Left Ventricular Fibrosis on T1 Mapping is Associated with Increased Risk of Incident Atrial Fibrillation: Results from the Multi-Ethnic Study of Atherosclerosis (MESA).

Left Atrial Remodeling, Hemodynamic Burden, and Time-Varying Risk of Newly Documented Atrial Fibrillation in Heart Failure With Preserved Ejection Fraction

Atrial fibrillation modifies the association between CT-derived epicardial adipose tissue volume and left atrial remodeling in valvular heart disease.

BACKGROUND Epicardial adipose tissue volume (EATv) is associated with atrial fibrillation (AF), but whether AF modifies the association between EATv and atrial remodeling in valvular heart disease remains unclear. OBJECTIVE To determine whether AF modifies the association between CT-derived EATv and left atrial remodeling. METHODS This retrospective valvular surgery cohort included 436 patients (218 AF, 218 sinus rhythm [SR]) after 1:1 propensity score matching. Multivariable linear and logistic regression assessed associations of EATv with left atrial volume index (LAVI) and left atrial enlargement (LAE). Restricted cubic spline, ROC curve and mitral regurgitation-stratified sensitivity analyses were performed. Exploratory histology and EAT secretome analyses were conducted in surgical samples. RESULTS Patients with AF had higher EATv and larger atria than those with SR. In the primary adjusted model, each 10-cm3 increase in EATv was associated with a 1.21-mL/m2 higher LAVI in SR and a 4.45-mL/m2 higher LAVI in AF (P for interaction = .002). EATv was associated with LAE (OR 1.29, 95% CI 1.17-1.43), with a significant AF-by-EATv interaction (OR 1.41, 95% CI 1.15-1.74). Adding EATv improved discrimination for LAE (AUC 0.767 to 0.804; P = .007). Exploratory tissue analyses suggested adipocyte hypertrophy, fibrosis, and reduced Wnt-antagonist secretion in AF-associated EAT. CONCLUSIONS Higher CT-derived EATv was associated with more advanced left atrial remodeling, with stronger associations in AF than in SR. EATv may serve as a CT-derived marker of remodeling vulnerability in valvular heart disease.

Left Atrial Strain Prediction of New-Onset Atrial Fibrillation in Apical Hypertrophic Cardiomyopathy with Cardiac MRI.

Purpose To evaluate the predictive value of cardiac MRI-derived left atrial strain (LAS) for new-onset atrial fibrillation (AF) in apical hypertrophic cardiomyopathy (AHCM). Materials and Methods This retrospective study included patients with AHCM with no prior history of AF who underwent 3.0-T cardiac MRI between May 2016 and December 2023. LAS parameters-reservoir strain (εs), conduit strain (εe), and booster pump strain (εa)-and minimum left atrial volume index (LAVImin) were measured. The clinical end point was new-onset AF as confirmed with electrocardiography, Holter monitoring, or implantable cardiac devices. Cox proportional hazards models and time-dependent receiver operating characteristic (ROC) analyses were performed to evaluate associations and discriminatory performance for new-onset AF. Results A total of 156 patients (mean age, 51.0 years ± 11.5 [SD]; 113 male) were included. During a median follow-up of 33 months, AF occurred in 21 patients. In multivariable Cox models adjusted for age, body mass index, and LAVImin, LAS parameters were independently associated with incident AF (εs: hazard ratio [HR], 0.79 [95% CI: 0.69, 0.90], P < .001; εa: HR, 0.65 [95% CI: 0.50, 0.83], P < .001; and εe: HR, 0.79 [95% CI: 0.65, 0.95], P = .01). In the nested Cox models, adding LAS to a baseline clinical-volumetric model improved model fit and discrimination, with the χ2 value improving from 36.22 to 54.90 and the concordance index value improving from 0.846 to 0.930 (P < .001 for both). The LAVImin provided complementary prognostic information, with its contribution varying across strain-specific models. Time-dependent ROC analyses demonstrated that LAS identified the development of AF well across prespecified time horizons. Conclusion Cardiac MRI-derived LAS was independently associated with new-onset AF in AHCM and provided incremental prognostic value beyond routine clinical and left atrial volumetric measures. Keywords: Apical Hypertrophic Cardiomyopathy, Atrial Fibrillation, Cardiac MRI, Left Atrial Strain, Heart, Cardiomyopathies, MR Imaging Supplemental material is available for this article. © RSNA, 2026.

Integrated Left Ventricular Mass and Left Atrial Function for Prediction of Cardiovascular Outcomes: The Multi-Ethnic Study of Atherosclerosis (MESA).

