Mitochondrial biological function and risk of atrial fibrillation and atrial flutter: A 2-sample Mendelian randomization study.

Current research suggests that mitochondrial dysfunction can be a contributing factor in the development of cardiac arrhythmias. In pursuit of elucidating the causal link between the biological functions of mitochondria and the occurrence of atrial fibrillation/flutter, we conducted a 2-sample Mendelian randomization (MR) study. Mitochondrial proteins were selected for exposure in this study. To enhance the accuracy of our study, we selected data on AF/AFL from the FinnGen study and the UK Biobank for MR analysis, respectively. The inverse variance-weighted method was utilized as the primary analysis technique for MR. In addition, we performed a series of sensitivity analyses to detect heterogeneity and horizontal pleiotropy. MR results indicated a significant positive association between NAD-dependent protein deacylase sirtuin-5 and AF/AFL (odds ratio = 1.084, 95% confidence interval: 1.037-1.133, P = 3.679 × 10-4, Adjusted P = .024), with consistent outcomes observed in replication analysis (odds ratio = 1.002, 95% confidence interval: 1.001-1.003, P = 4.808 × 10-4, Adjusted P = .032). NAD-dependent protein deacylase sirtuin-5 can significantly promote the occurrence of AF/AFL, and its specific mechanisms warrant further investigation.

The burden of atrial fibrillation/flutter in the Middle East and North Africa region and its associated risk factors from 1990 to 2019.

BACKGROUND: Atrial fibrillation and flutter (AFF) are the most common cardiac arrhythmias globally, contributing to substantial morbidity and mortality. The Middle East and North Africa (MENA) region face unique challenges in managing cardiovascular diseases, including AFF, due to diverse sociodemographic factors and healthcare infrastructure variability. This study aims to comprehensively evaluate the burden of AFF in MENA from 1990 to 2019. METHODS: Data were obtained from the Global Burden of Diseases Study 2019, a comprehensive source incorporating diverse data inputs. The study collected global, regional, and national Age-Standardized Incidence Rate (ASIR), Age-Standardized Mortality Rate (ASMR), and Age-Standardized Disability-Adjusted Rate (ASDR), Mortality across sex, age groups, and years. LOESS regression was employed to determine the relationship between age-standardized rates attributed to AFF and Socio-Demographic Index (SDI). RESULTS: The study found minimal change in ASIR of AFF in MENA from 1990 to 2019, with a slight increase observed in ASMR and ASDR during the same period. Notably, AFF burden was consistently higher in females compared to males, with age showing a direct positive relationship with AFF burden. Iraq, Iran, and Turkey exhibited the highest ASIR, while Qatar, Bahrain, and Oman had the highest ASMR and ASDR in 2019. Conversely, Kuwait, Libya, and Turkey displayed the lowest ASMR and ASDR rates. CONCLUSION: This study underscores the persistent burden of AFF in MENA and identifies significant disparities across countries. High systolic blood pressure emerged as a prominent risk factor for mortality in AFF patients. Findings provide crucial insights for policy-making efforts, resource allocation, and intervention strategies aimed at reducing the burden of cardiovascular diseases in the MENA region.

Ten-Year Trend of Oral Anticoagulation Use in Postoperative and Nonpostoperative Atrial Fibrillation in Routine Clinical Practice.

BACKGROUND: The study aimed to describe the patterns and trends of initiation, discontinuation, and adherence of oral anticoagulation (OAC) in patients with new-onset postoperative atrial fibrillation (POAF), and compare with patients newly diagnosed with non-POAF. METHODS AND RESULTS: This retrospective cohort study identified patients newly diagnosed with atrial fibrillation or flutter between 2012 and 2021 using administrative claims data from OptumLabs Data Warehouse. The POAF cohort included 118 366 patients newly diagnosed with atrial fibrillation or flutter within 30 days after surgery. The non-POAF cohort included the remaining 315 832 patients who were newly diagnosed with atrial fibrillation or flutter but not within 30 days after a surgery. OAC initiation increased from 28.9% to 44.0% from 2012 to 2021 in POAF, and 37.8% to 59.9% in non-POAF; 12-month medication adherence increased from 47.0% to 61.8% in POAF, and 59.7% to 70.4% in non-POAF. The median time to OAC discontinuation was 177 days for POAF, and 242 days for non-POAF. Patients who saw a cardiologist within 90 days of the first atrial fibrillation or flutter diagnosis, regardless of POAF or non-POAF, were more likely to initiate OAC (odds ratio, 2.92 [95% CI, 2.87-2.98]; P <0.0001), adhere to OAC (odds ratio, 1.08 [95% CI, 1.04-1.13]; P <0.0001), and less likely to discontinue (odds ratio, 0.83 [95% CI, 0.82-0.85]; P <0.0001) than patients who saw a surgeon or other specialties. CONCLUSIONS: The use of and adherence to OAC were higher in non-POAF patients than in POAF patients, but they increased over time in both groups. Patients managed by cardiologists were more likely to use and adhere to OAC, regardless of POAF or non-POAF.

