48hrs without treatment
- persistnet AF: episode lasts >7 days
- Permanent AF: present all the time
what are the 2 focuses of treatment in AF?
- rate control
- sinus rhythm control
what does cardioversion mean and what are the 2 ways this can be achieved?
- means to restore sinus rhythm
- either electrical (give direct current) or pharmacological by giving anti-arrhythmic
why can’t you give management for cardioversion if symptoms >48 hours?
what is the preferred method if it has been >48hrs
due to increased risk of stroke
electrical is preferred if >48hrs
how long must someone be anticoaglated for before cardioversion?
how long must this continue post cardioversion?
need to be fully anticoagulated for 3 weeks before and continue 4 weeks after
what type of cardioverson can you give if the patient is haemodynamically unstable?
electrical - give parenteral anticoagulant and rule out left atrial thrombus
if a patient presents with new onset AF - what are the differences in management it they have life threatening haemodynamic instability and do not have life threatening haemodynamic instability?
If life-threatening = electrical cardioversion
without = <48hrs = rate or rhytham control (electrical or amiodarone/flecainide)
>48hrs = rate control (verapamil, beta blocker)
what are the first line options for maintence therapy in AF?
1st line = rate control
betablockers, rate limiting CCB, digoxin
what beta blocker can you not use for rate control in AF?
sotalol
what is the 2nd line in maintance therapy for AF?
2nd line = rhythm control
e.g., amiodarone, flecainide
what is the management for paroxysmal and symptomatic AF?
- ventricular or rhythm control = standard beta blocker or antiarrhythmic
- ‘pill in pocket’ if infreqeunt episodes = flecainide or propafenone to restore sinus rhythm
what must a persons CHADSVASC score be to qualify for anticoagulant?
2
not needed if low risk (male = 0 and females = 1)
what are the risk factors contributing to a raised CHADSVASC score?
- 75yrs +
- HF
- HTN
- diabetes
- previous stroke or TIA
what are ventricular arrhythmias?
when the heart beats too fast
what are the 4 different types of ventricular arrhythmias?
- pulseless or fibrilation
- unstable
- stable
- non-sustained
what is the management for pulseless arrhythmias?
immediate defibrilation and CPR
IV amiodarone is given refractory to defibrilation
whats the management for unstable ventricular tachycardia?
direct current cardioversion. If this fails give IV amiodarone
whats the management for stable ventricualr tachycardia?
IV anti-arrhythmic = amiodarone
whats the management for non-sustained tachycardia?
beta blocker
whats the treatment for torsade de pointes?
magnesium sulphate
what is torasde de pointes and what can cause it?
prolonged QT
caused by sotalol and other drugs that prolong QT interval, hypOkalaemia, and bradycardia
whats the loading dose for amiodarone?
200mg TDS 7/7
200mg BD 7/7
200mg OD as maintenance
what are the side effects of amiodarone ( N TELLS)
N - erves: peripheral neuropathy. Counsel on numbness and tingling hands
T -hyroid dysfunction (contains Iodine)
E - yes corneal micro depsoits, esnure to counsel patients on night time glares when driving
L - iver: cause hepatoxicity. Counsell on symptoms
L - ungs: pneumonitis, pulmonary fibrosis. Counsel on SOB, dry cough
S - kin: phototoxicity, slate grey skin. COunsel on using high SPF sun cream for months after stopping
does amiodarone cause hyper or hypo thyroid?
what’s the management?
can cause both.
hyper = carbimazole, withdraw amiodarone
hypo = start lebothyroxine, continue amiodarone if essential
what are the 6 monitoring requirements for amiodarone?
- annual eye test
- CXR before treatment
- LFTS every 6 months
- TSH, T3, T4 before treatment and every 6 months
- BP and ECG (bradycardia and hypotension)
- Serum K+ (causes hypokalaemia; enhances arrhythmogenic effect of amiodarone)
whats the half life of amidoarone?
50 days = danger of interactions several months after stopping
what are 5 interactions with amiodarone?
- increased plasma amiodarone with grapefruit juice
- amiodarone is an enzyme inhibitor = warfarin, phenytoin, digoxin (half dose)
- increased risk of myopathy with statins
- bradycardia, AV block with beta blockers, rate limiting CCBs
- QT prolongation = increased risk of ventricular arrhthmia (quionlones, macrolides, TCAs, SSRIs, lithium, antipsychotics)
whats the therapeutic range for digoxin?
1 - 2 mcg/l
how does digoxin work?
increases force of myocardial contraction and reduces conductivity in the AV node
how long after PO digoxin has been given can you measure the levels?
6 - 8 hours to allow for absorption
is regular digoxin monitoring required?
no unless suspected toxicity or in renal impairment
why does digoxin need a loading dose?
becuase it has a long half life
whats the maintenance dose for digoxin in non-paroxysmal AF and in severe heart failure?
AF = 125mcg - 250mcg
HF = 62.5mcg - 125mcg
what are the different bioavailabilities for oral, liquid and IV digoxin?
PO = 90%
liquid = 75%
IV = 100%
what factors increase the risk of digoxin toxicity?
hypO K+, Mg2+
Hyper Ca2+
hypoxia
renal impairment
what are the symptoms of digoxin toxicity?
“slow and sick”
- bradycardia/heart block
- nausea, vomitting and diarrhoea, abdo pain
- blurred or yellow visions (halos)
- confusion
- rash
how do you treat digoxin toxicity?
- withdraw digoxin and correct electrolyte imbalances
- digoxin-specific antibody for life threatening ventricular arrhythmias unresponsive to atropine
what are the main interactions with digoxin and what are the effects? (CRASED)
- Calcium channel blockers (verampamil) = increased plasma digoxin conc
- Rifampicin = decreased digoxin conc, enzyme inducer
- Amiodarone = increased plasma digoxin conc, enzyme inhibitor
- St Johns Wort = redcued digoxin, enzyme inducer
- Erythromycin = increased plasma conc, enzyme inhibitor
- Diuretics = hypokalaemia predisposes digoxin toxicicity
whats the risk of using digoxin and NSAIDs/ACE/ARBS together?
renal impairment = reduced renal excreation = toxicity
