Paradoxically, activity of the neuroendocrine (body regulation) system, that normally functions to maintain the circulation, can actually worsen heart failure if sustained over time. By following the feedback control it is programmed to, it inadvertently adds strain to the heart. Examine the scenario below where the body is entering the early stages of heart failure due to blocked heart arteries. Click here to see a quick overview of the neuroendocrine system, if necessary.
With time, the heart failure becomes worse and worse. High blood volumes and remodeling increase heart size over time, which further impacts its ability to adequately eject blood. In this way, a system designed to support our heart has caused it to fail when attempting to compensate for heart injury.
Why would the body do this to itself? Consider that the design of this system has evolved in such a way as to protect our body not from heart damage, but from exterior threats. For example, if one suffers an injury where blood is being lost (see example), survival is dependent on maintaining an adequate blood pressure to all vital organs. If blood is lost, then blood pressure in our arteries will drop accordingly. Fluid retention serves to keep high blood volumes to buffer the loss due to injury. By constricting our arteries as shown before, the remaining blood gets mobilized more efficiently to tissues at an adequate pressure. Therefore, possibly the situation shown in the chart isn’t so much an error in design of the neuroendocrine system so much as a misapplication of a control mechanism initiated by initial heart and circulatory impairment.