Risk Of Atrial Fibrillation Occurrence Research Articles

Predictive value of NT pro BNP for new-onset atrial fibrillation in heart failure and preserved ejection fraction.

The prognostic significance of N-terminal pro B-type natriuretic peptide (NT-proBNP) in heart failure with preserved ejection fraction (HFpEF) has been well established. HFpEF and atrial fibrillation (AF) commonly coexist, and each contributes to poor outcomes independently. Nevertheless, the ability of NT-proBNP to predict AF in HFpEF patients remains uncertain. A total of 367 HFpEF patients without baseline AF from the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial were included. The Cox proportional hazard model was used to assess the association of NT-proBNP with the risk of AF. The C-statistic, categorical net reclassification index (NRI), and integrated discrimination improvement (IDI) were used to evaluate the ability of NT-proBNP in new-onset AF prediction. During a median follow-up of 2.91years, 17 (4.63%) new-onset AF cases occurred. Every 1000pg/mL increase in NT-proBNP was associated with a 16% increase in the risk of AF occurrence after adjustments (hazard ratio, 1.16 [95% CI, 1.02-1.32]). NT-proBNP showed a moderate performance for new-onset AF at 3years (C-statistic, 0.67). Adding NT-proBNP to CHADS2/R2CHADS2/CHA2DS2-VASc/C2HSET scores improved their predictive performance for AF risk (CHADS2: C-statistic, 0.63, CHADS2+NT: C-statistic, 0.69, NRI, 47.46%, IDI, 1.18%; R2CHADS2: C-statistic, 0.65, R2CHADS2+NT: C-statistic, 0.70, NRI, 48.03%, IDI, 0.51%; CHA2DS2-VASc: C-statistic, 0.67, CHA2DS2-VASc+NT: C-statistic, 0.72, NRI, 49.41%, IDI, 0.86%; C2HSET: C-statistic, 0.77, C2HSET+NT: C-statistic, 0.80, NRI, 50.32%, IDI, 1.58%). Among patients with HFpEF, the NT-proBNP level was positively associated with the incidence of new-onset AF and may be a promising predictor.

Long-term time-course of atrial sensing and incidence of atrial fibrillation in patients with VDD versus DDD pacemakers

Abstract Introduction VDD pacemakers (PM) theoretically have the same advantages with respect to maintaining atrioventricular (AV) synchrony as dual-chamber (DDD) pacemakers, with lower costs and simpler implantation procedure. However, their use is often limited by concerns about the maintenance of atrial sensing (AS) and the occurrence of atrial fibrillation (AF). Purpose We aimed to compare long-term atrial sensing stability, the incidence of AF and complications in VDD and DDD systems. Methods We retrospectively enrolled patients who underwent VDD or DDD PM implantation for AV block between 2014 and 2021 from 2 centers. Clinical, analytical and electrical variables at implantation, their evolution and events at follow-up (25.2±16.2 months) were collected, comparing the groups by Kaplan-Meier and Cox multivariate analysis. Results 487 patients who underwent PM implantation were included, 189 (38,8%) received a VDD PM and 298 (61,2%) a DDD PM. Patients with VDD were older and had a higher prevalence of risk factors and lower atrial voltage at implantation (Table). Complications at implantation and early complications were scarce and without significant differences in both groups. During follow-up, there was a reduction in atrial voltage in the VDD group (implant 1.4+0.8 mV; follow-up 1.2+0.9 mV; p<0.01), with stability in the DDD group (3.8+2.1 vs 3.9+2.2 mV). Total percentages of AS loss were 23.2% (VDD) vs 2.3% (DDD); p<0.01) (Figure 1). In the Cox multivariate analysis the risk of late AS loss was higher in the VDD group (HR=7.6; 95% CI 2.86-20.3; p<0.001) together with the AS values at implant (HR=0.72; 95% CI 0.52-1.00; p=0.052). AS loss was corrected with reprogramming in 23 patients, reintervention was needed in 1 (2%) and VVI was abandoned in 27 (53%). The risk of AF occurrence was lower in the VDD group (HR=0.39 CI 95% 0.18-0.87; p=0.021) (Figure 2). Conclusions In the long term, AS is significantly reduced in VDD MPs, leading to its loss in a quarter of VDD patients. It is usually correctable with reprogramming, rarely requiring abandonment to VVI. AS at implantation is crucial as it is directed related to the AS during follow-up. DDD PMs were independently associated with a higher incidence of AF, with no differences in the remaining complications.TableFigure

Association between types of antihypertensive medication and the risk of atrial fibrillation: a nationwide population study.

