What is the definition of heart failure?

Heart failure is defined as the inability of the heart to provide adequate cardiac output to meet the body's needs, which aligns with the chosen answer. In heart failure, the heart's pumping ability is compromised, either due to weakened heart muscle (systolic dysfunction) or the heart's inability to fill properly (diastolic dysfunction). This inadequate output can lead to symptoms such as fatigue, shortness of breath, and fluid retention, as the body does not receive sufficient blood and oxygen to function optimally.

While increased heart rate, elevated blood pressure, and increased oxygen consumption can be associated with heart failure or its symptoms, they do not define the condition itself. Increased heart rate can occur as a compensatory mechanism in response to decreased cardiac output. Elevated blood pressure can be a risk factor or secondary condition linked to heart failure but is not a definition of it. Increased oxygen consumption may result from the body's efforts to compensate for decreased efficiency in blood circulation but does not encapsulate the essence of heart failure. Thus, understanding that heart failure centers on the heart's inadequate output is key to grasping its overall implications on health.