Late Postoperative Atrial Fibrillation Research Articles

Postoperative atrial fibrillation burden and progression patterns after cardiac surgery during 2.5 years of continuous rhythm monitoring

Abstract Background Early postoperative atrial fibrillation (POAF) is a frequent complication after cardiac surgery, with an incidence of up to 50%.(1, 2) The clinical presentation of early-POAF, however, might be highly diverse, showing great individual differences in symptoms, as well as POAF-specific characteristics such as the number of episodes, duration of episodes, and the percentage of time spent in POAF (POAF-burden). It is currently unknown how these early-POAF characteristics, particularly POAF-burden, are related to the risk of developing late-POAF recurrences. Purpose To establish the association between early-POAF characteristics, in particular POAF-burden, and late-POAF occurrence and burden. Methods Patients with and without a history of AF undergoing cardiac surgery were included. Preoperatively, all patients underwent echocardiography, electrocardiography, and blood biomarker analysis. Intraoperatively, all patients received an implantable loop recorder for a period of 2.5 years. POAF was defined as an AF episode lasting at least 2 minutes, detected by the ILR algorithm, and all episodes were manually checked by the investigators. POAF-burden was calculated as the percentage of time in AF for different time intervals (early: 0-3 months, late: 3-30 months). Classification of burden was performed based on cut-off values for tertiles. Also, associations between early-POAF characteristics, such as episode duration, and the incidence of late-POAF were analyzed. Results The study population consisted of 98 patients undergoing cardiac surgery (71 without preoperative AF history and 27 with preoperative AF history), out of which 53 developed POAF. Early-POAF occurred in 46 patients, and late-POAF in 36 patients. Early-POAF was associated with an increased occurrence of late POAF after adjusting for age, sex, PAF-history, and persistent AF-history (adjusted hazard ratio [aHR] = 4.62, 95% CI: 1.93-11.05, p<0.001) (Figure 1A). Multiple regression analysis, adjusted for age, sex, PAF-history, and persistent AF-history, revealed a gradual increase in late-POAF hazard between the early-POAF burden tertiles compared to patients without early-POAF (p<0.001) (Figure 1B). Similarly, the longest individual early-POAF episode and the number of early-POAF episodes were both associated with an increased late-POAF hazard (p<0.001 and p<0.001, respectively) (Figure 1C-D). The highest POAF-burden was observed in the early postoperative phase, with a significant reduction in the late phase (p=0.007) (Figure 2A). Overall, 84 patients had no late-POAF or a reduction in POAF burden, while 14 patients showed an increase in POAF-burden compared to the early postoperative phase (Figure 2B). Conclusion Early-POAF characteristics, such as POAF-burden, are strongly associated with an increased occurrence of late-POAF. The highest POAF-burden is present in the early postoperative phase, and only a minority of patients experience an increase in late-POAF burden.Figure 1Figure 2

Increased circulating BMP10 levels are associated with late postoperative atrial fibrillation after cardiac surgery and left atrial endomysial fibrosis

Abstract Background Serum bone morphogenetic protein 10 (BMP10) levels are a marker for history of atrial fibrillation (AF) and for major adverse cardiovascular events in AF-patients, including stroke, recurrence after catheter ablation, and mortality. The predictive value of BMP10 in patients undergoing cardiac surgery and association with morphological properties of atrial tissue are unknown. Objective To study the correlation between BMP10 levels and pre-operative clinical traits, occurrence of early and late postoperative atrial fibrillation (POAF), and atrial fibrosis in patients undergoing cardiac surgery. Methods Patients with and without preoperative AF history undergoing first cardiac surgery were included (RACE V, n=147). Pre-operative blood biomarkers were analyzed, left (n=114) and right (n=125) atrial appendage biopsies were histologically assessed following WGA-staining, and post-operative rhythm was monitored continuously with implantable loop recorders (n=134, 2.5yrs). Results Multiple logistic regression indicated that BMP10 accurately predicts a history of persistent AF (OR=1.24, 95%CI: 1.10-1.40, p=4.32e-4), similar to NT-pro-BNP. BMP10 levels were associated with increased late-POAF90 occurrence after adjusting for age, sex, AF history, and early-POAF occurrence (HR=1.07 [per 0.1ng/ml increase], 95%CI: 1.00-1.14, p=0.04). Left atrial endomysial fibrosis (St.β=0.22, p=0.04), but not overall fibrosis (St. β= , p=), was associated with circulating BMP10, after adjusting for age, sex, AF history, reduced LVF, and valvular surgery indication. Conclusion Increased BMP10 levels were associated with persistent AF-history, increased late-POAF incidence, and LAA endomysial fibrosis in a diverse population of patients undergoing cardiac surgery.