Patients with hypertension are at a high risk of atrial fibrillation (AF). Recent research has indicated the varying effects of antihypertensive medications on developing AF. We investigated the relationship between different types of antihypertensive medications and the risk of AF occurrence. We analyzed data from 113,582 subjects with national health screening examinations between 2009 and 2014. The study population was categorized according to antihypertensive medication type. The primary outcome was the incidence of AF. Among 113,582 subjects (mean age 59.4 ± 12.0 years, 46.7% men), 93,557 received monotherapy [angiotensin receptor blockers (ARB), angiotensin-converting enzyme inhibitors (ACEi), beta-blockers, calcium channel blockers (CCB), or diuretics], while 34,590 received combination therapy (ARB/beta-blockers, ARB/CCB, ARB/diuretics, or ARB/CCB/diuretics). During a mean follow-up duration of 7.6 ± 2.1 years, 3.9% of patients were newly diagnosed with AF. In monotherapy, ACEi and CCB had similar AF risks as ARB, while beta-blockers and diuretics showed higher AF risks than ARB. In combination therapy, ARBs/CCBs and ARBs/diuretics had the lowest AF risk, whereas ARBs/beta-blockers had the highest compared to ARB/CCB. Among the specific ARBs, the AF risk varied insignificantly, except for telmisartan and candesartan. In hypertensive patients receiving monotherapy, ACEi and CCB showed a similar AF risk as ARBs, while beta-blockers and diuretics were associated with a higher risk. Among those receiving combination therapy, ARBs/CCBs and ARBs/diuretics had the lowest AF risk, whereas ARBs/beta-blockers showed the highest risk. Various types of ARBs have different associations with AF risk.

Thyroid gland dysfunction in heart rhythm disorders

Thyroid gland dysfunction is estimated to occur in approximately 5% of the population and affects people of different ages. Cardiovascular diseases can occur in diseases such as hyperthyroidism as well as hypothyroidism. Increased thyroid hormone levels precipitate sympathetic nervous system activation, potentially culminating in heightened heart rate (tachycardia) and disruptions in electrical conduction. This influence can induce QT interval shortening and provoke premature ventricular contractions (PVCs), amplifying the propensity for more severe arrhythmic manifestations. Insufficiency of thyroid hormones decelerates metabolic activity, potentially leading to bradycardia. Hypothyroidism elevates the risk of atrial fibrillation occurrence and additionally elongates QT intervals, enhancing the susceptibility to torsade de pointes. Untreated hormone disorders affect severe cardiac complications, which can occur in patients with previously diagnosed heart disease. Effective management of cardiac arrhythmias in patients with thyroid dysfunction necessitates interdisciplinary collaboration between endocrinologists and cardiologists.

POSSIBLE PREDICTORS CONTRIBUTING TO ATRIAL FIBRILLATION OCCURRENCE IN HYPERTENSIVE PATIENTS

Objective: Arterial hypertension (HT) and atrial fibrillation (AF) are two important public health problems. Their prevalence is increasing worldwide, and often coexist in the same patient. HT and AF are strikingly related to an excess risk of cardiovascular disease and death. HT ultimately increases the risk of AF and several factors underlying the higher risk of AF in patients with HT are still incompletely known. HT is one of the main reasons for the remodeling process in and makes a significant contribution to the development of structural changes of the heart. The aim of this study is to identify possible predictors of paroxysmal/persistent AF occurrence and progression in hypertensive patients. Design and method: In this study where enrolled 219 hypertensive patients with non-valvular paroxysmal/persistent AF (mean age 63.6±7.4). As a control group 94 patients with HT and without AF were also examined. Echocardiography examination and 24-hour ambulatory Holter monitoring ECG were registered in each patient. The database consisting of 19 indicators that characterize the clinical, hemodynamic and structural-functional state of the heart, as well as markers of inflammation and fibrosis was created. Data were analyzed by SPSS 13 program using logistic analysis by odds ratio (OR). Results: The obtained results showed that in hypertensive patients with paroxysmal/persistent AF, OR of more episodes of hypertensive crises, deterioration of electrical remodeling and left ventricular (LV) diastolic function, as well as a significant increase in the levels of concentrations of inflammatory and fibrosis markers in comported with hypertensive patients without AF were detected. Conclusions: The multifactorial analysis revealed significant impact of LA and LV dysfunction, inflammation and fibrosis as well as hypertensive crises on the possible risk of AF occurrence and progression in hypertensive patients.

