An experimental model to correlate simultaneous body surface and epicardial electropotential recordings in vivo

Our aim was to simultaneously record dense arrays of electropotential signals from the heart and body surface of a closed-chest anaesthetised pig during an acute period of regional ventricular ischaemia. After fitting a suture snare to the equatorial region of the left anterior descending (LAD) coronary artery, an electrode sock containing 127 stainless steel contact electrodes (spaced approximately 7 mm apart) was positioned over the ventricular epicardium. The chest was re-closed and fitted an elasticated vest containing 256 ECG electrodes (spaced approximately 15 mm apart). Electrode locations were measured using a mechanical digitising arm and projected onto a customised 3D mathematical model of the porcine torso and heart. Finite element fitted body surface potential maps (BSPMs) and epicardial activation sequences were used to interpret the electropotential signals. Data were sampled at 2 kHz and recorded at 20 s intervals during a four minute period of LAD occlusion, followed by a period of reperfusion and recovery. During occlusion, propagation of epicardial activation slowed monotonically across the ischaemic region and this was clearly associated with a zone of ST segment elevation in the BSPM and Lead V1 ECG, whilst the Lead II ECG remained relatively unchanged. The epicardial activation sequence had largely recovered after 60 s of reperfusion, although there was still evidence of slowed activation across the ischaemic region compared to the control. Electrocardiac activity had fully restored to its control state after six minutes of reperfusion. Simultaneous recordings of this type will provide an experimental model to be used together with our integrated computational framework to assess the accuracy and sensitivity of activation inverse ECG algorithms during normal and patho-physiological states. © 2002 Elsevier Science Ltd. All rights reserved.