Upstream Therapy for Atrial Fibrillation Prevention: The Role of Sacubitril/Valsartan

Factors predicting the recurrence of atrial fibrillation after catheter ablation: A review

Atrial fibrillation (AF) is the most common and clinically significant type of cardiac arrhythmia. Although catheter ablation (CA) can restore sinus rhythm in patients with AF, some patients experience recurrence after the procedure. This requires us to find a simple and effective way to identify patients at a high risk of recurrence and to intervene early in the high-risk population to improve patient prognosis. The mechanism of AF recurrence is unclear, but it involves several aspects including patient history, inflammation, myocardial fibrosis, and genes. This article summarizes the current predictors of AF recurrence after CA, including myocardial fibrosis markers, inflammatory markers, MicroRNAs, Circular RNAs, AF recurrence scores, and imaging indicators. Each predictor has its own scope of application, and the predictive capacity and joint application of multiple predictors may improve the predictive power. In addition, we summarize the mechanisms involved in AF recurrence. We hope that this review will assist researchers understand the current predictors of AF recurrence and help them conduct further related studies.

GLP-1 receptor agonists and myocardial metabolism in atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia. Many medical conditions, including hypertension, diabetes, obesity, sleep apnea, and heart failure (HF), increase the risk for AF. Cardiomyocytes have unique metabolic characteristics to maintain adenosine triphosphate production. Significant changes occur in myocardial metabolism in AF. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have been used to control blood glucose fluctuations and weight in the treatment of type 2 diabetes mellitus (T2DM) and obesity. GLP-1RAs have also been shown to reduce oxidative stress, inflammation, autonomic nervous system modulation, and mitochondrial function. This article reviews the changes in metabolic characteristics in cardiomyocytes in AF. Although the clinical trial outcomes are unsatisfactory, the findings demonstrate that GLP-1 RAs can improve myocardial metabolism in the presence of various risk factors, lowering the incidence of AF.

Sacubitril/valsartan attenuates atrial conduction disturbance and electrophysiological heterogeneity with ameliorating fibrosis in mice

Background

Sacubitril/valsartan (SacVal) has been shown to improve the prognosis of heart failure; however, whether SacVal reduces the occurrence of atrial fibrillation (AF) in heart failure has not yet been elucidated. In this study, we aimed to determine whether SacVal is effective in reducing the occurrence of AF in heart failure and identify the underlying mechanism of its electrophysiological effect in mice.

Methods

Adult male mice underwent transverse aortic constriction, followed by SacVal, valsartan, or vehicle treatment for two weeks. Electrophysiological study (EPS) and optical mapping were performed to assess the susceptibility to AF and the atrial conduction properties, and fibrosis was investigated using heart tissue and isolated cardiac fibroblasts (CFs).

Results

EPS analysis revealed that AF was significantly less inducible in SacVal-treated mice than in vehicle-treated mice. Optical mapping of the atrium showed that SacVal-treated and valsartan-treated mice restored the prolonged action potential duration (APD); however, only SacVal-treated mice showed the restoration of decreased conduction velocity (CV) compared to vehicle-treated mice. In addition, the electrophysiological distribution analysis demonstrated that heterogeneous electrophysiological properties were rate-dependent and increased heterogeneity was closely related to the susceptibility to AF. SacVal attenuated the increased heterogeneity of CV at short pacing cycle length in atria, whereas Val could not. Histological and molecular evaluation showed that SacVal exerted the anti-fibrotic effect on the atria. An in vitro study of CFs treated with natriuretic peptides and LBQ657, the metabolite and active form of sacubitril, revealed that C-type natriuretic peptide (CNP) combined with LBQ657 had an additional anti-fibrotic effect on CFs.

Conclusions

Our results demonstrated that SacVal can improve the conduction disturbance and heterogeneity through the attenuation of fibrosis in murine atria and reduce the susceptibility of AF in heart failure with pressure overload, which might be attributed to the enhanced function of CNP.

Sacubitril/valsartan reduces susceptibility to atrial fibrillation by improving atrial remodeling in spontaneously hypertensive rats

AIM

Sacubitril/valsartan (Sac/Val, LCZ696), the world's first angiotensin receptor-neprilysin inhibitor (ARNi), has been widely used in the treatment of heart failure. However, the use of Sac/Val in the treatment of atrial fibrillation (AF), especially AF with hypertension, has been less reported. We investigated the effect of Sac/Val on atrial remodeling and hypertension-related AF.

