A comprehensive approach to Atrial Fibrillation. Everything you need to know about Atrial fibrillation. Including recent 2014 AHA guidelines of management.
4. Atrial fibrillation
Atrial fibrillation(AF or A fib), is a
supraventricular arrhythmia characterised
electrocardiographically by low-amplitude
baseline oscillations(fibrillatory or ‘f’ waves)
and an irregularly irregular ventricular rhythm.
The ‘f’ waves have a rate of 300-600 bpm
and are variable in amplitude, shape and
timing.
The ventricular rate during Afib typically is
100-160 bpm
5. Definition
Atrial fibrillation(AF or A fib), is a
supraventricular arrhythmia characterised
electrocardiographically by low-amplitude
baseline oscillations(fibrillatory or ‘f’ waves)
and an irregularly irregular ventricular rhythm.
Atrial fibrillation Vs Atrial flutter??
Irregularly irregular R-R intervals
Absent ‘p’ waves
Fibrillatory or ‘f’ waves
Atrial fibrillation
6. Incidence
Most common sustained cardiac arrhythmia
Incidence and prevalence increases with
age
The incidence
<0.5% below 50Yrs
2% in age 60-69
4.6% in age 70-79
8.8% in age 80-89
Men > Women
Whites > Blacks
7. Pathophysiology
1. Atrial structural abnormalities
Disturbance of normal atrial architecture
Atrial ischemia
Extra cardiac factors
Autonomic system
2.Electrophysiological mechanisms
Multiple wavelet theory
Automatic focus theory
3. Other pathophysiological mechanisms
11. Causes & risk factor a/w Afib
Hypertension with LVH, IHD, MVD,
Cardiomyopathies, Constrictive pericarditis,
Cardiac tumours, Pulmonary hypertension
and Diabetes.
Obesity and Obstructive sleep apnea.
Temporary causes: Alcohol, Open heart or
thoracic surgery, Myocardial infarction,
Pericarditis, Myocarditis and Pulmonary
embolism.
Reversible causes: Hyperthyroidism
12. Terminology Features
1. Paroxysmal AF Spontaneous termination <7 days
2. Persistent AF Not self-terminating lasting >7 days
3. Long standing AF Persistent AF for >1 year
4. Permanent AF Long standing AF refractory to
cardioversion
5. Lone AF Occurs in age group <60 years with
no H/o HTN/Heart disease
6. Nonvalvular AF Absence of rheumatic mitral
stenosis, a mechanical or
bioprosthetic heart valve, or mitral
valve repair
Classification
15. Clinical features
Hallmark of AF on physical examination:
Irregularly irregular pulse.
Short R-R intervals lead to low LV diastolic filling,
low stroke volume and absence of peripheral
pulses which results in “pulse deficit.”
Other findings: Irregular jugular venous pulsations
and variable intensity of first heart sound.
19. Stroke with A Fib
Blood stasis
Abnormal
blood
constituents
Left atrium
thrombus
To carotid artery
Anatomical
and structural
defects
20. Diagnostic evaluation
Clinical history and Physical examination
ECG
Holter monitoring
Stress test
ECHO
Chest radiograph
Blood tests
21. ECG
‘p’ waves are absent and R-R interval is variable.
Absent ‘p’ waves are replaced by small irregular oscillations,
called ‘f’ waves(f waves 350-600 beats /min).
ventricular response is grossly irregular at 100-160 beats /min.
Rate : No. of R waves x 10 ( 6 sec strip)
27. Approach to A Fib
Type of Afib
Complete history
Symptoms
?Structural heart disease
Exclude CAD
Identify correctable Secondary/Reversible
causes
Develop a treatment strategy
28. Strategies for treating Atrialfibrillation
Rhythm control (including cardioversion)
OR
Rate control
PLUS
Thromboembolic risk prevention:
based on CHA2DS2-VAS2C score
29. Acute management
For hemodynamically unstable patients:
Sedate if possible and perform an immediate cardioversion.
