The purpose of this study, was to ascertain whether delayed sternal closure (DSC) could eliminate the need for an intra-aortic balloon pump (IABP) or ventricular assist device (VAD) in patients with low cardiac output syndrome (LCOS) following coronary artery bypass grafting surgery (CABG). To investigate this, the records of 3014 patients undergoing CABG were retrospectively reviewed. Sixty (2.0%) patients had a relative or absolute contraindication to IABP or VAD use and required DSC for LCOS. DSC resolved 45 (75%) of these patients' LCOS, requiring an average of 1.6 +/- 0.7 days and producing a mean change in cardiac index of +1.0 +/- 0.3 L/min/m2. Fifteen (25%) of these patients did not resolve their LCOS after DSC and required either an IABP (11) or a VAD (4). Significant postoperative morbidity occurred in 22 (36.7%) patients but were not related to DSC. Only one (1.7%) sternal wound infection occurred from a total of 147 patient-days of DSC. Operative mortality was 47 per cent (28) but was not unexpected based on the number of urgent/emergent (48; 80%) and reoperative (40; 67%) procedures but does not appear to be related to the technique of DSC. DSC appears to be a simple and safe method for treating LCOS following CABG. It is effective in resolving the majority of patients' LCOS without the addition of any significant morbidity. DSC also spares these patients the added morbidity, mortality, and cost associated with circulatory assist devices.