Right Ventricular Diastolic Function in Congenital Heart Disease

Abstract

Assessing right ventricular (RV) function is a major challenge in patients with congenital heart disease. This is related, in part, to complex RV geometry, variable loading conditions, and lack of understanding of RV remodelling in different disease states. Nevertheless, the topic is highly relevant to the field of congenital heart disease since RV function is a critical determinant of clinical status and outcomes in a considerable number of patients. In adults with congenital heart disease, cardiac magnetic resonance imaging is currently considered the gold standard for assessing RV systolic function by determining the RV ejection fraction. While various echocardiographic techniques and parameters have been proposed to quantify RV function, all have associated limitations, and their prognostic value remains uncertain. In a manner analogous to the left ventricle, RV diastolic performance is a potentially more sensitive indicator of cardiovascular pathology than systolic dysfunction is. Hypertrophic and fibrotic myocardial remodelling changes associated with certain congenital heart defects may significantly affect RV filling characteristics. While systolic and diastolic function are generally correlated, diastolic dysfunction may be present despite preserved systolic function. Perhaps the best studied and most telling example of the importance of RV diastolic dysfunction is in patients with tetralogy of Fallot in whom restrictive RV physiology is diagnosed on the basis of late diastolic anterograde flow in the pulmonary trunk throughout the respiratory cycle. Such forward diastolic flow reflects increased RV end-diastolic pressure related to decreased RV compliance. It effectively limits pulmonary regurgitation and protects against progressive RV dilatation. The prognostic value of this imaging metric is not fully understood, and the topic remains a source of controversy. Within this context, the novel approaches proposed by Addetia et al. to assessing RV function are of tremendous interest to the