Relationships between adrenal insufficiency and cardiovascular outcomes in patients with atrial fibrillation, atrial flutter and paroxysmal supraventricular tachycardia.

BACKGROUND: Patients with Adrenal Insufficiency (AI) face elevated cardiovascular risks, but little remains known about arrhythmia outcomes in this context. METHOD: Analyzing the 2016-2019 Nationwide Inpatient Sample, we identified cases of Atrial Fibrillation, Atrial Flutter, and paroxysmal supraventricular tachycardia (PSVT) with a secondary diagnosis of AI. Mortality was the primary outcome while vasopressors and/or mechanical ventilation use, length of stay (LOS), and total hospitalization charges (THC) constituted secondary outcomes. Multivariate linear and logistic regression models were used to adjust for confounders. RESULTS: Among patients with Atrial Fibrillation, Atrial Flutter, and PSVT (N=1,556,769), 0.2% had AI. AI was associated with higher mortality (adjusted OR [aOR] 2.29, p=0.001), vasopressor and/or mechanical ventilation use (aOR 2.54, p<0.001), THC ($62,347 vs. $41,627, p<0.001) and longer LOS (4.4 vs. 3.2 days, p<0.001) compared to no AI. CONCLUSION: AI was associated with higher adverse outcomes in cases of Atrial Fibrillation, Atrial Flutter, and PSVT.

Association Between Family History and Early-Onset Atrial Flutter Across Racial and Ethnic Groups.

BACKGROUND: Genetic and familial contributions to early-onset atrial fibrillation are described primarily in individuals of European ancestry. However, the role of racial and familial contributions in the pathogenesis of early-onset atrial flutter (EOAFL) is unclear. METHODS AND RESULTS: In this cross-sectional study, participants were enrolled prospectively from 2015 to 2021 in multiple academic centers with a diagnosis of atrial flutter (AFL) confirmed by ECG. EOAFL was defined as a diagnosis of AFL before age 66 years with no concomitant or previous diagnosis of atrial tachyarrhythmias. Family history was adjudicated through baseline questionnaires and direct family interviews about the diagnosis of atrial tachyarrhythmias, stroke, and cardiomyopathy. The primary exposure was a positive family history in first-degree relatives, and the primary outcome was the odds of EOAFL versus late-onset AFL. A total of 909 patients were enrolled. Participants with a positive family history of atrial tachyarrhythmias were younger, less likely to be of Black race, and more likely to have EOAFL. The adjusted odds ratio (OR) for EOAFL in those with a positive family history was 1.8 (95% CI, 1.1-3.0). There was an increased odds of EOAFL in those of Black race (OR, 2.1 [95% CI, 1.4-3.2]), alcohol use (OR, 1.6 [95% CI, 1.0-2.6]), and obstructive sleep apnea (OR, 1.9 [95% CI, 1.0-3.4]). Use of cardioselective ß blockers or calcium channel blockers before the diagnosis of AFL were associated with a lower odds of EOAFL (OR, 0.5 [95% CI, 0.2-0.9]). CONCLUSIONS: These findings suggest a potentially hereditary predisposition to EOAFL across race and ethnicity, warranting further study of the genetic contributions to AFL.

Factors associated with non-fatal heart failure and atrial fibrillation or flutter within the first 30 days post COPD exacerbation: a nested case-control study.

