Atrial fibrillation (main): Difference between revisions

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==Work-Up==
==Work-Up==
*ECG
*[[ECG]]
*Digoxin level (if appropriate)
*Digoxin level (if appropriate)
*Chem-10
*Chem-10
*Magnesium level
*Magnesium level
*TSH & free T4 (AF increased in subclinical hyperthyrodism)
*TSH & free T4 (AF increased in subclinical hyperthyrodism)
*Eval for ACS only in:
*Eval for [[ACS]] only in:
**Pt with ECG changes suggestive of ischemia, hypotension, angina
**Pt with ECG changes suggestive of ischemia, hypotension, angina
**AF is rarely only manifestation of ACS, although RVR and hypotension can provoke demand ischemia
**AF is rarely only manifestation of ACS, although RVR and hypotension can provoke demand ischemia

Revision as of 23:34, 19 March 2016

Background

Atrial fibrillation categories[1]

Atrial Fibrillation Category Definition
Paroxysmal
  • Terminates spontaneously or with intervention within 7 days of onset.
  • Episodes may recur with variable frequency.
Persistent
  • Continuous sustained >7 days
Long-standing persistent
  • Continuous >12 mo in duration.
Permanent
  • Used when the patient and clinician make a joint decision to stop further attempts to restore and/or maintain sinus rhythm.
  • Acceptance represents a therapeutic attitude on the part of the patient and clinician rather than an inherent pathophysiological attribute.
  • May change as symptoms, efficacy of therapeutic interventions, and patient and clinician preferences evolve.
Nonvalvular
  • In the absence of rheumatic mitral stenosis, a mechanical or bioprosthetic heart valve, or mitral valve repair.
With Rapid Ventricular Response (RVR)
  • With persistent ventricular heart rate >100 beats per minute

Causes of atrial fibrillation

Atrial fibrillation at approximately 150 beats per minute

Clinical Features

Differential Diagnosis

Palpitations

Diagnosis

  • 3 patterns on ECG:
  1. Typical
    • Irregularly, irregular R waves
    • QRS rate 140-160/min
  2. Large fibrillatory waves
    • May look like flutter waves
      • Unlike a-flutter, the fibrillatory waves are irregular
  3. Slow, regular A-fib
    • Due to complete AV block with escape rhythm
  • Ischemic changes?
  • Rate > 250? (think preexcitation)

Work-Up

  • ECG
  • Digoxin level (if appropriate)
  • Chem-10
  • Magnesium level
  • TSH & free T4 (AF increased in subclinical hyperthyrodism)
  • Eval for ACS only in:
    • Pt with ECG changes suggestive of ischemia, hypotension, angina
    • AF is rarely only manifestation of ACS, although RVR and hypotension can provoke demand ischemia
  • Bedside echo if available can provide info in LV function and underlying structural abnormalities

Management

  • Rate control
    • See: Atrial fibrillation with RVR
    • May observe with cardiac monitoring for 24 hrs without rate control meds if holiday heart syndrome[2]
    • Past 24 hrs, pts remaining tachycardic will require rate control
  • Anti-thrombotic therapy
    • Chronic and paroxysmal a fib are associated with thrombus formation
    • Contraindications to warfarin include alcoholism, recent trauma/surgery, active GI/GU/resp bleed, prior ICH while on OAC, suspected aortic dissection, malignant hypertension, high risk for falls.

CHADS2-VAsc Score

Risk Factor Points
CHF 1
HTN 1
DM 1
Previous stroke/TIA 2
Vascular disease (e.g. IHD, PVD) 1
Female gender 1
Age
≥ 75 years old 2
65 to 74 years old 1
  • Score 0: consider no treatment or ASA
  • Score 1: consider warfarin or ASA
  • Score 2-6: consider warfarin (INR goal = 2-3)
  • All patients with significant valvular disease should be on anticoagulation

HAS-BLED[3]

