Occurrence Of Atrial Fibrillation Research Articles

Hemorrhagic Transformation Incidence in Ischemic Stroke with Hyperthyroidism Rick Factor Accompanied by Atrial Fibrillation

Hemorrhagic transformation (HT) is one of the most common life-threatening complications of ischemic stroke. It occurs when peripheral blood extravasates through the damaged blood-brain barrier (BBB) ​​into the brain parenchyma after ischemic stroke. Hyperthyroidism, the most common endocrine disorder, occurs in 0.5−2% of the general population. Hyperthyroidism is known to trigger several cardiovascular system effects, one of which is the occurrence of atrial fibrillation (AF). There is a study that says that the incidence of HT in ischemic stroke patients with AF increases by 22.6%. A 48-year-old man with complaints of weakness of the left arm and leg, dysarthria and dysphagia with onset 2 hours before coming to the emergency department. Radiological examination showed bleeding with surrounding infarction and hyperthyroidism with AF was found. Hyperthyroidism is associated with AF which will increase the incidence of extensive ischemic stroke and the risk of experiencing HT due to damage to the BBB. Keywords: Hemorrhagic transformation (HT); ischemic stroke; hyperthyroidism; atrial fibrillation (AF); risk factors

The association between adipokines dysregulation and the occurrence of atrial fibrillation and obese patients, is it relevant?

Atrial fibrillation (AF) is the most common arrhythmia, affecting approximately 33.5 millions of people worldwide. Unfortunately, the prevalence of this arrhythmia will increase within the following two decades, resulting in a higher mortality rate and a higher economic burden for public health services. Obesity, specifically central obesity, plays an essential role in developing AF by increasing pericardial fat and epicardial adipose tissue thickness, generating a chronic inflammation state where dysregulation of the serum concentration of several proinflammatory proteins occurs and indirectly promotes AF. Therefore, recent research has focused on analyzing the circulating concentration of different molecules, including pro and anti-inflammatory adipokines, and their association with AF. Herein, we review several studies addressing the association of adipokines with the onset or recurrence of AF to establish such association as a potential biomarker for the prevention or adequate treatment of this arrhythmia. We concluded that the insight into this topic is very controversial and needs further research.

ECG-based machine learning model for AF identification in patients with first ischemic stroke.

The recurrence rate of strokes associated with atrial fibrillation (AF) can be substantially reduced through the administration of oral anticoagulants. However, previous studies have not demonstrated a clear benefit from the universal application of oral anticoagulants in patients with embolic stroke of undetermined source. Timely detection of AF remains a challenge in patients with stroke. This study aims to develop a convolutional neural network (CNN) model to accurately identify patients with AF using a 12-lead sinus-rhythm electrocardiogram (ECG) recorded around the time of the first ischemic stroke. Additionally, this study also evaluates the model's ability to predict future occurrence of AF. A CNN model was trained with ECG data from patients at Taipei Veterans General Hospital. External validation was performed on ischemic stroke patients from National Taiwan University Hospital. The model's performance was assessed for detecting AF at the stroke event and predicting future AF occurrences. The model demonstrated an area under curve (AUC) of 0.91 for internal validation and 0.69 for external validation in identifying AF at the stroke event, with sensitivity and negative predictive value both achieving 97%. Kaplan-Meier survival analysis of patients without a prior diagnosis of AF revealed a significant increase in future AF incidence among the high-risk group identified by the model (adjusted hazard ratio: 4.06; 95% confidence interval: 2.74-6.00). The CNN model effectively identifies AF in stroke patients using 12-lead ECGs and predicts future AF events, facilitating early anticoagulation therapy and potentially reducing recurrent stroke risk. Further prospective studies are warranted to confirm these findings.

QTc interval prolongation and risk of atrial fibrillation recurrence: a meta-analysis and observational cohort study

IntroductionCorrected QT interval (QTc) is a ventricular repolarization marker on electrocardiography. Previous studies evaluated its value in predicting atrial fibrillation (AF) occurrence. However, its predictive efficacy for AF recurrence remains controversial.MethodsWe searched PubMed and Google databases for studies before January 2024 evaluating the association between QTc interval and AF incidence. A meta-analysis of the eligible datasets was conducted using Bazett's formula, with subgroup analysis to explore the heterogeneity. Additionally, thirty-eight patients with AF who underwent radiofrequency catheter ablation were enrolled and followed-up for 3–36 months. Univariate and multivariate Cox models were used to calculate the hazard ratios (HRs) and determine the relationship between clinical factors and AF recurrence. Kaplan-Meier survival analysis and ROC curve were conducted to assess the impact and predictive efficacy of individual factors.ResultsEleven datasets from nine eligible studies were enrolled and meta-analysed. We found that patients with prolonged QTc interval was associated with a significantly higher AF incidence risk, and the risk increased with every 10-ms prolongation. However, this association was not significant in the AF recurrence subgroup. In our prospective cohort, the preoperative body mass index, QTc, left atrial diameter (LAD), and uric acid levels influenced AF recurrence. Multivariate Cox regression analysis identified LAD as an independent factor affecting AF recurrence in patients with a high predictive efficiency. Kaplan-Meier survival analysis showed that increased LAD (>4.5 cm) was associated with postoperative AF recurrence.DiscussionTherefore, LAD has better predictive power and can be an indicator for predicting postoperative AF recurrence.

