atrial fibrillation (AF)

Classification

• paroxysmal atrial fibrillation
  • intermittent, stops spontaneously within 7 days of onset
• persistent atrial fibrillation
  • persists for >= 7 days
• long-standing persistent last >= 1 year
• permanent refers to cases where any attempts to maintain sinus rhythm have been abandoned

Etiology

• hypertension, systolic hypertension
  • lowering systolic BP lowers risk of new-onset AF
• acute alcohol ingestion (holiday heart syndrome)
• ischemic heart disease
• myocardial infarction
• congestive heart failure
• valvular heart disease
  • mitral valve disease
    • mitral stenosis: rheumatic heart disease (diastolic murmur at apex)
    • mitral regurgitation (holosystolic murmur)
• pericarditis
• sick sinus syndrome
• pulmonary disease
  • pulmonary embolus
  • pneumonia
  • chronic obstructive pulmonary disease (COPD)
• s/p open heart surgery
• theophylline intoxication
• endocrinopathies
  • hypothyroidism
  • hyperthyroidism
    • even subclinical hyperthyroidism increases risk of atrial fibrillation
  • pheochromocytoma
• infections
• cardiac tumors: atrial myxoma
• substrate for acute atrial fibrillation
  • atrial scars from prior cardiac surgery
  • lung disease
  • chronic pressure overload
• triggers of acute atrial fibrillation
  • sepsis, volume changes, pericardial inflammation, thyrotoxicosis, medications
• risk factors -
  • obesity
    • obesity appears to be associated with electrical & structural changes in the heart that increase the risk of AF
    • weight reduction appears to lower that risk
  • diabetes mellitus (weak association)
  • high pulse pressure
  • advanced age
  • long-term endurance exercise (2-10 fold risk) due to left atrial enlargement
  • long-term glucocorticoids, as little as 7.5 mg of prednisone/day
  • chronic renal failure (HR=3.2 GFR <30 ml/min/1.73 m2)
    • albuminuria
  • premature atrial contractions (RR=1.2]
  • elevated resting heart rate (RR=1.1)
  • pharmaceutical & other drugs
    • NSAID & COX2 inhibitors
      • HR=1.2-1.3; HR=1.5-1.7 for new users
      • HR=1.7 for use in elderly
    • alcoholic beverage use, even in moderation increases risk
    • smoking
    • cocaine, methamphetamine, opioids, cannabis
    • marine omega-3 fatty acids supplementation > 1 gram/day
  • asthma (RR=1.4, RR=1.7 for uncontrolled asthma)
  • bereavement from death of a partner (RR=1.9)
  • neurogenic mechanism suggested for atrial fibrillation after ischemic stroke
  • sleep apnea
  • elevated plasma Lp(a) evidence conflicting

Epidemiology

• most common sustained arrhythmia
• prevalence is 96.2/1000 person-years in men & 49.4/1000 person-years in women
  • prevalence is 6.4% at 65-69 years & 28.5% at >= 85 years of age
• 50% of patients with AF are >= 75 years of age
  • AF affects 10-19% of Americans over age 75
• incidence is 14.2 per 1000 person-years at 65-69 years & 50.8 per 1000 person-years at >= 85 years
  • incidence is greater in men 33.4 per 1000 person-years vs women 16.8 per 1000 person-years
• > 98% of patients have comorbidity
• 14% increase in hospitalizations for atrial fibrillation 2000-2010
• lifetime risk 23% among persons with optimal risk factors
• recurrent atrial fibrillation occurs in 32% of patients with transient new-onset atrial fibrillation during hospitalization

Pathology

• multiple simultaneous wandering wave fronts of activation with simultaneously occurring reentrant circuits within the atria
• any disease process that increases atrial size (left atrial enlargement) &/or decreases atrial conduction or refractory period may result in AF
• the pulmonary veins have been implicated in generating the electrical current of AF
• atrial fibrillation may induce atrial cardiomyopathy
• resultant atrial cardiomyopathy promotes further atrial fibrillation
• subtle abnormalities in left ventricular function, not corrected by ablation with cardioversion described
• calcitonin is produced by atrial myocytes & diminishes production of collagen by atrial fibroblasts. [161
  • in mice, increasing atrial calcitonin production prevents fibrosis & atrial fibrillation
  • inhibiting calcitonin production enhances fibrosis & atrial fibrillation

