Left atrial structure and function and clinical outcomes in the general population

Area of Science:

• Cardiology
• Cardiovascular Imaging
• Biomarkers

Background:

• Left atrial (LA) structural and functional abnormalities can represent subclinical phenotypes.
• These abnormalities may identify individuals at increased risk of adverse cardiovascular outcomes.

Purpose of the Study:

• To assess the associations of LA maximum volume indexed to body surface area (LAmax/BSA) and LA emptying fraction (LAEF) with cardiovascular risk factors and left ventricular (LV) structure and function.
• To evaluate the incremental prognostic value of LAmax/BSA and LAEF beyond traditional risk factors and LV parameters for mortality.

Main Methods:

• Cardiac magnetic resonance imaging (CMR) was used to measure LAmax/BSA and LAEF in 1802 participants from the Dallas Heart Study.
• Linear regression and Cox proportional-hazards models were employed to analyze associations with risk factors, LV parameters, and mortality.
• The incremental prognostic value was assessed by comparing c-statistics before and after adding LA parameters to established risk models.

Main Results:

• Both increasing LAmax/BSA and decreasing LAEF were associated with hypertension and elevated natriuretic peptide levels.
• LAmax/BSA was strongly associated with LV end-diastolic volume/BSA, while LAEF correlated with LV ejection fraction and concentricity.
• Decreasing LAEF, but not increasing LAmax/BSA, was independently associated with increased mortality (HR per 1 SD: 1.56; P < 0.001).
• LAEF significantly improved the c-statistic for mortality prediction (0.78 vs. 0.77; P < 0.05), whereas LAmax/BSA did not (0.76; P = 0.20).

Conclusions:

• LAmax/BSA and LAEF are significant subclinical phenotypes in the general population.
• LAEF demonstrates superior and incremental prognostic value for mortality compared to LAmax/BSA.
• LAEF is a valuable biomarker for identifying individuals at higher risk of adverse cardiovascular events.