Objective: Partial left ventriculectomy (PLV), pioneered by Batista, has been proposed as an alternative treatment strategy in patients with refractory congestive heart failure. In order to analyze the midterm outcome of PLV and mitral valve (MV) repair and stratify patients according to risk, we prospectively studied 57 consecutive patients who underwent this procedure at the Cleveland Clinic Foundation (CCF). Methods: Patients had a mean age of 53 years and were predominantly males (74%). In 95% the etiology of heart failure was idiopathic dilated cardiomyopathy. All patients had a left ventricular end diastolic diameter of >7cm and were in New York Heart Association (NYHA) functional classes III and IV. A total of 54 patients (95%) were awaiting heart transplantation. Preoperatively, requirements included inotropes in 23 (40%), intraaortic balloon pump counterpulsation in 3 (5.3%), and left ventricular assist device placement (LVAD) in 1 (1.8%). Concomitant procedures included MV repair (55 patients), MV replacement (2), tricuspid valve repair (34 patients), coronary artery bypass graft (CABG) (5), and aortic valve repair or replacement (1 patient each). Results: Measurements preoperatively and at 3 months demonstrated improvement in left ventricular ejection fraction (14.4±7.7–23.2±10.7%, P<0.001), left ventricular end diastolic volume (254±85–179±73 ml, P<0.001) and left ventricular end diastolic diameter (8.4±1.1–6.3±0.9 cm, P<0.001). Peak oxygen consumption (MVO2) increased from 10.6±3.9 to 15.3±4.5 ml/kg per min (P<0.001). Cardiac index did not change (2.2 l/min per m2), although 40% had been on inotropes preoperatively and none were on inotropes at 3 months. NYHA functional class improved from 3.6±0.5 preoperatively to 2.2±0.9 at 3 months (P<0.001). LVAD support was required as rescue therapy in 11 patients (17%). Actuarial freedom from procedure failure, defined as death or relisting for transplant, was 58% at 1 year. Hospital mortality was 3.5% (n=2). On follow-up, there were 7 late deaths (including 3 sudden deaths) giving an actuarial survival of 82% at 1 year. Multivariate risk factor analysis revealed that age less than 40 years was associated with failure (P=0.02). Conclusions: Although PLV with MV repair is now a surgical option in the treatment of end-stage congestive heart failure, caution is advised as early failures are unpredictable and mechanical support may be required as rescue therapy. Better risk stratification and patient selection may improve outcome. Further study is required to determine the procedure's exact role in the treatment of congestive heart failure.