Genetics

• familial atrial fibrillation associated with defect in: LMNA, KCNQ1, KCNE2, NPPA

Clinical manifestations

• may be asymptomatic
• palpitations
• irregular heart rate, irregularly irregular pulse
• dizziness
• dyspnea
• angina
• syncope
• heart failure
• systemic embolism
• no A wave in jugular venous pulse
• pulse deficit (auscultated pulse > palpated pulse, especially radial artery)
• variable S1 heart sound

Laboratory

• thyroid function tests
• theophylline level if indicated
• urinary metanephrines if indicated
• pulse oximetry
• digoxin level if possible exposure
• high levels of plasma GDF15 (median 1383 ng/L) associated with increased risk for major bleeding, mortality, & stroke (investigational)

Diagnostic procedures

• electrocardiogram
  • irregularly fluctuating baseline: atrial rate 350-600 bpm
  • no P waves
    • deformed T waves or ST segment may hide P waves
  • irregular spacing of R waves
  • a regular ventricular rate (regular spacing of R waves) suggests complete AV block with a junctional rhythm
  • wide complex tachycardia may occur with pre-excitation (WPW); look for delta wave
• echocardiogram
  • rule out valvular heart disease, i.e. mitral stenosis
  • assess left atrial size: an enlarged left atrium is unlikely to maintain sinus rhythm if cardiovertedy
• sleep study for evaluation of sleep apnea
• also see paroxysmal atrial fibrillation
• complex & costly screening protocols not required for detection

Staging

• stage 1: risk factors for atrial fibrillation
• stage 2: pre-atrial fibrillation because of structural or electrical findings
• stage 3: paraoxysmal atrial fibrillation
• stage 4: permanent atrial fibrillation

Complications

• rapid ventricular response
  • if unstable, immediate synchronized cardioversion
• potentially serious complications with
  • Wolf-Parkinson-White syndrome
  • aortic stenosis or mitral stenosis
    • need for atrial kick to maintain cardiac output
  • diastolic dysfunction
    • non compliant ventricle, impaired ventricular filling
    • cardiovascular collapse with rapid ventricular response
• thromboembolism (see risk factors for thromboembolism)
  • the majority of thromboembolic strokes occur in association with AF
  • stroke risk is 4%/year for untreated patients
    • estimated 1-year stroke risk for untreated patients 66 years of age is 0.7% increasing to 1.7% at 74 years
  • embolic stroke risk for patients on aspirin alone
    • 2%/year for low risk patients
    • 4%/year with any risk factor
    • as high as 18%/year for high risk patients
  • patients with resolved AF still at risk for stroke or TIA
    • 12.1 vs 7.4 per 1000 person-years (no AF) not as high as those with current AF (16.7 per 1000 person-years)
  • 2-fold risk of silent stroke
    • study unable to assess possible risk reduction with anticoagulation
  • 84% of patients with atrial fibrillation & ischemic/ embolic stroke with no or inadequate anticoagulation
  • > 90% of atrial thrombi in patients with non-valvular atrial fibrillation are believed to originate in the left atrial appendage
  • risk greater for women than men (independent of warfarin)
    • see CHADS2 score
    • risk not greater for lone atrial fibrillation
  • chronic renal failure increases risk of thromboembolism
  • thromocytopenia increases risk of thromboembolism
• perioperative atrial fibrillation associated with increased risk of atrial fibrillation after surgery
  • RR = 1.3 for cardiac surgery
  • RR = 2.0 for non-cardiac surgery
• hemorrhage associated with anticoagulation
  • has-bled score estimates risk
  • risk factors include
    • hypertension
    • renal insufficiency
    • abnormal liver function
    • prior stroke
    • history of bleeding or predisposition to bleeding
    • labile INR
    • age > 65
    • concurrent aspirin or NSAID
    • alcohol intake in excess of recommended limits
    • thromocytopenia associated with increased risk of bleeding & thromboembolism
  • restart of oral anticoagulation after GI bleeding is associated with reduced risk of thromboembolism & lower mortality
  • 1 year risk of colorectal cancer after lower GI bleed in patients anticoagulated for atrial fibrillation is similar to that for patients without atrial fibrillation or anticoagulation (3.7% < 65 years, 8.1% > 75 years)
• cognitive impairment & vascular dementia linked to atrial fibrillation
  • high prevalence of mild cognitive impairment in hospitalized elderly with chronic atrial fibrillation
  • association attenuated but not eliminated by excluding patients with heart failure
  • anticoagulation diminishes risk of dementia
  • rhythm control, especially catheter ablation may be best strategy to diminish risk of dementia
• increases risk of myocardial infarction (RR = 2)
  • increased risk for sudden cardiac death (0.6/1000)
• increased risk for heart failure (11.1/1000)
• increased risk for renal failure (6.6/1000)
• increased cardiovascular mortality (2.6/1000)
• newly diagnosed atrial fibrillation in women is associated with increased cancer risk (1.4% vs 0.8/year) & vice versa
• increased mortality (3.6/1000)
  • mortality risk associated with newly diagnosed atrial fibrillation has not changed for 1972-2015
• little correlation between estimated & patient perceived risk for stroke or hemorrhage
  • 1 in 5 patients believe anticoagulation lowers stroke risk by 90% (trials suggest risk reudction about 2/3)
  • almost all older adults > 64 years under-estimate bleeding risk
• increased risk of syncope & falls in the elderly

