E.C.G. findings in normal rats and after administration of isoproterenol.

Electrocardiograms of normal rats were studied and compared with those of the rats receiving parenteral IPT. The rat E.C.G. resembles essentially human E.C.G. IPT administration brought about E.C.G. changes suggesting myocardial infarction. Appearance of Q wave in aVL was a consistent feature of E.C.G. after 24 hr of IPT injection. With additional doses of IPT the ECG in these rats showed a well marked Q wave and increase in the amplitudes of R and T waves in limb and increase in the amplitudes of R and T waves in limb and chest leads.