Diagnostic yield of actionable arrhythmias in patients referred with syncope and collapse using ePatch extended holter

Abstract Background/Introduction Cardiac syncope commonly points to a potentially lethal disease process and carries one-year mortality up to 30%. Current guidelines on management of syncope suggest choosing ambulatory monitoring modality based upon the likelihood of symptoms during the monitoring period and is frequently undertaken with short duration (0-2 days) or extended wear Holter (EWH) monitoring (3-14 days). Purpose Determine the diagnostic yield (DY) of actionable arrhythmias (AA) in patients referred for syncope and collapse prescribed short or extended ambulatory monitoring. Methods A retrospective analysis was conducted for patients wearing the Philips ePatch between July 1st, 2022, and June 30th, 2023, with ICD-10 referral code R55 (Syncope and Collapse). Monitoring duration was grouped by 0-2, 3-7, and 8-14 days of wear time. Wear time was defined as number of hours with analysable ECG data. Arrhythmia detection was defined as either non-AA (did not meet urgent or emergent criteria) or AA (met urgent and/or emergent criteria). Urgent criteria were defined as Atrial Fibrillation/Flutter (>10 seconds), Ventricular Tachycardia (>100 BPM for >3 beats), Severe Tachycardia (>170 BPM for ≥30 seconds), Pause/Asystole (≥3 seconds), Severe Bradycardia (<35 BPM), and 2nd Degree or Higher AV Block. Emergent criteria were defined as VT (>100 BPM for ≥30 beats), Severe Tachycardia (≥220 BPM for ≥30 seconds), Pause/Asystole (≥10 seconds), and Severe Bradycardia (<20 BPM). Results The DY for any urgent and/or emergent AA was 6.8%, 11.0%, and 20.4% at 0-2, 3-7 and 8-14 days of wear time, respectively (p<0.00001 for all). For urgent AA, DY increased 1.6X at 3-7 vs 0-2 days, 1.9X at 8-14 vs 3-7 days and 3X at 8-14 vs 0-2 days of wear time (p<0.05 for all); for emergent AA, the DY increased 5X at 3-7 vs 0-2 days, 1.6X at 8-14 vs 3-7 days, and 8.2X at 8-14 vs 0-2 days of wear time (p<0.05 for all) (Graph 1). When examining tachyarrhythmias vs bradyarrhythmias, similar multiplicative yields in AA were noted between short, intermediate, and extended duration monitoring; statistical significance was noted for all arrhythmia subtypes (p<0.01), except for Severe Tachycardia and Bradycardia which were not significant between 0-2 and 3-7 days of wear time (Graph 2). Conclusion(s) In patients referred for ambulatory monitoring with syncope and collapse, urgent and emergent actionable arrhythmias increase significantly when extending from short to intermediate to long duration monitoring, with both tachyarrhythmias and bradyarrhythmias demonstrating similar increases in occurrence. Accordingly, EWH monitoring in patients referred with syncope and collapse has greater potential to identify arrhythmic aetiologies than use of standard duration Holter.