What distinguishes High Output Heart Failure (HF) from Congestive Heart Failure (CHF)?

From the Guidelines

High output heart failure is distinct from congestive heart failure due to its underlying mechanism of increased cardiac output that cannot meet the body's demands, often caused by conditions such as anemia, thyrotoxicosis, or liver failure, as opposed to congestive heart failure which results from the heart's inability to pump efficiently. The key difference between high output heart failure and congestive heart failure lies in their pathophysiology, with high output heart failure characterized by an increased volume of blood pumped by the heart, yet still insufficient to meet the body's needs, whereas congestive heart failure is marked by the heart's inability to pump blood efficiently, leading to fluid buildup in the lungs and body tissues 1. Some of the common causes of high output states mimicking heart failure include:

• Anaemia
• Thyrotoxicosis
• Septicaemia
• Liver failure
• Arteriovenous shunts
• Paget’s disease
• Beri-beri In contrast, congestive heart failure often results from the heart's reduced ability to pump blood, leading to fluid retention and congestion in the lungs and systemic circulation. The management of high output heart failure focuses on addressing the underlying cause, such as treating anemia, managing hyperthyroidism, or correcting nutritional deficiencies, whereas congestive heart failure treatment typically involves medications like ACE inhibitors, beta-blockers, diuretics, and aldosterone antagonists to improve heart function and reduce fluid retention 1. Despite their differences, both conditions can present with similar symptoms, such as fatigue, shortness of breath, and edema, making accurate diagnosis crucial for proper treatment.

From the Research

Definition and Characteristics

• High output heart failure (HOHF) is a type of heart failure characterized by an increased cardiac output, unlike congestive heart failure which is typically associated with low cardiac output 2, 3.
• HOHF is often caused by a decrease in systemic vascular resistance, which can lead to a fall in systemic arterial blood pressure and neurohormonal activation, resulting in clinical heart failure 2, 3, 4.

Etiologies

• HOHF can be caused by various diseases, including:
  • Chronic severe anemia 2, 3
  • Large arteriovenous fistula or multiple small arteriovenous shunts 2
  • Severe hepatic or renal disorders 2
  • Sepsis 2, 3
  • Hyperthyroidism 3, 5, 6
  • Beriberi (thiamine deficiency) 5
  • Hypercapnia 3
  • Obesity 4

Treatment and Prognosis

• Treatment of HOHF depends on the underlying etiology and may involve addressing the underlying cause, such as correcting anemia or treating hyperthyroidism 2, 3, 4, 5.
• Conventional heart failure therapies, such as vasodilators and beta-blockers, may not be effective and can even worsen the condition 3.
• Dietary restriction of salt and water, combined with judicious use of diuretics, may be beneficial in some cases 3.
• Prognosis depends on the underlying etiology and the effectiveness of treatment 4.