Palpitation is a rapid, forceful, or
irregular beating of the heart. In most cases, it is caused by nervous preoccupation with one's own heart action, either from fear of heart disease or from emotional disorders.
Palpitation can also be a symptom of a number of organic diseases of the heart or other organs, such as the thyroid gland. Sinus
tachycardia is a disorder characterized by a heart rate of more than 100 per minute. It is generally acquired gradually.
Premature ventricular systole creates the false
sensation of the heart skipping a beat, because of premature
contraction of the heart ventricles after a previous contraction and a prolonged compensatory pause before the next regular contraction. Paroxysmal tachycardia is a rapid but regular heartbeat that causes a fluttering sensation in the chest. Paroxysmal atrial fibrillation is a rapid, irregular pounding caused by temporary loss of rhythm in the atria, or auricles, of the heart.