Effect of race on the frequency of postoperative atrial fibrillation following coronary artery bypass grafting

Atrial fibrillation (AF) commonly complicates the postoperative course after coronary artery bypass grafting (CABG). Among the general population, African Americans have been shown to have a lower prevalence of AF than European Americans. Although many factors have been identified to predict risk for postoperative AF, race has not been examined. All patients aged ≥18 years who underwent CABG at Henry Ford Hospital during a 5-year period from January 1, 2004, to December 31, 2008, were included. Patients were excluded for any previous diagnosis of AF or if they had concomitant valve surgery at the time of CABG. The incidence of AF was determined by International Classification of Diseases, Ninth Revision, coding from postoperative hospitalization records. Overall, 1,001 patients were eligible for analysis. Of these, 731 (73%) were European American and 270 (27%) were African American. The African American group had a higher prevalence of hypertension (75.6% vs 58.8%, p <0.001) and heart failure (22.6% vs 15.7%, p = 0.01) and a trend toward a higher prevalence of diabetes mellitus (38.1% vs 33.4%, p = 0.159). Postoperative AF was diagnosed in 214 European Americans (29.3%) and 50 African Americans (18.5%) (p = 0.001). In multivariate analysis adjusting for age strata, gender, hypertension, diabetes, and heart failure, African Americans had less postoperative AF than European Americans, with an adjusted odds ratio of 0.539 (95% confidence interval 0.374 to 0.777, p = 0.001). In conclusion, African Americans have a significantly reduced incidence of AF compared to European Americans after CABG.     

Detailed characterization of epidemiology of uninvestigated dyspepsia and its impact on quality of life among African Americans as compared to Caucasians

BACKGROUND AND AIMS: We wished to study the prevalence as well as the sociodemographic characteristics and quality of life (QoL) of African American patients with uninvestigated dyspepsia (UD) among the population at large and compare it to the Caucasians. METHODS: A total of 990 adults from nine different sites in the Jackson, Mississippi metropolitan area (670 African Americans and 320 Caucasians), completed self-administered questionnaires providing sociodemographic information, and details regarding bowel habits and associated symptoms for diagnosing the presence or absence of UD based on ROME II criteria. QoL was assessed by the SF-12 questionnaire. RESULTS: Of the 990 participants 247 had UD, giving a total sample prevalence of 24.9% (African Americans = 24.3%, Caucasians = 26.2%). Adjusting for other risk factors in a reduced logistic regression model, we found female sex (OR 1.8; CI 1.2-2.6; p < 0.01), lower education (p < 0.01), and larger size of household (p = 0.01) to be important correlates of UD prevalence whereas the lower household income showed a trend toward statistical significance (p = 0.057). Using the adjusted odds ratio as an estimate of relative risk, Caucasians were 1.5 (95% CI = 11.1-2.1; p = 0.017) more likely than African Americans to have UD. In terms of an index for QoL on SF-12 (possible score = 1-44, with 44 being ideal), the adjusted mean score was significantly lower for adults with UD compared to non-UD adults (30.4 vs 35.0; p < 0.01). However, there was no difference in impairment of life in Caucasians versus African Americans (32.9 vs 32.5; p = 0.36). CONCLUSIONS: UD occurs less frequently among African Americans. While UD affects QoL among both Caucasians and African Americans, the degree of impairment is similar.     

Racial Differences in Atrial Fibrillation Prevalence and Left Atrial Size

Background

Previous studies relying on clinical care data have suggested that atrial fibrillation is less common in African Americans than Caucasians, but the mechanism remains unknown. Clinical care may itself vary by race, potentially affecting the accuracy of atrial fibrillation ascertainment in studies relying on clinical data. We sought to examine racial differences in atrial fibrillation prevalence determined by protocol-driven electrocardiograms (ECGs) obtained in prospective cohort studies and to study racial differences in echocardiographic characteristics.

Methods

We pooled primary data from 3 cohort studies with atrial fibrillation adjudicated from study protocol ECGs and documentation of potentially important confounders: the Heart and Soul Study (n = 1014), the Heart and Estrogen-Progestin Replacement Study (n = 2673), and The Osteoporotic Fractures in Men Sleep Study (n = 2911). Left atrial anatomic dimensions were compared among races from sinus rhythm echocardiograms in the Heart and Soul Study.

