Association between high-density mapping of atypical atrial flutter, clinical outcomes and healthcare utilization.

BACKGROUND: Success of atypical atrial flutter (AAFL) ablation has historically been limited by difficulty mapping the complex re-entrant circuits involved. While high-density (HD) mapping has become commonplace in clinical practice, there are limited data on outcomes of HD versus non-HD mapping for AAFL ablation. OBJECTIVE: To compare clinical outcomes and healthcare utilization using HD mapping versus non-HD mapping for AAFL ablation. METHODS: Retrospective analysis of all AAFL procedures between 2005 and 2022 at an academic medical center was conducted. Procedures utilizing a 16-electrode HD Grid catheter and Precision mapping system were compared to procedures using prior generation 10-20 electrode spiral catheters and the Velocity system (Abbott, IL). Cox regression models and Poisson regression models were utilized to examine procedural and healthcare utilization outcomes. Models were adjusted for left ventricular ejection fraction, CHA2DS2-VASc, and history of prior ablation. RESULTS: There were 108 patients (62% HD mapping) included in the analysis. Baseline clinical characteristics were similar between groups. Use of HD mapping was associated with a higher rate of AAFL circuit delineation (92.5% vs. 76%; p = .014) and a greater adjusted procedure success rate, defined as non-inducibility at procedure end, (aRR (95% CI) 1.26 (1.02-1.55) p = .035) than non-HD mapping. HD mapping was also associated with a lower rate of ED visits (aIRR (95% CI) 0.32 (0.14-0.71); p = .007) and hospitalizations (aIRR (95% CI) 0.32 (0.14-0.68); p = .004) for AF/AFL/HF through 1 year. While there was a lower rate of recurrent AFL through 1 year among HD mapping cases (aHR (95% CI) 0.60 (0.31-1.16) p = .13), statistical significance was not met likely due to the low sample size and higher rate of ambulatory rhythm monitoring in the HD group (61% vs. 39%, p = .025). CONCLUSION: Compared to non-HD mapping, AAFL ablation with HD mapping is associated with improvements in the ability to define the AAFL circuit, greater procedural success, and a reduction in the number of ED visits and hospitalization for AF/AFL/HF.

Clinical outcomes of catheter ablation for atrial fibrillation, atrial flutter, and atrial tachycardia in wild-type transthyretin amyloid cardiomyopathy: a proposed treatment strategy for catheter ablation in each arrhythmia.

AIMS: Wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM) is often accompanied by atrial fibrillation (AF), atrial flutter (AFL), and atrial tachycardia (AT), which are difficult to control because beta-blockers and antiarrhythmic drugs can worsen heart failure (HF). This study aimed to investigate the outcomes of catheter ablation (CA) for AF/AFL/AT in patients with ATTRwt-CM and propose a treatment strategy for CA. METHODS AND RESULTS: A cohort study was conducted on 233 patients diagnosed with ATTRwt-CM, including 54 who underwent CA for AF/AFL/AT. The background of each arrhythmia and the details of the CA and its outcomes were investigated. The recurrence-free rate of AF/AFL/AT overall in ATTRwt-CM patients with multiple CA was 70.1% at 1-year, 57.6% at 2-year, and 44.0% at 5-year follow-up, but CA significantly reduced all-cause mortality [hazard ratio (HR): 0.342, 95% confidence interval (CI): 0.133-0.876, P = 0.025], cardiovascular mortality (HR: 0.378, 95% CI: 0.146-0.981, P = 0.045), and HF hospitalization (HR: 0.488, 95% CI: 0.269-0.889, P = 0.019) compared with those without CA. There was no recurrence of the cavotricuspid isthmus (CTI)-dependent AFL, non-CTI-dependent simple AFL terminated by one linear ablation, and focal AT originating from the atrioventricular (AV) annulus or crista terminalis eventually. Twelve of 13 patients with paroxysmal AF and 27 of 29 patients with persistent AF did not have recurrence as AF. However, all three patients with non-CTI-dependent complex AFL not terminated by a single linear ablation and 10 of 13 cases with focal AT or multiple focal ATs originating beyond the AV annulus or crista terminalis recurred even after multiple CA. CONCLUSION: The outcomes of CA for ATTRwt-CM were acceptable, except for multiple focal AT and complex AFL. Catheter ablation may be aggressively considered as a treatment strategy with the expectation of improving mortality and hospitalization for HF.

