Not predominantly in humans. Most human cardiac myocytes (also called cardiomyocytes) remain mononucleated throughout life; only a minority become multinucleated, usually with two nuclei.
Nuclearity varies by species. In many rodents and some other mammals, adult cardiomyocytes are predominantly binucleated, but that is not the usual pattern in humans and other primates, where single-nucleus cells predominate and DNA content (ploidy) often increases instead.