This is a randomized 1:1 blinded study that evaluate in acute left heart failure-cardiogenic shock patients if ivabradine treatment can reduce pulmonary wedge pressure, without inducing a significant or relevant reduction in cardiac output or increasing the risk of arterial hypotension and with the benefit of allowing a faster titration of heart failure drugs.

Inclusion Criteria:

• Patients aged ≥ 18 years, with acute heart failure due to left ventricular systolic dysfunction (LVEF ≤ 40%) in sinus rhythm, baseline HR ≥ 90 bpm, with signs of low peripheral perfusion with indication for intravenous inotropic treatment (catecholamines: dobutamine , adrenaline, dopamine or noradrenaline) and admitted to the Cardiological Intensive Care Unit.
• Pharmacological treatment and stable hemodynamic situation in the 4 hours before inclusion.
• Pulmonary wedge pressure ≥ 18 mm Hg and systolic blood pressure > 90 mm Hg.
• Patient's signature on the consent form.

Exclusion Criteria:

• Previous treatment with ivabradine (< 48 hours).
• Known hypersensitivity to ivabradine.
• Cardiac rhythm different from sinus rhythm.
• Unstable cardiac rhythm due to paroxysmal atrial fibrillation or atrial flutter, very frequent ventricular or supraventricular premature beats, ventricular tachycardia, 2nd or 3rd degree atrioventricular (AV) block.
• Severe chronic renal failure (estimated glomerular filtration rate ≤15 ml / min) or on chronic treatment with dialysis.
• QT interval higher than 450 ms.
• Sepsis as a probable mechanism of tachycardia and hypotension.
• Need for urgent cardiac surgery, planned within 72 hours of possible inclusion.
• Severe aortic stenosis or severe valvular disease that requires surgical correction.
• Patient must not have received an IV bolus of furosemide immediately before the baseline hemodynamic assessment.
• Severe hepatic insufficiency.
• Patient must not be participating in another clinical trial.
• Concomitant use of potent CYP3A4 inhibitors.
• Acute anemia or hypovolemia uncorrected.
• Pregnancy.