Palpitation is an awareness of the abnormal beating of the heart. It may occur in people with or without heart problems. Heart palpitations when lying down is not a common occurrence and can be caused by various factors.
Flat feet occur when the normal foot arches have partially or completely collapsed. When the foot is put to the ground the inner or middle side of the foot comes down to the floor rather than remaining raised. This can cause the whole foot to roll inwards (this is called over-pronation).
Flat feet/fallen arches. Having flat feet is also known as having fallen arches, and means the arches of the feet are low or there are no arches. Flat feet may not cause any pain or problems, but strain can be caused to muscles and ligaments making it painful when walking.