Mechanical contraction patterns of the systemic right ventricle: a 3D echocardiography study

Abstract

Funding Acknowledgements Type of funding sources: None. Background. In patients with transposition of great arteries (TGA) post atrial switch operation or with congenitally corrected TGA (ccTGA), the morphologically right ventricle (RV) has to adapt to the chronically increased systemic pressure. Purpose. To investigate the functional adaptation of the systemic RV in patients with TGA post Mustard repair or ccTGA. Methods. RV volumes and EF were measured by 3D echocardiography in 33 patients with the systemic RV (21 TGA and 12 ccTGA; 45 ± 13y, 61% male), and in 33 healthy volunteers (44 ± 13y, 61% male). The 3D RV model was postprocessed by the ReVISION software and its contraction was decomposed along the longitudinal, radial and anteroposterior directions (Fig.A, Systemic RV in TGA) providing longitudinal, radial and anteroposterior EF (LEF, REF and AEF). Relative contribution of each component was measured as the ratio between LEF, REF and AEF to the global RVEF (LEFi, REFi and AEFi). Results. Systemic RV was significantly larger with reduced function compared to controls (Tab). 3D RVEF demonstrated stronger correlation with BNP (Rho -0.76, p < 0.0001) compared to other parameters of RV function (free wall strain 0.55, p = 0.0083; FAC -0.47, p = 0.024; S’ -0.39 and TAPSE 0.06, p > 0.05). While in healthy volunteers, all 3 components of RV systolic function contributed equally to the global RV EF, in patients with TGA the relative contribution of the anteroposterior component was dominant and differed significantly from longitudinal and radial components (AEFi 0.48 ± 0.06 vs LEFi 0.31 ± 0.07 vs REFi 0.36 ± 0.09, p < 0.0001)(Fig. B,C). In patients with ccTGA the longitudinal component was dominant and provided a relative compensation for the reduced anteroposterior and radial components (LEFi 0.47 ± 0.07 vs AEFi 0.34 ± 0.07, p = 0.0002 and vs REFi 0.36 ± 0.09, p = 0.0023)(Fig. B,C). Relative contribution of the radial contraction was significantly reduced in all systemic RV patients. Conclusions. Systemic RV contraction patterns change significantly with anteroposterior contraction being dominant in patients with TGA post Mustard repair and longitudinal component being dominant in ccTGA. 3DE should be a part of routine assessment of the systemic RV, especially in TGA since no conventional echo parameters take into account anteroposterior RV contraction. Parameters of RV systolic function Parameter Control group (N = 33) All SRV patients (N = 33) TGA (N = 21) ccTGA (N = 12) 3D EF, % 60 ± 3.8 36 ± 8.6* 34 ± 7.3* 38 ± 10* FAC, % 41.4 ± 3.7 25.9 ± 9.3* 25.1 ± 9.2* 27.1 ± 9.9* TAPSE, mm 24.6 ± 4.2 11.9 ± 3.9* 11.1 ± 2.9* 13.2 ± 5.1* RV free wall strain, % -32.5 ± 4.2 -14.5 ± 3.5* -14.5 ± 2.9* -15.5 ± 3.5* * p < 0.0001 Abstract Figure.

Multi‐modality imaging of the systemic right ventricle in congenital heart disease

“…[11][12][13] Moreover, previous studies which associated TAPSE with N-terminal probrain natriuretic peptide (NT-proBNP) have been contradictory. 4,14 A threshold of 10 cm/s for RV S' has been reported by Khattab et al for adults with sRV. 9 In a study of 35 patients with TGA and atrial switch, sRV S' was moderately correlated with CMR-derived sRVEF.…”

“…In TGA, the anteroposterior component predominates in the total sRVEF, implying that the longitudinal and radial shortening of the sRV is diminished. In contrast, in patients with ccTGA the three components are equally responsible for the pump function of the sRV 4 …”

“…Additionally, a recent study of 38 patients with sRV (24 with TGA after atrial switch and 14 with ccTGA) demonstrated a strong correlation between 3DE sRVEF and BNP plasma concentration. Intra‐ and interobserver variability and reliability for sRV volumes and sRVEF were also acceptable 4 . A three‐dimensional sRVEF cutoff value of 45% has been proposed 10 …”

“…However, evidence from several studies of patients with TGA after atrial switch accumulates no correlation between sRVEF and TAPSE 11–13 . Moreover, previous studies which associated TAPSE with N‐terminal probrain natriuretic peptide (NT‐proBNP) have been contradictory 4,14 . A threshold of 10 cm/s for RV S’ has been reported by Khattab et al.…”

“…Nonetheless, FAC calculation includes the circumferential contraction pattern of the RV free wall, while it does not take into account the contribution of the RV outflow tract to overall systolic function 16 . In patients with sRV, a cut‐off FAC value of 29.5%–33% has been previously proposed 4,9,10,13 …”