Background: Small studies have suggested that high-intensity interval training (HIIT) is superior to moderate continuous training (MCT) in reversing cardiac remodeling and increasing aerobic capacity in patients with heart failure with reduced ejection fraction. The present multicenter trial compared 12 weeks of supervised interventions of HIIT, MCT, or a recommendation of regular exercise (RRE). Methods: Two hundred sixty-one patients with left ventricular ejection fraction ≤35% and New York Heart Association class II to III were randomly assigned to HIIT at 90% to 95% of maximal heart rate, MCT at 60% to 70% of maximal heart rate, or RRE. Thereafter, patients were encouraged to continue exercising on their own. Clinical assessments were performed at baseline, after the intervention, and at follow-up after 52 weeks. Primary end point was a between-group comparison of change in left ventricular end-diastolic diameter from baseline to 12 weeks. Results: Groups did not differ in age (median, 60 years), sex (19% women), ischemic pathogenesis (59%), or medication. Change in left ventricular end-diastolic diameter from baseline to 12 weeks was not different between HIIT and MCT ( P =0.45); left ventricular end-diastolic diameter changes compared with RRE were −2.8 mm (−5.2 to −0.4 mm; P =0.02) in HIIT and −1.2 mm (−3.6 to 1.2 mm; P =0.34) in MCT. There was also no difference between HIIT and MCT in peak oxygen uptake ( P =0.70), but both were superior to RRE. However, none of these changes was maintained at follow-up after 52 weeks. Serious adverse events were not statistically different during supervised intervention or at follow-up at 52 weeks (HIIT, 39%; MCT, 25%; RRE, 34%; P =0.16). Training records showed that 51% of patients exercised below prescribed target during supervised HIIT and 80% above target in MCT. Conclusions: HIIT was not superior to MCT in changing left ventricular remodeling or aerobic capacity, and its feasibility remains unresolved in patients with heart failure. Clinical Trial Registration: URL: http://www.clinicaltrials.gov . Unique identifier: NCT00917046.

Quiz Ref ID Heart failure (HF) affects more than 2% of the global adult population and resulted in 809 000 hospitalizations in the US in 2016.¹ An analysis of 28 820 patients from different cohort studies² (inclusion between 1979 and 2002; followed for up to 15 years) demonstrated that approximately 50% of patients with incident HF had a preserved ejection fraction (HFpEF) and based on data from community surveillance in 4 US communities (2005 to 2009), 47% of hospitalizations for incident HF events were due to HFpEF.³ The prevalence of HFpEF is projected to further increase, primarily driven by an aging population.¹ Additional risk factors include hypertension, previous myocardial infarction, diabetes, obesity, and sedentary lifestyle.^2,4

In primary prevention, regular physical activity decreases the incidence of cardiovascular disease. At the endothelial level, this decreased incidence was attributed to higher expression and phosphorylation of the endothelial isoform of NO synthase, which results in a more effective radical

Rationale:: High-density lipoprotein (HDL) exerts endothelial-protective effects via stimulation of endothelial cell (EC) nitric oxide (NO) production. This function is impaired in patients with cardiovascular disease. Protective effects of exercise training (ET) on endothelial function have been demonstrated. Objective:: This study was performed to evaluate the impact of ET on HDL-mediated protective effects and the respective molecular pathways in patients with chronic heart failure (CHF). Methods and Results:: HDL was isolated from 16 healthy controls (HDL _healthy ) and 16 patients with CHF-NYHA-III (HDL _NYHA-IIIb ) before and after ET, as well as from 8 patients with CHF-NYHA-II (HDL _NYHA-II ). ECs were incubated with HDL, and phosphorylation of eNOS-Ser ¹¹⁷⁷ , eNOS-Thr ⁴⁹⁵ , PKC-βII-Ser ⁶⁶⁰ , and p70S6K-Ser ⁴¹¹ was evaluated. HDL-bound malondialdehyde and HDL-induced NO production by EC were quantified. Endothelial function was assessed by flow-mediated dilatation. The proteome of HDL particles was profiled by shotgun LC-MS/MS. Incubation of EC with HDL _NYHA-IIIb triggered a lower stimulation of phosphorylation at eNOS-Ser ¹¹⁷⁷ and a higher phosphorylation at eNOS-Thr ⁴⁹⁵ when compared with HDL _healthy . This was associated with lower NO production of EC. In addition, an elevated activation of p70S6K, PKC-βII by HDL _NYHA-IIIb , and a higher amount of malondialdehyde bound to HDL _NYHA-IIIb compared with HDL _healthy was measured. In healthy individuals, ET had no effect on HDL function, whereas ET of CHF-NYHA-IIIb significantly improved HDL function. A correlation between changes in HDL-induced NO production and flow-mediated dilatation improvement by ET was evident. Conclusions:: These results demonstrate that HDL function is impaired in CHF and that ET improved the HDL-mediated vascular effects. This may be one mechanism how ET exerts beneficial effects in CHF.

BACKGROUND: Clinical studies demonstrated beneficial effects of sodium-glucose-transporter 2 inhibitors on the risk of cardiovascular death in patients with heart failure with preserved ejection fraction (HFpEF). However, underlying processes for cardioprotection remain unclear. The present study focused on the impact of empagliflozin (Empa) on myocardial function in a rat model with established HFpEF and analyzed underlying molecular mechanisms. METHODS: Obese ZSF1 (Zucker fatty and spontaneously hypertensive) rats were randomized to standard care (HFpEF, n=18) or Empa (HFpEF/Empa, n=18). ZSF1 lean rats (con, n=18) served as healthy controls. Echocardiography was performed at baseline and after 4 and 8 weeks, respectively. After 8 weeks of treatment, hemodynamics were measured invasively, mitochondrial function was assessed and myocardial tissue was collected for either molecular and histological analyses or transmission electron microscopy. RESULTS: In HFpEF Empa significantly improved diastolic function (E/é: con: 17.5±2.8; HFpEF: 24.4±4.6; P <0.001 versus con; HFpEF/Empa: 19.4±3.2; P <0.001 versus HFpEF). This was accompanied by improved hemodynamics and calcium handling and by reduced inflammation, hypertrophy, and fibrosis. Proteomic analysis demonstrated major changes in proteins involved in mitochondrial oxidative phosphorylation. Cardiac mitochondrial respiration was significantly impaired in HFpEF but restored by Empa (V _max complex IV: con: 0.18±0.07 mmol O ₂ /s/mg; HFpEF: 0.13±0.05 mmol O ₂ /s/mg; P <0.041 versus con; HFpEF/Empa: 0.21±0.05 mmol O ₂ /s/mg; P =0.012 versus HFpEF) without alterations of mitochondrial content. The expression of cardiolipin, an essential stability/functionality-mediating phospholipid of the respiratory chain, was significantly decreased in HFpEF but reverted by Empa (con: 15.9±1.7 nmol/mg protein; HFpEF: 12.5±1.8 nmol/mg protein; P =0.002 versus con; HFpEF/Empa: 14.5±1.8 nmol/mg protein; P =0.03 versus HFpEF). Transmission electron microscopy revealed a reduced size of mitochondria in HFpEF, which was restored by Empa. CONCLUSIONS: The study demonstrates beneficial effects of Empa on diastolic function, hemodynamics, inflammation, and cardiac remodeling in a rat model of HFpEF. These effects were mediated by improved mitochondrial respiratory capacity due to modulated cardiolipin and improved calcium handling.