BACKGROUND: An immediate, temporal risk of heart failure and arrhythmias after a Chronic Obstructive Pulmonary Disease (COPD) exacerbation has been demonstrated, particularly in the first month post-exacerbation. However, the clinical profile of patients who develop heart failure (HF) or atrial fibrillation/flutter (AF) following exacerbation is unclear. Therefore we examined factors associated with people being hospitalized for HF or AF, respectively, following a COPD exacerbation. METHODS: We conducted two nested case-control studies, using primary care electronic healthcare records from the Clinical Practice Research Datalink Aurum linked to Hospital Episode Statistics, Office for National Statistics for mortality, and socioeconomic data (2014-2020). Cases had hospitalization for HF or AF within 30 days of a COPD exacerbation, with controls matched by GP practice (HF 2:1;AF 3:1). We used conditional logistic regression to explore demographic and clinical factors associated with HF and AF hospitalization. RESULTS: Odds of HF hospitalization (1,569 cases, 3,138 controls) increased with age, type II diabetes, obesity, HF and arrhythmia history, exacerbation severity (hospitalization), most cardiovascular medications, GOLD airflow obstruction, MRC dyspnea score, and chronic kidney disease. Strongest associations were for severe exacerbations (adjusted odds ratio (aOR)=6.25, 95%CI 5.10-7.66), prior HF (aOR=2.57, 95%CI 1.73-3.83), age≥80 years (aOR=2.41, 95%CI 1.88-3.09), and prior diuretics prescription (aOR=2.81, 95%CI 2.29-3.45). Odds of AF hospitalization (841 cases, 2,523 controls) increased with age, male sex, severe exacerbation, arrhythmia and pulmonary hypertension history and most cardiovascular medications. Strongest associations were for severe exacerbations (aOR=5.78, 95%CI 4.45-7.50), age≥80 years (aOR=3.15, 95%CI 2.26-4.40), arrhythmia (aOR=3.55, 95%CI 2.53-4.98), pulmonary hypertension (aOR=3.05, 95%CI 1.21-7.68), and prescription of anticoagulants (aOR=3.81, 95%CI 2.57-5.64), positive inotropes (aOR=2.29, 95%CI 1.41-3.74) and anti-arrhythmic drugs (aOR=2.14, 95%CI 1.10-4.15). CONCLUSIONS: Cardiopulmonary factors were associated with hospitalization for HF in the 30 days following a COPD exacerbation, while only cardiovascular-related factors and exacerbation severity were associated with AF hospitalization. Understanding factors will help target people for prevention.

Long-term outcomes after hospitalization for atrial fibrillation or flutter.

BACKGROUND AND AIMS: Atrial fibrillation (AF) and flutter are common causes of hospitalizations but contemporary long-term outcomes following these episodes are uncertain. This study assessed outcomes up to 10 years after an acute AF or flutter hospitalization. METHODS: Patients hospitalized acutely with a primary diagnosis of AF or flutter from 2008-17 from all public and most private hospitals in Australia and New Zealand were included. Kaplan-Meier methods and flexible parametric survival modelling were used to estimate survival and loss in life expectancy, respectively. Competing risk model accounting for death was used when estimating incidence of non-fatal outcomes. RESULTS: A total of 260 492 adults (mean age 70.5 ± 14.4 years, 49.6% female) were followed up for 1 068 009 person-years (PY), during which 69 167 died (incidence rate 6.5/100 PY) with 91.2% survival at 1 year, 72.7% at 5 years, and 55.2% at 10 years. Estimated loss in life expectancy was 2.6 years, or 16.8% of expected life expectancy. Re-hospitalizations for heart failure (2.9/100 PY), stroke (1.7/100 PY), and myocardial infarction (1.1/100 PY) were common with respective cumulative incidences of 16.8%, 11.0%, and 7.1% by 10 years. Re-hospitalization for AF or flutter occurred in 21.3% by 1 year, 35.3% by 5 years, and 41.2% by 10 years (11.6/100 PY). The cumulative incidence of patients undergoing catheter ablation of AF was 6.5% at 10 years (1.2/100 PY). CONCLUSIONS: Patients hospitalized for AF or flutter had high death rates with an average 2.6-year loss in life expectancy. Moreover, re-hospitalizations for AF or flutter and related outcomes such as heart failure and stroke were common with catheter ablation used infrequently for treatment, which warrant further actions.

Prevalence and Predictors of Readmissions in Patients With Hypertrophic Cardiomyopathy and Atrial Fibrillation/Flutter.

