Atrial Fibrillation
paroxysmal: recurrent episodes last longer than 30 seconds but less than seven days. ( classical in athletes following alcohol the previous day, having syncope or sudden tiredness)
persistent: episodes lasting longer than seven days
Permanent: fails to terminate using cardioversion
The source of AF is often from myocardial tissue at the entrance to the four pulmonary veins.
Thromboembolism and stroke are the main complications → anticoagulate based on CHA₂DS₂-VASc
Rhythm control should be considered if rate control is ineffective.
Management
If UNSTABLE (Duration doesn’t matter)
Synchronised DC cardioversion (without waiting for anticoagulant cover):
AF: start 120–200 J
AFL: often converts at lower energy (50–100 J)
If STABLE (Go by duration) → choose Rate vs Rhythm.
AF / AFL <48 HOURS (or clearly known onset) -> Rhythm control is ALLOWED (either DC or Pharmacological). However, give periprocedural anticoagulation (heparin/LMWH)-No need to wait 3 weeks
DC cardioversion
AF: 120–200 J biphasic
AFL: 50–100 J often enough
Chemical cardioversion
AF: amiodarone, flecainide (if no structural heart disease, it is preferred)
AFL: ibutilide (watch QT)
After cardioversion, apply CHA₂DS₂-VASc to decide long-term anticoagulation
AF / AFL > 48 HOURS or UNKNOWN DURATION (a dilated atrium fits chronic AF)
Never cardiovert >48 h AF/AFL without anticoagulation (for 3 weeks) or TEE
Management is rate control + delayed cardioversion
Rate control
β-blocker or diltiazem
Anticoagulate for ≥3 weeks
DOAC or warfarin (INR 2–3)
Then cardiovert
Continue OAC ≥4 weeks after cardioversion
Then apply CHA₂DS₂-VASc to determine lifelong anticoagulation (NOT the timing of cardioversion)
Atrial flutter
Regular tachycardia at 150 bpm → think AFL 2:1 block until proven otherwise
AF + sepsis = rate control first, rhythm later
AF = chaos, AFL = organized loop.
Rules are IDENTICAL to AF
Management summary:
UNSTABLE → Shock
Stable
<48 h → Cardiovert along with periprocedural LMW heparin → no need to anticoagulate everyone for 4 weeks. Instead, apply CHA₂DS₂-VASc → lifelong OAC if indicated
>48 h / unknown -> Rate control + OAC 3 weeks → cardiovert, continue OAC ≥4 weeks or lifelong based on CHA₂DS₂-VASc score
Time decides cardioversion. CHA₂DS₂-VASc decides lifelong anticoagulation. INR Standard target is 2-3
Cardioversion is safe only if INR 2–3 for ≥3 weeks
Missed INR control = not anticoagulated
Mechanical valve → DOACs contraindicated
Persistent symptoms despite optimal medical therapy → think ablation.
Among valvular diseases, MS and Prosthetic valves possess a high risk for thromboembolism - choice is warfarin
Pill in pocket antiarrhythmic drug (PIP AAD) for paroxysmal AF => Early administration of flecainide has more efficacy than amiodarone
Anticoagulants:
Warfarin: Vit K antagonist (factors 2,7, IX, X). Fully reversible with vit K, needs frequent INR check
Apixaban (DOAC): Factor X inhibitor. No need of INR monitoring. Lowest risk of bleeding, or renal impairment
Dabigatran (DOAC): IIa inhibitor, antidote available; idarucizumab. Risk of GI bleed
“Mechanical valve → warfarin only.”
“AF default DOAC → apixaban.”
“Dabigatran = thrombin blocker + GI bleed.”
“DOACs do NOT need INR
Pitfalls:
“It’s flutter, stroke risk is low” → WRONG
Using CHA₂DS₂-VASc to decide acute cardioversion → WRONG
Chemical cardioversion after 48 h without anticoagulation → WRONG
Ignoring post-cardioversion anticoagulation → WRONG
Questions:
A 58-year-old with palpitations for 18 hours. ECG shows AF with a ventricular rate 140/min. BP 120/70, no heart failure, no chest pain. Best management?
Answer: AF <48 hours, stable → immediate cardioversion allowed.
2. Continue anticoagulant for four weeks after cardioversion in AF > 48 hours
3. AF < 48 hours, without structural heart disease -> Flecainide is preferred over Amiodarone for cardioversion. (reason: Flecainide converts AF fast (within 2 hours), Amiodarone is slow → Conversion may take 6–24 hours). Amiodarone reserved for patients with LVH or any structural abnormality
4. Flecainide is sodium channel blocker
5. This question: Separate physiological instability from symptom burden, Avoid reflex cardioversion thinking, & Respect rate-first strategy in chronic AF
A 72 year old referred by GP with chronically ↑ breathing difficulty and ↓ exercise intolerence for 3-4 weeks, had h/o IHD, have been in AF, and GP commenced warfarin, he is not in cardiac failure, BP and pulse relatively stable. most appropriate intervention?
A. Amiodarone, B.Flecainide, C. Bisoprolol, D. Digoxin, E. Verapamil
Answer: Bisoprolol (for rate control)
This patient is NOT unstable, and has chronic symptom
=> Chronic AF + IHD + elderly → RATE control first
Flecainide is contraindicated as patient has structural heart disease
6. Commonest site for radiofrequency ablation -> Pulmonary veins or adjacent to pulmonary ostia
7. 21-year-old, with WPW, BP 80/50, irregular pulse 170, bilateral basal crackle. Appropriate intervention? - DC conversion
8. 43-year-old athlete with syncope. history of isolated episode of palpitation at rest after alcohol consumption -> paroxysmal AF
AF is well recognised in individuals who are keen in distance athlets, and occurs related to excess alcohol. Suggest an extended Holter for 72 hours (investigation choice), and bisoprolol is the appropriate intervention.
