A Research Study Comparing CDR132L With Placebo on the Structure and Function of the Heart in People With Heart Failure With Reduced/Mildly Reduced Ejection Fraction and Left Ventricular Hypertrophy

Inclusion Criteria

• •Age 40-84 years (both inclusive) at the time of signing the informed consent.
• •Documented symptomatic heart failure (HF) diagnosed greater than or equal to (≥) 180 days prior to screening with at least weekly need for oral diuretic treatment, and New York Heart Association class II-III at screening.
• •Clinically stable and on optimized doses and unchanged drug classes of guideline-directed HF therapy ≥ 45 days prior to randomisation.
• •Left ventricular ejection fraction (LVEF) less than (\<) 50 percent (%) as assessed by echocardiography at screening, measured by central laboratory.
• •Left ventricular hypertrophy or left ventricular dilatation assessed by echocardiography at screening measured by central laboratory with any of the following:
• •1. LVMi greater than (\>)88 g/m\^2 for female participants and \>102 g/m\^2 for male participants using the truncated ellipsoid method.
• •2. LVMi \>95 g/m\^2 for female participants and \>115 g/m\^2 for male participants, using the linear method (cube formula).
• •3. Left ventricular end-diastolic diameter indexed to body surface area (LVEDDi) \>3.1 cm/m\^2 for female participants and \>3.0 cm/m\^2 for male participants.
• •Body mass index 18.5-40 kilogram per meter square (kg/m\^2) (both inclusive) and body weight less than or equal to (≤) 140 kilogram (kg). Body mass index is calculated in the electronic case report form based on height and body weight at the screening visit (visit 1).
• •N-terminal pro B-type natriuretic peptide (NT-proBNP) ≥ 300 picograms per milliliter (pg/mL); NT-proBNP ≥600 pg/mL if atrial fibrillation/flutter is present at time of screening, measured by central laboratory.