AimsThe present analysis from the multicentre prospective Altshock‐2 registry aims to better define clinical features, in‐hospital course, and management of cardiogenic shock complicating acutely decompensated heart failure (ADHF‐CS) as compared with that complicating acute myocardial infarction (AMI‐CS).Methods and resultsAll patients with AMI‐CS or ADHF‐CS enrolled in the Altshock‐2 registry between March 2020 and February 2022 were selected. The primary objective was the characterization of ADHF‐CS patients as compared with AMI‐CS. In‐hospital length of stay and mortality were secondary endpoints. One‐hundred‐ninety of the 238 CS patients enrolled in the aforementioned period were considered for the present analysis: 101 AMI‐CS (80% ST‐elevated myocardial infarction and 20% non‐ST‐elevated myocardial infarction) and 89 ADHF‐CS. As compared with AMI‐CS, ADHF‐CS patients were younger [63 (IQR 59–76) vs. 67 (IQR 54–73) years, P = 0.01], but presented with higher creatinine [1.6 (IQR 1.0–2.6) vs. 1.2 (IQR 1.0–1.4) mg/dL, P < 0.001], bilirubin [1.3 (IQR 0.9–2.3) vs. 0.6 (IQR 0.4–1.1) mg/dL, P = 0.01], and central venous pressure values [14 mmHg (IQR 8–12) vs. 10 mmHg (IQR 7–14),P = 0.01]. Norepinephrine was the most common catecholamine used in AMI‐CS (79.3%), whereas epinephrine was used more commonly in ADHF‐CS (65.5%); 75.8% vs. 46.6% received a temporary mechanical support in AMI‐CS and ADHF‐CS, respectively (P < 0.001). Length of hospital stay was longer in the latter [28 (IQR 13–48) vs. 17 (IQR 9–29) days, P = 0.001]. Heart replacement therapies were more frequently used in the ADHF‐CS group (heart transplantation 13.5% vs. 0% and left ventricular assist device 11% vs. 2%, P < 0.01 and 0.01, respectively). In‐hospital mortality was 41.1% (38.6% AMI‐CS vs. 43.8% ADHF‐CS, P = 0.5).ConclusionsADHF‐CS is characterized by a higher prevalence of end‐organ and biventricular dysfunction at presentation, a longer hospital length of stay, and higher need of heart replacement therapies when compared with AMI‐CS. In‐hospital mortality was similar between the two aetiologies. Our data warrant development of new management protocols focused on CS aetiology.