β-Hydroxybutyrate and Citrate Synthase as Potential Diagnostic Biomarkers in Aging-Related Atrial Fibrillation.

The incidence of atrial fibrillation (AF) increases with age; however, the precise mechanisms by which aging elevates AF risk and the effective biomarkers for managing AF in elderly patients remain unclear. We analyzed plasma samples from 100 elderly AF patients, 100 young and 100 elderly patients without atrial fibrillation (NAF), along with left atrial tissues obtained from both AF and NAF patients following valve replacement. Our findings indicate reduced levels of β-OHB and citrate synthase (CS) activity in elderly AF patients compared to their NAF counterparts. Statistical analysis revealed a protective association between β-OHB and CS activity concerning the occurrence of elderly AF. Furthermore, atrial tissues from elderly AF patients exhibited mitochondrial dysfunction, structural remodeling, and low-voltage areas. These results suggest that dysregulation of β-OHB levels and CS activity may contribute to aging-related AF by affecting mitochondrial function and atrial remodeling, highlighting their potential as diagnostic biomarkers for this condition.

Predictors of New-Onset Atrial Fibrillation in Patients With Chronic Coronary Artery Disease After Coronary Artery Bypass Grafting: a Prospective, Observational, Single-Centre, Non-Randomized Study

To study the factors that influence the occurrence of postoperative atrial fibrillation (POAF) in patients with chronic ischemic heart disease (IHD) after coronary artery bypass grafting (CABG). This single-center prospective observational non-randomized study included 152 patients with chronic IHD. Mean age of patients was 64.4±5.9 years. All patients after CABG were divided into two groups based on the occurrence of atrial fibrillation (AF) in the early postoperative period: group 1, with POAF (n=43; 28.3%) and group 2, without POAF (n=109; 71.7%). The primary study endpoint was new-onset POAF in the early postoperative (hospital) period after CABG. The secondary study endpoint was in-hospital postoperative complications (non-fatal/fatal acute coronary syndrome (ACS), non-fatal/fatal stroke, major bleeding, death). Patients with POAF had significantly more pronounced structural and functional changes in the heart than patients with preserved sinus rhythm after CABG: larger left ventricular (LV) volume, greater LV myocardial mass, lower LV systolic function parameters and impaired diastolic function, and an enlarged left atrial (LA) cavity. Analysis of in-hospital complications did not show any differences between the groups associated with the development of POAF. The following risk factors for POAF were identified: age older than 65 years (p=0.022), body mass index ≥30.5 kg/m2 (p=0.020), epicardial adipose tissue thickness >10.5 mm (p=0.015), indexed LA volume >33 ml/m2 (p<0.001), LV myocardial mass index >115 g/m2 (p=0.042), left main coronary artery disease >50% (p=0.043), duration of cardiopulmonary bypass during CABG >60 min (p=0.019), blood potassium concentration in the early postoperative period after CABG (on the first day) <3.6 mmol/l (p<0.001), and pericardial effusion volume in the early postoperative period >88 ml (p<0.001). Determining the risk of developing POAF is important and necessary for the closest monitoring of a patient with chronic IHD in the postoperative period.

Changes of the Heart Rhythm in Imbalance of Thyroid Gland Hormones and its Morphology in Outbred Rats

To analyze the relationship between the occurrence of atrial fibrillation (AF) and thyroid dysfunction caused by low concentrations of free triiodothyronine (FT3), free triiodothyronine and free thyroxine (FT3 and FT4), and high concentrations of free thyroxine (FT4) with normal values of thyroid-stimulating hormone (TSH) in experiments on outbred rats. The pathogenesis of AF with low concentrations of FT3, FT3 and FT4, and a high concentration of FT4 was studied in an experiment on 146 outbred rats. In the experiment, hypothyroidism, euthyroidism, and thyrotoxicosis were modeled by changing the concentrations of thyroid hormones, and the effect of these conditions on ECG and the incidence of AF was evaluated. The types of the hypothalamic-pituitary-thyroid system response to the L-thyroxine administration in experimental hypothyroidism were identified. A relationship was determined between AF paroxysms and threshold values of thyroid hormones at low concentrations of FT3, FT3 and FT4, and a high concentration of FT4 with normal TSH values. It was shown that achieving the euthyroid status did not reduce the incidence of AF paroxysms by more than 70.0%. In AF with low FT3, low FT3 and FT4, and high FT4, the dose of L-thyroxine must be adjusted.

