EHRA/HRS/APHRS/SOLAECE expert consensus on atrial cardiomyopathies: definition, characterization, and clinical implication

[Arrhythmias and amyloidosis]

Cardiac amyloidosis is an infiltrative cardiomyopathy characterized by the extracellular deposition of amyloid fibrils within the myocardium. Beyond heart failure, patients with cardiac amyloidosis commonly present with arrhythmias and conduction system disorders. Atrial fibrillation is observed in up to 80% of patients at the time of diagnosis, with patients typically maintaining normal heart rates due to concurrent atrioventricular nodal disease. The thromboembolic risk is particularly high in patients with cardiac amyloidosis, and left atrial thrombi have been observed even in the absence of atrial fibrillation. Conduction system diseases are also highly prevalent, often necessitating permanent pacemaker implantation. The use of implantable defibrillators in this population remains controversial. This overview of published data and therapeutic strategies related to arrhythmias and conduction system disorders aims to assist readers in decision-making in complex clinical scenarios.

Cardiac-specific overexpression of CREM-IbΔC-X via CRISPR/Cas9 in mice presents a new model of atrial cardiomyopathy with spontaneous atrial fibrillation

Atrial cardiomyopathy (ACM) forms the substrate for atrial fibrillation (AF) and underlies the potential for atrial thrombus formation and subsequent stroke. However, generating stable animal models that accurately replicate the entire progression of atrial lesions, particularly the onset of AF, presents significant challenges. In the present study, we found that the isoform of CRE-binding protein modulator (CREM-IbΔC-X), which is involved in the regulation of cardiac development and atrial rhythm, was highly expressed in atrial biopsies from patients with AF. Building upon this finding, we employed CRISPR/Cas9 technology to create a mouse model with cardiac-specific overexpression of CREM-IbΔC-X (referred to as CS-CREM mice). This animal model effectively illustrated the development of ACM through electrophysiological and structural remodelings over time. Proteomics and Chip-qPCR analysis of atrial samples revealed significant upregulation of cell-matrix adhesion and extracellular matrix structural components, alongside significant downregulation of genes related to atrial functions in the CS-CREM mice. Furthermore, the corresponding responses to anti-arrhythmia drugs, i.e., amiodarone and propafenone, suggested that CS-CREM mice could serve as an ideal in vivo model for drug testing. Our study introduced a novel ACM model with spontaneous AF by cardiac-specifically overexpressing CREM-IbΔC-X in mice, providing valuable insights into the mechanisms and therapeutic targets of ACM.

Novel electrocardiographic classification for stroke prediction in atrial fibrillation patients undergoing cardioversion

BACKGROUND

Abnormal conduction, structure and function of the atrial myocardium predispose to atrial fibrillation (AF) and stroke. Usefulness of electrocardiographic (ECG) indices in predicting stroke or systemic embolism (SSE) in patients undergoing cardioversion for AF remains unknown, especially in those at low estimated risk.

OBJECTIVE

To systematically evaluate the performance of various P-wave abnormalities (PWA) in predicting SSE 30 days after cardioversion (derivation cohort) and in the long-term (validation cohort).

METHODS

ECGs (n=1773) of AF patients undergoing an acute cardioversion were manually reviewed. The 30-day post-cardioversion data was used to derive a composite PWA variable. The ECG findings were validated using the long-term follow-up of patients with no anticoagulation. ECGs of 27 CAREBANK study patients with right atrial appendage biopsies were further analyzed for histopathological validation.

RESULTS

During data derivation, the best performance was found using a combination of prolonged P-wave (≥180ms), deflected P-wave morphology in lead II, biphasic P-waves in inferior leads or increased P-terminal force (≥80mm*ms) as markers for extensive PWA. In the validation cohort 219/874 (25.1%) had extensive PWA. During a median follow-up of 4.9 years, there were 51 (5.8%) SSE in total. In a competing risk model PWA predicted SSE (aHR 2.1 per category, 95%CI 1.4-3.1, p<0.001). Area under the curve for SSE at 3 years were 0.77, 0.79 and 0.86 for PWA, CHA2DS2-VASc score or their combination, respectively. Histologically, extensive PWA was associated with interstitial fibrosis (p=0.033).

CONCLUSION

Novel electrocardiographic PWA classification provided additional prognostic insight in AF patients.

Atrial Cardiomyopathy Predicts the Functional Outcome and Mortality in Stroke Patients

AIM

Atrial cardiomyopathy (ACM) is characterized by atrial dysfunction. This study aims to assess the prognostic significance of ACM in patients with noncardioembolic stroke (NCS).

METHODS

Patients with NCS within seven days of onset were prospectively enrolled between January 2019 and December 2020. ACM was defined as either an N-terminal pro-brain natriuretic peptide (NT-pro BNP) ＞250 pg/ml or a P-terminal force in precordial lead V1 (PTFV1) ≥ 5000µV·ms. A poor functional outcome was determined as a score of 3-6 on the modified Rankin Scale (mRS) within a 2-year follow-up period. Logistic regression and Cox regression analyses were employed to examine the relationship between ACM and the long-term prognosis of patients with NCS.

RESULTS

A total of 1,346 patients were enrolled, of whom 299 (22.2%) patients were diagnosed with ACM. A total of 207(15.4%) patients experienced a poor functional outcome, and 58 (4.3%) patients died. A multivariate logistic regression analysis indicated that ACM was significantly associated with a poor functional outcome in NCS patients [adjusted odds ratio (aOR): 2.01; 95% confidence interval (CI): 1.42-2.87; p＜0.001]. Additionally, a multivariate Cox regression analysis showed that an NT-pro BNP ＞250 pg/ml was significantly associated with an increased risk of all-cause mortality [adjusted hazard ratio (aHR), 2.51; 95% CI: 1.42-4.43; p=0.001].

CONCLUSIONS

ACM may serve as a novel predictor of a poor long-term functional outcome in patients with NCS. Elevated NT-pro BNP levels (＞250 pg/ml) were found to be associated with a higher risk of all-cause mortality. These findings warrant further validation in multicenter studies.

Atrial fibrillation: age at diagnosis, incident cardiovascular events, and mortality

BACKGROUND AND AIMS

Patients with atrial fibrillation (AF) are at increased risks of cardiovascular diseases and mortality, but risks according to age at diagnosis have not been reported. This study investigated age-specific risks of outcomes among patients with AF and the background population.

METHODS

This nationwide population-based cohort study included patients with AF and controls without outcomes by the application of exposure density matching on the basis of sex, year of birth, and index date. The absolute risks and hazard rates were stratified by age groups and assessed using competing risk survival analyses and Cox regression models, respectively. The expected differences in residual life years among participants were estimated.

RESULTS

The study included 216 579 AF patients from year 2000 to 2020 and 866 316 controls. The mean follow-up time was 7.9 years. Comparing AF patients with matched controls, the hazard ratios among individuals ≤50 years was 8.90 [95% confidence interval (CI), 7.17-11.0] for cardiomyopathy, 8.64 (95% CI, 7.74-9.64) for heart failure, 2.18 (95% CI, 1.89-2.52) for ischaemic stroke, and 2.74 (95% CI, 2.53-2.96) for mortality. The expected average loss of life years among individuals ≤50 years was 9.2 years (95% CI, 9.0-9.3) years. The estimates decreased with older age.

CONCLUSIONS

The findings show that earlier diagnosis of AF is associated with a higher hazard ratio of subsequent myocardial disease and shorter life expectancy. Further studies are needed to determine causality and whether AF could be used as a risk marker among particularly younger patients.

A phase 1 trial of AP30663, a KCa2 channel inhibitor in development for conversion of atrial fibrillation

AIMS

AP30663 is a novel compound under development for pharmacological conversion of atrial fibrillation by targeting the small conductance Ca2+ activated K+ (KCa2) channel. The aim of this extension phase 1 study was to test AP30663 at higher single doses compared to the first-in-human trial.

METHODS

Sixteen healthy male volunteers were randomized into 2 cohorts: 6- and 8-mg/kg intravenous single-dose administration of AP30663 vs. placebo. Safety, pharmacokinetic and pharmacodynamic data were collected.