Atrial fibrillation/flutter (AF) is the most common dysrhythmia in patients with hypertrophic cardiomyopathy (HCM). Unexplained left ventricular hypertrophy and left ventricular outflow tract obstruction are integral components of HCM pathology which can cause increased left atrial pressure and atrial myopathy contributing to the substrate for AF. We aimed to determine the impact of AF on hospital readmissions in patients with HCM. We conducted a retrospective analysis using the 2015 to 2019 Nationwide Readmission Database to analyze the effect of AF on 30-day readmission and causes of 30-day readmission in patients with HCM. We also determined the hospital, patient, and procedure-specific independent predictors of readmission in patients with HCM and AF. Of 191,235 index HCM hospitalizations, 81,390 (42.6%) had a secondary diagnosis of AF. A total of 16.9% of patients with HCM and AF were readmitted within 30 days as compared with 14% of HCM patients without AF. The presence of AF was independently associated with a higher risk of all-cause 30-day readmission (hazard ratio [HR] 1.21, 95% confidence interval [CI] 1.17 to 1.25, p <0.001). The foremost etiology of 30-day readmission in HCM patients with AF was hypertensive heart and chronic kidney disease with heart failure, whereas the foremost etiology of 30-day readmission in HCM patients without AF was sepsis. Interventions aimed toward AF management (electrical cardioversion: adjusted HR 0.91, 95% CI 0.82 to 1.01. p = 0.074, AF ablation: HR 0.92, 95% CI 0.74 to 1.13, p = 0.409, Watchman procedure: HR 1.50, 95% CI 0.16 to 14.6, p = 0.725) during index admission did not significantly impact the 30-day readmission in HCM patients with AF. Myectomy during index hospitalization (adjusted HR 0.54, 95% CI 0.34 to 0.86, p = 0.010) was most strongly associated with a lower risk of 30-day readmission in HCM patients with AF. In conclusion, in patients hospitalized for HCM, presence of AF was associated with excess risk of 30-day all-cause readmission. Interventions aimed toward HCM management, that is, myectomy rather than interventions aimed toward AF management predicted lower readmission rate in this patient population.

Incidence and patterns of atrial fibrillation after catheter ablation of typical atrial flutter-the FLUTFIB study.

AIMS: In patients with atrial flutter (AFL), ablation of the cavotricuspid isthmus (CTI) is a highly effective procedure to prevent AFL recurrence, but atrial fibrillation (AF) may occur during follow-up. The presented FLUTFIB study was designed to identify the exact incidence, duration, timely occurrence, and associated symptoms of AF after CTI ablation using continuous cardiac monitoring via implantable loop recorders. METHODS AND RESULTS: One hundred patients with AFL without prior AF diagnosis were included after CTI ablation (mean age 69.7 ± 9.7 years, 18% female) and received an implantable loop recorder for AF detection. After a median follow-up of 24 months 77 patients (77%) were diagnosed with AF episodes. Median time to first AF occurrence was 180 (43-298) days. Episodes lasted longer than 1 h in most patients (45/77, 58%). Forty patients (52%) had AF-associated symptoms.Patients with and without AF development showed similar baseline characteristics and neither HATCH- nor CHA2DS2-VASc scores were predictive of future AF episodes. Oral anticoagulation (OAC) was stopped during FU in 32 patients (32%) and was re-initiated after AF detection in 15 patients (15%). No strokes or transient ischaemic attack episodes were observed during follow-up. CONCLUSION: This study represents the largest investigation using implantable loop recorders (ILRs) to detect AF after AFL ablation and shows a high incidence of AF episodes, most of them being asymptomatic and lasting longer than 1 h. In anticipation of trials determining the duration of AF episodes that should trigger OAC initiation, these results will help to guide anticoagulation management after CTI ablation.

Association of sleep duration with atrial fibrillation/flutter mortality in the United States: a cross-sectional analysis.

BACKGROUND: The association between sleep duration and atrial fibrillation risk is poorly understood, with inconsistent findings reported by several studies. We sought to assess the association between long sleep duration and mortality due to atrial fibrillation/atrial flutter (AF/AFL). METHODS: The 2016-2020 Centers for Disease Control and Prevention (CDC) Wide-Ranging Online Data for Epidemiologic Research dataset was used to identify death records secondary to AF/AFL in the United States population. We used the 2018 Behavioral Risk Factor Surveillance System (BRFSS) dataset of sleep duration at the county level. All counties were grouped into quartiles based on the percentage of their population with long sleep duration (i.e., ≥ 7 h), Q1 being the lowest and Q4 the highest quartile. Age-adjusted mortality rates (AAMR) were calculated for each quartile. County Health Rankings for Texas were used to adjust the AAMR for comorbidities using linear regression. RESULTS: Overall, the AAMR for AF/AFL were highest in Q4 (65.9 [95% CI, 65.5-66.2] per 100,000 person-years) and lowest in Q1 (52.3 [95% CI, 52.1-52.5] per 100,000 person-years). The AAMR for AF/AFL increased stepwise from the lowest to highest quartiles of the percentage population with long sleep duration. After adjustment for the county health ranks of Texas, long sleep duration remained associated with a significantly higher AAMR (coefficient 220.6 (95% CI, 21.53-419.72, p-value = 0.03). CONCLUSIONS: Long sleep duration was associated with higher AF/AFL mortality. Increased focus on risk reduction for AF, public awareness about the importance of optimal sleep duration, and further research to elucidate a potential causal relationship between sleep duration and AF are warranted.