Incidence and outcomes of transient new-onset atrial fibrillation complicating acute coronary syndromes: results from a systematic review and meta-analysis

Abstract Background The overall risk of long-term adverse events of a transient episode of new-onset atrial fibrillation (AF) in patients with acute coronary syndrome (ACS) remains uncertain. This meta-analysis aimed to assess the prognostic impact of transient new-onset AF complicating ACS. Methods and results Cohort studies examining the risk of adverse events in patients with transient new-onset AF compared to those in sinus rhythm after ACS were identified through a comprehensive search of MEDLINE, Scopus, Cochrane, and Google Scholar Library. Studies reporting the incidence of ischaemic stroke events, recurrent AF, or all-cause mortality at the longest follow-up were included. Adjusted hazard ratios (aHRs) with 95% confidence intervals (CI) were synthesized using inverse variance-weighted random-effects meta-analysis. In the seven observational studies included, comprising 151 735 patients, 6 597 (4.3%) experienced transient new-onset AF, which was associated with an increased risk of ischaemic stroke, recurrent AF, or all-cause mortality (HR: 2.24, 95% CI: 1.75–2.85; P < 0.0001; I2 = 30.76%; seven studies). The results remained consistent across each individual endpoint, including ischaemic stroke (HR 2.38, 95% CI: 1.64–3.44; P < 0.01; I2 = 50.2%; five studies), recurrent AF (HR 4.68, 95% CI: 2.07–10.59; P = 0.0002; I2 = 50.2%; four studies), and all-cause mortality (HR 1.36, 95% CI: 1.08–1.71; P = 0.0089; I2 = 53.25%; four studies). Meta-regression analyses revealed a significant increase in these adverse events associated with ST-elevation myocardial infarction (P = 0.001), while there was a tendency for their decrease associated with oral anticoagulant prescription at discharge (P = 0.07). Conclusions The occurrence of transient new-onset AF is associated with an elevated long-term risk of stroke, recurrent AF, and all-cause mortality in patients with ACS. Consequently, these data urge randomized clinical trials to assess the best antithrombotic regimen while potentially helping the current treatment decision-making process for these patients.

Left atrial enlargement: a crucial indicator for identifying atrial fibrillation in patients with hypertension

Abstract Background Left atrial enlargement resulting from hypertension is closely linked to the development and persistence of atrial fibrillation (AF). The newly proposed staging recognizes AF as disease continuum, which makes us aware that AF prevention should focus on the Pre-AF stage, and atrial enlargement is one of the important manifestations in this stage. Previous scoring systems, such as CHA2DS2-VASc and C2HEST, along with the recently highlighted left atrial diameter (LAD), have been significant tools for predicting AF occurrence. However, a comprehensive assessment of their utility is currently lacking. Purpose This study aims to explore the role of left atrial size in identifying atrial fibrillation (AF) among hospitalized hypertensives, and to compare its recognition effectiveness with previous scoring systems. Methods We conducted a cross-sectional analysis within hospitalized hypertensives. The discovery, internal and external validation datasets were established. The XGBoost was employed to identify key variables related to AF occurrence, which were ranked based on their importance scores. To gauge the predictive prowess of LAD regarding AF occurrence, we plotted the receiver operating characteristic curve (ROC) and calculated the area under the curve (AUC). This enabled us to pinpoint the LAD cutoff value corresponding to the maximum Youden index, indicative of susceptibility to AF. Subsequently, Youden index determined the optimal cutoff value from the ROC curve. Delong’s test compared the identification abilities of different tools within the same dataset. Logistic regression analysis assessed the correlation between clinical variables and left atrial size. Results The XGBoost revealed 17 variables affecting AF occurrence in hypertensives, with LAD, age, and HF ranking among the top 3 (Figure 2a). LAD had a more pronounced impact on AF occurrence than other variables. LAD-based identification of AF in hypertensives had AUC of 0.827 (95%CI: 0.816-0.837), with an optimal cutoff of 38mm. Subgrouping the study population by LAD≥38mm, ROC curves showed AUCs of 0.757 (95%CI: 0.745-0.768) for the discovery set, 0.750 (95%CI: 0.731-0.768) for internal validation, and 0.759 (95%CI: 0.743-0.776) for external validation. LAD≥38mm had a more higher and stable AUC value for judging the AF occurrence than CHA2DS2-VASc and C2HEST scores (Figure 2b). Hypertensives with LAD≥38mm had a 9.72-fold higher AF risk than those with LAD<38mm. Conclusion LAD is a pivot determinant for AF occurrence. LAD≥38mm is a valuable identifier for high-risk hypertensives prone to AF.Figure 1.Center illustrationFigure 2.XGboost and Delong’s test of ROC

Left atrioventricular coupling index is an independent associate of new-onset AF and stroke in hypertrophic cardiomyopathy: a CMR study

