Agreement Between Standard and Right Ventricular-Focused Apical Four-Chamber Views for Right Ventricular Longitudinal Functional Indices: A Within-Participant Agreement Study.

PURPOSE: To determine whether right ventricular (RV) longitudinal functional indices measured from standard and RV-focused apical four-chamber (A4C) views are interchangeable at the individual level. METHODS: We conducted a secondary cross-sectional agreement analysis of anonymized echocardiographic data acquired in Dalian, China, from January 2021-January 2022. The primary analysis included 115 of 120 screened adults after prespecified eligibility and audit-stage exclusions; sensitivity analyses retained all 120. Paired measurements comprised tricuspid annular plane systolic excursion (TAPSE), lateral tricuspid annular S', e', and a' velocities, and tissue motion annular displacement (TMAD)-derived indices. Observer reproducibility was evaluated in 30 cases. RESULTS: TAPSE was similar between standard and RV-focused views (22.4 ± 3.6 vs 22.4 ± 3.2 mm; mean difference, -0.09 mm; p = 0.805), and other group-level differences were small. Individual agreement was limited: intraclass correlation coefficients (ICCs) were 0.40 for TAPSE, 0.45-0.65 for tissue Doppler velocities, and 0.39-0.68 for TMAD indices. Sensitivity-analysis ICCs remained poor to moderate (0.21-0.65). Intraobserver and interobserver ICCs in the 30-case subset were 0.97-1.00 and 0.94-0.99, respectively. CONCLUSION: Standard and RV-focused A4C views produced similar group means but only poor-to-moderate individual agreement. The acquisition view should be kept consistent and documented in serial reports and research datasets.