Characteristics of the right ventricle in left ventricular noncompaction with reduced ejection fraction in the light of dilated cardiomyopathy

Abstract

Background: Reports of left ventricular noncompaction (LVNC) rarely include descriptions of the right ventricle (RV). This study aimed to describe the characteristics of the RV in LVNC patients with reduced LV function (LVNC-R) compared with patients with dilated cardiomyopathy (DCM) and subjects with LVNC with normal left ventricular ejection fraction (LV-EF) (LVNC-N).

Methods: Forty-four LVNC-R patients, 44 LVNC-N participants, and 31 DCM patients were included in this retrospective study (LV-EF: LVNC-R: 33.4±10.2%; LVNC-N: 65.0±5.9%; DCM: 34.6±7.9%). Each group was divided into two subgroups by the amount of RV trabeculation.

Results: There was no difference in the RV-EF between the groups, and the RV trabecular mass correlated positively with the RV volume and negatively with the RV-EF in all the groups. All the measured parameters were comparable between the groups with decreased LV function. The hypertrabeculated RV subgroups showed significantly higher RV volumes and lower RV-EF only in the decreased-LV-function groups. The correlation of LV and RV trabeculation was observed only in the LVNC-N group, while LV trabeculation correlated with RV volumes in both noncompacted groups. Both decreased-LV-function groups had worse RV strain values than the LVNC-N group; however, RV strain values correlated with RV trabeculation predominantly in the LVNC-R group.

Conclusions: The presence and characteristics of RV hypertrabeculation and the correlations between LV trabeculation and RV parameters raise the possibility of RV involvement in noncompaction; moreover, RV strain values might be helpful in the early detection of RV function deterioration.

Fig 1. Representative cardiac MRI images of the studied populations in short axis view with the applied contouring technique and trabecular quantification.

Conventional, manually corrected semiautomatic contours with the threshold-based trabecular quantification method: the green area represents the left ventricular trabeculation, and the blue area represents the right ventricular trabeculation. DCM: dilated cardiomyopathy, LVNC-N: left ventricular noncompaction with good LV function, LVNC-R: left ventricular noncompaction with reduced LV function, RV-HT: right ventricle with hypertrabeculation, RV-NT: right ventricle with normal trabeculation. red line: left ventricular endocardial border, green line: left ventricular epicardial border, yellow line: right ventricular endocardial border, blue line: right ventricular epicardial border.

Fig 2. Comparison of the subgroups with normal RV trabeculation (NT) and with RV hypertrabeculation (HT) within the groups (values of the represented parameters are shown in S4 Table).

DCM-HT: dilated cardiomyopathy with right ventricular hypertrabeculation, DCM-NT: dilated cardiomyopathy with normal right ventricular trabeculation, LVNC-N-HT: left ventricular noncompaction with good left ventricular function and right ventricular hypertrabeculation, LVNC-N-NT: left ventricular noncompaction with good left ventricular function and normal right ventricular trabeculation, LVNC-R-HT: left ventricular noncompaction with reduced left ventricular function and right ventricular hypertrabeculation, LVNC-R-NT: left ventricular noncompaction with reduced left ventricular function and normal right ventricular trabeculation, RV-CMi: right ventricular end-diastolic compact myocardial mass index, RV-EDVi: right ventricular end-diastolic volume index, RV-EF: right ventricular ejection fraction, RV-ESVi: right ventricular end-systolic volume index, RV-FWS: right ventricular free-wall strain, RV-GLS: right ventricular global longitudinal strain, RV-SS: right ventricular septal strain, RV-SVi: right ventricular stroke volume index, RV-TMi: right ventricular end-diastolic trabecular and papillary muscle mass index.