these conditions are treated by the drug eucardic and are linked to hypertension. See www
www.nlm.nih.gov/medlineplus/arrhythmia.html -
or www.medicinenet.com/arrhythmia_irregular.../article.htm - or
en.wikipedia.org/wiki/Cardiac_dysrhythmia -

As you knew before posting your question, the prefix "eu-" is widely applied in Spanish, apparently to save typing. In this case I wanted to be sure though that the term applied directly to the heart _rate_, since the problem with condensing terms to this degree is that it really only tells you "normal heart".

I find several uses of "eucárdico" that directly contrast it to bradycardia (slowe rate) and tachycardia (fast rate) or that specify the actual (normal) heart rate. Most of these are in Portuguese.

For example:
"Frequência cardíaca. Bradicárdico. Eucárdico. Taquicárdico. Em branco ..."

"Eucárdico Bradicárdico Taquicárdico. Normotenso Hipotenso. Hipertenso. Pulso..."

"Pulso cheio, arrítmico e eucárdico (Pulso = 60bpm), Freqüência Cardíaca = 60bpm. Perfusão capilar diminuída +1/+4. AGI: RHA aumentados."

(Note: 60 bpm is still within normal)

I am having trouble posting the links though (almost all for Pdf files). Most are on the second page of my Google hits for eucárdico

Note: I live in Paraguay, and Brazilian terms have been creeping in here (although this isn't an entirely normal term). I would love to know what country your text comes from if possible.