Both left atrial (LA) and left ventricular (LV) functional parameters influence the prognosis of patients with cardiovascular diseases (CVD).

This study aimed to investigate the prognostic value of a novel left atrioventricular coupling index (LACI), as well as annual change in LACI (ΔLACI) for predicting hard CVD in a population without history of CVD at baseline.

In the Multi-Ethnic Study of Atherosclerosis (MESA), 2221 study participants, free of CVD at baseline, had LACI assessed with CMR imaging at baseline (Exam 1, 2000–2002), and ten years later (Exam 5, 2010–2012). LACI was defined by the ratio of the LA end-diastolic volume divided by the LV end-diastolic volume. Cox proportional hazard models were used to evaluate the associations of LACI and average annualized change in LACI (ΔLACI) with hard CVD defined by myocardial infarction, resuscitated cardiac arrest, fatal and nonfatal stroke, or CHD death.

Among the 2221 participants (62.8±10.1years, 47.9% men), 223 cardiovascular events were observed (mean follow-up 13.0±3.2 years). After adjustment for traditional risk factors, greater LACI and ΔLACI were independently associated with hard CVD (HR: 1.23; 95% CI [1.13–1.34] and HR: 1.71, 95% CI [1.50–1.94]; both P<0.0001). Adjusted models for LACI and ΔLACI showed significant improvement in model discrimination compared to traditional risk score model (C-statistic: 0.79 vs. 0.77, and C-statistic: 0.80 vs. 0.78, respectively) (Fig. 1).

LACI is a strong predictor for the incidence of hard CVD. LACI has incremental prognostic value to predict hard CVD over traditional risk factors, and better discrimination and reclassification power compared to individual LA or LV parameters.