Excessive Atrial Ectopy and Short Atrial Runs Increase the Risk of Stroke Beyond Incident Atrial Fibrillation

Power-law properties of nocturnal arrhythmia avalanches: A novel marker for incident cardiovascular events

BACKGROUND

Bursting nonsustained cardiac arrhythmia events are a common observation during sleep.

OBJECTIVES

The purpose of this study was to investigate the hypothesis that nocturnal arrhythmia episode durations could follow a power law, whose exponent could predict long-term clinical outcomes.

METHODS

We defined "nocturnal arrhythmia avalanche" (NAA) as any instance of a drop in electrocardiographic (ECG) template-matched R-R intervals ≥30% of R-R baseline, followed by a return to 90% of baseline. We studied NAA in ECG recordings obtained from the Sleep Heart Health Study (SHHS), Osteoporotic Fractures in Men Study (MrOS) Study, and Multi-Ethnic Study of Atherosclerosis (MESA). The association of nocturnal arrhythmia durations with a power-law distribution was evaluated and the association of derived power-law exponents (α) with major adverse cardiovascular (CV) events and mortality assessed with multivariable Cox regression.

RESULTS

A total of 9176 participants were studied. NAA episodes distribution was consistent with power-law vs comparator distributions in all datasets studied (positive log likelihood ratio of power-law vs exponential in MESA: 83%; SHHS: 69%; MrOS: 81%; power-law vs log-normal in MESA: 95%; SHHS: 35%; MrOS: 64%). The NAA power-law exponent (α) showed a significant association of with adverse CV outcomes (association with CV mortality: SHHS hazard ratio 1.39 [1.07-1.79], P = .012; MrOS hazard ratio 1.42 [1.02-1.94], P = .039; association with CV events: MESA HR 3.46 [1.46-8.21], P = .005) in multivariable Cox regression, after adjusting for conventional CV risk factors and nocturnal ectopic rate.

CONCLUSION

The NAA power-law exponent is a reproducible, predictive marker for incident CV events and mortality.

Excessive Supraventricular Ectopic Activity in Patients With Acute Ischemic Stroke Is Associated With Atrial Fibrillation Detection Within 24 Months After Stroke: A Predefined Analysis of the MonDAFIS Study

BACKGROUND

Excessive supraventricular ectopic activity (ESVEA) is regarded as a risk marker for later atrial fibrillation (AF) detection.

METHODS AND RESULTS

The investigator-initiated, prospective, open, multicenter MonDAFIS (Impact of Standardized Monitoring for Detection of Atrial Fibrillation in Ischemic Stroke) study randomized 3465 patients with acute ischemic stroke without known AF 1:1 to usual diagnostic procedures for AF detection or additive Holter monitoring in hospital for up to 7 days, analyzed in a core laboratory. Secondary study objectives include the comparison of recurrent stroke, myocardial infarction, major bleeding, and all-cause death within 24 months in patients with ESVEA (defined as ectopic supraventricular beats ≥480/day or atrial runs of 10-29 seconds or both) versus patients with newly diagnosed AF versus patients without ESVEA or AF (non-ESVEA/AF), randomized to the intervention group. Overall, 1435 (84.8%) of 1714 patients randomized to the intervention group had analyzable study ECG monitoring of at least 48 hours' duration within the first 72 hours of monitoring. ESVEA was detected in 363 (25.3%) patients, while AF was first detected in 48 (3.3%) patients. Within 24 months, AF was newly detected in 67 (18.5%) patients with ESVEA versus 60 (5.9%) patients without ESVEA/AF- (P<0.001). The composite outcome at 24 months was not different between patients with ESVEA and patients without ESVEA/AF (15.2% versus 12.6%; P=0.242). All-cause death was numerically higher in patients with ESVEA (6.6% versus 3.2%), but failed statistical significance (P=0.433) in multivariate analysis (including age, heart failure, stroke severity, and creatinine at baseline).

CONCLUSIONS

ESVEA in the acute phase of ischemic stroke or transient ischemic attack is associated with AF detection during follow-up and therefore may be used to select patients for prolonged ECG monitoring.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02204267.

Predictors of paroxysmal atrial fibrillation in patients with a cryptogenic stroke: Selecting patients for long-term rhythm monitoring

BACKGROUND

After a cryptogenic stroke, patients often will require prolonged cardiac monitoring; however, the subset of patients who would benefit from long-term rhythm monitoring is not clearly defined.

OBJECTIVE

The purpose of this study was to create a risk score by identifying significant predictors of atrial fibrillation (AF) using age, sex, comorbidities, baseline 12-lead electrocardiogram, short-term rhythm monitoring, and echocardiographic data and to compare it to previously published risk scores.

METHODS

Patients admitted to Montefiore Medical Center between May 2017 and June 2022 with a primary diagnosis of cryptogenic stroke or transient ischemic attack who underwent long-term rhythm monitoring with an implantable cardiac monitor were retrospectively analyzed.

RESULTS

Variables positively associated with a diagnosis of clinically significant AF include age (P <.001), race (P = .022), diabetes status (P = .026), chronic obstructive pulmonary disease status (P = .012), presence of atrial runs (P = .003), number of atrial runs per 24 hours (P <.001), total number of atrial run beats per 24 hours (P <.001), number of beats in the longest atrial run (P <.001), left atrial enlargement (P = .007), and at least mild mitral regurgitation (P = .009). We created a risk stratification score for our population, termed the ACL score. The ACL score demonstrated superiority to the CHA2DS2-VASc score and comparability to the C2HEST score for predicting device-detected AF.

CONCLUSION

The ACL score enables clinicians to better predict which patients are more likely to be diagnosed with device-detected AF after a cryptogenic stroke.

Prognoses and risk stratification of thrombus-associated events in heart failure patients without atrial fibrillation

AIMS

We aim to assess the risk of thrombus-associated events (TAE) in patients with heart failure (HF) without atrial fibrillation (AF) and develop an effective scoring system for a risk stratification model.

METHODS AND RESULTS

This retrospective study included 450 patients (median age 64.0 years, interquartile range [55.0, 75.0]; 31.6% women) hospitalized for HF without AF and atrial flutter, but with a left ventricular ejection fraction (LVEF) ≤ 55% and New York Heart Association (NYHA) functional class of III-IV. A median follow-up of 47 months was conducted. In the present study, TAE during follow-up was independently associated with both all-cause death [hazard ratio (HR) 1.756, 95% confidence interval (CI) 1.324-2.328, P < 0.001] and readmission for HF (HR 1.574, 95% CI 1.122-2.208, P = 0.009) after adjustment for covariates. Hypertension (HR 1.573, 95% CI 1.018-2.429, P = 0.041), atrial arrhythmia excluding AF (AAexAF) (HR 2.041, 95% CI 1.066-3.908, P = 0.031), previous ischaemic stroke (HR 2.469, 95% CI 1.576-3.869, P < 0.001), and vascular disease (HR 1.658, 95% CI 1.074-2.562, P = 0.023) were independently associated with TAE. Age (HR 1.021, 95% CI 1.008-1.033, P = 0.001), previous ischaemic stroke (HR 1.685, 95% CI 1.248-2.274, P = 0.001), LVEF ([10, 25] vs. [40, 55]) HR 1.925, 95% CI 1.311-2.826, P = 0.001; (25, 40] vs. (40, 55] HR 1.084, 95% CI 0.825-1.424, P = 0.563), and creatinine clearance rate (Ccr) (HR 0.991, 95% CI 0.986-0.996, P = 0.001) were independently associated with composite events of TAE and death (TAE-D). CHA2DS2VASc modestly predicted 5-year TAE [area under the receiver operating characteristic curves (AUC) 0.660, P < 0.001 compared with 0.5] and TAE-D (AUC 0.639, P < 0.001 compared with 0.5). (C)ACE, formed by incorporating AAexAF, LVEF, and Ccr into CHA2DS2VASc, had higher AUC for predicting 5-year TAE (0.694 vs. 0.660, P = 0.018) and TAE-D (0.708 vs. 0.639, P < 0.001) compared with CHA2DS2VASc. In patients with HF with reduced ejection fraction (HFrEF), (C)ACE and (C)ACEN [formed by incorporating NYHA into (C)ACE] had higher AUC compared with CHA2DS2VASc in predicting 5-year TAE (0.700 and 0.707 vs. 0.649, P = 0.013 and 0.030, respectively) and TAE-D (0.712 and 0.713 vs. 0.622, P < 0.001 and <0.001, respectively). The AUC did not improve statistically from (C)ACE to (C)ACEN (0.700 vs. 0.707, P = 0.600 for TAE; 0.712 vs. 0.713, P = 0.917 for TAE-D).

