(one's) heart misses a beat
One feels a flutter in one's chest or stomach from fear, nervousness, or excitement. My heart missed a beat when I saw that the doctor was calling with the results from the test. I swear, my heart missed a beat the first time I saw my wife. My heart misses a beat every time I'm called into my boss's office.
one's heart misses a beat
and one's heart skips a beatFig. one's heart flutters or palpitates; one has a strong emotional reaction. Whenever I'm near you, my heart skips a beat. When the racehorse fell, my heart missed a beat.