Circulating BMP10 Levels Associate With Late Postoperative Atrial Fibrillation and Left Atrial Endomysial Fibrosis

BackgroundSerum bone morphogenetic protein 10 (BMP10) blood levels are a marker for history of atrial fibrillation (AF) and for major adverse cardiovascular events in patients with AF, including stroke, AF recurrences after catheter ablations, and mortality. The predictive value of BMP10 in patients undergoing cardiac surgery and association with morphologic properties of atrial tissues are unknown. ObjectivesThis study sought to study the correlation between BMP10 levels and preoperative clinical traits, occurrence of early and late postoperative atrial fibrillation (POAF), and atrial fibrosis in patients undergoing cardiac surgery. MethodsPatients with and without preoperative AF history undergoing first cardiac surgery were included (RACE V, n = 147). Preoperative blood biomarkers were analyzed, left (n = 114) and right (n = 125) atrial appendage biopsy specimens were histologically investigated after WGA staining, and postoperative rhythm was monitored continuously with implantable loop recorders (n = 133, 2.5 years). ResultsAdjusted multinomial logistic regression indicated that BMP10 accurately reflected a history of persistent AF (OR: 1.24, 95% CI: 1.10-1.40, P = 0.001), similar to NT-pro-BNP. BMP10 levels were associated with increased late POAF90 occurrence after adjustment for age, sex, AF history, and early POAF occurrence (HR: 1.07 [per 0.1 ng/mL increase], 95% CI: 1.00-1.14, P = 0.041). Left atrial endomysial fibrosis (standardized β = 0.22, P = 0.041) but not overall fibrosis (standardized Β = 0.12, P = 0.261) correlated with circulating BMP10 after adjustment for age, sex, AF history, reduced LVF, and valvular surgery indication. ConclusionsIncreased BMP10 levels were associated with persistent AF history, increased late POAF incidence, and LAA endomysial fibrosis in a diverse sample of patients undergoing cardiac surgery.

Benefits of On-X Mitral Valve Replacement in Cases of Infective Endocarditis

Purpose. Mitral valve replacement (MVR) is necessary in cases of severe infective endocarditis (IE). Because the On-X valve is expected to be effective in reducing prosthesis-associated turbulent blood flow, we investigated the hemodynamic efficacy of the On-X valve when used for MVR in cases of mitral valve IE. Methods. We compared postoperative outcomes between two groups of patients who underwent MVR for IE: 13 given an On-X valve and 27 given an SJM valve. Results. There were no in-hospital deaths. Late death occurred in 6 cases, all in the SJM group (P=0.1520). The incidence of late postoperative atrial fibrillation was relatively low in the On-X group (1 case vs. 10 cases, P=0.068). Univariate analysis showed an association between the effective orifice area and postoperative atrial fibrillation. The effective orifice area and indexed effective orifice area were significantly larger in the On-X group at 2.8 ± 0.7 cm2 vs. 2.2 ± 0.5 cm2 (P=0.007) and 1.8 ± 0.5 cm2/m2 vs. 1.4 ± 0.4 cm2 (P=0.003), respectively. Conclusions. The suggested reduction in left atrial load attributed to the use of the On-X valve in MVR for IE may reduce the incidence of postoperative atrial fibrillation.

Left atrial function and not volume predicts mid-to-late atrial fibrillation after mitral valve repair.

Patients undergoing surgical mitral valve repair (MVr) for degenerative mitral regurgitation are at risk of even late postoperative atrial fibrillation (AF). Left atrial (LA) function has been shown superior to LA volume in evaluating the risk of AF in diverse cardiac conditions. We therefore investigated the prognostic value of LA function and volume in predicting mid-to-late postoperative AF after MVr (>30 days postoperatively). We retrospectively identified all patients who underwent MVr for degenerative mitral regurgitation between 2012 and 2019 at our institution. Exclusion criteria were preoperative AF, concomitant procedures, re-operations, missing or insufficiently processable preoperative echocardiograms and missing follow-up. LA function and volume measurements were conducted using speckle-tracking strain echocardiographic analysis. Postoperative LA function was measured in a subgroup with sufficient postoperative echocardiograms. We included 251 patients, of whom 39 (15.5%) experienced AF in the mid-to-late postoperative period. Reduced LA strain parameters and more than mild preoperative tricuspid regurgitation were independently associated with mid-to-late postoperative AF. LA volume index had no association with mid-to-late postoperative AF in univariable analysis and did not improve the performance of multivariable models. Patients with mid-to-late AF exhibited diminished improvement in LA function after surgery. In MVr patients, LA function (but not volume) showed independent predictive value for mid-to-late postoperative AF. Including LA function into surgical decision-making and approach may identify patients who will benefit from earlier intervention with the aim to prevent irreversible LA damage with consequent risk of postoperative AF.

