Effect of lateral body position on transesophageal echocardiography images and the association with patient characteristics: A prospective observational study

BACKGROUND: Changes in heart position are occasionally observed on the transesophageal echocardiography (TEE) image screen after changing the body position from supine to lateral, although the magnitude of change in cardiac position varies individually. We hypothesized that this variation is associated with certain patient characteristics and evaluated how lateral positioning affects visualization of the heart on TEE and whether the magnitude of change in the heart position correlates with patient characteristics. METHODS: Fifty-three lung resection patients were enrolled. Two angle and two length parameters (Δθ(TV), Δθ(AP), ΔL(TV), and ΔL(AP)) were defined to describe location change of the lateral tricuspid annulus and right ventricular apex on the TEE image between supine and lateral position. The correlation coefficients were calculated between these four parameters and patient characteristics, including age, body mass index (BMI), epicardial fat thickness, and pulmonary function variables. RESULTS: The Δθ(TV) correlated positively and inversely with BMI in both right and left lateral patients (right: r = 0.6365, P = 0.0034; left: r = −0.6616, P < 0.0001, respectively). In left lateral patients, the Δθ(TV) correlated inversely with epicardial fat thickness (r = −0.4879, P = 0.0182), and the ΔL(AP) correlated positively with the forced vital capacity percent predicted (r = 0.5736, P = 0.0082). CONCLUSIONS: Lateral body positioning affects cardiac visualization on TEE, and the BMI, epicardial fat thickness, and pulmonary function moderate this effect.