CVS: Atrial Fibrillation Flashcards
What are the risk factors for AF?
- increasing age
- HTN
- obesity
- diabetes
- valve disease
- IHD
- Heart failure
- sleep apnoea
- alcohol
Who should AF be suspected in?
People with an irregular pulse +/- any of:
* SOB
* Palpitations
* chest pain
* syncope/presyncope
* Reduced ET, fatigue, polyuria
* TIA/stroke/HF
Suspect paroxysmal AF if symptoms episodic and last <48hrs
What are the ECG features of Atrial Flutter?
- differential for AFib
- ‘saw tooth’ baseline - most recognisable in II,III, aVF
- regular atrial activity at rate around 300bpm, transmitted to the ventricles at a fixed rate - causing HR of 75, 100, or 150 depending on A:V conduction ratio
Which investigations should be done in suspected AF?
- ECG
- FBC, U&E, TFT, BNP if signs of HF
What are the ECG features of AF?
- no p waves
- chaotic baseline
- irregular ventricular rate
- ventricular rate is often 160–180 bpm (can be lower esp. if asymptomatic)
- ventricular complexes look normal unless there is a ventricular conduction defect.
If ECG is normal in suspected AF what should be done?
- 24hr ECG - if suspected asymptomatic episodes (e.g incidental finding or irregular pulse), or symptomatic episodes <24hrs apart
- if symptomatic >24hrs apart - 5 day event recorder or 7 day holder monitor
Which patients with confirmed AF should have an ECHO?
- when considering electrical or pharmacological cardioversion
- suspected underlying HF or valve disease
- to help stroke risk stratification
What score is used to estimate stroke risk? What score means anticoagulation should be offered?
- CHA2DS2-VASc score
- anticoagulation should be offered to everyone with score of >=2
- anticoagulation should be considered in men with score of 1
Which score does NICE recommend to predict bleeding risk?
What score indicates, low, medium and high risk of bleeding?
- ORBIT score
- <=2 is low risk, 3 is medium risk, >=4 is high risk
- Should be used to identify reversible factors to lower the bleeding risk
What are the key indications for using warfarin for stroke prevention?
- significant renal impairment CrCl <30 (if CrCl 15-29 can have 2.5mg BD apixaban)
- mechanical heart valve
- Hx rheumatic heart disease
- extremes of body weight >120kg, <50kg
If onset of AF was within the last 48hrs, what are the treatment options?
- urgent admission if haemodynamic instability (rapid HR, Low BP, dizziness, chest pain, SOB)
- if no haemodynamic instability - refer for electrical/chemical cardioversion OR start rate control.
Rate control is the default treatment except for:
- new onset AF <48hrs -refer for electrical/chemical cardioversion
- reversible cause for AF (e.g chest infection) -refer for electrical/chemical cardioversion
- symptomatic flutter - amenable to ablation
- heart failure due to AF - refer for electrical/chemical cardioversion
What is first line rate control treatment for AF?
- b-blocker (other than sotalol) OR rate-limiting CCB
- digoxin is an alternative for non-paroxysmal AF if they are sedentary, or if the B-blocker and CCB are contraindicated.
- F/U <1 week to review symptoms, HR, BP
When should rhythm control be considered?
- symptomatic AF despite rate control
- will be started in secondary care
Who does ‘pill in pocket’ rhythm control suit?
infrequent paroxysmal AF without underlying structural or functional heart disease, without low BP or bradycardia.
e.g. flecainide, sotalol
What is cardioversion and who is it helpful for?
- longer term rhythm control
- achieved electrically or pharmacologically
- helpful if: persistent symptoms, acute onset AF, co-morbid disease where it is unclear whether symptoms are due to AF or another cause (e.g. SOB)
What are underlying causes of AF?
- cardiac: HTN, valve disease, HF, IHD. Need ECHO if suspecting valve disease or HF (refer cardio). WPW (refer cardio)
- Resp: chest infection, lung cancer (refer resp oncologist). Need CXR if suspected.
- systemic: excess alcohol, hyperthyroidism (refer endo), U&E depletion, infection, diabetes - consider need for bloods.
If cause detected - refer as needed / manage as able.
What is the first line anticoagulation?
- DOAC (apixaban, dabigatran, edoxaban, rivaroxaban)
Warfarin 2nd line - if DOAC contraindicated, not tolerated
When is cardiology referral indicated (also on other cards)?
- suspected AF but not caught on ECG - for ambulatory monitoring
- confirmed or suspected HF, or valve disease
- paroxysmal AF, not responding to rate control (ablation or rhythm control may be needed)
- remain symptomatic despite adequate rate/ rhythm control - cardioversion may be needed
- high stroke risk not able to take anticoagulation - left atrial appendage occlusion device may be needed
What are the Group 1 and Group 2 DVLA rules for driving with AF?
- stop driving if arrhythmia has caused or likely to cause incapacity. Can drive again when underlying cause identified and controlled for >=4 weeks. No need to notify DVLA unless distracting or disabling symptoms
- disqualified from driving if arrhythmia has caused or likely to cause incapacity. May resume when arrhythmia controlled for >=3months, LVEF >=40%, no other disqualifying condition.
If a persons symptoms/HR not controlled on 1st line rate control, what should be done?
- increase dose
- if on max dose - combination treatment: Bblocker and digoxin
- if not controlled on combo treatment - refer <4weeks to cardio
What is the target INR for warfarin in AF?
2-3
How often should INR be monitored when initiating warfarin?
- daily until in therapeutic range on 2 consecutive occasions
- then twice weekly for 2 weeks
- then weekly until two readings are in range
How often should stroke risk be reassessed?
- at least annually
- reassess when reach 65 years of age
- if they develop new comorbidities
- DO NOT stop anticoagulation just because AF no longer detectable
- explain risk of stroke is 5x higher in person with AF
- anticoagulation reduced risk of stroke by 2/3rds so for most people benefit of anticoagulation outweighs risk.
