In-vivo evaluation of reduced-lead-systems in noninvasive reconstruction and localization of cardiac electrical activity

Noninvasive imaging of electrical activity of the heart has increasingly gained attention last decades. Heart-surface potentials are reconstructed from a torso-heart geometry and body-surface potentials recorded from tens to hundreds of body-surface electrodes. However, it remains an open question how many electrodes are needed to accurately reconstruct heart-surface potentials. In a canine model, we reconstructed epicardial electrograms and activation locations, investigating the use of a full-lead system, consisting of 169 well connected body-surface electrodes, and reduced-lead systems: using half or a third of the electrodes, or a minimalistic set of the default 12-lead ECG. Correlation coefficients indicate that the quality of the reconstructed electrograms remains stable to a third of the electrodes, and decreases with fewer electrodes. Similarly, the mismatch between the detected origin of a beat and known pacing location decreases when fewer body-surface electrodes are used. However, when only 9 or 10 electrodes are available for pacing localization, the median mismatch is 30mm, only marginally higher than when half of the electrodes are used, although with a significant error spread up to 65mm. These results indicate that for specific purposes (such as detecting the origin of an extrasystolic beat), a lower number of body-surface electrodes can provide noninvasive electrocardiographic imaging results that might still be useful for a clinical purpose.