METHODS

The AF induction rate and electrophysiological characteristics of spontaneously hypertensive rats (SHRs) treated with Sac/Val or Val were detected by rapid atrial pacing and electrical mapping/optical mapping. The whole-cell patch-clamp and western blot were used to observe electrical/structural remodeling of atrial myocytes/tissue of rats and atrium-derived HL-1 cells cultured under 40 mmHg in vitro.

RESULTS

Sac/Val was superior to Val in reducing blood pressure, myocardial hypertrophy and susceptibility of AF in SHRs. The shorten action potentials duration (APD), decreased L type calcium channel current (I_Ca,L) and Cav1.2, increased ultrarapid delayed rectified potassium current (I_kur) and Kv1.5 in atrial myocytes/tissue of SHRs could be better improved by Sac/Val, as well as the levels of atrial fibrosis. While the protein expression of angiotensin-converting enzyme-1 (ACE-1), angiotensin, angiotensin II type I AT1 receptor (AT1R) and neprilysin (NEP) were increased, which could be more effective ameliorated by Sac/Val than Val. Furthermore, Val + Sacubitrilat (LBQ657) (an active NEP inhibitor) was also superior to LBQ657 or Val in improving the electrical and structural remodeling of HL-1 cells through inhibiting NEP.

CONCLUSION

Sac/Val can improve atrial structural and electrical remodeling induced by hypertension and reduce the AF susceptibility by inhibiting RAS and NEP. The above effects of Sac/Val were superior to Val alone.

The impact of sacubitril/valsartan on outcome in patients suffering from heart failure with a concomitant diabetes mellitus

BACKGROUND

Guidelines classify sacubitril/valsartan as a significant part of medical treatment of heart failure with reduced ejection fraction (HFrEF). Data have shown that the HbA1c levels in patients with diabetes mellitus could be impacted by sacubitril/valsartan. A possible positive effect in diabetes patients treated with sacubitril/valsartan on outcome and echocardiography parameters is not well studied yet.

AIMS

The aim of the present study was to compare the impact of sacubitril/valsartan on life-threatening arrhythmias, atrial fibrillation, different echocardiography parameters and congestion rate in patients suffering from HFrEF according to the diagnosis diabetes mellitus or no diabetes mellitus.

METHODS AND RESULTS

Consecutive 240 patients with HFrEF from 2016 to 2020 were treated with sacubitril/valsartan and separated to concomitant diabetes mellitus (n = 87, median age 68 years interquartile range (IQR) [32-87]) or no diabetes mellitus (n = 153, median age 66 year IQR [34-89]). Different comorbidities and outcome data were evaluated over a follow-up period of 24 months. Arterial hypertension (87% vs. 64%; P < 0.01) and coronary artery disease (74% vs. 60%; P = 0.03) were more often documented in patients with diabetes mellitus compared with patients without diabetes mellitus. Over the follow-up of 24 months several changes were noted in both subgroups: Median left ventricular ejection fraction (EF) increased significantly in non-diabetes (27% IQR [3-44] at baseline to 35% IQR [13-64]; P < 0.001), but not in diabetic patients (29% IQR [10-65] at baseline to 30% IQR [13-55]; P = 0.11). Accordingly, NT-proBNP and troponin-I levels decreased significantly in non-diabetes patients (NT-brain natriuretic peptide [NT-proBNP] from median 1445 pg/mL IQR [12.6-74 676] to 491 pg/mL IQR [13-4571]; P < 0.001, troponin-I levels from 0.099 ng/mL IQR [0.009-138.69] to 0.023 ng/mL IQR [0.006-0.635]; P < 0.001), but not in diabetic patients (NT-proBNP from 1395 pg/mL IQR [100-29 924] to 885 pg/mL IQR [159-4331]; P = 0.06, troponin-I levels from 0.05 ng/mL IQR [0.013-103.0] to 0.020 ng/mL IQR [0.015-0.514]; P = 0.27). No significant change of laboratory parameters e. g. glomerular filtration rate, potassium level and creatinine levels were found in diabetes or non-diabetes patients. Comparing further echocardiography data, left atrial surface area, right atrial surface area, E/A ratio did not show a significant change either in the diabetes or non-diabetes group. However, the tricuspid annular plane systolic excursion was significantly increased in non-diabetes mellitus patients (from 17 mm IQR [3-31] to 18 mm [2.5-31]; P = 0.04), and not in diabetic s patients (17.5 mm IQR [8-30] to 18 mm IQR [14-31]; P = 0.70); the systolic pulmonary artery pressure remained unchanged in both groups. During follow-up, a similar rate of ventricular tachyarrhythmias was observed in both groups. The congestion rate decreased significantly in both groups, in diabetes patients (44.4% before sacubitril/valsartan and 13.5% after 24 months treatment; P = 0.0009) and in non-diabetic patients (28.4% before sacubitril/valsartan and 8.4% after 24 months treatment; P = 0.0004). The all-cause mortality rate was higher in patients with diabetes mellitus as compared with those without diabetes (25% vs. 8.1%; P < 0.01).

