Atrial Fibrillation Rhythm Research Articles

Automated Atrial Fibrillation Diagnosis by Echocardiography without ECG: Accuracy and Applications of a New Deep Learning Approach.

Automated rhythm detection on echocardiography through artificial intelligence (AI) has yet to be fully realized. We propose an AI model trained to identify atrial fibrillation (AF) using apical 4-chamber (AP4) cines without requiring electrocardiogram (ECG) data. Transthoracic echocardiography studies of consecutive patients ≥ 18 years old at our tertiary care centre were retrospectively reviewed for AF and sinus rhythm. The study was first interpreted by level III-trained echocardiography cardiologists as the gold standard for rhythm diagnosis based on ECG rhythm strip and imaging assessment, which was also verified with a 12-lead ECG around the time of the study. AP4 cines with three cardiac cycles were then extracted from these studies with the rhythm strip and Doppler information removed and introduced to the deep learning model ResNet(2+1)D with an 80:10:10 training-validation-test split ratio. 634 patient studies (1205 cines) were included. After training, the AI model achieved high accuracy on validation for detection of both AF and sinus rhythm (mean F1-score = 0.92; AUROC = 0.95). Performance was consistent on the test dataset (mean F1-score = 0.94, AUROC = 0.98) when using the cardiologist's assessment of the ECG rhythm strip as the gold standard, who had access to the full study and external ECG data, while the AI model did not. AF detection by AI on echocardiography without ECG appears accurate when compared to an echocardiography cardiologist's assessment of the ECG rhythm strip as the gold standard. This has potential clinical implications in point-of-care ultrasound and stroke risk stratification.

Metabolomics and Biomarkers for Paroxysmal and Persistent Atrial Fibrillation.

Atrial fibrillation (AF) is the most common type of arrhythmia worldwide and is associated with serious complications. This study investigated the metabolic biomarkers associated with AF and the differences in metabolomics and associated metabolic biomarkers between paroxysmal AF (AFPA) and persistent AF. Plasma samples were prospectively collected from patients with AF and patients in sinus rhythm with negative coronary angiography. The patients were divided into 3 groups: AFPA, persistent AF, and sinus rhythm (N=54). Metabolomics (n=36) using ultra-high-performance liquid chromatography mass spectrometry was used to detect differential metabolites that were validated in a new cohort (n=18). The validated metabolites from the validation phase were further analyzed by receiver operating characteristic. Among the 36 differential metabolites detected by omics assay, 4 were successfully validated with area under the curve >0.8 (P<0.05). Bioinformatics analysis confirmed the enrichment pathways of unsaturated fatty acid biosynthesis, glyoxylate and dicarboxylate metabolism, and carbon metabolism. Arachidonic acid was a potential biomarker of AFPA, glycolic acid and L-serine were biomarkers of AFPA and persistent AF, and palmitelaidic acid was a biomarker of AFPA. In this metabolomics study, we detected 36 differential metabolites in AF, and 4 were validated with high sensitivity and specificity. These differential metabolites are potential biomarkers for diagnosis and monitoring of disease course. This study therefore provides new insights into the precision diagnosis and management of AF.

Intraoperative atrial rhythm changes during atrial fibrillation catheter ablation in patients with arterial hypertension and coronary artery disease

Atrial fibrillation is a rhythm disorder with an extensive etiology and not fully understood pathogenesis. Catheter ablation is an effective way to control the rhythm of atrial fibrillation. The results of catheter ablation differ in patients with various comorbidities of the cardiovascular system. Intraoperative changes in the atrial rhythm can be a criterion for the long-term effectiveness of the operation or determine the need for additional effects.Aim: To assess intraoperative changes in atrial rhythm during catheter ablation of atrial fibrillation in patients with concomitant pathology of the cardiovascular system.Methodology and research methods. The results of catheter ablation of 451 patients with paroxysmal and persistent atrial fibrillation were analyzed retrospectively for the period from 2016 to 2017. After clinical and anamnestic data analysis, 151 patients with primary isolation of the pulmonary veins were selected. Depending on the concomitant pathology of the cardiovascular system, patients were divided into 3 groups: group 1 – with idiopathic atrial fibrillation, group 2 – atrial fibrillation in combination with isolated essential arterial hypertension and group 3 – atrial fibrillation in combination with ischemic heart disease.Results. In patients with idiopathic atrial fibrillation, relief of atrial fibrillation with sinus rhythm preservation until the end of surgery was more often observed than in patients with ischemic heart disease (22% vs. 10,6%, р = 0,021). In patients with ischemic heart disease, typical atrial flutter was much more common and there was a need to perform radiofrequency ablation of the cavothricuspid isthmus in addition to isolation of the pulmonary veins (47,9% vs. 18,8% 1 Group 1, р = 0,005, and 24,7% in Group 2, р = 0,01).Conclusions. The concomitant pathology of the cardiovascular system in patients affects the dynamics of the atrial rhythm during catheter treatment of atrial fibrillation and may take into account the definition of intraoperative tactics.

Identification and validation of potential biomarkers for atrial fibrillation based on integrated bioinformatics analysis.