  • Used to assess 1 yr risk of bleeding on OAC medications
Risk Factor Point
Hypertension 1
Abnormal renal and/or hepatic function 1 point each
Stroke 1
Bleeding tendency/predisposition 1
Labile INR on warfarin 1
Elderly (age >65 years) 1
Drugs (aspirin or NSAIDs) and/or alcohol 1 point each
  • Score 1: 1.0 bleeds per 100 patient-years
  • Score 2: 1.9 bleeds per 100 patient-years
  • Score 3: 3.7 bleeds per 100 patient-years
  • Score 4: 8.7 bleeds per 100 patient-years
  • Score 5-9: Insufficient Data

Anticoagulation in Atrial Fibrillation/Flutter

Anticoagulation Therapy

  • ACCP Recommendations
    • In patients with AF, including those with paroxysmal AF, with only one of the risk factors listed immediately above, we recommend long-term antithrombotic therapy (Grade 1A), either as anticoagulation with an oral VKA, such as warfarin (Grade 1A), or as aspirin, at a dose of 75-325 mg/d (Grade 1B)[4]
    • In patients with AF, including those with paroxysmal AF, who have two or more of the risk factors we recommend long-term anticoagulation with an oral VKA (Grade 1A).[4]
  • CCS Recommendations
    • Oral anticoagulants are recommended for all AF patients aged 65 or older or who have any one of the traditional CHADS2 risk factors of stroke, hypertension, heart failure, or diabetes (remember as CHADS-65). Otherwise, patients with a history of coronary artery disease or arterial vascular disease should be prescribed ASA. CCS recommends that the first choice for oral anticoagulation should be the novel direct-acting oral anticoagulants (i.e. NOACs, for non-valvular AF). The big paradigm change is that ED physicians should prescribe OACs to at-risk AF patients before they leave the ED.[5]

Disposition

  • Similar outcomes for Canadian vs. American strategies, despite lower admission rates in Canada[6]

Canadian

  • "Limit hospital admission to highly symptomatic patients in whom adequate rate control cannot be achived"[7]

American

Indications for hospitalization:

  • Pt with acute heart failure or hypotension after rhythm or rate control
  • AF 2/2 HTN, infection, COPD exacerbation, PE, ACS/MI
  • Age > 60 (high risk of thromboembolism, more likely to have comorbidities)
  • Initiation of heparin or other anticoagulant
  • If considering ablation of accessory pathway in pt with AF
  • Symptomatic recurrence in the ED
  • Hemodynamic instability

Indications for discharge (low-risk pts): Discharge with urgent cardiology f/u

  • <60 years old
  • No significant comorbid disease
  • No clinical suspicion for PE or MI
  • Conversion in ED or rate control

Complications

  • Hemodynamic compromise
    • A-fib lowers CO by 20-30%
    • Impaired coronary blood flow
  • Arrhythmogenesis
  • Arterial thromboembolism

See Also

References

  1. 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation: Executive Summary. J Am Coll Cardiol. 2014;64(21):2246-2280. doi:10.1016/j.jacc.2014.03.021
  2. Yealy DM, Delbridge TR: Dysrhythmias, in Marx JA, Hockberger RS, Walls RM, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 7. St. Louis, Mosby, Inc., 2010, (Ch) 77:p 1010-1012.
  3. Pisters R, Lane DA, Nieuwlaat R, et al. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey. Chest 2010; 138:1093.
  4. 4.0 4.1 Singer DE et al. Antithrombotic therapy in atrial fibrillation: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition).Chest. 2008 Jun;133(6 Suppl):546S-592S
  5. Verma A, et al. 2014 Focused Update of the Canadian Cardiovascular Society Guidelines for the Management of Atrial Fibrillation Canadian Journal of Cardiology 30 (2014) 1114e1130
  6. Rising KL. Home is Where the Heart Is. Annals of Emergency Medicine. 2013;62(6):578-579
  7. Stiell, et al. Atrial Fibrilation Guidelines. Canadian Cardiovascular Society Atrial Fibrillation Guidelines 2010: management of recent-onset atrial fibrilation and flutter in the emergency department. Can J Cardiolol. 2011;27:38-46