Inter-Relationships of Atrial Fibrillation and Atrial Flutter

Atrial fibrillation detection via contactless radio monitoring and knowledge transfer

Atrial fibrillation (AF) has been a prevalent and serious arrhythmia associated with increased morbidity and mortality worldwide. The Electrocardiogram (ECG) is considered as the golden standard for AF diagnosis. However, current ECG is primarily used only when symptoms arise or for occasional checkups due to the necessity of contact-based measurements. This limitation results in difficulty of capturing early-stage AF episodes and missed opportunities for timely intervention. Here we introduce a contactless, operation-free, and device-free AF detection framework utilizing artificial intelligence (AI)-powered radio technology. Our approach analyzes the mechanical motion of the heart using radar sensing and leverages AI-powered knowledge transfer from established clinical ECG diagnostic practices to read AF-associated motion patterns precisely. Our system is evaluated on 6258 outpatient visitors, including 229 with AF, and achieves AF detection with a sensitivity of 0.844 (95% Confidence Interval (CI), 0.790-0.884) and a specificity of 0.995 (95% CI, 0.993-0.997), which is comparable to the performance of ECG-based methods. We also provide initial evidence that this system could be deployed in a practical daily life scenario, detecting AF before traditional clinical diagnosis routines. These results highlight its potential to support feasible lifelong proactive monitoring, covering the full spectrum of AF progression.

Prognostic impact of atrial fibrillation and atrial flutter in patients with non-ST-segment elevation acute coronary syndrome

INTRODUCTION AND OBJECTIVES

Arrhythmias such as atrial fibrillation and atrial flutter (AF/AFl) complicate the management of patients with non-ST-segment elevation acute coronary syndrome (NSTEACS). The aim of this study was to analyze the prognostic impact of AF/AFl in this clinical setting.

METHODS

The IMPACT-TIMING-GO is a prospective, multicenter registry that enrolled patients with NSTEACS undergoing invasive management. In this subanalysis, patients were categorized based on the presence of AF/AFl (either pre-existing or occurring during admission). Clinical management and complications were assessed both during hospitalization (using a composite endpoint of death, renal failure, ventricular arrhythmias, delirium, new infarction, mechanical complications, and major bleeding) and after 1 year of follow-up (using a composite endpoint of death, cardiovascular admissions, and major bleeding).

RESULTS

A total of 1020 patients (mean age, 66.8±12.7 years; 23.5% women) were included. Of these, 79 (7.7%) had prior AF/AFl, and 37 (3.6%) developed de novo AF/AFl during admission. Patients with AF/AFl were older and had a higher comorbidity burden, with de novo AF/AFl being associated with greater clinical severity. After multivariate adjustment, only de novo AF/AFl, and not previous AF/AFl, was independently associated with the composite endpoint of in-hospital complications (OR, 5.12; 95%CI, 2.30-11.43; P <.001 vs OR, 1.70, 95%CI, 0.91-3.58; P=.166) and adverse events at 1 year (HR, 1.95; 95%CI, 1.02-3.76; P=.045 vs HR, 1.02, 95%CI, 0.55-5.86; P=.957).

CONCLUSIONS

In patients with NSTEACS, de novo AF/AFl is independently associated with higher rates of both in-hospital and follow-up complications.

Evaluation of risk factors for long-term atrial fibrillation development in patients undergoing typical atrial flutter ablation: a multicenter pilot study

BACKGROUND

Atrial flutter (AFL) and atrial fibrillation (AF) are the most commonly detected supraventricular arrhythmias and share similar pathophysiological mechanisms. After the successful ablation of AFL, AF frequently occurs in the long-term follow-up. As emphasized in some studies, certain mechanisms seem to predispose to the development of AF in AFL patients, and approximately 20% of these patients have accompanying AFL.

PURPOSE

We aimed to analyze independent risk factors that predict the development of AF in patients who underwent typical AFL ablation.

METHODS

This was a multicenter, cross-sectional, and retrospective study. A total of 442 patients who underwent typical AFL ablation at three different centers between January 1, 2018 and January 1, 2022 were included retrospectively. After the ablation procedure the patients were divided into those who developed AF and those who did not. The patients were followed up for an average of 12 (4-20) months. In the post-procedural period, atrial arrhythmias were investigated with 24‑h Holter and ECG at 1 month, 6 months, and 12 months and then at 6‑month intervals thereafter.

RESULTS

Overall, AF developed in 206 (46.6%) patients in the long-term follow-up. Age, hypertension (HT), obstructive sleep apnea syndrome (OSAS), previous cerebrovascular accident (CVA), left atrium anteroposterior diameter, severe mitral regurgitation, hemoglobin, blood glucose, and HbA1c values were found to be significant in univariable analysis. According to multivariable analysis, HT (p = 0.014; HR: 1.483 [1.084-2.030]), OSAS (p = 0.008; HR: 1.520 [1.117-2.068]) and previous CVA (p = 0.038; HR: 1.749 [1.031-2.968]) were independently associated with the development of AF in AFL patients who underwent ablation procedure.

CONCLUSION

In the present study, we found that HT, OSAS, and previous CVA were independently correlated with the development of AF in the long-term follow-up of patients who underwent typical AFL ablation. We consider that AFL patients with such risk factors should be followed up closely following cavotricuspid isthmus ablation for the development of AF.

Comparison of a Novel Temperature-Controlled Diamond-Tip Catheter and a Power-Controlled Gold-Tip Catheter for the Irrigated Ablation of Cavotricuspid Isthmus-Dependent Atrial Flutter

Background/Objectives: Radiofrequency (RF) ablation of the cavotricuspid isthmus (CTI) is a recommended treatment option for typical atrial flutter (AFL). While power-controlled ablation has been the current standard, a novel temperature-controlled ablation system has been introduced. We aimed to compare the procedural efficacy and one-year outcome of a temperature-controlled diamond-tip catheter with an established power-controlled gold-tip catheter. Methods: Consecutive patients undergoing ablation of CTI-dependent AFL using a power-controlled catheter or the novel temperature-controlled catheter were enrolled. Patients were followed up using a 7-day electrocardiogram after 3, 6, and 12 months. The primary endpoint was acute efficacy (procedural success, total RF, and procedure time). The secondary endpoint was the recurrence of typical AFL during follow-up. Results: In total, 38 patients undergoing temperature-controlled ablation were enrolled and compared to 283 patients undergoing power-controlled ablation. A bidirectional CTI block was achieved in 100% in the temperature-controlled group and 97.5% in the power-controlled group (p = 0.7). The total RF time (median: 192 sec (IQR 138-311) vs. 643 sec (IQR 386-1079), p < 0.001) and total procedure time (median: 45 min (IQR 34-57) vs. 52 min (IQR 39-70), p = 0.01) were shorter with temperature-controlled ablation. At the one-year follow-up, there was no difference in the recurrence of typical AFL between groups. Conclusions: Utilization of temperature-controlled ablation for typical AFL increased procedural efficiency with shorter RF and procedure times compared to power-controlled ablation. The recurrence rate of typical AFL after one year was low and did not differ amongst groups.

Concomitant pulmonary vein isolation for induced atrial fibrillation to reduce future risk of atrial fibrillation after ablation for isolated atrial flutter

BACKGROUND

A significant proportion of patients with isolated atrial flutter will have atrial fibrillation (AF) after cavotricuspid isthmus (CTI) ablation.

OBJECTIVE

The aim of this study was to determine whether concomitant pulmonary vein isolation (PVI) could reduce the incidence of new-onset AF (NOAF) in the setting of inducible AF after CTI ablation.