Abstract Background Left atrial (LA) dysfunction is an important marker of disease progression in hypertrophic cardiomyopathy (HCM). LA volumes and functional parameters are associated with new-onset atrial fibrillation (AF) and its complications including stroke. The association between left atrioventricular coupling (LACI), a parameter reflecting the contribution of the left ventricular and LA remodeling to LA dysfunction, with the occurrence of new-onset AF and stroke has not been evaluated. Aim To investigate the association between LACI and the occurrence of new-onset AF or stroke in patients with HCM. Methods In patients with an established diagnosis of HCM and cardiac magnetic resonance (CMR) data, LACI was calculated as the ratio between the LA and the LV end-diastolic volumes. New-onset AF or occurrence of stroke comprised the primary combined endpoint. Cumulative event-free survival rates for the occurrence of the primary endpoint were estimated with the population divided according to a LACI cut-off value of 40%. The association between clinical and CMR variables and the primary endpoint was assessed with univariable and multivariable Cox proportional hazard regression models. Results Of 114 patients with HCM, (mean age 54±16 years, 33 (29%) female, LV ejection fraction 67.0±8.4%), 71 patients (49%) had a LACI > 40% (left atrioventricular uncoupling). During a median follow-up of 4.1 (1.8-6.4) years, 19 (16.7%) patients experienced new-onset AF or stroke. Patients with preserved left atrioventricular coupling (LACI ≤ 40%) had a lower cumulative rate of events compared to those with left atrioventricular uncoupling (log-rank p=0.031, Fig. 1). LACI was independently associated with new-onset AF or stroke after adjusting by the presence of late gadolinium enhancement (LGE) sex and age (HR=23.27, p=0.016). Conclusions In patients with HCM, the presence of left atrioventricular uncoupling is independently associated with the occurrence of new-onset AF or stroke.

Prognostic implications and alterations in left atrial deformation following transcatheter aortic valve implantation for severe aortic stenosis

Abstract Background Left atrial reservoir strain (LARS) as a single parameter estimate of left ventricular (LV) diastolic dysfunction (DD), may provide important prognostic insights into patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI). Purpose To evaluate the prognostic implications of pre- and post TAVI LARS-defined DD (LARS-DD) grade in patients undergoing TAVI for severe AS and its association with new-onset atrial fibrillation. Methods Pre-TAVI LARS-DD was evaluated by speckle-tracking echocardiography and was assigned as grade 0 to 1 (LARS ≥24%), grade 2 (LARS ≥19 to <24%) and grade 3 (LARS <19%). Patients were followed-up for the primary endpoint of all-cause mortality from the date of TAVI. For the secondary endpoint, patients with pre- and post-TAVI LARS measurements, no history of atrial fibrillation and with clinical/ECG follow-up following the post-TAVI follow-up echocardiogram were evaluated for the occurrence of new-onset atrial fibrillation. Results A total of 601 patients (median age 81 [76-85] years, 53% male) undergoing TAVI for severe AS were included. Overall, 169 patients (28%) were LARS-DD grade 0/1, 96 patients (16%) were LARS-DD grade 2 and 336 (56%) were LARS-DD grade 3. Over a median follow-up of 40 (IQR 26 to 58) months, a total of 258 (43%) patients died (Figure 1). In a comprehensive multivariable Cox regression model adjusted for age, sex, EuroSCORE II, New York Heart Association class III to IV symptoms, LV ejection fraction, atrial fibrillation, LA volume index and LV stroke volume index, LARS-DD grade was independently associated with all-cause mortality (adjusted HR 1.28 per one grade increase above LARS-DD grade 0/1, 95% CI 1.07 to 1.53, P=0.007). For the secondary endpoint of new-onset atrial fibrillation, a total of 285 patients were evaluated (Figure 2). On multivariable Fine and Gray regression analyses adjusting for age and LA volume index, post-TAVI LARS (SDHR 1.14 per 1% <20%, 95% CI 1.05 to 1.23, P=0.0009), rather than pre-TAVI LARS (SDHR 1.00 per 1% <20%, 95% CI 0.91 to 1.11, P=0.93) was associated with the occurrence of new-onset atrial fibrillation. Conclusions Increasing LARS-DD grade was independently associated with long-term post-TAVI survival in patients with severe AS and may enhance risk stratification. In addition, post-TAVI LARS, but not pre-TAVI LARS, was closely related to the occurrence of new-onset atrial fibrillation, likely better reflecting intrinsic LA dysfunction.Figure 1:All-Cause MortalityFigure 2:New-Onset Atrial Fibrillation

Circadian rhythm in atrial fibrillation detected by implantable loop recorder: a post-hoc analysis of a randomized clinical trial