RESULTS

AP30663 was associated with mild and transient infusion site reactions with no clustering of other adverse events but with an estimated maximum mean QTcF interval prolongation of 45.2 ms (95% confidence interval 31.5-58.9) in the 6 mg/kg dose level and 50.4 ms (95% confidence interval 36.7-64.0) with 8 mg/kg. Pharmacokinetics was dose proportional with terminal half-life of around 3 h.

CONCLUSION

AP30663 in doses up to 8 mg/kg was associated with mild and transient infusion site reactions and an increase of the QTcF interval. Supporting Information support that the QTc effect may be explained by an off-target inhibition of the IKr channel.

Left atrial reservoir longitudinal strain and its incremental value to the left ventricular global longitudinal strain in predicting anthracycline-induced cardiotoxicity

BACKGROUND

Left ventricular global longitudinal strain (LVGLS) has been recommended by current guidelines for diagnosing anthracycline-induced cardiotoxicity. However, little is known about the early changes in left atrial (LA) morphology and function in this population. Our study aimed to evaluate the potential usefulness of LA indices and their incremental value to LVGLS with three-dimensional echocardiography (3DE) in the early detection of subclinical cardiotoxicity in patients with lymphoma receiving anthracycline.

METHODS

A total of 80 patients with diffuse large B-cell lymphoma who received six cycles of anthracycline-based treatment were enrolled. Echocardiography was performed at baseline (T0), after four cycles (T1), and after the completion of six cycles of chemotherapy (T2). Left ventricular ejection fraction (LVEF), LVGLS, LA volumes, LA emptying fraction (LAEF), LA active emptying fraction (LAAEF), and LA reservoir longitudinal strain (LASr) were quantified with 3DE. Left atrioventricular global longitudinal strain (LAVGLS) was calculated as the sum of peak LASr and the absolute value of peak LVGLS (LAVGLS = LASr+|LVGLS|). LV cardiotoxicity was defined as a new LVEF reduction by ≥10 percentage points to an LVEF of ≤50%.

RESULTS

Fourteen (17.5%) patients developed LV cardiotoxicity at T2. LA volumes, LAEF, and LAAEF remained stable over time. Impairment of LASr (28.35 ± 5.03 vs. 25.04 ± 4.10, p < .001), LVGLS (-22.77 ± 2.45 vs. -20.44 ± 2.62, p < .001), and LAVGLS (51.12 ± 5.63 vs. 45.61 ± 5.22, p < .001) was observed by the end of the fourth cycle of chemotherapy (T1). Statistically significant declines in LVEF (61.30 ± 4.73 vs. 57.08 ± 5.83, p < .001) were only observed at T2. The relative decrease in LASr (ΔLASr), LVGLS (ΔLVGLS), and LAVGLS (ΔLAVGLS) from T0 to T1 were predictors of LV cardiotoxicity. A ΔLASr of >19.75% (sensitivity, 71.4%; specificity, 87.9%; area under the curve (AUC), .842; p < .001), a ΔLVGLS of >13.19% (sensitivity, 78.6%; specificity, 74.2%; AUC, .763; p < .001), and a ΔLAVGLS of >16.80% (sensitivity, 78.6%; specificity, 93.9%; AUC, .905; p < .001) predicted subsequent LV cardiotoxicity at T2, with the AUC of ΔLAVGLS significantly larger than that of ΔLVGLS (.905 vs. .763, p = .027). Compared to ΔLVGLS, ΔLAVGLS showed improved specificity (93.9% vs. 74.2%, p = .002) and maintained sensitivity in predicting LV cardiotoxicity.

CONCLUSIONS

LASr could predict anthracycline-induced LV cardiotoxicity with excellent diagnostic performance. Incorporating LASr into LVGLS (LAVGLS) led to a significantly improved specificity and maintained sensitivity in predicting LV cardiotoxicity.

Left atrial cardiomyopathy: Pathophysiological insights, assessment methods and clinical implications

Atrial cardiomyopathy is defined as any complex of structural, architectural, contractile or electrophysiological changes affecting atria, with the potential to produce clinically relevant manifestations. Most of our knowledge about the mechanistic aspects of atrial cardiomyopathy is derived from studies investigating animal models of atrial fibrillation and atrial tissue samples obtained from individuals who have a history of atrial fibrillation. Several noninvasive tools have been reported to characterize atrial cardiomyopathy in patients, which may be relevant for predicting the risk of incident atrial fibrillation and its related outcomes, such as stroke. Here, we provide an overview of the pathophysiological mechanisms involved in atrial cardiomyopathy, and discuss the complex interplay of these mechanisms, including aging, left atrial pressure overload, metabolic disorders and genetic factors. We discuss clinical tools currently available to characterize atrial cardiomyopathy, including electrocardiograms, cardiac imaging and serum biomarkers. Finally, we discuss the clinical impact of atrial cardiomyopathy, and its potential role for predicting atrial fibrillation, stroke, heart failure and dementia. Overall, this review aims to highlight the critical need for a clinically relevant definition of atrial cardiomyopathy to improve treatment strategies.

Pathophysiology and clinical relevance of atrial myopathy

Atrial myopathy is a condition that consists of electrical, structural, contractile, and autonomic remodeling of the atria and is the substrate for development of atrial fibrillation, the most common arrhythmia. Pathophysiologic mechanisms driving atrial myopathy are inflammation, oxidative stress, atrial stretch, and neurohormonal signals, e.g., angiotensin-II and aldosterone. These mechanisms initiate the structural and functional remodeling of the atrial myocardium. Novel therapeutic strategies are being developed that target the pathophysiologic mechanisms of atrial myopathy. In this review, we will discuss the pathophysiology of atrial myopathy, as well as diagnostic and therapeutic strategies.

An Increase in the Left Atrium Volume During Exercise is Associated With a Positive Result of a Diastolic Stress Test in Patients With Arterial Hypertension

AIM

To study the relationship between changes in left atrial volume (LAV) during exercise and the result of a diastolic stress test (DST) in patients with arterial hypertension (AH).

MATERIAL AND METHODS

The study included 219 patients with AH without ischemic heart disease and atrial fibrillation. During the DST performed before and after exercise, the ratio of transmitral flow velocity to mitral annular velocity (E/e'), the left atrial global longitudinal strain in the reservoir phase (reservoir strain), and LAV were determined. The criterion for a positive DST was an increase in E/e' ≥15.

RESULTS

A positive result of DST was observed in 90 (41.1%) patients. Patients with positive DST were older (65.0 and 59.0 years); among them, there were fewer men (24.4 and 41.1%), but more patients with obesity (66.7 and 40.3%) and diabetes mellitus (36.7 and 8.5%). At rest, patients with positive DST had higher E/e' ratio (11.5 and 8.8), pulmonary artery systolic pressure (29.0 and 27.0 mm Hg), and LAV (60.0 and 52.0 ml), but a lower left atrial reservoir strain (20.0 and 24.0%). During exercise in patients with positive and negative DST, E/e' increased by 5.46 and 0.47 units, respectively. Changes in the LAV and reservoir strain during exercise in these groups were directed differently. In patients with positive DST, the left atrial reservoir strain decreased by 1.0 percentage points (pp) whereas in patients with negative DST, it increased by 8.0 pp. During exercise, the LAV increased by 10.0 ml in patients with a positive DST, whereas in the alternative group, the LAV decreased by 8.5 ml. The AUC for changes in LAV as an indicator of a positive DST was 0.987 while the AUC for the resting left atrial reservoir strain was 0.938. An increase in LAV >1 ml, as an indicator of a positive DST has a sensitivity of 96.9% and a specificity of 95.1%.

CONCLUSION

In AH patients, changes in left ventricular filling pressure are associated with a unidirectional change in LAV. An increase in LAV during exercise by more than 1 ml can serve as a criterion for a positive DST result. This assessment was consistent with the assessment of the DST result by the E/e' criterion >15 in 94.5% of cases.

