Evaluation and implications of mitral regurgitation using cMRI in patients with hypertrophic cardiomyopathy.

OBJECTIVE: Mitral regurgitation (MR) represents an important feature in patients with hypertrophic cardiomyopathy (HCM) due to left ventricular outflow tract (LVOT) obstruction and mitral valve systolic anterior motion (SAM). Mitral valve anatomical variants associated with HCM also contribute to the severity of MR. The aim of this study is to evaluate MR severity and its correlation with different parameters in patients with HCM using cardiac magnetic resonance imaging (cMRI). PATIENTS AND METHODS: 130 patients with HCM underwent cMRI. Parameters assessed for the quantification of MR severity were mitral regurgitation volume (MRV) and mitral regurgitation fraction (MRF). cMRI was also used to characterize LV function, left atrium volume (LAV) index, filling pressures and structural abnormalities associated with HCM, all in correlation to MR. RESULTS: Patients with HCM had mild (26.9%), moderate (52.3%) or severe (20.7%) MR. Most relevant parameters related to MR severity were MRV and MRF; other parameters with strong correlation with MR were LAV index and E/E' ratio, both increasing with its severity. Patients with LVOT obstruction had more severe MR (70.3%), 79% of them due to SAM. LV ejection fraction (LVEF) increased proportionally with the severity of MR, while LV strain (LAS) was inversely correlated with it. Independent predictors for quantifying the severity of MR, after the adjustment for covariates, were MRV, MRF, SAM, LAV index and E/E'. CONCLUSIONS: cMRI can accurately assess MR in patients with HCM, especially by using novel indicators, MRV and MRF respectively, along with LAV index and E/E' ratio. Severe MR, due to SAM, is more frequent in the obstructive form of HCM (HOCM). Also, the severity of MR is significantly associated with significantly associated with MRV, MRF, LAV index and E/E' ratio.

Characterization of left atrial geometry and function in patients with hypertrophic cardiomyopathy: a cardiac magnetic resonance imaging study.

OBJECTIVE: Left atrial (LA) remodelling is an interesting pathological aspect in hypertrophic cardiomyopathy (HCM) which has not been yet fully understood. Also, a comprehensive evaluation of LA alterations in HCM is still lacking. Cardiac magnetic resonance imaging (cMRI) can precisely characterize LA function and structure. We sought to thoroughly assess LA remodelling using cMRI in patients with HCM. PATIENTS AND METHODS: We enrolled 105 patients with HCM and 105 healthy controls. LA parameters determined by cMRI comprise LA volume (LAV), total ejection fraction (LATF), total strain LA- εt, passive ejection fraction (LAPF), passive strain LA-εe, active ejection fraction (LAAF), active strain LA-εa. LA sphericity index (LASI) and LA strain were also determined. Parameters of LV systolic and diastolic functions were also assessed. RESULTS: LAV and LASI were significantly increased, while LA phasic functions were decreased in patients with HCM (p<.001). LATF was inversely correlated with LV long-axis strain (r= -0.466, p<.0001) and mass (r= -0.515, p<.0001), and as well with filling pressures, described by E/E' (r= -0.424, p<.0001). LA volumes, phasic functions and geometry were negatively associated with LV measurements, whereas a positive correlation between the LATF and LA strain (r = 0.496, p<.0001) was found. In addition, LAV was closely related to diastolic dysfunction severity (p<.0001). CONCLUSIONS: In patients with HCM, all three LA phasic functions were impaired, being directly related to LA enlargement. LASI and LA strain predicted LA reservoir function impairment.