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BACKGROUND: Postoperative atrial fibrillation (PoAF) is a common complication after cardiac surgery. A pre-existing atrial substrate appears to be important in postoperative development of dysrhythmia, but its preoperative estimation is challenging. We tested the hypothesis that combining clinical predictors, noninvasive surrogate markers for atrial fibrosis defining abnormal left atrial (LA) mechanics, and biomarkers of collagen turnover is superior to clinical predictors alone in identifying patients at-risk for PoAF. METHODS: In patients without prior AF undergoing coronary artery bypass grafting, concentrations of biomarkers reflecting collagen synthesis and degradation, extracellular matrix, and regulatory microRNA29s were determined in serum from preoperative blood samples and correlated to atrial fibrosis extent, alteration in atrial deformation properties determined by 3D speckle-tracking echocardiography, and AF development. RESULTS: Of 90 patients without prior AF, 34 who developed PoAF were older than non-PoAF patients (72.04±10.7 y; P=0.043) with no significant difference in baseline comorbidities, LA size, or ventricular function. Global (P=0.007) and regional longitudinal LA strain and ejection fraction (P=0.01) were reduced in PoAF vs. non-PoAF patients. Preoperative amino-terminal-procollagen-III-peptide (PIIINP) (103.1±39.7 vs. 35.1±19.3; P=0.041) and carboxy-terminal-procollagen-I-peptide levels were elevated in PoAF vs. non-PoAF patients with a reduction in miR-29 levels and correlated with atrial fibrosis extent. Combining age as the only significant clinical predictor with PIIINP and miR-29a provided a model that identified PoAF patients with higher predictive accuracy. CONCLUSIONS: In patients without previous history of AF, using age and biomarkers of collagen synthesis and regulation, a noninvasive tool was developed to identify those at risk for new-onset PoAF.

article Background: Silent atrial fibrillation (AF) has been suggested to be frequent after acute myocardial infarction (MI). Continuous ECG monitoring (CEM) has been shown to improve AF screening in patients at risk of stroke. Objectives: We aimed to assess the incidence and prognosis of silent AF in patients with acute MI. Methods:All the consecutive patients with acute MI were prospectively analyzed by CEM ≥ 48 h after admission. Silent AF was defined as asymptomatic episodes lasting at least 30 s. The population was divided into three groups: no-AF, silent AF and symptomatic AF. Results:Among the 849 patients, 135(16%) developedsilentAF and45(5%)symptomatic AF.Comparedwith the no-AF group, patients with silent AF were markedly older (80 vs. 62 y, p b 0.001), more frequently women (43% vs. 30%, p = 0.006) and less likely to be smokers (20% vs. 36%, p b 0.001). They had impaired left ventricular ejection fraction (LVEF) and left atrial (LA) enlargement. By multivariate analysis, age, history of AF, indexed LA area and LVEF were identified as independent predictors of silent AF. In-hospital heart failure and death rates were markedly higher in silent AF group when compared with no-AF patients (41.8% vs 21.0% and 10.4% vs. 1.3%, respectively). Conclusion: Our large prospective study showed for the fi rst time that silent AF is more frequent than symptomatic AF after MI. Our work suggests that indexed LA area could help to predict the risk of developing silent AF. Moreover, the onset of silent AF is associated with worse hospital prognosis.

Pre-operative GDF-15 plasma levels significantly improve the prognostic value of the EuroSCORE for mortality after cardiac surgery. However, despite the strong correlation between GDF-15 and renal function, no data are available regarding the potential interest of pre-operative GDF-15 levels to improve the prediction of acute kidney injury (AKI) after cardiac artery bypass graft (CABG) surgery.All patients operated on by 2 surgeons for CABG surgery at our university hospital from September 2011 to March 2013 were screened for participation in this prospective, observational study.age18years or80years, previous atrial fibrillation/flutter, previous severe renal failure, previous cardiac surgery, emergency surgery. AKI was defined according to KDIGO criteria. GDF-15 levels in plasma were measured before induction and 12h after surgery.134 patients were included in this study. 42 (31%) developed post-operative AKI. AKI patients had a significantly higher pre-operative log-GDF-15 level (OR=3.64; 95% CI=1.41-9.40, p=0.008), a lower pre-operative eGFR (OR=0.98; 95% CI=0.96-0.99; p=0.026), and most often underwent on-pump surgery (OR=2.60; 95% CI=1.14-5.96, p=0.024). On ROC curves, GDF-15 before induction was found to be the best pre-operative biomarker to predict AKI (AUC=0.83; CI=0.75-0.89), compared with eGFR (AUC=0.67; 95% CI=0.59-0.75), p=0.003 and NT-proBNP (AUC=0.62; CI=0.51-0.72), p0.001. Pre-operative GDF-15 was also significantly better than the EuroSCORE in predicting AKI (AUC 0.62, 95% CI=0.54-0.70), p0.001.Pre-operative GDF-15 plasma levels are associated with post-operative AKI in CABG patients. If confirmed in larger cohorts, pre-operative GDF-15 may be of value to improve pre-operative risk stratification among candidates for surgery.