Calcium‐ion movement and contractility in atrial strips of frog heart are not affected by low‐frequency‐modulated, 1 GHz electromagnetic radiation

Calcium efflux from electrically stimulated, 45Ca(2+)-preloaded atrial strips of the frog heart was measured from samples of the rinsing perfusate collected at 2-min intervals for 32 min in a continuous perfusion chamber. Contractile force was simultaneously monitored. The specimen chamber was located in a stripline apparatus in which the atrial strips were exposed for 32 min to constant (CW) or amplitude-modulated (AM), 1 GHz electromagnetic (EM) fields at specific absorption rates (SAR) ranging from 3.2 microW/kg to 1.6 W/kg. Amplitude modulation was either at 0.5 Hz, in synchrony with the electrical stimulus applied to the preparation, or at 16 Hz. Neither unmodulated nor 0.5 Hz or 16 Hz modulated 1 GHz waves affected the movement of calcium ions or the contractile force in isolated atrial strips of the frog heart.