Although the systolic click was first mentioned in the medical literature in 1887, it was not until the investigations of John Barlow and his colleagues in the 1960s that it became linked to the mitral valve and mitral valve prolapse identified as the cause. Mitral valve prolapse is currently the most commonly diagnosed cardiac valvular abnormality. Significant complications may occur with mitral valve prolapse, though most patients are asymptomatic. However, a number of issues persist regarding mitral valve prolapse, especially with respect to the mitral valve prolapse syndrome, a term which has been applied to patients who develop a variety of symptoms, including chest pain, shortness of breath, fatigue, lightheadedness, syncope, palpitations, anxiety, and panic attacks.