9. AF on warfarin, for elective cardioversion -> the INR should be above 2 for preceeding 3-4 weeks.
The question was INR was 1.6 two weeks back, hence postponed elective cardioversion.
10. 75 year old, stable congestive cardiac failure with AF, which drug? Rivaroxaban
11. 55 year old man with paroxysmal AF, he would prefer a pill in pocket (PIP)? - Flecainide (early administration is effective than amiodarone. and this patient has no structural heart disease)
12. Why Flecainide (Class IC) is preferred over Amiodarone for cardioversion in <48 h AF (in patients without structural heart disease).
Answer: In <48 h AF, the aim is rapid restoration of sinus rhythm, not delayed chemical drift. Flecainide converts AF fast (within 1–3 hours). Amiodarone is slow (6–24 hours)
13. Valvular AF (prosthetic valve & Mitral stenosis. everythingelse is non-valvular including MR, AS, AR, TS etc) has very high thrombus risk, it has Different clot biology (left atrium + valve surface) and DOACs do not work reliably. always use warfarin, no need to apply CHADS2 score
14. A 70 year old man underwent DC cardioversion for AF, which factor predict long term maintanance of sinus rhythm. Answer was duration less than 6 months. (other options, alcohol, age, warf)
15. A 54 year old presents with irregular tachycardia (120/mt), he played cricket and previous day he consumed heavy alcohol. what is the most likely diagnosis? Answer; Paroxysmal AF.
Explanation: alcohol, caffeine, thyroid disorder, hypertension, wpw precipitates paroxysmal AF
16. AF for unknow periode patient, which drug may slow rate (adenosine, amio, digoxin, amlo, flecain). Answer; digoxin
Unknown duration = possible left atrial thrombus → cardioversion may cause stroke
digoxin controls rate without restoring sinus rhythm (slow AV node conduction), and does not terminate AF, therefore does not rise the risk of AF. Digoxin is especially helpful, when patient has heart failure and resting tachycardia
Digoxin is too slow to act, hence no role in acute settings
17. If asthma + AF; do not use β-blockers, look for a non-bronchospastic AV nodal blocker. In this question digoxin is preferred over dilzem, atenolol
18. After cardioversion (INR was between 2-3 for previous two weeks), how long should continue warf? Answer: 4 weeks
19. young male (50 years), after heavy drinking session, in the ED, with palpitation, no h/o previous cardiovascular disease, not in cardiac failure, ECG in AF, cardioversion choice? Answer: Flecainide
20. 18 year old in ED with syncope while playing, 24hour strip shows paoxysmal AF, QT interval 0.51 sec, rate control choice -> Metoprolol (choice; flecainide, amio, verapamil, adenosine). verapamil not chose because of lack of evidences, adenosine can provoke severe heart rate abnormalities in QT prolonged cases. Note: Bisoprolol is the usual choice for rate control
21. 55 year old, MR + AF + warfarin, INR 2, planned tooth extraction, what to do before procedure? Answer: maintain warf at therapeutic dose. (other choices: stop warf start UF heparin, stop warf start LMW heparin, stop warf for two days, stop warf start aspirin)
22. 80 years, HR 140, AF, BP stable, acute breathing difficulty and palpitation since 3 hours, next appropriate? Answer: DC Cardioversion
23. Primary mode of action of amio-> Answer; K channel antagonist (it delays depolarisation, ↑rease action potential, and inrease effective refractory period. Similar action drug-> Sotalol)
24. 62 year old, myasthenia gravis, with previous MI, left ventricular failure, and dilated atrium. Which drug to control AF? Answer: Digoxin (choices; Bisoprolol, Dilzem, Ivabradine, Verapamil).
Explanation: Dilated atrium implies chronic AF, left ventricular failure -> successful cardioversion is unlikely, therefore rate control with digoxin is more suitable. or combination therapy with dilzem and bisoprolol would be required. here dilzem - bcz of heart failure, bisoprolol-bcz of myesthenia are not preferred
25. 82 year old, acute breathing difficulty (3 hours) and palpitation, basal crackles on auscultation. HR 140, irregular. most appropriate for his AF? Answer DC cardioversion
Points:
Unstable = DC cardioversion irrespective of duration
TIME DECIDES CARDIOVERSION. AF < 48 hours, Stable → cardioversion allowed.
AF > 48 h / unknown, No immediate cardioversion. Rate control + OAC ≥3 weeks, Mandatory OAC ≥4 weeks after cardioversion
Do not use CHA₂DS₂-VASc to decide emergency cardioversion. It DECIDES ANTICOAGULATION
FLECAINIDE vs AMIODARONE
Flecainide (Class IC)
Na⁺ channel blocker
Rapid conversion (1–3 h)
Best for AF <48 h
Pill-in-the-pocket
Contraindicated in: Structural heart disease (LVH, heart failure)
Amiodarone
Slow conversion (6–24 h)
Reserved for: Structural heart disease
Fresh AF → fast drug (flecainide)
Scarred heart → safer drug (amiodarone)
CHRONIC AF (clues: Dilated LA) = RATE FIRST
ANTICOAGULATION RULES
INR target 2–3
If INR dips <2 → reset clock
Continue OAC ≥4 weeks post-CV
ABLATION Commonest site: Pulmonary vein ostia
AF TRIGGERS (IMT loves this)
Alcohol (“holiday heart”)
Endurance athletes
Thyroid disease
Hypertension
WPW
DRUG MECHANISMS (one-liners)
Flecainide → Na⁺ channel block
Amiodarone → K⁺ channel block → ↑ APD, ↑ ERP