• disease interaction(s) of cirrhosis with atrial fibrillation
• disease interaction(s) of intracranial hemorrhage with atrial fibrillation
• disease interaction(s) of asthma with atrial fibrillation
• disease interaction(s) of atrial fibrillation with frailty
• disease interaction(s) of atrial fibrillation with dementia
• disease interaction(s) of atrial fibrillation with ischemic stroke
• disease interaction(s) of atrial fibrillation with myocardial infarction
• disease interaction(s) of atrial fibrillation with coronary artery disease
• disease interaction(s) of atrial fibrillation with chronic renal failure
• disease interaction(s) of atrial fibrillation with mitral stenosis
• disease interaction(s) of atrial fibrillation with heart failure

Differential diagnosis

• multifocal atrial tachycardia in COPD
• digitalis toxicity - atrial tachycardia with AV block
• preexitation tachycardia
• ventricular tachycardia
  • AF may appear as wide-complex tachycardia if intraventricular conduction delay (RBBB)

Management

• hemodynamics, rate control, ischemic symptoms, & anticoagulation are the common management concerns in newly diagnosed nonvalvular atrial fibrillation
• hospitalize for
  • hemodynamically unstable, prepare for cardioversion (see below)
  • high risk for thromboembolism
    • immediate anticoagulation with heparin & warfarin
• may be difficult to distinguish cardiogenic tachycardia (suppress) from tachycardia due to physiological needs (allow)
• assess intravascular volume & other noncardiac determinants of a rapid ventricular response prior to treatment
• correct precipitating causes (first line)
  • correct hyperthyroidism prior to cardioversion
  • correct hypovolemia
  • weight loss & intensification of exercise, especially when BMI > 27
    • AHA/ACC class 1 recommendation for newly diagnosed atrial fibrillation in addition to consideration of anticoagulation (see below)
• rate control formerly preferred strategy (exception WPW) (see below)

