BACKGROUND: Left ventriculoplasty (LVP) and mitral valve plasty (MVP) are sometimes effective for patients with idiopathic dilated cardiomyopathy (DCM) who are not eligible for heart transplantation. Strict patient selection is warranted for these controversial procedures. METHODS AND RESULTS: The subjects were 18 patients with idiopathic DCM and mitral regurgitation who had not been indicated for heart transplantation due to either older age or patient refusal, and who underwent LVP and MVP. Their mean age was 57±14 years and 50% were dependent on catecholamine infusion. The preload recruitable stroke work (PRSW) relationship and its slope (Mw) were estimated by a single-beat technique using transthoracic echocardiography. There were one 30-day mortality and six (33%) hospital deaths due to heart failure. The one-year survival rate was 50%. Left ventricular end-diastolic dimension (LVDd) decreased from 77±11 to 68±11mm (p=0.001) whereas the ejection fraction did not change. Preoperative Mw was significantly higher in one-year survivors than that in non-survivors (54±17ergcm(-3)10(3) vs. 31±10ergcm(-3)10(3), p=0.005). Preoperative LVDd was not different between the groups. The cut-off value of 42ergcm(-3)10(3) for Mw predicted one-year survival with high sensitivity (100%) and specificity (77%). CONCLUSIONS: Mw, the slope in the PRSW relationship, may predict survival after LVP and MVP in patients with idiopathic DCM.