heart muscle heart·muscle uncommon noun 1. the muscle tissue of the heart; adapted to continued rhythmic contraction Synonymscardiac muscleheart muscle Related words Broader terms muscle Narrower terms pacemakerpapillary muscleatrioventricular bundleatrioventricular nodemyocardiumPurkinje fiberPurkinje network Parts heart WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