Characterization of pre-existing arrhythmogenic substrate associated with de novo early and late postoperative atrial fibrillation

BackgroundPoAF is the most common complication after cardiac surgery and may occur in patients with pre-existing arrhythmogenic substrate. Characterization of this substrate could aid in identifying patients at risk for PoAF. We therefore compared intra-atrial conduction parameters and electrogram morphology between patients without and with early- (≤5 days after surgery) and late- (up to 5 years) postoperative atrial fibrillation (PoAF). Methods and resultsEpicardial mapping of the right and left atrium and Bachmann's Bundle (BB) was performed during sinus rhythm (SR) in 263 patients (207male, 67 ± 11 years). Unipolar potentials were classified as single, short or long double and fractionated potentials. Unipolar voltage, fractionation delay (time difference between the first and last deflection), conduction velocity (CV) and conduction block (CB) prevalence were measured. Comparing patients without (N = 166) and with PoAF (N = 97), PoAF was associated with lower CV and more CB at BB. Unipolar voltages were lower and more low-voltage areas were found at the left and right atrium and BB in PoAF patients. These differences were more pronounced in patients with late-PoAF (6%), which could even occur up to 5 years after surgery. Although several electrophysiological parameters were related to PoAF, age was the only independent predictor. ConclusionsPatients with de novo PoAF have more extensive arrhythmogenic substrate prior to cardiac surgery compared to those who remained in SR, which is even more pronounced in late-PoAF patients. Future studies should evaluate whether intra-operative electrophysiological examination enables identification of patients at risk for developing PoAF and hence (preventive) therapy.

Abstract 14196: Early Postoperative Atrial Fibrillation Combined With Preoperative Structural and Electrophysiological Parameters Are Good Predictors of Late Postoperative Atrial Fibrillation in Patients Undergoing Cardiac Surgery

Introduction: Atrial fibrillation (AF) in the early postoperative phase (E-POAF) is likely caused by a combination of an arrhythmogenic substrate and surgery-induced stressors. Although E-POAF is regarded as a transient arrhythmia, recent findings suggest that patients with E-POAF also show late AF recurrences. The aim of this study is to determine the incidence of late postoperative AF (L-POAF) within 1 year of cardiac surgery and to identify its predictors. Hypothesis: The occurrence of L-POAF is associated with preexisting functional and structural atrial changes, and with occurrence of E-POAF. Methods: Ninety-two patients without history of AF undergoing first cardiac surgery were prospectively included. Intraoperatively, all patients received an implantable loop recorder (Reveal LINQ, Medtronic, USA) for continuous rhythm monitoring. Preoperative transthoracic echocardiograms (TTE), 12-lead electrocardiograms (ECG), blood samples, and clinical data were analyzed. Results: Eighty-five patients completed 1-year of follow-up. Incidence of L 5 -POAF (AF between 5-365 days after surgery) was 31.8%, whereas incidence of L 30 -POAF (AF between 30-365 days after surgery) was 15.3%. Independent predictors for L 5 -POAF were left atrial maximum volume indexed for body surface area (LAVi) and occurrence of E 5 -POAF (p=0.02, p<0.01, respectively). Independent predictors for L 30 -POAF were PR-interval and occurrence of E 30 -POAF (p=0.02, p=0.01, respectively). Predictive models for L-POAF based on TTE, biomarkers, and ECG showed moderate performance while addition of E-POAF strongly improved sensitivity and specificity (L 5 -POAF: 94.1% & 95.2%; L 30 -POAF: 83.3% & 91.0%, respectively) to predict L-POAF (see figure). Conclusion: Predictive models based on preoperative LAVi, increased PR-interval, and occurrence of E-POAF show excellent diagnostic accuracy for predicting occurrence of L-POAF.

Postoperative Atrial Fibrillation or Flutter Following Transcatheter or Surgical Aortic Valve Replacement: PARTNER 3 Trial.

