LAUSR

Atrial fibrillation (Afib) leads to beat-to-beat variability in cycle length; however, whether there is associated beat-to-beat variability in the tricuspid annulus (TA) dimensions or variability in the time in cardiac cycle when TA reaches maximal size is unknown. We aim to assess the beat-to-beat variability in the TA dimensions in Afib compared with sinus rhythm (SR). Images were obtained from 58 patients (29 in Afib, 29 in SR) undergoing either 3D TTE or TEE examination. We measured TA in 3–6 cardiac cycles per patient using commercially available software (TomTec 4MV). Median absolute difference in maximal TA area over 3–6 cardiac cycles was 1.60 cm2 (range 0.35 cm2 to 4.08 cm2) in Afib vs. 1.17 cm2 (range 0.32 cm2 to 2.19 cm2) in SR, p=0.0063. Median absolute difference in the maximal circumference was 0.79 cm (range 0.09 cm to 2.2 cm) in Afib vs 0.54 cm (range 0.12 cm to 1.43 cm) in SR, p=0.0175. A total of 118 cardiac cycles were analyzed in patients in SR and 147 in Afib. Timing of maximal TA area was most commonly recorded at end-diastole (80–100% of the R-R interval) in 62% of cycles in SR; however, it was distributed over a broad range in Afib, p<0.0001, [Figure]. Afib leads to significant beat-to-beat variability in the maximal TA area, minimal TA area, maximal TA circumference, and in the time of maximal TA area. These findings suggest that accurate assessment of TA dimensions should be based on continuous tracking of the TA over several cardiac cycles, especially in patients with Afib. These observations have significant implications for device sizing in percutaneous tricuspid valve interventions. Timing of Maximal TA Area Type of funding source: None