When the heart literally quivers we refer to it as fibrillation and it is not compatible with life so I suspect that it feels as if your heart is quivering when it fact it is simply beating in a different manner. Heart beats vary quite a bit and we usually ignore their differences. Think about how much you screen out daily. Young folks text mesage, listen to music, fiddle with their laptop, and play games all at the same time! You ignore most of what is going on - and something has you paying more attention to your heartbeats - so deal with that first.
seeing your wife without makeup for the first time! Gottttttt--Dammmmmnn! When my wife walks around the house with out makeup , it instantly becomes haunted! A good buddy of mine once told me " That be-itch could haunt a house!"
This can be an arrythmia (irregular heartbeat) of your heart. This can be a lifethreatening situation and you should seek medical treatment immediately! Go to an Emergency Room now! Do NOT wait!
Do you have any other symptoms? You may have palpitations, murmurs or arrhythmia. Most murmurs are pretty innocuous (though some can be serious) and palpitations are normally pretty benign, but arrhythmia can be fatal, so you should get to your doctor.
many factors.. from diet.. high cholesterol.. enlarged heart.. mumurs.. blood pressure being too high or too low... other diseases.. forms of angina...
see the doctor... since this is a problem... and there's many causes for it... it's best to have the doctor check it out.. take your blood and get a scan... to see if there's something internal that's happening or your diet is a problem.