0164: Validation of two-dimensional speckle tracking strain for assessment of early right ventricular dysfunction: in vivo and ex vivo study - 12/02/16
Résumé |
Background |
Right ventricular (RV) dysfunction is a major determinant of long-term survival in congenital heart diseases. Early echo detection of RV failure is mandatory, but recent indices need to be validated.
Aims |
Objectives were to: (1) validate standard and strain echo indices for evaluation of RV systolic function, compared to hemodynamic parameters; (2) assess the accuracy of these indices for early detection of RV failure.
Methods |
Combined RV overload as observed in repaired tetralogy of Fallot was surgically reproduced in 2-month-old piglets (n=6). Age-matched piglets were used as controls (n=4). RV function was evaluated at baseline and 4 months of follow-up by standard and strain echo indices, compared to conductance catheter. Sarcomere shortening and calcium transients were recorded in RV isolated myocytes (IonOptix). Contractile reserve was assessed by in-vivo (dobutamine 5µg/kg) and ex-vivo (isoprenaline 100nM) β adrenergic stimulation. The integrity of T-tubules was controlled after Di-4-Anepps labeling.
Results |
4 months after surgery, hemodynamic RV ejection fraction (FEVD) was significantly decreased (29.7% [26.2-34] vs 42.9% [40.7-48.6], p<0.01), and inotropic responses to dobutamine were blunted (contractile reserve ΔEmax=51% vs 193%, p<0.05). On echocardiography FAC, TAPSE, S’ peak and RV free wall longitudinal strain rate were significantly reduced and correlated with FEVD. Peaks strain rate and S’ were correlated with ΔEmax (r=0.75 and 0.78, p<0.05). Isolated RV myocytes from operated animals showed hypertrophy, decreased sarcomere shortening peak in response to isporenaline (ΔL=7.8±2.8% vs 10.7±2.9%, p<0.05), and increased spontaneous calcium waves suggesting perturbations of calcium homeostasis.
Conclusion |
In this model, both standard and strain echo indices allowed the detection of early impairments of RV function and cardiac reserve, which are associated with cardiac excitation-contraction coupling alterations.
Le texte complet de cet article est disponible en PDF.Vol 8 - N° 1
P. 100 - janvier 2016 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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