monocrotism

from The Century Dictionary.

• noun A condition in which there is but one pulse-beat for each contraction of the heart: the opposite of dicrotism.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Physiol.) That condition of the pulse in which the pulse curve or sphygmogram shows but a single crest, the dicrotic elevation entirely disappearing.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun physiology A condition in which the pulse curve or sphygmogram shows only a single crest, the dicrotic elevation entirely disappearing.