Tricuspid annulus dynamics in atrial fibrillation compared to sinus rhythm using 3-D echocardiography: relation with tricuspid regurgitation

Abstract Funding Acknowledgements Type of funding sources: None. Background Atrial fibrillation (AF) is known to cause dilation in both the mitral (MA) and the tricuspid (TA) annuli. Few studies have investigated MA dynamics and function in AF compared to sinus rhythm (SR). However, no study addressed this issue in TA. Hence, we set forth to describe TA dynamics in AF and SR and its relationship with severity of tricuspid regurgitation (TR). Methods 3D echocardiographic imaging data were acquired from adult patients in AF or SR with varying degrees of TR between 2018 and 2020. TA was automatically tracked throughout the cardiac cycle using a commercially available software (TomTec 4MV software; Figure 1) over 4-6 cardiac cycles per patient. Time to minimal area as percentage of the R-R interval was recorded in each of the cycles. Absolute change in TA area was calculated as the difference between maximal and minimal TA area in each cardiac cycle and was averaged over 4-6 cycles per patient. This measurement was used to reflect the dynamic range of TA deformation during the cardiac cycle. Right atrial (RA) and right ventricular (RV) volumes and longitudinal strain were also measured (speckle tracking, 4-ch view). Results A total of 70 patients were studied (35 AF; 35 SR; 54% males in each group). Patients with AF were older [median (IQR) of 81 (72-86) years vs. 69 (59-78) years in SR, p < 0.001], had larger maximal TA area and circumference (p < 0.001 for both), larger RA size (p < 0.001), lower RA reservoir strain (p < 0.001) and RV free-wall strain (p < 0.001). Absolute change in TA area was significantly decreased in AF [2.3 (1.7-2.7) cm2] vs. 3.1 (2.3-3.5) cm2 in SR, p = 0.002. Patients with ≥ moderate TR (n = 41, 59%) had lower absolute change in TA area [2.4 (1.7-3.1) cm2 vs. 2.8 (2.2-3.5) cm2 in < moderate TR, p = 0.05]. Female sex was associated with lower absolute change in TA area [2.3 (1.7-3.2) cm2 vs. 2.7 (2.2-3.6) cm2 in males, p = 0.02] on univariate analysis. AF patients had more frequently ≥ moderate TR [28 AF vs. 13 SR, p < 0.001]. On multivariate analysis including sex, rhythm, TR severity, RA and RV strains, and averaged maximal TA area, independent factors associated with lower absolute change in TA area were AF, ≥ moderate TR, and larger maximal TA area (p < 0.05 for all). Time to minimal TA size was achieved in (0-40%) of the R-R interval in 70% of patients in SR compared to only 41% of patients in AF (Figure 2) and in 73% in patients with < moderate TR compared to 43% in patients with ≥ moderate TR. Conclusion AF is associated with blunted TA dynamics resulting in lower decrease in TA size and with a heterogenous timing of minimal TA size throughout the cardiac cycle. The blunted and discoordinated annular contraction may reduce systolic tricuspid valve competence and be involved in the pathophysiology of functional TR. Future studies are needed to confirm this hypothesis and evaluate the effect of restoration of SR on TA dynamics and time to minimal TA size. Abstract Figure 1Abstract Figure 2