If refractory to cardioversion, use IV amiodarone, ibutilide, or
procainamide.
For hemodynamically stable patients:
Initiate anticoagulation and rate control.
If first occurrence, consider cardioversion after adequate
anticoagulation (4 weeks) or no clot seen on TEE and therapeutic
anticoagulation initiated.
With recurrence, consider referral to an electrophysiologist.
Consider admission if history suggests a precipitating event (e.g.,
acute MI, PE, HF, etc.).
Rule out secondary causes based on history.
Perform complete evaluation.
30. Rhythm and rate control approaches
Rhythm control
Cardioversion (electrical or pharmacological)
Pharmacological agents (Class IC and III
antiarrhythmics)
Surgery (maze procedure, ablation)
Device implantation (pacemaker)
Rate control
Pharmacological agents (AV node blockers)
Surgery with device implantation (ablation plus
pacemaker insertion)
31. Rate control medications
-Metoprolol / Esmolol: IV or Oral
-Diltiazem: IV or Oral
-Verapamil: Oral Only
-Digoxin: Patients with hypotension
-Amiodarone: Also for rhythm control
32. Rhythm control
Synchronized DC cardioversion
-Emergencies/Hemodynamic instability
-Greater efficacy than medications
Pharmacologic cardioversion
-If AF < 7days –dofetilide, flecainide, ibutilide,
propaferone or amiodarone
-If AF > 7 day –dofetilide or amiodarone
33. Rhythm control
Synchronized DC cardioversion
-Emergencies/Hemodynamic instability
-Greater efficacy than medications
Pharmacologic cardioversion
-If AF < 7days –dofetilide, flecainide, ibutilide,
propaferone or amiodarone
-If AF > 7 day –dofetilide or amiodarone
34. Rate control as preferred therapy
Age > 65, less symptomatic,
hypertension
Recurrent afib
Previous antiarrhythmic drug failure
Unlikely to maintain sinus rhythm
(enlarged LA)
36. Rhythm control as preferred therapy
? First episode afib
Reversible cause (alcohol)
Symptomatic patient despite rate control
Patient unable to take anticoagulant (falls,
bleeding, noncompliance)
CHF precipitated or worsened by afib
? Young afib patient (to avoid chronic
electrical and anatomic remodeling that
occurs with afib)
41. Thrombo-embolic Risk and Treatment
Risk Based Antithrombotic Therapy
CHA2DS2-VASc score recommended to
assess stroke risk (Class I)
42. How do we determine stroke risk ?
0 points – low risk (1.2-3.0 strokes per 100
patient years)
1-2 points – moderate risk (2.8-4.0 strokes
per 100 patient years)
> 3 points – high risk (5.9-18.2 strokes per
100 patient years)
43. Thrombo-embolic Risk and Treatment
Risk Based Antithrombotic Therapy
Contd…
With prior stroke, TIA, or CHA2DS2-VASc
score ≥2, oral anticoagulants recommended.
