Prospective, multicenter, observational study to enroll consecutive patients with functional tricuspid regurgitation (FTR) with the primary aim to:

• Use patients' outcomes as a reference to try to define the threshold values for the different grades of FTR severity; and secondary aims to:
• Use 3D echocardiography to assess the relationships among the geometry (size and shape) of the right ventricle, right atrium, tricuspid annulus, and tricuspid leaflets according to the underlying cardiac condition (i.e., atrial fibrillation, pulmonary hypertension, right ventricular cardiomyopathy, congenital heart diseases, etc.)
• Assess the accuracy, and incremental diagnostic and prognostic value of a new software package to measure tricuspid annulus and valve geometry
• Develop new parameters of FTR severity that take into account the lower momentum of the tricuspid regurgitant jet (compared with the mitral regurgitation jet), the complex anatomy of the regurgitant orifice, and both the intra-beat and respiratory variation of the regurgitant volume
• Test the hypothesis that there is no actual grading but a continuum of increased risk of adverse outcome with the increase of FTR severity, and we need robust quantitative metrics (for example, the regurgitant fraction - currently not included in guidelines - which takes into account the right ventricular volume and function) more than grading schemes to assess the severity of the diseases and the effect of treatments
• Test the hypothesis that the relationship between FTR severity and the outcome may be different according to the underlying cardiac condition (i.e., atrial fibrillation, pulmonary hypertension, right ventricular cardiomyopathy, congenital heart diseases, post-cardiac surgery, etc.) as this will affect the timing for interventions

Inclusion Criteria:

• older than 18 years,
• signed informed consent to be part of this study,
• no pregnancy,
• the presence of at least one of the following cardiac conditions: a. Permanent atrial fibrillation b. Pulmonary arterial hypertension c. Left heart diseases with increased postcapillary pressure d. Right ventricular cardiomyopathy e. Right ventricular infarction f. Chronic thromboembolic pulmonary embolism g. Congenital diseases with right ventricular volume overload (atrial septal defect, interventricular septal defect, pulmonary regurgitation) h. Previous left heart valve surgery I. Good enough acoustic window and patient cooperation to obtain 3D echo data sets of the right ventricle, right atrium and tricuspid valve with a minimum temporal resolution of 20 vps l. Availability for clinical and echocardiography follow-up

Exclusion Criteria:

• Unwillingness to be part of the study
• Primary tricuspid valve disease
• Patient already scheduled for tricuspid valve repair/replacement
• Cardiac pacemaker, ICD or CRT leads
• Poor acoustic window
• Impossibility of left lateral decubitus position
• Extreme heart rates (<50 or >100 bpm)
• Previous LVAD implantation

Patients with at least mild functional tricuspid regurgitation and good apical acoustic window

Data will be made available upon reasonable request