Results

Of the 6611 participants, 268 (4%) had atrial fibrillation: Caucasians had the highest prevalence (5%), and African Americans had the lowest (1%; P <.001 for each compared with all other races). After adjustment for potential confounders, Caucasians had a 3.8-fold greater odds of having atrial fibrillation than African Americans (95% confidence interval, 1.6-8.8, P = .002). Although ventricular and atrial volumes and function were similar in Caucasians and African Americans, Caucasians had a 2 mm larger anterior-posterior left atrial diameter after adjusting for potential confounders (95% confidence interval, 1-3 mm, P <.001).

Conclusion

ECG confirmed atrial fibrillation is more common in Caucasians than in African Americans, which might be related to the larger left atrial diameter observed in Caucasians.     

Comparison of frequency of atrial fibrillation after coronary artery bypass grafting in African Americans versus European Americans

In the general population, African Americans experience atrial fibrillation (AF) less frequently than European Americans. This difference could also exist in the incidence of this arrhythmia after cardiac surgery, but this possibility has been insufficiently examined. To test the association of such an ethnic difference, we compared the incidence of postoperative AF in a consecutive series of 2,312 African Americans and 6,054 European Americans who underwent isolated coronary artery bypass grafting from July 2000 to June 2007. Raw differences between the cohorts in the incidence of new AF were adjusted to take into account the baseline differences. Postoperatively, new-onset AF developed in 504 (22%) of 2,312 African-American patients and in 1,838 (30%) of 6,054 European-American patients (p <0.01). After adjustment with logistic regression analysis for numerous baseline differences, African Americans remained less likely to develop AF (odds ratio 0.63, 95% confidence interval 0.55 to 0.72; p <0.001). Risk was also adjusted using propensity matching. In that analysis, 457 (22%) of 2,059 African-American patients had postoperative AF, as did 597 (29%) of 2,059 matched European-American patients (p <0.01). In conclusion, AF was significantly less common among African-American patients than among European-American patients after coronary artery bypass grafting.     

Racial Disparities in the Utilization and Outcomes of Transcatheter Mitral Valve Repair: Insights From a National Database

BackgroundThere is paucity of data on racial disparities in the utilization and outcomes of transcatheter mitral valve repair (TMVR).MethodsWe queried the National inpatient Sample database (2012–2016) for TMVR hospitalizations among Caucasian and African American patients. We conducted a propensity score matching analysis to compare outcomes of Caucasians versus African Americans. The main study outcome was in-hospital mortality.ResultsAmong 7940 TMVR procedures performed, 680 (8.6%) were performed in African Americans. TMVR was increasingly performed for both Caucasians and African Americans (P_trend = 0.01), although the proportion of African Americans did not change significantly over time (P_trend = 0.45). Compared to African Americans, Caucasians undergoing TMVR were significantly older (77.7 ± 10.8 vs. 67.2 ± 14.28, p < .001) and less likely to be women (45.3% vs.60.3%, p < .001). Caucasians undergoing TMVR had a higher in-hospital mortality compared with African Americans before matching (2.5% vs. 1.5%, odds ratio [OR] 1.75; 95% confidence interval [CI] 1.17:2.63, p = .01) as well as after matching (4.7% vs. 1.6%, OR 3.10; 95% CI 1.61:5.97, p < .001). Caucasians had higher in-hospital cardiac arrest and pacemaker insertion and shorter median length of stay. There was no difference in the incidence of other in-hospital outcomes between Caucasians and African Americans.ConclusionThis nationwide observational analysis showed a steady increase in number of TMVRs among Caucasians and African Americans. TMVR was performed in a select cohort of African Americans who were significantly younger and more likely to be women compared with Caucasians. Caucasians undergoing TMVR had higher in-hospital mortality compared with African Americans. Further research is needed to explore the reasons behind the racial disparities in the utilization and outcomes of TMVR.     

