Inverse solution electrocardiographic mapping of epicardial pacing correlates with three-dimensional electroanatomic mapping

We hypothesized that the calculation of epicardial potentials from body-surface potential maps (BSPMs) could aid ablation of ventricular tachycardia (VT). BSPMs were recorded during epicardial catheter mapping and pacing in 2 patients. Single-beat epicardial maps were calculated by inverse solution using customized torso/cardiac geometry, discretized from a CT scan. During pacing from 48 epicardial sites, we observed stimulus-QRS delay (Stim-QRS) of 27 plusmn 7 ms and a difference between known pacing locations and calculated sites of earliest potential minima of 1.6 plusmn 1.4 cm. Pacing in scar and scar-border zones had longer Stim-QRS delay (51 plusmn 24 ms and 35 plusmn 23 ms, respectively, p=0.004), and greater distances between known pacing sites and known locations (3.0 plusmn 1.6 cm and 4.6 plusmn 2.0 cm, respectively, p=0.0004). BSPM with inverse solution mapping can identify sites of earliest epicardial activation and thus could have clinical utility.