AF & AFL

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

  • 1. DC cardioversion

AF: 120–200 J biphasic

AFL: 50–100 J often enough

• • 2. 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

• • 2. 1. Rate control

β-blocker or diltiazem

• • 2. 2. Anticoagulate for ≥3 weeks

DOAC or warfarin (INR 2–3)

• • 2. 3. Then cardiovert

       4. Continue OAC ≥4 weeks after cardioversion

       5. 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:

1. UNSTABLE → Shock

2. 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:

1. 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