Options include:
Warfarin
Dabigatran, rivaroxaban, or apixaban (Class I)
With nonvalvular AF and CHA2DS2-VASc
score of 0, it is reasonable to omit
antithrombotic therapy (Class IIa)
44. Thrombo-embolic Risk and Treatment
Risk Based Antithrombotic Therapy
With CHA2DS2-VASc score ≥2 and end-stage
CKD (CrCl <15 mL/min) or on hemodialysis, it
is reasonable to prescribe warfarin for oral
anticoagulation (Class IIa)
With nonvalvular AF and a CHA2DS2-VASc
score of 1, no antithrombotic therapy or
treatment with oral anticoagulant or aspirin
may be considered (Class IIb)
After coronary revascularization in patients
with CHA2DS2-VASc score ≥2, it may be
reasonable to use clopidogrel concurrently
with oral anticoagulants but without aspirin
(Class IIb)
46. Bleeding Risk Accessment
• Assessment of bleeding risk should be
part of the clinical assessment of AF
patients prior to starting anticoagulation
• Antithrombotic benefits and potential
bleeding risks of long-term coagulation
should be explained and discussed with
the patient
• Aim for a target INR of between 2.0 and
3.0
• HAS-BLED Score
47. Bleeding Risk Accessment(HAS-BLED Score)
Points
Hypertension (> 160 mm Hg systolic) 1
Abnormal renal or hepatic function 1-2
Stroke 1
Bleeding history or anemia 1
Labile INR (TTR < 60%) 1
Elderly (age > 75 years) 1
Drugs (antiplatelet, NSAID) or alcohol 1-2
High risk (> 4%/year)>4
Moderate risk(2-4%/year)2-3
Low risk(< 2%.year)0-1
49. Novel oral anticoagulants
Dabigatran
Oral direct thrombin inhibitor
Twice daily dosing
Renal clearance
Rivaroxaban
Direct factor Xainhibitor
Once daily (maintenance), twice daily (loading)
Renal clearance
Apixaban
Direct factor Xainhibitor
Twice daily dosing
Hepatic clearance
Edoxaban
Direct factor Xainhibitor
Once daily dosing
Hepatic clearance
50. Prevention of Thromboembolism
With AF or atrial flutter for ≥48 h, or unknown duration,
anticoagulate with warfarin for at least 3 wk before and 4
wk after cardioversion (Class I)
With AF or atrial flutter for >48 h or unknown duration,
requiring immediate cardioversion, anticoagulate as soon
as possible and continue for at least 4 wk (Class I)
With AF or atrial flutter <48 h and high stroke risk, IV
heparin or LMWH, or factor Xa or direct thrombin inhibitor,
is recommended before or immediately after
cardioversion, followed by long-term anticoagulation
(Class I)
With AF or atrial flutter <48 h and low thromboembolic
risk, IV heparin, LMWH, a new oral anticoagulant, or no
antithrombotic may be considered for cardioversion
(Class IIb)
51. Rate Control guidelines(AHA)
Control ventricular rate using a beta blocker or non-
DHP CCBs for paroxysmal, persistent, or permanent
AF (Class I)
IV beta blocker or non-DHP CCBs is recommended
to slow ventricular heart rate in the acute setting in
patients without pre-excitation. In hemodynamically
unstable patients, electrical cardioversion is
indicated (Class I)
A heart rate control (resting heart rate <80 bpm)
strategy is reasonable for symptomatic management
of AF (Class IIa)
IV amiodarone can be useful for rate control in
critically ill patients without pre-excitation (Class IIb)
52. Rate Control guidelines(AHA)
AV nodal ablation with permanent ventricular pacing
is reasonable when pharmacological therapy is
inadequate and rhythm control is not achievable
(Class IIa)
A lenient rate-control strategy (resting heart rate
<110 bpm) may be reasonable when patients
remain asymptomatic and LV systolic function is
preserved (Class IIb)
Non-DHP CCBs should not be used in
decompensated HF (Class III)
With pre-excitation and AF, digoxin, Non-DHP
CCBs , or amiodarone should not be administered
(Class III)
53. Restoration of Sinus Rhythm
guidelines(AHA)
Principles of Cardioversion:
CV may be achieved by means of a drug or an electrical shock.
Direct-current CV is more effective than pharmacological CV.
The more recent the onset of AF, the more effective is
pharmacological CV.
The primary disadvantage of electrical CV is that it requires
sedation or anesthesia.
The primary disadvantage of pharmacological CV is the risk of
ventricular proarrhythmia.
The risk of thromboembolism or stroke does not differ between
pharmacological and electrical CV.
Significant sinus bradycardia after CV can occur in patients on high-
dose AV nodal blocking drugs.
