Atrio-ventricular coupling in patients with transposition of the great arteries after atrial switch by Magnetic Resonance Imaging
© Ladouceur et al; licensee BioMed Central Ltd. 2015
Published: 3 February 2015
Diastolic function has been little explored in d-transposition of the great arteries palliated by atrial switch (d-TGA). However, early detection of diastolic dysfunction could be of major clinical interest and could explain clinical status in this population. We aimed: 1/ to characterize diastolic function in d-TGA after atrial switch from velocity encoded cardiac magnetic resonance (CMR) data and 2/ to study associations between diastolic function indices and objective measurements of clinical status evaluated by exercise test.
CMR diastolic parameters were significantly different in d-TGA patients as compared to controls. In d-TGA patients, parameters of systemic right ventricular (RV) relaxation were markedly impaired compared to left ventricle of controls, as reflected by a significant increase in deceleration and isovolumic relaxation times (p<0.01). Early trans-tricuspid peak filling-rate (Ef) and RV filling duration were negatively correlated with systemic RV remodeling index (Mass/volume) (r=-0.38 and -0.45, respectively, p<0.01). Systemic RV stroke volume and Ef were significantly associated with baffle size (r=0.35 and r=0.33, p≤0.02, respectively). While peak VO2 was not related to systemic RV volumes, RVEF and to RV Mass, it was significantly associated with systemic ventricle filling indices, such as Ef/filling volume, A wave, filling volume. In multivariate analysis, a significant association was found between RA strain and exercise peak oxygen uptake (r=0.42, p<0.01) in d-TGA patients, while systemic RV ejection fraction was not correlated with exercise performances. Such associations were independent of age, gender and body mass index.
In d-TGA after atrial switch, systemic RV exposed to systolic dysfunction can be also characterized by an early impairment of diastolic function. Systemic RV diastolic dysfunction is characterized by abnormal RV relaxation that limits cardiac output augmentation.
This work was supported by Assistance Publique Hôpitaux de Paris. The authors were totally independent of the funder for all scientific aspects of the research.
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