Left atrial functional remodeling after heart transplantation: longitudinal comparison of bicaval and biatrial techniques

Background Surgical implantation technique during heart transplantation influences atrial anatomy and function. However, longitudinal data on left atrial functional remodeling comparing bicaval and biatrial techniques remain limited. Methods Adult heart transplant recipients undergoing standardized echocardiographic follow-up were retrospectively analyzed. Of 162 screened patients, 50 (25 bicaval, 25 biatrial) met predefined inclusion criteria and completed serial assessments at 3, 6, 9, and 12 months after transplantation. Left atrial reservoir strain (LASr) and conduit strain (LAScd) were assessed using speckle-tracking echocardiography. Longitudinal changes were compared between surgical techniques. Results At 3 months, LASr and LAScd were comparable between groups. During follow-up, reservoir function improved progressively in bicaval recipients but remained attenuated in biatrial recipients. LASr was significantly higher in the bicaval group at 6, 9, and 12 months (all p < 0.01). Similarly, LAScd was significantly more negative in bicaval recipients from 6 months onward (p = 0.002 at 6 months; p < 0.001 thereafter), indicating superior conduit function after bicaval heart transplantation. Differences between techniques became more pronounced over time. Conclusion Left atrial functional remodeling after heart transplantation differs according to surgical implantation technique. Bicaval transplantation is associated with superior longitudinal recovery of left atrial reservoir and conduit function compared with the biatrial technique. These findings suggest more favorable atrial–ventricular coupling during graft adaptation and may have implications for post-transplant diastolic performance.