Multimodality Imaging Assessment of the Severity of Mitral Regurgitation

Inclusion Criteria: 1. age ≥ 18 years old 2. all-caused moderate or severe MR assessed by Trans-Thoracic Echocardiography (TTE) : 1) EROA ≥0.3cm\^2; 2) RVol ≥45ml 3. The patient has signed an informed consent form. Exclusion Criteria: 1. unstable angina, acute myocardial infarction and surgical history of coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) within 3 months before recruit 2. acute heart failure or acute worsening of chronic heart failure requiring vasoactive drug therapy 3. severe infections, septicaemia 4. severe hepatic insufficiency ( Child-Pugh class C) 5. severe renal insufficiency ( chronic kidney disease (CKD) stage 5: estimated glomerular filtration rate (eGFR) \<15ml/min or dialysis) 6. hypotensive state, shock ( systolic blood pressure \<90mmHg or mean arterial pressure \<70mmHg with tissue hypoperfusion and urine output \<30ml/h) 7. uncontrolled diseases of the haematological system: acute gastrointestinal bleeding, intracranial haemorrhage or haemorrhage from other organs, acute pulmonary embolism or deep vein thrombosis, congenital or acquired haemorrhagic disease such as haemophilia, anaphylactic purpura and acute leukaemia, severe abnormalities in haematological parameters such as platelet count \<20\*10\^9/l and international normalized ratio (INR) \>3 8. contraindication for Trans-Esophageal Echocardiography (TEE) such as oesophageal constriction, oesophageal tumour, oesophageal fistula, oesophageal varices, cervical vertebral instability 9. contraindication for CMR such as metal foreign matter in the body, claustrophobia 10. contraindication for intravenous anaesthesia such as allergy to anaesthetics 11. pregnancy or breastfeeding 12. The patient does not sign an informed consent form. 13. Due to other reasons the patient is not suitable for enrollment assessed by the researcher.