Eligible patients with severe cardiogenic shock will be randomized to one of the two arms: immediate ECMO therapy or early conservative therapy. In the invasive group, veno-arterial ECMO will be implanted according to the local practice with flow settings to ensure sufficient tissue perfusion. With the exception of ECMO implantation in the invasive group, all other diagnostic and therapeutic procedures will be done according to the current standard of care at the tertiary cardiovascular center, including other cardiovascular interventions (i.e. percutaneous coronary intervention or cardiac surgery). Implantation of other mechanical support devices including ECMO in the primary conservative group is allowed in the case of shock progression with rise of serum lactate by 3 mmol/L in comparison with the lowest value during the past 24 hours. Follow-up include visits at 30 days, 6 moths and 12 months.

Inclusion Criteria:

Patients must fulfil criteria for rapidly deteriorating (A) or severe (B) cardiogenic shock:

A. Rapidly deteriorating cardiogenic shock is defined as progressive hemodynamic instability necessitating repeated bolus administration of vasopressors to maintain mean arterial pressure > 50 mmHg + impaired left ventricle systolic function (Left ventricle ejection fraction (LVEF) < 35% or LVEF 35-55% in case of severe mitral regurgitation or aortic stenosis) or

B. In severe cardiogenic shock all following criteria should be met:

1. Hemodynamic:

   Cardiac Index (CI) < 2.2 L/min/m2 + norepinephrine dose > 0.1 μg/kg/min + dobutamin dose > 5 μg/kg/min or Systolic blood pressure < 100 mmHg + norepinephrine dose > 0.2 μg/kg/min + dobutamin dose > 5 μg/kg/min + (LVEF < 35% or LVEF 35-55% + severe mitral regurgitation or aortic stenosis)

2. Metabolic:

   Lactate - two consecutive values ≥ 3 mmol/L (with at least 30 min between samples), with non-decreasing trend on steady doses of inotropes and/or vasopressors or SvO2 - two consecutive values < 50% (with at least 30 min between measurements), with non-increasing trend on steady doses of inotropes and/or vasopressors

3. Hypovolemia must be excluded:

Central venous pressure > 7 mmHg or pulmonary capillary wedge pressure > 12 mmHg

Exclusion Criteria:

1. Age < 18 years
2. Life expectancy lower than 1 year
3. High suspicion of pulmonary emboli or cardiac tamponade as a cause of shock
4. Significant bradycardia or tachycardia which might be responsible for hemodynamic instability and not treated by pacing or cardioversion
5. Cardiac arrest survivors remaining comatose
6. Hypertrophic obstructive cardiomyopathy
7. Peripheral artery disease disabling insertion of outflow cannula to femoral artery
8. Moderate to severe aortic regurgitation
9. Aortic dissection
10. Uncontrolled bleeding or TIMI major bleeding within last 6 months
11. Known encephalopathy