Cardiac Remodeling, Circulating Biomarkers and Clinical Events in Patients with a History of Atrial Fibrillation. Data from the GISSI-AF Trial

Ameliorative Impact of Liraglutide on Chronic Intermittent Hypoxia-Induced Atrial Remodeling

Atrial fibrillation (AF) is the most frequent form of clinical cardiac arrhythmias. Previous evidence proved that atrial anatomical remodeling (AAR) and atrial electrical remodeling (AER) are crucial for the progression and maintenance of AF. This study is aimed at investigating the impact of the glucagon-like peptide-1 (GLP-1) receptor agonist, Liraglutide (Lir), on atrial remodeling (AR) mouse model induced by chronic intermittent hypoxia (CIH). C57BL/6 mice were categorized randomly into the control, Lir, CIH, and CIH+Lir groups. CIH was performed in CIH and CIH+Lir groups for 12 weeks. Lir (0.3 mg/kg/day, s.c) was administered to the Lir and CIH+Lir groups for four weeks, beginning from the ninth week of CIH. Meanwhile, echocardiography and right atrial endocardial electrophysiology via jugular vein, as well as induction rate and duration of AF, were evaluated. Masson and Sirius red staining assays were utilized to assess the extent of fibrosis in the atrial tissue of the mice. Immunohistochemical staining, RT-qPCR, and Western blotting were performed to evaluate the marker levels of AAR and AER and the expression of genes and proteins of the miR-21/PTEN/PI3K/AKT signaling pathway, respectively. ELISA was also performed to evaluate the changes of serum inflammatory factor levels. The CIH group exhibited significant AR, increased atrial fibrosis, and a higher incidence rate of AF compared to the control group. Lir could significantly downregulate the protein expression level in the PI3K/p-AKT pathway and upregulated that of phosphatase and tensin homolog deleted on chromosome ten (PTEN). Moreover, Lir downregulated the expression of miR-21. However, the protein expressions of CACNA1C and KCNA5 in atrial tissue were not changed significantly. In addition, Lir significantly attenuated the levels of markers of inflammation (TNF-α and IL-6) in the serum. In the mouse model of CIH, Lir treatment could ameliorate AR by the miR-21/PTEN/PI3K/AKT signaling pathway and modulation of inflammatory responses.

Influencing Factors of Recurrence of Nonvalvular Atrial Fibrillation after Radiofrequency Catheter Ablation and Construction of Clinical Nomogram Prediction Model

PURPOSE

This study sought to investigate the predictive factors for atrial fibrillation (AF) recurrence in patients after radiofrequency ablation (RFCA) and construct a nomogram prediction model for providing precious information of ablative strategies.

METHODS

A total of 221 patients with AF who underwent RFCA were enrolled. Univariate and multivariate Cox regression were used to screen the predictors of recurrence. The receiver operating characteristic (ROC) curve and the Kaplan-Meier (K-M) curve were drawn to analyze the value of predictors. The nomogram model was further constructed to predict the recurrence of AF in patients after RFCA.

RESULTS

There were 59 cases of AF recurrence after RFCA. Monocyte count/high-density lipoprotein cholesterol (MHR), AF course (COURSE), coronary heart disease (CHD), and AF type (TYPE) were the independent risk factors for predicting AF recurrence after RFCA. Accordingly, a nomogram prediction model based on MHR, COURSE, CHD, and TYPE was constructed with a C-index of 0.818 (95% CI: 0.681∼0.954), while the C-index of verification was 0.802 (95% CI: 0.658∼0.946).

CONCLUSIONS

Preoperative MHR, COURSE, CHD, and TYPE were independent risk factors for predicting recurrence of AF after RFCA. The nomogram model based on MHR, COURSE, CHD, and TYPE can be used to predict the recurrence of AF after RFCA accurately and individually.

Angiotensin Receptor Blocker and Calcium Channel Blocker Preventing Atrial Fibrillation Recurrence in Patients with Hypertension and Atrial Fibrillation: A Meta-analysis

Background

Atrial fibrillation (AF) is the most common serious cardiac rhythm disturbances and is responsible for substantial morbidity and mortality in general population. Hypertension is the most prevalent and potentially modifiable risk factor for AF. This study is aimed at evaluating the effect of angiotensin receptor blocker (ARB) or calcium channel blocker (CCB) on AF recurrence among patients with hypertension and AF.

