Aims Longitudinal change in left atrial (LA) structure and function could be helpful in predicting risk for incident atrial fibrillation (AF). We used cardiac magnetic resonance (CMR) imaging to explore the relationship between change in LA structure and function and incident AF in a multi-ethnic population free of clinical cardiovascular disease at baseline. Methods and results In the Multi-Ethnic Study of Atherosclerosis (MESA), 2338 participants, free at baseline of clinically recognized AF and cardiovascular disease, had LA volume and function assessed with CMR imaging, at baseline (2000–02), and at Exam 4 (2005–07) or 5 (2010–12). Free of AF, 124 participants developed AF over 3.8 ± 0.9 years (2015) following the second imaging. In adjusted Cox regression models, an average annualized change in all LA parameters were significantly associated with an increased risk of AF. An annual decrease of 1-SD unit in total LA emptying fractions (LAEF) was most strongly associated with risk of AF after adjusting for clinical risk factors for AF, baseline LA parameters, and left ventricular mass-to-volume ratio (hazard ratio per SD = 1.91, 95% confidence interval = 1.53–2.38, P < 0.001). The addition of change in total LAEF to an AF risk score improved model discrimination and reclassification (net reclassification improvement = 0.107, P = 0.017; integrative discrimination index = 0.049, P < 0.001). Conclusion In this multi-ethnic study population free of clinical cardiovascular disease at baseline, a greater increase in LA volumes and decrease in LA function were associated with incident AF. The addition of change in total LAEF to risk prediction models for AF improved model discrimination and reclassification of AF risk.

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Introduction: Hemolysis is a frequent complication in cardiogenic shock patients supported with Impella and can lead to acute kidney injury (AKI). We assessed the association between three hemolysis biomarkers, lactate dehydrogenase (LDH), plasma-free hemoglobin (pfHb), and haptoglobin, and AKI to determine the optimal biomarker in predicting AKI. Methods: Cardiogenic shock patients on Impella support (CP or 5.0) for more than 24 hours from 6/1/2016 to 9/1/2020 at the University of Washington Medical Center were retrospectively enrolled. By institutional protocol, the three biomarkers were measured daily while patients were on Impella support. The association between each biomarker and the development of stage 2 or worse AKI (creatinine increase of ≥ 100% or requiring hemodialysis) within 24 hours of biomarker collection was assessed using logistic regression. Plots of AKI probability over the range of values of each biomarker were constructed using natural splines. Results: Out of 251 included patients (mean age 56.2 ± 15.8 years, 78% male, 69% white), 128 (51%) developed stage 2 or worse AKI. LDH and pfHb values had statistically significant associations with the development of stage 2 or worse AKI within 24 hours of each measurement (OR 1.016 [95% CI 1.009-1.022] per 100 IU/L of LDH, OR 1.092 [95% CI 1.067-1.117] per 10 mg/dL of pfHb, p-value < 0.001 for both) while haptoglobin values did not (p-value 0.6). The association with AKI was stronger for pfHb compared to LDH (McFadden’s R 2 0.12 for pfHb vs 0.03 for LDH). The association of each biomarker and AKI is illustrated in Figure 1. Conclusions: In cardiogenic shock patients supported with Impella, higher LDH and pfHb values were associated with AKI while haptoglobin values were not, and pfHb had a stronger association with AKI than LDH. Our results support the use of pfHb to detect hemolysis and risk of impending AKI in patients supported with Impella. Figure 1. Probability of stage 2 or worse AKI based on biomarker values.

Introduction: Left atrial (LA) structure and function are associated with future cardiovascular (CV) events and risk factors. Studying the longitudinal change of LA structure and function with age may provide important insights into the natural history of LA remodeling. Hypothesis: The aim of this study is to evaluate associations between age and gender with longitudinal changes in LA remodeling in a large multi-ethnic cohort free of clinical CV disease at baseline. Methods: Cardiac magnetic resonance (CMR) was used to identify longitudinal changes in LA structure and function in 2882 MESA participants who underwent baseline (year 2000-2002) and 10-year follow-up CMR imaging. Multimodality tissue tracking (MTT, Toshiba) software was used to calculate LA structure (LA maximum, minimum and pre-atrial contraction volumes indexed to body surface area - LA Vmax, Vmin and VpreA) and function (LA total, passive and active emptying fraction, LATEF, LAPEF, and LAAEF). Data were analyzed with multivariable mixed-effects regression models in which the outcome was CMR LA measurements, and the covariates included follow-up time and CV risk factors (hypertension, diabetes, smoking, race/ethnicity, body mass index, and lipid levels). Results: Participants were aged 45-84 years at baseline, and 53% were women. At baseline, men had lower LATEF than women (58.4 vs 63.4%, p<0.05), while they had similar LA Vmax (30.3 vs 29.9 ml/m2, p=NS) and larger Vmin (13.1 vs 11.5 ml/m2, p=NS). Median time between baseline and follow-up CMR imaging was 9.4 years. Over this period, LA Vmax and Vmin increased in both men (by 4.8 and 5.2 ml/m2 respectively, p<0.05) and women (by 4.9 and 4.6 ml/m2 respectively, p<0.05); while LATEF decreased in both (-7.3 % in women, and -6.1% in men, p<0.05). Conclusions: In a population free of CV disease, at baseline women had higher LA function than men, as well as lower LA volumes. Aging was associated with increased LA volume and decreased LA function in both men and women.