From the Research
High output cardiac failure is defined as a clinical syndrome where the heart fails despite maintaining a cardiac output that is above the normal range, specifically characterized by a cardiac output exceeding 8 L/min or a cardiac index greater than 4 L/min/m². This condition occurs when the heart cannot meet the body's increased metabolic demands despite pumping more blood than normal. The increased output places excessive strain on the heart, eventually leading to cardiac dysfunction and failure.
Key Characteristics
- Cardiac output: exceeding 8 L/min
- Cardiac index: greater than 4 L/min/m²
- Normal cardiac output: typically 4-8 L/min
- Normal cardiac index: 2.5-4 L/min/m² Common causes include severe anemia, hyperthyroidism, arteriovenous fistulas, beriberi, pregnancy, and certain liver diseases, as noted in studies 1, 2, 3, 4. The pathophysiology involves peripheral vasodilation and decreased systemic vascular resistance, which increases venous return to the heart and forces it to pump more vigorously 3, 4.
Treatment Considerations
Treatment focuses on addressing the underlying cause rather than the standard heart failure medications, as traditional heart failure therapies may worsen the condition by further reducing cardiac output 2, 3, 4. It is essential to recognize that many aetiologies of high-output cardiac failure are potentially curable, and prompt recognition of this condition and proper treatment may lead to better outcomes 4.