CONCLUSIONS

In HF without AF, TAE during follow-up was associated with adverse prognoses. The independent risk factors of TAE or TAE-D improved CHA2DS2-VASc predictive ability, especially in patients with HFrEF. Our findings provide new evidence for TAE risk stratification in HF without AF, potentially guiding prophylactic anticoagulation.

Performance of Ambulatory Electrocardiographic Data for Prediction of Stroke and Heart Failure Events

Background

Despite clear associations between arrhythmia burden and cardiovascular risk, clinical risk scores that predict cardiovascular events do not incorporate individual-level arrhythmia characteristics from long-term continuous monitoring (LTCM).

Objectives

This study evaluated the performance of risk models that use data from LTCM and patient claims for prediction of heart failure (HF) and ischemic stroke.

Methods

We retrospectively analyzed features extracted from up to 14 days of LTCM electrocardiogram (ECG) data linked to patient-level claims data for 320,974 Medicare beneficiaries who underwent ZioXT ambulatory monitoring. We created predictive models for HF hospitalization, stroke hospitalization, and new-onset HF within 1 year using LASSO Cox regression for variable selection among ambulatory ECG variables and components of the CHA2DS2-VASc score.

Results

A model that included components of the CHA2DS2-VASc and all ambulatory ECG variables had greater discrimination for HF hospitalization (C-statistic 0.85, 95% CI: 0.84-0.86) than the CHA2DS2-VASc (C-statistic 0.73, 95% CI: 0.72-0.74), but performed similarly to the CHA2DS2-VASc for prediction of stroke hospitalization (C-statistic 0.75 [95% CI: 0.74-0.77] vs 0.71 [95% CI: 0.70-0.72], respectively). Atrial fibrillation was associated with greater risk in the most predictive models (HF hospitalization, HR: 1.53 [95% CI: 1.35-1.72]; stroke hospitalization, HR: 1.58 [95% CI: 1.30-1.93]), and premature ventricular couplets were associated with greater risk of HF hospitalization (HR: 1.54, 95% CI: 1.43-1.65).

Conclusions

The CHA2DS2-VASc performed modestly for prediction of stroke and HF events; predictive ability improved significantly with addition of LTCM ECG covariates. The presence of atrial fibrillation and ventricular ectopy on 14-day LTCM were strongly associated with HF events.

Association between blood pressure levels and premature atrial contractions in patients with hypertension

BACKGROUND

High blood pressure (BP) induces left atrial structural and functional remodeling that increases susceptibility to atrial arrhythmia. We hypothesized that lower systolic BP (SBP) levels are associated with a lower prevalence of premature atrial contractions (PACs) in patients with hypertension.

METHODS

This analysis included 4,697 participants (mean age 62±13.1 years, 50% women, 25.6% blacks) with hypertension from the Third National Health and Nutrition Examination Survey who did not have a prior history of cardiovascular disease (CVD). Multivariable logistic regression was used to examine the cross-sectional association between SBP and prevalence of PACs ascertained from 12-lead resting electrocardiograms. Multivariable Cox proportional hazard analysis was used to examine the association between baseline PACs and CVD mortality.

RESULTS

Approximately 1.6% (n=74) of participants had baseline PACs. Patients with SBP ≤140 mmHg had a lower prevalence of PACs than those with SBP ≥140 mmHg (1.1% vs. 1.9%, p-value=0.01). In a multivariable logistic regression model, each 10 mmHg decrease in SBP was associated with a 12% lower odds of PACs (OR (95%CI): 0.88 (0.77-0.99)). During 14 years of follow-up, 645 CVD deaths occurred. In a multivariable-adjusted Cox model, presence of PACs was associated with a 78% increased risk of CVD mortality (HR (95%CI): 1.78 (1.23-2.60)).

CONCLUSIONS

In patients with hypertension, lower SBP levels are associated with a lower prevalence of PACs, and presence of PACs is associated with a higher risk of CVD mortality risk. These findings highlight the potential role of BP lowering in the management of cardiac arrhythmias.

Atrial cardiomyopathy revisited-evolution of a concept: a clinical consensus statement of the European Heart Rhythm Association (EHRA) of the ESC, the Heart Rhythm Society (HRS), the Asian Pacific Heart Rhythm Society (APHRS), and the Latin American Heart Rhythm Society (LAHRS)

AIMS

The concept of "atrial cardiomyopathy" (AtCM) had been percolating through the literature since its first mention in 1972. Since then, publications using the term were sporadic until the decision was made to convene an expert working group with representation from four multinational arrhythmia organizations to prepare a consensus document on atrial cardiomyopathy in 2016 (EHRA/HRS/APHRS/SOLAECE expert consensus on atrial cardiomyopathies: definition, characterization, and clinical implication). Subsequently, publications on AtCM have increased progressively.

METHODS AND RESULTS

The present consensus document elaborates the 2016 AtCM document further to implement a simple AtCM staging system (AtCM stages 1-3) by integrating biomarkers, atrial geometry, and electrophysiological changes. However, the proposed AtCM staging needs clinical validation. Importantly, it is clearly stated that the presence of AtCM might serve as a substrate for the development of atrial fibrillation (AF) and AF may accelerates AtCM substantially, but AtCM per se needs to be viewed as a separate entity.

CONCLUSION

Thus, the present document serves as a clinical consensus statement of the European Heart Rhythm Association (EHRA) of the ESC, the Heart Rhythm Society (HRS), the Asian Pacific Heart Rhythm Society (APHRS), and the Latin American Heart Rhythm Society (LAHRS) to contribute to the evolution of the AtCM concept.

Diagnostic reliability of monitoring for premature atrial and ventricular complexes

AIMS

Short-term ambulatory electrocardiogram (ECG) monitoring is often used to assess premature atrial complex (PAC) and premature ventricular complex (PVC) frequency, but the diagnostic reliability is unknown. The objective of this study was to study the day-to-day variability of PAC and PVC frequency.

METHODS AND RESULTS

We used 14-day full-disclosure mobile cardiac telemetry recordings without atrial fibrillation in 8245 US patients aged 17-103 years to calculate the diagnostic reliability of shorter ambulatory ECG recordings compared with 14-day averages. Over 14 days, 1853 patients had ≥500 PACs/day, 410 patients had ≥5000 PACs/day, and 197 patients had ≥10 000 PACs/day; 1640 patients had ≥500 PVCs/day, 354 patients had ≥5000 PVCs/day, and 175 patients had ≥10 000 PVCs/day. After 3 days, the estimated daily PAC frequency differed by ≥50% from the 14-day mean in 25% of patients; for PVCs, the corresponding duration was 7 days. Ten days of monitoring were needed to estimate PAC and PVC frequency within ±20% of the overall 14-day frequency in 80% of patients. For daily PAC and PVC frequencies ≥10 000, single-day estimation had a specificity of 99.3% [95% confidence interval (CI) 99.1-99.5] at a sensitivity of 76.6 (95% CI 70.1-80.4%) for PACs and a 99.6% (95% CI 99.4-99.7%) specificity at 79.4 (95% CI 72.7-85.2) sensitivity for PVCs. After 7 days, the sensitivity increased to 88.8% (95% CI 83.6-92.9) for PACs and 86.9% (95% CI 80.9-91.5%) for PVCs.

CONCLUSION

While there is substantial daily variability across most PAC and PVC levels, findings of ≥10 000 PACs or PVCs are highly specific and do not need to be confirmed with longer recordings.

A gray zone: Role of transesophageal echocardiography before atrial tachycardia catheter ablation

INTRODUCTION

There is a lack of studies in the literature directly investigating the relationship between atrial tachycardia (AT) and left atrial (LA)/left atrial appendage (LAA) thrombus, and current guidelines do not provide strong recommendations regarding the use of transesophageal echocardiography (TEE) before AT catheter ablation. This study aims to elucidate the relationship between AT and the presence of LA/LAA thrombus and contribute to the literature on the use of TEE before AT catheter ablation.

METHODS

This single-center retrospective observational study screened patients who underwent TEE between February 10, 2019, and February 10, 2023. Patients were assigned to the AT patient and control groups. TEE was conducted to exclude thrombus in the AT ablation group. The control group included patients who underwent TEE for interatrial septum evaluation and had LA imaging during TEE but did not have atrial arrhythmia. To mitigate bias between the AT patient group and the control group, they were randomized 1:1 using propensity-score matching (PSM). Following randomization, each group consisted of 49 patients.

RESULTS

All analyses were conducted after PSM. There were no statistically significant differences between the AT patient and control groups in terms of baseline clinical characteristics and echocardiographic features. Additionally, no significant differences were found between the blood viscosities calculated at low and high shear rates in both groups. The study revealed a significant difference between the two groups in the presence of LA spontaneous echo contrast (SEC) (24.5% in AT group vs 0% in Control group, p = .001), but not in the presence of thrombi (8.2% in AT group vs 0% in Control group, p = .117).

