Cardiogenic shock a serious complication of a heart attack (myocardial infarction). Despite rapid invasive treatment, circulatory support using positive inotropes and mechanical support with intra-aortic balloon counterpulsation (IABP), and evaluation of several new treatments during the last decade, the mortality in patients with cardiogenic shock still exceeds 50%. An alternative to current management is restoration of the volume of blood pumped by the heart (cardiac output) using a ventricular assist device. In the acute setting this is difficult but can be done using the Impella device which is a catheter-based, axial flow pump that pumps blood directly from the left ventricle into the circulation thereby restoring blood flow to the failing organs. In 2012 a more powerful Impella has been introduced that is able to deliver 3.5l/min (approximately 75% of a normal cardiac output). The hypothesis of the current study is to reduce mortality and morbidity of patients with cardiogenic shock using the Impella CP. The study will be carried out as a randomized multicenter study where eligible patients will be randomized to receive conventional circulatory support or support with the Impella device and inotropic support if needed. A total of 360 patients are planned to be enrolled, and the primary endpoint will be death.

Inclusion Criteria:

1. ST segment elevation myocardial infarction of less than 36 hours' duration, confirmed by new onset ST-segment elevation, or emergency angiography demonstrating acute occlusion of coronary artery, and

2. Cardiogenic shock of less than 24 hours' duration, confirmed by:

   • peripheral signs of tissue hypoperfusion (arterial blood lactate ≥2.5mmol/l and/or SvO2 <55% with a normal PaO2) and
   • systolic blood pressure less than 100mmHg and/or need for vasopressor therapy (dopamine/ norepinephrine or epinephrine), and

3. Left ventricular ejection fraction of less than 45% visually estimated or by wall motion score index >1,6.

Exclusion Criteria:

1. Other causes of shock (hypovolemia, hemorrhage, sepsis, pulmonary embolism or anaphylaxis).
2. Shock due to mechanical complication to myocardial infarction (papillary muscle rupture, rupture of the ventricular septum or rupture of free wall).
3. Severe aorta valve regurgitation/stenosis.
4. Predominant right ventricular failure.
5. Out of hospital cardiac arrest with persistent Glasgow coma scale <8 after return of spontaneous circulation.
6. Shock duration>24 hours.
7. Known heparin intolerance.
8. Already established mechanical circulatory support
9. Do not resuscitate wish.