Atrial and Ventricular Arrhythmia in Adults With Shone Complex: A Single-Center Cohort Study.

Background: Multilevel obstruction in left ventricular inflow and outflow predisposes to arrhythmias in Shone's complex (SC). Objectives: The purpose of this study was to study the prevalence and outcomes (heart failure [HF] hospitalization, cardiac transplant, death) of cardiac arrhythmias in adults with SC. Methods: Adults with SC (defined as ≥2 lesions out of supramitral ring, parachute mitral valve, subvalvular/valvular aortic stenosis (AS), and aortic coarctation) seen at Mayo Clinic between January 1999 and March 2020 were identified and evaluated for the presence of sustained atrial fibrillation, atrial flutter, and ventricular arrhythmias (VA). Kaplan-Meier survival analysis was used to calculate the occurrence of these arrhythmias. Results: Seventy-three patients with SC (mean age at first visit 33 ± 13 years) were identified. Most common anomalies were valvular AS (88%), coarctation (85%), parachute mitral valve (44%), subvalvular AS (44%), and supramitral ring (25%). Atrial arrhythmias were diagnosed in 24 patients (33%) at a mean age of 34.6 ± 12.7 years. Patients with atrial fibrillation and atrial flutter had higher number of surgeries, left atrial size, right ventricular systolic pressure, and HF hospitalizations. A rhythm control approach was used in majority of patients (75% on antiarrhythmic drugs and 50% underwent catheter ablation). Sustained VA occurred in 6 of 73 patients of whom 4 had an ejection fraction <40%. Death and cardiac transplantation occurred in 11 and 3 patients, respectively, during a median follow-up of 7.3 ± 6.0 years. Conclusions: In adults with SC, atrial arrhythmias occurred in one-third of patients, were associated with more HF hospitalizations, and frequently required rhythm control. Prevalence of sustained VA was 8% and implantable cardioverter-defibrillator implantation should be considered in those with reduced ejection fraction.

Case report of a double-wave re-entry atrial flutter in a patient with atrial cardiomyopathy.

Background: Double-wave macrore-entry is a rare mechanism of atrial tachycardia with limited documentation in the literature. We present a three-dimensional documentation of a double-wave 'typical' atrial flutter in a patient with extensive atrial cardiomyopathy. Case summary: A 78-year-old female with a history of atrial cardiomyopathy and dual-chamber pacemaker for sinus node disease presented with palpitations and incessant atrial flutter. Electrophysiological study revealed a regular tachycardia with a cycle length (TCL) of 230 ms, with proximal to distal coronary sinus (CS) activation. Three-dimensional mapping identified two independent wavefronts circulating the cavotricuspid isthmus (CTI), each with a TCL of 460 ms. Cavotricuspid isthmus ablation resulted in conversion into a distinct tachycardia with left atrial roof origin. Linear ablation in this location slowed the TCL to 435 ms with concentric CS activation and another CTI dependent atrial flutter was mapped, this time with only one wavefront of activation. Further ablation with a second, more lateral, line in the CTI led to tachycardia interruption. Given the extensive atrial scarring and high arrhythmic recurrence risk, atrioventricular node ablation was performed. Discussion: Double-wave re-entrant tachycardias were primarily observed in experimental models, precipitating acceleration of ventricular and supraventricular tachycardias via extrastimulation. In our case, there is documentation of a spontaneous double-wave of activation around the CTI, representing the first documented double-wave 'typical' atrial flutter. Unlike other cases in the literature, the two wavefronts were equidistant, which resulted in a regular tachycardia with TCL that was half of the single-wave cycle length. Three-dimensional propagation mapping was essential to visualize the two distinct wavefronts.

Tachycardia-Induced Cardiomyopathy in an Infant with Atrial Flutter and Prolonged Recovery of Cardiac Function.