Methods

The PubMed, EMBASE, Medline, and Cochrane Collaboration of Controlled Clinical Trials registry databases were searched from their inception to September 2020.

Results

A total of 7 randomized controlled trials (RCTs) enrolling 1495 patients were included in our study. This finding showed that ARB had a statistically significant superiority in preventing AF recurrence (OR: 0.43, 95% CI: 0.30-0.72, P = 0.0006) and persistent AF (OR: 0.41, 95% CI: 0.24-0.71, P = 0.001) compared to CCB. Subgroup analysis showed that there was a significant difference in telmisartan subgroup (OR: 0.54, 95% CI: 0.23-1.29, P = 0.17) and nontelmisartan subgroup (OR: 0.42, 95% CI: 0.23-0.77, P = 0.005). Subgroup analysis indicated that nifedipine subgroup did not show a statistically significant difference on AF recurrence between ARB and CCB (OR: 0.88, 95% CI: 0.46-1.68, P = 0.69), but amlodipine subgroup showed that ARB had a significant superiority in prevention of AF recurrence (OR: 0.39, 95% CI: 0.27-0.56, P < 0.0001) compared with CCB.

Conclusions

This study suggests that ARB is superior to CCB for preventing the AF recurrence and persistent AF among patients with hypertension and AF.

Association of clinical predictors with recurrence of atrial fibrillation after catheter ablation

BACKGROUND

Recurrence rate after radiofrequency catheter ablation (RFCA) remains high, and further investigation on predictors of recurrence is needed.

OBJECTS

To identify risk factors of atrial fibrillation (AF) recurrence in patients undergoing RFCA.

METHODS

We retrospectively studied 257 patients with AF who underwent RFCA preceded by transthoracic echocardiographic and pulmonary vein CT examination from 2016 to 2019. Electrocardiogram examination was performed at baseline, 1, 3, 6 months, and 1 year after RFCA. We divided patients into two groups based on AF recurrence including recurrence group (n = 79) and nonrecurrence group (n = 178). The crude and independent association between clinical variables and AF recurrence was evaluated with logistic regression analysis. Specificity and positive predictive value of relevant factors for AF recurrence were performed by ROC curve.

RESULTS

Of these AF patients, 174 (68%) was paroxysmal AF and 83 (32%) was persistent AF. The multivariate logistic regression demonstrated that AF duration (OR = 1.008, 95% CI 1.002-1.013, p = .008), pulmonary arterial hypertension (PAH; OR = 2.313, 95% CI 1.031-5.192, p = .042), and low-density lipoprotein cholesterol (LDL-C; OR = 1.646, 95% CI 1.129-2.398, p = .010) were independently correlated with recurrence of AF. For predicting AF recurrence, the specificity and sensitivity of AF duration were 30.1% and 87.3%, and for LDL-C, the specificity and sensitivity of AF duration were 60.6% and 60.5%, respectively.

CONCLUSIONS

Atrial fibrillation duration, PAH, and LDL-C might be independent risk factors for the recurrence of AF after RFCA.

Attenuation of atrial remodeling by aliskiren via affecting oxidative stress, inflammation and PI3K/Akt signaling pathway

INTRODUCTION

Atrial fibrillation (AF) is the most common type of arrhythmia. Atrial remodeling is a major factor to the AF substrate. The purpose of the study is to explore whether aliskiren (ALS) has a cardioprotective effect and its potential molecular mechanisms on atrial remodeling.

METHODS

In acute experiments, dogs were randomly assigned to Sham, Paced and Paced+aliskiren (10 mg kg^-1) (Paced+ALS) groups, with 7 dogs in each group. Rapid atrial pacing (RAP) was maintained at 600 bpm for 2 h for paced and Paced+ALS groups and atrial effective refractory periods (AERPs), inducibility of AF (AFi) and average duration time (ADT) were measured. In chronic experiments, there were 5 groups: Sham, Sham+ALS, Paced, Paced+ALS and Paced+ALS+PI3K antagonist wortmannin (WM) (70 μg kg^-1 day^-1). RAP at 500 beats/min was maintained for 2 weeks. Inflammation and oxidative stress indicators were measured by ELISA assay, echocardiogram and pathology were used to assess atrial structural remodeling, phosphatidylinositol 3-hydroxy kinase/protein kinase B (PI3K/Akt) signaling pathways were studied by RT-PCR and western blotting to evaluate whether the cardioprotective effect of ALS works through PI3K/Akt signaling pathway.