CONCLUSIONS

Sacubitril/valsartan reverses cardiac remodelling in non-diabetes patients. However, it reduces the congestion rate in diabetes and non-diabetes patients. The rates of ventricular tachyarrhythmias were similar in DM compared with non-DM over follow-up. The mortality rate remained to be over follow-up higher in diabetes patients compared with non-diabetes; however, it was lower compared with published data on diabetes and concomitant HFrEF not treated with sacubitril/valsartan.

Sacubitril/Valsartan Cannot Improve Cardiac Function Compared with Valsartan in Patients Suffering Nonvalvular Atrial Fibrillation without Systolic Heart Failure

This study investigates the effect of sacubitril/valsartan (Sac/Val) in patients diagnosed with nonvalvular atrial fibrillation (AF) without systolic heart failure (SHF).Nonvalvular AF patients without SHF admitted to the People's Hospital of Bortala Mongol Autonomous Prefecture from December 2020 to December 2021 were enrolled and randomly divided into Sac/Val treatment group (group T) and valsartan treatment group (group C, control). For subgroup analysis, patients were divided into subgroups with and without diastolic heart failure (DHF). After 1-month adaptive phase and subsequent 3-month treatment period, patients were followed up in the cardiology clinic. Plasma levels of biochemical markers and echocardiographic parameters before and after treatment were evaluated, and DHF scores were computed to assess diastolic function.Of 61 enrolled patients, 46 patients completed follow-up. Sac/Val treatment did not increase the percentage of sinus rhythm. Although N-terminal pro-B-type natriuretic peptide (NT-proBNP) expression tended to be reduced in both groups after 3 months of treatment, the differences compared with respective baseline levels and between groups were not significant. According to subgroup analysis, although NT-proBNP expression in the subgroup with DHF was lower at follow-up compared to baseline, the difference was not statistically significant. Similarly, no marked differences in echocardiographic parameters or tissue Doppler parameters related to DHF were detected between the groups (P > 0.05). Additionally, a subgroup analysis found no significant variations in the echocardiographic measures (P > 0.05).Sac/Val is not superior to valsartan for the short-term treatment of patients suffering with AF without SHF in improving NT-proBNP level and cardiac function.

Effect of angiotensin receptor-neprilysin inhibitor on atrial electrical instability in atrial fibrillation

Background and objective

Around 33.5 million patients suffered from atrial fibrillation (AF), causing complications and increasing mortality and disability rate. Upstream treatment for AF is getting more popular in clinical practice in recent years. The angiotensin receptor-neprilysin inhibitor (ARNI) is one of the potential treatment options. Our study aimed to investigate the effect of ARNI on atrial electrical instability and structural remodeling in AF.

Methods

Our research consisted of two parts - a retrospective real-world clinical study and an animal experiment on calmness to verify the retrospective founding. In the retrospective study, we reviewed all patients (n = 110) who had undergone the first AF ablation from 1 August 2018 to 1 March 2022. Patients with ARNI (n = 36) or angiotensin II receptor antagonist (ARB) (n = 35) treatment were enrolled. Their clinical data, ultrasound cardiogram (UCG) and Holter parameters were collected before radiofrequency catheter ablation (RFCA) as baseline and at 24-week follow-up. Univariate and multivariate logistic regression analysis were performed. In the animal experiment, we established an AF model (n = 18) on canines by rapid atrial pacing. After the successful procedure of pacing, all the 15 alive beagles were equally and randomly assigned to three groups (n = 5 each): Control group, ARB group, and ARNI group. UCG was performed before the pacing as baseline. Physiological biopsy, UCG, and electrophysiological study (EPS) were performed at 8-week.