Functional Mitral Regurgitation and Heart Failure With Preserved Ejection Fraction: Clinical Implications and Management

Heart failure with preserved ejection fraction (HFpEF) is highly prevalent and associated with worse cardiovascular outcomes. The pathophysiology of HFpEF mostly relies on the development of elevated left ventricle filling pressure, diastolic dysfunction, and atrial dilatation and impairment. This dynamic process may eventually lead to the development of functional mitral regurgitation (MR), characterized by mitral annular dilatation and consequent leaflet remodeling, in the context of preserved left ventricular ejection fraction. These observations highlight the possible common pathophysiology of MR and HFpEF. However, less is known about the prevalence and the clinical value of MR in the context of HFpEF. This review aims to provide an overview of the association and interplay between functional MR and HFpEF, discuss the underlying mechanisms that are common to these diseases, and summarize potential targeted pharmacological treatments.

Catheter ablation for non-paroxysmal atrial fibrillation. A review

Atrial fibrillation (AF), the most common cardiac arrhythmia is associated with increased morbidity and mortality. The higher mortality is due to the risk of heart failure and cardioembolic events. This in-depth review focuses on the strategies and efficacy of catheter ablation for non-paroxysmal atrial fibrillation. The main medical databases were searched for contemporary studies on catheter ablation for non-paroxysmal AF. Catheter ablation is currently proven to be the most effective treatment for AF and consists of pulmonary vein isolation as the cornerstone plus additional ablations. In terms of SR maintenance, it is less effective in non-paroxysmal AF than in paroxysmal patients. but the clinical benefit in non-paroxysmal patients is substantially higher. Since pulmonary vein isolation is ineffective, a variety of techniques have been developed, e.g. linear ablations, ablation of complex atrial fractionated electrograms, etc. Another paradox consists in the technique of catheter ablation. Despite promising results in early observation studies, further randomized studies have not confirmed the initial enthusiasm. Recently, a new approach, pulsed-field ablation, appears promising. This is an in-depth summary of current technologies and techniques for the ablation of non-paroxysmal AF. We discuss the benefits, risks and implications in the treatment of patients with non-paroxysmal AF.

Impaired retinal micro-vascular function in patients with atrial fibrillation

BACKGROUND

Cardiovascular (CV) risk factors and CV diseases, in particular heart failure, are strongly associated with impaired microvascular retinal endothelial function. Whether atrial fibrillation (AF) contributes to vascular dysfunction is not clear. Therefore, the aim of this study was to investigate the impact of AF on retinal microvascular function.

METHODS

In this study, vascular function was measured non-invasively with flicker-light induced vasodilatation of retinal arterioles (FIDart%). Patients with a history of AF and risk factors for heart failure (HF) or heart failure (n = 69; age 67.9 ± 9.2 years, 71% male, 35% HFrEF, 56% paroxysmal, 25% persistent, 19% permanent AF), as well as age, sex and ejection fraction matched patients with absent history of AF (n = 66; age 63.4 ± 10.6 years, 67% male, 47% HFrEF) were included. Patients with AF were further divided into those with paroxysmal AF (in sinus rhythm - AFSR: n = 38, age 71.4 ± 9.2, 73% male), and those with AF at the time of the study visit.

RESULTS

Retinal microvascular function was impaired in patients with AF compared to patients without AF (FIDart% 1.1% [0.3-2.8] vs. 2.7% [1.3-5.1], p < 0.001). Patients currently in AF have poorer retinal microvascular function (FIDart% 0.8% [0.1-1.9) compared to patients with a history of AF but currently in SR at the time of retinal function measurement (1.5% [0.6-4.9] p = 0.017). In patients with AF, impaired retinal vascular function was independently associated with larger left atrial volume (mean 49.8 ± 18.4), even after correction for confounding factors in different models (SCR = -0. 251 to -0.256, p = 0.035-0.01).

CONCLUSIONS

AF in patients with heart failure is associated with impaired vascular function, even if currently in sinus rhythm. The association of retinal microvascular dysfunction with left atrial volume, a surrogate for elevated cardiac filling pressures, may further highlight the important interplay between the vasculature and elevated filling pressures in the development of AF.

Fine tuning contractility: atrial sarcomere function in health and disease

The molecular mechanisms of sarcomere proteins underlie the contractile function of the heart. Although our understanding of the sarcomere has grown tremendously, the focus has been on ventricular sarcomere isoforms due to the critical role of the ventricle in health and disease. However, atrial-specific or -enriched myofilament protein isoforms, as well as isoforms that become expressed in disease, provide insight into ways this complex molecular machine is fine-tuned. Here, we explore how atrial-enriched sarcomere protein composition modulates contractile function to fulfill the physiological requirements of atrial function. We review how atrial dysfunction negatively affects the ventricle and the many cardiovascular diseases that have atrial dysfunction as a comorbidity. We also cover the pathophysiology of mutations in atrial-enriched contractile proteins and how they can cause primary atrial myopathies. Finally, we explore what is known about contractile function in various forms of atrial fibrillation. The differences in atrial function in health and disease underscore the importance of better studying atrial contractility, especially as therapeutics currently in development to modulate cardiac contractility may have different effects on atrial sarcomere function.

Does asymptomatic atrial fibrillation exist?

Atrial fibrillation (AF) is currently defined as symptomatic by asking patients if they are aware of when they are in AF and if they feel better in sinus rhythm. However, this approach of defining AF as symptomatic and asymptomatic fails to adequately consider the adverse effects of AF in patients who are unaware of their rhythm including progression from paroxysmal to persistent AF, and the development of dementia, stroke, sinus node dysfunction, valvular regurgitation, ventricular dysfunction, and heart failure. Labeling these patients as asymptomatic falsely suggests that their AF requires less intense therapy and puts into question the notion of truly asymptomatic AF. Because focusing on patient awareness ignores other important consequences of AF, clinical endpoints that are independent of symptoms are being developed. The concept of AF burden has more recently been used as a clinical endpoint in clinical trials as a more clinically relevant endpoint compared to AF-related symptoms or time to first recurrence, but its correlation with symptoms and other clinical outcomes remains unclear. This review will explore the impact of AF on apparently asymptomatic patients, the use of AF burden as an endpoint for AF management, and potential refinements to the AF burden metric. The review is based on a presentation by the senior author during the 2023 16th annual European Cardiac Arrhythmia Society (ECAS) congress in Paris, France.

The relationship between atrial cardiopathy biomarkers and prognosis of patients with acute ischemic stroke after endovascular treatment

Thromboembolism is a possible consequence of underlying atrial cardiopathy, which can occur even before the onset of atrial fibrillation. Our objective was to examine the association between biomarkers of atrial cardiopathy and outcomes of acute ischemic stroke (AIS) following endovascular treatment (EVT). We conducted a retrospective study that collected data from patients with AIS who underwent EVT and compared the outcomes between those with and without atrial cardiopathy. Neurological function was assessed using the modified Rankin Scale (mRS), with an mRS score >2 indicating poor function at day 90. Additionally, we evaluated secondary consequences, including symptomatic intracerebral hemorrhage (sICH), early neurological deterioration (END), and malignant cerebral edema (MCE). Our study included 87 patients (77.6 ​% male; mean age 60.93 ​± ​12.47 years). Among these patients, 29 (33.3 ​%) had atrial cardiopathy, while the remaining 58 (66.7 ​%) did not. In the atrial cardiopathy group, 12 patients (41.4 ​%) had poor functional outcomes (mRS>2), compared to 19 (32.8 ​%) in the non-atrial cardiopathy group. We observed sICH in 22 (25.3 ​%) patients, END in 14 (16.1 ​%) patients, MCE in 11 (12.6 ​%) patients, and two (2.3 ​%) patients who died in the hospital. We found that patients with PTFV1>5000 ​μV/ms (OR: 8.39, 95 ​% CI: 1.43-105.95, P ​= ​0.02) and NT-proBNP>250 ​pg/mL (OR: 5.09, 95 ​% CI: 1.20-27.63, P ​= ​0.03) had significantly higher risk of END. After adjusting for covariates in the Firth logistic regression, we further found that atrial cardiopathy was significantly associated with END, as revealed by both univariate (OR: 6.31, 95 ​% CI: 1.42-59.87, P ​= ​0.01) and multivariable firth regression models (Modle 1, OR: 7.10, 95 ​% CI: 1.57-67.38, P ​< ​0.01; Modle 2, OR: 7.82, 95 ​% CI: 1.69, 76.36, P ​< ​0.01; Modle 3, OR: 8.59, 95 ​% CI: 1.72-91.70, P ​< ​0.01). Moreover, we observed that atrial cardiopathy was associated with an increased risk of END in AIS patients with large artery atherosclerosis (LAA) receiving EVT. Therefore, clinicians should consider atrial cardiopathy as a possible underlying cause of AIS in their patients. Further investigation is warranted to elucidate the relationship between atrial cardiopathy and AIS's occurrence, progression, and prognosis.

