Study Of Myocardial Contraction Fraction Based On CMR-Cine Sequence As A Marker For Evaluating The Severity Of Hypertrophic Cardiomyopathy

Purpose: Myocardial contraction fraction(MCF)can provide information for the prognosis and differential diagnosis of patients with hypertrophic cardiomyopathy(HCM).However,there have been no reports on the value of MCF in patients with varying severity of HCM.The purpose of this study is to use MCF calculated by cardiac magnetic resonance(CMR)to evaluate the overall cardiac function in patients with HCM,and to explore the feasibility of MCF as an imaging parameter to evaluate the severity of HCM.Materials and methods: Imaging data was collected retrospectively from 60 HCM patients and 20 healthy controls who completed the CMR examination.MCF was calculated by dividing left ventricular stroke volume(LVSV)by left ventricular myocardial volume(LVMV).The difference in MCF between late gadolinium enhancement(LGE)-positive and LGE-negative patients were compared.The differences in MCF were compared among patients with stage Ⅱ,Ⅲ and Ⅳ of HCM.Binary logistic regression analysis was used to detect independent discriminants of more severe HCM.Receiver operating characteristic analysis differentiated HCM with different clinical stages.Results: Compared with controls(110.67±20.40%,P<0.001),values for MCF were significantly reduced in HCM(61.40±15.60%).The MCF reduction in LGE detected by CMR was more significant than in HCM patients without LGE(53.15±10.67% vs.76.72±11.04%,P<0.001).Patients with stage IV of HCM had the lowest MCF(45.36±10.97%,P<0.05 vs.stage II and stage III).Multivariate Logistic regression analysis showed that the lower MCF remains an independent discriminator for more severe HCM(stage Ⅱ vs.stage Ⅲ,odds ratio: 0.846;stage Ⅲ vs.stage Ⅳ,odds ratio: 0.877,all P<0.05).The optimal cut-off value for detecting more severe HCM is MCF under 66.40%(stage Ⅱ vs.stage Ⅲ,P<0.05)and 44.75%(stage Ⅲ vs.stage Ⅳ,P<0.05).Conclusion: MCF may be a novel and simple imaging indicator to evaluate myocardial function in patients with HCM and provides important clinical application value in the different severity of HCM.