Reference values of left atrial size and function according to age: should we redefine the normal upper limits?

Area of Science:

• Cardiology
• Echocardiography
• Geriatric Medicine

Background:

• Left atrial (LA) size and function are crucial cardiovascular parameters.
• Existing reference values for LA size lack consensus, and the influence of aging on LA size and myocardial function remains unclear.
• Accurate reference values are essential for diagnosing and managing cardiovascular conditions.

Purpose of the Study:

• To establish reference values for LA size and function in healthy individuals across different age groups.
• To investigate the impact of age on LA size and myocardial function.
• To determine if current reference values for LA volume index (LAVi) are appropriate for all age groups.

Main Methods:

• Systematic literature search of the MEDLINE database.
• Inclusion of studies evaluating healthy subjects aged 18-80 years.
• Comparison of LA parameters among four age groups: <30, 30-45, >45-60, and >60 years, analyzing data from 62,821 subjects.

Main Results:

• Left atrial volume index (LAVi) did not differ significantly across age groups (p=0.21), with a normal upper limit of 24 mL/m².
• LA reservoir function, measured by strain, remained consistent among age groups (p=0.74).
• Advancing age was associated with a decreased E/A ratio and an increased E/e' ratio (p<0.0001 and p=0.001, respectively), indicating age-related changes in diastolic function.

Conclusions:

• The normal upper limit of LAVi in healthy individuals is 24 mL/m² and is not influenced by advancing age.
• LA function, assessed by strain, is preserved with age in healthy subjects.
• Current reference values for LAVi should be applied with caution in clinical practice, particularly when assessing healthy aging populations.