The aim of this study was to assess the incidence and prognostic impact of early and late postoperative atrial fibrillation or flutter (POAF) in patients with severe aortic stenosis (AS) treated with transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR). There is an ongoing controversy regarding the incidence, recurrence rate, and prognostic impact of early (in-hospital) POAF and late (postdischarge) POAF in patients with AS undergoing TAVR or SAVR. In the PARTNER (Placement of Aortic Transcatheter Valve) 3 trial, patients with severe AS at low surgical risk were randomized to TAVR or SAVR. Analyses were performed in the as-treated population excluding patients with preexistent atrial fibrillation or flutter. Among 781 patients included in the analysis, early POAF occurred in 152 (19.5%) (18 of 415 [4.3%] and 134 of 366 [36.6%] following TAVR and SAVR, respectively). Following discharge, 58 new or recurrent late POAF events occurred within 1 year following the index procedure in 55 of 781 patients (7.0%). Early POAF was not an independent predictor of late POAF following discharge (odds ratio: 1.04; 95% CI: 0.52-2.08; P=0.90). Following adjustment, early POAF was not an independent predictor of the composite outcome of death, stroke, or rehospitalization (hazard ratio: 1.10; 95%CI: 0.64-1.92; P=0.72), whereas late POAF was associated with an increased adjusted risk for the composite outcome (hazard ratio: 8.90; 95%CI: 5.02-15.74; P< 0.0001), irrespective of treatment modality. In the PARTNER 3 trial, early POAF was more frequent following SAVR compared with TAVR. LatePOAF, but not early POAF, was significantly associated with worse outcomes at 2 years, irrespective of treatmentmodality.

Left Atrial Mechanical Function Predicts Postoperative AF in Patients with Rheumatic Mitral Valve Disease Who Underwent Mitral Valve Surgery.

Postoperative atrial fibrillation (PoAF) is a common complication after surgical mitral valve replacement. Late PoAF is independently associated with long-term mortality. This study aimed to test the utility of preoperative left atrial mechanical function as a predictor of early and late PoAF in clinical practice. Patients (N = 150) with a rheumatic mitral valve who underwent mitral valve replacement with or without tricuspid valvuloplasty and who were in stable sinus rhythm were included. Baseline characteristics and transthoracic echocardiographic assessment information on the day before surgery were collected. Em, Em´, and Ei´ indicate early diastolic peak velocity of the mitral valve, early diastolic velocity at the lateral wall of the mitral annulus, and early diastolic velocity at the interventricular septal annulus, respectively. Early PoAF was present in 59 of 150 patients (39.3%), and 32 of 150 patients (21.3%) developed late PoAF within 1 year after surgery. Among all of the variables examined, age, diabetes, early mitral filling velocity (Mitral E), left atrial mechanical function (Mitral A), Em/Em´, Em/Ei´, and mitral transvalvular gradient showed a significant correlation with PoAF. Only age, Mitral A, and mitral transvalvular gradient showed strong, significant correlations with the occurrence of late PoAF. In a multivariate analysis, predictors of late PoAF recurrence included early PoAF and Mitral A. Routine evaluation of Mitral A is feasible and useful to predict early and late PoAF in patients with a rheumatic mitral valve undergoing surgical mitral valve replacement.

Early and late post-operative arrhythmias after surgical myectomy: 45 years of follow-up

AimsThe aims of this study are to investigate the incidence and determinants of post-operative atrial arrhythmias, conduction disorders and mortality in hypertrophic obstructive cardiomyopathy (HOCM) patients undergoing transaortic myectomy. Methods and resultsThis retrospective single-center study was conducted in 249 patients (median age 54 years [40–64], 42% female) undergoing transaortic myectomy. Post-operative atrial fibrillation (AF) was reported in 84 patients (33.7%), including 56 patients (22.5%) with de novo AF. Older age (HR = 1.027 (1.003–1.052), p = 0.029) and hypercholesterolemia (HR = 2.296 (1.091–4.832) p = 0.029) were independent predictors for de novo post-operative AF. Late post-operative AF and atrial flutter (AFL) occurred in 18.9% and 6.8% of the patients, respectively. De novo early post-operative AF increased the risk of late post-operative AF (HR = 3.138 (1.450–6.789), p = 0.004). Patients with a right bundle branch block had a higher risk of early-postoperative pacemaker implantation (p = 0.003, HR = 9.771 (2.195–43.505)). Higher age at time of surgery (HR = 1.053 (1.026–1.081), p < 0.001) was a predictor for late mortality (n = 47, 18.9%). ConclusionEarly and late post-operative AF, AFL and other SVTs are common sequelae after myectomy and are associated with older age at surgery, history of AF and early post-operative AF. Early post-operative arrhythmias are not transient and periodic rhythm monitoring is therefore essential to initiate therapy as soon as possible.