Background: Globally, the most common form of arrhythmias is atrial fibrillation (AF), which causes severe morbidity, mortality, and socioeconomic burden. The application of machine learning algorithms in combination with weighted gene co-expression network analysis (WGCNA) can be used to screen genes, therefore, we aimed to screen for potential biomarkers associated with AF development using this integrated bioinformatics approach. Methods: On the basis of the AF endocardium gene expression profiles GSE79768 and GSE115574 from the Gene Expression Omnibus database, differentially expressed genes (DEGs) between AF and sinus rhythm samples were identified. DEGs enrichment analysis and transcription factor screening were then performed. Hub genes for AF were screened using WGCNA and machine learning algorithms, and the diagnostic accuracy was assessed by the receiver operating characteristic (ROC) curves. GSE41177 was used as the validation set for verification. Subsequently, we identified the specific signaling pathways in which the key biomarkers were involved, using gene set enrichment analysis and reverse prediction of mRNA-miRNA interaction pairs. Finally, we explored the associations between the hub genes and immune microenvironment and immune regulation. Results: Fifty-seven DEGs were identified, and the two hub genes, hypoxia inducible factor 1 subunit alpha inhibitor (HIF1AN) and mitochondrial inner membrane protein MPV17 (MPV17), were screened using WGCNA combined with machine learning algorithms. The areas under the receiver operating characteristic curves for MPV17 and HIF1AN validated that two genes predicted AF development, and the differential expression of the hub genes was verified in the external validation dataset. Enrichment analysis showed that MPV17 and HIF1AN affect mitochondrial dysfunction, oxidative stress, gap junctions, and other signaling pathway functions. Immune cell infiltration and immunomodulatory correlation analyses showed that MPV17 and HIF1AN are strongly correlated with the content of immune cells and significantly correlated with HLA expression. Conclusion: The identification of hub genes associated with AF using WGCNA combined with machine learning algorithms and their correlation with immune cells and immune gene expression can elucidate the molecular mechanisms underlying AF occurrence. This may further identify more accurate and effective biomarkers and therapeutic targets for the diagnosis and treatment of AF.

Co-expression and interaction network analysis identifies neutrophil-related genes as the core mediator of atrial fibrillation.

Atrial fibrillation (AF) is the most common cardiac arrhythmia and can cause serious complications. Several studies have shown that neutrophils may influence AF progression. However, the key genes related to neutrophils in AF have not been fully elucidated. Here, we downloaded microarray expression data of AF, and screened differentially expressed genes. Key immune cells in AF were identified by immune cell infiltration analysis. Weighted gene co-expression network analysis (WGCNA) and protein-protein interaction (PPI) analysis were used to construct gene co-expression modules and identify hub genes. The association between key genes and neutrophils was then verified. Our results showed that 303 differentially expressed genes (DEGs) were screened in AF and sinus rhythm (SR), of which 194 were up-regulated and 109 were down-regulated. DEGs were mainly enriched in functions and pathways of neutrophil activation and biological functions of neutrophil activation-mediated immune response. Immune infiltration analysis revealed elevated levels of neutrophil infiltration in AF. WGCNA analysis revealed that the modules in dark red were associated with neutrophils. PPI analysis of these modules yielded 10 hub genes. S100A12, FCGR3B and S100A8 are 3 potential key genes related to neutrophils in AF, which are significantly positively correlated with neutrophils. These genes deserve further investigation and may be potential therapeutic targets for AF.

Exercise echocardiography to assess left atrial function in patients with symptomatic AF

BackgroundLeft atrial (LA) function contributes to the augmentation of cardiac output during exercise. However, LA response to exercise in patients with atrial fibrillation (AF) is unknown. We explored the LA mechanical response to exercise and the association between LA dysfunction and exercise intolerance. MethodsWe recruited consecutive patients with symptomatic AF and preserved left ventricular ejection fraction (LVEF). Participants underwent exercise echocardiography and cardiopulmonary exercise testing (CPET). Two-dimensional and speckle-tracking echocardiography were performed to assess LA function at rest and during exercise. Participants were grouped according to presenting rhythm (AF vs sinus rhythm). The relationship between LA function and cardiorespiratory fitness in patients maintaining SR was assessed using linear regression. ResultsOf 177 consecutive symptomatic AF patients awaiting AF ablation, 105 met inclusion criteria; 31 (29.5 %) presented in AF whilst 74 (70.5 %) presented in SR. Patients in SR augmented LA function from rest to exercise, increasing LA emptying fraction (LAEF) and LA reservoir strain. In contrast, patients in AF demonstrated reduced LAEF and reservoir strain at rest, with failure to augment either parameter during exercise. This was associated with reduced VO2Peak compared to those in SR (18.4 ± 5.6 vs 22.5 ± 7.7 ml/kg/min, p = 0.003). In patients maintaining SR, LAEF and reservoir strain at rest and during exercise were associated with VO2Peak, independent of LV function. ConclusionThe maintenance of SR in patients with AF is associated with greater LA reservoir function at rest and greater augmentation with exercise compared to patients in AF. In patients in SR, reduced LA function is associated with reduced exercise tolerance, independent of LV function.

'Trapped re-entry' as source of acute focal atrial arrhythmias.

