A modified Lewis ECG lead system for ambulatory monitoring of atrial arrhythmias.

When using a reduced ECG lead system with three leads or less, the analysis of atrial activity during arrhythmias can become problematic due to low signal amplitude and noise. Long ago, Sir Thomas Lewis proposed a lead system for atrial activity enhancement in which two electrodes are placed directly on the chest, however, these leads are sensitive to arm movement artifacts. In this study, a modified Lewis lead system is proposed that is better suited for ambulatory applications since the electrodes are placed in areas with less muscle