| Сердце Маши сильно забилось. | Masha's heart pounded. |
| Он не жалеет своё сердце. | He doesn't take care of his heart. |
NB When the word сердце functions as a subject and does not have a descriptive modifier, the construction сердце у + Genitive is often preferred to (a) and (b), above: | |
| Сердце у Маши сильно забилось. | Masha's heart pounded. |