Diagnostic Accuracy of a Smartphone-Operated, Single-Lead Electrocardiography Device for Detection of Rhythm and Conduction Abnormalities in Primary Care

Jelle C.L. Himmelreich, MD, MSc; Evert P.M. Karregat, MD, MSc; Wim A.M. Lucassen, MD, PhD; Henk C.P.M. van Weert, MD, PhD; Joris R. de Groot, MD, PhD; M. Louis Handoko, MD, PhD; Robin Nijveldt, MD, PhD; Ralf E. Harskamp, MD, PhD


Ann Fam Med. 2019;17(5):403-411. 

In This Article

Abstract and Introduction


Purpose: To validate a smartphone-operated, single-lead electrocardiography (1L-ECG) device (AliveCor KardiaMobile) with an integrated algorithm for atrial fibrillation (AF) against 12-lead ECG (12L-ECG) in a primary care population.

Methods: We recruited consecutive patients who underwent 12L-ECG for any nonacute indication. Patients held a smartphone with connected 1L-ECG while local personnel simultaneously performed 12L-ECG. All 1L-ECG recordings were assessed by blinded cardiologists as well as by the smartphone-integrated algorithm. The study cardiologists also assessed all 12L-recordings in random order as the reference standard. We determined the diagnostic accuracy of the 1L-ECG in detecting AF or atrial flutter (AFL) as well as any rhythm abnormality and any conduction abnormality with the simultaneously performed 12L-ECG as the reference standard.

Results: We included 214 patients from 10 Dutch general practices. Mean ± SD age was 64.1 ± 14.7 years, and 53.7% of the patients were male. The 12L-ECG diagnosed AF/AFL, any rhythm abnormality, and any conduction abnormality in 23, 44, and 28 patients, respectively. The 1L-ECG as assessed by cardiologists had a sensitivity and specificity for AF/AFL of 100% (95% CI, 85.2%-100%) and 100% (95% CI, 98.1%-100%). The AF detection algorithm had a sensitivity and specificity of 87.0% (95% CI, 66.4%-97.2%) and 97.9% (95% CI, 94.7%-99.4%). The 1L-ECG as assessed by cardiologists had a sensitivity and specificity for any rhythm abnormality of 90.9% (95% CI, 78.3%-97.5%) and 93.5% (95% CI, 88.7%-96.7%) and for any conduction abnormality of 46.4% (95% CI, 27.5%-66.1%) and 100% (95% CI, 98.0%-100%).

Conclusions: In a primary care population, a smartphone-operated, 1L-ECG device showed excellent diagnostic accuracy for AF/AFL and good diagnostic accuracy for other rhythm abnormalities. The 1L-ECG device was less sensitive for conduction abnormalities.


Patients frequently visit their primary care physician with symptoms that may be due to cardiac arrhythmias.[1] Manifestations include palpitations, light-headedness, and (near) fainting and account for 0.8% to 16% of symptoms that prompt patients to visit their primary care physician.[1,2] Some heart rhythm abnormalities, such as ectopic beats, are common electrocardiography (ECG) findings that generally do not require action.[3] Others, such as atrial fibrillation (AF) or atrial flutter (AFL), are present in approximately 2% to 3% of the population and warrant further work-up and management to reduce associated risks of stroke and heart failure.[4–6] When a cardiac arrhythmia is suspected in a symptomatic patient, resting 12-lead ECG (12L-ECG) should always be performed.[7] Unfortunately, in primary care, performing 12L-ECG can be cumbersome, particularly during house visits, and it is not available at every practice. As a result, only in approximately one-third of cases is ECG performed during a symptomatic period.[3]

The availability of an unobtrusive, handheld ECG device is likely to lower the logistical threshold for performing ECG and may therefore improve detection of relevant arrhythmias in primary care.[8] One such device, the KardiaMobile, is a smartphone-connected, single-lead ECG (1L-ECG) device.[9,10] Smartphone-operated ECG has been studied for screening purposes and has shown great promise.[11] A recent report issued by the United Kingdom's National Health Service expects the device to be highly cost saving in the context of primary care.[12]

To our knowledge, the KardiaMobile has not yet been validated against simultaneously performed 12L-ECG in a primary care population. We hypothesized that the information obtained with smartphone-operated 1L-ECG can be used to accurately detect AF/AFL and common ectopic beats. We therefore performed a multicenter validation study in primary care to assess the validity of 1L-ECG as an office/bedside tool for the detection of arrhythmias as well as rhythm and conduction abnormalities compared with simultaneously performed 12L-ECG as assessed by blinded cardiologists as the reference standard.