Background: Tachycardia-induced cardiomyopathy (TIC) is caused by prolonged tachycardia, leading to left ventricular dilatation and systolic dysfunction with heart failure. Although TIC is more common in adults, it is rare in early infancy. Methods: Clinical testing was performed as part of medical evaluation and management. Next-generation sequencing (NGS) was conducted for a patient with TIC. A literature review on TIC was also conducted. Results: The case involved a 5-month-old infant referred to the hospital due to symptoms of heart failure lasting at least two months. The infant's heart rate was 200 beats per minute, the left ventricular ejection fraction fell below 14%, and electrocardiograms showed atrial flutter, suggesting TIC. After cardioversion, there was no recurrence of atrial flutter, and cardiac function improved 98 days after tachycardia arrest. The NGS did not identify any pathogenic variants. The literature review identified eight early infantile cases of TIC. However, no previous reports described a case with such a prolonged duration of TIC as ours. Conclusions: This is the first report of a case of prolonged TIC in a child with the documented time to recover normal cardiac function. The improvement of cardiac function depends on the duration of TIC. Early recognition and intervention in TIC are essential to improve outcomes for infantile patients, as timely treatment offers the potential for recovery.

Fasciculoventricular accessory pathway masked extensive atrioventricular conduction system disease in a patient with PRKAG2 syndrome.

A 23-year-old male with a history of ventricular pre-excitation and atrial flutter presented for evaluation after recurrent syncope. The possible mechanism of syncope erroneously attributed to pre-excited atrial flutter with fast heart rates in the first hospitalization. The patient was found to have advanced heart block and PRKAG2 genetic mutation in the second hospitalization. The genetic findings and clinical features are consistent with PRKAG2 syndrome (PS). PS is a rare, autosomal dominant inherited disease, characterized by ventricular pre-excitation, supraventricular tachycardia, and cardiac hypertrophy. It is frequently followed by atrial-fibrillation-induced ventricular fibrillation and advanced heart blocks. An accurate differential diagnosis of syncope is important because of the different arrhythmic features and clinical course of PS.

Atrial fibrillation and flutter and ocular diseases. The Ural eye and medical study and the Ural very old study.

PURPOSE: To assess associations between atrial fibrillation/atrial flutter (AF) and ocular parameters and diseases. METHODS: The population-based Ural Eye and Medical Study (UEMS) and the Ural Very Old Study (UVOS) included 4894 individuals (age: 40+ years) and 835 individuals (age: 85+ years), respectively. RESULTS: In the UEMS, AF prevalence (80/4894; 1.6%; 95% CI: 1.3, 2.0) increased from 1/1029 (0.1%) in the age group of 40 to <50 years to 29/619 (4.7%) and 12/159 (7.5%) in the age groups of 70 to <80 years and 80+ years, respectively. Higher AF prevalence correlated with older age (OR: 1.08; 95% CI: 1.04, 1.12; p < 0.001), urban region of habitation (OR: 1.08; 95% CI: 1.04, 1.12; p < 0.001), higher prevalence of cardiovascular disease/stroke (OR: 2.50; 95% CI: 1.32, 4.72; p < 0.001) and lower prevalence of neck pain (OR: 0.35; 95% CI: 0.14, 0.85; p = 0.02), higher serum concentration of bilirubin (OR: 1.03; 95% CI: 1.02, 1.05; p < 0.001) and lower prothrombin index (OR: 0.96; 95% CI: 0.93, 0.99; p = 0.003), higher stage of arterial hypertension (OR: 1.52; 95% CI: 1.01, 2.28; p = 0.04) and higher ankle-brachial index (OR: 22.1; 95% CI: 4.45, 1.10; p < 0.001). In that model, AF prevalence was not associated with ocular parameters such as intraocular pressure (p = 0.52), retinal nerve fibre layer thickness (p = 0.70), refractive error (p = 0.13), axial length (p = 0.14), nuclear cataract degree (p = 0.50) and prevalence (p = 0.40), cortical cataract degree (p = 0.43) and presence (p = 0.17), lens pseudoexfoliation (p = 0.58), status after cataract surgery (p = 0.38), age-related macular degeneration prevalence (p = 0.63), open-angle glaucoma presence (p = 0.90) and stage (p = 0.55), angle-closure glaucoma prevalence (p = 0.99) and stage (p = 0.99), diabetic retinopathy prevalence presence (p = 0.37) and stage (p = 0.32), and myopic macular degeneration (p = 0.98). In the UVOS, similar results were obtained. CONCLUSIONS: In these multi-ethnic populations from Russia, AF prevalence was not associated with any major ocular disease and may not play a major role in the pathogenesis of these disorders.

