My heart flew up into my mouth when I saw the risk that the child was taking.

You might say, for example, that your heart was in your mouth when you asked a bank to lend you some money to pay for a new house.

The paupers told me that they always gorged to the bursting point on Sundays, and went hungry six days of the week.

Millions of people watched the first moon landing on TV, their hearts in their mouths, aware of how difficult and dangerous an adventure was, and what risks had to be taken.

I don't know if I'm nervous or excited, but my heart is about to jump up my throat.