Localized Re-Entry Is a Frequent Mechanism of De Novo Atypical Flutter.

BACKGROUND: Limited data exist about the origins and mechanisms of atypical atrial flutter that occurs in the absence of prior ablation or surgery. OBJECTIVES: The aims of this study were to report a large cohort of patients who presented for catheter ablation of de novo atypical flutters, to identify the most common locations and mechanisms of arrhythmia, and to describe outcomes after ablation. METHODS: Demographic, electrophysiological, and outcome data were collected for patients who underwent ablation of de novo atypical flutter. RESULTS: The mechanisms of 85 atypical flutters were identified in 62 patients and localized to the left atrium (LA) in 58 and right atrium (RA) in 27. In the LA, mechanisms were classified as macro-re-entry in 29 (50%) and localized re-entry in 29 (50%), whereas in the RA, mechanisms were macro-re-entry in 8 (30%) and localized re-entry in 19 (70%) (proportion of localized re-entry in the LA vs. RA, P = 0.08). Nine patients had both localized and macro-re-entrant atypical flutters. In the LA, localized re-entry was commonly found in the anterior LA, followed by the pulmonary veins and septum. In the RA, localized re-entry was found at various sites, including the lateral or posterior RA, septum, and coronary sinus ostium. During 39.4 months (Q1-Q3: 18.2-65.8 months) of follow-up, atrial arrhythmias occurred in 66% of patients after a single ablation and in 50% after >1 ablation. Among patients who underwent repeat ablation, compared with the index arrhythmia, different tachycardia circuits or arrhythmias were documented in 13 of 18 cases (72%). CONCLUSIONS: Atypical atrial flutters in patients without prior surgery or complex ablation are often due to localized re-entry (approximately 50% in the LA and a higher frequency in the RA). Other atrial tachycardias commonly occur during long-term follow-up following ablation, suggesting progressive atrial myopathy in these patients.

Clinical Outcomes of Decompensated Heart Failure With Reduced Ejection Fraction Admissions With or Without Atrial Fibrillation and Atrial Flutter.

The aim of our retrospective study is to determine the influence of co-morbid atrial fibrillation or flutter (AF) on decompensated congestive heart failure (CHF) admissions using data from the 2020 nationwide inpatient sample. We identified 76,835 adults admitted nonelectively with decompensated CHF. After multivariate adjustment, we found decompensated heart failure with reduced ejection fraction (HFrEF) admissions with AF had 37% higher odds of in-hospital mortality, (OR 1.38 [95% CI 1.1-1.72] P < 0.01), 33% higher odds for mechanical ventilation (MV) (OR 1.33 [95% CI 1.14-1.55] P < 0.01), 39% higher odds of early MV (OR 1.39 [95% CI 1.16-1.66] P < 0.01), 54% higher odds of cardiogenic shock (OR 1.54 [95% CI 1.29-1.84] P < 0.01), 61% increased odds of mechanical circulatory support (MCS) requirement (OR 1.61 [95% CI 1.12-2.31] P < 0.02), significantly higher odds of acute renal failure (AKI) necessitating dialysis (OR 2.20 [95% CI 1.39-2.48] P < 0.01), 1-day increase in mean length of stay (LOS) (6.7 vs 5.7 days, adjusted difference: 0.99, P < 0.01), $13,281 increase in total hospitalization charges ($84,316 vs $74,279, adjusted difference: $13,281, P < 0.05) compared to the non-AF cohort. Moreover, we found decompensated heart failure with preserved ejection fraction (HFpEF) admissions with AF had a 23% increased odds of MV (OR 1.23 [95% CI 1.01-1.50] P < 0.01), 24% higher odds of early MV (OR 1.24 [95% CI 1.00-1.53] P < 0.01), 0.36 days increase in mean LOS (5.5 vs 5.2 days, adjusted difference: 0.36, P = < 0.01), but no significant difference in in-hospital mortality (OR 1.23 [95% CI 0.86-1.75] P = 0.25), cardiogenic shock (OR 1.75 [95% CI 0.96-3.19] P < 0.07), dialysis-dependent AKI (OR 0.46 [95% CI 0.18-1.17] P < 0.10), or mean total hospitalization charges ($52,086 vs $47,990, adjusted difference: $5584, P = 0.06) compared to the non-AF cohort.

