In this study the investigators are aiming to recruit 130 patients with heart failure with preserved ejection fraction who are obese and non-obese to undergo CT and MRI scans, as well as some other investigations including blood tests, to help investigate if having more fat around the heart leads to worse heart function in this condition. This may lead to the development of new treatments aimed at lowering fat levels around the heart and in the rest of the body, specifically to treat HFpEF.

Dysregulated adipose tissue, in particular epicardial adipose tissue (EAT; fat around the heart) may be central to the pathogenesis of obesity related HFpEF. Existing studies have been limited by selection bias (only including obese cohorts), limited cardiac structural and functional assessment (primarily using echocardiography) and lack of corroborating biological data to imply causality. Pilot data demonstrate important associations between EAT with concentric LV remodelling in cohorts at high risk of HFpEF.

Further exploration of the role of EAT and other ectopic fat depots in patients with HFpEF with and without obesity, will provide novel insights into mechanisms by which adiposity drives development of HFpEF.

In this single centre, prospective, case-control study the investigators will recruit participants with HFpEF with and without obesity (total N=130) and utilise multimodality imaging to comprehensively characterise the role of excess adiposity and ectopic fat, specifically EAT, to cardiac dysfunction in HFpEF.

Inclusion Criteria:

• Participant is willing and able to give informed consent for participation in the study.
• Aged ≥18 years old
• Diagnosed with HFpEF by an experienced cardiologist or signs and symptoms of heart failure with a HFA-PEFF score ≥5
• Able to understand written English

Exclusion Criteria:

• LV ejection fraction <45%
• Recovered ejection fraction (previous ejection fraction <40%) unless reduced ejection fraction was in context of tachycardia induced cardiomyopathy (eg atrial fibrillation/atrial flutter)
• Severe primary valvular heart disease
• HFpEF due to infiltrative cardiomyopathy (cardiac amyloidosis or sarcoidosis), genetic hypertrophic cardiomyopathy, restrictive cardiomyopathy/pericardial disease or congenital heart disease
• Known heritable, idiopathic or drug-induced pulmonary arterial hypertension
• Absolute contraindications to cardiac CT or MRI including estimated glomerular filtration rate (eGFR) ≤30ml/min/1.73m2. Patients with MRI-compatible devices are be excluded.
• Women who are pregnant

Males and females, aged ≥18 years old, with a diagnosis of HFpEF with and without obesity.