Is systemic right ventricular function by cardiac MRI related to the degree of tricuspid regurgitation in congenitally corrected transposition of the great arteries?

Background and MethodsSystemic right ventricular dysfunction and tricuspid regurgitation (TR) are frequently encountered in patients with congenitally corrected transposition of the great arteries (CCTGA). Studies using echocardiography have suggested a relationship between the degree of TR and systemic right ventricular dysfunction; however, assessment of systemic right ventricular function by echocardiography is limited. Cardiac MRI (CMR) is the gold standard for volumetric assessment of the systemic right ventricle. We performed a retrospective cohort study at our center evaluating all adult patients with CCTGA who underwent a CMR between 1/1999 and 1/2013 to determine the relationship between the degree of TR and systemic right ventricular function.ResultsOf the 33 patients identified, 12 had ≤ mild TR (37%), 13 had moderate TR (40%), and 8 had severe TR (24%). Mean age at CMR was 38 years (23-64). Mean right ventricular ejection fraction (45% vs. 41% vs. 42%, p = 0.68) and mean indexed right ventricular end diastolic volume (122 ml/m2 vs. 136 ml/m2 vs. 138 ml/m2p = 0.36) were not significantly different for patients with ≤ mild TR, moderate TR or severe TR. The degree of TR was not associated with additional congenital lesions, prior procedures, presence of an intraventricular conduction delay, or decreased left ventricular function.ConclusionNo association between the degree of TR and right ventricular volume or ejection fraction by CMR was identified. Failure to show worsening function or increased volume with greater degrees of TR suggests that the degree of regurgitation alone may not fully explain the heterogeneity in right ventricular size and function.