Assessing individuals' risk of developing incident atrial fibrillation (AF) is important for making preventive and screening strategies. The performance of the mC₂HEST score for predicting incident AF has scarcely been evaluated, especially in a multi-ethnic population. Participants from the MESA (Multi-Ethnic Study of Atherosclerosis were enrolled in the present study, which involved population of different ethnicities (Caucasian, African-American, Chinese-American, and Hispanic) aged between 45 and 84 from 6 communities in the United States. The discriminative and calibration performance of the mC₂HEST score was compared with other risk models. A total of 4,524 subjects (mean age 60.2 ± 9.5 years; 53.0% female) were included; 565 (mean age 67.0 ± 7.9 years; 46.5% female) developed AF during 13.6 ± 2.5 years of follow-up, with an incidence of 0.93%/year. The mC₂HEST score had good prediction at 10 years (C-index, 0.72; 95% CI: 0.701 to 0.753), and 15 years (0.773, 95% CI: 0.749 to 0.798). The risk of incident AF increased with higher mC₂HEST score points and risk groups (log-rank P < 0.001). The mC₂HEST score showed positive net reclassification indexes (0.057, 0.090, 0.128, and 0.143) and integrated discriminative improvement (3.2%, 3.9%, 5.7%, and 4.9%) compared with C₂HEST, HAVOC, HATCH, and CHA₂DS₂-VASc scores, respectively. Optimal calibration was seen in the mC₂HEST score (P = 0.41). The mC₂HEST score is a practical model for predicting individuals' risk of incident AF that may be used for guiding AF surveillance, resource allocation, and screening strategies.

Background: The associations between left atrial (LA) size, echocardiographic diastolic parameter (E/A ratio), and incident atrial fibrillation (AF) in older inpatients remain underexplored. Aims: This study aimed to evaluate the relationship between LA size, E/A ratio, and AF risk in older hospitalized patients. Methods: Between January 2015 and May 2023, a total of 2,615 older inpatients (aged ≥ 65 years) were enrolled in this retrospective longitudinal study. Left atrial diameter (LAD) and E/A ratio were measured using transthoracic echocardiography. Results: Over a median follow-up of 844 days (IQR: 331–1355 days), 209 patients (8.0%) experienced at least one incident of AF. After adjusting for covariates, large LA and high E/A ratio were significantly associated with incident AF, with an 11% increase in risk for each 1 mm increase in LAD over 35 mm (adjusted HR: 1.11, 95% CI: 1.10–1.13) and a 30% increased risk per standard deviation increase in E/A ratio when E/A ratio exceeded 0.65 (adjusted HR: 1.30, 95% CI: 1.23–1.37), P < 0.001. The influence of LA size and E/A ratio on incident AF was more pronounced in the younger subgroup of older adults. Incorporating LAD and E/A ratios into the CHA2DS2-VASc score improved its predictive accuracy (AUC _increase = 0.168, P < 0.001). Discussion: This study shows that LA size and E/A ratio are key predictors of AF in hospitalized older patients, with age influencing their predictive value. Incorporating these factors into the CHA2DS2-VASc score enhances risk stratification and highlights the need for early AF screening in this group. Conclusions: In hospitalized older patients, large LA and high E/A ratio are associated with incident AF, and these associations are more pronounced in younger individuals. LAD and E/A ratios provide incremental predictive value for AF beyond the CHA2DS2-VASc score. Graphical LA, left atrium; ASE: American Society of Echocardiography; E, mitral inflow velocity in the early diastolic phase; A, mitral inflow velocity in the late diastolic phase; AF: Atrial Fibrillation.