Recording of chest leads via mobile ECG and quantitative correlation with Wilson leads in a patient with monomorphic PVCs

Abstract Introduction Mobile ECGs using handy smartphone-based devices such as the KardiaMobile (AliveCor) are increasingly used as diagnostic tool for arrhythmias. They can be especially useful in cases of non-permanent arrhythmia. However, they were designed to record limb leads and few experience exists with the recording of modified chest leads. However chest leads provide important diagnostic information in many forms of arrhythmias including premature ventricular contractions (PVCs). We hypothesized that chest lead recordings using the 6-lead enabled KardiaMobile 6L device in a novel way would closely resemble the Wilson chest leads. Methods A patient with monomorphic idiopathic PVCs was identified. A standard 12- lead ECG was then taken in a supine position, and the exact same electrode positions were then used to record a mobile ECG in the supine position in the following manner: right finger and left finger positioned at the right and left sensor of the KardiaMobile 6L device respectively; back sensor positioned on the chest wall at the former positions of the chest electrodes, in a sequential manner (figure 1). The QRS morphologies of the 12-lead ECG Wilson leads and the reconstructed chest-leads with the mobile device were then overlied using Adobe illustrator and photoshop. The 12-lead ECG was also compared to a second 12-lead ECG of the patient that had been taken on the day before. Results QRS-morphologies of the chest leads derived from the 12-lead ECG and mobile ECG device resembled closely considering both regularly conducted beats and PVCs (figure 2 left and middle ECGs). Transition scores (TZ) of the sinus beats (3,5) and the PVCs (4) were identical. Overlaying two representative QRS-complexes of leads V1-6 of the Wilson leads and the mobile tracings showed a mean correlation of 73% for sinus beats and 78% for PVCs. In comparison, correlation of the QRS-complexes between the two 12-lead ECGs taken on consecutive days was 60% and 68% respectively (figure 2 left and right ECGs). Conclusion QRS-morphologies of the chest-leads taken with the KardiaMobile closely resembled the Wilson leads of the 12-lead ECG, and correlated better than did another 12-lead ECG that was taken the day before. The techniques could be useful for self-recording of arrhythmias including PVCs by patients to guide clinical decision-making in cases where no 12-lead ECG can be achieved due to intermittent arrhythmia occurrence.