paroxysmal atrial fibrillation (PAF)

Introduction

Atrial fibrillation that occurs episodically or in paroxysms.

It stops spontaneously within 7 days of onset.

Labeled stage 3 atrial fibrillation

Epidemiology

• ~1/3 of high-risk patients with subclinical episodes of atrial fibrillation
  • predictors of subclinical epsiodes of atrial fibrillation include: older age, left atrial enlargement, lower systolic BP

Clinical manifestations

• episodes may be symptomatic, especially in patients with LV diastolic dysfunction, or asymptomatic (subclinical)
• patients may be able to detect rhythm irregularity by monitoring their own pulse
  • in one study, pulse measurements by relatives & competent patients had reasonable sensitivity & specificity compared with clinicians for detecting atrial fibirllation
    • clinicians: sensitivity of 97%, specificity of 94%
    • relatives: sensitivity of 77%, specificity of 93%
    • patients: sensitivity of 54%, specificity of 96%
• short asymptomatic episodes of paroxysmal atrial fibrillation, may occur in patients with dual-chamber pacemakers or implantable cardioverter-defibrillators (ICDs)
• smartphone applications can detect asymptomatic episodes of paroxysmal atrial fibrillation
• Fitbit can detect irregular heart rate
  • subsequent use of an ambulatory electrocardiogram patch can detect paroxysmal atrial fibrillation

Diagnostic procedures

• in patients with cryptogenic stroke, HOLTER monitoring for a week or longer may identify patients with PAF
• home-based wearable ECG monitoring results in higher rate of paroxysmal atrial fibrillation diagnosis in high-risk individuals at 4 months
• annual 30-day monitoring with sensitivity of 34% for 1 year & 55% for 3 years in detecting paroxysmal atrial fibrillation

Complications

• progression to chronic atrial fibrillation (9% in 1 year; 25% in 5 years; risk increases with age)
• increases risk for ischemic stroke* (HR=5.6)
  • absolute risk appears to be 1.5% over 5 years with median time to stroke of 8 months after ECG confirmation
  • excess stroke risk highest within 5 days of an episode of atrial fibrillation of >= 5.5 hours & diminishes rapidly thereafter
  • episodes of atrial fibrillation > 5 minutes increase risk of systemic embolic events
  • more time spent in atrial fibrillation associated with higher risk of embolic stroke
  • short bursts of atrial fibrillation not associated with systemic embolic events
• progression of subclinical paroxysmal atrial fibrillation may be a harbinger of heart failure
• perioperative atrial fibrillation common, associated with similar risks for venous thromboembolism as new-onset atrial fibrillation & with similar crude rates of thromboembolism
• rapid ventricular response
  • if unstable, immediate synchronized cardioversion

* cryptogenic stroke

Management

• anticoagulation & rhythm control (see atrial fibrillation)
  • calculate the CHA2DS2-VASc score, if 0 no anticoagulation
• rhythm control for patients with new diagnosis within past 12 months or more
• atrial fibrillation duration of > 5 minutes & CHA2DS2-VASc scores >= 2 (men) >= 3 (women) would benefit from anticoagulation
• for device-detected atrial fibrillation lasting < 24 hours, risk of major bleeding outweighs risk reduction with anticoagulation for embolic stroke
• in patients with structural heart disease or major comorbidities, treat as symptomatic atrial fibrillation
  • cryoablation first line vs antiarrhythmic therapy
    • reduces risk for persistent atrial fibrillation vs antiarrhythmic therapy
  • radiofrequency catheter ablation
    • favorable effect on morbidity & mortality in patients with HFrEF
    • pulmonary vein ablation
      • risk of complications exceeds benefit, relative to antiarrhythmic agents
    • pulse field ablation
    • see atrial fibriallation
• pill-in-the-pocket may be appropriate for selected patients [1 ,2]
  • for transient, incidentally discovered atrial fibrillation, bleeding from anticoagulation about same as strokes prevented (< 2% in 3.5 years, comparison apixaban vs aspirin, mortality 18% both groups)
• fish oil 2 grams/day may suppress PAF (67% reduction)
  • marine omega-3 fatty acids supplementation > 1 gram/day may increase risk of atrial fibrillation
• abstinence from alcohol reduces recurrences of atrial fibrillation lasting > 30 seconds (53% vs 73% ) & % of time spent in atrial fibrillation (0.5% vs 1.2%)
• 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

More general terms

• atrial fibrillation (AF)