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Introduction: Cardiac magnetic resonance (CMR) has excellent diagnostic accuracy in patients with suspected myocarditis. The role of CMR-assessed strain (using feature tracking; FT) in myocarditis assessment is evolving. Methods: We included consecutive patients with clinical suspicion of acute myocarditis referred for CMR between 2012 and 2017. We compared patients with confirmed diagnosis of acute myocarditis (n=59, age 40±15, 59% male), patients in whom myocarditis was excluded (n=28, age 40±13, 55% male), and age- and gender-matched controls with normal CMR (n=59). We quantified myocardial mechanics using FT-strains and T1 mapping using dedicated software. Investigators were blinded to clinical data. The primary endpoint was MACE: death, cardiac rehospitalization, or implantation of ICD-CRT-LVAD. Results: Patients with myocarditis exhibited more impaired longitudinal strain (FT-LS) than those without (14.8±5.6 vs 21.9±2.9 ms, p<0.01) or controls (14.8±5.6 vs 23.4±2.7 ms, p<0.01). FT-LS was not different between the latter two groups. Myocarditis patients in the worse tertile of LS showed more severity of myocarditis than those in the best tertile (Table): longer hospitalization, more use of diuretic and inotropic drugs, more severe cardiac damage (as reflected by higher peak TnI and BNP, and shorter post-contrast T1 time), worse baseline systolic and diastolic function, and worse recovery of LVEF at follow up. Over a mean follow up of 30±15 months, 23 patients reached the primary endpoint. FT-LS >-11.5% was predictive of the primary endpoint (sensitivity 78%, specificity 90%, area under the curve 0.82). In multivariate analysis, LS was an independent predictor of MACE even after adjusting for initial LVEF and TnI (HR 3.38, [2.05-4.84], p<0.01). Conclusions: CMR-derived LS using FT is an independent predictor of adverse cardiovascular outcome, and is thus an effective tool to evaluate the severity and prognosis of patients with acute myocarditis. [ABSTRACT FROM AUTHOR]

Background: Large clinical trials established the benefits of sodium-glucose cotransporter 2 inhibitors in patients with diabetes and with heart failure with reduced ejection fraction (HFrEF). The early and significant improvement in clinical outcomes is likely explained by effects beyond a reduction in hyperglycemia.Objectives: The purpose of this study was to assess the effect of empagliflozin on left ventricular (LV) function and volumes, functional capacity, and quality of life (QoL) in nondiabetic HFrEF patients.Methods: In this double-blind, placebo-controlled trial, nondiabetic HFrEF patients (n = 84) were randomized to empagliflozin 10 mg daily or placebo for 6 months. The primary endpoint was change in LV end-diastolic and -systolic volume assessed by cardiac magnetic resonance. Secondary endpoints included changes in LV mass, LV ejection fraction, peak oxygen consumption in the cardiopulmonary exercise test, 6-min walk test, and quality of life.Results: Empagliflozin was associated with a significant reduction of LV end-diastolic volume (-25.1 ± 26.0 ml vs. -1.5 ± 25.4 ml for empagliflozin vs. placebo, respectively; p < 0.001) and LV end-systolic volume (-26.6 ± 20.5 ml vs. -0.5 ± 21.9 ml for empagliflozin vs. placebo; p < 0.001). Empagliflozin was associated with reductions in LV mass (-17.8 ± 31.9 g vs. 4.1 ± 13.4 g, for empagliflozin vs. placebo, respectively; p < 0.001) and LV sphericity, and improvements in LV ejection fraction (6.0 ± 4.2 vs. -0.1 ± 3.9; p < 0.001). Patients who received empagliflozin had significant improvements in peak O2 consumption (1.1 ± 2.6 ml/min/kg vs. -0.5 ± 1.9 ml/min/kg for empagliflozin vs. placebo, respectively; p = 0.017), oxygen uptake efficiency slope (111 ± 267 vs. -145 ± 318; p < 0.001), as well as in 6-min walk test (81 ± 64 m vs. -35 ± 68 m; p < 0.001) and quality of life (Kansas City Cardiomyopathy Questionnaire-12: 21 ± 18 vs. 2 ± 15; p < 0.001).Conclusions: Empagliflozin administration to nondiabetic HFrEF patients significantly improves LV volumes, LV mass, LV systolic function, functional capacity, and quality of life when compared with placebo. Our observations strongly support a role for sodium-glucose cotransporter 2 inhibitors in the treatment of HFrEF patients independently of their glycemic status. (Are the "Cardiac Benefits" of Empagliflozin Independent of Its Hypoglycemic Activity? [ATRU-4] [EMPA-TROPISM]; NCT03485222). [ABSTRACT FROM AUTHOR]