Incident frailty and cognitive impairment by heart failure status in older patients with atrial fibrillation: the SAGE-AF study

BackgroundAtrial fibrillation (AF) and heart failure (HF) frequently co-occur in older individuals. Among patients with AF, HF increases risks for stroke and death, but the associations between HF and incident cognition and physical impairment remain unknown. We aimed to examine the cross-sectional and prospective associations between HF, cognition, and frailty among older patients with AF.MethodsThe SAGE-AF (Systematic Assessment of Geriatric Elements in AF) study enrolled 1244 patients with AF (mean age 76 years, 48% women) from five practices in Massachusetts and Georgia. HF at baseline was identified from electronic health records using ICD-9/10 codes. At baseline and 1-year, frailty was assessed by Cardiovascular Health Survey score and cognition was assessed by the Montreal Cognitive Assessment.ResultsPatients with prevalent HF (n = 463, 37.2%) were older, less likely to be non-Hispanic white, had less education, and had greater cardiovascular comorbidity burden and higher CHA₂DS₂VASC and HAS-BLED scores than patients without HF (all P''s < 0.01). In multivariable adjusted regression models, HF (present vs. absent) was associated with both prevalent frailty (adjusted odds ratio [aOR]: 2.38, 95% confidence interval [CI]: 1.64-3.46) and incident frailty at 1 year (aOR: 2.48, 95% CI: 1.37-4.51). HF was also independently associated with baseline cognitive impairment (aOR: 1.60, 95% CI: 1.22-2.11), but not with developing cognitive impairment at 1 year (aOR 1.04, 95%CI: 0.64-1.70).ConclusionsAmong ambulatory older patients with AF, the co-existence of HF identifies individuals with physical and cognitive impairments who are at higher short-term risk for becoming frail. Preventive strategies to this vulnerable subgroup merit consideration.     

Rate vs rhythm control in patients with atrial fibrillation and heart failure: a systematic review and meta-analysis of randomised controlled trials

Background

Atrial fibrillation (AF) is a common arrhythmia that can promote or worsen heart failure (HF). Our purpose was to compare the effects of rate and rhythm control in patients with atrial fibrillation and heart failure.

Methods

We developed a systematic search in August 2010 through CENTRAL and MEDLINE databases to identify randomised controlled trials (RCTs) comparing rate control with rhythm control in patients with both AF and HF.We analysed mortality, hospitalisations, stroke/thromboembolic events, quality of life, and drugs adverse events. Relative risks (RR) and 95% confidence intervals (95% CI) were calculated for mortality and hospitalisations. The remaining outcomes were analysed qualitatively.

Results

Four RCTs with a total of 2486 patients with atrial fibrillation and heart failure were identified. Mortality and stroke/thromboembolic events were not significantly different in rate and rhythm control arms [RR 1.03; 95% CI: 0.90–1.17] and [RR 1.09; 95% CI: 0.61–1.96], respectively. Hospitalisations were less frequent with rate control than with rhythm control [RR 0.92; 95% CI: 0.86–0.98; p = 0.008], in 3 studies involving 2425 patients. Number needed to treat to prevent one hospitalisation was 19 patients.

Conclusions

In patients with AF and HF, rate control compared with rhythm control showed inferior risk of hospitalisation.     

Operative and late coronary artery bypass grafting outcomes in matched African-American versus Caucasian patients: evidence of a late survival-Medicaid association.

