From the Guidelines
The left atrium is normal in size with a trace indexed volume of 8.3 ml/m², which is below the normal range of 16-34 ml/m², as indicated by recent guidelines 1. This measurement suggests that the left atrium is functioning within normal parameters, but on the lower end of normal or slightly below normal range. A normal-sized left atrium indicates absence of left atrial enlargement, which is often associated with conditions like hypertension, mitral valve disease, or heart failure.
- Key points to consider:
- The normal range for left atrial volume index (LAVI) is >34 mL/m2 for males, as per the 2016 ESC heart failure guidelines and the 2016 ASE/EACVI recommendations 1.
- The trace indexed volume provides a standardized measurement that accounts for body size differences between individuals, making it a more accurate assessment than absolute volume alone.
- This finding is generally reassuring, though if the value is significantly below normal range, it might warrant clinical correlation to ensure there are no issues with left atrial filling or other cardiac parameters.
- It is essential to consider other echocardiographic variables, such as left ventricular mass index (LVMI), E/e’, and e’ (mean), to get a comprehensive assessment of cardiac function 1.
From the Research
Left Atrium Size and Volume
- The left atrium size and volume can be measured using various methods, including echocardiography 2, 3, 4, 5, 6.
- A normal left atrium size is typically considered to be less than 34 mm in anteroposterior diameter, and a normal left atrium volume is typically considered to be less than 28 ml/m² 3, 5.
- In the given scenario, the left atrium volume is 8.3 ml/m², which is within the normal range.
Predictors of Catheter Ablation Success
- The success of catheter ablation for atrial fibrillation can be predicted using various parameters, including left atrium size and function 2, 4.
- A study found that global left atrial reservoir strain (LASr) was an independent predictor of catheter ablation success, with an odds ratio of 1.35 for each 1% increase in LASr 2.
- Another study found that left atrium size, measured as left atrial volume indexed to body surface area (LAVi), was a predictor of stroke risk in patients with non-valvular atrial fibrillation 5, 6.
Left Atrium Size and Stroke Risk
- An enlarged left atrium is associated with an increased risk of stroke, particularly in patients with atrial fibrillation 3, 5, 6.
- A study found that LAVi was the best left atrial measurement for predicting stroke risk, with an odds ratio of 1.73 for each unit increase in LAVi 5.
- Another study found that indexed left atrial area in four-chamber view and indexed area-length volumes were independent predictors of surrogate markers of stroke in patients with non-valvular atrial fibrillation 6.