Mechanoelectrical feedback in cardiac myocytes from stretch-activated ion channels

Stretch-activated ion channels (SACS) in cardiac myocytes from neonatal rats were studied in cell-attached patches. Stretch of membrane patches by suction in the recording pipette caused the triggering of action potentials that were recorded as action currents (ACs). The significance of a temporal correlation between SAC open probability and ACs was tested using the Kolmogorov-Smirnov and Poisson distributions. It was shown that the 50-ms epoch immediately preceding the action current has unique kinetics and represented a peak in SAC open probability (p<0.001). Thus it appears that current from a small number of SAC´s injects sufficient charge (0.2 pC during 50 ms) to trigger action potentials in myocytes. These data strengthen the hypothesis that passive mechanical stretch of myocardium can be arrhythmogenic.