OBJECTIVES: This study sought to determine whether African-American versus Caucasian race is a determinant of early or late coronary artery bypass surgery (CABG) outcomes. BACKGROUND: African Americans are referred to CABG less frequently than Caucasians and Medicaid coverage is disproportionately common among those who are referred. How these factors affect the relative early and late CABG outcomes in these groups is incompletely elucidated. METHODS: A retrospective cohort comparison of operative and 12-year outcomes for 304 African-American and 6,073 Caucasian consecutive patients who underwent isolated CABG (1991 to 2003) at an urban community hospital was used. Results were further confirmed in propensity-matched subgroups (n = 301 each). RESULTS: African Americans were younger (62 vs. 64 years, median), more were female (46% vs. 30%), more were on Medicaid (29% vs. 6.3%) and had more comorbidities. These differences were eliminated after matching. A total of 161 operative and 1,080 late deaths have been documented. Operative mortality was similar (African American versus Caucasian: 3.0% vs. 2.5%; p = 0.81). Unadjusted Kaplan-Meier survival at 1, 5, and 10 years (93.4%, 80.3%, and 66.1% vs. 94.8%, 86.5%, and 71.7%) was worse in African Americans (hazard ratio [HR] = 1.38; p = 0.004), but similar for matched groups (HR = 1.03; p = 0.97). After risk adjustment, race did not predict operative (odds ratio = 1.17; p = 0.69) or late (HR = 1.15; p = 0.28) mortality. However, Medicaid status (HR = 1.54; p < 0.005) predicted worse survival, which was verified in a case-matched Medicaid (n = 469) versus non-Medicaid analysis. The latter showed that in younger Medicaid patients without companion Medicare coverage, late mortality was nearly doubled (HR = 1.96; p = 0.003) with systematically increasing death hazard after the second year. CONCLUSIONS: African-American race per se is not associated with worse operative or late outcomes underscoring that CABG should be based on clinical characteristics only. Alternatively, Medicaid status, which is more prevalent among African Americans, is associated with worse late survival, especially in non-Medicare patients. Studies are needed to elucidate this late Medicaid-CABG outcome association.     

A new pacemaker algorithm for the treatment of atrial fibrillation: results of the Atrial Dynamic Overdrive Pacing Trial (ADOPT)

OBJECTIVES: The Atrial Dynamic Overdrive Pacing Trial (ADOPT) was a single blind, randomized, controlled study to evaluate the efficacy and safety of the atrial fibrillation (AF) Suppression Algorithm (St. Jude Medical Cardiac Rhythm Management Division, Sylmar, California) in patients with sick sinus syndrome and AF. BACKGROUND: This algorithm increases the pacing rate when the native rhythm emerges and periodically reduces the rate to search for intrinsic atrial activity. METHODS: Symptomatic AF burden (percentage of days during which symptomatic AF occurred) was the primary end point. Patients underwent pacemaker implantation, were randomized to DDDR with the algorithm on (treatment) or off (control), and were followed for six months. RESULTS: Baseline characteristics and antiarrhythmic drugs used were similar in both groups. The percentage of atrial pacing was higher in the treatment group (92.9% vs. 67.9%, p < 0.0001). The AF Suppression Algorithm reduced symptomatic AF burden by 25% (2.50% control vs. 1.87% treatment). Atrial fibrillation burden decreased progressively in both groups but was lower in the treatment group at each follow-up visit (one, three, and six months) (p = 0.005). Quality of life scores improved in both groups. The mean number of AF episodes (4.3 +/- 11.5 control vs. 3.2 +/- 8.6 treatment); total hospitalizations (17 control vs. 15 treatment); and incidence of complications, adverse events, and deaths were not statistically different between groups. CONCLUSIONS: The ADOPT demonstrated that overdrive atrial pacing with the AF Suppression Algorithm decreased symptomatic AF burden significantly in patients with sick sinus syndrome and AF. The decrease in relative AF burden was substantial (25%), although the absolute difference was small (2.50% control vs. 1.87% treatment).     

The association of race and ethnicity with disease expression in male US veterans with rheumatoid arthritis

OBJECTIVE: To examine the association of race/ethnicity with measures of disease activity and severity among male US veterans with rheumatoid arthritis (RA). METHODS: Measures of disease activity and severity were examined in a group of US veterans (n = 573) with RA, comparing measures in African American men (n = 79) with Caucasian men (n = 494). Dichotomous variables were compared using logistic regression while continuous variables were examined using linear regression, adjusting for the effects of age, disease duration, and smoking status. RESULTS: Compared to Caucasians, African Americans were slightly younger (65.0 vs 67.1 yrs; p = 0.09) at enrollment and had a similar age at disease onset (50.5 vs 50.6 years; p = 0.98). After adjusting for age, disease duration, and smoking status, there were no differences based on race/ethnicity in rheumatoid factor positivity, the presence of radiographic changes, physical functioning, swollen joint counts, Disease Activity Score (DAS28), or global well-being scores. In contrast, African Americans were about 50% less likely than Caucasians with RA to have subcutaneous nodules (adjusted OR 0.51, 95% CI 0.30-0.86) and had lower tender joint counts (p = 0.007), associations that were attenuated and not significant with further adjustment for collection site. CONCLUSION: With the possible exception of lower rates of rheumatoid nodules and lower tender joint counts in African Americans, there is little evidence to support the existence of important racial/ethnic differences in RA disease expression between African American and Caucasian men.     