Diseased atria are characterized by functional and structural heterogeneities, adding to abnormal impulse generation and propagation. These heterogeneities are thought to lie at the origin of fractionated electrograms recorded during sinus rhythm (SR) in atrial fibrillation (AF) patients and are assumed to be involved in the onset and perpetuation (e.g. by re-entry) of this disorder. The underlying mechanisms, however, remain incompletely understood. Here, we tested whether regions of dense fibrosis could create an electrically isolated conduction pathway (EICP) in which re-entry could be established via ectopy and local block to become 'trapped'. We also investigated whether this could generate local fractionated electrograms and whether the re-entrant wave could 'escape' and cause a global tachyarrhythmia due to dynamic changes at a connecting isthmus. To precisely control and explore the geometrical properties of EICPs, we used light-gated depolarizing ion channels and patterned illumination for creating specific non-conducting regions in silico and in vitro. Insight from these studies was used for complementary investigations in virtual human atria with localized fibrosis. We demonstrated that a re-entrant tachyarrhythmia can exist locally within an EICP with SR prevailing in the surrounding tissue and identified conditions under which re-entry could escape from the EICP, thereby converting a local latent arrhythmic source into an active driver with global impact on the heart. In a realistic three-dimensional model of human atria, unipolar epicardial pseudo-electrograms showed fractionation at the site of 'trapped re-entry' in coexistence with regular SR electrograms elsewhere in the atria. Upon escape of the re-entrant wave, acute arrhythmia onset was observed. Trapped re-entry as a latent source of arrhythmogenesis can explain the sudden onset of focal arrhythmias, which are able to transgress into AF. Our study might help to improve the effectiveness of ablation of aberrant cardiac electrical signals in clinical practice.

Morphometrical features of left atrial appendage in the atrial fibrillation patients subjected to left atrial appendage closure.

This study aimed to evaluate the morphometrical features of left atrial appendage (LAA) in patients with atrial fibrillation, subjected to LAA percutaneous closure (LARIAT) for stroke prevention. Computed tomography (CT) scans of 51 patients with atrial fibrillation subjected to LARIAT procedure were comparatively evaluated with 50 patients with sinus rhythm (control group). Three-dimensional reconstructions were created using volume-rendering for evaluation. No differences were found in LAA types of distribution (cauliflower: 25.5 vs. 34.0%, chicken wing: 45.1 vs. 46.0%, arrowhead: 29.4 vs. 20.0%, all p > 0.05) between groups. However, the study group was characterized by LAAs with a lower number of lobes. The LAA orifice anteroposterior and transverse diameters (19.3 ± 4.12 vs. 17.2 ± 4.0 mm, p = 0.01 and 25.1 ± 5.1 vs. 20.5 ± ± 4.4 mm, p = 0.001), orifice area (387.2 ± 133.9 vs. 327.1 ± 128.3 mm2, p = 0.02) and orifice perimeter (70.2 ± 12.5 vs. 61.2 ± 11.6 mm, p = 0.04) was significantly larger in atrial fibrillation patients. More oval LAA orifices was found in atrial fibrillation group (94.0 vs. 70.4%, p = 0.001). No statistically significant differences were found in LAA body length (47.4 ± 15.4 vs. 43.7 ± 10.9 mm, p = 0.17), body width (24.7 ± 5.6 vs. 24.4 ± 5.8 mm, p = 0.81), and chamber depth (17.7 ± 3.5 vs. 16.5 ± 3.8 mm, p = 0.11). Calculated LAA ejection fraction was significantly lower in study group compared to healthy patients (16.4 ± 14.9 vs. 48.2 ± 12.9%, p = 0.001). Important morphometrical differences in LAA orifice have been found, which was significantly larger and more oval in patients with atrial fibrillation compared to healthy controls. Although no difference in LAA body type and size was observed; the LAA ejection fraction was significantly lower in atrial fibrillation rhythm patients.

Usefulness of risk scores and predictors of atrial fibrillation recurrence after elective electrical cardioversion.

Electrical cardioversion (ECV) is a frequently used procedure for restoring sinus rhythm in atrial fibrillation (AF); however, the rate of recurrence is high. The identification of patients at high risk of recurrence could influence the decision-making process. The present study evaluates the predictive value of risk scores in atrial fibrillation recurrence after elective electrical cardioversion. Unicentric, observational, and prospective study of adult patients who have undergone an elective ECV as rhythm control strategy between July 2017 and September 2022. From the 283 analyzed patients (mean age 63.95 ± 10.76212, 74.9% male); 99 had paroxysmal AF (35%) and 159 (59%) presented AF recurrence during a follow-up of 6 months. In patients with post-ECV AF recurrence, the period of time from diagnosis until the performance of the procedure was longer (393 ± 891 vs. 195 ± 527, p = .02). No paroxysmal AF (71.3% vs. 57.8%, p = .02) and LA dilatation with >40 mL/m2 (35.9% vs. 23.3%, p = .02) volumes were more frequent within these patients. AF recurrence was more frequent in patients who had previous ECV (HR = 1.32; 95% CI: 1.12-2.35; p = .01) and more than 1 shock to recover sinus rhythm (HR = 1.62; 95% CI: 1.07-1.63; p = .01). The SLAC, ALARMEc, ATLAS, and CAAP-AF scores were statistically significant, although with a moderate predictive capacity for post-ECV recurrence. Risk scores analyzed showed a modest value predicting AF recurrence after ECV. Previous ECV, and greater difficulty in restoring SR were independent predictors of recurrence.