CONCLUSION

Compared to the control group, the presence of SEC was significantly higher in the AT patient group. The increased frequency of SEC in AT patients suggests the hypothesis that AT may contribute to LA stasis. The routine use of TEE before AT catheter ablation remains controversial, despite the presence of LA thrombus and SEC in the AT patient group. The clinical assessment of thrombus presence before the procedure must be conducted on a patient-specific basis.

High premature atrial complex burden and risk of renal function decline

Background

Atrial arrhythmia, particularly atrial fibrillation (AF), is known to be associated with renal function decline and increased risk of end-stage kidney disease. In recent years, premature atrial complexes (PACs) as subclinical arrhythmia have been proposed to be a marker of atrial cardiomyopathy and associated with poor clinical outcomes. However, the relationship between excessive daily PAC burden and renal outcomes remains unexplored.

Methods

This retrospective, all-comers cohort study analyzed 30 488 consecutive Holter monitoring records obtained from a validated Holter databank at a referral medical center in Taiwan between 2011 and 2018. After exclusion, 10 981 patients were categorized into three groups: high daily PAC burden (≥100 beats per day), low PAC burden (<100 beats per day) and the AF group. We used parallel propensity score matching to balance confounding factors between groups. The primary study interest was major adverse kidney events, including an estimated glomerular filtration rate (eGFR) decline of 40%, eGFR <15 mL/min/1.73 m2 or the initiation of hemodialysis.

Results

After a mean follow-up of 4.07 ± 3.03 years, patients with high PAC burden had a 1.24-fold higher incidence of major adverse kidney events compared with the low PAC burden group [95% confidence interval (CI) 1.03-1.50]. The risk of major adverse kidney events was similar between patients with AF and those with high PAC burden [adjusted hazard ratio (HR) 1.05, 95% CI 0.87-1.25], but significantly higher in the AF group than in the low PAC burden group (adjusted HR 1.29, 95% CI 1.07-1.56).

Conclusion

Excessive daily PAC burden is associated with a higher risk of major adverse kidney events and has a comparable impact as AF.

Atrial Fibrillation, Atrial Myopathy, and Thromboembolism: The Additive Value of Echocardiography and Possible New Horizons for Risk Stratification

Atrial fibrillation (AF) is the most common cardiac sustained arrhythmia, and it is associated with increased stroke and dementia risk. While the established paradigm attributes these complications to blood stasis within the atria and subsequent thrombus formation with cerebral embolization, recent evidence suggests that atrial myopathy (AM) may play a key role. AM is characterized by structural and functional abnormalities of the atria, and can occur with or without AF. Moving beyond classifications based solely on episode duration, the 4S-AF characterization has offered a more comprehensive approach, incorporating patient's stroke risk, symptom severity, AF burden, and substrate assessment (including AM) for tailored treatment decisions. The "ABC" pathway emphasizes anticoagulation, symptom control, and cardiovascular risk modification and emerging evidence suggests broader benefits of early rhythm control strategies, potentially reducing stroke and dementia risk and improving clinical outcomes. However, a better integration of AM assessment into the current framework holds promise for further personalizing AF management and optimizing patient outcomes. This review explores the emerging concept of AM and its potential role as a risk factor for stroke and dementia and in AF patients' management strategies, highlighting the limitations of current risk stratification methods, like the CHA2DS2-VASc score. Echocardiography, particularly left atrial (LA) strain analysis, has shown to be a promising non-invasive tool for AM evaluation and recent studies suggest that LA strain analysis may be a more sensitive risk stratifier for thromboembolic events than AF itself, with some studies showing a stronger association between LA strain and thromboembolic events compared to traditional risk factors. Integrating it into routine clinical practice could improve patient management and targeted therapies for AF and potentially other thromboembolic events. Future studies are needed to explore the efficacy and safety of anticoagulation in AM patients with and without AF and to refine the diagnostic criteria for AM.

Natural history of cardiac involvement in myotonic dystrophy type 1 - Emphasis on the need for lifelong follow-up

BACKGROUND

Cardiac involvement represents a major cause of morbidity and mortality in patients with myotonic dystrophy type 1 (DM1) and prevention of sudden cardiac death (SCD) is a central part of patient care. We investigated the natural history of cardiac involvement in patients with DM1 to provide an evidence-based foundation for adjustment of follow-up protocols.

METHODS

Patients with genetically confirmed DM1 were identified. Data on patient characteristics, performed investigations (12 lead ECG, Holter monitoring and echocardiography), and clinical outcomes were retrospectively collected from electronic health records.

RESULTS

We included 195 patients (52% men) with a mean age at baseline evaluation of 41 years (range 14-79). The overall prevalence of cardiac involvement increased from 42% to 66% after a median follow-up of 10.5 years. There was a male predominance for cardiac involvement at end of follow-up (74 vs. 44%, p < 0.001). The most common types of cardiac involvement were conduction abnormalities (48%), arrhythmias (35%), and left ventricular systolic dysfunction (21%). Only 17% of patients reported cardiac symptoms. The standard 12‑lead ECG was the most sensitive diagnostic modality and documented cardiac involvement in 24% at baseline and in 49% at latest follow-up. However, addition of Holter monitoring and echocardiography significantly increased the diagnostic yield with 18 and 13% points at baseline and latest follow-up, respectively. Despite surveillance 35 patients (18%) died during follow-up; seven due to SCD.

CONCLUSIONS

In patients with DM1 cardiac involvement was highly prevalent and developed during follow-up. These findings justify lifelong follow-up with ECG, Holter, and echocardiography.

CLINICAL PERSPECTIVE

What is new? What are the clinical implications?

Detection of Non-Sustained Supraventricular Tachycardia in Atrial Fibrillation Screening

OBJECTIVE

Non-sustained supraventricular tachycardia (nsSVT) is associated with a higher risk of developing atrial fibrillation (AF), and, therefore, detection of nsSVT can improve AF screening efficiency. However, the detection is challenged by the lower signal quality of ECGs recorded using handheld devices and the presence of ectopic beats which may mimic the rhythm characteristics of nsSVT.

METHODS

The present study introduces a new nsSVT detector for use in single-lead, 30-s ECGs, based on the assumption that beats in an nsSVT episode exhibits similar morphology, implying that episodes with beats of deviating morphology, either due to ectopic beats or noise/artifacts, are excluded. A support vector machine is used to classify successive 5-beat sequences in a sliding window with respect to similar morphology. Due to the lack of adequate training data, the classifier is trained using simulated ECGs with varying signal-to-noise ratio. In a subsequent step, a set of rhythm criteria is applied to similar beat sequences to ensure that episode duration and heart rate is acceptable.

RESULTS

The performance of the proposed detector is evaluated using the StrokeStop II database, resulting in sensitivity, specificity, and positive predictive value of 84.6%, 99.4%, and 18.5%, respectively.

CONCLUSION

The results show that a significant reduction in expert review burden (factor of 6) can be achieved using the proposed detector.Clinical and Translational Impact: The reduction in the expert review burden shows that nsSVT detection in AF screening can be made considerably more efficiently.

Atrial myopathy

This paper delves into the progressive concept of atrial myopathy, shedding light on its development and its impact on atrial characteristics. It extensively explores the intricate connections between atrial myopathy, atrial fibrillation (AF), and strokes. Researchers have sought additional contributors to AF-related strokes due to the absence of a clear timing correlation between paroxysmal AF episodes and strokes in patients with cardiac implantable electronic devices. Through various animal models and human investigations, a close interrelation among aging, inflammation, oxidative stress, and stretching mechanisms has been identified. These mechanisms contribute to fibrosis, alterations in electrical properties, autonomic remodeling, and a heightened pro-thrombotic state. These interconnected factors establish a detrimental cycle, exacerbating atrial myopathy and elevating the risk of sustained AF and strokes. By emphasizing the significance of atrial myopathy and the risk of strokes that are distinct from AF, the paper also discusses methods for identifying patients with atrial myopathy. Moreover, it proposes an approach to incorporate the concept of atrial myopathy into clinical practice to guide anticoagulation decisions in individuals with AF.

Frequent Premature Atrial Contractions Lead to Adverse Atrial Remodeling and Atrial Fibrillation in a Swine Model

BACKGROUND

Frequent premature atrial complexes (PACs) are associated with future incident atrial fibrillation (AF), but whether PACs contribute to development of AF through adverse atrial remodeling has not been studied. This study aimed to explore the effect of frequent PACs from different sites on atrial remodeling in a swine model.