The Relationship Between Atrial Fibrillation,Mitral Regurgitation,and Heart Failure Subtype: The ARIC Study

BackgroundAtrial fibrillation (AF) and mitral regurgitation (MR) are closely interrelated in the setting of heart failure (HF). Here we investigate the prevalence and prognostic significance of AF in patients with acute decompensated HF (ADHF) stratified by MR severity.Methods and ResultsThe Atherosclerosis Risk in Communities Study investigated ADHF hospitalizations in residents greater than or equal to 55 years of age in 4 US communities. ADHF cases were stratified by MR severity (none/mild or moderate/severe) and HF subtype (HF with reduced [HFrEF] or preserved [HFpEF] ejection fraction). The odds of AF in patients with increasing MR severity was estimated using multivariable logistic regression, adjusting for age, race, sex, diabetes, hypertension, coronary artery disease, hemodialysis, stroke, and anemia. Cox regression models were used to assess the association of AF with 1-year mortality in patients with HFpEF and HFrEF, stratified by MR severity and adjusted as described, also adjusting for the year of hospitalization. From 2005 to 2014, there were 3,878 ADHF hospitalizations (17,931 weighted). AF was more likely in those with higher MR severity regardless of HF subtype; more so in HFpEF (odds ratio [OR] 1.38, 95% confidence interval [CI], 1.31–1.45) than in HFrEF (OR, 1.19, 95% CI, 1.13–1.25) (interaction P [by HF subtype] < .01). When stratified by HF type, association between AF and 1-year mortality was noted in patients with HFpEF (OR, 1.28, 95% CI 1.04–1.56) but not HFrEF (OR 0.96, 95% CI 0.79–1.16) (interaction by EF subtype, P = .02).ConclusionsIn patients with ADHF, AF prevalence increased with MR severity and this effect was more pronounced in HFpEF compared with HFrEF. AF was associated with an increased 1-year mortality only in patients with HFpEF and concomitant moderate/severe MR.RegistrationNCT00005131, https://clinicaltrials.gov/ct2/show/NCT00005131     

Clinical prediction rule for atrial fibrillation after coronary artery bypass grafting

OBJECTIVES: This study was designed to devise and validate a practical prediction rule for atrial fibrillation/atrial flutter (AF) after coronary artery bypass grafting (CABG) using easily available clinical and standard electrocardiographic (ECG) criteria. BACKGROUND: Reported prediction rules for postoperative AF have suffered from inconsistent results and controversy surrounding the added predictive value of a prolonged P-wave duration. METHODS: In 1,851 consecutive patients undergoing CABG with cardiopulmonary bypass, preoperative clinical characteristics and standard 12-lead ECG data were examined. Patients were continuously monitored for the occurrence of sustained postoperative AF while hospitalized. Multiple logistic regression was used to determine significant predictors of AF and to develop a prediction rule that was evaluated through jackknifing. RESULTS: Atrial fibrillation occurred in 508 of 1,553 patients (33%). Multivariate analysis showed that greater age (odds ratio [OR] 1.1 per year [95% confidence intervals (CI) 1.0 to 1.1], p < 0.0001), prior history of AF (OR 3.7 [95% CI 2.3 to 6.0], p < 0.0001), P-wave duration >110 ms (OR 1.3 [95% CI 1.1 to 1.7], p = 0.02), and postoperative low cardiac output (OR 3.0 [95% CI 1.7 to 5.2], p = 0.0001) were independently associated with AF risk. Using the prediction rule we defined three risk categories for AF: <60 points, 61 of 446 (14%); 60 to 79 points, 330 of 908 (36%); and >or=80 points, 117 of 199 (59%). The area under the receiver-operator characteristic curve for the model was 0.69. CONCLUSIONS: These data show that post-CABG AF can be predicted with moderate accuracy using easily available patient characteristics and may prove useful in prognostic and risk stratification of patients after CABG. The presence of intraatrial conduction delay on ECG contributed least to the prediction model.     

