Comparison of Echocardiographic Parameters Between Left Lateral Decubitus Position and Supine Position

Background: Body position significantly influences cardiac hemodynamic and echocardiographic measurements. While transthoracic echocardiography (TTE) is routinely performed in the left lateral decubitus (LLD) position for optimal image quality, clinical scenarios often necessitate imaging in the supine position. Understanding positional variations in echocardiographic parameters is crucial for accurate diagnostic interpretation and patient management, particularly in intensive care settings where patient repositioning may be limited. Objective: This study aimed to systematically compare echocardiographic parameters obtained in supine and left lateral decubitus positions in healthy adults and determine the clinical significance of positional variations. Methods: A prospective cross-sectional observational study was conducted at Aarupadai Veedu Medical College and Hospital, Puducherry, involving 44 healthy adult participants (22 males, 22 females; age range 18-60 years). Comprehensive echocardiographic assessments were performed in both supine and LLD positions using standardized protocols following British Society of Echocardiography guidelines. Parameters evaluated included cardiac chamber dimensions, valvular velocities, stroke volume, cardiac output, and functional indices. Statistical analysis employed paired t-tests and Wilcoxon signed-rank tests with significance set at p<0.05. Results: Significant positional differences were observed in multiple echocardiographic parameters (p<0.05). The supine position yielded higher values for: mitral E-wave velocity, left atrium dimension (3.2±0.4 vs. 2.9±0.3 cm), left ventricular end-diastolic dimension (4.8±0.5 vs. 4.3±0.4 cm), left ventricular end-systolic dimension, stroke volume (71±8 vs. 64±7 mL), cardiac output (5.1±0.6 vs. 4.6±0.5 L/min), LVOT-VTI, and peak velocities across aortic, pulmonic, and tricuspid valves. Conversely, mitral A-wave velocity was higher in LLD position. No significant positional variations were detected in heart rate, aortic root dimension, LVOT diameter, interventricular septum thickness, left ventricular posterior wall thickness, ejection fraction, fractional shortening, or TAPSE (all p>0.05). Image quality was superior in LLD position (70% vs. 30%). Conclusion: Body position significantly influences several echocardiographic parameters, with the supine position generally yielding higher chamber dimensions and flow velocities compared to LLD. These findings underscore the importance of standardizing patient positioning during echocardiographic examinations and considering positional variations when interpreting serial studies performed in different positions. While LLD remains the preferred position for optimal image quality, understanding these variations enables more accurate clinical interpretation in situations where supine imaging is necessary.