Atrial Fibrilation Flashcards
What is AF? (1)
Irregular, disorganised electrical activity in the atria.
What are the main feature of AF? (3)
Supraventricular tachyarrhythmia
Rapid firing impulses -> disorganised atrial depolarisation and ineffective atrial contractions.
AV nodes receive more electrical impulses that it can conduct. -> Irregular ventricular rhythm.
What is the ventricular rate of untreated AF? (1)
160-180bpm (slower in elderly)
What is the effect of irregular atrial contractions? (1)
Blood status clot formation
What is paroxysmal AF? (3)
Episode lasting > 30 seconds but < 7 days.
Often < 48 hrs
Self-limiting and recurrent.
What is persistent AF? (3)
Episodes lasting > 7 days
Or < 7 days but needs cardioversion.
Spontaneous termination of arrhythmias = unlikely to occur.
What is permanent AF? (3)
Fails to terminate using cardioversion.
Terminated but relapses within 24 hrs.
A.K.A. Long-standing AF (>1yr) where cardioversion hasn’t been indicated or attempted.
What are the common causes of AF? (5)
Hypertension
IHD
MI
VHD
Hyperthyroidism
What are the cardiac/valvular causes of AF? (7)
CHF
RVD
A/VH
CHD
Wolf-Parkinson-White syndrome
Sick-sinus syndrome
Inflammatory disease (pericarditis, amyloidosis, myocarditis)
What are the non-cardiac causes of AF? (5)
Acute infection
Thyrotoxicosis
Diabetes
Electrolyte Depletion (low K/Na)
Medication: Thyroxine, Bronchodilators
What lifestyle factors can cause AF? (4)
Excessive caffeine
Alcohol abuse
Obesity
Smoking
What are the complications of AF? (5)
Stroke + thromboembolism
HF
Tachycardia-induced cardiomyopathy and critical cardiac ischaemia.
Reduced QofL
Higher risk of mortality.
What are the main symptoms of AF? (5)
Breathlessness
Palpitations
Chest Discomfort
Syncope/Dizziness
Stroke/TIA
What additional symptoms can be present for AF? (4)
Reduced exercise tolerance.
Malaise
Decreased in mentation
Polyuria
Explain the diagnostic process of AF. (7)
Manual pulse palpation (irregular pulse)
12-lead ECG
If paroxysmal AF suspected: 24-hr ambulatory ECG.
Initial tests: FBC, Clotting profile, U+E, TFTs
Cardiac troponin, BNP, WCC, ESR, LFT.
CXR
Transthoracic Echocardiography (ESC - all patients. NICE - LT management, cardioversion considered, high risk of structural/functional cardiac disease)
What is the main difference between AF + normal ECG? (1)
AF = no P waves v Normal = P waves before PR interval.
What are the differential diagnoses of AF? (6)
Atrial flutter
Atrial extrasytoles
Ventricular ectopic beats
Sinus tachycardia
Supraventricular tachycardia (atrial tachycardia, AVNRT tachycardia + WPW)
Multi focal atrial tachycardia
Define atrial flutter. (1)
Saw-tooth pattern of atrial activation on ECG.
Define atrial extrasystoles. (1)
Common
Cause irregular pulse.
Define sinus tachycardia. (1)
SR > 100bpm
State the steps of managing AF. (5)
Admit:
- Haemodynamically unstable, rapid pulse (>150bpm) low BP (< 90mmHg)
- Loss of consciousness, severe dizziness/syncope, ongoing chest pain, increasing breathlessness.
Underlying causes:
- Cardiac causes (HPT, VHD, HF, IHD)
- Respiratory (Chest infections, PE + lung cancer)
- Systemic (Excessive alcohol intake, thyrotoxicosis, electrolyte depletion, infections and diabetes)
Treat the arrhythmias:
- Rate control (Beta-blocker or rate limiting CCB)
- Rhythm control (pharmacological or electrical cardioversion)
Assess stroke risk:
- CHA2Ds2VASc
Risks vs. Benefits:
- ORBIT
Follow up:
- Rate control tx
- Anticoagulants
Explain rate control treatment of AF when haemodynamically stable. (4)
First line > 48 hrs unless suitable for rhythm control/investigations for rhythm ongoing.
Beta-blocker (NOT sotalol)
Or rate limiting CCB (Diltiazem/Verapamil)
Digoxin monotherapy (very little exercise or other options ruled out.)
Explain rhythm control treatment of AF when haemodynamically stable. (7)
Cardioversion:
- Pharmaceutical +/- rhythm control for people with AF whose symptoms continue after HR has been controlled or for whom a rate control strategy hasn’t been successful.
- New onset AF (< 48 hrs)
- Revserible cause (e.g. chest infection)
- HF caused/worsened by AF
- Atrial flutter suitable for ablation
- Clinical judgement of px.
- May take time to determine if suitable for rhythm - in interim give rate.
Explain the management of acute AF when haemodynamically unstable. (4)
Pharmacological/electrical cardioversion for new-onsent AF who’s going to be treated by rhythm control
Pharmacological cardioversion offer:
- Flecanide or Amiodarone (no structural or IHD) OR Amiodarone (structural HD)
- > 48 hrs (or uncertain) and LT rhythm control, delay cardioversion until maintained on therapeutic anticoagulation for min. 3.weeks. During this period offer rate control as appropriate.
Anticoagulation
Bleed risk (ORBIT)
What condition should you avoid the use of Beta-blockers? (1)
Hx of obstructive airway disease (COPD/Asthma)
Give e.g. of B-blockers used for AF rate control. (4)
Atenolol,Acebutolol, Metoprolol, Nadolol, Oxprenolol, Propanolol.
Lone AF - Atenolol (50-100mg daily, monitor HR and BP to titrated against response.)
AF with Hx MI - Metoprolol, Propranolol, Atenolol
Af with Hx HF - Bisoprolol, Carvedilol or Nebivolol.
What are the common s/e of beta blockers? (10)
Bradycardia/Hypotension
Cold Extremities
Disturbed sleep and nightmares (less likely with water soluble agents e.g. Atenolol)
Sexual dysfunction
Hypoglycaemia or Hyperglycaemia in patients +- diabetes
Mask signs of hypoglycaemia
Withdrawal effects
Fatigue
Explain the use of CCB in AF’s rate control. (4)
Rate-limiting (Diltiazem (off-label) + Verapamil)
Simvastatin capped at 20mg
Avoid in AF (not amlodipine) = further depresses cardiac function and exacerbate symptoms.
S/e: Headache, dizziness, hypotension, bradycardia.
What are the main features of Pill in the pocket? (3)
Flecainide
Infrequent paroxysms and few symptoms indicted by known precipitants (alcohol, caffeine)
Paroxysmal AF consider if:
- No Hx of LV dysfunction/valvular/IHD and
- Have Hx of infrequent symptomatic episodes and
- Have SBP > 100 mmHg and resting HR > 70 bpm and
- Able to understand how to take and use medicine.
