Use of electromagnetic counterpoise to measure cardiac force.

To quantify the drug induced changes in cardiac force the methods in vogue use springs and strain-gauge coils, which apply counterforce to oppose cardiac force and thus stop systolic excursion of the lever. The present report pertains to a new technique based on similar principle, utilising induced electromagnetic force as a means of counterpoising in study of contractility of isolated, frog heart. The technique monitered changes in contractility produced by small doses of adrenaline, digoxin, acetylcholine and CaCl2. The plots of estimated cardiac force (in V) against doses (log-units) of the drugs could be made to reveal dose response relation.