Non-Invasive Localization of Cardiac Isochrones using the standard 12 lead ECG using the cardiac isochrone positioning system

Background: The precise localization of the site of origin of a premature ventricular contraction (PVC) prior to ablation can facilitate the planning and execution of the electrophysiological procedure. In clinical practice the targeted ablation site is estimated from the standard 12 lead ECG. The accuracy of this qualitative estimation has limitations, particularly the localization of PVCs originating from the papillary muscles frequently fails. Electrocardiographic imaging (ECGI) techniques might support the localization of these PVCs, as the cardiac anatomy is taken into account. Many of the current available ECGI methods do require body surface maps, and can localize the PVC origin only the epicardium of the heart. The purpose of this presentation is to demonstrate that the Cardiac Isochrone Positioning System (CIPS) program can detect accurately the location of PVC specifically, even on the papillary muscle using only a 12-lead ECG.

Methods: CIPS uses three components: 1) endocardial and epicardial cardiac anatomy and torso geometry are derived from MRI, 2) the patient specific electrode positions are derived from a registered 3D image and 3) the 12 lead ECG. CIPS localizes the PVC origin by matching the anatomical isochrone vector with the ECG vector. The predicted PVC origin was compared to the site of successful ablation or stimulation.

Results.  Three patients that underwent electrophysiological mapping and ablation of PVCs at the papillary muscles were studied. CIPS localized the PVC origin for all patients to the correct region, including papillary muscle.

Conclusions. This study of this novel vector-based ECGI method using only the standard 12-lead ECG shows promise to localize the origin of PVC accurately, also to specific sites like the papillary muscles. 

Peter van Dam has a faculty position in the UCLA (Los Angeles, US) and has his own company Peacs BV, specialized in academic cardiac software for research and education (www.ecgsim.org and www.circadapt.org). His research interest are in bridging the gap between cardiac modeling and the clinical use of these models. He received his PhD in 2010 The shortest path to cardiac activation. Supervisor: Adriaan van Oosterom, Radboud University, Nijmegen, the Netherlands.