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Background: Heart transplantation (HTx) after donation after circulatory death (DCD) is an expanding practice but is associated with increased warm ischemic time. The impact of DCD HTx on cardiac mechanics and myocardial fibrosis has not been reported. We aimed to compare cardiac mechanics and myocardial fibrosis using cardiovascular magnetic resonance (CMR) imaging in donation after brain death (DBD) and DCD HTx recipients and healthy controls., Methods and Results: Consecutive HTx recipients between March 2015 and March 2021 who underwent routine surveillance CMR imaging were included. Cardiac mechanics were assessed using CMR feature tracking to compute global longitudinal strain, global circumferential strain, and right ventricular free-wall longitudinal myocardial strain. Fibrosis was assessed using late gadolinium enhancement imaging and estimation of extracellular volume. There were 82 (DBD n = 42, DCD n = 40) HTx recipients (aged 53 years, interquartile range 41-59 years, 24% female) who underwent CMR imaging at median of 9 months (interquartile range 6-14 months) after transplantation. HTx recipients had increased extracellular volume (29.7 ± 3.6%) compared with normal ranges (25.9%, interquartile range 25.4-26.5). Myocardial strain was impaired after transplantation compared with controls (global longitudinal strain -12.6 ± 3.1% vs -17.2 ± 1.8%, P < .0001; global circumferential strain -16.9 ± 3.1% vs -19.2 ± 2.0%, P = .002; right ventricular free-wall longitudinal strain -15.7 ± 4.5% vs -21.6 ± 4.7%, P < .0001). There were no differences in fibrosis burden (extracellular volume 30.6 ± 4.4% vs 29.2 ± 3.2%; P = .39) or cardiac mechanics (global longitudinal strain -13.1 ± 3.0% vs -12.1 ± 3.1%, P = .14; global circumferential strain -17.3 ± 2.9% vs -16.6 ± 3.1%, P = .27; right ventricular free-wall longitudinal strain -15.9 ± 4.9% vs -15.5 ± 4.1%, P = .71) between DCD and DBD HTx., Conclusions: HTx recipients have impaired cardiac mechanics compared with controls, with increased myocardial fibrosis. There were no differences in early CMR imaging characteristics between DBD and DCD heart transplants, providing further evidence that DCD and DBD HTx outcomes are comparable., Competing Interests: Disclosures Royal Papworth Hospital has received grants from the European Society of Organ Transplantation, The Freemasons Grand Charity, the Masonic Samaritan Fund, the Evelyn Trust, RPH Charity, NHSBT, and the Gledhill Fellowship to fund the early DCD research programme. J.R.W.M. is supported by the NIHR Cambridge Biomedical Research Centre (BRC-1215-20014). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care., (Crown Copyright © 2022. Published by Elsevier Inc. All rights reserved.)

Heart failure with preserved ejection fraction (HFpEF) is recognised as an increasingly prevalent, morbid and burdensome condition with a poor outlook. Recent advances in both the understanding of HFpEF and the technological ability to image cardiac function and metabolism in humans have simultaneously shone a light on the molecular basis of this complex condition of diastolic dysfunction, and the inflammatory and metabolic changes that are associated with it, typically in the context of a complex patient. This review both makes the case for an integrated assessment of the condition, and highlights that metabolic alteration may be a measurable outcome for novel targeted forms of medical therapy. It furthermore highlights how recent technological advancements and advanced medical imaging techniques have enabled the characterisation of the metabolism and function of HFpEF within patients, at rest and during exercise., (© 2022. The Author(s).)

Background The sympathetic cotransmitter, neuropeptide Y (NPY), is released into the coronary sinus during ST-segment-elevation myocardial infarction and can constrict the coronary microvasculature. We sought to establish whether peripheral venous (PV) NPY levels, which are easy to obtain and measure, are associated with microvascular obstruction, myocardial recovery, and prognosis. Methods and Results NPY levels were measured immediately after primary percutaneous coronary intervention and compared with angiographic and cardiovascular magnetic resonance indexes of microvascular function. Patients were prospectively followed up for 6.4 (interquartile range, 4.1-8.0) years. PV (n=163) and coronary sinus (n=68) NPY levels were significantly correlated ( r =0.92; P <0.001) and associated with multiple coronary and imaging parameters of microvascular function and infarct size (such as coronary flow reserve, acute myocardial edema, left ventricular ejection fraction, and late gadolinium enhancement 6 months later). We therefore assessed the prognostic value of PV NPY during follow-up, where 34 patients (20.7%) developed heart failure or died. Kaplan-Meier survival analysis demonstrated that high PV NPY levels (>21.4 pg/mL by binary recursive partitioning) were associated with increased incidence of heart failure and mortality (hazard ratio, 3.49 [95% CI, 1.65-7.4]; P <0.001). This relationship was maintained after adjustment for age, cardiovascular risk factors, and previous myocardial infarction. Conclusions Both PV and coronary sinus NPY levels correlate with microvascular function and infarct size after ST-segment-elevation myocardial infarction. PV NPY levels are associated with the subsequent development of heart failure or mortality and may therefore be a useful prognostic marker. Further research is required to validate these findings.