DANHEART (H-HeFT and Met-HeFT)

Inclusion Criteria: General inclusion criteria for both H-HeFT and Met-HeFT * Patients with chronic heart failure * NYHA-class II, III or IV * LVEF \</= 40% within 12 months prior to screening. The echocardiography should (i) be performed after uptitration in heart failure medication and (ii) LVEF from the most recently performed echocardiographic study should be used and (iii) LVEF must not be measured during rapid atrial fibrillation, i.e. heart rate \>110/min) and (iiii) the echocardiography should be performed at least 3 months after CRT-implantation. * Patients should be uptitrated to recommended or maximally tolerated dose of ACE-I/ARB/ARNI (unless contraindicated) and beta-blocker (unless contraindicated). If indicated, an aldosterone receptor antagonist should be given (unless contraindicated). * A CRT device should be implanted, if indicated and accepted by the patient and patients with a CRT device should be treated for \> 3 months. * Implantation of an ICD unit should be planned or already done, if indicated and accepted by the patient. The patient can be included in the study before a planned ICD implantation has been performed. * Informed consent Specific inclusion criteria for only H-HeFT: * Systolic blood pressure ≥100 mmHg * NT-proBNP \> 350 pg/ml or BNP \> 80 pg/ml (in patients treated with ARNI, NT-proBNP must be used) Specific inclusion criteria for only Met-HeFT: Patients must have a diagnosis of type 2 diabetes or insulin resistance or diabetes risk…