CV arrythmias Flashcards
ectopic beats compared to AF are often spontanoeous and resolve on their own
if tx is needed what drug class used?
beta blocker
AF tx aims to do what 2?
reduce symptoms and prevent complications, especially stroke
what is a stroke
blood doesn’t fully eject –> clot
blood pools in valve/ chambers -> clot and stroke risk
af managed through what 2?
ventricular rate control or sinus rhythm control
2 types of pts who may have AF acute
pt with or without life-threatening haemodynamic instability
treatment for pt with life-threatening haemodynamic instability caused by AF?
Emergency electrical cardioversion without delay to achieve anticoagulation!
prevents clotting
treatment for patients without life-threatening haemodynamic instability
Onset of AF <48 hours?
Onset of AF >48 hours?
Onset of AF <48 hours? Rate or Rhythm control
Onset of AF >48 hours? Rate control
what is meant by
rate control
rhythm control
rate: via medication
rhythm: cardioversion
2 Types of (Cardioversion) Rhythm Control to restore sinus rhythm?
Pharmacological
Electrical
pharmacological rhythm control examples 2
flecainide or amiodarone
electrical rhythm control examples?
start IV anticoagulation (heparin) and rule out a left atrial thrombus
3 Types of (ventricular) Rate Control Monotherapy?
this is preferred first line for AF except in pts with new onset
beta-blocker (not sotalol)
Rate-limiting CCB- verapamil/diltiazem
Digoxin (mainly sedentary patients with non-paroxysmal AF)
Choice of drug should be based on what?
individual symptoms
HR
comorbidities
patient preference
if monotherapy to control ventricular rate fails, what to do?
dual therapy:
combine any 2: beta blocker/digoxin/diltiazem
if symptoms not controlled w dual therapy, consider rhythm control and if LVEF < 40%, combine what 2 drugs?
bb and digoxin
AF maintenance,
if AF present > 48hrs, pt must be fully anticoaged for min 3 weeks and continue oral anticoag at least X after cardioversion
4 weeks
drugs tx usign what may be required post cardioversion?
standard bb
if symptoms persist or bb not appropriate: SPAF: sotalol, propadenone, amiodarone, or flecainide
whats paroxysmal AF?
paroxysmal: sudden attack/ increase insymptoms of diease
AF: irregular heart rhythm sudden and goes on its own
pill in pocket approach used to restore sinus rhythm what is this
take a tablet: flecainide or propadenone on onset of AF episode
ALL pts with AF should be assessed for stroke risk and thromboprophylaxis need balanced with risk of bleeding
using what tools?
stroke: CHA2DS2-VASc
bleeding risk: ORBIT
what does CHA2DS2-VASc consider?
Congestive HF
Hypertension
Age 75+ (2)
Diabetic
Stroke/TIA (2)
Vascular disease- DVT, aneurysm, etc
Age 65-74
Sex- female
When is thromboprophylaxis NOT needed? chadsvasc
Men= 0
Women= 1
needed if men: 1 and women: 2
thromboprophylaxis done with what 2 drugs?
Warfarin (vit K antagonist)
OR DOACs in non-valvular AF
name of condition described:
abnormal heart rhythm occurring in upper chambers of heart (atria). rapid, regular heartbeat
atrial flutter
Atrial flutter tx options same as af but responds better to which: electrical cardioversion or drug tx?
electrical
rate control of atrial flutter is normally temporary until sinus rhythm restored
name 2 possible classes of rate control drugs used
bb or RL CCBs
t/f paroxysmal supraventricular tachycardia usually goes away on tis own without tx
true
if paroxysmal supraventricular tachycardia requires tx, reflex vagal stimulation may be needed which involves what procedures?
stimulate vagus nerve:
- Valsalva manoeuvre, immerse face in ice-cold water, or carotid sinus massage
vagus nerve stim procedures should be performed with what monitoring?
ECG monitoring
if reflex vagal stim doesnt work, how is paroxysmal supraventricular tachycardia treated
a. iv adenosine
b. ineffective, give iv verapamil
Recurrent episodes of paroxysmal supraventricular tachycardia can be treated by what
catheter ablation,
or prevented with BBs or RL CCBS: diltiazem, verapamil, sotalol, flecainide, propafenone
Arrhythmias after myocardial infarction: how is bradycardia treated?
particularly if complicated by hypotension, IV atropine
Pulseless ventricular tachycardia or ventricular fibrillation require what?
very bad arrhythmias… resuscitation
pts with UNSTABLE or STABLE ventricular tachyardia tx with:
direct current cardioversion
if fails, iv amiodarone
repeat current cardioversion
unstable
pts with UNSTABLE or STABLE ventricular tachyardia tx with:
iv amiodarone
direct current cardioversion
non-sustained ventricular tachycardia can be treated with bb
stable
pts at high risk of cardiac arrest need maintenance therapy through what
- implantable cardioverter defibrillator
- can add bb/ amiodarone (in combo with standard bb)
what is Torsade de pointes
form of ventricular tachycardia associated with a long QT syndrome
long QT syndrome/ torsade can be drug induced OR caused by what 3 factors
hypokalaemia, severe bradycardia, and genetic predisposition
what drugs can cause hypOkalaemia
amiodarone
sotalol
macrolides
haloperidol
ssris
tcas
antifungals
torsade usually self limiting but can be recurrent leading to what
impaired consciousness
if torsade not controlled -> ventricular fibrillation –> death
torsade treated how
iv magnesium sulphate
bb NOT sotalol and atrial/ ventricular pacing may be considered
why should Anti-arrhythmics NOT be used in torsade?