METHODS

A total of 275 consecutive patients with isolated atrial flutter who successfully underwent CTI ablation were included. Patients were stratified into the induced AF group (55 patients) and the noninduced AF group (220 patients) on the basis of the inducibility of AF. Subsequently, the induced AF group was randomly divided into a PVI group (28 patients) and non-PVI (27 patients) group.

RESULTS

During 27.0 ± 6.0 months of follow-up, the PVI group (7.1% vs 51.9% [P < .001]; hazard ratio [HR], 0.103 [95% confidence interval for HR, 0.038-0.278; P < .001]) and noninduced AF group (13.2% vs 51.9% [P < .001]); HR, 0.207 [95% confidence interval for HR, 0.073-0.586; P < .001]) exhibited substantially lower incidence and risk of NOAF compared with the non-PVI group. Kaplan-Meier analysis showed that history of hypertension, cardiovascular disease, and heart failure and larger body mass index, larger left atrial diameter, and lower left ventricular ejection fraction were identified predictors of NOAF.

CONCLUSION

Inducibility of AF during CTI ablation is positively associated with an increased risk of NOAF, whereas concomitant PVI for induced AF can significantly reduce the incidence of NOAF.

Antithrombotic therapy in atrial flutter: To anticoagulate or not, that is the question

Atrial fibrillation (AF) represents an arrhythmia fraught with significant morbidity, mortality, and financial burden for the health care system. Less attention is given to atrial flutter (AFL), which may occur as a stand-alone arrhythmia or coexist with AF in the same patient. Moreover, it is known that AF frequently develops after AFL ablation. Despite different pathophysiologies of AF and AFL, current guidelines provide identical indications for anticoagulation therapy in both arrhythmias, given the lack of trials in patients with AFL. This study attempts at providing an up-to-date literature review on the thromboembolic risk profile in AFL, focusing on differences between AFL and AF. Echocardiographic studies showed that the presence of spontaneous echocardiographic contrast (SEC) and thrombus are much less prevalent in patients with AFL than in those with AF. Patients with AFL had overall better left atrial appendage (LAA) function and lower coagulation marker levels than did patients with AF. Observational studies showed a significantly lower risk of stroke in patients with AFL than in those with AF. One study found a significantly higher ischemic stroke incidence in the AFL cohort only at CHA2DS2-VASc scores from 5 to 9 than in patients without AF or AFL. These findings imply that the thromboembolic risk inherent in AFL seems lower than that in AF. This should be considered in the context of a high chance of permanent AFL termination after successful cavotricuspid isthmus ablation, in contrast to the chronic clinical nature of AF. Although thromboembolic risk exists in AFL, prospective studies are warranted to establish the true prothrombotic properties of AFL, allowing the reassessment of anticoagulant treatment strategy.

Impact of pulmonary vein isolation on atrial arrhythmias in patients with typical atrial flutter: systematic review and meta-analysis of randomized clinical trials

Aims

Cavotricuspid isthmus (CTI) ablation is the current ablation treatment for typical atrial flutter (AFL). However, post-ablation atrial tachyarrhythmias, mostly in the form of atrial fibrillation (AF), are frequently observed after CTI ablation. We aimed to evaluate the effectiveness and safety of concomitant or isolated pulmonary vein isolation (PVI) in patients with typical AFL scheduled for ablation.

Methods and results

Electronic databases (PubMED, EMBASE, Clinicaltrials.gov) were searched through July, 2024. Randomized controlled trials (RCTs) were eligible if comparing PVI ± CTI ablation vs. CTI alone. The primary outcomes were any sustained atrial arrhythmia, typical AFL relapse, and AF. Secondary outcomes were need for redo-ablation or antiarrhythmic drugs. Random-effects and fixed-effects meta-analyses were undertaken for each individual outcome. Seven RCTs, with a total of 902 patients, were included. Comparing to CTI ablation alone, PVI ± CTI was more effective in preventing atrial tachyarrhythmias [risk ratio (RR) = 0.57, 95% CI: 0.41-0.79, P = 0.0007, I 2 = 50%, number needed to treat (NNT) = 4.1]. The results were driven mainly by a reduction of new onset/recurrent AF (RR = 0.41, 95% CI: 0.27-0.61, P < 0.0001, I 2 = 0%, NNT = 3.3), whereas there were no differences in typical AFL relapse (RR = 1.52, 95% CI: 0.63-3.66, P = 0.35, I 2 = 9%). Major complication rate was low and comparable across groups, although uncomplicated pericardial effusion was higher in PVI ± CTI (1.8% vs. 0.0%, P = 0.04). Results were comparable for the sub-analysis of PVI alone vs. CTI ablation.

Conclusion

In patients with typical AFL, PVI ± CTI ablation is more effective than CTI alone in reducing the atrial tachyarrhythmias and subsequent AF during follow-up, without affecting major complications rate. These results set the rationale for a well-designed, larger-scale RCT comparing both strategies.

Potential Causal Association Between Atrial Fibrillation/Flutter and Primary Open-Angle Glaucoma: A Two-Sample Mendelian Randomisation Study

Background: A few studies have reported controversial relationships between atrial fibrillation/flutter (AF/L) and primary open-angle glaucoma (POAG). This study aimed to investigate the potential causal relationship between AF/L and POAG. Methods: Single-nucleotide polymorphisms associated with exposure to AF/L were selected as instrumental variables with significance (p < 5.0 × 10-8) from a genome-wide association study (GWAS) by FinnGen. The GWAS summary of POAG from the UK Biobank was used as the outcome dataset. A two-sample Mendelian randomisation (MR) study was performed to assess the causal effects of AF/L on POAG. In addition, potential confounders, including hypertension, autoimmune hyperthyroidism, sleep apnoea, and alcohol use disorder, were assessed using multivariable MR analysis. Results: There was a significant causal association of AF/L with POAG (odds ratio [OR] = 1.26, 95% confidence interval [CI] = 1.07-1.48, p = 0.005 using inverse-variance weighting [IVW]). Multivariable MR analysis confirmed a causal association of AF/L with POAG (OR = 1.24, 95% CI = 1.02-1.51, p = 0.034 using IVW), but hypertension, hyperthyroidism, sleep apnoea and alcohol use disorder did not show significant causal associations with POAG (all p > 0.05). Conclusions: This established causal relationship between AF/L and POAG supports the need for further investigation into the role of AF/L as a possible risk factor for POAG. Further research is required to confirm these findings.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

Electrophysiological predictors of susceptible atrial substrate for the onset and recurrence of atrial fibrillation

BACKGROUND

The atrial electroanatomic substrate is an essential component in the pathogenesis of atrial fibrillation (AF). However, the electrophysiological markers of susceptible atria for AF are not well-characterized. This study aimed to assess atrial conduction indices on surface electrocardiogram (ECG) and intracardiac electrogram (EGM) as predictors of initiation and recurrence of AF after successful ablation.

METHODS

We studied all consecutive patients who underwent electrophysiological study and catheter ablation for AF (study group) or atrioventricular nodal reentrant tachycardia (AVNRT) (control group) from 2013 to 2018. Atrial conduction indices were measured on ECG and EGM during the electrophysiology study. Clinical data was obtained from the medical record.

RESULTS

A total of 387 patients with AF (mean age 63 years, 31% female) were studied and compared to 94 patents in control group. The initiation of AF was associated with significant prolongation of atrial conduction indices on ECG and EGM (p < 0.05). During a mean follow up of 5 ± 2 years, recurrence of AF (48%) after successful ablation occurred in patients with prolonged P wave duration, left atrial (LA) conduction interval, proximal to distal coronary sinus (pCS-dCS) interval, and P wave to dCS interval (p < 0.05). Machine learning modeling determined that pCS-dCS interval, QRS duration, and LA duration in leads V1 and II are most impactful conduction indices in association with AF recurrence.

