Decompensated is a condition when decompensated heart failure occurs for two days or more in response to an increase in load, if before that the person felt normal. Myocardial hypoxia and metabolic disorders go hand in hand with the described phenomenon, which can develop even in people without cardiovascular diseases, but with concomitant pathologies, for example, diabetes mellitus. This is usually what doctors write in their discharge notes from the clinic. This diagnosis is made for heart failure of 2, 3-in-4 FC, especially if it was detected for the first time.