can prolong QT interval more -> worsen condition
Anti-arrhythmic drugs can be classified clinically into those that act on
- supraventricular arrhythmias (e.g. A),
- ventricular arrhythmias (e.g. B)
- both supraventricular and ventricular arrhythmias (e.g. C)
A. verapamil
B. lidocaine
C. amiodarone
Anti-arrhythmic drugs can also be classified by effects on electrical behaviour of myocardial cells during activity (the Vaughan Williams classification)
less important
Class I: membrane stabilising drugs (e.g. lidocaine, flecainide)
Class II: beta-blockers
Class III: amiodarone; sotalol (also Class II)
Class IV: calcium-channel blockers (includes verapamil but not dihydropyridines)
hypokalaemia enhances the arrhythmogenic (X) effect of many drugs.
pro-arrhythmic
due caution
amiodarone is a high risk drug with very long half life
should be avoided in what 2 circumstances
bradycardia and heart block
bc as a side effect it can slow down HR
6 main SEs of amiodarone
TCP PHD
thyroid disorders
corneal microdeposits
photosensitivity reaction
pulmonary tox
hepatotoxicity
driving and skilled tasks
what is meant by corneal microdeposits
as a SE of amiodarone
pt dazzled by headlights of oncoming traffic
reversible when tx ends
if vision impaired: STOP
amiodarone contains iodine so affects what function?
thyroid
can cause hypo or hyeprthyroidism
treated w levothyroxine
how to treat photosensitivity reaction as SE of amiodarone
avoid sunlight
use sunscreen for months after tx end
what other drugs cause photosensitivity reaction? SAN LIGHT
sulfonamides
amiodarone
nsaids
loop diuretics
isotretinoin
griseofulvin
hydro–terzole
tetracycline
amiodarone loading dose
200mg TDS 7 days
200mg BD 7 days
200mg OD maintenance
how may SE pulmonary tox be observed w amiodarone use
report new/ progressive SOB or cough
hepatotox SE of amiodarone. stop if pt develops liver disease, how may this be noticed?
dark urine
jaundice
abdominal pain
nausea vom
light colour stools
pruritis
why should you HALVE dose of digoxin when using amiodarone alongside it?
amiodarone: enzyme inhibitor
why could effects and interactions of amiodarone last for several weeks/ months
very long t1/2
what 4 main types of drugs can amiodarone interact with
- drugs causing hypokalaemia bc amiodarone does too
- drugs causing QT prolongation
- cyp450 enzyme substrates
- drugs causing bradycardia
what drugs may cause QT prolongation thus interact with amiodarone
macrolides
quinolones
ssris
antipsychotics
ondansetron
emiodarone is cyp450 inhibitor so other enzyme inhibitors and inducers affect it too eg
inhib grapefruit
warfarin
contraceptives
statin
inducer phenytoin, phenobarb
what drugs can cause bradycardia thus interact w amiodarone
bb
rl ccbs
digoxin
what to monitor with amiodarone use?
TLP-XE
thyroid function
liver function
Potassium
chest XRay
annual Eye exam
how often to do thyroid and liver func tests with amiodarone
before tx then every 6 months
when to do serum potassium and chest x ray w amiodarone tx
once before tx
why are potassium and chest x ray done on amiodarone tx
causes hypokalaemia
due to pulmonary effects, rule out existing lung conditions
what to monitor with IV amiodarone?
ecg and liver transaminases
MHRA warning
pts who have stopped amiodarone in last few months and need to start sofosbuvir and daclatasvir, simeprevir and sofosbuvir, or sofosbuvir and ledipasvir should be monitored why?
risk of severe heart blokc - fatal!
digoxin therapeutic range?
0.7-2.0 ng/mL
when is there a toxicity risk in dogoxin conc and how is this treated?
Increased from 1.5-3.0 ng/mL.
Treated with digoxin-specific antibody
signs of digoxin tox?
SICK AND SLOW
D&V
SA/AV block+bradycardia
Dizziness/confusion/depression
Blurred/yellow vision
when do you take blood samples with digoxin
6-12 hrs after a dose
what 2 to monitor with digoxin
serum elecs and renal function
digoxin interactions?
BTHC
bb
TCA
hypokalaemia drugs - risk of dig tox
cyp450 enz inducers/ inhibitors
why do bb interact w digoxin
increase AV block risk and increases plasma concs
why do TCAs interact w digoxin
can induce arrhythmias
if we’re treating arrythmias no point giving drug than induces them!
how do cyp450 enz inducers and inhibitors each affect digoxin plasma conc?
inducer: reduces conc
inhibitor: increases conc
which following SEs is least associated with amiodarone?
hyperthyroidism
renal failure
pulmonary tox
photosensitivity
blurred vision
renal failure
adenosine used for terminating paroxysmal supraventricular arryhmias and SEs short lived why
short duration of action
t1/2 only 8-10 secs but prolonged in px taking dipyridamole
unlike X, adenosine can be used after a bb but X may be better than adenosine in asthma
verapamil
digoxin belongs to class X and slows ventricular response in AF and flutter
cardiac glycoside
what may occur with large doses of verapamil
hypotension
iv verapamil may be followed by oral tx but whats a serious DDI with iv verapamil?
bb
iv bb eg X or Y can be used for rapid control of ventricular rate
emolol or propamolol
Supraventricular arrhythmias 4 main drugs
adneosin
digoxin
verapamil
bbs
Drugs for both supraventricular and ventricular arrhythmias include what?
amiodarone,
beta-blockers,
disopyramide,
flecainide acetate,
procainamide (available from ‘special-order’ manufacturers or specialist importing companies),
propafenone hydrochloride.
how do bb act an anti-arrhythmic drugs?
attenuating the effects of the sympathetic system on automaticity and conductivity within the heart.
what drug can be used for life threatening ventricular arrythmias?
and which is normally used?
normally: lidocaine IV but no longer first choice
serious: mexiletine