Antiarrhythmic drug therapy may be administrated prior to CV to
facilitate long-term success and maintenance of normal sinus
rhythm.
54. Restoration of Sinus Rhythm
guidelines(AHA)
Direct Current Cardioversion:
Shocks should be delivered synchronous to the R-wave.
The use of a biphasic defibrillator should be considered with
150-200 joules as the initial energy setting.
When a rapid ventricular response does not respond
promptly to pharmacological measures for AF patients with
ongoing myocardial ischemia, symptomatic hypotension,
angina, or HF, immediate CV is recommended.
In case of early relapse of AF after CV, repeated direct-
current CV attempts may be made following administration of
antiarrhythmic medication.
Electrical CV is contraindicated in patients with digitalis
toxicity or hypokalemia.
55. Restoration of Sinus Rhythm
guidelines(AHA)
Pharmacological Cardioversion:
IV ibutilide is an effective drug available to convert AF.
Due to its risk of torsades de pointes, ibutilide should be
avoided in patients with severe systolic dysfunction or a
prolonged QTc (>480 ms).
More effective for conversion of atrial flutter than of AF;
more effective in cases of more recent onset.
Can also be used to facilitate electrical CV when it is
unsuccessful, or when there is an immediate recurrence
of AF after initially successful CV.
Consider IV magnesium (2 grams) prior to giving
ibutilide to reduce risk of torsades de pointes.
ECG monitoring must be performed for 4 hours after
administration.
56. Restoration of Sinus Rhythm
guidelines(AHA)
Pharmacological Cardioversion:
Flecainide and Propafenone
Both flecainide and propafenone have been studied for
their use as a “pill-in-the pocket” approach to
cardioverting AF.
Generally, a beta blocker or a calcium channel blocker
should be taken an hour prior to taking the
antiarrhythmic drug when trying to convert AF to SR. For
a person >70 Kg, 300 mg of flecainide or 600 mg of
propafenone should be administered. For <70 Kg, the
dose for flecainide and propafenone is 200 mg and 450
mg, respectively. After administration of the drug, heart
rhythm must be monitored for at least 4-8 hours.
57. Maintenance of Sinus Rhythm
guidelines(AHA)
Principles of Antiarrhythmic Drug Therapy(AAD):
Pharmacological therapy to maintain SR is indicated in
patients who have troublesome symptoms related to
paroxysmal AF or recurrent AF after CV who can
tolerate antiarrhythmic drugs (AADs) and have a good
chance of remaining in SR.
AAD choice is based on side effect profiles and the
presence or absence of structural heart disease, HF,
and hypertension (see flow diagram).
Drug choice should be individualized and must account
for underlying renal and hepatic function.
Goals of drug therapy are to decrease the frequency
and duration of episodes, and to improve symptoms.
58. Maintenance of Sinus Rhythm
guidelines(AHA)
Principles of Antiarrhythmic Drug Therapy:
AF recurrence while taking an AAD is not indicative of
treatment failure and does not necessitate a change in
antiarrhythmic therapy.
An AAD should be abandoned when it does not result in
symptomatic improvement or causes adverse effects.
Ensure normal electrolyte status and appropriate
anticoagulation prior to starting AAD therapy.
Initiate AV nodal blockade prior to use of an AAD (e.g.
flecainide) that does not provide substantial AV node
blockade.
Initiate therapy at low dose and titrate up as needed and
after evaluating drug effects on ECG parameters.