POSSIBLE PREDICTORS CONTRIBUTING TO AF OCCURRENCE IN HYPERTENSIVE PATIENTS

Objective: Arterial hypertension (AH) and atrial fibrillation (AF) are two important public health problems. Their prevalence is increasing worldwide, and often coexist in the same patient. AH and AF are strikingly related to an excess risk of cardiovascular disease and death. AH ultimately increases the risk of AF and several factors underlying the higher risk of AF in hypertensive patients are still incompletely known. AH is one of the main reasons for the remodeling process in these patients and makes a significant contribution to the development of structural changes. The aim of this study is to identify possible predictors of paroxysmal/persistent AF occurrence and progression in hypertensive patients Design and method: In this study where enrolled 219 hypertensive patients with non-valvular paroxysmal/persistent AF (mean age 63.6 ±7.4) who were hospitalized at Research Institute of Cardiology between 2016 and 2018 year. As a control group 94 hypertensive patients without AF were also examined. After the enrollment the echocardiography examination and 24-hour ambulatory Holter monitoring ECG were registered in each patient. We measured plasma indexes of inflammation (hsCRP, IL-6) and fibrosis marker TGF-beta1. The database consisting of 19 indicators that characterize the clinical, hemodynamic and structural-functional state of the heart, as well as markers of inflammation and fibrosis was created. All data were analyzed by SPSS 13 and EXCEL - 2013 programs using logistic analysis by odds ratio (OR). Results: The obtained results showed that in hypertensive patients with paroxysmal /persistent AF, OR of more episodes of hypertensive crises, deterioration of electrical remodeling and LV diastolic function, as well as a significant increase in the levels of concentrations of inflammatory and fibrosis markers in comported with hypertensive patients without AF were detected (tabl.1). Conclusions: The multifactorial analysis revealed significant impact of left atrial and ventricular dysfunction, inflammation and fibrosis as well as hypertensive crises on the possible risk of AF occurrence and progression in hypertensive patients

Aggravated Gut Microbiota and Metabolomic Imbalances Are Associated with Hypertension Patients Comorbid with Atrial Fibrillation.

Disordered gut microbiota (GM) as the co-contributor of atrial fibrillation (AF) and hypertension (HTN) might be associated with AF risk in HTN. This study aimed to explore the altered GM community and metabolic patterns between 27 HTN patients with AF (HTN-AF) and 27 non-AF HTN patients through fecal metagenomic and serum metabolomic analysis. Compared to non-AF HTN patients, significant microbial alterations (p = 0.004), including increased microbial diversity (p < 0.05), shifted enterotype dominated by Prevotella to Bacteroides, and abundant disease-linked genera Ruminococcus, Streptococcus, Veillonella, Dorea, and Enterococcus, were observed in HTN-AF patients. A species-based random forest prediction model was associated with the risk of AF occurrence in HTN patients. Furthermore, GM metabolic profiles dramatically differed between HTN and HTN-AF patients, especially the imbalance of saturated and unsaturated fatty acids. In HTN-AF patients, circulating palmitic acid and arachidonic acid levels were significantly elevated, while the levels of tetracosahexaenoic acid, oleic acid, linoleic acid, and stearic acid were decreased (p < 0.001, VIP > 1), mediating 85.99% of gut microbial indirect effects on AF (p < 0.001). Thus, our findings preliminarily indicated that exacerbated dysbiosis of GM and relevant metabolites was associated with high AF susceptibility and might be a potential target for AF prediction and prevention in HTN.

