There has been a rapid expansion in the number of cardiac magnetic resonance imaging (CMR) tests performed in the UK from 20597 in 2008 to 38485 in 2010 and yet there are no clear recommendations about its use. The role of cMRI in the diagnosis of chronic heart failure, in relation to other imaging techniques is unclear as is its place in the diagnostic pathway for patients with heart failure. This question addressed the clinical efficacy and cost effectiveness of cMRI compared to standard imaging technologies and whether all patients suspected of heart failure should undergo cMRI imaging or should it be used selectively in some patients? 5.5.2 Review question: In people with heart failure what is the clinical and cost effectiveness of cardiac MRI followed by the appropriate patient pathway? For full details see review protocol in Appendix A. Table 26: PICO characteristics of review question Population All people with HF in a community or outpatient setting. Intervention/Co mparators Echocardiography plus routine cardiac MRI Echocardiography plus selective cardiac MRI Echocardiography alone (all interventions will be compared against each other) Outcomes CRITICAL: All-cause mortality (time to event) Health-related quality of life at 12 months (continuous) Unplanned hospitalisation (total number of events (rate ratio)) IMPORTANT: Adverse events related to test (non-specific fibrosis in the presence of renal dysfunction) Reclassification of specific HF aetiology (including ability to classify previous unclassified patients) Change in management HF medication use HF advanced therapy use, including disease specific therapies Repeat testing / additional testing Study design RCTs Chronic Heart Failure Diagnosing heart failure NICE 2018. All rights reserved. Subject to Notice of rights. ISBN: 978-1-4731-3093-7 Systematic reviews of RCTs 5.5.3 Clinical evidence No relevant clinical studies comparing the effectiveness of different cardiac MRI (cMRI) imaging modalities with echocardiography (echo) were identified. 