METHODS

Forty swine underwent baseline electrophysiologic studies and echocardiography followed by pacemaker implantations and paced PACs (50% burden) at 250-ms coupling intervals for 16 weeks in 4 groups: (1) lateral left atrium (LA) PACs by the coronary sinus (Lat-PAC; n=10), (2) interatrial septal PACs (Sep-PAC; n=10), (3) regular LA pacing at 130 beats/min (Reg-130; n=10), and (4) controls without PACs (n=10). At the final study, repeat studies were performed, followed by tissue histology and molecular analyses focusing on fibrotic pathways.

RESULTS

Lat-PACs were associated with a longer P-wave duration (93.0±9.0 versus 74.2±8.2 and 58.8±7.6 ms; P<0.001) and greater echocardiographic mechanical dyssynchrony (57.5±11.6 versus 35.7±13.0 and 24.4±11.1 ms; P<0.001) compared with Sep-PACs and controls, respectively. After 16 weeks, Lat-PACs led to slower LA conduction velocity (1.1±0.2 versus 1.3±0.2 [Sep-PAC] versus 1.3±0.1 [Reg-130] versus 1.5±0.2 [controls] m/s; P<0.001) without significant change in atrial ERP. The Lat-PAC group had a significantly increased percentage of LA fibrosis and upregulated levels of extracellular matrix proteins (lysyl oxidase and collagen 1 and 8), as well as TGF-β1 (transforming growth factor-β1) signaling proteins (latent and monomer TGF-β1 and phosphorylation/total ratio of SMAD2/3; P<0.05). The Lat-PAC group had the longest inducible AF duration (terminal to baseline: 131 [interquartile range 30, 192] seconds versus 16 [6, 26] seconds [Sep-PAC] versus 22 [11, 64] seconds [Reg-130] versus -1 [-16, 7] seconds [controls]; P<0.001).

CONCLUSIONS

In this swine model, frequent PACs resulted in adverse atrial structural remodeling with a heightened propensity to AF. PACs originating from the lateral LA produced greater atrial remodeling and longer induced AF duration than the septal-origin PACs. These data provide evidence that frequent PACs can cause adverse atrial remodeling as well as AF, and that the location of ectopic PACs may be clinically meaningful.

The Brain-Heart Axis: Neuroinflammatory Interactions in Cardiovascular Disease

PURPOSE OF REVIEW

The role of neuroimmune modulation and inflammation in cardiovascular disease has been historically underappreciated. Physiological connections between the heart and brain, termed the heart-brain axis (HBA), are bidirectional, occur through a complex network of autonomic nerves/hormones and cytokines, and play important roles in common disorders.

RECENT FINDINGS

At the molecular level, advances in the past two decades reveal complex crosstalk mediated by the sympathetic and parasympathetic nervous systems, the renin-angiotensin aldosterone and hypothalamus-pituitary axes, microRNA, and cytokines. Afferent pathways amplify proinflammatory signals via the hypothalamus and brainstem to the periphery, promoting neurogenic inflammation. At the organ level, while stress-mediated cardiomyopathy is the prototypical disorder of the HBA, cardiac dysfunction can result from a myriad of neurologic insults including stroke and spinal injury. Atrial fibrillation is not necessarily a causative factor for cardioembolic stroke, but a manifestation of an abnormal atrial substrate, which can lead to the development of stroke independent of AF. Central and peripheral neurogenic proinflammatory factors have major roles in the HBA, manifesting as complex bi-directional relationships in common conditions such as stroke, arrhythmia, and cardiomyopathy.

ECG Modeling for Simulation of Arrhythmias in Time-Varying Conditions

The present article proposes an ECG simulator that advances modeling of arrhythmias and noise by introducing time-varying signal characteristics. The simulator is built around a discrete-time Markov chain model for simulating atrial and ventricular arrhythmias of particular relevance when analyzing atrial fibrillation (AF). Each state is associated with statistical information on episode duration and heartbeat characteristics. Statistical, time-varying modeling of muscle noise, motion artifacts, and the influence of respiration is introduced to increase the complexity of simulated ECGs, making the simulator well suited for data augmentation in machine learning. Modeling of how the PQ and QT intervals depend on heart rate is also introduced. The realism of simulated ECGs is assessed by three experienced doctors, showing that simulated ECGs are difficult to distinguish from real ECGs. Simulator usefulness is illustrated in terms of AF detection performance when either simulated or real ECGs are used to train a neural network for signal quality control. The results show that both types of training lead to similar performance.

Can 24 h of ambulatory ECG be used to triage patients to extended monitoring?

BACKGROUND

Access to long-term ambulatory recording to detect atrial fibrillation (AF) is limited for economical and practical reasons. We aimed to determine whether 24 h ECG (24hECG) data can predict AF detection on extended cardiac monitoring.

METHODS

We included all US patients from 2020, aged 17-100 years, who were monitored for 2-30 days using the PocketECG device (MEDICALgorithmics), without AF ≥30 s on the first day (n = 18,220, mean age 64.4 years, 42.4% male). The population was randomly split into equal training and testing datasets. A Lasso model was used to predict AF episodes ≥30 s occurring on days 2-30.

RESULTS

The final model included maximum heart rate, number of premature atrial complexes (PACs), fastest rate during PAC couplets and triplets, fastest rate during premature ventricular couplets and number of ventricular tachycardia runs ≥4 beats, and had good discrimination (ROC statistic 0.7497, 95% CI 0.7336-0.7659) in the testing dataset. Inclusion of age and sex did not improve discrimination. A model based only on age and sex had substantially poorer discrimination, ROC statistic 0.6542 (95% CI 0.6364-0.6720). The prevalence of observed AF in the testing dataset increased by quintile of predicted risk: 0.4% in Q1, 2.7% in Q2, 6.2% in Q3, 11.4% in Q4, and 15.9% in Q5. In Q1, the negative predictive value for AF was 99.6%.

CONCLUSION

By using 24hECG data, long-term monitoring for AF can safely be avoided in 20% of an unselected patient population whereas an overall risk of 9% in the remaining 80% of the population warrants repeated or extended monitoring.

Markers of Atrial Myopathy in the General Population: Prevalence, Predictors, and Inter-Relations

BACKGROUND

Atrial myopathy refers to structural and functional cardiac abnormalities associated with atrial fibrillation and stroke, but appropriate diagnostic criteria are lacking.

OBJECTIVES

This study aimed to assess prevalence, clinical correlates, and overlap between potential atrial myopathy markers.

METHODS

The population-based SCAPIS (Swedish CArdioPulmonary bioImage Study) prospectively included 6,013 subjects without atrial fibrillation with 24-hour electrocardiograms. Resting electrocardiograms measuring P-wave indices were collected at 1 screening site (n = 1,201), and a random sample (n = 385) had echocardiographic left atrial volume index (LAVi). Atrial myopathy markers were defined as ≥500 premature atrial complexes/24 h, LAVi ≥34 mL/m2, P-wave duration >120 milliseconds, or P-wave terminal force in V1 >4,000 ms·s. Clinical correlates included age, sex, body mass index, height, smoking, physical activity, coronary artery disease, diabetes, systolic blood pressure, antihypertensive medication, and low education.

RESULTS

Atrial myopathy was common; 42% of the sample with all diagnostic modalities available had ≥1 atrial myopathy marker, but only 9% had 2 and 0.3% had ≥3. Only P-wave duration and LAVi were correlated (ρ = 0.10; P = 0.04). Clinical correlates of premature atrial complexes, P-wave indices, and LAVi differed; current smoking (34% increase; P < 0.001), systolic blood pressure (4%/mm Hg increase; P = 0.01), diabetes (35% increase; P = 0.001), and coronary artery disease (71% increase; P = 0.003) were associated with premature atrial complexes, physical activity ≥2 h/wk was associated with increased LAVi (β-coefficient = 3.1; P < 0.0001) and body mass index was associated with P-wave duration (β-coefficient = 0.4/kg/m2; P < 0.0001).

CONCLUSIONS

In the general population, indirect markers of atrial myopathy are common but only weakly correlated, and their risk factor patterns are different. More studies are needed to accurately identify individuals with atrial myopathy with diagnostic methods.

