Atrial Functional Tricuspid Regurgitation as a Distinct Pathophysiological and Clinical Entity: No Idiopathic Tricuspid Regurgitation Anymore.

Functional tricuspid regurgitation (FTR) is a strong and independent predictor of patient morbidity and mortality if left untreated. The development of transcatheter procedures to either repair or replace the tricuspid valve (TV) has fueled the interest in the pathophysiology, severity assessment, and clinical consequences of FTR. FTR has been considered to be secondary to tricuspid annulus (TA) dilation and leaflet tethering, associated to right ventricular (RV) dilation and/or dysfunction (the "classical", ventricular form of FTR, V-FTR) for a long time. Atrial FTR (A-FTR) has recently emerged as a distinct pathophysiological entity. A-FTR typically occurs in patients with persistent/permanent atrial fibrillation, in whom an imbalance between the TA and leaflet areas results in leaflets malcoaptation, associated with the dilation and loss of the sphincter-like function of the TA, due to right atrium enlargement and dysfunction. According to its distinct pathophysiology, A-FTR poses different needs of clinical management, and the various interventional treatment options will likely have different outcomes than in V-FTR patients. This review aims to provide an insight into the anatomy of the TV, and the distinct pathophysiology of A-FTR, which are key concepts to understanding the objectives of therapy, the choice of transcatheter TV interventions, and to properly use pre-, intra-, and post-procedural imaging.

Right heart chambers geometry and function in patients with the atrial and the ventricular phenotypes of functional tricuspid regurgitation.

AIMS: Atrial functional tricuspid regurgitation (A-FTR) is a recently defined phenotype of functional tricuspid regurgitation (FTR) associated with persistent/permanent atrial fibrillation. Differently from the classical ventricular form of FTR (V-FTR), patients with A-FTR might present with severely dilated right atrium and tricuspid annulus (TA), and with preserved right ventricular (RV) size and systolic function. However, the geometry and function of the right ventricle, right atrium, and TA in patients with A-FTR and V-FTR remain to be systematically evaluated. Accordingly, we sought to: (i) study the geometry and function of the right ventricle, right atrium, and TA in A-FTR by two- and three-dimensional transthoracic echocardiography; and (ii) compare them with those found in V-FTR. METHODS AND RESULTS: We prospectively analysed 113 (44 men, age 68 ± 18 years) FTR patients (A-FTR = 55 and V-FTR = 58) that were compared to two groups of age- and sex-matched controls to develop the respective Z-scores. Severity of FTR was similar in A-FTR and V-FTR patients. Z-scores of RV size were significantly larger, and those of RV function were significantly lower in V-FTR than in A-FTR (P < 0.001 for all). The right atrium was significantly enlarged in both A-FTR and V-FTR compared to controls (P < 0.001, Z-scores > 2), with similar right atrial (RA) maximum volume (RAVmax) between A-FTR and V-FTR (P = 0.2). Whereas, the RA minimum volumes (RAVmin) were significantly larger in A-FTR than in V-FTR (P = 0.001). CONCLUSION: Despite similar degrees of FTR and RAVmax size, A-FTR patients show larger RAVmin and smaller TA areas than V-FTR patients. Conversely, V-FTR patients show dilated, more elliptic and dysfunctional right ventricle than A-FTR patients.

Automated left atrial volume measurement by two-dimensional speckle-tracking echocardiography: feasibility, accuracy, and reproducibility.

AIMS: A byproduct of left atrial (LA) strain analysis is the automated measurement of LA maximal volume (LAVmax), which may decrease the time of echocardiography reporting, and increase the reproducibility of the LAVmax measurement. However, the automated measurement of LAVmax by two-dimensional speckle-tracking analysis (2DSTE) has never been validated. Accordingly, we sought to (i) assess the feasibility of automated LAVmax measurement by 2DSTE; (ii) compare the automated LAVmax by 2DSTE with conventional two-dimensional (2DE) biplane and three-dimensional echocardiography (3DE) measurements; and (iii) evaluate the accuracy and reproducibility of the three echocardiography techniques. METHODS AND RESULTS: LAVmax (34-197 mL) were obtained from 198/210 (feasibility 94%) consecutive patients (median age 67 years, 126 men) by 2DSTE, 2DE, and 3DE. 2DE and 2DSTE measurements resulted in similar LAVmax values [bias = 1.5 mL, limits of agreement (LOA) ± 7.5 mL], and slightly underestimated 3DE LAVmax (biases = -5 mL, LOA ± 17 mL and -6 mL, LOA ± 16 mL, respectively). LAVmax by 2DSTE and 2DE were strongly correlated to those obtained by cardiac magnetic resonance (CMR) (r = 0.946 and r = 0.935, respectively; P < 0.001). However, LAVmax obtained by 2DSTE (bias = -9.5 mL, LOA ± 16 mL) and 2DE (bias = -8 mL, LOA ± 17 mL) were significantly smaller than those measured by CMR. Conversely, 3DE LAVmax were similar to CMR (bias = -2 mL, LOA ± 10 mL). Excellent intra- and inter-observer intraclass correlations were found for 3DE (0.995 and 0.995), 2DE (0.990 and 0.988), and 2DSTE (0.990 and 0.989). CONCLUSION: Automated LAVmax measurement by 2DSTE is highly feasible, highly reproducible, and provided similar values to conventional 2DE calculations in consecutive patients with a wide range of LAVmax.