CONCLUSION

Prolonged atrial conduction intervals, particularly LA (pCS-dCS), indicate susceptible substrate for the onset and the recurrence of AF after ablation. LA conduction indices can facilitate early detection and management of AF.

Cryoballoon pulmonary vein isolation as first-line treatment of typical atrial flutter: long-term outcomes of the CRAFT trial

BACKGROUND

CRAFT was an international, multicentre, randomised controlled trial across 11 sites in the United UK and Switzerland. Given the evidence that pulmonary vein triggers may be responsible for atrial flutter (AFL) as well as atrial fibrillation (AF), we hypothesised that cryoballoon pulmonary vein isolation (PVI) would provide greater symptomatic arrhythmia reduction than cavotricuspid isthmus (CTI) ablation, whilst also reducing the subsequent burden of AF. Twelve-month outcomes were previously reported. In this study, we report the extended outcomes of the CRAFT study to 36 months.

METHODS

Patients with typical AFL and no evidence of AF were randomised 1:1 to cryoballoon PVI or radiofrequency CTI. All patients received an implantable loop recorder (ILR) for continuous cardiac rhythm monitoring. The primary outcome was time-to-symptomatic arrhythmia recurrence > 30 s. Secondary outcomes included time-to-first-AF episode ≥ 2 min. The composite safety outcome included death, stroke and procedural complications.

RESULTS

A total of 113 patients were randomised to cryoballoon PVI (n = 54) or radiofrequency CTI ablation (n = 59). Ninety-one patients reconsented for extended follow-up beyond 12 months. There was no difference in the primary outcome between arms, with the primary outcome occurring in 12 PVI vs 11 CTI patients (HR 0.97; 95% CI 0.43-2.20; p = 0.994). AF ≥ 2 min was significantly less frequent in the PVI arm, affecting 26 PVI vs 36 CTI patients (HR 0.48; 95% CI 0.29-0.79; p = 0.004). The composite safety outcome occurred in 5 PVI and 6 CTI patients (p = 0.755).

CONCLUSION

Cryoballoon PVI shows similar efficacy to radiofrequency CTI ablation in reducing symptomatic arrhythmia recurrence in patients presenting with isolated typical AFL but significantly reduces the occurrence of subsequent AF.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

The incidence of atrial fibrillation detected by implantable loop recorders: a comparison between patients with and without embolic stroke of undetermined source

Aims

Stroke is the most debilitating outcome of atrial fibrillation (AF). The use of implantable loop recorders increases the detection of AF episodes among patients with embolic stroke of undetermined source. The significance of device-detected AF, or subclinical AF, is unknown. This study aimed to compare the incidence of AF detected by implantable loop recorder in patients with and without embolic stroke of undetermined source.

Methods and results

We retrospectively studied all patients without known AF who were referred to our institution for implantable loop recorder implantation following embolic stroke of undetermined source, syncope, or palpitations from March 2009 to November 2019. The primary endpoint was any detection of AF or atrial flutter by implantable loop recorder. Seven hundred and fifty patients were included and followed up for a mean duration of 731 days (SD 443). An implantable loop recorder was implanted following embolic stroke of undetermined source in 323 and for assessment of syncope, palpitations, or another reason in 427 patients. The incidence of AF was significantly (P < 0.001) higher among patients with embolic stroke of undetermined source compared with the non-embolic stroke of undetermined source group; 48.6% vs. 13.8% (for any duration of AF) and 32.2% vs. 12.4% (for AF lasting ≥30 s) both P < 0.001. Kaplan-Meier analysis showed significantly higher incidence of AF for incremental durations of AF up to >5.5 h, but not >24 h. This was driven by longest AF durations of <6 min and between 5.5 h and 24 h, suggesting a bimodal distribution. In a multivariable Cox regression analysis, embolic stroke of undetermined source independently conferred an almost 5-fold increase in the hazard for any duration of AF.

Conclusion

The incidence of AF is significantly higher amongst embolic stroke of undetermined source vs. non-embolic stroke of undetermined source patients monitored constantly by an implantable loop recorder. A high number of embolic stroke of undetermined source survivors have short-duration AF episodes. Further work is needed to determine the optimal treatment strategy of these AF episodes in embolic stroke of undetermined source.

Adulthood weight changes, body mass index in youth, genetic susceptibility and risk of atrial fibrillation: a population-based cohort study

BACKGROUND

Epidemiological evidence on weight change and atrial fibrillation (AF) remains limited and inconsistent. Previous studies on body mass index (BMI) in youth and AF rarely considered subsequent BMI. This study aimed to assess the associations of AF with weight change and BMI in youth, as well as modified effect by genetic susceptibility of AF.

METHODS

The study included 21,761 individuals (mean age 57.8 years) from the Malmö Diet and Cancer cohort. Weight information was obtained at three time points, including recalled weight at age 20 years, measured weight at baseline (middle adulthood), and reported weight at 5-year follow-up examination (late middle adulthood). A weighted genetic risk score of AF was created using 134 variants.

RESULTS

During a median follow-up of 23.2 years, a total of 4038 participants developed AF. The association between weight change from early to middle adulthood and AF risk was modified by sex (Pinteraction = 0.004); weight loss was associated with a lower AF risk in females, but not in males. Conversely, weight gain was positively associated with AF risk in a linear manner in females, whereas increased AF risk appeared only when weight gain exceeded a threshold in males. Participants with weight gain of > 5 kg from middle to late middle adulthood had a 19% higher risk of AF relative to those with stable weight, whereas weight loss showed a null association. Compared to individuals with a lower BMI at age 20 years, those with a BMI above 25 kg/m2 had an increased risk of AF (HR = 1.14; 95% CI: 1.02-1.28), after controlling for baseline BMI; this association was more pronounced in males or those with a lower genetic risk of AF.

CONCLUSIONS

Weight gain in middle adulthood was associated with higher AF risk. Weight loss from early to middle adulthood, but not from middle to late middle adulthood, was associated with a lower risk of AF only in females. Higher BMI in youth was associated with an increased risk of AF, particularly among males or those with a lower genetic risk of AF.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Patients With Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

Atrial fibrillation in embolic stroke of undetermined source: role of advanced imaging of left atrial function

AIMS

Atrial fibrillation (AF) is detected in over 30% of patients following an embolic stroke of undetermined source (ESUS) when monitored with an implantable loop recorder (ILR). Identifying AF in ESUS survivors has significant therapeutic implications, and AF risk is essential to guide screening with long-term monitoring. The present study aimed to establish the role of left atrial (LA) function in subsequent AF identification and develop a risk model for AF in ESUS.

METHODS AND RESULTS

We conducted a single-centre retrospective case-control study including all patients with ESUS referred to our institution for ILR implantation from December 2009 to September 2019. We recorded clinical variables at baseline and analysed transthoracic echocardiograms in sinus rhythm. Univariate and multivariable analyses were performed to inform variables associated with AF. Lasso regression analysis was used to develop a risk prediction model for AF. The risk model was internally validated using bootstrapping. Three hundred and twenty-three patients with ESUS underwent ILR implantation. In the ESUS population, 293 had a stroke, whereas 30 had suffered a transient ischaemic attack as adjudicated by a senior stroke physician. Atrial fibrillation of any duration was detected in 47.1%. The mean follow-up was 710 days. Following lasso regression with backwards elimination, we combined increasing lateral PA (the time interval from the beginning of the P wave on the surface electrocardiogram to the beginning of the A' wave on pulsed wave tissue Doppler of the lateral mitral annulus) [odds ratio (OR) 1.011], increasing Age (OR 1.035), higher Diastolic blood pressure (OR 1.027), and abnormal LA reservoir Strain (OR 0.973) into a new PADS score. The probability of identifying AF can be estimated using the formula. Model discrimination was good [area under the curve (AUC) 0.72]. The PADS score was internally validated using bootstrapping with 1000 samples of 150 patients showing consistent results with an AUC of 0.73.

