/ Thesaurus / H Synonyms of heart muscle Find synonyms for: Noun1. cardiac muscle, heart muscle, muscle, muscular tissueusage: the muscle tissue of the heart; adapted to continued rhythmic contractionWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: persevere Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language