Practical approach for atrial cardiomyopathy characterization in patients with atrial fibrillation

Atrial fibrillation (AF) causes progressive structural and electrical changes in the atria that can be summarized within the general concept of atrial remodeling. In parallel, other clinical characteristics and comorbidities may also affect atrial tissue properties and make the atria susceptible to AF initiation and its long-term persistence. Overall, pathological atrial changes lead to atrial cardiomyopathy with important implications for rhythm control. Although there is general agreement on the role of the atrial substrate for successful rhythm control in AF, the current classification oversimplifies clinical management. The classification uses temporal criteria and does not establish a well-defined strategy to characterize the individual-specific degree of atrial cardiomyopathy. Better characterization of atrial cardiomyopathy may improve the decision-making process on the most appropriate therapeutic option. We review current scientific evidence and propose a practical characterization of the atrial substrate based on 3 evaluation steps starting with a clinical evaluation (step 1), then assess outpatient complementary data (step 2), and finally include information from advanced diagnostic tools (step 3). The information from each of the steps or a combination thereof can be used to classify AF patients in 4 stages of atrial cardiomyopathy, which we also use to estimate the success on effective rhythm control.

The relationship between right atrial wall inflammation and poor prognosis of atrial fibrillation based on 18F-FDG positron emission tomography/computed tomography

Background

Atrial fibrillation (AF) has been identified to increase stroke risk, even after oral anticoagulants (OACs), and the recurrence rate is high after radiofrequency catheter ablation (RFCA). Inflammation is an essential factor in the occurrence and persistence of AF. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) is an established molecular imaging modality to detect local inflammation. We aimed to investigate the relationship between atrial inflammatory activity and poor prognosis of AF based on 18F-FDG PET/CT.

Methods

A total of 204 AF patients including 75 with paroxysmal AF (ParAF) and 129 with persistent AF (PerAF) who underwent PET/CT before treatment were enrolled in this prospective cohort study. Clinical data, electrocardiograph (ECG), echocardiography, and cardiac 18F-FDG uptake were collected. Follow-up information was obtained from patient clinical case notes or telephone reviews, with the starting point being the time of PET/CT scan. The follow-up deadline was either the date of AF recurrence after RFCA, new-onset stroke, or May 2023. Cox proportional hazards regression models were used to identify predictors of poor prognosis and hazard ratios (HRs) with 95% confidence intervals (CIs) was calculated.

Results

Median follow-up time was 29 months [interquartile range (IQR), 22-36 months]. Poor prognosis occurred in 52 patients (25.5%), including 34 new-onset stroke patients and 18 recrudescence after RFCA. The poor prognosis group had higher congestive heart failure, hypertension, age ≥75 years (doubled), diabetes mellitus, prior stroke or transient ischemic attack (TIA) or thromboembolism (doubled), vascular disease, age 65-74 years, sex category (female) (CHA2DS2-VASc) score [3.0 (IQR, 1.0-3.75) vs. 2.0 (IQR, 1.0-3.0), P=0.01], right atrial (RA) wall maximum standardized uptake value (SUVmax) (4.13±1.82 vs. 3.74±1.58, P=0.04), higher percentage of PerAF [39 (75.0%) vs. 90 (59.2%), P=0.04], left atrial (LA) enlargement [45 (86.5%) vs. 104 (68.4%), P=0.01], and RA wall positive FDG uptake [40 (76.9%) vs. 79 (52.0%), P=0.002] compared with the non-poor prognosis group. Univariate and multivariate Cox proportional hazard regression analysis concluded that only CHA2DS2-VASc score (HR, 1.29; 95% CI: 1.06-1.57; P=0.01) and RA wall positive FDG uptake (HR, 2.68; 95% CI: 1.10-6.50; P=0.03) were significantly associated with poor prognosis.

Conclusions

RA wall FDG positive uptake based on PET/CT is tightly related to AF recurrence after RFCA or new-onset stroke after antiarrhythmic and anticoagulation treatment.

Atrial fibrillation in human patients is associated with increased collagen type V and TGFbeta1

Background and aim

Atrial fibrosis is an important factor in initiating and maintaining atrial fibrillation (AF). Collagen V belongs to fibrillar collagens. There are, however no data on collagen V in AF. The aim of this work was to study the quantity of collagen V and its relationship with the number of fibroblasts and TGF- b 1 expression in patients in sinus rhythm (SR) and in patients with atrial fibrillation (AF).

Methods

We used quantitative immuhistochemistry to study collagen V in right and left atrial biopsies obtained from 35 patients in SR, 35 patients with paroxysmal AF (pAF) and 27 patients with chronic, long-standing persistent AF (cAF). In addition, we have quantified the number of vimentin-positive fibroblasts and expression levels of TGF-β1.

Results

Compared to patients in SR, collagen V was increased 1.8- and 3.1-fold in patients with pAF and cAF, respectively. In comparison with SR patients, the number of vimentin-positive cells increased significantly 1.46- and 1.8-fold in pAF and cAF patients, respectively.Compared to SR patients, expression levels of TGF-ß1, expressed as fluorescence units per tissue area, was significantly increased by 77 % and 300 % in patients with pAF and cAF, respectively. Similar to intensity measurements, the number of TGFß1-positive cells per 1 mm2 atrial tissue increased significantly from 35.5 ± 5.5 cells in SR patients to 61.9 ± 12.4 cells in pAF and 131.5 ± 23.5 cells in cAF. In both types of measurements, there was a statistically significant difference between pAF and cAF groups.

Conclusions

This is the first study to show that AF is associated with increased expression levels of collagen V and TGF-ß1indicating its role in the pathogenesis of atrial fibrosis. In addition, increases in collagen V correlate with increased number of fibroblasts and TGF-β1 and are more pronounced in cAF patients than those in pAF patients.

Drug-induced atrial fibrillation. A narrative review of a forgotten adverse effect

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with an increased morbidity and mortality. There is clinical evidence that an increasing number of cardiovascular and non-cardiovascular drugs, mainly anticancer drugs, can induce AF either in patients with or without pre-existing cardiac disorders, but drug-induced AF (DIAF) has not received the attention that it might deserve. In many cases DIAF is asymptomatic and paroxysmal and patients recover sinus rhythm spontaneously, but sometimes, DIAF persists, and it is necessary to perform a cardioversion. Furthermore, DIAF is not mentioned in clinical guidelines on the treatment of AF. The risk of DIAF increases in elderly and in patients treated with polypharmacy and with risk factors and comorbidities that commonly coexist with AF. This is the case of cancer patients. Under these circumstances ascribing causality of DIAF to a given drug often represents a clinical challenge. We review the incidence, the pathophysiological mechanisms, risk factors, clinical relevance, and treatment of DIAF. Because of the limited information presently available, further research is needed to obtain a deeper insight into DIAF. Meanwhile, it is important that clinicians are aware of the problem that DIAF represents, recognize which drugs may cause DIAF, and consider the possibility that a drug may be responsible for a new-onset AF episode.

Left atrial strain: A memory of the severity of atrial myocardial stress in atrial fibrillation

BACKGROUND

Left atrial (LA) strain is a simple marker of LA function. The aim of the study was to evaluate the determinants of atrial cardiomyopathy in AF.

METHODS

In this pilot study, we prospectively evaluated clinical, biological, metabolomic and echocardiographic parameters for 85 consecutive patients hospitalized for atrial fibrillation (AF) with restoration of sinus rhythm at 6 months. Eighty-one patients with an analysable LA strain at 6 months were divided into groups according to median reservoir strain:<23.3% (n=40) versus≥23.3% (n=41).