Relationship between pre-procedural non-ischemic ST-segment depression and the clinical outcomes after catheter ablation in persistent atrial fibrillation patients

Abstract Background ST-segment depression suggests the presence of coronary artery disease (CAD) during sinus rhythm, but the clinical significance, including the outcomes after catheter ablation (CA), in atrial fibrillation (AF) patients remains unknown. Purpose The aim of this study was to investigate the relationship between non-ischemic ST-segment depression during AF rhythm before CA and late arrhythmia recurrence in persistent AF (PerAF) patients. Methods The present study included PerAF patients from the Osaka Rosai Atrial Fibrillation ablation (ORAF) registry who underwent an initial ablation and had no history of CAD. We assigned the patients based on the presence of ST-segment depression before CA and evaluated the impact of relevant factors on ST-segment depression and the relationship between ST-segment depression, including leads locations (anterior leads, inferior leads, and lateral leads) or depression type (upsloping, horizontal and downsloping) or the degree of ST-segment depression and late recurrence of AF (LRAF). Results This study population included a total of 551 patients of which 189 had ST-segment depression. The median follow-up duration was 397 days and LRAF occurred in 195 patients. By multiple regression analysis, diabetes mellitus, hemoglobin, brain natriuretic peptide, left ventricular ejection fraction and left atrial diameter were significant determinants of ST-segment depression before CA. Kaplan-Meier analysis demonstrated that the patients with ST-segment depression had a significantly greater risk of LRAF than those without (p&amp;lt;0.001). Multivariate Cox proportional hazards analysis showed ST-segment depression was independently and significantly associated with a higher risk of LRAF (p&amp;lt;0.001). The patients with ST-segment depression≥0.15mV had a significantly higher risk of LRAF than those with ST-segment depression≥0.15mV (p&amp;lt;0.001). No significant differences among the ST-segment depression leads locations and ST-segment depression type were observed. Conclusion Non-ischemic ST-segment depression during AF rhythm was significantly associated with LRAF post CA in PerAF patients.

The impact of sick sinus syndrome on flow velocity of the left atrial appendage in patients with atrial fibrillation

Abstract Background Sick sinus syndrome (SSS) itself has been suspected as one of potential embolic stroke sources, however, the mechanism remains unclear. Reduced flow velocity of left atrial appendage (LAAFV) plays a major role in thrombus formation in patients with atrial fibrillation (AF). We evaluated the contribution of SSS to LAAFV in patients with AF. Methods We studied 153 consecutive patients (age 69±10, 100 males, 79 paroxysmal AF, CHADS2 score 1.6±1.2) who underwent catheter ablation (CA) for AF at our hospital and our college of medicine. All patients enrolled in this study underwent transesophageal echocardiography (TEE) and transthoracic echocardiography prior to CA. LA global mean voltage and LA activation time were also measured using High-density LA mapping during CA. Clinical characteristics and laboratory data was obtained before CA for AF. SSS was defined as sinus arrest with 3 seconds or more by Holter ECG, or pacemaker implantation due to SSS. Results Reduced LAAFV was associated with old age (R²=0.0783, P=0.0005), female (R²=0.0260, P=0.0285), non-paroxysmal AF (R²=0.1403, P&amp;lt;0.0001), hypertension (R²=0.0226, P=0.0338), history of congestive heart failure (R²=0.0890, P=0.0007), high CHADS2 score (R²=0.1248, P&amp;lt;0.0001), high level of BNP (R²=0.2054, P&amp;lt;0.0001), AF rhythm during TEE (R²=0.1577, P&amp;lt;0.0001), low LV ejection fraction (R²=0.0255, P=0.0488), large LA diameter (R²=0.1544, P&amp;lt;0.0001), high E wave (R²=0.1168, P&amp;lt;0.0001), low LA global mean voltage (R²=0.1775, P&amp;lt;0.0001), long LA activation time (R²=0.1383, P&amp;lt;0.0001) and SSS (n=29, R²=0.0957, P=0.0002). On multiple linear regression analysis, SSS, AF rhythm during TEE, BNP, female was independently related to reduced LAAFV (Table). Conclusion SSS itself might be related to reduced LAAFV in patients with AF.Table

Artificial intelligence-enabled electrocardiogram in the detection of patients at risk of atrial functional mitral regurgitation

