Medical and surgical management of atrial fibrillation

1. Atrial Fibrillation
Dr. K. Srikanth
DNB (Cardiothoracic Surgery) Resident – 2nd year
NH, Bangalore
06/08/2018

2. Definition
Source – Braunwald’s Heart Disease, 10th edtition

3. Problems in AF
• Loss of atrial kick during cardiac cycle (30% of cardiac output
lost)
• Increased ventricular rate – so reduced diastolic filling/
tachycardia-induced cardiomyopathy (TIC)
• Risk of thrombus formation and subsequent embolisation

4. Epidemiology
• Most common arrhythmia in clinical practice
• 33% of arrhythmia-related hospitalisation
• Men > Women
• 5-fold increase in stroke risk
• 2-fold increase in all cause mortality

5. Classification of AF
• Paroxysmal AF : <7 days duration
• Persistent AF : 7 days – 1 year
• Long – standing AF : > 1 year
• Permanent AF : AF refractory to cardioversion

6. Lone AF
• AF in a person <60 yrs of age with no H/O Hypertension or structural
heart disease
• Clinical significance – Less risk of thrombo-embolism (no need for
anti-coagulation)
• Safe use of rhythm control drugs

7. Electrophysiology of AF
• Concept of rotors and drivers
• Most of the ‘drivers’ are located around the pulmonary veins (basis of
pulmonary vein isolation) in paroxysmal AF
• In persistent/ long-standing AF, changes such as interstitial fibrosis
happen in the atrial substrate (basis of RFA/ cryo-ablation)

8. Focal activation – multiple wavelet theory

9. Causes of AF - Cardiac
• Valvular heart disease (MS,MR most common)
• Ischemic heart disease
• HOCM
• DCM
• Restrictive cardiomyopathy
• Cardiac tumours
• Post-cardiac surgery

10. Non – Cardiac causes
• Hyperthyroidism (Most common reversible cause of AF)
• Electrolyte imbalance (Hypokalemia, Hypomagnesemia)
• Obstructive sleep apnea
• Obesity
• Drug induced (sympathomimetics)
• Binge alcohol (Holiday heart)
• Pulmonary embolism

11. Clinical features
• Asymptomatic (25%)
• Palpitation
• Giddiness
• Fatigue
• Dyspnoea
• Syncope (rare) – due to reduction in stroke volume
• Polyuria – due to release of ANP

12. Clinical signs
• Irregularly irregular pulse with variable volume
• Pulse deficit
• Irregular Jugular venous pulsation
• Variable intensity of S1 on auscultation

13. ECG findings
• Absence of P wave
• Presence of fibrillatory ‘f’ waves
• Irregular R-R interval
• Absence of isoelectric
baseline

14. Other ECG presentations of AF
No ‘f’ waves but irregular R-R interval

15. Fast AF mimicking Sinus tachy/ SVT

16. AF with CHB and junctional rhythm

17. Ashman’s phenomenon
RBBB morphology of short cycle QRS following a long cycle QRS, causes diagnostic
confusion with VPCs

18. Calculating ventricular rate in AF
• One big box – 0.2 seconds
• Calculate number of QRS complexes in 6 seconds (30 big boxes)
• Multiply by 10 = ventricular rate in AF

19. Fast and slow AF
Ventricular rate – 150 bpm
Ventricular rate > 100 bpm is Fast AF
Ventricular rate – 40 bpm
Ventricular rate < 60 bpm is Slow AF

20. Atrial Fibrillation vs Atrial Flutter

21. Atrial fibrillation mimicking Atrial Flutter

22. Diagnostic work-up
• 24 – hour Holter monitoring (24-48 hours)
• Mobile cardiac outpatient telemetry (upto 30 days)
• Thyroid function tests, LFT, RFT
• Echocardiography – TTE/ TEE

23. 24 hour Holter monitoring
• Records 24 hour ECG
continuously
• Patient records significant events
by pressing a button
• The 24 hr ECG is analysed the
next day for arrhythmias

24. Mobile cardiac outpatient telemetry
(MCT)

25. Role of echocardiogram in AF
• Primary pathology causing AF
• LA size (Normal <39mm)
• LV function
• Presence of LAA clot (TEE has better sensitivity)

26. LAA clot – TEE (2 chamber view)

27. Management of Acute AF
• Hemodynamically unstable patient – electrical or pharmacological
cardioversion
• Always look for LAA clot before cardioversion
• Electrical cardioversion – 150-200 J biphasic shock
• Pharmacological – Ibutilide / amiodarone/ procainamide

28. • Hemodynamically stable patient – Oral propafenone(300-600mg) or
flecainide (100-200mg)
• Oral Beta-blockers/ CCBs for rate control
• Electrical / pharmacological cardioversion debatable
• Anticoagulation for atleast 4 weeks after cardioversion

29. Management of Chronic AF

30. Goals of management
• Anti-coagulation
• Rate control
• Rhythm control
• Correcting the underlying cause of AF

31. Anti-Coagulation

32. Risk stratification for stroke

33. HAS-BLED score to stratify bleeding risk

34. Anticoagulation guidelines

35. • Target INR : 2-3
• Anti-coagulation to be started for all cases of AF except lone AF/ in
the presence of contra-indications for anti-coagulation
• Options for anti-coagulation
Warfarin/ Coumarin
NOACs
LMWH

36. Rate control
• First line – Oral beta-blockers/ CCBs verapamil or diltiazem
• Digoxin – currently used only for AF with heart failure
• Target a resting heart rate of <110/min

37. Rhythm control
• Best drug – Amiodarone
• Risk of drug toxicity
• Alternatives – Sotalol, flecainide, propafenone, dronaderone
(preferred for lone AF patients)

38. Non-pharmacological treatment
• Atrial pacing can prevent AF compared to ventricular pacing
• Catheter-based Radio-frequency ablation
• Cryo-balloon ablation
• Magnetic remote navigation
• AV node ablation – causes permanent CHB and ventricular pacing is done

39. Radio-frequency ablation

40. Cryo-balloon ablation

41. Watchman device for preventing embolism

42. Surgical management of AF
• Cut and sew Maze procedure
• Consists of 12 incisions across LA
and RA, LAA and RAA plicated & excluded
• Disrupts the aberrant electrical
Pathways
Newer – Cryo-maze, RFA, laser maze,
High-intensity ultrasound

43. Pulmonary vein isolation
• Pulmonary vein cuff is
isolated surgically/ RFA/ cryo
• Useful for paroxysmal AF, not
for persistent AF
• RFA PVI can be done
thoracoscopically

44. Epicardial appendage exclusion procedures

45. Corridor procedure

46. Post-operative AF
• Incidence – 25-40% after CABG/ valve surgery
• Peak incidence on POD 2
• Multifactorial - adrenergic activation, inflammation, atrial ischemia,
electrolyte disturbances(hypokalemia/ hypomagnesemia) and genetic
factors
• Two-fold risk of post-op stroke

47. Management
• Pre-op prophylactic amiodarone can prevent post-op AF
• Mainstay drugs – Beta-blockers, amiodarone, sotalol, ibutilide
• Magnesium/ potassium correction
• Atorvastatin, hydrocortisone and PUFA/omega-3 FA reduce risk of
post-op AF due to anti-inflammatory action

48. Management of post-operative AF (guidelines)