Pathophysiology of Heart Failure

Abstract

Heart failure is a clinical syndrome initiated by abnormal function of the heart. Until recently our understanding of this condition has centered on various pathological insults to the heart that lead to abnormal function, usually in the form of contractile dysfunction. One of the earliest terms used to describe heart failure syndrome was “hydrops,” which has its origins in the observation that salt and water retention was a common feature of the condition. Despite this obvious systemic manifestation, heart failure was still considered primarily a disease of the heart. In recent years advances have been made in our understanding of the pathophysiology of heart failure; key to these has been the realization that heart failure is a multisystem disorder in which abnormalities of the heart, vasculature, skeletal muscle, and kidneys all combine with various neurohormonal derangements to produce the heart failure syndrome. Of particular importance has been the emerging concept that many of the compensatory mechanisms designed to overcome the initial insult to the heart are the very same processes that paradoxically set in motion a variety of detrimental consequences for cardiac function, gradually worsening the heart failure syndrome further. Our increasing understanding of these concepts has resulted in a rapid advancement in drug development and many new therapeutic targets continue to emerge. In this chapter we summarize the pathophysiology of heart failure, beginning with the specific insults that initiate heart failure and continuing with a discussion of the body’s responses to such insults, and how compensatory mechanisms ultimately cause further deterioration in cardiac function.