Risk of atrial fibrillation in hypertrophic cardiomyopathy: a clustering analysis based on the French registry on hypertrophic cardiomyopathy (REMY)

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): CHU Rennes, Inserm, LTSI – UMR 1099, F-35000 Rennes, France Assistance Publique-Hôpitaux de Paris-Centre Université de Paris, University of Paris onbehalf REMY register Paroxysmal or chronic atrial fibrillation (AF) is frequent in hypertrophic cardiomyopathy (HCM),(20%-25% of patients), and is often considered as an important disease turning point. The aim of this study is to determine HCM-phenogroups with different risk of AF-occurrence at 5-year. We applied the Bayesian method to differentiate phenogroups of patients with different risks of AF across a French hospital registry of adult HCM(REMY). Data were prospectively recorded on 5 years follow-up. 1431 HCM patients were recruited, including 1275 analyzed. The population included 412 women. AF-occurred in 167 (11.6%) patients. 3 phenogroups were defined according to their common characteristics. Patients at the highest risk were more often female, with more frequent comorbidities, greatest anteroposterior LA diameter, diastolic dysfunction, outflow-tract obstruction or mitral valve abnormality, and presented higher sPAP or right ventricular dysfunction. These also had a higher risk of all-cause hospitalizations and death. Based on a clustering analysis, 3 phenogroups of HCM according to the risk of AF occurrence can be identified. It can indicate which patients should be more monitored. 3 different AF-risk groups Intermediate risk group n = 524 High-risk group n= 207 Low-risk group n = 544 P Gender = Males (%) 338 (64.5) 103 (49.8) 422 (77.6) &amp;lt;0.001 Age (median [IQR]) 59.00 [47.00, 66.00] 63.00 [54.00, 74.00] 50.00 [38.00, 60.00] &amp;lt;0.001 Stroke (%) 29 (5.5) 44 (21.3) 5 (0.9) &amp;lt;0.001 Right ventricular failure (%) 10 (1.9) 41 (19.8) 0 (0.0) &amp;lt;0.001 None Mitral regurgitation (%) 207 (42.2) 25 (12.6) 416 (81.2) &amp;lt;0.001 Moderate to severe mitral regurgitation (%) 258 (52.6) 143 (72.3) 92 (18) &amp;lt;0.001 Mitral Valve elongation (%) 113 (23.5) 48 (24.9) 62 (12.1) Abnormal insertion of a papillary muscle (%) 13 (2.7) 12 (6.2) 6 (1.2) Mitral valve SAM (%) 214 (40.8) 115 (55.6) 77 (14.2) &amp;lt;0.001 Basal obstruction (%) 196 (37.4) 119 (57.5) 54 (9.9) &amp;lt;0.001 Anteroposterior LA diameter (mm) (median [IQR]) 44.00 [38.00, 49.00] 47.00 [42.00, 51.00] 39.00 [33.00, 43.00] &amp;lt;0.001 Mitral E/e’ Lateral (median [QR]) 10.00 [8.00, 13.53] 15.00 [10.11, 20.00] 7.50 [5.80, 10.00] &amp;lt;0.001 Mitral E/e’ Septal (median [QR]) 15.00 [11.18, 19.55] 18.40 [14.20, 23.50] 10.50 [8.33, 13.88] &amp;lt;0.001 Normal sPAP (%) 354 (82.1) 74 (39.6) 435 (98.0) &amp;lt;0.001 Event AF (%) 80 (15.3) 60 (29.0) 27 (5.0) &amp;lt;0.001 Any cause death (%) 29 (5.5) 36 (17.4) 7 (1.3) &amp;lt;0.001 Any cause hospitalization (%) 174 (33.2) 113 (54.6) 56 (10.3) &amp;lt;0.001 3 different groups on their caracteristics and AF-risk Abstract Figure.

P3746Temporal patterns of premature atrial contractions predict atrial fibrillation occurrence in bradycardia patients continuously monitored through pacemaker diagnostics

