Modified positioning of a smartphone based single-lead electrocardiogram device improves detection of atrial flutter

Introduction: The AliveCor Kardia Mobile (AKM) is a handheld, smartphone based cardiac rhythm monitor that records a lead-I electrocardiogram (ECG). Despite being efficacious for detection of atrial fibrillation (AF), it is unclear whether atrial flutter (AFL) may be misdiagnosed as sinus rhythm due to regular R-R intervals. We hypothesised that generating lead-II tracings through repositioning of the AKM may improve visualisation of flutter waves and clinician diagnosis of AFL compared to traditional lead-I tracings.

Materials and methods: A prospective, multi-centre, validation study was conducted comparing standard lead-I AKM positioning with lead-II in AFL. A mixed cohort of lead I tracings from patients in AF and sinus rhythm were also included. Two independent electrophysiologists (EP) analysed all ECGs blinded to the automated device diagnosis.

Results: Fifty patients were recruited, 11 in atrial flutter, 14 in atrial fibrillation, and 25 in sinus rhythm. Lead-I AFL sensitivity was 27.3% for both EP's which individually improved to 72.7% and 54.6% in lead-II. AKM appropriately diagnosed lead-I AFL as unclassified in 18.2% of cases, compared to 54.5% in lead-II. Overall clinician agreement (AF, SR and AFL) was modest utilising AFL lead-I (EP1: κ = 0.71, EP2: κ = 0.73, p < 0.001), which improved with lead-II tracings (EP1: κ = 0.87, EP2: κ = 0.83, both p < 0.001).

Conclusion: Repositioning of the AKM device improves clinician diagnosis of atrial flutter. A lead-II tracing may be considered in high-risk patients to improve detection of atrial flutter.