RESULTS

The electrophysiological changes were observed after 2-h pacing. The AERP shortened with increased AFi and ADT, which was attenuated by ALS (P < 0.05). After pacing for 2 weeks, oxidative stress and inflammation markers in the Paced group were significantly higher than those in the Sham group (P < 0.01) and were reduced by ALS treatment (P < 0.01). The reduced level of antioxidant enzymes caused by RAP was also found to be elevated in ALS-treated group (P < 0.01). The results of pathology and echocardiography showed that RAP can cause atrial enlargement, fibrosis (P < 0.01), and were attenuated in ALS treatment group. The PI3K/Akt signaling pathway were downregulated induced by RAP. ALS could upregulate the PI3K/Akt pathway expression (P < 0.05). Furthermore, the cardioprotective effects in structural remodeling of ALS were suppressed by WM.

CONCLUSIONS

ALS may offer cardioprotection in RAP-induced atrial remodeling, which may partly be ascribed to its anti-inflammatory and anti-oxidative stress action and the regulation of PI3K/Akt signaling pathway.

Inflammatory Cytokines During Cardiac Rehabilitation After Heart Surgery and Their Association to Postoperative Atrial Fibrillation

Inflammation is associated with atrial fibrillation (AF), but little is known about the association of AF with the inflammatory serum cytokines after the acute postoperative phase. Thus, we aimed to explore how plasma cytokines concentrations modify during a 3-week cardiac rehabilitation after heart surgery, comparing patients who developed postoperative AF (POAF) and those with permanent AF with patients free from AF (NoAF group). We enrolled 100 consecutive patients and 40 healthy volunteers as a control group. At the beginning of cardiac rehabilitation, 11 days after surgery, serum levels of MPO, PTX3, ADAM17, sST2, IL-25, and IL-33 were dramatically higher, whereas TNFα and IL-37 levels were much lower in NoAF, POAF, and permanent AF patients than in the healthy volunteers. After rehabilitation, most of the cytokines changed tending towards normalization. POAF patients (35% of the total) had higher body mass index and abdominal adiposity than NoAF patients, but similar general characteristics and risk factors for POAF. However, ADAM-17 and IL-25 were always lower in POAF than in NoAF patients, suggesting a protective role of IL-25 and ADAM 17 against POAF occurrence. This finding could impact on therapeutic strategies focusing on the postoperative prophylactic antiarrhythmic interventions.

Prevalence and Incidence of Atrial Fibrillation in Ambulatory Patients With Heart Failure

Heart failure (HF) and atrial fibrillation (AF) commonly co-exist. We aimed to determine the prevalence and incidence of AF in ambulatory patients with HF. HF was defined by the presence of symptoms or signs supported by objective evidence of cardiac dysfunction: either a left ventricular ejection fraction (LVEF) ≤45% (HF and a reduced ejection fraction, HFrEF), or LVEF >45% and a raised plasma concentration of amino-terminal pro-B type natriuretic peptide (NT-proBNP >220 ng/L; HFpEF). Of 3,570 patients with HF, 1,164 were in AF at baseline (33%), with a higher prevalence among patients with HFpEF compared with HFrEF (40% vs 26%, respectively, p <0.001). Compared with patients with HF in sinus rhythm, those in AF were older, had more severe symptoms and higher NT-proBNP, worse renal function, and were more likely to receive loop diuretics, despite having a higher LVEF. Of those in sinus rhythm, 1,372 patients had HFrEF and 1,034 had HFpEF. The incidence of AF at 1 year (3.0%) was similar for each phenotype (p = 0.73). Increasing age, male gender, history of paroxysmal AF, and higher plasma concentrations of NT-proBNP were independent predictors of incident AF during a median follow-up of 1,574 (interquartile range: 749 to 2,821) days; the predictors were similar for each phenotype. In conclusion, the prevalence of AF is high, especially in patients with HFpEF, but its incidence is modest. This may be because their onset is near simultaneous with the development of AF precipitating the onset of HF.

The Same is Not the Same: Device Effect during Bipolar Radiofrequency Ablation of Atrial Fibrillation

BACKGROUND

Different ablation devices deliver the same type of energy but use individual control mechanisms to estimate efficacy. We compared patient outcome after the application of radiofrequency ablation systems, using temperature- or resistance-control in paroxysmal and persistent atrial fibrillation (AF).