RESULTS

Compared to patients with the highest LA strain, patients with lowest LA strain had multiple differences at admission: clinical (older age; more frequent history of AF; more patterns of persistent AF); biological (higher fasting blood glucose levels, glycated haemoglobin, high-sensitivity C-reactive protein, and urea; lower glomerular filtration rate); metabolomic (higher levels of kynurenine, kynurenine/tryptophan, and urea/creatinine; lower levels of arginine and methionine/methionine sulfoxide); and echocardiographic (higher two-dimensional end-systolic LA volume [LAV] indexes; higher three-dimensional end-systolic and end-diastolic LAV and right atrial volume indexes; lower LA and right atrial emptying fractions and three-dimensional right ventricular ejection fraction) (all P<0.05). Area under the receiver operating characteristic curve to predict LA strain alteration at 6 months was highest for a combined score including clinical, biological, metabolomic and echocardiographic variables at admission (area under the receiver operating characteristic curve 0.871; P<0.0001).

CONCLUSIONS

LA reservoir strain could be a memory of initial atrial myocardial stress in AF. It can be predicted using a combination of clinical, biological, metabolomic and echocardiographic admission variables.

Myocardial Interstitial Fibrosis in Hypertensive Heart Disease: From Mechanisms to Clinical Management

Hypertensive heart disease (HHD) can no longer be considered as the beneficial adaptive result of the hypertrophy of cardiomyocytes in response to pressure overload leading to the development of left ventricular hypertrophy. The current evidence indicates that in patients with HHD, pathological lesions in the myocardium lead to maladaptive structural remodeling and subsequent alterations in cardiac function, electrical activity, and perfusion, all contributing to poor outcomes. Diffuse myocardial interstitial fibrosis is probably the most critically involved lesion in these disorders. Therefore, in this review, we will focus on the histological characteristics, the mechanisms, and the clinical consequences of myocardial interstitial fibrosis in patients with HHD. In addition, we will consider the most useful tools for the noninvasive diagnosis of myocardial interstitial fibrosis in patients with HHD, as well as the most effective available therapeutic strategies to prevent its development or facilitate its regression in this patient population. Finally, we will issue a call to action for the need for more fundamental and clinical research on myocardial interstitial fibrosis in HHD.

Clinical-imaging-pathological correlation in pulmonary hypertension associated with left heart disease

Pulmonary hypertension (PH) is highly prevalent in patients with left heart disease (LHD) and negatively impacts prognosis. The most common causes of PH associated with LHD (PH-LHD) are left heart failure and valvular heart disease. In LHD, passive backward transmission of increased left-sided filling pressures leads to isolated post-capillary PH. Additional pulmonary vasoconstriction and remodelling lead to a higher vascular load and combined pre- and post-capillary PH. The increased afterload leads to right ventricular dysfunction and failure. Multimodality imaging of the heart plays a central role in the diagnostic work-up and follow-up of patients with PH-LHD. Echocardiography provides information about the estimated pulmonary artery pressure, morphology and function of the left and right side of the heart, and valvular abnormalities. Cardiac magnetic resonance imaging is the gold standard for volumetric measurements and provides myocardial tissue characterisation. Computed tomography of the thorax may show general features of PH and/or LHD and is helpful in excluding other PH causes. Histopathology reveals a spectrum of pre- and post-capillary vasculopathy, including intimal fibrosis, media smooth muscle cell hyperplasia, adventitial fibrosis and capillary congestion. In this paper, we provide an overview of clinical, imaging and histopathological findings in PH-LHD based on three clinical cases.

Predictive value of soluble suppression of tumorigenicity 2 in atrial fibrillation: a systematic review and meta-analysis

Purpose

Atrial fibrosis is the main pathological basis for the pathogenesis and progression of atrial fibrillation (AF). Soluble suppression of tumorigenicity 2 (sST2) is involved in fibrosis. Recent studies have explored its predictive value in AF outcomes. We performed this study to assess whether sST2 is an independent biomarker of AF outcomes and explore the potential mechanism.

Methods

PubMed, Web of Science, EMBASE, and Cochrane Library databases were searched systematically from inception through July 1, 2023, to identify relevant studies. Outcomes of interest included occurrence, recurrence, and major adverse cardiac events (MACEs) of AF. This meta-analysis was reported following the criteria outlined in PRISMA 2020, and the protocol was registered in PROSPERO (number: CRD42023459789). All statistical analyses were performed using the STATA version 16.

Result

Twenty four studies with 14,755 patients were included in the meta-analysis. The meta-analyses found that sST2 was significantly associated with the risk of occurrence [HR:1.04, 95% CI: 1.02-1.07, P < 0.01; I2 = 67.8%], recurrence [HR:1.09, 95% CI: 1.02-1.16, P < 0.01; I2 = 89.5%], and MACEs (HR:1.60, 95% CI: 1.13-2.27, P < 0.01; I2 = 82.0%) of AF. Furthermore, patients with AF showed higher sST2 than controls without AF (SMD: 0.41, 95% CI: 0.27-0.54, P < 0.01; I2 = 0%), and AF patients with recurrence after catheter ablation (CA) showed significantly higher sST2 than those without recurrence (SMD: 0.81, 95% CI: 0.33-1.28, P < 0.01; I2 = 83.9%). Sensitivity analyses showed that the outcomes were stable.

Conclusions

Higher sST2 was association with an increased risk of occurrence, recurrence, and MACEs of AF. Assessing sST2 can be used as a potential screening method to predict AF outcomes.

Systematic Review Registration

PROSPERO (CRD42023459789).

Left atrial strain, embolic stroke of undetermined source, and atrial fibrillation detection

BACKGROUND

Atrial cardiopathy is a proposed mechanism of embolic stroke of undetermined source (ESUS). Left atrial (LA) strain may identify early atrial cardiopathy prior to structural changes. We aim to study the associations between LA strain, ESUS, and atrial fibrillation (AF) detection in ESUS.

METHODS

The study population included patients with ESUS and noncardioembolic (NCE) stroke presenting to the Rhode Island Hospital Stroke Center between January 2016 and June 2017 who underwent transthoracic echocardiography. Speckle tracking echocardiography (STE) was used to measure the three phases of LA strain (reservoir, conduit, and contractile). Binary logistic regression analysis was performed to determine the associations between LA strain and stroke subtype (ESUS vs. NCE) as well as follow-up detection of AF in ESUS patients.

RESULTS

We identified 656 patients, 307 with ESUS and 349 with NCE. In binary logistic regression, the lowest tertiles of LA reservoir (adjusted OR 1.944, 95% CI 1.266-2.986, p = .002), contractile (aOR 1.568, 95% CI 1.035-2.374, p = .034), and conduit strain (aOR 2.288, 95% CI 1.448-3.613, p = .001) were more likely to be significantly associated with ESUS compared to NCE stroke. Among all ESUS patients, the lowest tertiles of LA reservoir strain (OR 2.534, 95% CI 1.029-6.236, p = .043), contractile strain (OR 2.828, 95% CI 1.158-6.903, p = .022), and conduit strain (OR 2.614, 95% CI 1.003-6.815, p = .049) were significantly associated with subsequent detection of AF.

CONCLUSION

Reduced LA strain is associated with ESUS occurrence and AF detection in ESUS patients. Therefore, quantification of LA strain in ESUS patients may improve risk stratification and guide secondary prevention strategies.

Unveiling the Multifaceted Problems Associated with Dysrhythmia

Dysrhythmia is a term referring to the occurrence of spontaneous and repetitive changes in potentials with parameters deviating from those considered normal. The term refers to heart anomalies but has a broader meaning. Dysrhythmias may concern the heart, neurological system, digestive system, and sensory organs. Ion currents conducted through ion channels are a universal phenomenon. The occurrence of channel abnormalities will therefore result in disorders with clinical manifestations depending on the affected tissue, but phenomena from other tissues and organs may also manifest themselves. A similar problem concerns the implementation of pharmacotherapy, the mechanism of which is related to the impact on various ion currents. Treatment in this case may cause unfavorable effects on other tissues and organs. Drugs acting through the modulation of ion currents are characterized by relatively low tissue specificity. To assess a therapy's efficacy and safety, the risk of occurrences in other tissues with similar mechanisms of action must be considered. In the present review, the focus is shifted prominently onto a comparison of abnormal electrical activity within different tissues and organs. This review includes an overview of the types of dysrhythmias and the basic techniques of clinical examination of electrophysiological disorders. It also presents a concise overview of the available pharmacotherapy in particular diseases. In addition, the authors review the relevant ion channels and their research technique based on patch clumping.