Abstract Introduction Previous studies suggest the existence of circadian, weekly, and seasonal rhythms in the occurrence of atrial fibrillation (AF), which may be utilized to improve the yield of screening. The heterogeneity of AF natural history also necessitates better phenotyping to overcome the challenges of identifying candidates for screening and treatment. Purpose To explore the potential circadian rhythm in AF occurrence in persons without known arrhythmia but at high risk of AF and stroke. Methods Post-hoc analysis of the LOOP study (Atrial Fibrillation Detected by Continuous Electrocardiogram Monitoring Using Implantable Loop Recorder to Prevent Stroke in High-Risk Individuals), which randomized 6004 AF naïve participants (≥70 years old with additional stroke risk factors) 1:3 to receive implantable loop recorder screening or usual care. All loop recorder data was extracted to obtain the date and time of AF episode onset, AF duration, mean and max heart rate (HR) during AF, and symptom annotations. New-onset AF episodes lasting ≥6 minutes were adjudicated, and all subsequent episodes were included in the analysis. Results A total of 41,713 AF episodes (median duration 18 (8-64) minutes) were identified among 430 participants (Table 1). The median number of episodes for each participant with AF was 21 (4-82) and the median AF burden was 0.17% (0.04%-0.83%) of time from debut to end of monitoring. The most and least frequent days of AF onset were Sunday (15.3%) and Friday (13.6%), respectively, while AF occurred slightly more often during spring (26%) than in other seasons. The median time of onset was 09:57:15 AM (05:15:30 AM – 03:33:00 PM). The most frequent time of onset was at 09:00 AM (rounded to the nearest hour), which was two times more likely than at 09:00 PM, and 22% of all episodes occurred between 08:00 and 11:00 AM (Figure 1). A total of 25,329 (61%) episodes occurred between midnight and noon (AM). Nocturnal episodes, defined as episodes with onset between 10:00 PM and 07:00 AM, occurred in 368 (86%) AF participants and constituted a median of 40% of all episodes and 37% (14%-63%) of each participant’s episodes. The median duration of nocturnal episodes was 28 (10-104) minutes compared to 14 (8-44) minutes for daytime episodes. The averaged heart rate during AF was 81 (71-96) beats per minute (BPM), while 330 (77%) participants had AF episodes with heart rates equal to or above 100 BPM, and the duration of these episodes was 50 (15-201) minutes compared to 30 (21-85) minutes for slower episodes (below 100 BPM). Conclusion A circadian pattern was observed for screening-detected AF. AF onset occurred predominantly between 08:00 and 11:00 AM, representing more than one in five episodes. Nocturnal AF occurred in most participants with AF and accounted for almost half of all episodes, while these episodes also lasted longer than daytime episodes. This may warrant future studies investigating the timing of AF screening.

Polygenic risk score for prediction of atrial fibrillation according to presence of the hypertrophic cardiomyopathy

Abstract Background The significance of genetic predisposition in predicting atrial fibrillation (AF) is well recognized, yet its role in hypertrophic cardiomyopathy (HCM) patients remains less clear. Objective In this study, we aimed to elucidate the impact of genetic risk on the development of AF in both HCM and non-HCM patients. Methods This retrospective analysis examined 1,180 HCM patients (mean age 61.1±7.1, 63.0% male) and 476,238 non-HCM patients (mean age 57.0±8.1, 45.3% male) from the UK Biobank. Participants were stratified based on their validated polygenic risk score (PRS) for AF: the bottom 10% constituted the low genetic risk group, the top 10% comprised the high genetic risk group, and the remainder fell into the intermediate genetic risk group. We assessed the incidence of AF and major cardiovascular events and analyzed predictors, including genetic risk. Results Among HCM patients, no significant differences in baseline characteristics were observed based on genetic risk, except for the rate of CIED implantation (P=0.036). Conversely, among non-HCM patients, variations in age, gender, and comorbidities were noted according to genetic risk. The HCM patients were categorized into three groups based on risk, with respective AF incidence rates of 2.4, 3.6, and 5.4 events per 100 person-years, respectively. In non-HCM patients, the incidence of AF per 100 person-years was 0.2, 0.5, and 1.0, respectively. Genetic risk emerged as a significant predictor of AF in both HCM and non-HCM patients, although with a higher hazard ratio observed in non-HCM patient (HR, 2.51; 95% CI, 1.59–3.98 vs. HR, 4.77; 95% CI, 4.47–5.09) (P=0.003 for interaction). In non-HCM patients, predictors of AF included age, male sex, body mass index, smoking history, and a history of hypertension, diabetes, heart failure, stroke, and myocardial infarction, in addition to PRS. However, in HCM patients, only age, diabetes, and a history of stroke were identified as independent predictors of AF. Moreover, high genetic risk was significantly associated with the risk of major adverse cardiovascular events. Conclusions In conclusion, our study indicates associations between genetic predisposition and AF occurrence in both HCM and non-HCM patients.

Impact of changes in left heart geometry on predicting new-onset atrial fibrillation in patients with hypertension