Abstract Background Atrial functional mitral regurgitation (AFMR) is an increasingly recognized cause of functional MR thought to result from left atrial enlargement and myopathy in the setting of preserved left ventricular geometry and function. AFMR mostly occurs in patients with atrial fibrillation (AF) and/or heart failure with preserved ejection fraction. Purpose We investigated whether the use of an artificial intelligence-based electrocardiogram (AI-ECG) can identify patients with new-onset AF and sinus rhythm (SR) who are at highest risk of developing AFMR. Methods Adults with a new diagnosis of AF between 2010 and 2021 who had a transthoracic echocardiogram (TTE) within 1 month after AF diagnosis were identified. Similarly, adults in SR who never had AF diagnosis and had a TTE during the same period were identified. Exclusion criteria from both groups included &amp;gt;mild MR at baseline, primary mitral valve disease, cardiomyopathy, ≥moderate aortic valve disease, current or previous low ejection fraction, enlarged left ventricle, cardiac devices, previous cardiac surgeries, and the absence of follow-up TTE ≥6 months from baseline. Only patients who had ECG within 10 days of the TTE were included. When multiple ECGs were available, the closest was considered. A previously trained AI-ECG algorithm to detect the probability of AF was utilized. Incident AFMR was defined as &amp;gt;mild functional MR in the absence of &amp;gt;mild left ventricle enlargement or dysfunction. Diastolic dysfunction was defined according to ASE/EACVI guidelines. Results Overall, 1,570 patients with new-onset AF (median age 67 years; 34% females) and 16,802 patients in SR (median age 59 years; 46% females) were included. The median AI ECG probability for AF was 43% (IQR 26%-59%) in the new-onset AF group and 2% (0.5%-7%) in the SR group, Figure 1. Incident AFMR occurred in 152 patients in the AF group over median 3.06 (IQR 1.5-5.2) years of follow-up and in 482 patients in the SR group over median 3.0 (1.5-5.6) years of follow-up. The probability of silent AF by the AI-ECG was associated with incident AFMR in the new-onset AF group [hazard ratio 1.19 (95% CI 1.11-1.28) per 10%, p &amp;lt;.001] and the SR group [hazard ratio 1.19 (95% CI 1.12-1.25) per 10%, p &amp;lt;.001]. The AI ECG-derived AF probability remained as an independent risk factor for AFMR in multivariable analysis in both AF and SR, Table 1. Conclusion The AI ECG for AF might be able to reflect the degree of left atrial myopathy and thus the risk of incident AFMR in patients with AF and SR.Distribution of AI ECG probability of AFMultivariable risk factors for AFMR

Snoring and lack of REM sleep is associated with same-day atrial arrhythmias in a cohort of patients with atrial fibrillation: initial results of TriggersAF

Abstract Introduction Sleep-disordered breathing (SDB) is a known risk factor for the development of atrial fibrillation (AF). Few studies analyse the temporal relation between snoring, sleep phases and atrial arrhythmia episodes. Purpose The TriggersAF trial (NCT05526170) investigates the temporal relation between atrial arrhythmias and potential triggers. In this preliminary analysis, the authors hypothesised that snoring and disturbance of sleep phases may be associated with same-day atrial arrhythmias. Methods In a single-centre prospective cohort study patients with previously diagnosed AF were recruited for home monitoring of 7 days. A single-lead continuous electrocardiogram (ECG) of the reference Holter monitor (Bittium, Kuopio, Finland) documented the cardiac rhythm. The recordings were manually annotated as: 1) AF, 2) atrial tachycardia or flutter (AT), 3) frequent premature atrial contractions (PAC), defined as bigeminy, trigeminy, quadrigeminy or couplets, and 4) no arrhythmia. Sleep disorders were evaluated using a validated sleep tracking mat (Withings Sleep Analyzer, Issy-les-Moulineaux, France) and described by the number of snoring episodes, durations of snoring, light, deep, and rapid-eye-movement (REM) phases. Heart echocardiography with strain imaging of left atrium (LA) was performed to further characterize the subjects. Results The study consisted of 49 patients, aged 55.8±11.7 years, 67.3% male. All patients were with previously diagnosed non-permanent AF and sinus rhythm at the moment of inclusion. The monitoring duration yielded a total of 300 days. The occurrence of AF, AT and PAC was detected in 32/300, 108/300 and 85/300 of days, respectively. As revealed by the sleep analysis a greater number of snoring episodes was associated with the same-day episodes of AF when compared to patients with no AF (5.0 (2-10.2) vs. 2.0 (0-7), P=0.029, respectively). A longer snoring duration was associated with the same-day episodes of AF (36 (6-80) min vs. 12 (0-52) min, P=0.057). A shorter duration of the REM phase was associated with AT (63 (28-93) min vs. 79 (42-105) min, P=0.032) and PAC (60 (32-91) min vs. 79 (37-102) min, P= 0.058). No significant relations were observed between the durations of light or deep phases and any type of arrhythmias. A smaller mean conduit strain of LA was highly associated with AF (-7,5 (-12,5, -7,5)) compared to patients with no AF (-11,0 (-14,8, -8,5), P= 0.002). In the Fast-and-Frugal Decision Tree for the prediction of same-day AF, a model combining the mean conduit strain of less than -9, a body mass index of more than 27.8, and a snoring duration of more than 29 minutes yielded a sensitivity of 97%, a specificity of 59% and a balanced accuracy of 78%. Conclusions The higher frequency and duration of snoring, as well as reduced REM phase of sleep are linked to same-day atrial arrhythmias. Long-term SDB monitoring and LA strain imaging predict the episodes of AF with high accuracy.Number of snoring episodes vs. AFAF by LA strain, BMI and snoring