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.

Atypical atrial flutter ablation: follow-up and predictors of arrhythmia recurrence.

BACKGROUND: Ablation techniques have evolved greatly with advances in high-density 3D mapping systems over the last few years. Some patients develop atypical atrial flutter (AAFL) after pulmonary vein isolation (PVI). The data regarding follow-up after AAFL ablation as well as predictors of arrhythmia recurrence are lacking. This analysis aims to report procedure success rates and establish predictors of long-term success. METHODS AND RESULTS: This retrospective cohort study included 45 patients (median age: 69 years; 40% female) who qualified for their first AAFL after PVI. The procedures were performed with the use of conventional ablation-index-guided ThermoCool Smarttouch SF and QDOT MICRO catheters. Freedom from arrhythmia recurrence was used as a primary end point. After 52 weeks of follow-up, 60% of patients suffered from arrhythmia recurrence, but over 70% of the studied cohort reported symptom improvement. In multivariate analysis, class I antiarrhythmics prescription (HR = 0.24 [95% CI 0.06-0.94], p = 0.04) was associated with the lack of arrhythmia recurrence during the follow-up, while cardioversion during procedure was associated with increased risk of arrhythmia recurrence (HR = 7.05 [95% CI 2.09-23.72], p = 0.002). CONCLUSIONS: Long-term success of AAFL ablation procedures is not satisfactory despite improvement in symptoms. Class I antiarrhythmics prescription at the discharge contributes to higher chances of sinus rhythm maintenance, whereas cardioversion during the procedure is related to increased risk of arrhythmia recurrence.

Development and validation of the Atri-Risk Conduction Index risk score to predict risk of atrial fibrillation after typical atrial flutter ablation.

BACKGROUND: Identification of patients at risk for atrial fibrillation (AF) after typical atrial flutter (tAFL) ablation is important to guide monitoring and treatment. OBJECTIVE: The purpose of this study was to create and validate a risk score to predict AF after tAFL ablation METHODS: We identified patients who underwent tAFL ablation with no AF history between 2017 and 2022 and randomly allocated to derivation and validation cohorts. We collected clinical variables and measured conduction parameters in sinus rhythm on an electrophysiology recording system (CardioLab, GE Healthcare). Univariate and multivariate logistic regressions (LogR) were used to evaluate association with AF development. RESULTS: A total of 242 consecutive patients (81% male; mean age 66 ± 11 years) were divided into derivation (n =142) and validation (n = 100) cohorts. Forty-two percent developed AF over median follow-up of 330 days. In multivariate LogR (derivation cohort), proximal to distal coronary sinus time (pCS-dCS) ≥70 ms (odds ratio [OR] 16.7; 95% confidence interval [CI] 5.6-49), pCS time ≥36 ms (OR 4.5; 95% CI 1.5-13), and CHADS2-VASc score ≥3 (OR 4.3; 95% CI 1.6-11.8) were independently associated with new AF during follow-up. The Atri-Risk Conduction Index (ARCI) score was created with 0 as minimal and 4 as high-risk using pCS-dCS ≥70 ms = 2 points; pCS ≥36 ms = 1 point; and CHADS2-VASc score ≥3 = 1 point. In the validation cohort, 0% of patients with ARCI score = 0 developed AF, whereas 89% of patients with ARCI score = 4 developed AF. CONCLUSION: We developed and validated a risk score using atrial conduction parameters and clinical risk factors to predict AF after tAFL ablation. It stratifies low-, moderate-, and high-risk patients and may be helpful in individualizing approaches to AF monitoring and anticoagulation.

Global, regional, and national burden of atrial fibrillation/flutter related to metabolic risks over three decades: estimates from the global burden of disease study 2019.

