why does my heart suddenly pound hard once and it makes it difficult to catch that one breath? Its been going on for a couple months now but i can just be at home watching tv and out of no where i feel my heart pound so hard that it keeps me from catching the breath i was just about to take. It feels like someone knocked the wind out of me. What can it be? I know when i was about 2 years old i had a heart murmer but was told that it went away and my last check up said everything was normal. Ive gone to the doctor once about this a couple months ago, and they said everything was fine. what can it be? why am i always fighting for that one breath? im a guy, and im not an any kinds of medications.