Performance of Single-Lead Handheld Electrocardiograms for Atrial Fibrillation Screening in Primary Care: The VITAL-AF Trial.

Background: Handheld single-lead electrocardiographic (1L ECG) devices are increasingly used for atrial fibrillation (AF) screening, but their real-world performance is not well understood.
Objectives: The purpose of this study was to quantify the diagnostic test characteristics of 1L ECG automated interpretations for prospective AF screening.
Methods: We calculated the diagnostic test characteristics of the AliveCor KardiaMobile 1L ECG (AliveCor, US) algorithm using unblinded cardiologist overread as the gold standard using single 30s tracings administered by medical assistants among individuals aged ≥65 years participating in the VITAL-AF trial (NCT03515057) of population-based AF screening embedded within routine primary care.
Results: A total of 14,230 individuals (mean age 74 ± 7 years, 60% women, 82% White) had 31,376 tracings reviewed by 13 cardiologists. A total of 24,906 (79.6%) tracings had an AliveCor interpretation of normal , 5,046 (16.1%) were unclassified , 797 (2.5%) were possible AF , and 573 (1.8%) were no analysis . Cardiologists read 808 (2.6%) tracings as AF. AliveCor possible AF had a PPV of 51.7% (95% CI: 47.8%-55.6%). AliveCor normal had an NPV of 99.8% (95% CI: 99.7%-99.8%). The AliveCor algorithm had an overall sensitivity of 51.0% (95% CI: 47.1%-54.9%) and a specificity of 98.7% (95% CI: 98.6%-98.9%). AliveCor tracings interpreted as unclassified (PPV 5.9%, 95% CI: 5.1%-6.7%) and no analysis (PPV 6.5%, 95% CI: 4.6%-8.9%) had low predictive values for AF and were increasingly prevalent at older ages (13.7% for age 65-69 years to 28.1% for age ≥85 years, P  < 0.01).
Conclusions: In an older primary care population undergoing AF screening with handheld 1L ECGs, automated algorithm interpretations were sufficiently accurate to exclude the presence of AF but not to establish an AF diagnosis.
Competing Interests: Dr Ellinor is supported by grants from the 10.13039/100000002National Institutes of Health (1RO1HL092577, 1R01HL157635, 1R01HL157635); by a grant from the 10.13039/100000968American Heart Association Strategically Focused Research Networks (18SFRN34110082); and by a grant from the European Union (MAESTRIA 965286). Dr Singer is supported, in part, by the Eliot B. and Edith C. Shoolman Fund of Massachusetts General Hospital. This study was investigator-initiated and funded by the Bristol-Myers Squibb-Pfizer Alliance. Dr Ellinor has received sponsored research support from Bayer AG and IBM Research; and has served on advisory boards or consulted for Bayer AG, MyoKardia, and Novartis. Dr Atlas has received sponsored research support from Bristol-Myers Squibb-Pfizer; has received sponsored research funding from Bristol Myers Squibb-Pfizer; and has consulted for Boehringer Ingelheim, Bristol Myers Squibb, Pfizer, and Fitbit. Dr Lubitz is an employee of Novartis Institutes for BioMedical Research. Dr Singer has received research support from Bristol Myers Squibb-Pfizer; and has received consulting fees from Bristol Myers Squibb-Pfizer, Fitbit, and Google. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(© 2023 The Authors.)