Abstract Background The frequency of premature atrial complexes (PACs) has been indirectly related with atrial fibrillation (AF) occurrence and adverse outcomes. Objective To evaluate whether temporal patterns of PACs are directly associated with AF onset in pacemaker patients with continuous monitoring of the atrial rhythm. Methods Overall, 193 pacemaker patients (49% female, 72±9 years old), enrolled in a national registry, were analyzed. Frequency of daily PACs was measured in a 14-day initial observation period, during which patients were in sinus rhythm. In the following period, temporal occurrence and frequency of daily PACs and eventual onset of AF were derived by pacemaker diagnostics. Results In the run-in period, median PACs frequency was 614 PACs/day (interquartile range=70–3056). Subsequently, in a median follow-up of 6 months, AF occurred in 109 patients, in particular in 37/96 (38.5%) patients with a PAC rate&lt;614 PACs/day and in 72/97 (74.2%) patients with PAC rate≥614 PACs/day (p&lt;0.001). In patients with AF occurrence, the number of daily PACs, normalized by dividing for the average of PACs in 10 preceding days, progressively increased in the 5–6 days preceding AF (Figure). Cox Model predictive analysis showed that the risk of AF was significantly higher in patients with a relative increase of the daily PACs higher than 30% compared with PACs average number in 10 preceding days (hazard ratio (95% confidence interval) = 3.67 (2.40–5.59), p&lt;0.001). PACs changes daily trend before AF Conclusion PACs frequency increases in the 5–6 days preceding AF onset. A relative increase of the daily PACs is significantly associated with the risk of AF occurrence.

Temporal patterns of premature atrial complexes predict atrial fibrillation occurrence in bradycardia patients continuously monitored through pacemaker diagnostics.

The frequency of premature atrial complexes (PACs) has been related with atrial fibrillation (AF) occurrence and adverse prognosis. Research objective was to evaluate whether temporal patterns of PACs are directly associated with AF onset in pacemaker patients with continuous monitoring of the atrial rhythm. Overall, 193 pacemaker patients (49% female, 72 ± 9years old), enrolled in a national registry, were analyzed. Frequency of daily PACs was measured in a 14-day initial observation period, during which patients were in sinus rhythm. In the following period, temporal occurrence and frequency of daily PACs and eventual onset of AF were derived by pacemaker diagnostics. In the run-in period, median PACs frequency was 614 PACs/day (interquartile range 70-3056). Subsequently, in a median follow-up of 6months, AF occurred in 109 patients, in particular in 37/96 (38.5%) patients with a PAC rate < 614 PACs/day and in 72/97 (74.2%) patients with PAC rate ≥ 614 PACs/day (p < 0.001). In patients with AF occurrence, the number of daily PACs, normalized by dividing for the average of PACs in ten preceding days, progressively increased in the 5days preceding AF. Cox model predictive analysis showed that the risk of AF was significantly higher in patients with a relative increase of the daily PACs higher than 30% compared with PACs average number in ten preceding days [hazard ratio (95% confidence interval) 3.67 (2.40-5.59), p < 0.001]. PACs frequency increases in the 5days preceding AF onset. A relative increase of the daily PACs is significantly associated with the risk of AF occurrence.

Effects of the short-term exposure to ambient air pollution on atrial fibrillation.

Atrial fibrillation (AF) is an important arrhythmia associated with cardiovascular morbidity and mortality. This study is focused on exploring the potential relationship between short-term air pollution exposure and occurrence of AF. A case-crossover design was used to investigate the effect of pollutants on AF occurrence among 100 patients from 2013 to 2014. The air pollutants included ambient particulate matter less than 2.5 μm in aerodynamic diameter (PM2.5 ), particulate matter less than 10 μm in aerodynamic diameter (PM10 ), nitrogen dioxide (NO2 ), sulfur dioxide (SO2 ), carbon monoxide (CO), and ozone (O3 ). Participants with cardiac implantable electronic devices implanted were followed-up to December 31, 2014. A 10 μg/m3 increase of PM2.5 and PM10 was associated with 3.8% (95% confidence interval [CI]: 1.4-6.2) and 2.7% (95% CI: 0.6-4.8) increase in the risk of AF occurrence, respectively. No statistically significant association was noted with SO2 , NO2 , CO, and O3 . Short-term exposure to particular matter, both PM2.5 and PM10 , is associated with an increased risk of AF. This further demonstrates the urgency for air quality monitoring and control in geographical area with intense pollution.

What Do We Currently Know About Metabolic Syndrome and Atrial Fibrillation?

