extrasystole vs systole

extrasystole and systole both are nouns.

Word	Noun	Adjective	Verb	Adverb
extrasystole	Yes	No	No	No
systole	Yes	No	No	No

As nouns, systole is a hypernym of extrasystole; that is, systole is a word with a broader meaning than extrasystole:

extrasystole: a premature systole resulting in a momentary cardiac arrhythmia
systole: the contraction of the chambers of the heart (especially the ventricles) to drive blood into the aorta and pulmonary artery

extrasystole (noun)	systole (noun)
a premature systole resulting in a momentary cardiac arrhythmia	the contraction of the chambers of the heart (especially the ventricles) to drive blood into the aorta and pulmonary artery