Genetic Atrial Cardiomyopathies: Common Features, Specific Differences, and Broader Relevance to Understanding Atrial Cardiomyopathy

Atrial cardiomyopathy is a condition that causes electrical and contractile dysfunction of the atria, often along with structural and functional changes. Atrial cardiomyopathy most commonly occurs in conjunction with ventricular dysfunction, in which case it is difficult to discern the atrial features that are secondary to ventricular dysfunction from those that arise as a result of primary atrial abnormalities. Isolated atrial cardiomyopathy (atrial-selective cardiomyopathy [ASCM], with minimal or no ventricular function disturbance) is relatively uncommon and has most frequently been reported in association with deleterious rare genetic variants. The genes involved can affect proteins responsible for various biological functions, not necessarily limited to the heart but also involving extracardiac tissues. Atrial enlargement and atrial fibrillation are common complications of ASCM and are often the predominant clinical features. Despite progress in identifying disease-causing rare variants, an overarching understanding and approach to the molecular pathogenesis, phenotypic spectrum, and treatment of genetic ASCM is still lacking. In this review, we aim to analyze the literature relevant to genetic ASCM to understand the key features of this rather rare condition, as well as to identify distinct characteristics of ASCM and its arrhythmic complications that are related to specific genotypes. We outline the insights that have been gained using basic research models of genetic ASCM in vitro and in vivo and correlate these with patient outcomes. Finally, we provide suggestions for the future investigation of patients with genetic ASCM and improvements to basic scientific models and systems. Overall, a better understanding of the genetic underpinnings of ASCM will not only provide a better understanding of this condition but also promises to clarify our appreciation of the more commonly occurring forms of atrial cardiomyopathy associated with ventricular dysfunction.

Clinical presentation, management, and survival in dogs with persistent atrial standstill in the United Kingdom

OBJECTIVES

To investigate the clinical and echocardiographic presentation of dogs with persistent atrial standstill (PAS), identify variables measured at first presentation that could predict their survival, and document the progression of the disease after pacing.

MATERIALS AND METHODS

Retrospective study of medical records of dogs diagnosed with PAS at three referral hospitals of the United Kingdom over seven years.

RESULTS

Twenty-six dogs were diagnosed with PAS during the study period. Median age of the population was three years (range: 7 months-12.5 years). The most common clinical sign was syncope (14/26). Twenty-four dogs received artificial pacemakers (PM). Major complications after PM implantation were observed in four dogs (4/24). Serial echocardiographic examinations showed that cardiac dimensions of PAS dogs with left atrial or left ventricular dilation at first presentation did not return to reference range after pacing. Further dilation of the cardiac chambers, recurrence of congestive heart failure (CHF), or development of new episodes of CHF were documented in 7, 4, and 10 PAS dogs, respectively, despite pacing. Median survival time for cardiac-related deaths after PM implantation was 1512 days (18-3207). Neither CHF nor echocardiographic variables at presentation predicted survival after PM implantation in PAS dogs.

CONCLUSIONS

PAS is an uncommon bradyarrhythmia, occurring in young adult dogs. Affected dogs were often presented with syncope. Whilst syncope resolved, cardiac remodeling persisted after PM implantation. Long-term survival was favorable after PM implantation and was not predicted by congestive status or cardiac chamber size at first presentation.

Heart Failure, Female Sex, and Atrial Fibrillation Are the Main Drivers of Human Atrial Cardiomyopathy: Results From the CATCH ME Consortium

BACKGROUND

Atrial cardiomyopathy (atCM) is an emerging prognostic factor in cardiovascular disease. Fibrotic remodeling, cardiomyocyte hypertrophy, and capillary density are hallmarks of atCM. The contribution of etiological factors and atrial fibrillation (AF) to the development of differential atCM phenotypes has not been quantified. This study aimed to evaluate the association between histological features of atCM and the clinical phenotype.

METHODS AND RESULTS

We examined left atrial (LA, n=95) and right atrial (RA, n=76) appendages from a European cohort of patients undergoing cardiac surgery. Quantification of histological atCM features was performed following wheat germ agglutinin/CD31/vimentin staining. The contributions of AF, heart failure, sex, and age to histological characteristics were determined with multiple linear regression models. Persistent AF was associated with increased endomysial fibrosis (LA: +1.13±0.47 μm, P=0.038; RA: +0.94±0.38 μm, P=0.041), whereas total extracellular matrix content was not. Men had larger cardiomyocytes (LA: +1.92±0.72 μm, P<0.001), while women had more endomysial fibrosis (LA: +0.99±0.56 μm, P=0.003). Patients with heart failure showed more endomysial fibrosis (LA: +1.85±0.48 μm, P<0.001) and extracellular matrix content (LA: +3.07±1.29%, P=0.016), and a higher capillary density (LA: +0.13±0.06, P=0.007) and size (LA: +0.46±0.22 μm, P=0.044). Fuzzy k-means clustering of histological features identified 2 subtypes of atCM: 1 characterized by enhanced endomysial fibrosis (LA: +3.17 μm, P<0.001; RA: +2.86 μm, P<0.001), extracellular matrix content (LA: +3.53%, P<0.001; RA: +6.40%, P<0.001) and fibroblast density (LA: +4.38%, P<0.001), and 1 characterized by cardiomyocyte hypertrophy (LA: +1.16 μm, P=0.008; RA: +2.58 μm, P<0.001). Patients with fibrotic atCM were more frequently female (LA: odds ratio [OR], 1.33, P=0.002; RA: OR, 1.54, P=0.004), with persistent AF (LA: OR, 1.22, P=0.036) or heart failure (LA: OR, 1.62, P<0.001). Hypertrophic features were more common in men (LA: OR=1.33, P=0.002; RA: OR, 1.54, P=0.004).

CONCLUSIONS

Fibrotic atCM is associated with female sex, persistent AF, and heart failure, while hypertrophic features are more common in men.

Early Remodeling of the Left Atrium Following Catheter Ablation of Atrial Fibrillation: Insights From DECAAFII

BACKGROUND

Left atrial (LA) enlargement is prevalent among atrial fibrillation (AF) patients and constitutes an important marker of atrial myopathy. Several studies have described reduction in LA volume post-catheter ablation (CA) of AF, however, none have investigated differences related to additional ablation outside the pulmonary veins (PVs).

OBJECTIVES

The authors sought to study early LA remodeling following CA of persistent AF and the impact of additional, fibrosis-guided extra-PV ablation.

METHODS

In this DECAAF II (Effect of MRI-Guided Fibrosis Ablation vs Conventional Catheter Ablation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation) trial subanalysis, patients with persistent AF were randomized to receive pulmonary vein isolation (PVI) only or PVI + fibrosis-guided ablation. Late gadolinium enhancement magnetic resonance imaging (LGE-MRI) was performed before and 3 months after CA. Patients were followed up with single-lead electrocardiogram devices for 12 to18 months. AF burden was calculated as days with AF divided by days monitored.

RESULTS

This analysis included 733 patients. The mean LA volume index (LAVI) before ablation was 62.0 mm3/m2 and after ablation was 51.3 mm3/m2, with a mean reduction of 10.7 mm3/m2 (P < 0.001). Patients in the fibrosis-guided ablation arm had more volume reduction than did those in the PVI-only group (12.1 mm3/m2 vs 9.3 mm3/m2; P = 0.02). LAVI reduction was greater in patients with heart failure (15.7 vs 8.9; P = 0.001) and was associated with improved left ventricular ejection fraction (LVEF) (r = 0.23; P < 0.001), reduced AF burden (r = -0.173; P < 0.001), improved LVEF, and improved quality of life (r = 0.146; P < 0.001).

