although a pump for self-administration of subcutaneous diuretics has recently been developed. Oral formulations can be self-administered. 2 Cardiac MRI versus other imaging techniques for diagnosing heart failure What is the optimal imaging technique for the diagnosis of heart failure? Why this is important The role of cardiac MRI in the detection and characterisation of several structural and 29 of functional cardiac abnormalities has become well established over the past 25 years. In people with heart failure, cardiac MRI provides reliable and reproducible assessments of the left ventricular (and to a degree the right ventricular) shapes, volumes and ejection fractions. It also provides spatial assessments of the congenital and acquired structural abnormalities of the heart and their interrelationships with the remainder of the heart, as well as functional and haemodynamic assessments of these abnormalities on the heart's performance. Finally, cardiac MRI provides valuable information about the myocardial structure and metabolism, including the presence of inflammation, scarring, fibrosis and infiltration. Cardiac MRI is an expensive form of imaging, and much of this diagnostic information could be provided by less costly non-invasive imaging techniques, chiefly echocardiography. This question aims to find the most clinically and cost-effective imaging technique for the clinical diagnosis of heart failure. 3 The impact of atrial fibrillation on the natriuretic peptide threshold for diagnosing heart failure What is the optimal NT-proBNP threshold for the diagnosis of heart failure in people with atrial fibrillation? Why this is important Atrial fibrillation is a common arrhythmia in the general population, and occurs in 30 to 40% of people with heart failure. Atrial fibrillation can raise the level of serum natriuretic peptides, including NT-proBNP, even in the absence of heart failure. 