Frequency of recurrent atrial fibrillation after catheter ablation of overt accessory pathways.

The effect of successful catheter ablation of overt accessory pathways on the incidence of atrial fibrillation (AF) was studied in 129 symptomatic patients with (n = 75) or without (n = 54) previous documented AF. Fourteen had had ventricular fibrillation. Factors predictive of recurrence were examined, including electrophysiologic parameters. Atrial vulnerability was defined as induction of sustained AF (greater than 1 minute) using single, then double, atrial extrastimuli at 2 basic pacing cycle lengths. When compared to patients with only reciprocating tachycardia, patients with clinical AF included more men (77 vs 54%, p = 0.008) and were older (35 +/- 12 vs 29 +/- 12 years, p = 0.01). They had a significantly shorter cycle length leading to anterograde accessory pathway block (252 +/- 42 vs 298 +/- 83 ms, p less than 0.001), greater incidences of atrial vulnerability (89 vs 24%, p less than 0.001) and subsequent need for cardioversion (51 vs 15%, p less than 0.001). After discharge, the follow-up period was 35 +/- 12 months (range 18 to 76); 7 patients with previous spontaneous AF (9%) had recurrence at a mean of 10 months after ablation. Age, presence of structural heart disease accessory pathway location, atrial refractory periods and accessory pathway anterograde conduction parameters were not predictive of AF recurrence. Persistence of atrial vulnerability after ablation was the only factor associated with further recurrence of AF. Atrial vulnerability was observed after ablation in only 56% of patients with previous AF versus 89% before ablation. It is concluded that successful catheter ablation of accessory pathways prevents further recurrence of AF in 91% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Postoperative atrial fibrillation and mortality after coronary artery bypass surgery

OBJECTIVES: We sought to determine if the occurrence of postoperative atrial fibrillation (AF) affects early or late mortality following coronary artery bypass surgery (CABG). BACKGROUND: Atrial fibrillation is the most common arrhythmia seen following CABG. METHODS: The Texas Heart Institute Cardiovascular Research Database was used to identify all patients that developed AF after isolated initial CABG from January 1993 to December 1999 (n = 994). This population was compared with patients who underwent CABG during the same period but did not develop AF (n = 5,481). In-hospital end points were adjusted using logistic regression models to account for baseline differences. Long-term survival was evaluated using a retrospective cohort design, where Cox proportional hazards methods were used to adjust for baseline differences, and with case-matched populations (n = 390, 195 per arm). RESULTS: Atrial fibrillation was diagnosed in 16% of the population. Postoperative AF was associated with greater in-hospital mortality (odds ratio [OR] 1.7, p = 0.0001), more strokes (OR 2.02, p = 0.001), prolonged hospital stays (14 vs. 10 days, p < 0.0001), and a reduced incidence of myocardial infarction (OR 0.62, p = 0.01). At four to five years, survival was worse in patients who developed postoperative AF (74% vs. 87%, p < 0.0001 in the retrospective cohort; 80% vs. 93%, p = 0.003 in the case-matched population). On multivariate analysis, postoperative AF was an independent predictor of long-term mortality (adjusted OR 1.5, p < 0.001 in the retrospective cohort; OR 3.4, p = 0.0018 in the case-matched population). CONCLUSIONS: The occurrence of AF following CABG identifies a subset of patients who have a reduced survival probability following CABG. The impact of various strategies, such as antiarrhythmics and warfarin, aimed at reducing AF and its complications deserves further study.     

Association of atrial nicotinamide adenine dinucleotide phosphate oxidase activity with the development of atrial fibrillation after cardiac surgery.

