Palpitations are extremely common. A palpitation is simply an abnormal sensation of the heart beating. Most people who complain of palpitations describe them either as "skips" in the heartbeat or as periods of fast and irregular heartbeats.
Most people with palpitations have some type of cardiac arrhythmia. Any arrhythmia can cause palpitations, but the most common causes of palpitations are atrial or ventricular extra beats, episodes of atrial fibrillation(AF) or supra-ventricular tachycardia (SVT).
Unfortunately, on occasion palpitations can be a manifestation of a more dangerous heart arrhythmia, such as ventricular tachycardia which may cause cardiac arrest and sudden death. If you are having troublesome palpitations then it is important to seek medical advice.
AF can present as palpitations but is sometimes entirely asymptomatic. It is an important arrhythmia to detect as it is associated with an increased risk of stroke.