Mitral prolapse is a common condition, defined by the systolic bulging of at least one mitral leaflet into the left atrium, which is often accompanied by various degree of mitral insufficiency. While for most of the patients the prognosis is linked to the severity of the valve regurgitation and its repercussions on the left ventricle (dilation and/or dysfunction), a minority of patients present with severe ventricular arrhythmia and an increased risk of sudden cardiac death, irrespective of the severity of the mitral regurgitation. To describe this particular condition, the terms arrhythmic or malignant mitral valve prolapse have been coined. The aim of this article is to describe the clinical, electrocardiographic and morphologic characteristics, which have been associated with an increased risk of arrhythmia in patients with mitral prolapse.