cardioversion

• DC cardioversion (50, 100, 200, 300, 360 joules)
  • more effective than chemical cardioversion
• chemical cardioversion
  • pharmacologic agents
    • class 1A, 1C or 3 antiarrhythmic agents
      • amiodarone & dronedarone formerly class 3 antiarrhythmics now antiarrhythmic multichannel blockers
        • useful for cardioversion & maintenance of sinus rhythm
      • adenosine is not effective
  • conversion & maintenance of sinus rhythm
• indications
  • urgent cardioversion if patient is unstable
    • hypotension
    • unstable angina, myocardial ischemia
    • acute heart failure
  • mitral stenosis
  • mitral regurgitation
  • new onset of atrial fibrillation within 48 hours
    • immediate cardioversion in the emergency department no better than cardioversion at 48 hours
  • early rhythm control (median time from diagnosis = 36 days) may be associated with better outcomes than rate control
  • patients with continued symptoms despite adequate rate control
• contraindications:
  • atrial thrombus: delay cardioversion until completion of 4-6 weeks of anticoagulation with warfarin
  • if patient is unstable, do not delay cardioversion for atrial thrombus, to check INR or any other reason
• anticoagulation
  • IV heparin prior to emergent cardioversion if duration of AF not known
  • 3 weeks prior to elective cardioversion
    • if atrial fibrillation < 48 hours, then may proceed with cardioversion without prior anticoagulation
    • trans-esophageal echocardiography (TEE) may be use to determine presence of atrial thrombosis; if none then may proceed with cardioversion without prior anticoagulation
  • edoxaban is as safe & effective as enoxaparin-warfarin
  • major bleeding less with dabigatran than warfarin (1.6% vs 6.9%) without difference in thrombosis
  • continue for 4 weeks after successful cardioversion

maintenance of sinus rhythm

• antiarrhythmic therapy for maintenance of sinus rhythm
  • rhythm-control strategies, especially ablation, are effective in protecting cognitive function, reducing dementia risk & improving quality of life
  • younger, symptomatic patients benefit more often than elderly
  • class III agents
    • amiodarone (most commonly used, formerly class 3 agent)
      • 400 mg for 30 days, then 200 mg QD
      • especially useful with structural heart disease
      • 1st line agent for AF if ischemic heart disease & LV dysfunction
      • symptomatic benefit only
    • sotalol in patients with CAD
    • dronedarone (Multaq)
  • class 1C agents, if no structural heart disease
    • flecainide 100 mg BID, or
    • propafenone 150-225 mg TID
  • 30-50% of patients will maintain sinus rhythm after 1-2 years
  • PRN flecainide or sotalol for paroxysmal atrial fibrillation
  • ranolazine (Ranexa)
    • may be useful for maintenance of sinus rhythm
    • may accelerate chemical cardioconversion with amiodarone
• observational study finds mortality benetit for rhythm control vs rate control at 5 years (RR = 0.89) & 8 years (RR = 0.77), but not at 6 months (RR = 1.07)
• lower risk for adverse outcomes with a rhythm-control strategy, but only when initiated within one year of diagnosis
• rhythm control associated with lower adverse cardiovascular risk than rate control in newly diagnosed patients with atrial fibrillation
• use of antiarrhythmic agents in patients with new onset atrial fibrillation increases risk of syncope (RR=2.0) & pacemaker placement (RR=5.0)