CONCLUSIONS

We confirmed the presence of LA remodeling within 3 months after ablation for persistent AF. Importantly, we saw more LA volume reductions in patients in the PVI + fibrosis-guided ablation arm in comparison with PVI only, and in patients with LV dysfunction. LA volume reduction in response to CA is associated with decreased arrhythmia recurrence, reduced AF burden, and improved LVEF and quality of life.

Incremental Effect of Mitral Regurgitation on Left Atrial Dysfunction and Atrioventricular Interaction in Hypertensive Patients by MRI

BACKGROUND

Mitral regurgitation may occur when hypertension causes left ventricular (LV) and left atrial (LA) remodeling. However, its role in LA function in hypertensive patients remains unclear.

PURPOSE

To explore how mitral regurgitation affects LA function in hypertension and to investigate atrioventricular interaction in hypertensive patients with mitral regurgitation.

STUDY TYPE

Retrospective.

POPULATION

A total of 193 hypertensive cases and 64 controls.

FIELD STRENGTH/SEQUENCE

A 3.0 T/balanced steady-state free precession.

ASSESSMENT

LA volume (LAV), LA strain (reservoir, conduit, and active), LA ejection fraction, and LV strain (global peak longitudinal [GLS], circumferential [GCS], and radial strain [GRS]) were evaluated and compared among groups. Regurgitant fraction (RF) was evaluated in regurgitation patients and used to subdivide patients into mild (RF: 0%-30%), moderate (RF: 30%-50%), and severe (RF: >50%) regurgitation categories.

STATISTICAL TESTS

One-way analysis of variance, Spearman and Pearson's correlation coefficients (r), and multivariable linear regression analysis. A P value <0.05 was considered statistically significant.

RESULTS

Hypertensive patients without mitral regurgitation showed significantly impaired LA reservoir and conduit functions and significantly decreased LV GLS but preserved pump function and LAV compared to controls (P = 0.193-1.0). Hypertensive cases with mild regurgitation (N = 22) had significantly enlarged LAV and further reduced LA reservoir function, while the group with moderate regurgitation (N = 20) showed significantly reduced LA pump function, further impaired conduit function, and significantly reduced LV strain. The severe regurgitation (N = 13) group demonstrated significantly more severely impaired LA and LV functions and LAV enlargement. Multivariable linear regression showed that regurgitation degree, GRS, GCS, and GLS were independently correlated with the LA reservoir, conduit, and active strain in hypertensive patients with mitral regurgitation.

DATA CONCLUSION

Mitral regurgitation may exacerbate LA and LV impairment in hypertension. Regurgitation degree, LV GRS, GCS, and GLS were independent determinants of the LA strain in hypertensive patients with mitral regurgitation, which demonstrated atrioventricular interaction.

EVIDENCE LEVEL

4.

TECHNICAL EFFICACY

Stage 3.

Influence of exercise training on the left atrium: implications for atrial fibrillation, heart failure, and stroke

The left atrium (LA) plays a critical role in receiving pulmonary venous return and modulating left ventricular (LV) filling. With the onset of exercise, LA function contributes to the augmentation in stroke volume. Due to the growing focus on atrial imaging, there is now evidence that structural remodeling and dysfunction of the LA is associated with adverse outcomes including incident cardiovascular disease. In patients with established disease, pathological changes in atrial structure and function are associated with exercise intolerance, increased hospital admissions and mortality, independent of left ventricular function. Exercise training is widely recommended in patients with cardiovascular disease to improve patient outcomes and maintain functional capacity. There are widely documented changes in LV function with exercise, yet less attention has been given to the LA. In this review, we first describe LA physiology at rest and during exercise, before exploring its association with cardiac disease outcomes including atrial fibrillation, heart failure, and stroke. The adaptation of the LA to short- and longer-term exercise training is evaluated through review of longitudinal studies of exercise training in healthy participants free of cardiovascular disease and athletes. We then consider the changes in LA structure and function among patients with established disease, where adverse atrial remodeling may be implicated in the disease process. Finally, we consider important future directions for assessment of atrial structure and function using novel imaging modalities, in response to acute and chronic exercise.

Cardiac Fibrosis in heart failure: Focus on non-invasive diagnosis and emerging therapeutic strategies

Heart failure is a leading cause of mortality and hospitalization worldwide. Cardiac fibrosis, resulting from the excessive deposition of collagen fibers, is a common feature across the spectrum of conditions converging in heart failure. Eventually, either reparative or reactive in nature, in the long-term cardiac fibrosis contributes to heart failure development and progression and is associated with poor clinical outcomes. Despite this, specific cardiac antifibrotic therapies are lacking, making cardiac fibrosis an urgent unmet medical need. In this context, a better patient phenotyping is needed to characterize the heterogenous features of cardiac fibrosis to advance toward its personalized management. In this review, we will describe the different phenotypes associated with cardiac fibrosis in heart failure and we will focus on the potential usefulness of imaging techniques and circulating biomarkers for the non-invasive characterization and phenotyping of this condition and for tracking its clinical impact. We will also recapitulate the cardiac antifibrotic effects of existing heart failure and non-heart failure drugs and we will discuss potential strategies under preclinical development targeting the activation of cardiac fibroblasts at different levels, as well as targeting additional extracardiac processes.

Accurate Classification of Non-ischemic Cardiomyopathy

PURPOSE OF REVIEW

This article aims to review the accurate classification of non-ischemic cardiomyopathy, including the methods, basis, subtype characteristics, and prognosis, especially the similarities and differences between different classifications.

RECENT FINDINGS

Non-ischemic cardiomyopathy refers to a myocardial disease that excludes coronary artery disease or ischemic injury and has a variety of etiologies and high incidence. Recent studies suggest that traditional classification methods based on primary/mixed/acquired or genetic/non-genetic cannot meet the precise needs of contemporary clinical management. This article systematically describes the history of classifications of cardiomyopathy and presents etiological and genetic differences between cardiomyopathies. The accurate classification is described from the perspective of morphology, function, and genomics in hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, left ventricular noncompaction, and partially acquired cardiomyopathy. The different clinical characteristics and treatment needs of these cardiomyopathies are elaborated. Some single-gene mutant cardiomyopathies have unique phenotypes, and some cardiomyopathies have mixed phenotypes. These special classifications require personalized precision treatment, which is worthy of independent research. This article describes recent advances in the accurate classification of non-ischemic cardiomyopathy from clinical phenotypes and causative genes, discusses the advantages and usage scenarios of each classification, compares the differences in prognosis and patient management needs of different subtypes, and summarizes common methods and new exploration directions for accurate classification.

Left atrial area index provides the best prediction of atrial fibrillation in ischemic stroke patients: results from the LAETITIA observational study

Background and aims

Left atrial (LA) enlargement has been repeatedly shown to be associated with the diagnosis of atrial fibrillation (AF). In clinical practice, several parameters are available to determine LA enlargement: LA diameter index (LADI), LA area index (LAAI), or LA volume index (LAVI). We investigated the predictive power of these individual LA parameters for AF in patients with acute ischemic stroke or transient ischemic attack (TIA).

Methods

LAETITIA is a retrospective observational study that reflects the clinical reality of acute stroke care in Germany. Consecutive patient cases with acute ischemic cerebrovascular event (CVE) in 2019 and 2020 were identified from the Mannheim stroke database. Predictive power of each LA parameter was determined by the area under the curve (AUC) of receiver operating characteristic curves. A cutoff value was determined. A multiple logistic regression analysis was performed to confirm the strongest LA parameter as an independent predictor of AF in patients with acute ischemic CVE.

Results

A total of 1,910 patient cases were included. In all, 82.0% of patients had suffered a stroke and 18.0% had a TIA. Patients presented with a distinct cardiovascular risk profile (reflected by a CHA2DS2-VASc score ≥2 prior to hospital admission in 85.3% of patients) and were moderately affected on admission [median NIHSS score 3 (1; 8)]. In total, 19.5% of patients had pre-existing AF, and 8.0% were newly diagnosed with AF. LAAI had the greatest AUC of 0.748, LADI of 0.706, and LAVI of 0.719 (each p < 0.001 vs. diagonal line; AUC-LAAI vs. AUC-LADI p = 0.030, AUC-LAAI vs. AUC-LAVI p = 0.004). LAAI, increasing NIHSS score on admission, and systolic heart failure were identified as independent predictors of AF in patients with acute ischemic CVE. To achieve a clinically relevant specificity of 70%, a cutoff value of ≥10.3 cm2/m2 was determined for LAAI (sensitivity of 69.8%).