Progression of late postoperative atrial fibrillation in patients with tetralogy of Fallot.

ToF patients are at risk for ventricular deterioration at a relatively young age, which can be aggravated by AF development. Therefore, knowledge on AF development and its timespan of progression is essential to guide treatment strategies for AF. We examined late postoperative AF onset and progression in ToF patients during long-term follow-up after ToF correction. In addition, coexistence of AF with regular supraventricular tachyarrhythmias (SVT) and ventricular tachyarrhythmias (VTA) was analyzed. ToF patients (N=29) with AF after ToF correction referred to the electrophysiology department between 2000 and 2015 were included. All available rhythm registrations were reviewed for AF, regular SVT, and VTA. AF progression was defined as transition from paroxysmal AF to (longstanding) persistent/permanent AF or from (longstanding) persistent AF to permanent AF. At the age of 44 ± 12 years, ToF patients presented with paroxysmal (N=14, 48%), persistent (N=13, 45%) or permanent AF (N=2, 7%). Age of AF development was similar among patients who either underwent initial shunt creation (N=15, 45 ± 11 [25-57] years) or primary total ToF correction (N=14, 43 ± 13 [26-66] years) (P=0.785). AF coexisted with regular SVT (N=18, 62%) and VTA (N=13, 45%). Progression of AF occurred in 11 patients (38%) within 5 ± 5 years after AF onset despite antiarrhythmic drug class II (AAD, P=0.052) or III (P=0.587) usage. AF in our ToF population developed at a young age and showed rapid progression. Rhythm control by pharmacological therapy was ineffective in preventing AF progression.

A prospective randomized controlled trial on the incidence and predictors of late-phase postoperative atrial fibrillation up to 30 days and the preventive value of biatrial pacing

Postoperative atrial fibrillation (POAF) is considered to be a transient arrhythmia in the first week after cardiac surgery. To determine the 30-day incidence and predictors of POAF and the value of postoperative overdrive biatrial pacing in the prevention of POAF. Patients (n = 148) without a history of atrial fibrillation undergoing aortic valve replacement or coronary artery bypass graft (CABG) were randomized into a pacing group (n = 75) and a control group. Patients were treated with standardized sotalol postoperatively. Rhythm was continuously monitored for 30 days by a transtelephonic event recorder. POAF occurred in 73 (49.3%) patients, of whom 60 (40.5%) patients showed POAF during postoperative days (PODs) 0-5 and 37 (25%) patients during PODs 6-30. Prolonged aortic cross-clamp time was an important univariate predictor of 30-day and of late POAF (PODs 6-30; P = .017 and P = .03, respectively). Best-fit model analysis using 15 predetermined risk factors for POAF showed different positive interactive effects for early POAF (ie, baseline C-reactive protein levels with a history of myocardial infarction or low body mass index) and late POAF (ie, high body mass index, diabetes mellitus, baseline C-reactive protein, early POAF, creatinine levels, type of operation, smoking, and male gender). Biatrial pacing reduced the late POAF incidence in patients with aortic cross-clamp time >50 minutes (P = .006). POAF is not limited to the first week after cardiac surgery but also occurs frequently in the postoperative month. It is desirable to regularly follow patients with POAF for atrial fibrillation recurrences after discharge.

Late postoperative atrial fibrillation after cardiac surgery: a national survey within the cardiac rehabilitation setting

The aims of this study were to determine the incidence and clinical predictors of new-onset and recurrent late postoperative atrial fibrillation (POPAF) in a large cohort of patients who underwent cardiac rehabilitation programs (CRPs) after discharge from surgery units, and the association between late POPAF and cardiovascular morbidity and mortality in the medium term. The ISYDE and ICAROS registries were two multicenter, prospective studies carried out by the Italian Association for Cardiovascular Prevention, Rehabilitation and Epidemiology (IACPR-GICR), providing clinical information on consecutive patients completing CRP in 165 facilities. Patients following cardiac surgery were considered, with the exclusion of those with persistent POPAF at discharge from the surgery units. A total of 2256 patients following cardiac surgery were enrolled (isolated coronary surgery 62.9%, valve interventions 16%, combined surgery 21.1%). The mean age of patients was 67 ± 10 years, and the observation period 13 ± 20 days. During CRP, POPAF occurred in 241 (10.7%) patients, with 4.4% new-onset and 6.3% recurrent cases, respectively. In the logistic regression model, valve surgery (P < 0.05), a history of early POPAF (P < 0.001), and the presence of postoperative ventricular arrhythmias (P < 0.05) independently predicted the occurrence of late POPAF. Lack of prescription of cardioprotective drugs was not associated with late POPAF. Late POPAF increased the 1-year risk of cardiovascular events after CRP, mainly episodes of decompensated heart failure. A high level of suspicion for late POPAF, after discharge from surgery units, should be maintained due to the risk of occurrence, the low antiarrhythmic effect of common cardioprotective drugs and the impact on cardiovascular prognosis.

