ObjectiveClinical significance of left ventricular (LV) rehabilitation for borderline left ventricular (LV) hypoplasia is controversial. This study aimed to review the surgical results of patients with borderline LV hypoplasia, and to evaluate the impact of the LV rehabilitation on outcomes. MethodsPatients diagnosed with borderline LV hypoplasia and surgically treated from 2018 to 2022 were included. Overall surgical outcomes were evaluated and the changes in LV volumes calculated using angiography and zlog-NT-proBNP levels were analyzed in patients who underwent LV rehabilitation. ResultsThirty-three patients were included. Sixteen patients underwent primary biventricular repair, three patients underwent primary single ventricle palliation, and the remaining 14 patients underwent LV rehabilitation, including nine bilateral pulmonary artery banding (PAB) and ductal stenting, four central PAB, and one ductal stenting. Among fourteen patients who received LV rehabilitation, one died, one underwent single ventricle palliation, one was waiting for further procedure, and 11 underwent biventricular repair. After biventricular repair, 2 patients died, and 1 patient developed hemodynamic failure. As a result, only 8 patients were alive and in good condition. In patients who underwent LV rehabilitation, LV end-diastolic/end-systolic volume index, and LV stroke volume index increased over time after LV rehabilitation (p=0.001, p=0.007, and p=0.009, respectively). The zlog-NT-proBNP levels were stable until biventricular repair, but significantly higher in patients who presented with hemodynamic failure following biventricular repair compared to patients who did not exhibit hemodynamic failure. ConclusionsIn patients with borderline left heart hypoplasia, LV rehabilitation procedure promoted an increase in LV volume and contributed to establishing a biventricular circulation. The short-term results of this strategy are satisfactory, but further studies are essential to determine the long-term outcomes.