AF in the AFternoon: The circadian pattern of incident atrial fibrillation in a loop recorder population

Abstract Introduction Loop recorders have provided the opportunity to systematically screen individuals for arrhythmias, and in doing so provide new appreciated mechanistic insights to arrhythmia pathophysiology. Atrial fibrillation (AF) is a complex arrhythmia with a multitude of precipitants and substrates. Previous studies looking at the circadian rhythm of AF, have required patient symptoms to define onset. All studies on the circadian rhythm of AF suggest that AF does not occur randomly. It has been suggested that the circadian variation in autonomic function may provide an underlying substrate for AF initiation. This is the largest study to utilise loop recorder detected AF to explore the circadian pattern of AF. Purpose We sought to ascertain how the detection of incident AF varied throughout the day, in patients monitored with a loop recorder Methods This was a single-centre retrospective observational study. Consecutive adult patients referred for ILR implantation between March 2009 and November 2019, without prevalent AF or atrial flutter, were included. Demographic and anthropometric data was identified from the individuals medical notes. The time of incident AF episodes was identified from loop recorder reports. Results A total of 1168 AF episodes of any duration were identified by the ILR, of which onset time was available for 1118 episodes. Onset of AF episodes in our data for the entire population demonstrated a monophasic distribution (figure 1a). The OR for developing AF between 13.00-14.59 compared to 03.00-04.59 was 4.89 (95% CI 3.47-6.90). Amongst the ESUS population time of onset distribution showed multiple daytime peaks (figure 1b). The OR for developing AF between 10.00-11.59 compared to 03.00-04.59 was 4.39 (95% CI 2.68-7.20). Amongst the non- ESUS population time of onset distribution (figure 1c) shows a monophasic pattern with the peak at time blocks 12.00-14.59. The OR for developing AF between 13.00-14.59 compared to 02.00-03.59 was 6.75 (95% CI 4.17-10.93). Conclusion(s) Our study demonstrated that there is a diurnal variation for incident AF detection using a loop recorder. There is a general propensity for episodes to occur in the afternoon, with a nadir at night. This is in contrast to previous reports which have suggested that the nocturnal and morning peaks are more apparent. Moreover, different cohorts appear to show different temporal patterns, with ESUS patients having multiple time peaks, whereas the non-stroke cohort had a solitary peak period. Understanding the diurnal variation of AF may help to shed more light on the complex pathogenesis of AF, and whether different AF phenotypes are associated with stroke risk. Moreover, the finding of a day-time propensity for AF, adds weight to the utilisation of consumer facing non-invasive monitoring tools during the day for AF identification in high-risk populations.

Association between left atrial strain and peri-operative stroke in catheter ablation for atrial fibrillation

Abstract Background It has been reported that left atrial (LA) phasic function, evaluated by LA strain, is associated with cardiogenic stroke in patients with atrial fibrillation (AF). There are no well-established echocardiographic findings to predict peri-operative stroke in AF ablation. Purpose The aim is to evaluate between LA strain and peri-operative stroke in AF ablation. Methods This study included 103 consecutive AF patients (90 paroxysmal and 13 non-paroxysmal AF cases) who underwent initial cryo-ablation without interruption of peri-operative anticoagulation from January 2019 to August 2022. Pre-operative echocardiography was used to measure the LA strain items: LA reservoir strain, contractile strain, and conduit strain in sinus rhythm. Twenty-three patients were excluded due to AF rhythm and atrial septal defect. Peri-operative stroke was detected by using magnetic resonance imaging on the day after ablation. Results Peri-operative stroke occurred in 9 patients (11.3%), and there was no symptomatic stroke. In univariate analysis, age (69.6 ± 4.8 years vs. 64.2 ± 10.9 years, p&amp;lt;0.05) and log brain natriuretic peptide (1.61 ± 0.26 vs. 1.32 ± 0.42 p&amp;lt;0.05) were significantly higher in the stroke group. On the other hand, LA reservoir strain (20.9 ± 5.6% vs. 29.8 ± 8.3%, p&amp;lt;0.01) and LA conduit strain (10.9 ± 2.3% vs. 15.9 ± 7.0%, p&amp;lt;0.01) in the stroke group was significantly lower compared with the non-stroke group. There were no significant differences in the rate of intra-operative electrical cardioversion and other clinical parameters between both groups. Receiver operating characteristic curve analysis revealed that LA reservoir strain cut-off value of 22.7% provided a c-statistic of 0.82 for predicting peri-operative stroke in AF ablation. Conclusions LA reservoir strain is closely associated with peri-operative stroke in AF ablation.ROC curve analysis

Abstract 14165: Left Atrial Appendage Emptying Velocity as a Predictor of Energy Required for Successful DC Cardioversion in Patients With Atrial Fibrillation

