Never has an illusion of innocence been so thoroughly shattered as in the case of the late systolic murmur with a systolic click. Taught for years that this auscultatory finding is innocent, we would rarely inform the patient about it, and, if we did, we would hasten to reassure him, or more often her, about its lack of importance. A decided change in attitude occurred after Barlow et al1 (1963) and others had established the association of the murmur and click with idiopathic mitral valve prolapse (Barlow syndrome). Not only do we inform patients about this syndrome, but we also tell them of its implications, particularly of the need for antibiotic prophylaxis against bacterial endocarditis when dental extraction or other surgical procedures are contemplated.
It is now well recognized that idiopathic prolapse of the mitral valve is frequently associated with anxiety, chest pain, palpitations, dyspnea, lightheadedness, cardiac arrhythmias, electrocardiographic
Vaisrub S. Late Systolic Click Syndrome. JAMA. 1975;234(6):632. doi:10.1001/jama.1975.03260190060031