This study analyzed early clinical results after stentless mitral valve (Quadrileaflet Mitral Valve (QMV)/Quattro) implantation. A total of 28 patients have received a Quattro valve since August 1997. Patient age was 69+/-8 years; the underlying disease was mitral incompetence (14) and stenosis (13). Preoperative New York Heart Association functional class was 3.2+/-0.4 and cardiac index was 1.8+/-0.6. Mean cross-clamp duration was 58+/-19 minutes. Twenty patients received a 28-mm prosthesis, and eight patients received a 30-mm prosthesis. Four patients had myocardial revascularization, two had tricuspid valve repair, and six had radiofrequency ablation therapy to restore sinus rhythm. Mortality (1) was nonvalve related. Reoperation was necessary in two patients for posterior paravalvular leakage (1) and for functional stenosis (1). Echocardiography showed satisfactory hemodynamic function. By stentless mitral valve implantation the annuloventricular continuity is preserved to stabilize left ventricular function. The Quattro valve resembles native mitral valve function and is well suited for mitral valve replacement.