CONCLUSION

The novel PADS score can identify the risk of AF on prolonged monitoring with ILR following ESUS and should be considered a dedicated risk stratification tool for decision-making regarding the screening strategy for AF in stroke.

Association of typical atrial flutter and cavotricuspid isthmus ablation on clinical recurrence after cryoballoon ablation for atrial fibrillation

Typical atrial flutter commonly occurs in patients with atrial fibrillation (AF). Limited information exists regarding the effects of concurrent atrial flutter on the long-term outcomes of rhythm control. This study investigated the association between concurrent typical atrial flutter and cavotricuspid isthmus (CTI) ablation and the recurrence of atrial arrhythmia. The data were obtained from a multicenter registry of cryoballoon ablation for AF (n = 2,689). Patients who were screened for typical atrial flutter were included in the analysis (n = 1,907). All the patients with typical atrial flutter underwent CTI ablation. The primary endpoint was the late recurrence of atrial arrhythmia, including AF, atrial flutter, and atrial tachycardia. Among the 1,907 patients, typical atrial flutter was detected in 493 patients (25.9%). Patients with concurrent atrial flutter had a lower incidence of persistent AF and a smaller size of the left atrium. Patients with atrial flutter had a significantly lower recurrence rate of atrial arrhythmia (19.7% vs. 29.9%, p < 0.001). In patients with atrial flutter, the recurrence rate of atrial tachycardia or atrial flutter was more frequent (7.3% vs. 4.7%, p = 0.028), but the recurrence rate of AF was significantly lower (17.0% vs. 29.4%, p < 0.001). Atrial flutter has been identified as an independent predictor of the primary endpoint (adjusted hazard ratio, 0.704; 95% confidence interval, 0.548-0.906; p = 0.006). Typical atrial flutter in patients with AF may serve as a positive marker of the recurrence of atrial arrhythmia, and performing CTI ablation in this population is associated with a reduced likelihood of AF recurrence. Performing routine screening and ablation procedures for coexisting atrial flutter may improve the clinical outcomes of AF.

Red cell distribution width and its polygenic score in relation to mortality and cardiometabolic outcomes

Introduction

Elevated red cell distribution width (RDW) has been associated with a range of health outcomes. This study aims to examine prognostic and etiological roles of RDW levels, both phenotypic and genetic predisposition, in predicting cardiovascular outcomes, diabetes, chronic kidney disease (CKD) and mortality.

Methods

We studied 27,141 middle-aged adults from the Malmö Diet and Cancer study (MDCS) with a mean follow up of 21 years. RDW was measured with a hematology analyzer on whole blood samples. Polygenic scores for RDW (PGS-RDW) were constructed for each participant using genetic data in MDCS and published summary statistics from genome-wide association study of RDW (n = 408,112). Cox proportional hazards regression was used to assess associations between RDW, PGS-RDW and cardiovascular outcomes, diabetes, CKD and mortality, respectively.

Results

PGS-RDW was significantly associated with RDW (Pearson's correlation coefficient = 0.133, p < 0.001). RDW was significantly associated with incidence of stroke (hazard ratio (HR) per 1 standard deviation = 1.06, 95% confidence interval (CI): 1.02-1.10, p = 0.003), atrial fibrillation (HR = 1.09, 95% CI: 1.06-1.12, p < 0.001), heart failure (HR = 1.13, 95% CI: 1.08-1.19, p < 0.001), venous thromboembolism (HR = 1.21, 95% CI: 1.15-1.28, p < 0.001), diabetes (HR = 0.87, 95% CI: 0.84-0.90, p < 0.001), CKD (HR = 1.08, 95% CI: 1.03-1.13, p = 0.004) and all-cause mortality (HR = 1.18, 95% CI: 1.16-1.20, p < 0.001). However, PGS-RDW was significantly associated with incidence of diabetes (HR = 0.96, 95% CI: 0.94-0.99, p = 0.01), but not with any other tested outcomes.

Discussion

RDW is associated with mortality and incidence of cardiovascular diseases, but a significant association between genetically determined RDW and incident cardiovascular diseases were not observed. However, both RDW and PGS-RDW were inversely associated with incidence of diabetes, suggesting a putative causal relationship. The relationship with incidence of diabetes needs to be further studied.

Ability of the DANCAMI to predict the risk ischemic stroke and mortality in patients with atrial fibrillation/flutter

OBJECTIVES

Comparison of the danish comorbidity index for acute myocardial infarction (DANCAMI), the charlson comorbidity index (CCI), the elixhauser comorbidity index (ECI), and the CHA2DS2-VASc score to predict ischemic stroke, cardiovascular mortality, and all-cause mortality after atrial fibrillation/flutter.

MATERIALS AND METHODS

A population-based cohort study of all Danish patients with incident atrial fibrillation/flutter during 2000-2020 (n=361,901). C-Statistics were used to evaluate the discriminatory performance for predicting 1 and 5-year risks of the outcomes for a baseline model (including age and sex) +/- the individual indices.

RESULTS

For the DANCAMI, the 5-year risk did not increase with comorbidity burden for ischemic stroke (5.9% for low vs. 5.6% for severe) but did increase for cardiovascular mortality (10% for low vs. 16% for severe) and all-cause mortality (33% for low vs. 61% for severe). C-Statistics for predicting 5-year ischemic stroke risk were similar for all models (0.64). C-Statistics for predicting 5-year cardiovascular mortality risk were also similar for the baseline (0.76), the DANCAMI (0.77), the CCI (0.76), the ECI (0.76), and the CHA2DS2-VASc (0.76) models. C-Statistics for predicting 5-year all-cause mortality risk were lower for the baseline (0.71) and the CHA2DS2-VASc (0.71) models than for the DANCAMI (0.75), the CCI (0.74), and the ECI (0.74) models. The 1-year C-Statistics were comparable.

CONCLUSION

The DANCAMI predicted ischemic stroke and cardiovascular mortality risks similar to the CCI, the ECI, and the CHA2DS2-VASc. The DANCAMI predicted all-cause mortality risk similar to the CCI and the ECI, but better than the baseline and the CHA2DS2-VASc.

The EAT-Lancet diet, genetic susceptibility and risk of atrial fibrillation in a population-based cohort

BACKGROUND

The EAT-Lancet Commission proposed a global reference diet with both human health benefits and environmental sustainability in 2019. However, evidence regarding the association of such a diet with the risk of atrial fibrillation (AF) is lacking. In addition, whether the genetic risk of AF can modify the effect of diet on AF remains unclear. This study aimed to assess the association of the EAT-Lancet diet with the risk of incident AF and examine the interaction between the EAT-Lancet diet and genetic susceptibility of AF.

METHODS

This prospective study included 24,713 Swedish adults who were free of AF, coronary events, and stroke at baseline. Dietary habits were estimated with a modified diet history method, and an EAT-Lancet diet index was constructed to measure the EAT-Lancet reference diet. A weighted genetic risk score was constructed using 134 variants associated with AF. Cox proportional hazards regression models were applied to estimate the hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

During a median follow-up of 22.9 years, 4617 (18.7%) participants were diagnosed with AF. The multivariable HR (95% CI) of AF for the highest versus the lowest group for the EAT-Lancet diet index was 0.84 (0.73, 0.98) (P for trend < 0.01). The HR (95% CI) of AF per one SD increment of the EAT-Lancet diet index for high genetic risk was 0.92 (0.87, 0.98) (P for interaction = 0.15).

