From the Guidelines
A left atrial indexed volume of 8.3 ml/m² is abnormally low and potentially concerning, indicating left atrial underfilling which may be associated with hypovolemia, mitral stenosis, or constrictive/restrictive cardiac conditions, as suggested by the 2015 ACC/AHA key data elements and definitions for cardiovascular endpoint events in clinical trials 1. This low measurement could also result from measurement error during echocardiography. Normal left atrial volume index typically ranges between 16-34 ml/m², with values below 16 ml/m² considered reduced, according to the 2012 ESC guidelines for the diagnosis and treatment of acute and chronic heart failure 1. Some key points to consider in this scenario include:
- Clinical correlation with symptoms and other cardiac parameters is necessary to determine the clinical significance of this finding
- Patients with abnormally low left atrial volumes may experience symptoms like fatigue, dizziness, or exercise intolerance depending on the underlying cause
- Further cardiac evaluation is recommended, including comprehensive echocardiography to assess other cardiac chambers and valvular function, along with clinical assessment of volume status and cardiac symptoms to guide appropriate management, as outlined in the 2015 ACC/AHA key data elements and definitions for cardiovascular endpoint events in clinical trials 1. The most recent and highest quality study, the 2015 ACC/AHA key data elements and definitions for cardiovascular endpoint events in clinical trials 1, provides the most relevant guidance for this scenario, superseding the 2012 ESC guidelines 1.
From the Research
Left Atrium Size and Volume
- The left atrium size and volume can be an indicator of various heart conditions, including heart failure, atrial fibrillation, and hypertension 2, 3.
- A study found that the indexed left atrium volume was greater in hypertensive patients compared to healthy volunteers, with a mean volume of 34 ± 7.8 mL/m² versus 24 ± 4.9 mL/m² 3.
- Another study found that left atrium enlargement is associated with an increased prevalence of surrogate markers of stroke in patients with non-valvular atrial fibrillation, with indexed left atrium area and volume being independent predictors of these markers 4.
Normal Left Atrium Volume
- The normal left atrium volume is not strictly defined, but a volume of 8.3 mL/m² is considered relatively small.
- However, without more information about the individual's age, sex, and other health factors, it is difficult to determine whether this volume is abnormal or not.
- Studies have shown that left atrium volume can vary widely among healthy individuals, and that factors such as age, sex, and body size can influence left atrium size 2, 3.
Indexed Left Atrium Volume
- Indexed left atrium volume is a measure of left atrium volume that is adjusted for body size.
- A study found that an indexed left atrium volume of 34 ± 7.8 mL/m² was associated with hypertension and left atrium dysfunction 3.
- Another study found that indexed left atrium area and volume were independent predictors of surrogate markers of stroke in patients with non-valvular atrial fibrillation 4.
- In the context of the provided volume of 8.3 mL/m², it is unclear whether this is abnormal or not without more information about the individual's health status and other factors.