Clinical characteristics and outcomes of atrial flutter in neonates.

BACKGROUND: Atrial flutter is an uncommon arrhythmia that can cause severe morbidity, including heart failure and even death in refractory cases. This study investigated the clinical characteristics, treatment, and long-term outcomes of patients with neonatal atrial flutter and its association with heart failure. METHODS: We retrospectively reviewed atrial flutter cases observed in our center between 1999 and 2021 and analyzed the clinical characteristics, treatment, and recurrence according to the presence of heart failure. RESULTS: The study comprised 15 patients with atrial flutter, with median bodyweight and gestational age of 2.7 kg, 37+4 weeks, respectively. Twelve patients were diagnosed with atrial flutter on the first day of life. The median atrial and ventricular rates were 440/min, 220/min, respectively. Four patients exhibited congestive heart failure. Episodic recurrence was noted in five patients and occurred at a higher rate in patients with congestive heart failure (p = 0.004). Antiarrhythmic drugs for maintenance treatment were administered more often in patients with heart failure (p = 0.011). Initial treatment included direct current cardioversion (n = 9), digoxin (n = 4), and observation (n = 2). Four patients treated with cardioversion experienced recurrence during the neonatal period, and none of those treated with digoxin experienced recurrence. The median follow-up duration was 7 years, during which no atrial flutter recurrence was evident. CONCLUSION: Neonates with congestive heart failure had a higher recurrence of atrial flutter. Direct current cardioversion is the most reliable treatment for neonatal atrial flutter, whereas digoxin may be a viable treatment option in refractory and recurrent cases.

Global Burden of Atrial Fibrillation and Flutter by National Income: Results From the Global Burden of Disease 2019 Database.

Background Atrial fibrillation (AF) and atrial flutter (AFL) are common conditions that can lead to significant morbidity and death. We aimed to understand the distribution and disparities of the global burden of AF/AFL as well as the underlying risk factors. Methods and Results Data on the AF/AFL burden from the Global Burden of Disease data set were analyzed for the years 1990 to 2019, with countries grouped into low, lower-middle, upper-middle, and high national income classes according to World Bank categories. Data were supplemented with World Health Organization and World Bank information. The prevalence of AF/AFL has more than doubled (+120.7%) since 1990 in all income groups, though with a larger increment in middle-income countries (+146.6% in lower-middle- and +145.2% in upper-middle-income countries). In absolute numbers, 63.4% of AF/AFL cases originate from upper-middle-income countries, although the relative prevalence is highest in high-income countries. Prevalence of AF/AFL appears to be correlated with medical doctor rate and life expectancy. The most relevant AF/AFL risk factors are unevenly distributed among income classes, with elevated blood pressure as the only risk factor that becomes less common with increasing income. The development of these risk factors differed over time. Conclusions The global burden of AF/AFL is increasing in all income groups and is more pronounced in middle-income countries, with further growth to be expected. Underdiagnosis of AF/AFL in low- and middle-income countries may contribute to lower reported prevalence. The risk factor distribution varies between income groups.

Interatrial Block Association With Adverse Cardiovascular Outcomes in Patients Without a History of Atrial Fibrillation.

