Atrial Fibrillation – CCS2014

  • Paroxysmal: self-terminating <7d
  • Persistent: sustained >7d or req cardioverison
  • Permanent: >1yr
  • Valvular: rheumatic MV dz, prosthetic valve, valve repair
  • Lone AF: age
SAF score – impact on QOL:
  • 0 – asymptomatic, 1 – min effect, 2 – minor, 3 – moderate, 4 – severe
High risk pt (stroke): No therapeutic OAC >3 weeks plus one of the following:
  • Unknown onset or onset >48hr
  • mechanical valve,  INR<2.5
  • Rheumatic valve dz
  • recent (<6mo)  stroke / TIA
Symptoms:
  • Asymptomatic
  • Stroke
  • Palpitation, reduced exercise capacity
  • Syncope, chest pain
  • Heart failure, dyspnea

1 In a patient who presents with new onset atrial fibrillation, look for an underlying cause (e.g., ischemic heart disease, acute myocardial infarction, congestive heart failure, cardiomyopathy, pulmonary embolus, hyperthyroidism, alcohol, etc.)

Acute causes:
  1. Cardiac: CHFcardiomyopathy ( hypertrophic, dilated, restrictive), myo/pericarditis, ischemia/MI, hypertensive crisis, cardiac surgery
  2. Pulmonary: acute pulmonary disease or hypoxia – COPD flare, pneumonia; PE
  3. Metabolic: high catecholamine states – stress, infection, postop, pheochromocytoma, thyrotoxicosis
  4. Drugs: alcohol (holiday heart), cocaine, amphetamines, theophylline, (no association with caffeine?)
  5. Neurogenic: subarachnoid hemorrhage, ischemic stroke
Chronic causes:
  1. increased age, obesity, OSA, vagally-mediated (habitual aerobic training)
  2. HTN, ischemia, valve dz (MV, TV, AoV)
  3. CMP, hyperthyroidism
Evaluation:
  1. Hx + PEx:
    • Establish etiology: alcohol, caffeine, drugs, chest pain, SOB, CHF symptoms, infection
    • Identify reversible causes: hyperthyroidism, ventricular pacing, SVT, exercise etc
    • Identify risk factors: HTN, OSA, LV dysfunction
    • Determine thromboembolic & bleeding risks
    • BP & HR
  2. ECG –
    1. establish dx, assess for structural heart dz (MI, LVH, Atrial enlargement, congenital heart dz)
    2. electric heart dz (ventricular pre-excitation, Brugada syndrome)
    3. Identify risk factors for complication of Tx of AF – conductance disturbances, sinus node dysfunction / abn repolarization
    4. document PR, QT, QRS intervals
  3. B/W: CBC, extended lytes (Ca, Mg, K etc), TSH, Cr/BUN, LFT
  4. fractionated metanephrines and catecholamines in a 24-hour urine collection
  5. CXR – exclude lung dz, CHF, baseline in pt receiving amiodarone
  6. Echo – LA size, valvular functions, pericardium, LV size & function, exclude congenital heart dz (ASD)
  7. FOBT before anticoagulation
  8. r/o ischemia – AF unlikely in absence of other sx of ischemia

2 In a patient presenting with atrial fibrillation,
a) Look for hemodynamic instability,
b) Intervene rapidly and appropriately to stabilize the patient.

Unstable if AF causing

  • hypotension
  • pulmonary edema, dyspnea, heart failure
  • altered mental status, syncope, neurological symptoms
  • chest pain /MI

Urgent Rate control and cardioversion if rate control not effective:

  • IV diltiazem, metoprolol, verapamil, digoxin
  • Pads in either an anterior-lateral (AL) or anterior-posterior (AP) position followed by synchronized cardioversion at 100-200 J biphasic.  Current literature shows no significant difference in pad placement
  • If cardioversion fails, try amiodarone load or diltiazem.

3 In an individual presenting with chronic or paroxysmal atrial fibrillation,
a) Explore the need for anticoagulation based on the risk of stroke with the patient,
b) Periodically reassess the need for anticoagulation.

