Her heart knocked as hard as a fist on a door.

Her heart knocked so hard she shook from its blows.

Skye's heart knocked against her chest as she felt the door give.

I felt my heart knock against my chest like it wanted to get out.

Her heart was knocking again as she saw him come down the stairs.

Her heart knocked against her ribs as she stood there, watching him and waiting.

But most hearts knocked at the sight of a policeman's star.

Her heart was knocking and she felt hot all over.

As we floated waiting in free fall, I sensed how both my hearts knocked.

My heart knocked inside me with such force that I worried he would be able to feel it striking his breast.