CONCLUSIONS

Greater adherence to the EAT-Lancet diet index was significantly associated with a lower risk of incident AF. Such association tended to be stronger in participants with higher genetic risk, though gene-diet interaction was not significant.

In-hospital complications associated with pulmonary vein isolation with adjunctive lesions: the NCDR AFib Ablation Registry

AIMS

No prior study has been adequately powered to evaluate real-world safety outcomes in those receiving adjunctive ablation lesions beyond pulmonary vein isolation (PVI). We sought to evaluate characteristics and in-hospital complications among patients undergoing PVI with and without adjunctive lesions.

METHODS AND RESULTS

Patients in the National Cardiovascular Data Registry AFib Ablation Registry undergoing first-time atrial fibrillation (AF) ablation between 2016 and 2020 were identified and stratified into paroxysmal (PAF) and persistent AF, and separated into PVI only, PVI + cavotricuspid isthmus (CTI) ablation, and PVI + adjunctive (superior vena cava isolation, coronary sinus, vein of Marshall, atypical atrial flutter lines, other). Adjusted odds of adverse events were calculated using multivariable logistic regression. A total of 50 937 patients [PAF: 30 551 (60%), persistent AF: 20 386 (40%)] were included. Among those with PAF, there were no differences in the adjusted odds of complications between PVI + CTI or PVI + adjunctive when compared with PVI only. Among persistent AF, PVI + adjunctive was associated with a higher risk of any complication [3.0 vs. 4.5%, odds ratio (OR) 1.30, 95% confidence interval (CI) 1.07-1.58] and major complication (0.8 vs. 1.4%, OR 1.56, 95% CI 1.10-2.21), while no differences were observed in PVI + CTI compared with PVI only. Overall, there was high heterogeneity in adjunctive lesion type, and those receiving adjunctive lesions had a higher comorbidity burden.

CONCLUSION

Additional CTI ablation was common without an increased risk of complications. Adjunctive lesions other than CTI are commonly performed in those with more comorbidities and were associated with an increased risk of complications in persistent AF, although the current analysis is limited by high heterogeneity in adjunctive lesion set type.

Preterm Birth, Small for Gestational Age, and Large for Gestational Age and the Risk of Atrial Fibrillation Up to Middle Age

Importance

Adverse birth outcomes, including preterm birth, small for gestational age (SGA), and large for gestational age (LGA) are associated with increased risks of hypertension, ischemic heart disease, stroke, and heart failure, but knowledge regarding their associations with atrial fibrillation (AF) is limited and inconsistent.

Objective

To investigate whether preterm birth, SGA, or LGA are associated with increased risks of AF later in life.

Design, Setting, and Participants

This multinational cohort study included Danish, Swedish, and Finnish national health registries. Live singleton births in Denmark from 1978 through 2016, in Sweden from 1973 through 2014, and in Finland from 1987 through 2014, who were followed up until December 31, 2016, in Denmark, December 31, 2021, in Sweden, and December 31, 2014, in Finland were included. Data analyses were performed between January 2021 and August 2022.

Exposures

Preterm birth (less than 37 gestational weeks), SGA (less than 10th percentile birth weight for gestational age), and LGA (more than 90th percentile birth weight for gestational age) identified from medical birth registers.

Main Outcomes and Measures

Diagnosis of AF obtained from nationwide inpatient and outpatient registers. The study team ran multivariable Cox proportional hazard models and flexible parametric survival models to estimate hazard ratios (HRs) and 95% CIs for AF according to preterm birth, SGA, and LGA. Sibling analyses were conducted to control for unmeasured familial factors.

Results

The cohort included 8 012 433 study participants (maximum age, 49 years; median age, 21 years; male, 51.3%). In 174.4 million person-years of follow-up, 11 464 participants had a diagnosis of AF (0.14%; median age, 29.3 years). Preterm birth and LGA were associated with increased AF risk in both the full population cohort and in the sibling analyses; the multivariate HRs from the cohort analyses were 1.30 (95% CI, 1.18-1.42) and 1.55 (95% CI, 1.46-1.63), respectively. Preterm birth was more strongly associated with AF in childhood than in adulthood. Children born SGA had an increased risk of AF in the first 18 years of life but not afterwards.

Conclusions and Relevance

Preterm births and LGA births were associated with increased risks of AF up to middle age independently of familial confounding factors. Individuals born SGA had an increased AF risk only during childhood.

HARDC : A novel ECG-based heartbeat classification method to detect arrhythmia using hierarchical attention based dual structured RNN with dilated CNN

Deep learning-based models have achieved significant success in detecting cardiac arrhythmia by analyzing ECG signals to categorize patient heartbeats. To improve the performance of such models, we have developed a novel hybrid hierarchical attention-based bidirectional recurrent neural network with dilated CNN (HARDC) method for arrhythmia classification. This solves problems that arise when traditional dilated convolutional neural network (CNN) models disregard the correlation between contexts and gradient dispersion. The proposed HARDC fully exploits the dilated CNN and bidirectional recurrent neural network unit (BiGRU-BiLSTM) architecture to generate fusion features. As a result of incorporating both local and global feature information and an attention mechanism, the model's performance for prediction is improved. By combining the fusion features with a dilated CNN and a hierarchical attention mechanism, the trained HARDC model showed significantly improved classification results and interpretability of feature extraction on the PhysioNet 2017 challenge dataset. Sequential Z-Score normalization, filtering, denoising, and segmentation are used to prepare the raw data for analysis. CGAN (Conditional Generative Adversarial Network) is then used to generate synthetic signals from the processed data. The experimental results demonstrate that the proposed HARDC model significantly outperforms other existing models, achieving an accuracy of 99.60%, F1 score of 98.21%, a precision of 97.66%, and recall of 99.60% using MIT-BIH generated ECG. In addition, this approach significantly reduces run time when using dilated CNN compared to normal convolution. Overall, this hybrid model demonstrates an innovative and cost-effective strategy for ECG signal compression and high-performance ECG recognition. Our results indicate that an automated and highly computed method to classify multiple types of arrhythmia signals holds considerable promise.

Cryoballoon Pulmonary Vein Isolation as First-Line Treatment for Typical Atrial Flutter

OBJECTIVE

We aimed to compare cryoballoon pulmonary vein isolation (PVI) with standard radiofrequency cavotricuspid isthmus (CTI) ablation as first-line treatment for typical atrial flutter (AFL).

METHODS

Cryoballoon Pulmonary Vein Isolation as First-Line Treatment for Typical Atrial Flutter was an international, multicentre, open with blinded assessment trial. Patients with CTI-dependent AFL and no documented atrial fibrillation (AF) were randomised to either cryoballoon PVI alone or radiofrequency CTI ablation. Primary efficacy outcome was time to first recurrence of sustained (>30 s) symptomatic atrial arrhythmia (AF/AFL/atrial tachycardia) at 12 months as assessed by continuous monitoring with an implantable loop recorder. Primary safety outcome was a composite of death, stroke, tamponade requiring drainage, atrio-oesophageal fistula, pacemaker implantation, serious vascular complications or persistent phrenic nerve palsy.

RESULTS

Trial recruitment was halted at 113 of the target 130 patients because of the SARS-CoV-2 pandemic (PVI, n=59; CTI ablation, n=54). Median age was 66 (IQR 61-71) years, with 98 (86.7%) men. At 12 months, the primary outcome occurred in 11 (18.6%) patients in the PVI group and 9 (16.7%) patients in the CTI group. There was no significant difference in the primary efficacy outcome between the groups (HR 1.11, 95% CI 0.46 to 2.67). AFL recurred in six (10.2%) patients in the PVI arm and one (1.9%) patient in the CTI arm (p=0.116). Time to occurrence of AF of ≥2 min was significantly reduced with cryoballoon PVI (HR 0.46, 95% CI 0.25 to 0.85). The composite safety outcome occurred in four patients in the PVI arm and three patients in the CTI arm (p=1.000).

