Heart palpitations are uncomfortable, but that's often all they are. They're not necessarily a sign of heart disease.
Sometimes, your heart will toss out an early beat, known as a premature contraction. The next beat is delayed, feeling like your heart has skipped a beat. In actuality, your heart is balancing out the premature contraction with a delayed beat, and will generally carry on without problems.
So how do you know when heart palpitations are a sign of heart disease? If the palpitations are continuous, say more than six heart palpitations in sixty seconds, or three palpitations in succession, this could be a warning sign. If you're lightheaded or short of breath, if you have pain in your chest or are losing consciousness, you could have a serious situation on your hands.
"Luckily, most people won’t need medicines to treat palpitations that aren’t due to heart disease or illnesses. Sometimes the reassurance that your heart is normal is enough to make the palpitations less scary and therefore less noticeable. Remember that even though it seems as if your heart is going haywire, it’s still pumping all the blood required by your brain and other vital organs."
http://www.familydoctormag.com/heart-and-brain/231-heart-palpitations-are-they-dangerous.html