OBJECTIVES: Our goal was to evaluate the role of myocardial nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and plasma markers of oxidative stress in the pathogenesis of post-operative atrial fibrillation (AF). BACKGROUND: Atrial fibrillation is a common complication of cardiac surgery, leading to increased morbidity and prolonged hospitalization. Experimental evidence suggests that oxidative stress may be involved in the pathogenesis of AF; however, the relevance of this putative mechanism in patients undergoing cardiac surgery is unclear. METHODS: We measured basal and NADPH-stimulated superoxide production in right atrial appendage samples from 170 consecutive patients undergoing conventional coronary artery bypass surgery. Plasma markers of lipid and protein oxidation (thiorbabituric acid-reactive substances, 8-isoprostane, and protein carbonyls) were also measured in blood samples drawn from a central line before surgery and after reperfusion. RESULTS: Patients who developed AF after surgery (42%) were older and had a significantly increased atrial NADPH oxidase activity than patients who remained in sinus rhythm (SR) (in relative light units/s/mug protein: 4.78 +/- 1.44 vs. 3.53 +/- 1.04 in SR patients, p < 0.0001). Plasma markers of lipid and protein oxidation increased significantly after reperfusion; however, neither pre-operative nor post-operative measurements differed between patients who developed AF and those who remained in SR after surgery. Multivariate analysis identified atrial NADPH oxidase activity as the strongest independent predictor of post-operative AF (odds ratio 2.41; 95% confidence interval 1.71 to 3.40, p < 0.0001). CONCLUSIONS: Atrial NADPH oxidase activity is independently associated with an increased risk of post-operative AF, suggesting that this oxidase system may be a key mediator of atrial oxidative stress leading to the development of AF after cardiac surgery.     

Atrial Remodeling in an Ovine Model of Anthracycline‐Induced Nonischemic Cardiomyopathy: Remodeling of the Same Sort

Atrial Remodeling in Doxorubicin Cardiomyopathy. Introduction: All preclinical studies of atrial remodeling in heart failure (HF) have been confined to a single model of rapid ventricular pacing. To evaluate whether the atrial changes were specific to the model or represented an end result of HF, this study aimed to characterize atrial remodeling in an ovine model of doxorubicin‐induced cardiomyopathy. Methods and Results: Fourteen sheep, 7 with cardiomyopathy induced by repeated intracoronary doxorubicin infusions and 7 controls, were studied. The development of HF was monitored by cardiac imaging and hemodynamic parameters. Open chest electrophysiological study was performed using custom‐made 128‐electrode epicardial plaque assessing effective refractory period (ERP) and conduction velocity. Atrial tissues were harvested for structural analysis. The HF group had demonstrable moderate global HF (left ventricular ejection fraction [LVEF]: 37.1 vs 46.4%; P = 0.003) and showed the following compared to controls: left atrial dilatation (P = 0.02) and dysfunction (P = 0.005); longer P‐wave duration (P < 0.05); higher ERP at all cycle lengths (P ≤ 0.002) and locations (P < 0.001); slower conduction velocity (P < 0.001); increased conduction heterogeneity index (P < 0.001); increased atrial fibrosis (right atrial [RA]: 5.9 ± 2.6 vs 2.8 ± 0.9%; P < 0.0001, left atrial [LA]: 3.7 ± 2.2 vs 2.4 ± 1.1%; P = 0.002), and longer induced atrial fibrillation (AF) episodes (16 ± 22 vs 2 ± 3 seconds; P = 0.04). Conclusion: In this model of HF, there was significant atrial remodeling characterized by atrial enlargement/dysfunction, increased fibrosis, slowed/heterogeneous conduction, and increased refractoriness associated with more sustained AF. These findings appear the “same sort” to previous models of HF implicating a final common substrate leading to the development of AF in HF. (J Cardiovasc Electrophysiol, Vol. 22, pp. 175‐182, February 2011)     

Effectiveness of Bi-atrial Pacing for Reducing Atrial Fibrillation after Coronary Artery Bypass Graft Surgery