Background: Atrial fibrillation (AF) is a prevalent cardiovascular disease in the elderly population. Restoring sinus rhythm in AF often involves antiarrhythmic drugs, direct current (DC) cardioversion, and ablation. The predictive value of left atrial appendage (LAA) emptying velocity in determining the energy required for successful DC cardioversion remains uncertain. Aim: To study the association between LAA emptying velocity and the amount of energy required for cardioversion in patients with AF undergoing DC cardioversion. Methods: A total of 79 consecutive AF patients were enrolled in the study. Transesophageal echocardiography was performed to exclude the presence of clot formation, after which patients underwent DC cardioversion using escalating biphasic energy levels of 100 joules, 200 joules, and 360 joules to restore sinus rhythm. Patients were stratified into two groups based on LAA emptying velocity: the low-velocity group (≤30 cm/sec) and the high-velocity group (&gt;30 cm/sec). Clinical characteristics were compared between the groups. Results: Of the 79 patients, 49 had a low LAA emptying velocity (LAAEV). The low-velocity group was older, with a mean age of 75 years compared to 70 years in the high-velocity group. The severity of mitral regurgitation was similar between the two groups. Patients with reduced LAA emptying velocity required significantly higher joules for successful cardioversion compared to the high-velocity group (192 joules vs. 155 joules, p-value = 0.02). Sleep apnea was more prevalent in the high-velocity group. The utilization of antiarrhythmic medications did not differ significantly between the groups (55% vs. 63%, p-value = 0.25). Conclusions: The study showed AF patients with low LAA emptying velocity require higher energy levels for successful cardioversion, suggesting that LAA emptying velocity may serve as a predictor of energy requirement in DC cardioversion for restoring sinus rhythm in AF patients.

Abstract 18213: Predictors of Left Atrial Appendage Occlusion Device-Related Thrombus

Background: Left atrial appendage (LAA) occlusion (LAAO) is preformed to prevent LAA thrombus and cardioembolic stroke in patients with atrial fibrillation (AF). There is however up to 4% risk of device related thrombus (DRT) on the left atrial (LA) side of LAAO device that is a cause for stroke. Predicting which patients are at high risk of DRT would enable more aggressive anticoagulation strategies and closer surveillance to prevent stroke post LAAO. Objective: To develop a risk score to predict DRT. Methods: From the LAAO registry at University of Kansas Medical Center we identified 26 patients with DRT. We chose 3 controls per case at random from other LAAO recipients without DRT. Predictor variables were obtained from transesophageal echocardiogram (TEE) reports and images, transthoracic echocardiogram reports and detailed clinical chart review. LAAO device depth was measured from the center of the device to the peak of the left atrial ridge in 45° TEE view. Results: We analyzed 26 DRT patients (age 77.7±9.7 yr, 34.6% female) and 78 controls. Univariate predictors of DRT included history of venous thromboembolism (VTE, 23.1% vs 5.1%, P=0.01), presence of spontaneous LA echocontrast (SEC) on TEE (26.9% vs 7.7%, p=0.02), implant depth &gt;2 cm (34.6% vs 12.8%, p=0.02) and rhythm at implant being AF (50.0 % vs 11.5%, p=0.0001). Using a multivariate model with these variables we devised a risk score with 1 point each factor except 2 points for AF rhythm. A total score of ≥3 had odds ratio 13.6 (95% CI 3.8-48.4, p&lt;0.0001) of DRT (see Tables). Discussion: We present a DRT risk score comprising history of VTE, LA SEC, implant depth &gt;2 cm (1 point each) and AF rhythm (2 points). Score of ≥3 identified patients at high risk of DRT. This score needs to be validated in an independent dataset.

Abstract 16885: Progression of Aortic Valve Stenosis in Atrial Fibrillation versus Sinus Rhythm: Implications for Clinical Practice and Severe Aortic Stenosis Diagnosis

Introduction: Rate of aortic stenosis (AS) progression in patients with concurrent atrial fibrillation (AF) has not been previously described. Objectives: To describe changes over time in aortic valve area (AVA) and associated hemodynamics during AS progression in patients in AF versus sinus rhythm (SR). Methods: Patients with AVA ≤ 1 cm 2 and preserved left ventricular ejection fraction ≥50% were identified from the Mayo Clinic Echocardiographic Laboratory Database. Serial echocardiograms prior to the development of AVA ≤ 1 cm 2 (Time 0) were examined. Inverse probability weighting was used for statistical analysis. Results: A total of 166 patients were included (SR=79 and AF=87), mean age 78.1 ± 7.8 years, females 31%. The rates of AVA reduction (-0.14±0.01 vs -0.12±0.01 cm2/year, p=0.31) and increase in trans-aortic peak velocity (+0.23 ± 0.02 vs +0.22 ± 0.02 m/sec, p=0.55) and mean gradient (MG) (3.9 ± 0.3 vs 3.8 ± 0.4 mmHg, p=0.83) did not differ between AF and SR (Figure 1). However, AF was associated with systematically lower forward stroke volume index (SVi), peak velocity and MG for the same AVA compared to SR (p&lt;0.04 for all) throughout AS progression. When AVA reached 1 cm 2 , SVi (38.8±6.6 vs 45.7 ±8.9, p=0.02), peak velocity (3.9 ± 0.6 vs 4.1 ± 0.6 m/sec, p=0.04) and MG (36.6±10.9 vs 41±12.8 mmHg, p=0.03) were lower in AF compared to SR. Conclusions: The rate of AS progression was not different in AF versus SR. However, forward flow was systematically lower in AF resulting in discordant AS during AS progression and when AVA reached 1 cm 2 . Doppler velocity and MG criteria for severe AS appear to be lower in AF versus SR which has implications for timely diagnosis of severe AS and patient management.

