The isolated perfused heart preparation: two suggested improvements

A new method of recording the contractions of the isolated perfused heart is described. By “transverse” recording, a signal of simple waveform is obtained from the right ventricle at constant diastolic tension. Changes in heart rate and force of contraction of the rat isolated perfused heart caused by (‐)‐noradrenaline were measured. Of the three methods of assessing the response: (1) the increment as a percentage of the control record, (2) the increment in absolute units and (3) the increment as a percentage of the maximum, the latter has most pharmacological meaning.