Why could the heart flutter at night?

Rhythm problem: Palpitations or fluttering sensations in the chest most commonly mean that the heart is actually beating irregular with some early beats and some pauses. This can occur at any time of day but not uncommonly, the patient is more likely to notice the sensations at night when lying still or on the left side. Also, in some cases the skipping is more likely to occur when the pulse is slower(lying down).

Hard to say: This could be secondary to being aware of heart beating because it is quiet or due to extra heart beats which are for the most part benign. Other causes include fast regular and fast irregular heart rhythms, your doctor and a holter monitor can help with the correct diagnosis.

Heart flutter: The likely reason that your heart flutters at night is that as you are falling asleep you are most aware of your heartbeat, so you feel it more. There is little noise or sounds to distract you.