Atrial cardiomyopathy: An entity of emerging interest in the clinical setting

Since 1995, the concept of atrial cardiomyopathy (ACM) has been associated with myocardial fibrosis. Despite a consensus document in 2016, ACM's definition primarily relies on histopathological findings. The focus on diagnostic criteria for ACM is driven by the potential link to thromboembolic events even independently on atrial fibrillation (AF). The complexity of the mutual relationships between ACM and AF makes difficult any assessment of the thromboembolic risk associated to ACM per se. ACM's thrombogenicity is a multifaceted clinical phenomenon involving electrical, functional, and structural modifications. Factors such as cardiovascular risk factors (e.g., hypertension), common cardiac comorbidities (e.g., heart failure), and extracardiac conditions (e.g., neuromuscular disorders) can promote atrial derangement, triggering atrial fibrillation (AF) and increasing the risk of thromboembolic events. Several diagnostic methods are available to detect the key features of ACM, including electrical changes assessed by surface and intracavitary ECG, and structural and functional alterations evaluated through echocardiography and cardiac magnetic resonance (CMR). These methods can be complemented by electro-anatomical mapping (EAM) to enhance the accuracy of myocardial tissue characterization and assessment of atrial fibrosis. Although certain clinical conditions (e.g., atrial high-rate episodes, AHREs; embolic stroke of undetermined source, ESUS) often exhibit atrial alterations in their thromboembolic presentations, recent randomized trials have failed to demonstrate the benefits of oral anticoagulation in patients with ACM without AF. However, ACM constitutes the substrate for the development of AF, as proposed in the AF European guidelines under the 4S-AF scheme. This review emphasizes the lack of a diagnostic gold standard and the need for clinical criteria for ACM, aiming to better understand the potential therapeutic implications of atrial structural and functional derangements, even in the absence of clinical evidence of AF.

Atrial Cardiomyopathy in Valvular Heart Disease: From Molecular Biology to Clinical Perspectives

This review discusses the evolving topic of atrial cardiomyopathy concerning valvular heart disease. The pathogenesis of atrial cardiomyopathy involves multiple factors, such as valvular disease leading to atrial structural and functional remodeling due to pressure and volume overload. Atrial enlargement and dysfunction can trigger atrial tachyarrhythmia. The complex interaction between valvular disease and atrial cardiomyopathy creates a vicious cycle of aggravating atrial enlargement, dysfunction, and valvular disease severity. Furthermore, atrial remodeling and arrhythmia can predispose to atrial thrombus formation and stroke. The underlying pathomechanism of atrial myopathy involves molecular, cellular, and subcellular alterations resulting in chronic inflammation, atrial fibrosis, and electrophysiological changes. Atrial dysfunction has emerged as an essential determinant of outcomes in valvular disease and heart failure. Despite its predictive value, the detection of atrial fibrosis and dysfunction is challenging and is not included in the clinical routine. Transthoracic echocardiography and cardiac magnetic resonance imaging are the main diagnostic tools for atrial cardiomyopathy. Recently published data have revealed that both left atrial volumes and functional parameters are independent predictors of cardiovascular events in valvular disease. The integration of atrial function assessment in clinical practice might help in early cardiovascular risk estimation, promoting early therapeutic intervention in valvular disease.

Myocardial injury in patients with acute ischemic stroke detected by cardiovascular magnetic resonance imaging

BACKGROUND

Patients with acute ischemic stroke (AIS) are at high risk of adverse cardiovascular events. Until now, the burden of myocardial injury derived from cardiovascular magnetic resonance imaging (CMR) has not been established in this population.

METHODS

Patients with AIS underwent CMR at 3 Tesla within 120 h after the index stroke as part of a prospective, single-center study. Patients with persistent atrial fibrillation were excluded. Morphology and function of both cardiac chambers and atria were assessed applying SSFP cine. Myocardial tissue differentiation was based on native and contrast-enhanced imaging including late gadolinium enhancement (LGE) after 0.15 mmol/kg gadobutrol for focal fibrosis and parametric T2- and T1-mapping for diffuse findings. To detect myocardial deformation global longitudinal (GLS), circumferential (GCS) and radial (GRS) strain was measured applying feature tracking. Cardiac troponin was measured using a high-sensitivity assay (99th percentile upper reference limit 14 ng/L). T2 mapping values were compared with 20 healthy volunteers.

RESULTS

CMR with contrast media was successfully performed in 92 of 115 patients (mean age 74 years, 40% female, known myocardial infarction 6%). Focal myocardial fibrosis (LGE) was detected in 31 of 92 patients (34%) of whom 23/31 (74%) showed an ischemic pattern. Patients with LGE were more likely to have diabetes, prior myocardial infarction, prior ischemic stroke, and to have elevated troponin levels compared to those without. Presence of LGE was accompanied by diffuse fibrosis (increased T1 native values) even in remote cardiac areas as well as reduced global radial, circumferential and longitudinal strain values. In 14/31 (45%) of all patients with LGE increased T2-mapping values were detectable.

CONCLUSIONS

More than one-third of patients with AIS have evidence of focal myocardial fibrosis on CMR. Nearly half of these changes may have acute or subacute onset. These findings are accompanied by diffuse myocardial changes and reduced myocardial deformation. Further studies, ideally with serial CMR measurements during follow-up, are required to establish the impact of these findings on long-term prognosis after AIS.

Association of Left Atrial Strain With Ischemic Stroke Risk in Older Adults

Importance

The risk of ischemic stroke is higher among patients with left atrial (LA) enlargement. Left atrial strain (LAε) and LA strain rate (LASR) may indicate LA dysfunction when LA volumes are still normal. The association of LAε with incident ischemic stroke in the general population is not well established.

Objective

To investigate whether LAε and LASR are associated with new-onset ischemic stroke among older adults.

Design

The Cardiovascular Abnormalities and Brain Lesions study was conducted from September 29, 2005, to July 6, 2010, to investigate cardiovascular factors associated with subclinical cerebrovascular disease. A total of 806 participants in the Northern Manhattan Study who were aged 55 years or older without history of prior stroke or atrial fibrillation (AF) were included, and annual follow-up telephone interviews were completed May 22, 2022. Statistical analysis was performed from June through November 2022.

Exposures

Left atrial strain and LASR were assessed by speckle-tracking echocardiography. Global peak positive longitudinal LAε and positive longitudinal LASR during ventricular systole, global peak negative longitudinal LASR during early ventricular diastole, and global peak negative longitudinal LASR during LA contraction were measured. Brain magnetic resonance imaging was used to detect silent brain infarcts and white matter hyperintensities at baseline.

Main Outcomes and Measures

Risk analysis with cause-specific Cox proportional hazards regression modeling was used to assess the association of positive longitudinal LAε and positive longitudinal LASR with incident ischemic stroke, adjusting for other stroke risk factors, including incident AF.

Results

The study included 806 participants (501 women [62.2%]) with a mean (SD) age of 71.0 (9.2) years; 119 participants (14.8%) were Black, 567 (70.3%) were Hispanic, and 105 (13.0%) were White. During a mean (SD) follow-up of 10.9 (3.7) years, new-onset ischemic stroke occurred in 53 participants (6.6%); incident AF was observed in 103 participants (12.8%). Compared with individuals who did not develop ischemic stroke, participants with ischemic stroke had lower positive longitudinal LAε and negative longitudinal LASR at baseline. In multivariable analysis, the lowest (ie, closest to zero) vs all other quintiles of positive longitudinal LAε (adjusted hazard ratio [HR], 3.12; 95% CI, 1.56-6.24) and negative longitudinal LASR during LA contraction (HR, 2.89; 95% CI, 1.44-5.80) were associated with incident ischemic stroke, independent of left ventricular global longitudinal strain and incident AF. Among participants with a normal LA size, the lowest vs all other quintiles of positive longitudinal LAε (HR, 4.64; 95% CI, 1.55-13.89) and negative longitudinal LASR during LA contraction (HR, 11.02; 95% CI 3.51-34.62) remained independently associated with incident ischemic stroke.

Conclusions and Relevance

This cohort study suggests that reduced positive longitudinal LAε and negative longitudinal LASR are independently associated with ischemic stroke in older adults. Assessment of LAε and LASR by speckle-tracking echocardiography may improve stroke risk stratification in elderly individuals.

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2023 Statistical Update is the product of a full year's worth of effort in 2022 by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. The American Heart Association strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional COVID-19 (coronavirus disease 2019) publications, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Novel dual-reference approach facilitates the activation mapping and catheter ablation of premature atrial complexes with non-pulmonary vein and non-superior vena cava origins

AIMS

Activation mapping of premature atrial complexes (PACs) proves challenging due to interference by mechanical bumping and non-targeted ectopies. This study aims to compare the mapping efficacy, instant success, and long-term recurrence of catheter ablation for PACs with non-pulmonary vein (PV) and non-superior vena cava (SVC) origins between the novel dual-reference approach (DRA) and the routine single-reference approach (SRA) of mapping.

