Virtual Electrode Polarization (VEP) is an effect seen when an electrical field is applied across cardiac tissue. Large regions of positive and negative polarization manifest on the tissue surfaces, and sometimes within the depths of the heart. I’d link to the Wikipedia article on the term, but there is none. Perhaps I should write one.

Here are some recently-published articles on the subject:

• N.H. Kuijpers et al. found that tissue irregularity increased the number of virtual electrodes in simulation. Given that VEP appears strongly at tissue borders, this is not surprising. It’s good to see a methodic investigation on the subject, though.
• D.L. Beaudoin et al. investigated the arrhythmogenic effect of plunge recording electrodes in real cardiac tissue. They found that in some cases, the VEP caused by plunge electrodes could induce reentry. This encourages optical mapping studies of surface activity, and points to simulation as even more advantageous for studying electrical activity withinthe heart.
• Fujian Qu and others from the Efimov lab found that ascending ramp defibrillation waveforms produce more pronounced VEP, thereby more effectively eliminating reentry. I had the pleasure of meeting Fujian this past fall, during our lab’s Post-Katina stay at Washington University. This approach promises to decrease the necessary defibrillation energy, which implies less damage on the heart from defibrillation shocks.

There are some other articles in my queue, but they are from 2004 and earlier. I’ll post more as they roll in.