Influence of left ventricular function on development of systolic anterior motion after mitral valve repair

Objective: A hyperkinetic heart has been suggested as a risk factor for systolic anterior motion (SAM) after mitral valve repair, but the influence of preoperative left ventricular (LV) function on the development of SAM has not been elucidated. Methods: Transthoracic echocardiographic data were retrospectively reviewed in 441 patients who underwent mitral valve repair for degenerative mitral regurgitation. Comparisons were made between patients with and without SAM (SAM cases vs noncases). Results: The incidence of SAM was 6.1% (27/441). There were no differences in preoperative characteristics and operative procedures between the 2 groups except the prevalence of Barlow disease. The SAM cases exhibited a higher preoperative ejection fraction (EF) (SAM cases, 70.0% +/- 7.1%; noncases, 65.1% +/- 6.9%; P < .01) and smaller preoperative systolic LV end-systolic dimension (LVDs) (32.0 +/- 5.4 mm vs 35.4 +/- 5.7 mm; P = .02) than the noncases. The incidence of SAM was significantly associated with greater preoperative EF (P < .01 for trend) and reduced LVDs (P < .01 for trend). SAM did not occur in patients with an impaired (EF < 60%) or enlarged (LVDs > 45 mm) LV. The incidence of SAM was highest among patients with a small hyperkinetic heart. Conclusions: The study indicates that the development of SAM after mitral valve repair is associated with preoperative LV function. A small hyperkinetic heart is considered a risk factor for SAM and should be treated with caution.