From the Guidelines
Two-dimensional echocardiography findings in high output heart failure typically include chamber enlargement, particularly of the left ventricle and left atrium, with normal or increased left ventricular ejection fraction (usually >50-60%). The ventricle often shows hyperdynamic contractility with increased stroke volume. Cardiac output measurements are elevated, generally exceeding 8 L/min or a cardiac index above 4 L/min/m². Doppler studies may reveal increased transmitral E-wave velocity indicating elevated left atrial pressure, and there may be moderate to severe functional mitral regurgitation due to annular dilation. Right-sided chambers can also be dilated with possible tricuspid regurgitation. Pulmonary artery pressures are frequently elevated. The inferior vena cava is often dilated with decreased respiratory variation, suggesting elevated right atrial pressure. These findings differ from typical heart failure with reduced ejection fraction, as the primary issue is volume overload rather than contractile dysfunction. High output heart failure occurs in conditions like severe anemia, arteriovenous fistulas, thyrotoxicosis, beriberi, pregnancy, and certain liver diseases, where the heart cannot meet excessive peripheral circulatory demands despite preserved or enhanced contractility, as suggested by the European Association of Cardiovascular Imaging in their 2017 expert consensus document 1.
Key echocardiography findings to look for in high output heart failure include:
- Chamber enlargement, particularly of the left ventricle and left atrium
- Normal or increased left ventricular ejection fraction (usually >50-60%)
- Hyperdynamic contractility with increased stroke volume
- Elevated cardiac output measurements
- Increased transmitral E-wave velocity indicating elevated left atrial pressure
- Moderate to severe functional mitral regurgitation due to annular dilation
- Dilated right-sided chambers with possible tricuspid regurgitation
- Elevated pulmonary artery pressures
- Dilated inferior vena cava with decreased respiratory variation, suggesting elevated right atrial pressure.
According to the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, two-dimensional echocardiography with Doppler should be performed during initial evaluation of patients presenting with heart failure to assess LVEF, left ventricular size, wall thickness, and valve function 1. However, the more recent European Association of Cardiovascular Imaging expert consensus document provides more specific guidance on the echocardiography findings in high output heart failure 1.
From the Research
2D Echo Findings of High Output Heart Failure
- High output heart failure is characterized by an increase in cardiac output, which can lead to various echocardiographic findings 2.
- Echocardiography is an essential tool in diagnosing and managing heart failure, providing important prognostic information in both heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF) 2, 3.
- In patients with high output heart failure, 2D echo may show:
- Anemia and iron deficiency are common comorbidities in heart failure, and correction of these conditions can lead to improvements in echocardiographic parameters, such as a reduction in preload and left ventricular cavity dimensions, and an improvement in diastolic and load-independent ventricular systolic function parameters 4, 5.
- The use of 2D speckle-tracking echocardiography can provide additional information on left ventricular function, including global longitudinal strain (GLS), which can be useful in assessing systolic function in patients with high output heart failure 2, 6.