CONCLUSION

Cryoballoon PVI as first-line treatment for AFL is equally effective compared with standard CTI ablation for preventing recurrence of atrial arrhythmia and better at preventing new-onset AF.

TRIAL REGISTRATION NUMBER

NCT03401099.

Alcohol and Arrhythmias

The association between alcohol consumption and abnormalities of heart rate and rhythm has long been recognized. Significant attention has focused on the risk of atrial fibrillation (AF) and sudden cardiac death (SCD) with excessive alcohol intake. Recent studies have advanced our understanding of these relationships and provided additional insights into potentially arrhythmogenic mechanisms. However, considerable uncertainty remains, such as the level of consumption at which harm begins and whether alcohol plays a role in other arrhythmias. This review characterizes the spectrum of conduction abnormalities and heart rhythm disorders in relation to alcohol consumption. In addition, it discusses the latest epidemiologic and experimental evidence, the potential importance of beverage type and constituent ingredients, and conflicting information on drink definitions, thresholds, and recommendations.

Relationships Between Atrial Flutter and Fibrillation: The Border Zone

Atrial flutter and fibrillation have been inextricably linked in the study of electrophysiology. With astute clinical observation, advanced diagnostic equipment in the Electrophysiology Laboratory, and thoughtful study of animal models, the mechanism and inter-relationship between the 2 conditions have been elucidated and will be reviewed in this article. Though diagnosis and management of these conditions have many similarities, the mechanisms by which they develop and persist are quite unique.

Prophylactic Cavotricuspid Isthmus Ablation in Atrial Fibrillation without Documented Typical Atrial Flutter: A Systematic Review and Meta-analysis

Background: The advantage of prophylactic cavotricuspid isthmus (CTI) ablation for AF patients without documented atrial flutter is still unclear. The present study aimed to evaluate the role of prophylactic CTI ablation in this population. Methods: A systematic review and meta-analysis study was conducted. The overall effects estimation was conducted using random effects models. The pooled effects were presented as the risk difference and standardised mean difference for dichotomous and continuous outcomes, respectively. Results: A total of 1,476 patients from four studies were included. The risk of atrial tachyarrhythmias following a successful catheter ablation procedure was greater in the pulmonary vein isolation + CTI ablation group than pulmonary vein isolation alone group (34.8% versus 28.2%; risk difference 0.08; 95% CI [0.00–0.17]; p=0.04). Prophylactic CTI ablation was associated with a higher recurrent AF rate (33.8% versus 27.1%; risk difference 0.07; 95% CI [0.01–0.13]; p=0.02). Additional prophylactic CTI ablation to pulmonary vein isolation significantly increased the radio frequency application time (standardised mean difference 0.52; 95% CI [0.04–1.01]; p=0.03). Conclusion: This study suggested that prophylactic CTI ablation was an ineffective and inefficient approach in AF without documented typical atrial flutter patients.

The influence of atrial flutter in automated detection of atrial arrhythmias - are we ready to go into clinical practice?"

OBJECTIVE

To investigate the impact of atrial flutter (A_fl) in the atrial arrhythmias classification task. We additionally advocate the use of a subject-based split for future studies in the field in order to avoid within-subject correlation which may lead to over-optimistic inferences. Finally, we demonstrate the effectiveness of the classifiers outside of the initially studied circumstances, by performing an inter-dataset model evaluation of the classifiers in data from different sources.

METHODS

ECG signals of two private and three public (two MIT-BIH and Chapman ecgdb) databases were preprocessed and divided into 10s segments which were then subject to feature extraction. The created datasets were divided into a training and test set in two ways, based on a random split and a patient split. Classification was performed using the XGBoost classifier, as well as two benchmark classification models using both data splits. The trained models were then used to make predictions on the test data of the remaining datasets.

RESULTS

The XGBoost model yielded the best performance across all datasets compared to the remaining benchmark models, however variability in model performance was seen across datasets, with accuracy ranging from 70.6% to 89.4%, sensitivity ranging from 61.4% to 76.8%, and specificity ranging from 87.3% to 95.5%. When comparing the results between the patient and the random split, no significant difference was seen in the two private datasets and the Chapman dataset, where the number of samples per patient is low. Nonetheless, in the MIT-BIH dataset, where the average number of samples per patient is approximately 1300, a noticeable disparity was identified. The accuracy, sensitivity, and specificity of the random split in this dataset of 93.6%, 86.4%, and 95.9% respectively, were decreased to 88%, 61.4%, and 89.8% in the patient split, with the largest drop being in A_fl sensitivity, from 71% to 5.4%. The inter-dataset scores were also significantly lower than their intra-dataset counterparts across all datasets.

CONCLUSIONS

CAD systems have great potential in the assistance of physicians in reliable, precise and efficient detection of arrhythmias. However, although compelling research has been done in the field, yielding models with excellent performances on their datasets, we show that these results may be over-optimistic. In our study, we give insight into the difficulty of detection of A_fl on several datasets and show the need for a higher representation of A_fl in public datasets. Furthermore, we show the necessity of a more structured evaluation of model performance through the use of a patient-based split and inter-dataset testing scheme to avoid the problem of within-subject correlation which may lead to misleadingly high scores. Finally, we stress the need for the creation and use of datasets with a higher number of patients and a more balanced representation of classes if we are to progress in this mission.

Recurrent atrial arrhythmia in a randomised controlled trial comparing contact force-guided and contact force-blinded ablation for typical atrial flutter

BACKGROUND

Contact force (CF)-guided catheter ablation (CA) is a novel technology developed to improve efficacy and reduce complications. In a randomised controlled trial (RCT), we previously documented that after 3 months, rate of persistent conduction block was similar with and without using CF while performing CA for typical atrial flutter (AFL). Clinical effect of CF on recurrent arrhythmia is unknown. Our objective is to study recurrent atrial arrhythmia during 12-month follow-up in a RCT investigating whether CF-guided CA for typical AFL is superior to CF-blinded CA.

METHODS

Patients were randomised 1:1 to CA guided by CF (intervention group) or blinded to CF (control group). After 12 months, patients attended clinical check-up preceded by a 5-day ambulatory Holter monitor recording. Primary outcome was any recurrent atrial arrhythmia ≥ 30 s within 12 months and documented in 12-lead ECG or Holter monitor recording.

RESULTS

We included 156 patients, four patients withdrew consent and two died during follow-up. Thus, 150 patients were included in final analysis. Recurrent arrhythmia was detected in 36 of 77 (47%) patients in the intervention group, and 32 of 73 patients (44%) in the control group (p = 0.51). Atrial fibrillation was detected in 23 (30%) and 29 (40%) patients in the intervention and control groups respectively. AFL was detected in 11 (14%) and 5 (7%) patients in the intervention and control groups respectively.

CONCLUSIONS

Contact force-guided ablation for typical atrial flutter does not reduce recurrent atrial arrhythmia after 12-month follow-up as compared with ablation blinded for contact force.

