Word count: 4478words (including figures legends and references)Running title: Prognostic role of CMR and conventional risk factors in MINOCA Abstract: Objective: Assess the prognostic impact of Cardiovascular Magnetic Resonance (CMR) and conventional risk factors in patients with Myocardial infarction with non-obstructed coronaries (MINOCA). Background: MINOCA represents a diagnostic dilemma and the prognostic markers have not been clarified. Methods: 388 consecutive MINOCA patients undergoing CMR assessment were identified retrospectively from registry database and prospectively followed up for a primary clinical endpoint of all-cause mortality. 1.5T CMR was performed using a comprehensive protocol (cines, T2-weighted, and late gadolinium enhancement sequences). Patients were grouped into 4 categories based on their CMR findings: myocardial infarction (MI) (embolic/spontaneous recanalization), myocarditis, cardiomyopathy and normal CMR. Results: CMR(performed at a median of 37days from presentation) was able to identify the cause for the troponin rise in 74% of the patients (25% myocarditis, 25% MI and 25% cardiomyopathy), whilst a normal CMR was identified in 26%. Over a median follow-up of 1262days(3.5years), 5.7% patients died. Cardiomyopathy group had the worst prognosis (mortality 15%, log rank 19.9 p<0.001), MI had 4% mortality, and 2% in both myocarditis and normal CMR. In a multivariable cox regression model (including clinical and CMR parameters), CMR diagnosis of cardiomyopathy and ST-segment elevation on presentation ECG remained the only 2 significant predictors of mortality. Using presentation with ECG ST-elevation and CMR diagnosis of cardiomyopathy as risk markers, the mortality risk rates were 2%, 11% and 21% for presence of 0, 1 and 2 factor respectively(p<0.0001). Conclusion: In a large cohort of MINOCA, CMR(median 37days from presentation) identified a final diagnosis in 74% of patients. Cardiomyopathy had the highest mortality, followed by MI. The strongest predictors of mortality were a CMR diagnosis of cardiomyopathy and ST-elevation on presentation ECG.

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Background: There are several methods to quantify mitral regurgitation (MR) by cardiovascular magnetic resonance (CMR). The interoperability of these methods and their reproducibility remains undetermined. Objective: To determine the agreement and reproducibility of different MR quantification methods by CMR across all aetiologies. Methods: Thirty-five patients with MR were recruited (primary MR = 12, secondary MR = 10 and MVR = 13). Patients underwent CMR, including cines and four-dimensional flow (4D flow). Four methods were evaluated: MR Standard (left ventricular stroke volume -aortic forward flow by phase contrast), MR LVRV (left ventricular stroke volume -right ventricular stroke volume), MR Jet (direct jet quantification by 4D flow) and MR MVAV (mitral forward flow by 4D flow -aortic forward flow by 4D flow). For all cases and MR types, 520 MR volumes were recorded by these 4 methods for intra−/inter-observer tests. Results: In primary MR, MR MVAV and MR LVRV were comparable to MR Standard (P > 0.05). MR Jet resulted in significantly higher MR volumes when compared to MR Standard (P < 0.05) In secondary MR and MVR cases, all methods were comparable. In intra-observer tests, MR MVAV demonstrated least bias with best limits of agreement (bias = −0.1 ml, −8 ml to 7.8 ml, P = 0.9) and best concordance correlation coefficient (CCC = 0.96, P < 0.01). In interobserver tests, for primary MR and MVR, least bias and highest CCC were observed for MR MVAV . For secondary MR, bias was lowest for MR Jet (−0.1 ml, P_NS). Conclusion: CMR methods of MR quantification demonstrate agreement in secondary MR and MVR. In primary MR, this was not observed. Across all types of MR, MR MVAV quantification demonstrated the highest reproducibility and consistency.