Influence of Electrode Placement on the Morphology of In Silico 12 Lead Electrocardiograms

Introduction: Multiple clinical studies have aimed to assess the influence of electrode placement on 12 lead electrocardiogram (ECG) morphology. However, a study has not yet been conducted in silico. We therefore aim to systemically investigate the influence of electrode positioning on the morphology of the 12 lead ECG using a cardiac model of electrophysiology under both healthy sinus rhythm and right bundle branch block (RBBB). Methods: A biophysically-detailed model of ventricular electrophysiology of a single subject was used to model body surface potential maps during healthy sinus rhythm and RBBB. A systematic automatic perturbation of all electrodes from the original subject configuration was performed to replicate clinical variation. For each variation in electrode placement, the 12 lead ECG was computed under both conditions. Quantitative differences were assessed using a time-averaged normalized $L_{2}$ norm. Results: The precordial leads that lie in closer proximity to the heart, primarily V2 and V3, experienced the largest morphological changes from vertical electrode movement. Morphological variation in the augmented Goldberger and Einthoven leads resulted predominantly from LA electrode placement. The possibility of a false diagnosis of RBBB during sinus rhythm due to improper electrode placement was also demonstrated.