BACKGROUND: Interatrial block (IAB) is associated with thromboembolism and atrial arrhythmias. However, prior studies included small patient cohorts so it remains unclear whether IAB predicts adverse outcomes particularly in context of atrial fibrillation (AF)/atrial flutter (AFL). OBJECTIVES: This study sought to determine whether IAB portends increased stroke risk in a large cohort in the presence or absence of AFAF/AFL. METHODS: We performed a 5-center retrospective analysis of 4,837,989 electrocardiograms (ECGs) from 1,228,291 patients. IAB was defined as P-wave duration ≥120 ms in leads II, III, or aVF. Measurements were extracted as .XML files. After excluding patients with prior AF/AFL, 1,825,958 ECGs from 458,994 patients remained. Outcomes were analyzed using restricted mean survival time analysis and restricted mean time lost. RESULTS: There were 86,317 patients with IAB and 355,032 patients without IAB. IAB prevalence in the cohort was 19.6% and was most common in Black (26.1%), White (20.9%), and Hispanic (18.5%) patients and least prevalent in Native Americans (9.2%). IAB was independently associated with increased stroke probability (restricted mean time lost ratio coefficient [RMTLRC]: 1.43; 95% CI: 1.35-1.51; tau = 1,895), mortality (RMTLRC: 1.14; 95% CI: 1.07-1.21; tau = 1,924), heart failure (RMTLRC: 1.94; 95% CI: 1.83-2.04; tau = 1,921), systemic thromboembolism (RMTLRC: 1.62; 95% CI: 1.53-1.71; tau = 1,897), and incident AF/AFL (RMTLRC: 1.16; 95% CI: 1.10-1.22; tau = 1,888). IAB was not associated with stroke in patients with pre-existing AF/AFL. CONCLUSIONS: IAB is independently associated with stroke in patients with no history of AF/AFL even after adjustment for incident AF/AFL and CHA2DS2-VASc score. Patients are at increased risk of stroke even when AF/AFL is not identified.

Right atrial dysfunction is associated with atrial arrhythmias in adults with repaired tetralogy of fallot.

BACKGROUND: Adults with repaired tetralogy of Fallot (TOF) have right atrial (RA) remodeling and dysfunction, and RA function can be measured using speckle tracking echocardiography. There are limited data about the role of RA strain imaging for risk stratification in this population. We hypothesized that RA reservoir strain can identify TOF patients at risk of developing atrial arrhythmia. To test this hypothesis, we assessed the relationship between RA reservoir strain and atrial arrhythmias in adults with repaired TOF. METHOD: Retrospective cohort study of adults with repaired TOF, and no prior history of atrial arrhythmias. Atrial arrhythmia was defined as atrial fibrillation, atrial flutter/atrial tachycardia, and categorized as new-onset versus recurrent atrial arrhythmias. RESULTS: We identified 426 patients (age 33 ± 12 years; males 208 (49%)) that met the inclusion criteria. The mean RA reservoir strain, conduit strain, and booster strain were 34 ± 11%, 20 ± 9%, and 15 ± 12%, respectively. Of 426 patients, 73 (17%) developed new-onset atrial arrhythmias (atrial flutter/tachycardia n = 42; atrial fibrillation n = 31); annual incidence 1.9%. RA reservoir strain was associated with new-onset atrial arrhythmias (adjusted HR 0.95, 95% CI 0.93-0.97) after multivariable adjustment. Of 73 patients with new-onset atrial arrhythmia, 41 (56%) had recurrent atrial arrhythmia (atrial flutter/tachycardia n = 18; atrial fibrillation n = 23); annual incidence 11.2%. Similarly, RA reservoir strain was associated with recurrent atrial arrhythmias (adjusted HR 0.92, 95% CI 0.88-0.96) after multivariable adjustment. CONCLUSIONS: RA strain indices can identify patients at risk for atrial arrhythmias, and this can in turn, be used to guide the type/intensity of therapy in such patients.

Effect of dronedarone vs. placebo on atrial fibrillation progression: a post hoc analysis from ATHENA trial.

AIMS: This post hoc analysis of the ATHENA trial (NCT00174785) assessed the effect of dronedarone on the estimated burden of atrial fibrillation (AF)/atrial flutter (AFL) progression to presumed permanent AF/AFL, and regression to sinus rhythm (SR), compared with placebo. METHODS AND RESULTS: The burden of AF/AFL was estimated by a modified Rosendaal method using available electrocardiograms (ECG). Cumulative incidence of permanent AF/AFL (defined as ≥6 months of AF/AFL until end of study) or permanent SR (defined as ≥6 months of SR until end of study) were calculated using Kaplan-Meier estimates. A log-rank test was used to assess statistical significance. Hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were estimated using a Cox model, adjusted for treatment group. Of the 4439 patients included in this analysis, 2208 received dronedarone, and 2231 placebo. Baseline and clinical characteristics were well balanced between groups. Overall, 304 (13.8%) dronedarone-treated patients progressed to permanent AF/AFL compared with 455 (20.4%) treated with placebo (P < 0.0001). Compared with those receiving placebo, patients receiving dronedarone had a lower cumulative incidence of permanent AF/AFL (log-rank P < 0.001; HR: 0.65; 95% CI: 0.56-0.75), a higher cumulative incidence of permanent SR (log-rank P < 0.001; HR: 1.19; 95% CI: 1.09-1.29), and a lower estimated AF/AFL burden over time (P < 0.01 from Day 14 to Month 21). CONCLUSION: These results suggest that dronedarone could be a useful antiarrhythmic drug for early rhythm control due to less AF/AFL progression and more regression to SR vs. placebo, potentially reflecting reverse remodeling. CLINICAL TRIAL REGISTRATION: NCT00174785.