Background: Empagliflozin cardiac benefits in the EMPA-REG OUTCOME (Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients) trial cannot be explained exclusively by its antihyperglycemic activity.Objectives: The hypothesis was that empagliflozin's cardiac benefits are mediated by switching myocardial fuel metabolism away from glucose toward ketone bodies (KB), which improves myocardial energy production.Methods: Heart failure was induced in nondiabetic pigs (n = 14) by 2-h balloon occlusion of the proximal left anterior descending artery. Animals were randomized to empagliflozin or placebo for 2 months. Animals were evaluated with cardiac magnetic resonance imaging and 3-dimensional echocardiography. Myocardial metabolite consumption was analyzed by simultaneous blood sampling from coronary artery and coronary sinus. Myocardial samples were obtained for molecular evaluation. Nonmyocardial infarction animals served as comparison.Results: Despite similar initial ischemic myocardial injury in both groups, the empagliflozin group showed amelioration of adverse remodeling at 2 months (lower left ventricular [LV] mass, reduced LV dilatation, less LV sphericity) versus the control group. LV systolic function (LV ejection fraction and echocardiography-derived strains) was improved, as was neurohormonal activation. Compared with nonmyocardial infarction, control animals increased myocardial glucose consumption mainly through anaerobic glycolysis while reducing utilization of free fatty acid (FFA) and branched-chain amino acid (BCAA). Empagliflozin-treated pigs did not consume glucose (reduction in myocardial glucose uptake, and glucose-related enzymes) but instead switched toward utilization of KB, FFA, and BCAA (increased myocardial uptake of these 3 metabolites, and enhanced expression/activity of the enzymes implicated in the metabolism of KB/FFA/BCAA). Empagliflozin increased myocardial ATP content and enhanced myocardial work efficiency.Conclusions: Empagliflozin ameliorates adverse cardiac remodeling and heart failure in a nondiabetic porcine model. Empagliflozin switches myocardial fuel utilization away from glucose toward KB, FFA, and BCAA, thereby improving myocardial energetics, enhancing LV systolic function, and ameliorating adverse LV remodeling. [ABSTRACT FROM AUTHOR]

Introduction: In vitro, ketone bodies (KB) are the most energetically efficient fuel for myocardium. Ex vivo, KB infusion in the perfusion medium of working rat hearts increases the heat of combustion (produced energy) by 31%. However, there is no report about the in vivo effects of KB on LV function. We hypothesized that KB infusion in HFREF would improve energy production and thus LV systolic function. Methods: HFREF was induced in 15 pigs by 2-hour balloon occlusion of LAD: proximal LAD (n=8, severe HREF) and mid LAD (n=7, moderate HFREF). At 2 months, LV systolic function was evaluated during saline infusion and during infusion of the KB β-hydroxybutyrate. Severe HFREF animals underwent cardiac MRI for baseline LVEF, feature tracking strains, and contractile reserve (ΔLVEF under dobutamine 5μg/kg/min). Moderate HFREF pigs underwent invasive hemodynamic assessment (dP/dt) and 3D-echocadiography (3D-LVEF and 3D-strains). Simultaneous sampling from coronary artery and coronary sinus was performed to measure myocardial fuel consumption. Results: Proximal and mid LAD occlusion resulted in severe and moderate LV systolic dysfunction, respectively. In the severe HFREF, ketone infusion improved baseline LVEF, feature-tracking strains (both longitudinal and circumferencial strain), and contractile reserve. In the moderate HFREF, ketone infusion improved 3D-LVEF, 3D-strains and dP/dt (Table). Ketone infusion switched myocardial metabolism from glucose to ketone consumption. Conclusions: Continuous infusion of the KB hydroxybutyrate improves LV systolic function independent of LV systolic dysfunction severity via a shift in myocardial fuel metabolism away from glucose oxidation (energy inefficient) toward a more energy-efficient fuel like KB. This effect can explain the mechanism of action of the benefits of SGLT2 inhibitors in heart failure, as empagliflozin-induced mild kyperketonemia may increase LV systolic function and thus improve patient outcomes. [ABSTRACT FROM AUTHOR]