AIMS: Atrial fibrillation/atrial flutter (AF/AFL) remains a significant public health concern on a global scale, with metabolic risks playing an increasingly prominent role. This study aimed to investigate comprehensive epidemiological data and trends concerning the metabolic risks related-AF/AFL burden based on the data from the Global Burden of Disease (GBD) study 2019. METHODS & RESULTS: The analysis of disease burden focused on numbers, age-standardized rates (ASR) of deaths, disability-adjusted life years (DALYs), and estimated annual percentage change (EAPC), while considering factors of age, sex, sociodemographic index (SDI), and locations. In 2019, there was a culmination of 137 179 deaths and 4 099 146 DALYs caused by metabolic risks related-AF/AFL worldwide, with an increase of 162.95% and 120.30% respectively from 1990. High and high-middle SDI regions predominantly carried the burden of AF/AFL associated with metabolic risks, while a shift towards lower SDI regions had been occurring. Montenegro had the highest recorded death rate (7.6 per 100 000) and DALYs rate (146.3 per 100 000). An asymmetrically inverted V-shaped correlation was found between SDI and deaths/DALYs rates. Moreover, females and the elderly exhibited higher AF/AFL burdens, and young adults (over 40 years old) also experienced an annual increase. CONCLUSIONS: The global AF/AFL burden related to metabolic risks has significantly increased over past three decades, with considerable spatiotemporal, gender-based, and age-related heterogeneity. These findings shed valuable light on the trends in the burden of metabolic risks related-AF/AFL, and offered insights into corresponding strategies.

Comparison of anterior mitral line and mitral isthmus line for ablation of mitral annular flutter.

BACKGROUND: Mitral annular flutter (MAF) is the most common left atrial macro-reentrant arrhythmia following catheter ablation of atrial fibrillation (AF). The best ablation approach for this arrhythmia remains unclear. METHODS: This single-center, retrospective study sought to compare the acute and long-term outcomes of patients with MAF treated with an anterior mitral line (AML) versus a mitral isthmus line (MIL). Acute ablation success, complication rates, and long-term arrhythmia recurrence were compared between the two groups. RESULTS: Between 2015 and 2021, a total of 81 patients underwent ablation of MAF (58 with an AML and 23 with a MIL). Acute procedural success defined as bidirectional block was achieved in 88% of the AML and 91% of the MIL patients respectively (p = 1.0). One year freedom from atrial arrhythmias was 49.5% versus 77.5% and at 4 years was 24% versus 59.6% for AML versus MIL, respectively (hazard ratio [HR]: 0.38, confidence interval [CI]: 0.17-0.82, p = .009). Fewer patients in the MIL group had recurrent atrial flutter when compared to the AML group (HR: 0.32, CI: 0.12-0.83, p = .009). The incidence of recurrent AF, on the other side, was not different between both groups (21.7% vs. 18.9%; p = .76). There were no serious adverse events in either group. CONCLUSION: In this retrospective study of patients with MAF, a MIL compared to AML was associated with a long-term reduction in recurrent atrial arrhythmias driven by a reduction in macroreentrant atrial flutters.

Anatomical and Electrophysiological Characteristics of Dual-Loop Re-Entry in Atypical Atrial Flutter: Implications for Mapping and Catheter Ablation.

Background: Atypical atrial flutter (AFL) can be challenging to ablate, especially when involving dual-loop re-entry. We sought to assess the electroanatomical characteristics of single- and dual-loop AFLs in patients undergoing catheter ablation. Methods: We analyzed 25 non-cavotricuspid isthmus-dependent macro-re-entrant AFL in 19 consecutive patients. Three-dimensional high-density activation mapping was performed, and active re-entry loops were confirmed by entrainment mapping. Results: Of 25 AFLs (24 left, 1 right atrial), 13 (52%) exhibited dual-loop re-entry. The most common circuits included, in 6/13 (46% of dual loops), a perimitral re-entry with a second loop around the right/left pulmonary veins (PV) and, in 6/13 (46%), involved a right PV ostium with a second loop around either a functional conduction block or another PV. Ablation at the common isthmus of dual-loop AFLs and at the critical isthmus of single-loop AFLs terminated the arrhythmia more frequently than ablation at a secondary isthmus of dual-loop AFLs (5/6 (83%) and 8/11 (73%) versus 1/8 (13%), respectively, p = 0.013). Conclusions: More than half of AFLs exhibited a dual-loop re-entrant mechanism. Most critical isthmuses were found at the mitral isthmus, the left atrial roof or right PV ostia. Ablation targeting the common isthmus resulted in a higher termination rate.