ablation

• ablation first line strategy for all LV ejection fractions
  • anticoagulation >= 3 weeks prior to ablation
  • AV node ablation with permanent ventricular pacing
    • refractory ventricular rate
  • radiofrequency ablation of focal atrial fibrillation in younger patients
  • catheter ablation for persistent or paroxysmal atrial fibrillation
    • reduces dementia & mortality vs rate control with anticoagulation in older patients (>= 65 years) with or without
      • left ventricular systolic dysfunction
      • left ventricular diastolic dysfunction
      • hypertension
      • diabetes mellitus
      • ischemic stroke
        • chronic kidney disease
    • reduces hospitalization for worsening heart failure in patients with HFrEF
  • radiofrequency ablation vs cryoablation
  • pulmonary vein isolation/ablation may become 1st line therapy
    • indicated if rhythm control needed & not achievable with antiarrhythmics (i.e. WPW)
    • more extensive ablation than pulmonary vein isolation alone does not result in better outcomes for patients with persistent atrial fibirllation
    • repeat ablations common 20-30%
  • residual cardiac arrhythmias in 1/2 of patients
  • risk of cardiac tamponade
  • maze procedure may be useful for patients undergoing cardiac surgery for other reasons
  • anticoagulation should continue for 2-3 months after ablation
  • continue warfarin past 2-3 months even in the absence of evidence of further atrial fibrillation if CHADs2 score >= 2
• left atrial appendage closure after ablation
  • noninferiority for preventing stroke (with lower bleeding risk) compared with anticoagulation
  • procedure-related adverse events (pericardial effusion, major bleeding, device embolization) in ~ 1 in 25 device-implanted patients
• anticoagulation after successful catheter ablation reduces risk of thromboembolism only in highest risk patients

rate control strategy

• control ventricular rate via AV nodal blocking agents formerly preferred strategy (excluding WPW)#
  • Ca+2-channel antagonists (NOT dihydropyridines)
    • diltiazem reduces frequency & severity of symptoms
      • diltiazem 360 mg/day PO appears to be the best choice
      • IV for rapid ventricular response
    • verapamil reduces frequency of symptoms
  • beta-blocker
    • metoprolol, atenolol, carvedilol
    • may not reduce either the frequency or severity of symptoms
    • may exacerbate symptoms of asthma or obstructive lung disease
  • digoxin (last resort, no other options)
    • not very effective in controlling ventricular response during exercise
    • add calcium channel antagonist or beta-blocker in patients controlled at rest, but with tachycardia during exercise
    • do not use as single agent for rate control
    • may be associated with higher mortality among patients with atrial fibrillation (RR= 1.2)
    • higher risk of toxicity in patients with renal failure
    • no difference in patient-reported quality of life vs beta blocker
  • lenient rate control (< 110/min) with outcomes similar to standard control (< 80/min)
  • diltiazem may be best choice (metabolized by liver)
  • symptomatic benefit only
• rate + rhythm control offers better symptom management than rate control alone

