Risk of infective endocarditis in mitral valve prolapse with and without precordial systolic murmurs
MacMahon SW., Hickey AJ., Wilcken DEL., Wittes JT., Feneley MP., Hickie JB.
The risk of infective endocarditis (IE) associated with a systolic murmur in patients with mitral valve prolapse (MVP) was investigated in a case-control study. The case group comprised all patients with MVP (n = 19) from a series of 136 consecutive adult admissions for IE. Three matched control subjects were chosen for each case from a series of 144 MVP patients without IE. Seventeen of the 19 cases (89%) had documented evidence of systolic murmurs existing before the IE episode; systolic murmurs were documented in 25 of the 57 control subjects (47%). The data indicate a significant increase in the risk of IE in MVP patients with a systolic murmur (p <0.01). The absolute probability of IE developing in a patient with MVP and a murmur was estimated to be approximately 1 in 1,400 per year; this was 35 times greater than the probability in a patient with MVP without a murmur. The results suggest that by restricting prophylaxis to MVP patients with a systolic murmur, cover would be provided for almost 90% of those with MVP in whom IE would be likely to develop. © 1987 The Cahners Publishing Company, a Division of Reed Publishing USA, 249 West 17th Street, New York, New York 10011.