Abstract Background Hypertension-induced left ventricular hypertrophy (LVH) increases end-diastolic LV pressure and contributes to left atrial enlargement (LAE), which are associated with development of atrial fibrillation (AF). However, the impact of LVH and LAE and their regression following antihypertensive therapy on AF incidence remains unclear. Purpose This study aimed to investigate the impact of changes in the LVH and LAE status on the occurrence of new-onset AF (NOAF). Methods This retrospective analysis included patients with sinus rhythm who underwent echocardiography at hypertension diagnosis and after 6–18 months. LVH was defined as LV mass index >115 g/m2 (men) and >95 g/m2 (women), and LAE was defined as LA volume index >42 ml/m2. LVH and LAE regression was defined as the absence of LVH and LAE on follow-up echocardiography, respectively. The occurrence of NOAF was assessed in relation to changes in LVH and LAE status. Results Among the 1,464 patients included in the study, 163 (11.1%) patients developed NOAF during a median follow-up of 63.8 months (interquartile range, 35.9–128.5 months). On average, 12 electrocardiograms per patient were reviewed for AF detection. New-onset LVH (adjusted HR 1.88, 95% CI 1.20–2.94, P=0.006) and LAE (adjusted HR 1.89, 95% CI 1.05–3.40, P=0.034) were significant predictors of NOAF. Conversely, regression of LVH (adjusted HR 0.51, 95% CI 0.280.91, P=0.022) or LAE (adjusted HR: 0.30, 95% CI 0.15–0.63, P=0.001) after antihypertensive therapy was associated with a reduced risk of NOAF. The risk of NOAF was higher in patients with LVH and LAE together (adjusted HR 4.30, 95% CI 2.81–6.56, P<0.001) than in those with either LVH or LAE, or those with neither, as determined by follow-up echocardiography. Conclusion In patients with hypertension and sinus rhythm, regression of LVH and LAE following antihypertensive therapy is associated with a decreased incidence of NOAF, whereas newly developed LVH or LAE is associated with a higher risk of NOAF. The changes in left heart geometry can serve as a predictive marker for NOAF in patients with hypertension.

Verification of intra- and inter-atrial conduction during Bachmann's bundle pacing using longitudinal bi-atrial strain

Abstract Introduction Although atrial septal pacing has been reported to reduce atrial fibrillation (AF) burden, there is less evidence regarding its effect on the prevention of permanent AF and the improvement of long-term clinical outcomes. However, Bachmann's bundle pacing (BBp), which features P-wave morphology similar to sinus rhythm and shortened P-wave duration (PWD), was reported to significantly reduce permanent AF recurrences and occurrences compared with right atrial appendage pacing (RAAp) and non-specific right septal pacing. Purpose Possible mechanisms for AF suppression with BBp are that fast inter-atrial conduction through BB decreases global atrial activation time and the dispersion of the overall atrial refractoriness, and it prevents the decrease in left ventricular filling and increase in left atrial pressure associated with delayed left atrial contraction. Intra-and inter-atrial conduction during BBp was evaluated using longitudinal bi-atrial strain. Methods In patients with successful BBp implantation defined by electrocardiographic criteria using SelectSecure pacing lead and C315 delivery catheter (Medtronic, Inc), both left atrium (LA) and right atrium (RA) global longitudinal strain (GLS) in simultaneous phases were measured using Philips Ultrasound Workspace 2D Strain in apical 4-chamber view during atrial pacing to assess intra- and inter-atrial conduction delay. The atrial GLS were measured semi-automatically, and the strain rate was analyzed in the three segments of septal wall, lateral wall, and roof and their average. The negative peak of strain rate during atrial systole was the starting point of atrial contraction, and time to peak (TTP) was measured. The difference in TTP between septal and lateral walls in each atrium was measured as intra-atrial conduction delay and the difference in average TTP between LA and RA as inter-atrial conduction delay. Results Ten patients who underwent successful BBp were enrolled (Sick sinus syndrome: 3, advanced atrioventricular block: 2, complete atrioventricular block: 5). At implantation, bipolar atrial electrogram amplitude was 2.03±0.93 mV, atrial lead impedance was 632.7±157.6 Ω, and atrial pacing threshold was 0.7±0.2 V at 0.4 ms. The PWD during sinus rhythm on the 12-lead ECG was 132.8±10.6 ms, while during BBp it was 108.0±11.9 ms, which was significantly shorter in the BBp group (p<0.001). The intra-atrial conduction delay in RA and LA was 10.9 ± 12.1 ms and 12.1 ± 17.3 ms, respectively, and the inter-atrial conduction delay was 6.6 ± 8.6 ms. On the other hand, for the 10 RAAp and 10 sinus rhythm patients as control groups, the inter-atrial conduction delay was 29.7±13.8 ms and 8.5±9.5 ms, respectively. BBp had significantly less inter-atrial conduction delay than RAAp (p=0.005) and was comparable to sinus rhythm (p=0.719). Conclusion Longitudinal bi-atrial strain suggested that BBp significantly reduced inter-atrial delay and it might be effective in AF suppression.Longitudinal bi-atrial strain

Predicting 1-year atrial fibrillation risk from a patch-based ambulatory ECG monitoring without atrial fibrillation

