Some Effects of the Intravenous Administration of Calcium in Man

Summary Calcium was administered by intravenous infusion or injection into 19 subjects, in doses ranging from 180 to 864 mg. The effects observed were bradycardia and sinus arrhythmia, an increased pulse pressure, shortening of theQ‐Tcinterval with depression and inversion ofTwaves, and an increase in gastric secretion. Atropine prevented the development of the bradycardia, sinus arrhythmia and the increase in gastric secretion, but did not prevent the increase in pulse pressure. None of the changes occurring ran parallel with the serum calcium levels, and with the exception of theT‐wave changes, which persisted after the serum calcium levels had returned to normal, they appeared to be related to the acute rise in serum calcium levels.