Predictive index for stroke:
CHADS2
  • CHF 1 , HTN 1, ≥75yo 1, DM 1, Stroke / TIA / VTE 2
  • stroke risk / yr: CHADS 0 = 1.9%, 1 = 2.8%, 2 = 4%, 3 = 5.9%, 4 = 8.5%, 5 = 12.5%, 6 = 18.2%
CHA2DS2-VASc
  • CHF 1, HTN 1, ≥ 75 2, DM 1, Stroke/TIA /VTE 2, Vascular dz 1, 65-74 1, female 1
    • Vascular dz: prior MI, peripheral artery dz or aortic plaque
Risk of bleeding
  • HAS-BLEED:
    • HTN (sBP>160),
    • Abn Liver/Renal (Cr>200) (1 each),
    • Stroke,
    • Bleeding / anemia,
    • Labile INR (<60% therapeutic),
    • Elderly >65,
    • EtOH,
    • Drugs (ASA/NSAID/plavix)
  • HAS-BLED 0-2: warfarin, dabigatran (150), apixaban, rivaroxaban
  • HAS-BLED >2: dabigatran (110), apixaban, rivaroxaban, ASA
Temporary interruption for procedures, restart 24hr after the procedure
  • ASA or clopidogrel: 7-10 d prior
  • Warfarin 5 d prior
  • Dabigatran 2 d prior
  • If high risk of VTE – bridge with heparin

PowerPoint Presentation

  • CHADS2 ≥ 2 – OAC
  • CHADS2 = 1 – OAC or ASA (reasonable alternative)
  • CHADS2 = 0 – use CHA2DS2VASc
  • Recent ACS/PCI with CHADS2 =<1: ASA + Plavix
  • Recent ACS/PCI with CHADS2>=2: ASA + Plavix + OAC
  • CHA2DS2-VASc = 0 no antithrombotic Tx
  • CHA2DS2-VASc = 1 – ASA 75-325mg/d
  • CHA2DS2-VASc >1 (Age ≥ 65 or female with vascular dz) – OAC & ASA is a reasonable alternative
  • Exception: 
    • Warfarin for mechanical prosthetic valve, rheumatic mitral stenosis or eGFR =<30

 AF known onset =<48hr
  • Cardioversion – electrical / pharmacological
AF uncertain or ≥ 48hr – rate control or high risk pt:
  1. therapeutic OAC x 3 weeks –> cardioversion –> OAC x 4 weeks
    • use CHADS2 after if sinus rhythm sustained for 4 weeks, otherwise continue indefinitely
  2. TEE-guided cardioversion (OAC initiated with heparin bridging)

4 In patients with atrial fibrillation, when the decision has been made to use anticoagulation, institute the appropriate therapy and patient education, with a comprehensive follow-up plan.

  • When OAC is indicated, pt should receive dabigatran, rivaroxaban, apixaban in preference to warfarin in non-valvular A Fib with eGFR>=30

Major Goals of AF arrhythmia Tx
  • Improve functional capacity / quality of life / relieve symptoms
  • Improve LV function
  • Reduce morbidity / mortality associated with AF
    • Prevent tachycardia-induced cardiomyopathy
    • Reduce / prevent emergency room visits or hospitalizations due to AF
    • NO difference in mortality between rate and rhythm control
    • Rate control – less s/e, fewer hospital admissions
    • Rhythm control – pt feels better in sinus rhythm
  • Prevent Stroke or systemic thromboembolism

gr3


5 In a stable patient with atrial fibrillation, identify the need for rate control.

  • 1st line therapy (rhythm control is 2nd line) for maintenance tx unless highly symptomatic, multiple recurrences extreme impairment in QOL, arrhythmia induced cardiomyopathy
  • The goals of rate control should be to improve symptoms and clinical outcomes which are attributable to xs ventricular rates
  • For patients with recently dx symptomatic AF, rate control to keep the heart rate < 100 bpm seems an appropriate first step
  • Favoured if few symptoms, age >65, HTN, CAD, no CHF
  • The rate control approach consists of ventricular rate control, OAC, and delayed cardioversion after 4 weeks if indicated.
  1. CHF – b-blocker ± digoxin
  2. CAD – b-blocker, CCB, combination Rx
  3. No CHF / CAD – B-blocker, CCB, Digoxin, combination Rx
First line Tx for pt w/o hx of MI / LV dysfunction:
  1. Beta-blockers: Bisoprolol 2.5-10 mg po daily or Metoprolol 25-200mg po bid (Atenolol 50-150)
    • s/e: bradycardia, HoTN, fatigue, depression
  2. non-dihydropyridine CCB: Diltiazem 120-480 po daily (120-240 bid)
    • s/e: bradycardia, HoTN, ankle swelling
Digoxin 0.0625 mg – 0.25mg po daily
  • s/e: bradycardia, n/v, visual disturbance
  • reserved for rate control in pt who are sedentary or have LV systolic dysfunction
  • Added therapy with beta-blockers or CCB in pt whose heart rate remains uncontrolled.

