Abstract
BACKGROUND
Several studies suggest that mitral valve prolapse (MVP) can be related to sudden cardiac death, owing to sustained ventricular arrhythmias (VAs). In patients with sudden cardiac death and complex VAs, a high percentage of either left ventricle (LV) papillary muscle fibrosis or inferobasal fibrosis has been described using cardiac magnetic resonance (CMR) with late gadolinium enhancement technique (LGE). However, LGE presents several technical limitations and requires contrast agent administration. Thanks to T1 mapping (T1-map) and feature tracking (FT) techniques, CMR may identify myocardial fibrosis and deformation abnormalities respectively. We sought to demonstrate that, in patients with MVP, T1 map can accurately identify the presence of myocardial fibrosis which, being related to myocardial stiffness, is associated to abnormal deformation indexes at CMR FT strain evaluation.
METHODS
Consecutive patientswith indication to mitral valve surgery for severe mitral regurgitation due to mitral valve prolapse were prospectively enrolled. CMR including Modified Look-Locker (MOLLI) sequences for T1 mapping was performed in each patient. In addition, CMR FT analysis of steady state free precession (SSFP) cine images was performed to obtain 2D global and segmental circumferential and radial strains.
RESULTS
70 consecutive patients (age: 59 ± 12) were successfully evaluated with CMR. T1 native values were significantly higher in the basal and mid LV inferolateral wall compared to the remote myocardium (1074 ± 67 vs 1046 ± 40 msec, p< 0.001). Moreover, the average radial and circumferential strains of the basal and mid LV inferolateral were significantly reduced compared to those of the remote myocardium (21.1 ± 10.4 and -12.8 ± 5.6 vs 31.6 ± 9.1 and -17.3 ± 3.6 respectively, p < 0.001).
CONCLUSIONS
In patients with MVP and severe mitral regurgitation native T1 values of the LV inferolateral are higher as compared to remote myocardium and associated with reduced circumferential and radial strains. T1 mapping and CMR FT strain may be used as tools for the early identification of tissue changes in the LV inferolateral myocardial segment. Further studies are needed to evaluate if these changes are able to predict LGE development and are associated with higher risk for VAs
Mapping of mitral regurgitant defects by cardiovascular magnetic resonance in moderate or severe mitral regurgitation secondary to mitral valve prolapse
