What characterizes cardiac ejection fraction in various cardiac conditions?

From the Guidelines

The correct answer is C. It is decreased in mitral incompetence is incorrect, instead, it is increased in conditions with left-to-right shunts like ventricular septal defects, but among the options provided, the most accurate statement related to the question is that ejection fraction is typically increased in mitral incompetence (regurgitation). Cardiac ejection fraction, which measures the percentage of blood ejected from the ventricle with each contraction, is typically elevated in conditions with mitral regurgitation. This occurs because some blood is ejected back into the left atrium, making the ventricle appear to pump more efficiently than it actually is 1. In contrast, ejection fraction is not a reliable indicator of cardiac dysfunction in the elderly as age-related changes can affect measurements. In mitral stenosis, ejection fraction is usually normal or only slightly reduced since the problem is with filling rather than ejection. Some studies have shown that reduced LVEF has been the most consistently reported risk factor for overall mortality and SCD in the heart failure population 1. However, the relationship between left ventricular systolic dysfunction and death due to progressive heart failure and ventricular arrhythmias in patients who have had an MI is well established, and LVEF ≤ 40% serves as the threshold for identifying high-risk individuals 1. The development of concentric hypertrophy appears to be an appropriate and beneficial adaptation to compensate for high intracavitary pressures, but this adaptation often carries adverse consequences, such as reduced coronary blood flow per gram of muscle and also exhibit a limited coronary vasodilator reserve, even in the absence of epicardial CAD 1. A decrease in ejection fraction during exercise should not be used as the only indication for AVR in asymptomatic patients with normal LV systolic function at rest, because the exercise ejection fraction response is multifactorial, and the strength of evidence is limited 1. Ejection fractions have the same adverse outcome as symptomatic patients with LV dysfunction; however, subsequent data indicate a poor outcome for symptomatic patients with medical therapy, among even those with preserved LV systolic function 1. The most recent study from 2024, provides information on the association of Heart Failure and Left Ventricular Ejection Fraction With 90-day Mortality in Patients Undergoing Noncardiac Surgery, but does not directly answer the question, however, it provides insight into the importance of LVEF in patients with heart failure 1. Considering the provided options and the information from the studies, the most accurate statement is that ejection fraction is typically increased in mitral incompetence (regurgitation).

From the Research

Cardiac Ejection Fraction

• The cardiac ejection fraction is not always an accurate indicator of cardiac dysfunction, especially in certain conditions such as mitral stenosis or regurgitation 2.
• In mitral stenosis, the left ventricular ejection fraction can be impaired due to reduced preload and increased afterload, but this is not always the case 2.
• In mitral regurgitation, the left ventricular ejection fraction can be normal or even increased due to the volume overload and eccentric hypertrophy of the left ventricle 2.
• The ejection fraction is a dimensionless number whose interpretation can be ambiguous and misleading, and its use as a clinical marker of cardiac function has been questioned 3.
• The relationship between ejection fraction and risk in patients with heart failure is modified by factors such as hypertension, diabetes, and renal function, and a more comprehensive assessment of cardiac function is needed 4.

Specific Conditions

• In patients with mitral stenosis and moderately reduced left ventricular ejection fraction, the outcome after mitral valve replacement can be affected, with a higher incidence of heart failure and admissions, but overall mortality is not different from that of patients with normal ejection fraction 5.
• The use of ejection fraction as a diagnostic and prognostic tool has been widely recognized, but its limitations and potential biases need to be considered, especially in the context of newer markers of left ventricular function 6.

Ejection Fraction in Different Contexts

• The ejection fraction can be increased in certain conditions such as mitral regurgitation, but decreased in others such as mitral stenosis or ventricular septal defect, highlighting the need for a more nuanced understanding of its role in different cardiac conditions 2, 3, 4.
• The ejection fraction is not always a reliable indicator of cardiac function, and its use should be complemented by other measures of cardiac structure and function, as well as clinical parameters and biomarkers 4, 6.