Late postoperative atrial fibrillation: minor surgery complication or major cardiovascular issue?

Clinica di Cardiologia, Università Politecninca delle Marche, Ancona, Italy Correspondence to Alessandro Capucci, MD, Clinca di Cardiologia, Università Politecnica delle Marche, Conca 71, Ancona 60131, Italy Tel: +39 0715 965 440; fax: +39 0715 965 624; e-mail: [email protected]

Surgery for Permanent Atrial Fibrillation: Impact of Patient Factors and Lesion Set

Whether a complete Cox-maze procedure is needed to ablate permanent atrial fibrillation in patients undergoing concomitant cardiac surgery is unknown. Our objective was to assess the effectiveness of different lesion sets in such patients. From November 1991 to January 2004, 575 patients underwent surgical treatment of permanent atrial fibrillation (duration > 6 months); mitral valve disease was the primary indication for surgery in 74%. Procedures included pulmonary vein isolation alone (n = 68, 12%), pulmonary vein isolation with left atrial connecting lesions (n = 265, 46%), and Cox-maze (n = 242, 42%). Rhythm documented on 5,120 postoperative electrocardiograms was used to estimate time-related prevalence of, and risk factors for, atrial fibrillation. Prevalence of postoperative atrial fibrillation peaked at 46% two weeks after operation, declining to 24% at one year. Patient-related risk factors for increased prevalence included older age (p < 0.0001), larger left atrium (p < 0.0001), and longer duration of preoperative atrial fibrillation (p = 0.0008). The Cox-maze procedure and lesion sets resembling it created with alternative energy sources had a similarly low prevalence of late postoperative atrial fibrillation; in contrast, pulmonary vein isolation and lesion sets that did not include a lesion to the mitral anulus were less effective. This study suggests that in cardiac surgical patients with permanent atrial fibrillation the left atrial lesion set should include wide pulmonary vein isolation, at least one connection between right and left pulmonary veins, and a connection to the mitral anulus. Availability of alternative energy sources to create lesions sets has virtually eliminated the need for the cut-and-sew Cox-maze procedure.

Atrial Natriuretic Peptide Predicts Impaired Atrial Remodeling and Occurrence of Late Postoperative Atrial Fibrillation after Surgery for Symptomatic Aortic Stenosis

Background: Aortic stenosis (AS) and atrial fibrillation (AF) are commonly encountered in clinical practice. Natriuretic peptides (NP) are endogenous cardiac hormones, which have been shown to increase in patients with heart failure, and valvular or congenital heart disease. We aimed to determine the association between atrial NP (ANP) and late postoperative AF after surgery for AS along with temporal changes in plasma ANP levels and left atrial (LA) volumes. Methods: 22 patients (16 males/6 females, mean age: 61 years) with symptomatic AS and 8 healthy volunteers (5 males/3 females) were enrolled into our study. All the patients studied underwent transthoracic echocardiography, which was repeated during the follow-up. N-terminal ANP (N-ANP) was studied initially and at the 2-month follow-up. Postoperatively, the patients were followed up for 12 months for AF attacks. Results: Patients with AS had significantly higher levels of N-ANP, left ventricular (LV) end-diastolic pressure, E/A ratio, LV mass and LA volumes compared to the controls. Patients with postoperative AF attacks were significantly older, had higher N-ANP levels and LV end-diastolic pressure in addition to higher LA volumes and longer symptom duration compared to patients without AF. Age at the time of operation (p = 0.011) and N-ANP at the 2nd month (p = 0.047) were found to be independent predictors for late AF attacks during follow-up in regression analysis. Besides, N-ANP (p < 0.001) at the 2-month follow-up independently predicted impaired LA remodeling. Conclusion: ANP might be an important factor to identify AS patients at risk for late postoperative AF attacks.