Abstract Introduction Early identification of atrial fibrillation (AF) can enable interventions that reduce cardiovascular events. However, AF remains undiagnosed in about 10-20% of affected individuals, and paroxysmal AF often remains undetected despite the use of in-clinic ECGs, consumer smartwatch ECGs, or ambulatory ECG monitoring. We therefore investigated whether ambulatory ECG patch-based monitoring without AF can predict AF in the subsequent 1-year post monitoring. Purpose This study aims to validate a machine-learning model for AF prediction within 1-year post-wear, based on the observation of non-AF single-lead ECG recordings. Methods We considered a clinically monitored cohort of 67,296 individuals wearing multiple single-lead ECG multi-day ambulatory monitoring patches as part of real-world care. For all selected individuals, the first patch recorded no occurrences of AF and was worn for a minimum of 6.5 days. We assess the risk of future AF based on the raw ECG, heartrate variability, frequency of ectopic beats, age and gender (ECG model), which is then compared with the risk assessment by a model based on age and gender (Baseline model). We then observe AF incidence on subsequent patches worn within one year from the first patch. We evaluated the model's accuracy by observing the number of AF cases identified (or missed) among the individuals with highest risk according to the model. Results In the clinically monitored cohort, a total of 3463 individuals experienced AF within the next year (incidence 5.1%) after a first AF-free monitoring period of a minimum 6.5 days. The receiver operating characteristic (ROC) curve shows an area under the curve (AUC) for the ECG model of 0.75 (95% CI: [0.74, 0.76]), and for the Baseline model of 0.66 (CI: [0.65, 0.67]). When selecting the top 20% (13,459) participants with the highest risk and verifying who developed AF in the following 1-year, we obtain positive prediction value (PPV) or precision of 12% and sensitivity (recall) of 46% for the ECG model (which correctly identifies 1,594 individuals with incident AF), and of 8% and 29%, respectively, for the Baseline model (p-value<0.001). (Figure) Conclusion A machine learning model using as input an AF-free single-lead ECG can quantify the risk of observing AF in a population including individuals with low burdens of paroxysmal or new onset of AF within 1 year. Further research and validation are needed to enhance the interpretability and clinical applicability of the model, while prediction may be further improved with clinical AF diagnoses ascertained from other data sources. The findings of this study have important implications for the early detection and management of AF, potentially enabling earlier intervention and improved outcomes in individuals with undiagnosed AF.

Identification of genetic variants associated with exercise-induced atrial fibrillation in high-performing racehorses

Abstract Background Atrial fibrillation (AF) is the most common cardiac arrhythmia in athletes. Despite a lower burden of classical cardiovascular risk factors, the prevalence of AF in athletes is comparable to that in the general population of similar age (~13%, mean age 65.5), suggesting that exercise-induced AF may have different underlying mechanisms. The prevalence of AF in thoroughbred (TB) and standardbred (STB) racehorses is also relatively high (~5%), suggesting exercise as an independent risk factor. Due to selective breeding and complete control of pedigrees, racehorses are well-suited for genetic studies. Common and rare genetic variation explain a substantial part of AF variance, but no study has identified genetic variants associated with exercise-induced AF in any species. Objective In this project, we aimed to use the racehorse as a model to identify genetic variants associated with exercise-induced AF, and in a future study, possibly replicate the results in human athletes. Here we present preliminary results from the genome-wide association study (GWAS) of AF in racehorses. Methods We collected blood or hair samples from 181 STB and TB racehorses in which 71 had paroxysmal or persistent AF verified by ECG. We extracted DNA and performed whole-genome genotyping using a commercial equine genotyping platform (670k markers). We phased and imputed un-genotyped markers and increased the sample size of the control group, using publicly available equine data from similar breeds from the European Nucleotide Archive. We conducted a GWAS of 7.85 million markers in 71 cases and 296 controls using PLINK2 with covariates adjusted for population stratification, batch and sex. Results We identified one significant locus downstream of the protocadherin gene PCDH18 associated with AF in racehorses. The same locus has been associated with the ECG-trait P-wave terminal force in humans. Changes in P-wave terminal force is associated with increased atrial size, delayed interatrial conduction, left ventricular fibrosis and left atrial function, and considered a good predictor of AF occurrence. Several non-significant but interesting signals were also identified including the genes SLC6A15 (amino acid transport), MYBPH (myosin binding), MYF6 and MYOG (myoblast differentiation). Conclusion In these preliminary results, we have identified a new genetic locus associated with AF in racehorses. In addition, we have identified several candidate genes for further studies to elucidate the genetic background of exercise-induced AF. We aim to replicate our findings in a population of human athletes. Our results may aid the development of risk prediction tools for exercise-induced AF and new drugs for tailored treatment of AF in general.

