sˌʌm sˈoːɹsᵻz sˈaɪt ðætðə pˈɛktᵻnˌeɪt mˈʌsəlz ɑːɹ jˈuːsfəl ɪn ɪŋkɹˈiːsɪŋ ðə pˈaʊɚɹ ʌv kəntɹˈækʃən wɪðˌaʊt ɪŋkɹˈiːsɪŋ hˈɑːɹt mˈæs səbstˈænʃəli.
Some sources cite that the pectinate muscles are useful in increasing the power of contraction without increasing heart mass substantially.