59. AF complicating ACS
Urgent cardioversion of new-onset AF in the setting of ACS is
recommended for patients with hemodynamic compromise,
ongoing ischemia, or inadequate rate control (Class I)
IV beta blockers are recommended to slow RVR with ACS and no
HF, hemodynamic instability, or bronchospasm (Class I)
With ACS and AF with CHA2DS2-VASc score ≥2, anticoagulation
with warfarin is recommended unless contraindicated (Class I)
Amiodarone or digoxin may be considered to slow RVR with ACS
and AF and severe LV dysfunction and HF or hemodynamic
instability (Class IIb)
Non-DHP CCBs might be considered to slow RVR with ACS and
AF only in the absence of significant HF or hemodynamic
instability (Class IIb)
60. Hyperthyroidism
Beta blockers are recommended to
control ventricular rate with AF
complicating thyrotoxicosis unless
contraindicated (Class I)
When beta blockers cannot be used, a
Non-DHP CCBs is recommended to
control ventricular rate (Class I)
61. Pulmonary diseases
Non-DHP CCBs is recommended to
control ventricular rate with AF and
COPD (Class I)
Cardioversion should be attempted for
patients with pulmonary disease who
become hemodynamically unstable with
new-onset AF (Class I)
62. WPW and pre-excitation syndromes
Cardioversion is recommended for patients with
AF, WPW syndrome who are hemodynamically
compromised (Class I)
IV procainamide or ibutilide to restore sinus
rhythm or slow ventricular rate is (Class I)
recommended for patients with pre-excited AF
who are not hemodynamically compromised
(Class I)
IV amiodarone, adenosine, digoxin, or non-DHP
CCBs in patients with WPW syndrome who
have pre-excited AF is potentially harmful
(Class III)
63. AF during pregnancy
Digoxin, a beta blocker, or a nondihydropyridine
calcium channel antagonists are recommended
for rate control.
Direct cardioversion if there is hemodynamic
instability
Except in patients with low risk profile, either
aspirin or an anticoagulant is recommended for
prevention of thromboembolic complications.
Unfractionated or LMWH in 1st & last trimester,
oral anticoagulant in 2nd trimester for high risk
group.
Quinidine or procainamide for pharmacologic
cardioversion in stable patients.
64. Heart failure
A beta blocker or non-DHP CCB is
recommended for persistent or permanent AF in
patients with HFpEF (Class I)
In the absence of preexcitation, an IV beta
blocker (or a non-DHP CCB with HFpEF) is
recommended to slow ventricular response to
AF in the acute setting, with caution in patients
with overt congestion, hypotension, or HFrEF
(Class I)
In the absence of pre-excitation, IV digoxin or
amiodarone is recommended to control heart
rate acutely (Class I)
Digoxin is effective to control resting heart rate
with HFrEF (Class I)
65. Heart failure
IV amiodarone can be useful to control heart rate with
AF when other measures are unsuccessful or
contraindicated (Class IIa)
In patients with chronic HF who remain symptomatic
from AF despite a rate-control strategy, it is reasonable
to use a rhythm-control strategy (Class IIa)
Amiodarone may be considered when resting and
exercise heart rate cannot be controlled with a beta
blocker (or a non-DHP CCB with HFpEF) or digoxin,
alone or in combination (Class IIb)
For rate control, IV non-DHP CCB, IV beta blockers, and
dronedarone should not be given with decompensated
HF (Class III)
66. How Can Atrial Fibrillation Be
Prevented?
Following a healthy lifestyle and taking steps
to lower your risk for heart disease may help
you prevent atrial fibrillation (AF). These
steps include:
Following a heart healthy diet that's low in
saturated fat, trans fat, and cholesterol. A
healthy diet includes a variety of whole
grains, fruits, and vegetables daily.
Not smoking.
Being physically active.
Maintaining a healthy weight.
67. If already having heart disease or other AF
risk factors, regular checkup and followup. In
addition to adopting the healthy habits
above:
Advise DASH eating plan to help lower blood
pressure.
Keep cholesterol and triglycerides at healthy
levels with dietary changes and medicines (if
prescribed).
Limit or avoid alcohol.
Control of blood sugar level if diabetic.
Medical care and medicines as prescribed.
68. Summary
Most common cardiac arrhythmia
High prevalence
Stroke and Heart failure – Risk
Treatable disease with early and proper
interventions.