Palpitations and flutters are some of the words that people use to describe an abnormal sensation of pounding in the chest. They almost always due to some disorder of the heart rhythm (arrhythmias). These arrhythmias can be entirely benign, or they may be a manifestation of underlying heart disease, such as diseases of the heart muscle (cardiomyopathies) the heart valves (valvulopathies) or the conducting tissue (arrhythmias). They should always be investigated to exclude these underlying conditions.