Atrial fibrillation (AF) is the most common sustained arrhythmia. LA and LV parameters have both a prognostic value to predict AF occurrence when taken separately. Based on the close physiological interaction between LA and LV, the simultaneous assessment of the left atrioventricular coupling could be even more accurate to predict AF. However, no data has been described on the existence of such an atrioventricular index.

This study aimed to investigate the prognostic value of a novel left atrioventricular coupling index (LACI) that integrates LA and LV parameters and to assess its predictive value for AF occurrence throughout adult life in a large population without a history of CV diseases.

A total of 4124 participants in the multi-ethnic study of atherosclerosis (MESA) underwent a cardiac MRI study. The LACI by cardiac MRI was defined by the ratio of the indexed LA end-diastolic volume divided by the indexed LV end-diastolic volume. Cox proportional hazard models were constructed to predict the occurrence of AF. In univariable and multivariable Cox analysis, the association between LACI or all other LA and LV variables and time-to-event was analysed, adjusting for traditional AF factors.

A total of 237 (5.7%) patients experienced AF during a median (IQR) follow-up period of 10.8 (7.8–11.4) years. In univariate analysis, LACI was associated with incident AF (HR: 2.13, 95% CI [1.97–2.31] P<0.0001). In Cox multivariable analysis, LACI had a significant independent predictive value for AF (adjusted HR: 1.91, 95% CI [1.73–2.08] P<0.0001). Regarding the inter-models comparison to predict the occurrence of AF, C-statistic for LACI (0.76) was greater than LAVI_min (0.74), LA strain (0.71), LAVI_max (0.70) or LVEF (0.53). LACI showed better predictive performance than the multivariate model, including traditional AF risk factors (C-statistic: 0.85 versus 0.80) (Fig. 1).

The LACI was an independent predictor of incident AF.