Atrial FibrillationHow to Manage Safely in the Emergency Room
Joseph G Akar, MD, PhD Associate Professor of Medicine
Director, Cardiac Electrophysiology Laboratory
The Mechanics •Deep sedation •Direct current cardioversion (DCCV)
•Synchronized shock •200-360 j •Safest and most effective procedure in all of medicine…as long as you take into account the risk of stroke
Clinical Case 1 67 year old female with HTN developed AF during routine stress test. HR 130 bpm. Sent to ED for management.
Decisions: •Cardiovert or Rate-control?
•Perform a TEE or not? •Anticoagulate or not? •How long to anticoagulate
Clinical Case 2 28 year old male with Crohn’s disease found to be in asymptomatic AF at time of colonoscopy for GI bleeding. HR 130 bpm. Sent to ED for management.
Decisions:
•Cardiovert or Rate-control? •Perform a TEE or not? •Anticoagulate or not?
•How long to anticoagulate
The Big Question in the Emergency Room What is the difference between the long-term risk of stroke in AF versus the risk of stroke after cardioversion?
“Virchow’s Triad”
Circa 1856 Interrupted blood flow
Modern interpretation Vessel damage
Blood stasis
Endothelial damage
Thrombosis
Thrombosis
Abnormal coagulation
Hypercoagulability
Comorbid •↑ D-Dimer • TAT and PF1.2 Conditions • vWF ↓ Shear Stress
Blood Stasis Inflammation • CRP • TNF-a • IL-1b • IL-6
Atrial Fibrillation
Platelet Activation • P-selectin • platelet factor 4 • b thromboglobulin • platelet microparticle
Cross-Linked Fibrin Clot
PAI-1
Endothelial Dysfunction
↓ NO
Extrinsic and Intrinsic Pathway Activation Prothrombin → Thrombin
Fibrinogen
Endothelial Damage • VEGF
• TF •↓ NO • vWF
Long-Term Risk of Stroke in Patients With AF The CHADS2 Score Stroke Risk Factors
Score
Congestive heart failure Hypertension Age >75 yrs Diabetes mellitus Stroke/TIA
1 1 1 1 2
Patients (N=1733)
Adjusted Stroke Rate (%/y) (95% CI)
120 463 523 337 220 65 5
1.9 (1.2 to 3.0) 2.8 (2.0 to 3.8) 4.0 (3.1 to 5.1) 5.9 (4.6 to 7.3) 8.5 (6.3 to 11.3) 12.5 (8.2 to 17.5) 18.2 (10/5 to 27.4)
*Mitral stenosis: warfarin
Modified from Fuster, V. et al. J Am Coll Cardiol 2006;48:e149-e246
CHADS2 Score 0 1 2 3 4 5 6
Treatment ASA alone ASA or Anticoag Anticoagulant Anticoagulant Anticoagulant Anticoagulant Anticoagulant
*Mechanical prosthetic valve: warfarin, INR>2.5
Long-Term Risk of Stroke in Patients With AF The CHA2DS2 –VASc Score Stroke Risk Factors Congestive heart failure/LV dysfunction Hypertension Age ≥75 yrs Diabetes mellitus Stroke/TIA/TE Vascular disease (prior MI, PAD, or aortic plaque) Age 65–74 years Sex category (i.e., female sex)
Score 1 1 2 1 2 1 1 1
For a score >1: oral anticoagulation (e.g., warfarin) For a score = 1: either as oral anticoagulation or aspirin 75 to 325 mg daily (oral anticoagulation is preferred ) For a score = 0: either aspirin 75 to 325 mg daily or no antithrombotic therapy can be used (no antithrombotic therapy may be preferred) From Lip GY et al. Chest 2010;137:263–72 and Marinigh R et al. J Am Coll Cardiol 2010; 56:827–37
Short-Term Risk of Stroke After Cardioversion ↓ Shear Stress
Endothelial Dysfunction
Blood Stasis
Cross-Linked Fibrin Clot
PAI-1 ↓ NO
Prothrombin F1.2
Extrinsic Pathway Prothrombin → Thrombin TAT
Fibrinogen
Stasis
Left Atrial Stunning Electro-mechanical dissociation following cardioversion
Atrial Flutter
Sparks PB et al. J Am Coll Cardiol. 1998;32(2):468475
Immediately after restoration of NSR
3 weeks after restoration of NSR
Sinus Rhythm
3 months AF
Akar et al, J Cardiovasc Electrophysiol 2002; 1027-1034
1 week after NSR
AF < 2 weeks
AF 2-6 weeks
Manning WJ et al. J Am Coll Cardiol. 1994;23(7):1535-1540.
AF > 6 weeks
Berger M et al. Am J Cardiol. 1998;82(12):1545-1547
Conclusions •Risk of stroke after DCCV is completely different from long-term risk of stroke •Risk of stroke after DCCV is primarily related to duration of AF •For AF duration < 48 hrs •DCCV can be performed without a TEE
•No need for anticoagulation after DCCV •If AF duration is > 48 hrs (or unknown) •TEE needed if patient not on therapeutic antocoagulation x 3 weeks
•Anticoagulation is absolutely needed x 4 weeks
Common Myths
•Atrial flutter carries less stroke risk that AF •Pharmacological cardioversion carries less stroke risk than electrical cardioversion
•Spontaneous conversion carries less stroke than cardioversion
Common Myth: Low Intensity Anticoagulation is OK â&#x20AC;˘Target INR is 2.0-3.0 â&#x20AC;˘Strokes in patients with sub-therapeutic INR are more likely to result in disability and death
Fuster, V. et al. J Am Coll Cardiol 2006;48:e149-e246
Hylek EM et al. N Engl J Med 2003; 349:1024
Unanswered Questions
•Do you need a TEE before cardioversion of a patient on novel anticoagulant (Dabigatran, Rivaroxaban, Apixaban)? •Do you need a TEE before cardioversion of a patient who had undergone surgical left atrial appendage closure/removal? •Do you need a TEE before cardioversion of a patient who had undergone left atrial appendage occluder?
Clinical Case 1 67 year old female with HTN and palpitations developed AF during routine stress test. HR 130 bpm. Sent to ED for management.
Decisions: •Cardiovert or Rate-control?
Cardiovert
•Perform a TEE or not?
No TEE
•Anticoagulate or not?
Anticoagulate
•How long to anticoagulate
Indefinitely
Clinical Case 2 28 year old male with Crohn’s disease found to be in asymptomatic AF at time of colonoscopy for GI bleeding. HR 130 bpm. Sent to ED for management.
Decisions:
•Cardiovert or Rate-control?
Rate control
•Perform a TEE or not?
No
•Anticoagulate or not?
No
•How long to anticoagulate
ECASA when acceptable