METHODS

This is an unselected all-comers study. Patients underwent standardized left atrial (paroxysmal atrial fibrillation, [PAF] n = 31) or biatrial ablation (persistent atrial fibrillation [persAF] n = 61) with bipolar RF from October 2010 to June 2013. Patients with left atrial dilatation (up to 57 mm), reduced left ventricular (LV) function, and elderly were included. We used resistance-controlled (RC) or temperature-controlled (TC) devices. We amputated atrial appendices and checked intraoperatively for completeness of pulmonary vein exit block. All patients received implantable loop recorders. Follow-up interval was every 6 months. Antiarrhythmic medical treatment endured up to month 6.

RESULTS

We reached 100% freedom from atrial fibrillation (FAF) in PAF. In perAF 19% of the RC but 82% of the TC patients reached FAF (12 months; p < 0.05). TC patients exhibited higher creatine kinase-muscle/brain (CK-MB) peak values. In persAF, CK-MB-levels correlated to FAF. No and no mortality (30 days) was evident. Twelve-month mortality did not correlate to AF type, AF duration, LV dimension, or function and age. Prolonged need of oral anticoagulants was 90.1% (RC) and 4.5% (TC).

CONCLUSION

In patients with persAF undergoing RF ablation, TC reached higher FAF than RC. Medical devices are not "the same" regarding effectiveness even if used according to manufacturer's instructions. Thus, putative application of "the same" energy is not always "the same" efficacy.

Immunopathogenesis and biomarkers of recurrent atrial fibrillation following ablation therapy in patients with preexisting atrial fibrillation

INTRODUCTION

Recurrent atrial fibrillation (RAF) following ablation therapy occurs in about 50% of patients. The pathogenesis of RAF is unknown, but is believed to be driven by atrial remodeling in the setting of background inflammation. Structural, electrophysiological and mechanical remodeling has been associated with atrial fibrillation (AF). Inflammation and fibrotic remodeling are the major factors perpetuating AF, as mediators released from the atrial tissues and cardiomyocytes due to mechanical and surgical injury could initiate the inflammatory process. In this article, we have critically reviewed the key mediators that may serve as potential biomarkers to predict RAF. Areas covered: Damage associated molecular patterns, heat shock proteins, inflammatory cytokines, non-inflammatory markers, markers of inflammatory cell activity, and markers of collagen deposition and metabolism are evaluated as potential biomarkers with molecular treatment options in RAF. Expert commentary: Establishing biomarkers to predict RAF could be useful in reducing morbidity and mortality. Investigations into the role of DAMPs participating in a sterile immune response may provide greater insight into the pathogenesis of RAF. Markers evaluating immune cell activity, collagen deposition, and levels of heat shock proteins show the greatest promise as potential biomarkers to predict RAF and develop novel therapies.

Apelin: A novel prognostic predictor for atrial fibrillation recurrence after pulmonary vein isolation

Apelin, the ligand for the APJ receptor, is involved in the pathogenesis of atrial fibrillation (AF). However, whether serum apelin can predict the recurrence of AF after pulmonary vein isolation (PVI) has not been determined.A prospective cohort study was performed in patients with AF (but without structural heart disease) who were undergoing first-time PVI. Serum apelin-12 was measured by enzyme-linked immunosorbent assay. Echocardiographic examination was performed at baseline, 3 months, and 6 months after PVI. Patients were followed up for 6 months after PVI, and the association between baseline apelin-12 and AF recurrence (early recurrence: within 3 months after ablation; late recurrence: 3-6 months after ablation) was analyzed.A total of 61 patients were included in the study. Baseline serum level of apelin-12 was significant lower in patients with early (median [interquartile range]: 1844 [1607-2061] vs 2197 [1895-2455] ng/L, P = .01) and late (1639 [1524-1853] vs 1923 [1741-2303] ng/L, P = .02) AF recurrence compared with patients without these events. Results of Cox stepwise multivariate analysis demonstrated that lower baseline apelin-12 (<2265 ng/L) was independently associated with increased AF recurrence within 6 months after PVI (P < .05). The specificity and positive predictive value of apelin-12 for AF recurrence were significantly higher than those of baseline N-terminal brain proBNP (60.4% vs 28.6%, P < .001; 58.8% vs 34.4%, P = .01), although the sensitivity and negative predictive value were similar.Reduced baseline serum apelin-12 may be an independent risk factor for the recurrence of AF after PVI in patients without structural heart disease.