Comparative study of the effects of preferential left ventricular and biventricular pacing on echocardiographic and cardiorespiratory indices and clinical status of heart failure patients: preliminary

Abstract Introduction Nonresponse to cardiac resynchronization therapy (CRT) has been related with right ventricular dysfunction. Preferential left ventricular pacing (pLV-P) can achieve left ventricle resynchronization allowing for intrinsic activation of the right side, and benefit cardiac output while reducing atrial fibrillation occurrence. Moreover, the AdaptivCRT® algorithm also automatically adjusts interventricular (V-V) delay every minute. Methods We evaluated the effects of a pLVP algorithm on 100 systolic heart failure patients ( all Caucasians, 49% male; 67 +/- 8 years old; 51% ischemic cardiomyopathy; 44% diabetics; NYHA II-III) following randomization to standard biventricular pacing and pLVP, on echocardiographic and cardiopulmonary exercise test indices of functional status. Device programming was based on echocardiography-evaluated maximization of stroke volume and subsequent interventricular and atrioventricular delay adjustments delegated to the device. The follow-up consisted of 6 and 12-months visits; after the 1rst month of optimizing maximum CRT response. Results Significant comparative effects of pLV-P over optimized CRT were noted regarding right ventricle systolic velocity in TDI at 12-months from baseline (mean (SE); 4.5(0.8), p=0.035); decrease in end-diastolic volume of left ventricle (mean (SE); 11.33(7), p=0.035); decrease in right ventricle strain mean ((SE); 9.2(2.1), p=0.03). According to other echocardiographic indices, again taking into account baseline levels, patients in pLV-P group exhibited lower E/e value at 6-months (mean (SE); 8.390(4,3), p=0.04), and at 12 -months (mean (SE); 7.45(3.9), p=0.035); improved values in left atrium contractility strain at 12-months (mean (SE); 8.390(0.8), p=0.04); a borderline improvement in left ventricular ejection fraction (mean (SE); 8.7(433), p=0.05) at 12-months; and borderline improvement in left ventricular longitudinal strain at 6-months (mean (SE); 4.9(2.6), p=0.035), compared to optimized CRT. In CPET, taking into account baseline levels, patients in the pLVP group showed higher METs at 12-months (mean (SE); 1,16(0.8), p=0.03) compared to opt CRT group; higher predicted Ventilation rate (%) even from 6-months (mean (SE); 8.167(5,7), p=0.03) and higher predicted peak VO2 (%) at 6 months (mean (SE); 34,13(14), p=0.03) and borderline significance at 12 months (mean (SE); 4.88(3), p=0.08), compared to opt CRT. Conclusions In the preliminary findings of READAPT study, it seems that pLVP optimized by a standardized echocardiographic protocol in patients with preserved AV conduction and LBBB, can achieve improvement in parameters of right ventricular and left atrium structure and function, as well as in survival-predictive parameters of CPET compared to optimized CRT during the 12-months of follow-up.

Association between postoperative atrial fibrillation after coronary artery bypass grafting and short-term clinical outcomes

BackgroundDespite advances in prevention and treatment, postoperative atrial fibrillation (POAF) is the most common type of complication undergoing cardiac surgery. This study aimed to identify the relationship between POAF and clinical outcomes after coronary artery bypass graft.MethodsIn this cross-sectional study, we retrospectively reviewed the medical records of 324 patients who had undergone coronary artery bypass grafting in an intensive care unit between 2010 and 2019 at a tertiary hospital in Korea. Propensity score matching was used to estimate a 1:1 match (without: with POAF) using seven covariates to overcome selection bias. Kaplan–Meier survival analysis and Cox proportional hazards modeling were performed to determine the effect on intensive care unit readmission and length of hospital stay.ResultsAfter controlling for covariates, 1:1 matching was performed for 91 patients in each group. The occurrence of postoperative atrial fibrillation was found to increase the probability of readmission to the intensive care unit, with a 23% reduced probability of readmission for every 10% increase in left ventricular ejection fraction. Multivariate analysis indicated that postoperative atrial fibrillation, chronic obstructive pulmonary disease as a comorbidity, and preoperative hemoglobin were factors affecting the length of hospitalization after surgery. The Kaplan–Meier survival analysis results indicated that the without POAF group had a higher survival rate than the with POAF group.ConclusionsHealthcare professionals should recognize negative factors such as postoperative atrial fibrillation and abnormal hematologic parameters that impact major clinical outcomes in patients and may require closer monitoring before and after coronary artery bypass grafting.

Atrial Fibrillation in Elite Athletes: A Comprehensive Review of the Literature.

Although the benefits of exercise training have been shown repeatedly in many studies, its relationship with the occurrence of atrial fibrillation (AF) in competitive athletes still remains controversial. In the present review, we sought to demonstrate a comprehensive report of the incidence, pathophysiology, and therapeutic approaches to AF in elite athletes. A 2 to 10 times higher frequency of AF has been shown in many studies in high-intensity endurance athletes compared to individuals who do not exercise. Moreover, a U-shaped relationship between male elite athletes and AF is demonstrated through this finding, while the type and the years of physical activity seem to relate to AF development. A strong correlation seems to exist among the type of exercise (endurance sports), age (>55 years), gender (males), and the time of exercise training, all contributing to an increased risk of AF. The pathophysiology of AF still remains unclear; however, several theories suggest that complex mechanisms are involved, such as bi-atrial dilatation, pulmonary vein stretching, cardiac inflammation, fibrosis, and increased vagal tone. Elite athletes with AF require a comprehensive clinical evaluation and risk factor optimization, similar to the approach taken for nonathletes. Although anticoagulation and rate or rhythm control are cornerstones of AF management, there are still no specific guidelines for elite athletes.