Arrythmia Flashcards
What is the most common sustained cardiac arrhythmia?
Atrial fibrillation (AF) It is very common, being present in around 5% of patients over aged 70-75 years and 10% of patients aged 80-85 years
What is the most important important aspect of managing patients with Atrial Fibrillation?
educing the increased risk of stroke which is present in these patients.
What can uncontrolled atrial fibrillation can result in?
symptomatic palpitations and inefficient cardiac function
What are the types of atrial fibrillation?
first detected episode (irrespective of whether it is symptomatic or self-terminating)
recurrent episodes, when a patient has 2 or more episodes of AF.
in permanent AF there is continuous atrial fibrillation which cannot be cardioverted or if attempts to do so are deemed inappropriate.
What are the two types of recurrent atrial fibrillation?
PAROXYSMAL: If episodes of AF terminate spontaneously then the term paroxysmal AF is used. Such episodes last less than 7 days (typically < 24 hours).
PERSISTENT: If the arrhythmia is not self-terminating then the term persistent AF is used. Such episodes usually last greater than 7 days
What are the treatment goals of permanent AF?
Treatment goals are therefore rate control and anticoagulation if appropriate
What are the Symptoms and signs of AF?
Symptoms
palpitations
dyspnoea
chest pain
Signs
an irregularly irregular pulse
What other conditions (other than AF) can give you an irregular pulse?
ventricular ectopics or sinus arrhythmia.
What investigation is essential for diagnosis of AF?
ECG
What are the two key parts of managing patients with AF?
- Rate/rhythm control
- Reducing stroke risk
rate control: accept that the pulse will be irregular, but slow the rate down to avoid negative effects on cardiac function
rhythm control: try to get the patient back into, and maintain, normal sinus rhythm. This is termed cardioversion. Drugs (pharmacological cardioversion) and synchronised DC electrical shocks (electrical cardioversion) may be used for this purpose
For many years the predominant approach was to try and maintain a patient in sinus rhythm. This approach changed in the early 2000’s and now the majority of patients are managed with a rate control strategy.
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For AF NICE advocate using a rate control strategy except in a number of specific situations such as?
coexistent heart failure, first onset AF or where there is an obvious reversible cause.
Other patients may have had a rate control strategy initially but switch to rhythm control if symptoms/heart rate fails to settle.
What medications are used for rate control in 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
In cardioversion, the moment a patient switches from AF to sinus rhythm presents the highest risk for embolism leading to stroke.
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Why must patients either have had a short duration of symptoms (less than 48 hours) or be anticoagulated for a period of time prior to attempting cardioversion?
In cardioversion, the moment a patient switches from AF to sinus rhythm presents the highest risk for embolism leading to stroke.
How do clinicians identify the most appropriate anticoagulation strategy for reducing stroke risn in AF?
CHA2DS2-VASc
What does CHA2DS2VasC consist of?
C Congestive heart failure 1 H Hypertension (or treated hypertension) 1 A2 Age >= 75 years 2 Age 65-74 years 1 D Diabetes 1 S2 Prior Stroke or TIA 2 V Vascular disease (including ischaemic heart disease and peripheral arterial disease) 1 S Sex (female) 1
What is the suggested anticoagulation strategy based on the CHA2DS2-VASc score?
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
What is a common contraindication for beta-blockers
asthma
For rate control in AF which medication is the preferred choice if the patient has coexistent heart failure?
Digoxin
not considered first-line anymore as they are less effective at controlling the heart rate during exercise
What other Agents used to maintain sinus rhythm in patients with a history of atrial fibrillation?
sotalol
amiodarone
flecainide
What are the Factors favouring rate control in AF?
Older than 65 years
History of ischaemic heart disease
What are the Factors favouring rhythm control in AF?
Younger than 65 years Symptomatic First presentation Lone AF or AF secondary to a corrected precipitant (e.g. Alcohol) Congestive heart failure
NICE recommends the use of catheter ablation for those with AF who?
have not responded to or wish to avoid, antiarrhythmic medication.
What are the Technical aspects of Catheter ablation?
the aim is to ablate the faulty electrical pathways that are resulting in atrial fibrillation. This is typically due to aberrant electrical activity between the pulmonary veins and left atrium
the procedure is performed percutaneously, typically via the groin
both radiofrequency (uses heat generated from medium frequency alternating current) and cryotherapy can be used to ablate the tissue
When should anticoagulation be started for patients undergoing catheter ablation for AF?
Anticoagulation should be used 4 weeks before and during the procedure
Therefore, patients still require anticoagulation
afterwards as per there CHA2DS2-VASc score
if score = 0: 2 months anticoagulation recommended
if score > 1: longterm anticoagulation recommended
What are the complications of catheter ablation?
cardiac tamponade
stroke
pulmonary valve stenosis
What is the success rate of catheter ablation?
around 50% of patients experience an early recurrence (within 3 months) of AF that often resolves spontaneously
longer term, after 3 years, around 55% of patients who’ve had a single procedure remain in sinus rhythm. Of patient who’ve undergone multiple procedures around 80% are in sinus rhythm
When would cardioversion be used in atrial fibrillation?
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 to prevent delivery of a shock during the vulnerable period of cardiac repolarisation when ventricular fibrillation can be induced.
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In terms of cardioversion If the atrial fibrillation is definitely of less than 48 hours onset patients should be?
Put on Heparin.
Patients who have risk factors for ischaemic stroke should be put on lifelong oral anticoagulation.
They may be cardioverted electrically or pharmalogically.
Following electrical cardioversion if AF is confirmed as being less than 48 hours duration then further anticoagulation is?
unnecessary
If the patient has been in AF for more than 48 hours then anticoagulation should be given when?
What is an alternative?
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.
If onset of AF >48 hours NICE recommend which cardioversion?
electrical
What suggests a high risk of cardioversion failure?
Previous failure or AF recurrence
If onset of AF >48 hours & If there is a high risk of cardioversion failure then it is reccomended to have what.
4 weeks amiodarone or sotalol prior to electrical cardioversion