METHODS AND RESULTS

Patients with symptomatic, drug-refractory PACs, or frequent residual PACs after atrial tachyarrhythmia ablation were enrolled. During activation mapping, the coronary sinus (CS) catheter was used as the only timing reference in the SRA group. In the DRA group, another catheter, which was spatially separated from the CS catheter, was used as the second reference. The timing difference between the two references was used to discriminate the targeted PACs from the uninterested rhythms. Procedural parameters and long-term recurrence were compared. A total of 188 patients (109 in SRA and 79 in DRA) were enrolled. The baseline characteristics were similar. Compared with the SRA group, the DRA group had less repeated mapping (1.2 ± 0.4 vs. 1.4 ± 0.5, P = 0.004), shorter mapping (15 ± 6 vs. 23 ± 7 min, P < 0.001) and procedural time (119 ± 28 vs. 132 ± 22 min, P = 0.001), similar procedural complication rates (3.6 vs. 3.8%, P > 0.999), higher instant success (96.2 vs. 87.2%, P = 0.039), and lower recurrence rate (15.2 vs. 29.3%, hazard ratio 1.943, P = 0.033) during a 24-month follow-up.

CONCLUSION

As a novel strategy, the DRA shortens the procedural time and improves both instant and long-term success of PAC ablation, serving as a promising approach in mapping PACs with non-PV and non-SVC origins.

Left atrial late gadolinium enhancement in patients with ischaemic stroke

AIMS

To evaluate the extent of left atrial (LA) fibrosis in patients with a recent stroke without atrial fibrillation and controls without established cardiovascular disease.

METHODS AND RESULTS

This prospectively designed study used cardiac magnetic resonance to detect LA late gadolinium enhancement as a proxy for LA fibrosis. Between 2019 and 2021, we consecutively included 100 patients free of atrial fibrillation with recent ischaemic stroke (<30 days) and 50 age- and sex-matched controls. LA fibrosis assessment was achieved in 78 patients and 45 controls. Blinded to the cardiac magnetic resonance results, strokes were adjudicated according to modified Trial of Org 10172 in Acute Stroke Treatment classification as undetermined aetiology (n = 42) or as attributable to large- or small-vessel disease (n = 36). Patients with stroke had a larger extent of LA fibrosis [6.9%, interquartile range (IQR) 3.6-15.4%] than matched controls (4.2%, IQR 2.3-7.5%; P = 0.007). No differences in LA fibrosis were observed between patients with stroke of undetermined aetiology and those with large- or small-vessel disease (6.6%, IQR 3.8-16.0% vs. 6.9%, IQR 3.4-14.6%; P = 0.73).

CONCLUSION

LA fibrosis was more extensive in patients with stroke than in age- and sex-matched controls. A similar extent of LA fibrosis was observed in patients with stroke of undetermined aetiology and stroke classified as attributable to large- or small-vessel disease. Our findings suggest that LA structural abnormality is more frequent in patients with stroke than in controls independent of aetiological classification.

Excessive Supraventricular Ectopic Activity and the Risk of Atrial Fibrillation and Stroke: A Systematic Review and Meta-Analysis

BACKGROUND

Excessive supraventricular ectopic activity (ESVEA) is correlated with the development of atrial fibrillation (AF) and is frequently observed in ischemic stroke patients. This meta-analysis aims to summarize the evidence on the association between ESVEA and the risk of AF and stroke.

METHODS

PubMed and Embase databases were systematically searched to identify all publications providing relevant data from inception to 23 August 2022. Hazard ratio (HR) and 95% confidence interval (CI) were pooled using fixed-effect or random-effect models.

RESULTS

We included 23,272 participants from 20 studies. Pooled results showed that ESVEA was associated with an increased risk of AF in the general population (HR: 2.57; 95% CI 2.16-3.05), increased risk of AF in ischemic stroke patients (HR: 2.91; 95% CI 1.80-4.69), new-onset ischemic stroke (HR: 1.91; 95% CI 1.30-2.79), and all-cause mortality (HR: 1.41; 95% CI 1.24-1.59). Pooled analysis indicated that ESVEA was not associated with recurrent ischemic stroke/transient ischemic attack (TIA) (HR: 1.24; 95% CI 0.91-1.67).

CONCLUSIONS

ESVEA is associated with AF, new-onset ischemic stroke, and all-cause mortality.

Left Atrial Strain and the Risk of Atrial Arrhythmias From Extended Ambulatory Cardiac Monitoring: MESA

Background Abnormalities in left atrial (LA) function often occur before LA structural changes and clinically identified atrial fibrillation (AF). Little is known about the relationship between LA strain and the risk of subclinical atrial arrhythmias detected from extended ambulatory cardiac monitoring. Methods and Results A total of 1441 participants of MESA (Multi-Ethnic Study of Atherosclerosis) completed speckle-tracking echocardiography and cardiac monitoring during 2016 to 2018 (mean age, 73 years); participants in AF during echocardiography or during the entire cardiac monitoring period were excluded. Absolute values of LA reservoir, booster pump, and conduit strains were measured. We evaluated associations of LA strain with monitor-detected AF, premature atrial contractions, and supraventricular tachycardia. Primary analyses adjusted for demographic variables, blood pressure, diabetes, smoking, and clinical cardiovascular disease. Cardiac monitoring (median, 14 days) detected AF in 3%. Each SD (4.0%) lower (worse) LA booster pump strain was associated with 84% higher risk of monitor-detected AF (95% CI, 30%-162%), 39% higher premature atrial contraction frequency (95% CI, 27%-53%), and 19% higher supraventricular tachycardia frequency (95% CI, 10%-29%). Additional adjustment for NT-proBNP (N-terminal pro-B-type natriuretic peptide), LA volume index, tissue Doppler a' peak velocity, left ventricular ejection fraction, and global longitudinal strain had little impact on associations. Findings were similar for LA reservoir strain and null for LA conduit strain. Conclusions In a multiethnic community-based cohort, impaired LA strain was an important correlate of subclinical atrial arrhythmias, even after adjustment for conventional measures of LA structure and function.

Premature atrial contractions: A predictor of atrial fibrillation and a relevant marker of atrial cardiomyopathy

An increased burden of premature atrial contractions (PACs) has long been considered a benign phenomenon. However, strong evidence of their involvement in the occurrence of atrial fibrillation (AF), ischemic stroke, and excess mortality suggests the need for management. The central question to be resolved is whether increased ectopic atrial rhythm is only a predictor of AF or whether it is a marker of atrial cardiomyopathy and therefore of ischemic stroke. After reviewing the pathophysiology of PACs and its impact on patient prognosis, this mini-review proposes to 1) detail the physiological and clinical elements linking PACs and AF, 2) present the evidence in favor of supraventricular ectopic activity as a marker of cardiomyopathy, and 3) outline the current limitations of this concept and the potential future clinical implications.

Genome-wide analyses identify SCN5A as a susceptibility locus for premature atrial contraction frequency

Premature atrial contractions (PACs) are frequently observed on electrocardiograms and are associated with increased risks of atrial fibrillation (AF), stroke, and mortality. In this study, we aimed to identify genetic susceptibility loci for PAC frequency. We performed a genome-wide association study meta-analysis with PAC frequency obtained from ambulatory cardiac monitoring in 4,831 individuals of European ancestry. We identified a genome-wide significant locus at the SCN5A gene. The lead variant, rs7373862, located in an intron of SCN5A, was associated with an increase of 0.12 [95% CI 0.08-0.16] standard deviations of the normalized PAC frequency per risk allele. Among genetic variants previously associated with AF, there was a significant enrichment in concordance of effect for PAC frequency (n = 73/106, p = 5.1 × 10-5). However, several AF risk loci, including PITX2, were not associated with PAC frequency. These findings suggest the existence of both shared and distinct genetic mechanisms for PAC frequency and AF.

Left Atrial Volumes and Function, and Long-Term Incidence of Ischemic Stroke in the General Population

Background Left atrial (LA) volumes and emptying fraction in the general population may address structural and functional aspects of atrial cardiomyopathy associated with long-term risk of ischemic stroke in the absence of atrial fibrillation or prior stroke. We investigated the association between LA volumes and function and ischemic stroke. Methods and Results In a community-based cohort, we measured LA minimal volume, LA maximal volume, and LA emptying fraction by transthoracic echocardiography. The primary end point was ischemic stroke. Participants with known atrial fibrillation or prior ischemic stroke were excluded, which resulted in 1866 participants. The mean age was 58±16 years, and 57% were women. During a median follow-up of 16.5 years (interquartile range: 11.4-16.8 years), 176 (9.4%) ischemic strokes occurred. In multivariable cause-specific regression models and competing risk models with death as a competing risk, LA emptying fraction was associated with ischemic stroke (hazard ratio [HR], 1.14 per 10% decrease [95% CI, 1.02-1.28]) and (subdistribution HR, 1.14 [95% CI, 1.01-1.29]). This association remained when adjusting for participants who developed atrial fibrillation during follow-up (HR, 1.12 per 10% decrease [95% CI, 1.00-1.26]). Indexed LA volumes were not associated with ischemic stroke in the same models. LA emptying fraction and indexed LA volumes were not associated with all-cause mortality. Conclusions Lower LA emptying fraction measured by transthoracic echocardiography was associated with future ischemic stroke independently of incident atrial fibrillation. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02993172.