Metabolic syndrome represents a cluster of atherogenic risk factors including hypertension, insulin resistance, obesity, and dyslipidemia. Considering that all of these risk factors could influence the development of atrial fibrillation, an association between atrial fibrillation and the metabolic syndrome has been suggested. Additionally, oxidative stress and inflammation have been involved in the pathogenesis of both metabolic syndrome and atrial fibrillation. The mechanisms that relate metabolic syndrome to the increased risk of atrial fibrillation occurrence are not completely understood. Metabolic syndrome and atrial fibrillation are associated with increased cardiovascular morbidity and mortality. Because atrial fibrillation is the most common arrhythmia, and along with the prevalence of metabolic syndrome constantly increasing, it would be very important to determine the relationship between these 2 entities, especially due to the fact that the risk factors of metabolic syndrome are mainly correctable. This review focused on the available evidence supporting the association between metabolic syndrome components and metabolic syndrome as a clinical entity with atrial fibrillation.

203: Correlation between P wave variables and apnea-hypopnea index in obstructive sleep apnea

Obstructive sleep apnea (OSA) is associated with several cardio-vascular abnormalities as atrial fibrillation (AF). AF occurrence in OSA increases the risk of stroke which worsens the prognosis of these patients. P wave dispersion (Pd) and maximal P wave duration (P max) are simple electrocardiographic parameters which reflect atrial conduction abnormalities and have been reported to be predictors of atrial fibrillation the aim of this study is to determine the correlation between apnea-hypopnea index (AHI) and P wave dispersion and maximal P wave duration. Forty patients (18 men and 22 women) who were diagnosed with OSA by overnight polysomnography were included in this prospective study. The mean age was 56±10 years old. They were all in sinus rhythm. Before initiating continuous positive airway pressure therapy, we evaluated on a 12 lead ECG P wave duration and P wave dispersion (P max - P min). Twenty four patients had severe OSA (AHI >30), 4 had moderate OSA (AHI between 15 and 30) and 12 had a mild OSA (AHI between 5 and 15). Mean P max duration was 119±21 ms. P wave dispersion was 93±6 ms. There was a significant positive correlation between P max and AHI (r= 0.45, p=0.001) and between P wave dispersion and AHI (r=0.42, p=0.001) The severity of OSA seems to be correlated with the importance of atrial conduction abnormalities. These results suggest the higher is the AHI the higher is the risk of AF occurrence in OSA. Further studies are needed to validate these results.

Assessment of left ventricular function by Doppler tissue imaging in patients with atrial fibrillation following acute myocardial infarction

Aims We studied tissue Doppler parameters in patients with atrial fibrillation following acute myocardial infarction, and their relation to P wave durations and P dispersion. Methods Echocardiographic examination was performed in 84 consecutive patients with first anterior acute myocardial infarction. In addition to other conventional echocardiographic parameters, the peak systolic (Sm), early diastolic (Em) and late diastolic (Am) velocities were obtained at the lateral corner of the mitral annulus by pulsed wave tissue Doppler. The Em/Am ratio and the ratio of early diastolic mitral inflow velocity to Em ( E/Em), which is a marker of diastolic filling pressure, were calculated. Electrocardiogram was recorded from all patients on admission; P wave measurements were also performed. Results Atrial fibrillation occurred in 20 (23.8%) of 84 patients. The patients with atrial fibrillation had significant reduction of Em (5.6±1.5 vs. 8.7±2.7 cm/s, p<0.001), Em/Am (0.61±0.27 vs. 0.84±0.23, p=0.001) and Sm (7.1±1.0 vs. 8.3±1.9 cm/s, p<0.001) values compared with those without. The E/Em ratio (14.45±4.62 vs. 7.47±2.79, p<0.001), P maximum (102±11 vs. 95±11 ms, p=0.02) and P dispersion (35±7 vs. 26±7 ms, p<0.001) were significantly higher in patients with atrial fibrillation than in those without. In all patients, P dispersion showed significant correlation with Em ( r=−0.33, p=0.002), Sm ( r=−0.40, p<0.001) and E/Em ( r=0.32, p=0.003). When E/Em≥10 was used as cutpoint, atrial fibrillation could be predicted with a sensitivity of 90%, and a specificity of 84%. Conclusions The patients with atrial fibrillation following acute myocardial infarction have reduced systolic and diastolic mitral annular velocities and increased E/Em ratio, P maximum and P dispersion values compared to those without. P dispersion is correlated with systolic and diastolic left ventricular function after acute myocardial infarction. The E/Em ratio appears to be a useful parameter for assessing the risk of atrial fibrillation occurrence after anterior acute myocardial infarction.