anticoagulation for rate control strategy

• anticoagulants reduce risk of ischemic stroke
• indications for anticoagulation
  • CHADS2 score >= 2 (men), >= 3 (women) (see CHADS score)
    • anticoagulation may be reasonable in men with CHADs score of 1 or women with CHADS score of 2
    • benefit of anticoagulation unlikely with CHADS2 score of 1
  • combination of anticoagulant & antiplatelet agent rarely indicated (see antiplatelet therapy below & Complications: above)
  • in patients with history of intracranial hemorrhage, threshold for CHADS2 score >= 6
  • transient ischemic attack
  • warfarin if hypertrophic cardiomyopathy regardless of CHADs score
  • only 1/3 of patients receive recommended anticoagulation
  • almost 40% of eligible patients do not receive oral anticoagulants
  • anticoagulation in patients with ESRD on dialysis
    • apixaban 5 mg BID is associated with a reduced risk of thromboembolism & mortality risk (GRS11 cites a 2018 paper) later questioned in a more recent 2020 paper (cited below)
    • anticoagulation is not associated with lower embolic risk in patients with ESRD on dialysis, but is associated with higher bleeding risk
  • anticoagulation in elderly > 75 years reduces 1.5 risk of dementia 12%
  • risks of anticoagulation for atrial fibrillation in demented frail elderly may exceed benefits
• direct oral anticoagulants (thrombin inhibitor, factor Xa inhibitor, DOAC)
  • preferred vs warfarin
    • MKSAP19 notes warfarin only FDA-approved agent for valvular AF
    • switching from warfatin to DOAC in frail elderly may result in increased risk of bleeding without benefit in thromboprophylaxis
  • more effective & safer than warfarin
    • reduced all-cause mortality relative to warfarin
    • better & safer than warfarin for stroke prevention in patients with bioprosthetic valvular atrial fibrillation [166, 184]
    • safer than warfarin in the very old
  • strongly recommended if therapeutic INR not achieved with warfarin
  • not for use in patients with mechanical heart valves or moderate to severe mitral stenosis
  • apixaban seems to be direct oral anticoagulant of choice
    • apixaban more effective & safer than rivaroxaban
  • continue 81 mg aspirin with DOAC if MI in past year
    • risk using pooled cohort equations not a consideration for dual therapy
• thrombin inhibitor (dabigatran)
  • FDA approved (2010) & included in AHA guidelines for treatment of atrial fibrillation
  • no need for therapeutic monitoring (INR)
  • superior to warfarin in Asians
  • lower risk of hospitalization for GI bleed & for intracranial hemorrhage than with rivaroxaban
  • less risk of osteoporotic fracture than with warfarin (0.7 vs 1.1 per 100 person-years)
  • higher risk of extracranial bleeding in patients > 75 years of age
  • check renal function
    • renal dosing not examined in clinical trials
    • renal dosing 110 mg BID associated with lower risk for hemorrhagic stroke than 70% warfarin dosing (RR=0.46)
• factor Xa inhibitor
  • rivaroxaban
    • not inferior to wafarin in preventing embolic stroke
    • superior to warfarin in Asians;reduced risks for ischemic stroke & systemic embolism,intracranial hemorrhage, & all-cause mortality at 1 year
    • higher risk of hospitalization for GI bleed & for intracranial hemorrhage than with dabigatran
  • apixaban
    • better than warfarin, regardless of number of concurrent medications
    • apixaban with lowest risk of GI bleed among DOACs
    • rates of ischemic stroke, systemic embolism, intracranial hemorrhage & all-cause mortality similar for apixaban, dabigatran, edoxaban, & rivaroxaban including for patients >= 80 years & those with chronic kidney disease
    • in patients with ESRD, apixaban associated with lower risk of major bleeding than warfarin, & with reductions in thromboembolism & mortality (dose 5 mg BID)
    • not associated with benefit in patients with ESRD on dialysis
    • alternative to warfarin in patients with end-stage renal disease
    • safe with close monitoring in patients with ESRD on dialysis (MKSAP19)
