Right ventricular outflow tract systolic excursion: a useful method for determining right ventricular systolic function

Right ventricle: current knowledge of echocardiographic evaluation of this "forgotten" chamber

In the past the right ventricle (RV) has been traditionally regarded as a simple conduit between the venous system and the pulmonary circulation and it has aroused little interest in both clinical and echocardiographic cardiologists to such an extent that it has been defined as the "forgotten chamber." Subsequently it was clearly shown that the right heart (RH) plays an important physiologic role in cardiac activity, and that congenital or acquired alterations in its structure and function have an important prognostic value. Aim of this review is to shed the light on the echocardiographic approach to this cardiac chamber. In this narrative review we critically explored the most recent literature on this topic using PubMed and Medline and examining the most recent guidelines on the echocardiographic approach to the RV. Echocardiographic approach to RV presents some technical difficulties, which stem from the position of the RV inside the thorax and around the LV and from its particular anatomy, which precludes geometric assumptions. However, RV may now be evaluated quantitatively and qualitatively in many ways, and some new methods can partially overcome some of the limits imposed by its complex anatomy, thereby yielding a quantitative evaluation. Furthermore, due to the wide range of pathologies which may involve the RV a disease-oriented approach should be considered in the echocardiographic investigation of right heart disease.

The relation of right ventricular outflow tract measurements with in-hospital clinical outcomes after tricuspid valve surgery

Right ventricular (RV) function is a determining factor for clinical outcomes in patients undergoing tricuspid valve surgery (TVS). Our aim was to investigate the importance of the function of the right ventricular outflow tract (RVOT), which is an important anatomical region of the RV, in patients underwent TVS. 104 patients who underwent TVS were analyzed retrospectively. Patients with previous cardiac surgery, congenital heart disease, or heart failure were excluded. The parasternal short-axis view at the level of the aortic root was used to measure RVOT dimensions and RVOT fractional shortening (RVOT-FS). The effect of RVOT diameter and function on major adverse cardiac events (MACE) after TVS was investigated. In our study, MACE, consisting of pacemaker implantation, acute kidney injury, postoperative atrial fibrillation and mortality, was developed at 44 (42.3%) patients.We compared the predictive performances of RVOT end-systolic (RVOTs) diameter, RVOT end-diastolic (RVOTd) diameter, RVOT-FS and RV diameters in prediction of MACE. The model including the RVOTs had higher AUC, R2 and likelihood ratio X2 values (0.775, 0.287 and 25.0, respectively) than RVOTd (0.770, 0.279 and 24.2, respectively) and RVOT-FS (0.750, 0.215 and 18.1, respectively). RVOT diameters showed better performance in predicting MACE than RV diameters. Moreover, there was statistically significant association between RVOTs, RVOTd and MACE (p value were 0.014 and 0.027, respectively), while no association between RVOT-FS and MACE (p value was 0.177). In summary, we determined that the RVOT diameters are important predictors for the in-hospital clinical outcomes of patients who underwent TVS.

Non-invasive imaging of global and regional cardiac function in pulmonary hypertension

Pulmonary hypertension (PH) is a progressive illness characterized by elevated pulmonary artery pressure; however, the main cause of mortality in PH patients is right ventricular (RV) failure. Historically, improving the hemodynamics of pulmonary circulation was the focus of treatment; however, it is now evident that cardiac response to a given level of pulmonary hemodynamic overload is variable but plays an important role in the subsequent prognosis. Non-invasive tests of RV function to determine prognosis and response to treatment in patients with PH is essential. Although the right ventricle is the focus of attention, it is clear that cardiac interaction can cause left ventricular dysfunction, thus biventricular assessment is paramount. There is also focus on the atrial chambers in their contribution to cardiac function in PH. Furthermore, there is evidence of regional dysfunction of the two ventricles in PH, so it would be useful to understand both global and regional components of dysfunction. In order to understand global and regional cardiac function in PH, the most obvious non-invasive imaging techniques are echocardiography and cardiac magnetic resonance imaging (CMRI). Both techniques have their advantages and disadvantages. Echocardiography is widely available, relatively inexpensive, provides information regarding RV function, and can be used to estimate RV pressures. CMRI, although expensive and less accessible, is the gold standard of biventricular functional measurements. The advent of 3D echocardiography and techniques including strain analysis and stress echocardiography have improved the usefulness of echocardiography while new CMRI technology allows the measurement of strain and measuring cardiac function during stress including exercise. In this review, we have analyzed the advantages and disadvantages of the two techniques and discuss pre-existing and novel forms of analysis where echocardiography and CMRI can be used to examine atrial, ventricular, and interventricular function in patients with PH at rest and under stress.