Abstract 17275: Clinical Outcomes Following Maze and Left Atrial Appendage Occlusion Procedures for Patients With Atrial Fibrillation Undergoing Mitral Valve Surgeries: Insights From the National Readmission Database

Background: Maze procedure and left atrial appendage occlusion (LAAO) are often done as adjunctive procedures during mitral valve surgery in patients with atrial fibrillation (AF). We examined the effect of the Maze procedure and LAAO on AF-related clinical outcomes. Methods: We identified patients with AF from the Nationwide Readmission Database who underwent mitral valve surgery in the years 2016-2019 using ICD 10 codes. Patients were grouped by procedure type (Maze+/LAAO+, Maze+/LAAO-, Maze-/LAAO+, Maze-/LAAO- (control)). Outcomes were in-hospital and 180-day readmission rate for stroke and mortality, and 180-day AF/atrial flutter readmission. Multivariate regression analysis was conducted adjusting for demographics, hospital characteristics, comorbidities, and cardiac surgery type. Results: Of 14,979 patients with AF who underwent mitral valve surgery, adjunctive procedures were performed as follows: 2427 Maze+/LAAO+, 997 Maze+/LAAO-, 4052 Maze-/LAAO+, and 7503 Maze-/LAAO-. Stroke during the index admission and within 180 days occurred less frequently in the adjunctive procedure groups than in control group (2.5%, 2.3%, 3.4%, and 4.9% respectively, P&lt;0.001). Similar results were observed for in-hospital and 180-day mortality (3.9%, 7.6%, 4.8%, and 6.8% respectively, P&lt;0.001). However, readmission within 180 days for AF/atrial flutter was higher in the adjunctive procedure groups than the control group (5.6% vs 4.2% vs 5.4% vs 3.8%, P&lt;0.001). On multivariate analysis, patients who had either Maze or LAAO procedures (Maze+/LAAO+, Maze+/LAAO-, Maze-/LAAO+) had a lower 180-day stroke risk when compared to the control group (hazard ratio (HR) 0.7, P=0.01; HR 0.66, P=0.55; and HR 0.79, P=0.01 respectively). Similarly, 180-day mortality was lower in patients who underwent LAAO compared to the control group (HR 0.71, P=0.002; HR 1.27, P=0.05; and HR 0.78, P=0.004 respectively). Conclusion: Patients with AF who underwent Maze and/or LAAO procedures during mitral valve surgery had lower 180-day stroke and mortality rates. There was a higher rate of readmission for AF/atrial flutter, which may be a short-term proarrhythmic effect of these procedures or may reflect differences in AF type and rhythm control goals in the control group.

Abstract 15926: Left Atrial Pressure and H 2 FPEF Score in Patients With Atrial Fibrillation Who Underwent Catheter Ablation

Introduction: Heart failure with preserved ejection fraction (HFpEF) is a common comorbidity in atrial fibrillation (AF) patients and contributes to AF progression and stroke risk. Hypothesis: We explore the hemodynamic effects of left atrial pressure (LAP), which was directly measured during AF catheter ablation (AFCA), on HFpEF based on the H 2 FPEF score. Methods: We included 1,426 patients (73.3% male, median age, 61.0 [54.0-68.0] years; 45.7% persistent AF) who underwent AFCA, LAP measurements at both AF and sinus rhythm (SR), echocardiogram, and H 2 FPEF score, and excluded the patients with EF &lt;50%. We divided patients into low-risk (&lt; 6 points) and high-risk ( ≥ 6 points) HFpEF groups and measured LAP-mean depending on heart rates 90, 100, 110, and 120 bpm during right atrial pacing (Pace-HR) and isoproterenol (ISO-HR) infusion in all patients. Results: The LAP-mean was sequentially and significantly higher according to the H 2 FPEF score (p&lt;0.001) and had an independent association with the high-risk HFpEF group (OR 1.37 per 10mmHg increase [1.13-1.67], p=0.001). LAP-mean increased significantly with increasing Pace-HR (90-120 bpm, 10.4 to 11.6 mmHg, p&lt;0.001) but decreased with ISO-HR (90-120 bpm, 10.2 to 8.1 mmHg, p&lt;0.001). In patients with paroxysmal AF, LAP-mean[AF] was significantly higher than LAP-mean[SR] (p&lt;0.001), but not in those with non-paroxysmal AF (p=0.557). In patients with paroxysmal AF, ΔLAP-mean[Pace-HR, 120-90bpm] was significantly higher than that of non-paroxysmal AF (p&lt;0.001). Conclusions: LAP is independently associated with H 2 FPEF score and has inverse rate-dependent response depending on pacing or ISO infusion. Higher increase of LAP during AF or higher Pace-HR contributes to more severe symptoms in patients with paroxysmal AF than in non-paroxysmal AF.