High output heart failure is characterized by what?

High output heart failure is characterized by the heart's inability to meet the metabolic needs of the body despite a normal or increased cardiac output. This condition occurs when the demand for blood flow is significantly heightened due to factors such as severe anemia, hyperthyroidism, or sepsis. In these situations, the heart pumps more vigorously, but ultimately, it cannot adequately supply the body's tissues with necessary nutrients and oxygen, leading to symptoms associated with heart failure.

The other options relate to different aspects of heart function or consequences of certain types of heart failure. Excessive fluid retention primarily relates to low output heart failure, where the heart fails to pump effectively. High blood pressure and pulmonary congestion often result from various forms of heart failure but do not specifically characterize high output heart failure itself. In this context, understanding the nature of high output heart failure is crucial for recognizing its causes and implications in clinical practice.