AF / SVT / VTACH / ALS Flashcards
etiology of atrial flutter or atrial fibirllation
HTN
HEART FAILURE
DIABETES
HYPERTHYROIDISM
COPD
OSA
alcohol
infection
Atrial fibrillation when to start rate control and what is used for rate control?
start rate control if it is more than 48 hours or duration uncertain
chronic AF - hard to convert to sinus
if there is a reversible cause
heart failure primarily caused by AF
A beta-blocker or a rate-limiting calcium channel blocker (e.g. diltiazem) is used first-line to control the rate in AF.
If one drug does not control the rate adequately NICE recommend combination therapy with any 2 of the following:
a betablocker
diltiazem
digoxin
Atrial fibrillation rhythm control ?
patient switches from AF to sinus rhythm presents the highest risk for embolism leading to stroke
For this reason patients must either have had a short duration of symptoms (less than 48 hours) or be anticoagulated for a period of time prior to attempting cardioversion
electrical cardioversion as an emergency if the patient is haemodynamically unstable
electrical or pharmacological cardioversion as an elective procedure where a rhythm control strategy is preferred.
Electrical cardioversion is synchronised to the R wave
Onset < 48 hours rhythm control
if less than 48 hours onset patients heparin before the procedure to cover any potential risk during the first 24 hours
patients may be cardioverted using either:
electrical - ‘DC cardioversion’
pharmacology - amiodarone if structural heart disease,
flecainide or amiodarone in those without structural heart disease
Following cardioversion if AF is confirmed as being less than 48 hours duration then further anticoagulation is unnecessary
however Patients who have risk factors for ischaemic stroke should be put on lifelong oral anticoagulation.
AF Onset > 48 hours rhythm control
anticoagulation should be given for at least 3 weeks prior to cardioversion.
An alternative strategy is to perform a transoesophageal echo (TOE) to exclude a left atrial appendage (LAA) thrombus. If excluded patients may be heparinised and cardioverted immediately.
NICE recommend electrical cardioversion in this scenario, rather than pharmacological.
If there is a high risk of cardioversion failure (e.g. Previous failure or AF recurrence) then it is recommend to have at least 4 weeks amiodarone or sotalol prior to electrical cardioversion
Following electrical cardioversion patients should be anticoagulated for at least 4 weeks. After this time decisions about anticoagulation should be taken on an individual basis depending on the risk of recurrence and using CHADVASC score
Agents used to maintain sinus rhythm in patients with a history of atrial fibrillation
dronedarone: second-line in patients following cardioversion
amiodarone: particularly if coexisting heart failure
flecanide
propafenone
catheter ablation in AF
catheter ablation for those with AF who have not responded to treatmnet and have peristant AF or wish to avoid, antiarrhythmic medication.
Anticoagulation
should be used 4 weeks before procedure
catheter ablation controls the rhythm but does not reduce the stroke risk, even if patients remain in sinus rhythm. Therefore, patients still require anticoagulation as per their CHA2DS2-VASc score
if score = 0: 2 months anticoagulation recommended
if score > 1: longterm anticoagulation recommended
50% of patients experience an early recurrence (within 3 months) of AF that often resolves spontaneously
CHADVASC score interpretation ?
if a CHA2DS2-VASc score suggests no need for anticoagulation it is important to ensure a transthoracic echocardiogram has been done to exclude valvular heart disease, which in combination with AF is an absolute indication for anticoagulation
0 = no treatment
1 Males: Consider anticoagulation
Females: No treatment (this is because their score of 1 is only reached due to their gender)
2 or more Offer anticoagulation
causes of SVT
alcohol
caffeine
heart failure
IHD
hyperthyroidism
cocaine and methamphetamine
electrolyte imabalnce - in potassium , magneiusm and calcium (hypo)
COPD /PE
valcular heart diseases
Management for SVT ?
acute -
* Hypotension: BP ≤90mmHg * Heart failure
* Impaired consciousness
* Heart rate ≥200
hemodynamically unstable : sedation then up to 3 synchronised
electrical cardioversion
then amiodarone 300mg SAT (over 20mins)
followed by 900mg
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non acute
vagal manoeuvres:
Valsalva manoeuvre: e.g. trying to blow into an empty plastic syringe
carotid sinus massage
intravenous adenosine
rapid IV bolus of 6mg → if unsuccessful give 12 mg after 1-2 mins → if unsuccessful give further 18 mg
contraindicated in asthmatics - verapamil is a preferable option
3rd line - amiodarone or flecanide (used in caution with structural heart disease)
electrical cardioversion
Prevention of SVT?
teach valsalva - if the burden of SVT is low
if no pre-excitation -
Beta-blockers (e.g., metoprolol, atenolol) - infective in predication
or calcium channel blockers (e.g., verapamil, diltiazem) - contraindicated in pre-exciation
Flecainide or propafenone may be used in patients with paroxysmal SVT who fail to respond to first-line treatments.
3rd line - amiodarone esp if structural heart disease present
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if there is pre-excitation (WPW) = flecanide
amiodarone / sotalol (if no structural heart disease)
CONTRAINDICATED in pre-excitation is- DIGOXIN
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Catheter ablation can be a curative treatment for recurrent or persistent SVT
causes of VT ?
ihd
cardiomyopathy
prolonged QT interval:
Congenital: Jervell-Lange-Nielsen syndrome
Romano-Ward syndrome
Drugs: amiodarone,
sotalol
tricyclic antidepressants,
fluoxetine
chloroquine
terfenadine
erythromycin
other :
electrolyte: hypocalcaemia, hypokalaemia, hypomagnesaemia
acute myocardial infarction
myocarditis
hypothermia
MX of ventricular tachycardia ?
if the patient has adverse signs
(systolic BP < 90 mmHg, chest pain, heart failure, ) then immediate
up to 3 synchronised electrical cardioversion is indicated
then amiodarone 300mg over 20 mins
and 900 mg over 24 hours
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witnessed VF or pulsless VT in coronary unit
shout for help / call 2222
give three stacked shocks - which counts as first shock
and follow ALS protocol - of CPR
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if hemodynamically stable
amiodarone: ideally administered through a central line (to r/o phlebitis)
lidocaine: use with caution in severe left ventricular impairment
procainamide
VERAPAMIL CONTRAINDICATED
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if drug therapy fails = ICD
patinet might also need ICD in severe impaiment in lung function