Atrial fibrillation (AF) is common after cardiac surgery and adds significant cost and morbidity. The use of prophylactic pacing strategies to prevent post-operative AF has been controversial. We previously performed a pilot study which suggested that the combination of beta-blockers and bi-atrial pacing (BAP) may reduce AF after cardiac surgery.We prospectively randomized 118 patients to continuous BAP for up to 96 hours post-operatively versus standard therapy. All patients were treated with beta-blockers as tolerated. Patients were paced in the AAI mode at a rate of 100 pulses per minute. The primary endpoint of the study was the occurrence of sustained AF (>10 minutes).There was a significant reduction in the incidence of AF in the BAP group among patients undergoing coronary artery bypass graft surgery with or without aortic valve replacement (35% vs. 19% AF; OR=0.38, 95% CI 0.15, 0.93; p <0.05). Including patients undergoing isolated aortic valve surgery (n=7), there remained a strong trend toward a reduction of AF with pacing (no atrial pacing [NAP] vs. BAP; 35% vs. 21% AF; OR=0.48, 95% CI 0.21, 1.11; p=0.08). Patients age 70 or greater benefited most from pacing (NAP vs. BAP; 55 vs. 25% AF; p<0.05), while those less than 70 years of age did not (17 vs. 18% p=NS). There was a significant reduction in the amount of time spent in the intensive care unit among patients receiving BAP (50±40 vs. 37±25[emsp4 ]h; p<0.05).BAP together with beta-blockade after coronary artery bypass graft surgery reduces the incidence of post-operative atrial AF. Elderly patients (age 70 or greater) appear to benefit most, and may be a group to whom this therapy should be targeted.     

Impact of atrial fibrillation on the no-flow phenomenon during primary percutaneous coronary intervention

Background Atrial fibrillation(AF)is reported to be associated with worse flow in patients with the treatment of coronary thrombolysis. However,few studies investigated the impact of atrial fibrillation on the noreflow phenomenon in ST-segment elevation myocardial infarction(STEIMI)patients undergoing primary percutaneous intervention(PCI). Methods 1163 STEMI patients undergoing primary PCI from Jan 2013 to Dec2019 were enrolled. Atrial fibrillation was diagnosed based on the electrocardiogram's findings. Patients with a TIMI flow rate less than 3 were considered to have no-reflow. Factors related to the no-reflow phenomenon was analyzed by the logistic regression analysis. Results 158 patients were in the AF group and 1005 patients were in the non-AF group. The AF group had a significantly higher occurrence of cardiogenic shock(11.4% vs. 5.6%,P0.001),and in-hospital mortality(9.5% vs. 3.1%,P0.001)than the non-AF group. The multivariate analysis showed that AF was an independent risk factor for the no-reflow phenomenon after primary PCI(OR:2.11,95% CI:1.27-3.88,P=0.014). Conclusions STEMI patients with AF would have higher in-hospital adverse events and no-reflow phenomenon than though without AF.[S Chin J Cardiol 2020;21(2):98-103]     

Reduced incidence of vagally induced atrial fibrillation and expression levels of connexins by n-3 polyunsaturated fatty acids in dogs.

OBJECTIVES: This open-label canine study assessed whether n-3 polyunsaturated fatty acids (PUFAs) prevent vagally induced atrial fibrillation (AF) and influence atrial tissue expression levels of connexins (CXs). BACKGROUND: n-3 polyunsaturated fatty acids in fish oils protect against sudden cardiac death and reduce postoperative AF. Changes in spatial organization of gap junctions or cellular CX levels have been linked to arrhythmogenesis. METHODS: Vagally induced AF was studied. Eight dogs were given fish oil daily for 14 days. Eight control dogs had reproducibly induced AF and were re-evaluated after intravenous administration of fish oil. Atrial fibrillation was compared, and n-3 PUFA, CX40, and CX43 protein levels were assessed in atrial biopsies. RESULTS: Atrial tissue n-3 PUFA levels increased in oral treatment dogs (5.78 +/- 0.71% vs. 2.49 +/- 0.46% in control animals, p < 0.001). No difference was observed for atrial refractory periods or hemodynamic or electrocardiographic parameters. Incidence of AF in oral treatment dogs decreased 79% with the extra stimulus technique (10.5% vs. 48.9%, p = 0.003) and 42% with burst induction (22.5% vs. 38.8%, p = 0.038). Both CX40 and CX43 levels were lower in oral treatment dogs (60% [p = 0.019] and 42% [p = 0.038] lower, respectively); protection against AF was mostly related to reduced CX40 expression levels (p = 0.02). In dogs that were given intravenous n-3 PUFAs, AF inducibility by the extra stimulus technique was reduced from 75.0% to 28.6% (p = 0.002). CONCLUSIONS: Oral treatment with fish oils increased atrial n-3 PUFA levels and reduced vulnerability to induction of AF in this dog model. Modulation of cardiac CX by n-3 PUFAs probably contributes to the antiarrhythmic effects of fish oils.