A score to predict the stroke recurrence of patients with embolic stroke of undetermined source

AIM

We aimed to develop a score and validate it in a prospective cohort to identify the patients with ESUS at high risk for stroke recurrence.

METHODS

We assessed the stroke recurrence in ESUS patients of the Third China National Stroke Registry. We performed multivariable logistic regression analysis to identify predictors of stroke recurrence in the derivation cohort. Based on the coefficient of each covariate of the fitted multivariable model, we generated an integer-based point scoring system. We validated the score in the validation cohort assessing its discrimination and calibration.

RESULTS

2415 patients were included: 1611 in the derivation and 804 in the validation sample. We developed a scoring system (0-15 points) by assigning 2 points for hypertension, 3 points for diabetes mellitus, 4 points for multiple stage infarction, 2 points for watershed involved infarction, 1 points for left atrial diameter index (per increasing 2.5 mm/m2) and 3 points for without statin at discharge. The rate of stroke recurrence was 5.9% per year (95% CI 4.2-7.6%) in patients with low risk(a score of 0-5), 9.4% (7.3-11.5%) in patients with intermediate risk (6-10), and 26.8% (16.5-37.1%) in patients with high risk (11-15). The AUC (area under curve of receiver operator characteristic curve) of the score in the derivation cohort and validation cohort was, respectively, 0.60 (0.55-0.65) and 0.63 (0.56-0.70). The score was well calibrated both in the derivation cohort (p = 0.36) and validation cohort (p = 0.26) with the Hosmer-Lemeshow test.

CONCLUSION

The developed score can improve risk stratification after ESUS in secondary care settings.

Atrial cardiomyopathy in patients with ischaemic stroke: a cross-sectional and prospective cohort study-the COAST study

INTRODUCTION

Despite workup for the aetiology of ischaemic stroke, about 25% of cases remain unexplained. Paroxysmal atrial fibrillation is typically suspected but often not detected. Even if atrial fibrillation (AF) is detected, the quantitative threshold of clinically relevant AF remains unclear. Emerging evidence suggests that left atrial (LA) functional and structural abnormalities may convey a risk of ischaemic stroke in which AF is only one of several features. These abnormalities have been termed 'atrial cardiomyopathy'. This study uses cardiac magnetic resonance (CMR) to evaluate atrial cardiomyopathy among patients with stroke of undetermined aetiology compared with those with an attributable mechanism and controls without established cardiovascular disease.

METHODS AND ANALYSIS

This cross-sectional and prospective cohort study included 100 patients with recent ischaemic stroke and 50 controls with no established cardiovascular disease. The study will assess LA structural and functional abnormalities with CMR. Inclusion began in March 2019, and follow-up is planned to be complete in January 2023. There are two scheduled follow-ups: (1) 18 months after individual inclusion, counting from the index diagnostic MRI of the brain, (2) end of study follow-up at 18 months after inclusion of the last patient, assessing the incidence of recurrent ischaemic stroke, AF and cardiovascular death. The primary endpoint is the extent of CMR-assessed atrial fibrosis in the LA at baseline. The study is powered to detect a difference of 6% fibrosis between stroke of undetermined aetiology and stroke of known mechanism with a SD of 9%, a significance level of 0.05, and power of 80%.

ETHICS AND DISSEMINATION

This study has been approved by the Danish National Committee on Health Research Ethics (H-18055313). All participants in the study signed informed consent. Results from the study will be published in peer-reviewed journals regardless of the outcome.

TRIAL REGISTRATION NUMBER

NCT03830983.

Frequent premature atrial contractions as a signalling marker of atrial cardiomyopathy, incident atrial fibrillation and stroke

Premature atrial contractions are a common cardiac phenomenon. Although previously considered a benign electrocardiographic finding, they have now been associated with a higher risk of incident atrial fibrillation and other adverse outcomes such as stroke and all-cause mortality. Since premature atrial contractions can be associated with these adverse clinical outcomes independently of atrial fibrillation occurrence, different explanations have being proposed. The concept of atrial cardiomyopathy, where atrial fibrillation would be an epiphenomenon outside the causal pathway between premature atrial contractions and stroke has received traction recently. This concept suggests that structural, functional and biochemical changes in the atria lead to arrhythmia occurrence and thromboembolic events. Some consensus about diagnosis and treatment of this condition have been published, but this is based on scarce evidence, highlighting the need for a clear definition of excessive premature atrial contractions and for prospective studies regarding antiarrhythmic therapies, anticoagulation or molecular targets in this group of patients.

Cardiovascular Complications of Interatrial Conduction Block: JACC State-of-the-Art Review

Interatrial block (IAB) is an electrocardiographic pattern describing the conduction delay between the right and left atria. IAB is classified into 3 degrees of block that correspond to decreasing conduction in the region of Bachmann's bundle. Although initially considered benign in nature, specific subsets of IAB have been associated with atrial arrhythmias, elevated thromboembolic stroke risk, cognitive impairment, and mortality. As the pathophysiologic relationships between IAB and stroke are reinforced, investigation has now turned to the potential benefit of early detection, atrial imaging, cardiovascular risk factor modification, antiarrhythmic pharmacotherapy, and stroke prevention with oral anticoagulation. This review provides a contemporary overview of the epidemiology, pathophysiology, diagnosis, and management of IAB, with a focus on future directions.

Atrial Cardiopathy and Cryptogenic Stroke

Recent advances in pathophysiology suggest that a pathological atrial substrate can cause embolic stroke even in patients without atrial fibrillation (AF). This pathological condition is called “atrial cardiopathy”, which indicates atrial structural and functional disorders that can precede AF. The objective of this narrative review was to provide a current overview of atrial cardiopathy and cryptogenic stroke. We searched the PubMed database and summarized the recent findings of the identified studies, including the pathogenesis of atrial cardiopathy, biomarkers of atrial cardiopathy, relationship between atrial cardiopathy and cryptogenic stroke, and therapeutic interventions for atrial cardiopathy. Abnormal atrial substrate (atrial cardiopathy) that leads to AF can result in embolic stroke before developing AF, and may explain the source of cryptogenic stroke in some patients. Although there are several potential biomarkers indicative of atrial cardiopathy, P-wave terminal force in lead V1 (>5,000 μV^* ms), N-terminal pro-brain natriuretic peptide (>250 pg/ml), and left atrial enlargement are currently promising biomarkers for the diagnosis of atrial cardiopathy. Because the optimal combination and thresholds of biomarkers for diagnosing atrial cardiopathy remain uncertain, atrial cardiopathy represents a spectrum disorder. The concept of atrial cardiopathy appears to be most valuable as a starting point for therapeutic intervention to prevent stroke. Validation of the diagnosis of atrial cardiopathy and whether it can be used as a new therapeutic target for direct oral anticoagulants are currently being covered in the ARCADIA trial.

Heart Disease and Stroke Statistics-2022 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2022 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population and an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, and the global burden of cardiovascular disease and healthy life expectancy.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

The Beneficial Effects of Beta Blockers on the Long-Term Prognosis of Patients With Premature Atrial Complexes

Aims

Premature atrial complexes (PACs) have been reported to increase the risk of adverse cardiovascular outcomes. Beta blockers at low dosages may help to reduce PAC symptoms, but it is unclear whether they can improve long-term outcomes.

Methods

Patients enrolled from a Holter cohort in a medical referral center were stratified into high-burden (≥100 beats/24 h) and low-burden (<100 beats/24 h) sub-cohorts, and propensity score matching between treatment groups and non-treatment groups was conducted for each sub-cohort.

Results

In the high-burden sub-cohort, after propensity score matching, the treatment group and non-treatment group respectively had 208 and 832 patients. The treatment group had significantly lower mortality rates than the non-treatment group [hazard ratio (HR) = 0.521, 95% confidence interval (CI) = 0.294–0.923, p = 0.025], but there was no difference in new stroke (HR = 0.830, 95% CI = 0.341–2.020, p = 0.681), and new atrial fibrillation (HR = 1.410, 95% CI = 0.867–2.292, p = 0.167) events. In the low-burden sub-cohort, after propensity score matching, there were 614 patients in the treatment group and 1,228 patients in the non-treatment group. Compared to the non-treatment group, up to 40% risk reduction in mortality was found in the treatment group (HR = 0.601, 95% CI = 0.396–0.913, p = 0.017), but no differences in new stroke (HR =0.969, 95% CI = 0.562–1.670, p = 0.910) or atrial fibrillation (HR = 1.074, 95% CI = 0.619–1.863, p = 0.800) were found.

Conclusions

Beta blockers consistently decreased long-term mortality in high-burden and low-burden patients. Interestingly, this effect was not achieved through reduction of new-onset stroke or AF, and further research is warranted.

