Functional Assessment of Donor and Recipient Left Atrium in Heart Transplant Patients Using Full‐Volume Three‐Dimensional Echocardiography

Background: Atrial function plays an important role in many cardiac conditions, how recipient and donor compartments of left atrium (LA) of transplanted hearts differentially contribute to overall LA function in transplanted hearts has not been described. We tested whether three-dimensional transthoracic echocardiography (3DE) could be used to calculate these compartment-specific atrial functions. Methods and Results: We analyzed 3DE images of 22 consecutive transplant patients who had diagnostic imaging quality (ages 59 ± 16 years) using TomTec Research Arena. The contour of the recipient and total LA were traced frame by frame, and the donor LA volume was calculated as the difference of the total LA volume minus the recipient LA volume. The LA ejection fractions of total LA, donor LA, and recipient LA were also calculated as (LA atrial end-diastolic volume − LA atrial end-systolic volume)/LA atrial end-diastolic volume of each compartment. Interobserver variability of LA volumes for the total, recipient, and donor compartments were 5.6 ± 2.4, 5.4 ± 2.0, and 9.3 ± 3.2 mL, respectively (n = 11). The donor LA ejection fraction was higher than that of recipient (41 ± 18% vs. 30 ± 14%, P = 0.013). When the patients were categorized as asymptomatic (New York Heart Association functional class [NYHA] functional class I) and symptomatic (NYHA functional class II–III), indexed donor LA atrial end-diastolic volume was significantly lower in asymptomatic patients as compared with symptomatic patients. Conclusions: Compartment-specific LA volumes can be calculated in orthotopic heart transplant patients using full-volume 3DE. Our findings may suggest that unique contribution of each LA compartment of transplanted hearts toward the symptoms of these patients.