Prevention of Atrial Fibrillation After Atrial Flutter Ablation With Ramipril (from the PREFACE Study)

The clinical efficacy of the inhibitors of the renin-angiotensin-aldosterone system (RAAS) as an upstream therapy for atrial fibrillation (AF) prevention is controversial. No study has itemized so far the role of RAAS inhibitors in AF prevention after atrial flutter (AFL) ablation. This trial aims to investigate the effect of ramipril compared with placebo on AF occurrence in patients hospitalized for AFL ablation without structural heart disease. The Prevention of Atrial Fibrillation by Inhibition Conversion Enzyme (ICE) After Radiofrequency Ablation of Atrial Flutter (PREFACE) trial was a prospective, multicenter, randomized, double-blind, double-dummy trial depicting the AF occurrence during a 12-month follow-up as the primary end point. A total of 198 patients hospitalized for AFL ablation were enrolled in the trial and randomized to placebo or ramipril 5 mg/day. Patients were followed up during 1 year after AFL ablation using 1-week Holter electrocardiogram at 3, 6, 9, and 12 months. The intention-to-treat population encompassed 97 patients in the ramipril group and 101 patients in the placebo group. The primary end point, such as AF occurrence during the 1-year follow-up, was not different between the 2 groups (p = 0.96). Secondary end points, including the occurrence of supraventricular arrhythmia (p = 0.50), heart failure, stroke, and death, were not different between the 2 groups. Safety outcome parameters, including serious adverse events leading to treatment disruption (p = 0.10), hypotension, impairment of renal function, and elevated serum potassium level, also were not different between the 2 groups. In conclusion, RAAS inhibition using ramipril does not reduce AF occurrence in patients facing AFL ablation during the 1-year follow-up.

Identification of undiagnosed atrial fibrillation using a machine learning risk prediction algorithm and diagnostic testing (PULsE-AI) in primary care: cost-effectiveness of a screening strategy evaluated in a randomized controlled trial in England

OBJECTIVE

The PULsE-AI trial sought to determine the effectiveness of a screening strategy that included a machine learning risk prediction algorithm in conjunction with diagnostic testing for identification of undiagnosed atrial fibrillation (AF) in primary care. This study aimed to evaluate the cost-effectiveness of implementing the screening strategy in a real-world setting.

METHODS

Data from the PULsE-AI trial - a prospective, randomized, controlled trial conducted across six general practices in England from June 2019 to February 2021 - were used to inform a cost-effectiveness analysis that included a hybrid screening decision tree and Markov AF disease progression model. Model outcomes were reported at both individual- and population-level (estimated UK population ≥30 years of age at high-risk of undiagnosed AF) and included number of patients screened, number of AF cases identified, mean total and incremental costs (screening, events, treatment), quality-adjusted-life-years (QALYs), and incremental cost-effectiveness ratio (ICER).

RESULTS

The screening strategy was estimated to result in 45,493 new diagnoses of AF across the high-risk population in the UK (3.3 million), and an estimated additional 14,004 lifetime diagnoses compared with routine care only. Per-patient costs for high-risk individuals who underwent the screening strategy were estimated at £1,985 (vs £1,888 for individuals receiving routine care only). At a population-level, the screening strategy was associated with a cost increase of approximately £322 million and an increase of 81,000 QALYs. The screening strategy demonstrated cost-effectiveness versus routine care only at an accepted ICER threshold of £20,000 per QALY-gained, with an ICER of £3,994/QALY.

CONCLUSIONS

Compared with routine care only, it is cost-effective to target individuals at high risk of undiagnosed AF, through an AF risk prediction algorithm, who should then undergo diagnostic testing. This AF risk prediction algorithm can reduce the number of patients needed to be screened to identify undiagnosed AF, thus alleviating primary care burden.

Anthropometric measures and the risk of developing atrial fibrillation: a Swedish Cohort Study

Aims

Obesity is a risk factor for several cardiovascular diseases (CVDs), including atrial fibrillation (AF). However, it is less clear whether overall fat or abdominal fat distribution are most important for risk of developing AF. This study investigates how different anthropometric measures correlate to the risk of developing clinical AF in the Malmö Diet and Cancer cohort (MDC-cohort).

Methods

The MDC-cohort (n = 25,961) was examined in 1991–1996. The endpoint was clinical AF diagnosed in a hospital setting, and retrieved via linkage with national registers. Hazard Ratios (HR) for incident AF was calculated in relation to quartiles of body mass index (BMI), waist circumference, waist hip ratio, waist height ratio, body fat percentage, weight and height, using Cox regression with adjustment for age, biological (e.g. blood pressure, diabetes, blood lipid levels), and socioeconomic risk factors.

Results

After adjustment for multiple risk factors, the risk of AF was significantly increased in the 4th versus 1st quartile of weight (HR for men/women = 2.02/1.93), BMI (HR = 1.62/1.52), waist circumference (HR = 1.67/1.63), waist to hip ratio (HR = 1.30/1.24), waist to height ratio (1.37/1.39) and body fat percentage (HR = 1.21/1.45) in men/women. Measures of overall weight (BMI, weight) were slightly more predictive than measures of abdominal obesity (waist hip ratio and waist height ratio) both in men and women.

Conclusion

All measures of obesity were associated with increased risk of developing AF. Both overall obesity and abdominal obesity were related to incidence of AF in this population-based study, although the relationship for overall obesity was stronger.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02415-6.

Safety and Effectiveness of Pharmacologic Conversion of Atrial Fibrillation and Flutter: Results of Multicenter Trial. Part II: Assessment of Safety

Aim. We aimed to assess safety and effectiveness of class III antiarrhythmic drug Refralon for conversion of atrial fibrillation (AFib) and flutter (AFl) in post-registration trial and to compare data of primary center (National medical research center in cardiology) with data of other hospitals.

Material and Methods. We performed retrospective cohort study in 727 patients (451 enrolled in primary center and 276 enrolled in other hospitals) admitted between June 24, 2014 and June 24, 2019. Refralon was administered for conversion of AFib and AFl in intense care units in escalating doses (10-30 micrograms/kg) intravenously.

Results. Conversion of AFib and AFl into sinus rhythm was achieved in 53,6% after administration of 10 mcg/kg dose, in 73% after administration of 20 mcg/kg dose and in 91,6% after administration of Refralon in dose up to 30 mcg/kg. No mortality and no major adverse cardiac events registered in our study. Asystole >3.0 sec observed in 5% (35 of 727) of patients): in 5% (24 of 451) of patients enrolled in primary center and in 4% (11 of 276) of patients enrolled in other hospitals; 95% confidence interval (CI) [-0.09; 0.113]. Asystole> 5.0 s observed in 1.7% of patients who further required non-urgent implantation of a permanent pacemaker due to manifestations of sinus node dysfunction. Cardiac conduction disturbances (exclusively sinus bradycardia) were registered in 7% (53 of 727) patients: in 8% (37 of 451) of patients enrolled in primary center and in 6% (17 of 276) of patients enrolled in other hospitals; 95% CI: [-0.1; 0.15]. Only 0.14% of patients had symptomatic sinus bradycardia that resolved after atropine injection. Ventricular arrhythmias (exclusively Torsade de pointes tachycardia in excessive QT interval prolongation) were registered in 1.7% (12 of 727) patients: in 2% (9 of 451) of patients in primary center and in 1% (3 of 276) of patients of other hospitals; 95% CI: [-0.06; 0.08]. QTc interval prolongation to values >500 ms documented in 19% (138 of 727) of patients: in 21% (95 of 451) of patients in primary center and in 16% (43 of 276) of patients in other hospitals; 95% CI: [-0.13; 0.24].

Conclusion: In post-registration multicenter trial Refralon demonstrated good safety profile in conversion of AFib and AFl. Potential risk of TdP tachycardia mandates precautions with the use of the drug. In other hospitals Refralon did not demonstrate lower safety than in primary medical center.

