Comparison of simultaneous two-day external loop recording and - - PowerPoint PPT Presentation

Comparison of simultaneous two-day external loop recording and Holter monitor recording for detection of atrial fibrillation in patients after acute ischemic stroke or transient ischemic attack

Michala Herskind Sejr 1 , Ole May 1 , Dorte Damgaard 2 , Birgitte Sandal 3 , Jens Cosedis Nielsen 4 Cardiovascular Research Unit 1 and Department of Neurology 3, Regional Hospital West Jutland Department of Cardiology 4 and Department of Neurology 2, Aarhus University Hospital, Aarhus University, Denmark

Stroke and Atrial Fibrillation ~ 20% strokes are due to AF OAC reduces risk of stroke 60% in AF patients Short-term ECG recording + ECG ≥ 72 hours 30-day ECG monitoring of patients after stroke

Holter recording

• Gold standard
• 4 electrodes
• 2-lead continuous ECG
• Analysis is time consuming

External loop-recorder (ELR)

• Up to 32-day monitoring
• 2 electrodes
• 1 lead short ECG recordings
• Automatic AF detection

We aimed to determine sensitivity, specificity and positive predictive value of AF detection using two-day external loop recorder (ELR) monitoring against the gold standard of Holter recording

• ELR/Holter started simultaneously
• Endpoint: AF ≥ 30 sec.
• Holter as gold standard
• Blinded adjucation
• Exact McNemars test

Methods and statistics

Power Calculation

• Assumptions:

– ELR detects only AF also detected on Holter recording – Expected Holter detection of AF in 10% of patients – Holter recording detects 1.5% more patients with AF than ELR

• Power and sample size:

– Inclusion of 1,500 patients results in power of 83% to conclude that the true difference between recording methods is lower than 2.5% – Sample size calculation was based on 2-sided p-value of 0.05

Patient cohort TIA (n = 1,307) Ischemic stroke (n = 4,018) Total (n = 5,325) Screened (n = 5,325) Completed two- day Holter/ELR (n = 1,412) Enrolled (n = 1,507) Patients excluded: Prior participation Known AF AF on 12-lead ECG Holter after 1 week Low compliance Pacemaker Active cancer Did not want to participate (n = 3,818) Excluded: ELR started incorrectly (n = 95)

Population characteristics

• Included June 2013 to December 2017
• Ischemic stroke / TIA within one week
• Age ≥ 60 years
• No prior AF or AF in 12-lead ECG

 Age 72.8 years (SD 7.8)  797 ♂ (56%)  Ischemic stroke (60%) or TIA (40%)  Hypertension 825 (58.4%)  Diabetes 202 (14.3%)

AF in Holter No AF in Holter T

• tal

AF detected by ELR 35 184 219 (15.5%) No AF detected by ELR 3 1,190 1193 T

• tal

38 (2.7%) 1,374 1,412

Sensitivity: 82.1% Specificity: 86.6% PPV: 16.1%

Results

P-value=<0.0001

AF in Holter No AF in Holter T

• tal

AF detected by ELR and cardiologist verified 32 25 57 (4.0%) No AF detected by ELR 6 1,349 1,355 T

• tal

38 (2.7%) 1,374 1,412

Results

Sensitivity: 84.2% Specificity: 98.2% PPV: 56.1% P-value=<0.001

AF detected by ELR, rejected by Holter

AF in Holter not automatically detected by ELR

Conclusions

• Automatic ELR detection of AF results in an AF-diagnosis in more than

5 patients without AF for each patient with Holter-verified AF

• Even after expert adjudication, sensitivity and positive predictive value
• f AF in ELR are modest to poor
• False positive identification of AF potentially leads to overuse of OAC

with increased risk of bleeding and of no benefit to the patient

Perspectives

• Automatic ELR is not suitable for screening stroke patients for AF
• This study calls for meticulous testing of new devices' ability to

diagnose AF before they are taken into use

Funding

• Regional Hospital of Western Jutland
• Health Research Fund of Central Denmark Region
• Danish Heart Foundation
• Aase and Ejner Danielsen Foundation
• Fam. Hede Nielsen Foundation
• Cabinetmaker Sophus Jacobsen and wife Foundation
• Aarhus University Travel Grant
• European Stroke Conference 2016 Travel Grant
• Danish Heart Foundation Travel Grant

Thank you for your attention