Change in Left Atrioventricular Coupling Index to Predict Incident Atrial Fibrillation: The Multi-Ethnic Study of Atherosclerosis (MESA)

Abstract

Background Left atrial (LA) and left ventricular (LV) structural and functional parameters have independent prognostic values as predictors of atrial fibrillation (AF). Purpose To investigate the prognostic value of a left atrioventricular coupling index (LACI) and average annualized change in LACI (hereafter, ΔLACI) measured by cardiac MRI to predict incident AF in a population-based sample from the Multi-Ethnic Study of Atherosclerosis (MESA). Materials and Methods In a secondary analysis of the prospective MESA, 1911 study participants without clinically recognized AF and cardiovascular disease at baseline had LACI assessed with cardiac MRI at baseline (examination 1, 2000-2002) and 10 years later (examination 5, 2010-2012). LACI was defined as the ratio of LA to LV end-diastolic volumes. Univariable and multivariable Cox proportional hazard models were used to evaluate the associations of LACI and average ΔLACI with incident AF. Results Among the 1911 participants (mean age, 59 years ± 9 [standard deviation]; 907 men), 87 incident AF events occurred over 3.9 years ± 0.9 after the second imaging (examination 5). After adjustment for traditional risk factors, greater LACI and ΔLACI were independently associated with AF (hazard ratio, 1.69 [95% CI: 1.46, 1.96] and 1.71 [95% CI: 1.50, 1.94], respectively; both P < .001). Adjusted models for LACI and ΔLACI showed improvement in model discrimination compared with currently used AF risk score (Cohort for Heart and Aging Research in Genomic Epidemiology-Atrial Fibrillation, or CHARGE-AF, score) model (area under receiver operating characteristic curve [AUC], 0.78 vs 0.74; and AUC, 0.80 vs 0.74, respectively; both P < .001); and to the final model including individual LA or LV parameters for predicting AF incidence (AUC, 0.78 vs 0.76; and AUC, 0.80 vs 0.78, respectively; both P < .001). Conclusion Atrioventricular coupling (left atrioventricular coupling index [LACI]) and coupling change (annual change in LACI) were strong predictors for atrial fibrillation (AF) in a multiethnic population. Both had incremental prognostic value for predicting AF over traditional risk factors, and superior discrimination compared with the Cohort for Heart and Aging Research in Genomic Epidemiology-Atrial Fibrillation, or CHARGE-AF, score and to individual left atrial or left ventricular parameters. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Leiner in this issue.

Graphical abstract

Figure 1:

Flowchart of the study. Mean time between baseline and second cardiac MRI examinations, 9.6 years ± 0.4 (1). Mean time of AF follow-up: 3.9 years ± 0.9 after the second cardiac MRI examination (2). AF = atrial fibrillation, MESA = Multi-Ethnic Study of Atherosclerosis.

Figure 2:

Method to assess the left atrioventricular coupling index (LACI) at cardiac MRI. LACI was defined by the ratio between the left atrial (LA) end-diastolic volume and the left ventricular (LV) end-diastolic volume. A stack of short-axis noncontrast cine MRI scans were acquired to encompass both ventricles, and LV end-diastolic volume was measured by using cardiac image modeler software (green volume, left panel). LA end-diastolic volume was measured by using multimodality tissue-tracking software to track LA wall motion during the end-diastole in the four-chamber and two-chamber views (pink borders, right panel).

Figure 3:

Kaplan-Meier survival curves for incident atrial fibrillation (AF) stratified by (A) left atrioventricular coupling index (LACI) terciles and by (B) a LACI cutoff of 30%. (A) The cumulative hazard was greater in the third LACI value measured after 10 years (LACI₁₀) tercile compared with the first tercile for incident AF (hazard ratio [HR], 2.48; 95% CI: 1.53, 3.87; P < .001). (B) The cumulative hazard was greater for participants with LACI₁₀ greater than 30% compared with participants with LACI₁₀ of 30% or less for incident AF (HR, 2.62; 95% CI: 1.72, 4.00; P < .001).

Figure 4:

Kaplan-Meier survival curves for incident atrial fibrillation (AF) stratified by terciles of annual change (Δ) in left atrioventricular coupling index (LACI) (A) and by annual change in LACI with a cutoff of 1.5% per year (B). (A) The cumulative hazard was greater in the third tercile compared with the first tercile for incident AF (hazard ratio [HR], 2.52; 95% CI: 1.57, 3.96; P < .001). (B) The cumulative hazard was greater for participants with LACI greater than 1.5% per year compared with participants with annual change in LACI of 1.5% or less per year for incident AF (HR, 2.77; 95% CI: 1.82, 4.21; P < .001).

Figure 5:

Kaplan-Meier survival curves for incident atrial fibrillation (AF) stratified simultaneously by left atrioventricular coupling index (LACI) value measured after 10 years (LACI₁₀) with a cutoff of 30% and an annual change (Δ) in LACI with a cutoff of 1.5% per year. In participants with a LACI₁₀ greater than 30%, the cumulative hazard was greater for participants with annual change in LACI greater than 1.5% per year than for those with annual change LACI of 1.5% or less per year (hazard ratio [HR], 2.20; 95% CI: 1.08, 4.15; P < .001). However, among participants with LACI₁₀ of 30% or less, we found no evidence of differences between those with annual change in LACI greater than or less than 1.5% per year (HR, 1.19; 95% CI: 0.87, 1.89; P = .46).