Global burden of atrial fibrillation/atrial flutter and its attributable risk factors from 1990 to 2019.

AIMS: The aim of this study was to estimate the global burden of atrial fibrillation (AF)/atrial flutter (AFL) and its attributable risk factors from 1990 to 2019. METHODS AND RESULTS: The data on AF/AFL were retrieved from the Global Burden of Disease Study (GBD) 2019. Incidence, disability-adjusted life years (DALYs), and deaths were metrics used to measure AF/AFL burden. The population attributable fractions (PAFs) were used to calculate the percentage contributions of major potential risk factors to age-standardized AF/AFL death. The analysis was performed between 1990 and 2019. Globally, in 2019, there were 4.7 million [95% uncertainty interval (UI): 3.6 to 6.0] incident cases, 8.4 million (95% UI: 6.7 to 10.5) DALYs cases, and 0.32 million (95% UI: 0.27 to 0.36) deaths of AF/AFL. The burden of AF/AFL in 2019 and their temporal trends from 1990 to 2019 varied widely due to gender, Socio-Demographic Index (SDI) quintile, and geographical location. Among all potential risk factors, age-standardized AF/AFL death worldwide in 2019 were primarily attributable to high systolic blood pressure [34.0% (95% UI: 27.3 to 41.0)], followed by high body mass index [20.2% (95% UI: 11.2 to 31.2)], alcohol use [7.4% (95% UI: 5.8 to 9.0)], smoking [4.3% (95% UI: 2.9 to 5.9)], diet high in sodium [4.2% (95% UI: 0.8 to 10.5)], and lead exposure [2.3% (95% UI: 1.3 to 3.4)]. CONCLUSION: Our study showed that AF/AFL is still a major public health concern. Despite the advancements in the prevention and treatment of AF/AFL, especially in regions in the relatively SDI quintile, the burden of AF/AFL in regions in lower SDI quintile is increasing. Since AF/AFL is largely preventable and treatable, there is an urgent need to implement more cost-effective strategies and interventions to address modifiable risk factors, especially in regions with high or increased AF/AFL burden.

Right atrial tachycardia after atrial fibrillation ablation: prevalence, clinical characteristics, electrophysiological mechanisms, and long-term outcomes.

BACKGROUND: This study aims to evaluate the prevalence, clinical characteristics, electrophysiological mechanisms, and long-term outcomes of right atrial tachycardia (AT) in patients who underwent ablation for atrial fibrillation (AF). METHODS: From March 2010 to December 2020, 220 consecutive patients undergoing index AF ablation were referred for post-ablation AT recurrence. Thirty-five patients (35/220, 15.9%) with right AT recurrence (25 men; mean age 59.3 ± 10.2 years) were enrolled. These patients were divided into groups with right ATs exclusively (group 1) and right combined with left ATs (group 2). RESULTS: Fifty-three ATs were mapped in all patients, with thirty-nine ATs originating from the right atrium. The detailed distribution of all right ATs was 22 in the cavo-tricuspid isthmus (CTI), 6 in the ostium of superior vein cava (SVC), 4 in the right free wall, 4 in the right anterior atrial septum, 2 in coronary sinus ostium, and 1 in crista terminalis. Group 2 had a significantly higher incidence of typical atrial flutter (AFL) than group 1 (11/12, 90.9% vs. 12/24, 50.0%, P = 0.03). During the mean follow-up of 43.6 ± 25.2 months after the index AT ablation, the recurrence rate of AT/AF was 22.9% (8/35), and it was lower in group 1 than in group 2 (8.3% vs. 54.5%, P = 0.01). CONCLUSION: Right AT is relatively less common post-AF ablation. The CTI-dependent AFL and the ostium of SVC-derived focal AT constituted the major components of right ATs, suggesting the importance of ablation- and anatomy-related arrhythmogenic effects in the right atrium.