Atrial Flutter Mechanism Detection Using Directed Network Mapping

Atrial flutter (AFL) is a common atrial arrhythmia typically characterized by electrical activity propagating around specific anatomical regions. It is usually treated with catheter ablation. However, the identification of rotational activities is not straightforward, and requires an intense effort during the first phase of the electrophysiological (EP) study, i.e., the mapping phase, in which an anatomical 3D model is built and electrograms (EGMs) are recorded. In this study, we modeled the electrical propagation pattern of AFL (measured during mapping) using network theory (NT), a well-known field of research from the computer science domain. The main advantage of NT is the large number of available algorithms that can efficiently analyze the network. Using directed network mapping, we employed a cycle-finding algorithm to detect all cycles in the network, resembling the main propagation pattern of AFL. The method was tested on two subjects in sinus rhythm, six in an experimental model of in-silico simulations, and 10 subjects diagnosed with AFL who underwent a catheter ablation. The algorithm correctly detected the electrical propagation of both sinus rhythm cases and in-silico simulations. Regarding the AFL cases, arrhythmia mechanisms were either totally or partially identified in most of the cases (8 out of 10), i.e., cycles around the mitral valve, tricuspid valve and figure-of-eight reentries. The other two cases presented a poor mapping quality or a major complexity related to previous ablations, large areas of fibrotic tissue, etc. Directed network mapping represents an innovative tool that showed promising results in identifying AFL mechanisms in an automatic fashion. Further investigations are needed to assess the reliability of the method in different clinical scenarios.

Association of atrial arrhythmias with thrombospondin-1 in patients with acute myocardial infarction

OBJECTIVES

Atrial remodeling is the main developmental cause of atrial arrhythmias (AA), which may induce atrial fibrillation, atrial flutter, atrial tachycardia, and frequent premature atrial beats in acute myocardial infarction (AMI) patients. Thrombospondin-1 (TSP-1) has been shown to play an important role in inflammatory and fibrotic processes, but its role in atrial arrhythmias is not well described. The purpose of this study was to investigate the role of TSP-1 in AMI patients with atrial arrhythmias.

METHODS

A total of 219 patients with AMI who underwent percutaneous coronary intervention and with no previous arrhythmias were included. TSP-1 were analyzed in plasma samples. Patients were classified into 2 groups, namely, with and without AA during the acute phase of MI. Continuous electrocardiographic monitoring was used for AA diagnosis in hospital.

RESULTS

Twenty-four patients developed AA. Patients with AA had higher TSP-1 levels (29.01 ± 25.87 μg/mL vs 18.36 ± 10.89 μg/mL, p < 0.001) than those without AA. AA patients also tended to be elderly (65.25 ± 9.98 years vs 57.47 ± 10.78 years, p < 0.001), had higher Hs-CRP (39.74 ± 43.50 mg/L vs 12.22 ± 19.25 mg/L, p < 0.001) and worse heart function. TSP-1 (OR 1.033; 95% CI 1.003-1.065, p = 0.034), Hs-CRP (OR 1.023; 95% CI 1.006-1.041, p = 0.008), age (OR 1.067; 95% CI 1.004-1.135, p = 0.038) and LVDd (OR 1.142; 95% CI 1.018-1.282, p = 0.024) emerged as independent risk factors for AA in AMI patients.

CONCLUSION

TSP-1 is a potential novel indicator of atrial arrhythmias during AMI.

Preventing atrial fibrillation by combined right isthmus ablation and cryoballoon pulmonary vein isolation in patients with typical atrial flutter: PAF-CRIOBLAF study

BACKGROUND

Although less common, typical atrial flutter shares similar pathophysiological roots with atrial fibrillation. Following successful cavo-tricuspid isthmus ablation using radiofrequency, many patients, however, develop atrial fibrillation in the mid-to-long-term. This study sought to assess whether pulmonary vein isolation conducted at the same time as cavo-tricuspid isthmus ablation would significantly modify the atrial fibrillation burden upon follow-up in patients suffering from typical atrial flutter.

METHODS

This was a multicenter randomized controlled study involving typical atrial flutter patients with history of non-predominant atrial fibrillation (1 atrial fibrillation episode only, in 67% of population) who were scheduled for cavo-tricuspid isthmus radiofrequency ablation. Patients were randomly assigned to either undergo cavo-tricuspid isthmus ablation alone or cavo-tricuspid isthmus plus pulmonary vein isolation (CTI+). Pulmonary vein isolation was performed using cryoballoon technology. An outpatient consultation with ECG and 1-week Holter monitoring was performed at 3, 6 months, 1 year, and 2 years postprocedure. The primary endpoint was atrial fibrillation recurrences lasting more than 30 s at 2 years postablation.

RESULTS

Of the patients enrolled, 36 were included in each group. At 2-year follow-up, the atrial fibrillation recurrence rate was significantly higher in the CTI vs CTI+group (25/36, 69% vs. 12/36, 33% respectively; P < .001), with similar typical atrial flutter recurrence rates. There were no differences in undesirable events, except for transient phrenic nerve palsy reported from three CTI+patients (8.3%).

CONCLUSION

Pulmonary vein isolation using cryoballoon technology was proven to significantly reduce the atrial fibrillation incidence at 2 years postcavo-tricuspid isthmus ablation.

Prospective Evaluation of a Standardized Screening for Atrial Fibrillation after Ablation of Cavotricuspid Isthmus Dependent Atrial Flutter

Aims: We aimed to prospectively investigate the effectiveness of a standardized follow-up for AF-detection after common atrial flutter (cAFL) ablation. Methods: A total of 309 patients after cAFL ablation without known AF, from 5 centers, and at least one completed, standardized follow-up at 3, 6 and 12 months, including a 24 h Holter-electrocardiogram (ECG), were included. The primary outcome was incident atrial fibrillation (AF), or atrial tachycardia (AT). Predictors were investigated by Cox proportional-hazards models. Results: The mean age was 67.9 years; 15.2% were female and the mean CHA₂DS₂-VASc (Congestive heart failure, Hypertension, Age, Diabetes, Stroke, Vascular disease, Sex category) score was 2.4 points. The great majority of patients (90.3%) were anticoagulated. Over a mean follow-up of 12.2 months with a standardized approach, AF/AT was detected in 73 patients, corresponding to 11.7% at 3 months, 18.4% at 6 months and 28.2% at 12 months of follow-up. AF was found in 64 patients, AT in 9 and both in 2 patients. Occurrence of AF was recorded in 40 (60.6%) patients by Holter-ECG and in the remaining 26 (39.4%) by clinical follow-up only. There was no difference in male versus female (p = 0.08), or in younger versus older patients (p = 0.96) for AF/AT detection. Only coronary artery disease (hazard ratio [95% confidence intervals] 1.03 [1.01–1.05], p = 0.01) was associated with the primary outcome. Conclusions: AF or AT was detected in a large proportion of cAFL patients after cavotricuspid-isthmus (CTI) ablation, using a standardized follow-up over 1 year. This standardized screening can be easily implemented with high patient acceptance. The high proportion of post-ablation AF needs to be taken into consideration when deciding on long-term oral anticoagulation.

Automated Arrhythmia Detection Based on RR Intervals

Abnormal heart rhythms, also known as arrhythmias, can be life-threatening. AFIB and AFL are examples of arrhythmia that affect a growing number of patients. This paper describes a method that can support clinicians during arrhythmia diagnosis. We propose a deep learning algorithm to discriminate AFIB, AFL, and NSR RR interval signals. The algorithm was designed with data from 4051 subjects. With 10-fold cross-validation, the algorithm achieved the following results: ACC = 99.98%, SEN = 100.00%, and SPE = 99.94%. These results are significant because they show that it is possible to automate arrhythmia detection in RR interval signals. Such a detection method makes economic sense because RR interval signals are cost-effective to measure, communicate, and process. Having such a cost-effective solution might lead to widespread long-term monitoring, which can help detecting arrhythmia earlier. Detection can lead to treatment, which improves outcomes for patients.