6 In a stable patient with atrial fibrillation, arrange for rhythm correction when appropriate.

  • The goals of rhythm control should be to improve symptoms and clinical outcomes and these do not necessarily imply the elimination of all AF
  • Rhythm control for pt who remain symptomatic with rate control Tx, paroxysmal, age <65, no HTN, CHF exacerbated by AF or in whom rate control is unlikely to control symptoms.
  • Speical circumstances for early rhythm control:
    • Highly symptomatic
    • Multiple recurrences
    • Extreme impairment in QOL
    • Arrythmia-induced cardiomyopathy
  • The rhythm control approach is widely used in Canadian EDs
    • Thromboembolic event highest in patients with older age, heart failure, or diabetes.
    • For patients with no high-risk factors for stroke (recent stroke or TIA within 6 months; rheumatic heart disease; mechanical valve) and clear AF onset within 48 hours or therapeutic OAC therapy for ≥ 3 weeks, they may undergo cardioversion in the ED without immediate initiation of anticoagulation.
    • After attempted or successful cardioversion, antithrombotic therapy should be initiated as per the CCS algorithm

Slide 1

  • Maintenance oral antiarrhythia Tx for pt with recurrent AF in whom long-term rhythm control is desired
  • Intermittent antiarrhythmic Tx (“pill in pocket”) in symptomatic patients with infrequent, longer-lasting episodes of AF as an alternative to daily antiarrhythmic Tx
    • 1-2 episodes / year: Propafenone 450mg + metoprolol 25mg prn (takes 3-4 hr to work)
  1. Normal Systolic Function, no CHF (C/I in pt with CAD or LV dysfunction)
    • Flecainide 50-150mg po Bid / Propafenone 150-300 mg po tid with BB or ND-CCB
      • s/e: VT, bradycardia, rapid ventricular response to AF
      • use with b-blocker or ND-CCB
    • Sotalol – use with cation for those at risk for torsades de pointes VT (female, >65yo, taking diuretics, renal insufficiency,)
      • S/e: Torsades de pointes, bradycardia, beta-blocker s/e
      • Monitor QT 1wk after starting, caution if EF <40%
    • Amiodarone 100-200mg po (after 10g loading)
      • s/e: photosensitiity, bradycardia, GI upset, thyroid dysfunction, hepatic toxicity, neuropathy, tremor, pulmonary toxicity (pulm fibrosis), Torsades de pointes (rare)
      • do periodic LFTs and TSH
      • Low risk of proarrhythmia
      • Limited by systemic s/e – dose & duration related
  2. CHF, LV systolic dysfunction
    • EF>35%: Amiodarone, sotalol
    • EF ≤35%: Amiodarone
Catheter Ablation
  • Pt remain symptomatic following adequate trials of anti-arrhythmic Tx in whom a rhythm control strategy remains desired
  • Not an alt to anticoagulation – still need anticoagulation after successful catheter ablation
  • Typical pt profile:
    • <80yo, symptomatic
    • tried but failed / intolerant of antiarrhythmic drug Tx
    • paroxysmal AF or short-standing persistent AF
    • min-moderate structural heart dz (LV dysfunction or valvular dz)
  • 1st line for symptomatic pt with typical Atrial flutter

References:

http://www.onlinecjc.ca/article/S0828-282X(14)01249-5/pdf

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Posted in 8 A Fib, 99 Priority Topics, Cardiac, FM 99 priority topics
2 comments on “Atrial Fibrillation – CCS2014
  1. great information to know.

    Like

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