Palpitations are like headaches. By themselves they mean nothing. In rare instances a headache could be a brain tumor. A palpitation could mean anything. Sometimes it's something serious. If it is a rare occurance it probably is nothing. If it happens a lot, it is probably something, but the overwhelming odds are that something is far, far, far less sinister a medical condition than heart failure. I've had odd heart rhythm symptoms and some lightheadedness throughout my lifetime and I've had many tests. There are some mild abnormalities and such, but I don't have heart failure and I don't have any life altering heart disease. If you are ready to know this I'd encourage you to visit a cardiologist and get some tests. An echo looks at structural stuff, EKG's electrical integrity, and a stress test the heart when performing. If the results are normal or inconclusive you're pretty much fine. Anything really serious will show itself quite prominently within the results.
There are doctors forums where you can ask an expert your question. If you go to the top where it says forums pick Doctors Forums. This forum is generally attended by patients only. You should also probably seek out a doctor in your area to go see to be evaluated in person. That said, palpitations don't necessarily mean anything. the heart has to be evaluated to know exactly what it is you are feeling and if what you are feeling is dangerous to your heart. When you say it stops does it stop only for a quick beat or for longer. If it stops longer than a quick beat you should be evaluated to make sure you don't have any blocks but just because you have palpitations and possible heart block it doesn't mean you are in heart failure or will have heart failure. So my best advice is to see out a doctor in your area and just go and get a check up. There is no way for us to truly know without a doctor looking at us. Take care and keep us posted on how you are.