OBJECTIVES We sought to assess the incidence and determinants of sudden dea
th (SUD) in mitral regurgitation due to flail leaflet (MR-FL).
BACKGROUND Sudden death is a catastrophic complication of MR-FL. Its incide
nce and predictability are undefined.
METHODS The occurrence of SUD was analyzed in 348 patients (age 67 +/- 12 y
ears) with MR-FL diagnosed echocardiographically from 1980 through 1994.
RESULTS During a mean follow-up of 48 +/- 41 months, 99 deaths occurred und
er medical treatment. Sudden death occurred in 25 patients, three of whom w
ere resuscitated. The sudden death rates at five and 10 years were 8.6 +/-
2% and 18.8 +/- 4%, respectively, and the linearized rate was 1.8% per year
. By multivariate analysis, the independent baseline predictors of SUD were
New York Heart Association (NYHA) functional class (p = 0.006), ejection f
raction (p = 0.0001) and atrial fibrillation (p = 0.059). The yearly linear
ized rate of sudden death was 1% in patients in functional class I, 3.1% in
class II and 7.8% in classes III and IV. However, of 25 patients who had S
UD, at baseline, 10 (40%) were in functional class I, 9 (36%) were in class
II and only 6 (24%) in class III or IV. In five patients (20%), no evidenc
e of risk factors developed until SUD. In patients with an ejection fractio
n greater than or equal to 60% and sinus rhythm, the Linearized rate of SUD
was not different in functional classes I and II (0.8% per year). Surgical
correction of MR (n = 186) was independently associated with a reduced inc
idence of SUD (adjusted hazard ratio [95% confidence interval] 0.29 [0.11 t
o 0.72], p = 0.007).
CONCLUSIONS Sudden death is relatively common in patients with MR-FL who ar
e conservatively managed. Patients with severe symptoms, atrial fibrillatio
n and reduced systolic function are at higher risk, but notable rates of SU
D have been observed without these risk factors. Correction of MR appears t
o be associated with a reduced incidence of SUD, warranting early considera
tion of surgical repair. (C) 1999 by the American College of Cardiology.