Palpitations, or an awareness of the heart beat, can be an unpleasant sensation and can indicate an important underlying problem. The heart beat may become irregular or beat too slow or fast and may be associated with other symptoms such as breathlessness, ‘giddiness’ feeling faint and transient loss of consciousness. Over exertion, anxiety or the excessive use of stimulants (caffeine, alcohol and nicotine) may be a cause. When a single heart beat occurs earlier than normal, it is called a premature contraction and this can cause the sensation of a forceful heart beat. Abnormal electrical activity affecting the heart’s natural pacemaker and conduction fibres will need more careful evaluation before the correct treatment can be advised.