Evaluation of the Feasibility and Efficacy of a Novel Device for Screening Silent Atrial Fibrillation (MYBEAT Trial)

BACKGROUND

myBeat is a novel cutaneous patch device that continuously records electrocardiography and automatically detects atrial fibrillation (AF) by using a new algorithm based on RR intervals. We aimed to test the diagnostic ability of this novel device for screening silent AF in asymptomatic patients.

METHODS AND RESULTS

A multicenter randomized prospective clinical study was performed. To be eligible for inclusion in the study, patients had to be ≥65 years of age and have ≥1 of the following risk factors: hypertension, diabetes, heart failure, ischemic heart disease, stroke, and transient ischemic attack. Patients with prior AF, an implantable pacemaker, and previous palpitation or syncope were excluded. The 300 participants were divided into 2 groups, those using myBeat (n=150) or those undergoing 24-h Holter monitoring (control group; n=150), for AF screening. The rate of AF detection was significantly higher in the myBeat than control group (16 [10.7%] vs. 7 [4.7%], respectively; P=0.04). Multivariable logistic regression analysis revealed that prior heart failure was an independent predictor of silent AF (odds ratio 12.07; 95% confidence interval 1.67-86.27; P=0.01). A 7.7-fold difference in silent AF was found between subjects with CHA2DS2-VASc scores of 1 point and those with scores ≥4 points.

CONCLUSIONS

The novel patch device using an original algorithm was beneficial for screening of silent AF.

Continuous ECG monitoring versus mobile telemetry: A comparison of arrhythmia diagnostics in human- versus algorithmic-dependent systems

Background

Clinicians rarely scrutinize the full disclosure of a myriad of FDA-approved long-term rhythm monitors, and they rely on manufacturers to detect and report relevant rhythm abnormalities.

Objective

The objective of this study is to compare the diagnostic accuracy between mobile cardiac telemetry (MCT), which uses an algorithm-based detection strategy, and continuous long-term electrocardiography (LT-ECG) monitoring, which uses a human-based detection strategy.

Methods

In an outpatient arrhythmia clinic, we enrolled 50 sequential patients ordered to wear a 30-day MCT, to simultaneously wear a continuous LT-ECG monitor. Periods of concomitant wear of both devices were examined using the associated report, which was over-read by 2 electrophysiologists.

Results

Forty-six of 50 patients wore both monitors simultaneously for an average of 10.3 ± 4.4 days (range: 1.2–14.8 days). During simultaneous recording, patients were more often diagnosed with arrhythmia by LT-ECG compared to MCT (23/46 vs 11/46), P = .018. Similarly, more arrhythmia episodes were detected during simultaneous recording with the LT-ECG compared to MCT (61 vs 19), P < .001. This trend remained consistent across arrhythmia subtypes, including ventricular tachycardia (13 patients by LT-ECG vs 7 by MCT), atrioventricular (AV) block (3 patients by LT-ECG vs 0 by MCT), and AV node reentrant tachycardia (2 patients by LT-ECG vs 0 by MCT). Atrial fibrillation (AF) was documented by both monitors in 2 patients; however, LT-ECG monitoring captured 4 additional AF episodes missed by MCT.

Conclusion

In a time-controlled, paired analysis of 2 disparate rhythm monitors worn simultaneously, human-dependent LT-ECG arrhythmia detection significantly outperformed algorithm-based MCT arrhythmia detection.

Chronic Obstructive Pulmonary Disease and Risk of Atrial Arrhythmias After ST-Segment Elevation Myocardial Infarction

Background

ST-segment elevation myocardial infarction (STEMI) and cardiac arrhythmias frequently occur in patients with chronic obstructive pulmonary disease (COPD). However, little is known about the association of COPD with the occurrence of atrial arrhythmias after STEMI.

Methods

This retrospective analysis consisted of 320 patients with first STEMI without a history of atrial arrhythmias, with available 24-hour holter-ECG at 3- and/or 6 months follow-up. In total, 80 COPD patients were compared with 240 non-COPD patients, matched by age and gender (mean age 67±10 years, 74% male). Atrial arrhythmias were defined as: atrial fibrillation/flutter, atrial tachycardia (≥3 consecutive premature atrial contractions (PAC's)) and excessive supraventricular ectopy activity (ESVEA, ≥30 PAC's/hour or runs of ≥20 PAC's).

Results

Baseline characteristics were similar among COPD and non-COPD patients regarding infarct location, β-blocker use and cardiovascular risk profile except for smoking (69% vs. 49%, respectively, p=0.002). Additionally, atrial volumes, LVEF and TAPSE were comparable. During 1 year follow-up, a significantly higher prevalence of atrial tachycardia and ESVEA was observed in patients with COPD as compared to non-COPD patients (70% vs. 46%; p<0.001 and 21% vs. 11%; p=0.024, respectively). In multivariate analysis, COPD was independently associated with the occurrence of atrial arrhythmias (combined) during 1 year of follow-up (HR 3.59, 95% CI 1.78-7.22; p<0.001).

Conclusion

COPD patients after STEMI have a significantly higher prevalence of atrial tachycardia and ESVEA within 1 year follow-up as compared to age- and gender matched patients without COPD. Moreover, COPD is independently associated with an increased prevalence of atrial arrhythmias after STEMI.

Short coupling interval with high burden of atrial ectopy predicts recurrence after atrial fibrillation ablation

Atrial ectopy (AE) with a short coupling interval (S-AE) causes atrial fibrillation (AF). A higher burden of AE is associated with recurrence after AF ablation. However, a few reports have evaluated the prognostic impact of both AE burden and S-AE after the acute phase of ablation. This study aimed to assess the characteristics of AE beyond the blanking period in predicting the recurrence. We retrospectively analyzed 173 patients who underwent first catheter ablation for AF and 24-h Holter recording following a 3-month blanking period. AE was defined as a narrow QRS complex occurring < 75% earlier than the prior reference R-R interval. We investigated the relationship between the AE's characteristics in Holter recordings and atrial arrhythmia recurrence. Forty-two patients (24%) had a recurrence during a median 488-day follow-up. Patients with S-AE (minimum coupling interval ratio of AE ≤ 45%) had a higher recurrence rate than those without S-AE (44.9% vs. 16.1%, p < 0.001). Moreover, patients with AE ≥ 241/day exhibited a significantly higher recurrence rate than those with AE < 241/day (44.3% vs. 10.7%, p < 0.001). In multivariate analysis, S-AE with a higher AE burden was an independent predictor of recurrence (hazard ratio 5.82, 95% confidence interval: 2.64-12.82, p < 0.001). Kaplan-Meier analysis showed that patients with S-AE and a higher AE burden had the worst prognosis for recurrence (p < 0.001). The combination of a higher AE burden with S-AE could be an efficient predictor of recurrence. These results can help to develop follow-up strategies after AF ablation.

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.

Arrhythmias Other Than Atrial Fibrillation in Those With an Irregular Pulse Detected With a Smartwatch: Findings From the Apple Heart Study

[Figure: see text].

Localized Pulmonary Vein Scar Promotes Atrial Fibrillation in High Left Atrial Pressure

Background

Pulmonary vein (PV) ablation is unsuccessful in atrial fibrillation (AF) patients with high left atrial (LA) pressure. Increased atrial stretch by increased pressure is proarrhythmic for AF, and myocardial scar alters wall deformation. We hypothesized that localized PV scar is proarrhythmic for AF in high LA pressure.

Methods

Radiofrequency energy was delivered locally in the right PV of healthy sheep. The sheep recovered for 4 months. Explanted hearts (n = 9 PV scar, n = 9 controls) were perfused with 1:4 blood:Tyrode's solution in a four-chamber working heart setup. Programmed PV stimulation was performed during low (∼12 mmHg) and high (∼25 mmHg) LA pressure. An AF inducibility index was calculated based on the number of induction attempts and the number of attempts causing AF (run of ≥ 20 premature atrial complexes).

Results

In high LA pressure, the presence of PV scar increased the AF inducibility index compared with control hearts (0.83 ± 0.20 vs. 0.38 ± 0.40 arb. unit, respectively, p = 0.014). The diastolic stimulation threshold in high LA pressure was higher (108 ± 23 vs. 77 ± 16 mA, respectively, p = 0.006), and its heterogeneity was increased in hearts with PV scar compared with controls. In high LA pressure, the refractory period was shorter in PV scar than in control hearts (178 ± 39 vs. 235 ± 48 ms, p = 0.011).

Conclusion

Localized PV scar only in combination with increased LA pressure facilitated the inducibility of AF. This was associated with changes in tissue excitability remote from the PV scar. Localized PV ablation is potentially proarrhythmic in patients with increased LA pressure.