What are the left atrial (LA) volume, LA area in the apical four-chamber (A4C) view, and LA area in the apical two-chamber (A2C) view, as well as the calculated stroke volume (SV), ejection fraction (EF), and cardiac index (CI) used to assess cardiac function?

From the Guidelines

The provided left atrial (LA) volumes from apical four-chamber (A4C) and two-chamber (A2C) views are 26.5 ml and 17.0 ml respectively, which are within normal range, as indicated by the 2016 ASE/EACVI recommendations 1. The stroke volume of 39.4 ml indicates the amount of blood pumped per heartbeat, while the ejection fraction of 65.3% shows good systolic function (normal is typically above 55%) 1. The cardiac index of 25.6 ml/m² represents cardiac output adjusted for body size. These parameters are used by medical professionals to assess cardiac function, particularly left ventricular performance and left atrial size. The normal ejection fraction suggests good heart contractility, though the stroke volume is slightly lower than typical values. These measurements help clinicians evaluate heart function, diagnose conditions like heart failure, and monitor response to treatments. Regular follow-up echocardiograms may be recommended to track any changes in these parameters over time, especially if there are symptoms of heart disease, as suggested by the 2018 European Journal of Heart Failure study 1. Key parameters to evaluate include left atrial volume index (LAVI), left ventricular mass index (LVMI), myocardial tissue velocity (e’), and the ratio of early mitral inflow E to e’ (E/e’) 1. The 2016 Circulation study emphasizes the importance of measuring the LA volume by the biplane disk method from the apical 4- and 2-chamber view at end systole 1. In clinical practice, these measurements are crucial for assessing cardiac function and guiding treatment decisions, with the goal of reducing morbidity, mortality, and improving quality of life. Some of the key points to consider when evaluating these parameters include:

• Left atrial volume index (LAVI) is a marker of long-term or chronic elevation of left atrial pressure (LAP) 1
• Left ventricular mass index (LVMI) is associated with increased left ventricular stiffness and diastolic dysfunction 1
• Myocardial tissue velocity (e’) is a measure of left ventricular diastolic function 1
• The ratio of early mitral inflow E to e’ (E/e’) is a measure of left ventricular filling pressure 1

From the Research

LA Volume and Calculations

• The given LA volume values are:
  • LA A4Cs: 26.5 ml
  • LA A2Cs: 17.0 ml
• The calculations provided are:
  • SV (A4C): 39.4 ml (Stroke Volume)
  • EF (A4C): 65.3% (Ejection Fraction)
  • CI (A4C): 25.6 ml/m' (Cardiac Index)

Assessment of Cardiac Structure and Function

• According to 2, left ventricular ejection fraction (LVEF) has limitations as a measure of cardiac function, and a more comprehensive assessment is needed to evaluate left ventricular function in patients with heart failure.
• The study 2 suggests that an integrative approach incorporating measures of left and right ventricular function, left ventricular geometry, left atrial size, and valvular function, as well as non-imaging factors, is necessary for a comprehensive evaluation of cardiac structure and function.

Heart Failure with Preserved Ejection Fraction

• Heart failure with preserved ejection fraction (HFpEF) is a common condition, accounting for almost half of the 5 million cases of heart failure in the United States, as stated in 3.
• The diagnosis of HFpEF should be suspected in patients with typical symptoms and signs of chronic heart failure, and echocardiographic findings of normal ejection fraction with impaired diastolic function confirm the diagnosis 3.
• The study 4 found that coronary artery disease (CAD) is common in patients with HFpEF and is associated with increased mortality and greater deterioration in ventricular function.

Diastolic Function and Heart Failure

• According to 5, the diagnosis of diastolic heart failure can be made without the measurement of parameters that reflect left ventricular diastolic function, as the vast majority of patients with heart failure and a normal ejection fraction exhibit abnormal left ventricular diastolic function.
• The study 5 found that one or more indexes of diastolic function were abnormal in every patient with heart failure and a normal ejection fraction.

Coronary Artery Disease and Mortality

• The presence and extent of CAD are strongly associated with all-cause mortality in patients with heart failure and reduced ejection fraction (HFrEF), as stated in 6.
• The study 6 found that CAD doubles excess mortality in patients with HFrEF compared to a matched general population.