Background: Left ventricular (LV) mass and left atrial (LA) strain are physiologically coupled and individually predict adverse cardiovascular outcomes. Their imbalance may reflect early atrioventricular uncoupling and atrial myopathy before overt structural disease. Aims: We evaluated whether a cardiac magnetic resonance (CMR)-derived LV mass-to-LA strain ratio identifies early atrioventricular mechanical uncoupling and predicts cardiovascular events. Methods: Participants from the Multi-Ethnic Study of Atherosclerosis (MESA) underwent CMR at Exams 1 (2000-2002) and 5 (2010-2012). The LV mass-to-LA strain ratio was calculated as indexed end-diastolic LV mass divided by peak LA strain. Classification and regression tree analysis identified cut points for baseline ratio and longitudinal change, defining low (<1.04), reference (1.04-3.26), and high (>3.26) groups, and lesser-(≤130%) versus greater-change (>130%) groups. Multivariable Cox models assessed associations with heart failure (HF), atrial fibrillation (AF), myocardial infarction (MI), and all-cause mortality. Results: Among 4,232 participants (mean age 61.5±10.1 years; 52.8% female), the mean ratio was 1.95±0.72. Over a median 18-year follow-up, 6.0% developed HF, 5.2% MI, 18.7% AF, and 25.6% died. A high LV mass-to-LA strain ratio independently predicted HF (HR 2.85), AF (HR 2.00), MI (HR 1.96), and death (HR 1.70; all P≤.003). With repeat CMR, an increasing ratio also predicted cardiovascular events, including among individuals with normal LV mass and LA strain. Higher baseline ratios were associated with progression toward abnormal volumetric atrioventricular coupling over time. Conclusion: A higher LV mass-to-LA strain ratio and its increase independently predict cardiovascular events before overt chamber abnormalities, supporting impaired atrial adaptation as an early stage of atrial myopathy.

Determinants, risk score, and prognostic implications of left ventricular thrombus in ischemic cardiomyopathy assessed by cardiac magnetic resonance: a retrospective cohort study

Abstract Background Left ventricular thrombus (LVT) is a significant complication in ischemic cardiomyopathy (ICM). However, factors associated with LVT have mainly been reported in patients with recent myocardial infarction (MI), while data in chronic ICM remain limited. This study aimed to identify factors associated with CMR-detected LVT in patients with chronic ICM (left ventricular ejection fraction [LVEF] < 50% of ischemic etiology, >40 days post-MI), develop a CMR-based risk score, and evaluate the prognostic implications of LVT on major adverse cardiovascular events (MACE). Methods This study included 790 patients with ICM who underwent CMR at an academic hospital in Thailand between 2016 and 2023. Factors associated with LVT were identified using logistic regression analyses. A CMR-based risk score was developed and validated, with discriminative performance assessed by the area under the receiver operating characteristic curve (AUC-ROC). MACE, defined as a composite of cardiovascular death, ischemic stroke, transient ischemic attack, systemic embolism, nonfatal MI, or heart failure hospitalization, was also evaluated. Factors associated with MACE were assessed using Cox regression analysis. Results The mean age was 66.9 ± 11.3 years, and 75.3% were male. LVT was detected in 116 patients. Independent factors associated with LVT included apical aneurysm, apical late gadolinium enhancement (LGE), and the number of LGE segments. The CMR-LVT Score, incorporating these variables, demonstrated an AUC of 0.73 (95%CI, 0.68–0.77;p < 0.001) in the derivation cohort and 0.79 (95%CI, 0.69–0.90;p < 0.001) in the validation cohort. During a median follow-up of 3.2 years (IQR, 1.6–5.5), 150 MACE occurred. Baseline LVT was independently associated with MACE (adjusted HR 2.38, 95%CI 1.31–4.30;p = 0.004). Conclusions In patients with ICM undergoing CMR, apical aneurysm, apical LGE, and LGE extent were independently associated with LVT. The CMR-LVT Score demonstrated acceptable discriminative performance for identifying higher-risk patients who may benefit from more intensive follow-up. LVT was also independently associated with MACE.

Association of Left Atrial Structure and Function with Incident Atrial Fibrillation in Black and White Adults: the ARIC Study

Background: Black individuals have a lower incidence of atrial fibrillation (AF) than White individuals despite a higher burden of many traditional cardiovascular risk factors. Differences in left atrial (LA) structure and function by race could partly explain the observed pattern of AF risk. Methods: This analysis included 4,576 (978 Black and 3,598 White) participants from the Atherosclerosis Risk in Communities (ARIC) study, followed between 2011 and 2021. The association of selected echocardiographic measures of LA structure and function with AF incidence was evaluated with race-specific Cox proportional hazards models with adjustment for sociodemographic and clinical covariates. Additional analyses assessed whether LA measures attenuated the association between race and incident AF. Results: The analysis included 778 AF cases (113 in Black and 665 in White participants, mean age 75 years). Larger LA size and worse LA function were associated with higher AF risk in both Black and White individuals, with most associations of similar magnitude in both groups, except for a slightly stronger association of LA reservoir strain in Black than White participants (Black: hazard ratio (HR) 0.89, 95% CI 0.86-0.92 per 1% increase; White: HR 0.94, 95% CI 0.92-0.95, p for interaction = 0.01). In the overall sample, White participants showed higher AF risk compared to Black participants (HR 1.59, 95% CI 1.24-2.03). Adjustment for most individual LA measures did not attenuate the association between race and AF risk. Conclusion: Larger LA size and worse LA function were associated with incident AF in both Black and White ARIC participants. However, these measures did not explain the lower AF incidence observed among Black participants. LA remodeling appears to be an important predictor of AF risk, but it is not the primary explanation for the Black-White AF paradox.