Overview of Mitral Prolapse
Traditionally it was thought that MVP occurred in ~ 5% of the general population, however an offshoot of the Framingham study, which examined over 1800 echocardiograms, placed the incidence at 2.4% and noted that the difference in men and women was significant (59% of them occurred in women) [Freed LA et al. NEJM 341: 1, 1997].
MVP is almost always asymptomatic, thus it is generally diagnosed when a midsystolic click is noticed (and confirmed with echocardiography). MVP is usually caused by redundant tissue or myxomatous degeneration of valve leaflets and the posterior leaflet is more commonly affected than the anterior. 15% of these patients have a component of mitral regurgitation.
Symptoms, which are rare, include chest pain, mitral regurgitation (15%), atrial and ventricular arrhythmias, embolic events, and infective endocarditis. Sudden death is extremely rare. The prolapse can be accentuated by decreases in preload. Some patients show inverted or biphasic T waves or ST-segment changes inferiorly on EKG. These patients also have an increased incidence of abnormal AV bypass tracts.
Effect on cardiac anatomy
15% will have mitral regurgitation. Increased incidence of abnormal AV bypass tracts
If asymptomatic, does not require any special anesthetic regimen. The key to anesthesia in MVP is minimizing excessive LV contraction (e.g., SNS stimulation, decreased SVR, hypovolemia, or unusual surgical positioning). Keep in mind, however, that these patients are at increased risk for intraoperative arrhythmias – these can be prevented with relatively deep volatile anesthesia, and if they do occur, normally respond to lidocaine. Hypovolemia should be avoided as it worsens the prolapse.