Conclusion

LAAI revealed the best prediction of AF in patients with acute ischemic CVE and was confirmed as an independent risk factor. An LAAI cutoff value of 10.3 cm2/m2 could serve as an inclusion criterion for intensified AF screening in patients with embolic stroke of undetermined source in subsequent studies.

Hypertensive Heart Disease: A Narrative Review Series-Part 2: Macrostructural and Functional Abnormalities

Hypertensive heart disease (HHD) remains a major global public health concern despite the implementation of new approaches for the management of hypertensive patients. The pathological changes occurring during HHD are complex and involve the development of structural and functional cardiac abnormalities. HHD describes a broad spectrum ranging from uncontrolled hypertension and asymptomatic left ventricular hypertrophy (LVH), either a concentric or an eccentric pattern, to the final development of clinical heart failure. Pressure-overload-induced LVH is recognised as the most important predictor of heart failure and sudden death and is associated with an increased risk of cardiac arrhythmias. Cardiac arrhythmias are considered to be one of the most important comorbidities affecting hypertensive patients. This is the second part of a three-part set of review articles. Here, we focus on the macrostructural and functional abnormalities associated with chronic high pressure, their involvement in HHD pathophysiology, and their role in the progression and prognosis of HHD.

Pulmonary vein flow split effects in patient-specific simulations of left atrial flow

Disruptions to left atrial (LA) blood flow, such as those caused by atrial fibrillation (AF), can lead to thrombosis in the left atrial appendage (LAA) and an increased risk of systemic embolism. LA hemodynamics are influenced by various factors, including LA anatomy and function, and pulmonary vein (PV) inflow conditions. In particular, the PV flow split can vary significantly among and within patients depending on multiple factors. In this study, we investigated how changes in PV flow split affect LA flow transport, focusing for the first time on blood stasis in the LAA, using a high-fidelity patient-specific computational fluid dynamics (CFD) model. We use an Immersed Boundary Method, simulating the flow in a fixed, uniform Cartesian mesh and imposing the movement of the LA walls with a moving Lagrangian mesh generated from 4D Computerized Tomography images. We analyzed LA anatomies from eight patients with varying atrial function, including three with AF and either a LAA thrombus or a history of Transient Ischemic Attacks (TIAs). Using four different flow splits (60/40% and 55/45% through right and left PVs, even flow rate, and same velocity through each PV), we found that flow patterns are sensitive to PV flow split variations, particularly in planes parallel to the mitral valve. Changes in PV flow split also had a significant impact on blood stasis and could contribute to increased risk for thrombosis inside the LAA, particularly in patients with AF and previous LAA thrombus or a history of TIAs. Our study highlights the importance of considering patient-specific PV flow split variations when assessing LA hemodynamics and identifying patients at increased risk for thrombosis and stroke. This knowledge is relevant to planning clinical procedures such as AF ablation or the implementation of LAA occluders.

Effects of Rhythm Control for Atrial Fibrillation on Cardiac Remodeling and Valvular Regurgitation in Patients with Heart Failure

PURPOSE

Previous studies investigating cardiac remodeling and functional regurgitation of rhythm control for atrial fibrillation (AF) in heart failure (HF) are limited. Therefore, this study aimed to evaluate the impact of rhythm control for AF on cardiac remodeling and functional regurgitation in the spectrum of HF. Its effect on prognosis was explored.

METHODS

According to the treatment strategies of AF, the cohort was classified into the rhythm control and rate control groups. To further detect the implications of rhythm control on cardiac remodeling, functional regurgitation, and outcomes in HF subtypes, patients were further divided into HF with reduced ejection fraction (HFrEF), HF with mildly reduced ejection fraction, and HF with preserved ejection fraction (HFpEF) subgroups.

RESULTS

A total of 828 patients were enrolled, with 307 patients in the rhythm control group and 521 patients in the rate control group. Over a median follow-up time of 3.8 years, patients with rhythm control treatments experienced improvements in biatrial structure parameters, left ventricular ejection fraction, and functional regurgitation (mitral and tricuspid regurgitation) compared with rate control treatment (p < 0.05). Cox regression analysis demonstrated that rhythm control reduced the risks of all-cause mortality (HR 0.436 [95% CI, 0.218-0.871], p = 0.019) in HFpEF and HF-related admissions in HFrEF (HR 0.500 [95% CI, 0.330-0.757], p = 0.001) and HFpEF (HR 0.541 [95% CI, 0.407-0.720], p < 0.001); these associations were similar after adjusting for multiple confounders.

CONCLUSIONS

Rhythm control therapy can be considered an appropriate treatment strategy for the management of AF in HF to improve cardiac remodeling, functional regurgitation, and prognosis.

Brady- and tachyarrhythmias detected by continuous rhythm monitoring in paroxysmal atrial fibrillation

OBJECTIVE

Atrial fibrillation (AF) is associated with adverse events including conduction disturbances, ventricular arrhythmias and sudden death. The aim of this study was to examine brady- and tachyarrhythmias using continuous rhythm monitoring in patients with paroxysmal self-terminating AF (PAF).

METHODS

In this multicentre observational substudy to the Reappraisal of Atrial Fibrillation: interaction between hyperCoagulability, Electrical remodelling and Vascular destabilisation in the progression of AF (RACE V), we included 392 patients with PAF and at least 2 years of continuous rhythm monitoring. All patients received an implantable loop recorder, and all detected episodes of tachycardia ≥182 beats per minute (BPM), bradycardia ≤30 BPM or pauses ≥5 s were adjudicated by three physicians.

RESULTS

Over 1272 patient-years of continuous rhythm monitoring, we adjudicated 1940 episodes in 175 patients (45%): 106 (27%) patients experienced rapid AF or atrial flutter (AFL), pauses ≥5 s or bradycardias ≤30 BPM occurred in 47 (12%) patients and in 22 (6%) patients, we observed both episode types. No sustained ventricular tachycardias occurred. In the multivariable analysis, age >70 years (HR 2.3, 95% CI 1.4 to 3.9), longer PR interval (HR 1.9, 1.1-3.1), CHA2DS2-VASc score ≥2 (HR 2.2, 1.1-4.5) and treatment with verapamil or diltiazem (HR 0.4, 0.2-1.0) were significantly associated with bradyarrhythmia episodes. Age >70 years was associated with lower rates of tachyarrhythmias.

CONCLUSIONS

In a cohort exclusive to patients with PAF, almost half experienced severe bradyarrhythmias or AF/AFL with rapid ventricular rates. Our data highlight a higher than anticipated bradyarrhythmia risk in PAF.

TRIAL REGISTRATION NUMBER

NCT02726698.

Echocardiographic Evaluation of Atrial Remodelling for the Prognosis of Maintaining Sinus Rhythm after Electrical Cardioversion in Patients with Atrial Fibrillation

Atrial fibrillation (AF) is the most common atrial tachyarrhythmia. One of the methods of AF treatment is direct current cardioversion (DCCV), but in the long-term follow-up we observe quite a high percentage of AF recurrences after this procedure. In order to assess the prognosis of DCCV effectiveness, we use clinical, biochemical and echocardiographic parameters. The objective of this review is to systematise the current knowledge on echocardiographic measurements in patients with persistent AF used to assess the progress of remodelling of the atrial wall, which affects the likelihood of maintaining sinus rhythm after DCCV. In this article, echocardiographic parameters for the evaluation of remodelling of the atrial wall are divided into groups referring to structural, mechanical, and electrical remodelling, as well as parameters for the evaluation of left ventricular filling pressure. The article aims to draw attention to the clinical value of echocardiographic measurements, which is the selection of patients who will maintain sinus rhythm after DCCV in the long-term follow-up, which will allow to avoid unnecessary risks associated with the procedure and enable the selection of the appropriate treatment strategy.

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.