Session S32.4

Multisite Field Potential Recordings and Analysis of the Impulse Propagation Pattern in Cardiac Cells Culture

S Jacquir*, S Binczak, M Rosse, D Vandroux,
P Athias, JM Bilbault

Université de Bourgogne
Dijon, France

Abnormal cell-cell coupling is associated with increased arrhythmic risk, but the detailed electrophysiological understanding of this arrhythmic propensity is still unclear. To provide further insights into the impulse propagation between cardiac myocytes, we performed multiparametric studies of excitation spread with cellular resolution in a confluent single continuous layer of cultured cardiomyocytes (CM), which beat spontaneously and synchronously. In a first set of experiments based on a simultaneous paired intracellular recordings of action potentials in two individual CM, we observed slight periodic spontaneous advances/delays in the time lag between impulses, suggesting natural fluctuations in cell coupling and/or in conduction pathway. To check this, a non-invasive technology allowing the synchronous multifocal field potential (FP) recordings has been used. This technology is based on 60 substrate-integrated microelectrode arrays (MEA; 8x8 matrix, 30 µm electrode diameter, 200 µm inter-electrode distance). A platform including an acquisition and a treatment system of FP data has been designed. The two-dimensional maps derived from these multisite FP recordings confirmed that action potential (AP) parameters (rate, duration, voltage change velocity) were homogenous throughout the recording area. Conversely, the sequential mappings of the delays of activation calculated from the multielectrode matrix revealed for the first time random and iterative cycle-to-cycle changes in the direction of excitation spread. We hypothesized that these local spontaneous variations in the cardiac impulse propagation pathways may be a safety process protecting against microscopically discontinuous conduction, and abnormality of this natural process could contribute to the genesis of some heart arrhythmias.

(Abstract Control Number: 196)