Atrial placement of Aveir-VR leadless pacemaker in a patient with complex cardiac anatomy.

Leadless pacemakers have provided new treatment modalities that can be especially useful in patients with complex cardiac anatomy and contraindications toward other pacemaker approaches. The Aveir™ single-chamber (VR) leadless pacemaker (LP) (Abbott Laboratories, Chicago, IL) is a recently approved device that can be placed in the right ventricle for patients with bradycardia. In this case, we present a novel use for the device through placement in the atrium to control atrial flutter in a patient with a hypoplastic right ventricle.

Radiofrequency atrial flutter and atrial fibrillation ablation in a patient with deep brain stimulation.

Radiofrequency ablation for atrial fibrillation or atrial flutter is feasible in patients with deep brain stimulation but with extreme caution given the possibility of life-threatening complications.

Perils of reduced dose apixaban in atrial fibrillation/flutter - A case report with a brief literature review.

Patients with atrial fibrillation/atrial flutter (AF) are notoriously predisposed to thromboembolic events secondary to the development of thrombi within the left atrium of the heart. AF accompanied by a fairly decent CHA2DS2-VASc score is a known indication for full anticoagulation, frequently with direct oral anticoagulants (DOACs), such as apixaban. Following extensive studies weighing the benefits of anticoagulation versus risks of major bleeding, patients meeting two or more of the dose-reduction criteria (age ≥80 years, weight ≤60 kg, and/or creatinine ≥ 1.5 mg/dL) require appropriate step-down to a reduced dose of apixaban. However, with rising concern for bleeding complications, many physicians are found to have been reducing the dose of apixaban despite the patient not completely meeting the defined criteria. Our study particularly emphasizes the risk of significantly increased thromboembolic complications in the setting of sub-therapeutic anticoagulation, in patients with both appropriately and inappropriately reduced doses of apixaban.

Validity of International Classification of Diseases, Tenth Revision, Codes for Atrial Fibrillation/Flutter in Critically Ill Patients with Sepsis.

BACKGROUND: Atrial fibrillation (AF) and atrial flutter (AFL) are frequently seen in critically ill sepsis patients and are associated with poor outcomes. There is a need for further research, however, studies are limited due to challenges in identifying patient cohorts. Administrative data using the International Classification of Diseases, Tenth Revision (ICD-10) are routinely used for identifying disease cohorts in large datasets. However, the validity of ICD-10 for AF/AFL remains unexplored in these populations. METHODS: This validation study included 6,554 adults with sepsis and septic shock admitted to the intensive care unit. We sought to determine whether ICD-10 coding could accurately identify patients with and without AF/AFL compared to manual chart review. We also evaluated whether the date of ICD-10 code entry could distinguish prevalent from incident AF/AFL, presuming codes dated during the index admission to be incident AF/AFL. A manual chart review was performed on 400 randomly selected patients for confirmation of AF/AFL, and validity was measured using sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). RESULTS: Among the 400 randomly selected patients, 293 lacked ICD-10 codes for AF/AFL. The manual chart review confirmed the absence of AF/AFL in 286 patients (NPV 97.3%, specificity 99.7%). Among the 107 patients with ICD-10 codes for AF/AFL, 106 were confirmed to have AF/AFL by manual chart review (PPV 99.1%, sensitivity 93.0%). Out of the 114 patients with confirmed AF/AFL, 44 had ICD-10 codes dated during the index admission. All 44 were confirmed to have AF/AFL, however, 18 patients had prior documentation of AF/AFL (incident AF/AFL: PPV 59.1%). Specificity for incident (95.1%) and prevalent (99.7%) AF/AFL were high; however, sensitivity was 76.5% and 77.5%, respectively. DISCUSSION/CONCLUSION: ICD-10 codes perform well in identifying clinical AF/AFL in critically ill sepsis. However, their temporal specificity in distinguishing incidents from prevalent AF/AFL is limited.