    • among Medicare recipients with atrial fibrillation >= 65 years, apixaban is associated with lower risk of major ischemic events & major hemorrhage than rivaroxaban
    • seems to be direct oral anticoagulant of choice
  • low-dose edoxaban 15 mg/day effective in reducing thromboembolism & stroke in elderly >80 years of age
  • check renal function
    • renal dosing of factor Xa inhibitor associated with increased mortality relative to 70% warfarin dosing (RR=0.1.48 for rivaroxaban & 1.23 for apixaban)
• warfarin - INR of 2.0-3.0 is therapeutic%
  • see risk factors for thromboembolism
  • anticoagulant of choice in patients with mechanical heart valve, or hypertrophic cardiomyopathy
    • MKSAP19 notes warfarin is only FDA-approved agent for valvular AF
  • reduces risk 50% & lessens severity of stroke
    • 50% of patients benefit from anticoagulation; patients with < 2 risk factors for stroke will not benefit
    • risk of stroke on warfarin;
      • 1.6%/year mean age 71
      • 2.6%/year mean age 81
  • in elderly (> 75 years of age), stroke scores with poor predictive value
  • in elderly (> 75 years of age), risk of hemorrhage is high
    • risk of major hemorrhage 10%/year
    • risk of life-threatening hemorrhage 5%/year,
    • risk of fatal hemorrhage 1%/year
  • increased risk of intracranial hemorrhage associated with INR > 3.5, age > 85
  • reduces overall mortality 4.5 vs 5.3 per 100 person years
  • reduces risk of mortality, MI & stroke in patients with chronic renal failure stage 3 & higher without increased risk of hemorrhage
    • treatment of choice in patients with chronic renal failure stage 5
    • increased risk of hemorrhage due to warfarin in patients with chronic renal failure
    • increased risk of ischemic stroke (RR=2.6), hemorrhage (RR=2.4) but decreased mortality (RR=0.8) relative to no anticoagulation in patients with chronic renal failure (GFR < 50 mL/min)
    • warfarin may cause more harm than benefit in patients with end-stage renal disease
    • warfarin of no benefit in preventing thromboembolism when GFR < 15 mL/min/1.73 m2
  • low risk of bleeding (2%), in elderly <same as aspirin>
  • risk or bleeding inversely associated with kidney function in older adults
    • ineffective, even harmful in patients with ESRD
  • risk schemes to predict warfarin-associated hemorrhage described in
  • warfarin may paradoxically increase risk of ischemic stroke during initiation of therapy by inhibition of endogenous anticoagulants
  • addition of aspirin to warfarin may not reduce risk of myocardial infarction in patients with stable coronary artery disease
    • no data after cororary revascularization
  • restart warfarin 7 days after major gastrointestinal bleed
    • not associated with increased risk of GI bleed
    • associated with reduced risk of thromboembolim & mortality relative to restarting at 30 days
• comparisons of direct oral anticoagulants with warfarin
  • stroke rate similar for dabigatran, rivaroxaban & warfarin, regardless of comorbidites
  • rivaroxaban with higher rate of major hemorrhage than dabigatran & higher rate of GI bleeding than warfarin in patients with comorbidites
  • mortality lower with dabigatran & rivaroxaban than with warfarin regardless of comorbidites
  • apixaban & dabigatran more effective than warfarin in preventing embolic stroke; rivaroxaban & edoxaban with efficacy similar to warfarin
  • apixaban & edoxaban associated with less bleeding than warfarin; dabigatran & rivaroxaban similar to warfarin
  • factor Xa inhibitors (apixaban, edoxaban, rivaroxaban) associatedwith less hemorrhagic stroke, intracranial bleeding, & lower all-cause mortality than warfarin
  • rivaroxaban noninferior to warfarin for prevention of stroke or systemic embolism & is associated with less intracranial hemorrhage or fatal bleeding
  • direct oral anticoagulants safer & more effective than warfarin for preventing reinfarction or bleeding in patients >= 75 years with prior stroke
• patients should continue anticoagulation during dental procedures & dermatologic procedures

