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

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.

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.

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).

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.