*

• CAUTION
  • concurrent use of SSRI with oral anticoagulants among patients with atrial fibrillation further increases risk of bleeding

anticoagulation in renal failure

• warfarin
  • reduces risk of mortality, MI & stroke in patients with chronic renal failure stage 3 & higher without increased risk of hemorrhage
    • treatment of choice in patients with chronic renal failure stage 5
    • increased risk of hemorrhage due to warfarin in patients with chronic renal failure
    • increased risk of ischemic stroke (RR=2.6), hemorrhage (RR=2.4) but decreased mortality (RR=0.8) relative to no anticoagulation in patients with chronic renal failure (GFR < 50 mL/min)
    • warfarin may cause more harm than benefit in patients with end-stage renal disease
    • warfarin of no benefit in preventing thromboembolism when GFR < 15 mL/min/1.73 m2
• apixaban
  • in patients with ESRD, apixaban associated with lower risk of major bleeding than warfarin, & with reductions in thromboembolism & mortality (dose 5 mg BID)
  • not associated with benefit in patients with ESRD on dialysis
  • alternative to warfarin in patients with end-stage renal disease
  • safe with close monitoring in patients with ESRD on dialysis (MKSAP19)

antiplatelet therapy

• see coronary stent for patients with atrial fibrillation who undergo PCI with coronary stenting
• aspirin 81-325 mg PO QD
  • no longer recommended for prevention of thromboembolism in patients with atrial fibrillation
    • continue low-dose aspirin with DOAC if MI in past year
  • formerly recommended for elderly with CHADS2 score of 1
  • when harms of anticoagulation in frail cognitively impaired elderly are deemed unacceptable, many receive aspirin rather than nothing
  • ref recommends changing warfarin to aspirin 81 mg QD for elderly with GI bleed, creatinine clearance 15-30 ml/min, INR therapeutic
    • renal dosing of dabigatran considered not indicated
    • no mention of apixaban
    • no mention of acid suppression with proton pump inhibitor
  • NSAIDs are associated with increased risks for bleeding & thromboembolism in patients with atrial fibrillation
    • increased risk with or without anticoagulation
• clopidogrel no better than aspirin
• clopidogrel + aspirin
  • inferior to warfarin
  • better than aspirin alone but associated with increased risk of GI bleed (see ACTIVE A trial)
  • may be a reasonable alternative to aspirin alone in the occasional high-risk patient who cannot be treated with anticoagulation
• anticoagulation + P2Y12 receptor inhibitor (without aspirin) if coronary stent
• anticoagulation alone for AF + chronic stable CAD
  • warfarin plus antiplatelet agent substantially increases risk of bleeding, & risk outweighs any potential benefit
• for older adults with atrial fibrillation & acute MI who undergo PCI, treatment with dual antiplatelet therapy (DAPT) plus warfarin (triple therapy) of no benefit over DAPT alone & may increase risk of bleeding

cardiac pacemaker

• sick sinus syndrome accompanying AF
• symptomatic patients with paroxysmal AF

elective surgery

• target ventricular response for patients with chronic atrial fibrillation to undergo elective surgery is < 110/min
• see direct oral anticoagulant vs warfarin or perioperative anticoagulation if patient anticoagulated

diet & lifestyle changes

• weight reduction >= 10% in obese or overweight patients
• moderate physical activity can improve quality of life
• limit alcohol consumption as this may trigger or exacerbate atrial fibrillation
  • no recommendation to discontinue alcohol

prevention of atrial fibrillation

• control hypertension
• control weight
• smoking cessation
• treatment of sleep apnea may be of benefit
• chocolate may be of benefit
• fish oil (840 mg of omega-3 fatty acids EPA/DHA) &/or vitamin D (2000 IU/day) of no benefit in preventing atrial fibrillation
• fish oil of no benefit in preventing post-operative atrial fibrillation

screening for atrial fibrillation

• palpating pulse most cost effective means
• USPSTF finds insufficient evidence to recommend for or against screening for atrial fibrillation with ECG

wearable devices

• use of smartwatches or other wearable devices that measure pulse & detect arrhythmias is associated with increased follow-up health care use

prognosis

• mortality for hospitalization due to AF = 1%
• recurrent atrial fibrillation occurs in 32% of patients with transient new-onset atrial fibrillation during hospitalization
• in-home nursing visit 7-14 days after hospital discharge with multidisciplinary support as needed
  • does not prevent death or hospital readmission
  • shortens duration of subsequent hospitalization

* aspirin may not be effective in patients > 75 years of age

# in patients with WPW, rhythm control is indicated; procainamide is the drug of choice (see Wolf-Parkinson-White syndrome)

% exception is rheumatic heart disease, INR=2.5-3.5

More general terms

• supraventricular arrhythmia
• chronic cardiac arrhythmia
• fibrillation

More specific terms

• paroxysmal atrial fibrillation (PAF)
• postoperative atrial fibrillation; perioperative atrial fibrillation
• silent atrial fibrillation; atrial high-rate episodes

Additional terms

• ablation for atrial fibrillation; pulmonary vein isolation/ablation
• Atrial Fibrillation Follow-up Investigator of Rhythm Management (AFFIRM)
• Atrial Fibrillation Suppression Trial (AFIST)
• atrial flutter
• cardiac conduction system
• cardioversion
• pharmaceutical agents for treatment of atrial fibrillation
• risk factors for thromboembolism associated with atrial fibrillation
• Wolff-Parkinson-White (WPW) syndrome

Patient information

atrial fibrillation patient information

Database

• OMIM: https://mirror.omim.org/entry/607554
• OMIM: https://mirror.omim.org/entry/612201