Results

Clinical data showed that the atrial arrhythmia rate at 24-week was significantly lower in ARNI group compared to ARB group (P < 0.01), and ARNI was independently associated with a lower atrial arrhythmia rate (P < 0.05) at 24-week in multivariate regression logistic analysis. In the animal experiment, ARNI group had a higher atrial electrical stability score and a shorter AF duration in the EPS compared to Control and ARB group (P < 0.05). In the left atrium voltage mapping, ARNI group showed less low voltage and disordered zone compared to Control and ARB group. Compared to Control group, right atrium diameter (RAD), left ventricle end-diastolic volume index (LVEDVI), E/A, and E/E' were lower in ARNI group (P < 0.05) at the 8-weeks follow-up, while left atrium ejection fraction (LAEF) and left ventricle ejection fraction (LVEF) were higher (P < 0.01). Compared to ARB group, LVEF was higher in ARNI group at the 8-week follow-up (P < 0.05). ARB and ARNI group had a lower ratio of fibrotic lesions in the left atrium tissues compared to Control group (P < 0.01), but no difference was found between the ARB and the ARNI group.

Conclusion

ARNI could reduce atrial electrical instability in AF in comparison with ARB in both retrospective study and animal experiment.

Sacubitril/valsartan in Heart Failure and Beyond-From Molecular Mechanisms to Clinical Relevance

As the ultimate pathophysiological event, heart failure (HF) may arise from various cardiovascular (CV) conditions, including sustained pressure/volume overload of the left ventricle, myocardial infarction or ischemia, and cardiomyopathies. Sacubitril/valsartan (S/V; formerly termed as LCZ696), a first-in-class angiotensin receptor/neprilysin inhibitor, brought a significant shift in the management of HF with reduced ejection fraction by modulating both renin-angiotensin-aldosterone system (angiotensin II type I receptor blockage by valsartan) and natriuretic peptide system (neprilysin inhibition by sacubitril) pathways. Besides, the efficacy of S/V has been also investigated in the setting of other CV pathologies which are during their pathophysiological course and progression deeply interrelated with HF. However, its mechanism of action is not entirely clarified, suggesting other off-target benefits contributing to its cardioprotection. In this review article our goal was to highlight up-to-date clinical and experimental evidence on S/V cardioprotective effects, as well as most discussed molecular mechanisms achieved by this dual-acting compound. Although S/V was extensively investigated in HF patients, additional large studies are needed to elucidate its effects in the setting of other CV conditions. Furthermore, with its antiinflamatory potential, this agent should be investigated in animal models of inflammatory heart diseases, such as myocarditis, while it may possibly improve cardiac dysfunction as well as inflammatory response in this pathophysiological setting. Also, discovering other signalling pathways affected by S/V should be of particular interest for basic researches, while it can provide additional understanding of its cardioprotective mechanisms.

Effect of Sacubitril-Valsartan on Restoration and Maintenance of Sinus Rhythm in Patients With Persistent Atrial Fibrillation

Background

Existing studies have shown that sacubitril-valsartan ameliorated atrial remodeling in atrial fibrillation (AF) and favored maintenance of sinus rhythm in patients with AF and heart failure. However, the effect of sacubitril-valsartan in patients with persistent AF is yet unknown. We aimed to evaluate the effect of sacubitril-valsartan on restoration and maintenance of sinus rhythm in patients with persistent AF who underwent electrical cardioversion (ECV).

Method

Consecutive patients with persistent AF who underwent ECV between 1 January 2016 and 30 September 2020 were investigated in this retrospective cohort study. All eligible patients were categorized into sacubitril-valsartan users and sacubitril-valsartan non-users based on whether they received treatment with sacubitril-valsartan or not. The endpoint was ineffictive ECV, defined as the composite of failure to terminate AF or any recurrence of AF during 30 days follow-up.

Results

A total of 76 patients were enrolled in this study, including 28 sacubitril-valsartan users and 48 non-users. Within a follow-up of 30 days after ECV, the endpoint had occurred in 7 (25%) of 28 sacubitril-valsartan users and 25 (52%) of 48 non-users. Significantly lower rate of ineffictive ECV in sacubitril-valsartan users compared with non-users was shown in Kaplan-Meier survival curves (P = 0.02; Log-rank test). Multivariate Cox regression analysis indicated that sacubitril-valsartan use (hazard ratio [HR], 0.35; 95% confidence interval [CI], 0.14–0.91), amiodarone use (HR, 0.32; 95% CI, 0.13–0.78), left atrial diameter ≤ 39 mm (HR, 0.21; 95% CI, 0.06–0.71) were independently associated with a decreased rate of ineffective electrical cardioversion.

Conclusion

Use of sacubitril-valsartan is associated with a significantly decreased risk of ineffective ECV compared with non-users in patients with persistent AF.

Angiotensin receptor blocker neprilysin inhibitors

Heart failure (HF) is a clinical syndrome that results from a structural or functional cardiac disorder that reduces the ability of the ventricle of the heart to fill with, or eject, blood. It is a multifaceted clinical condition that affects up to 2% of the population in the developed world, and is linked to significant morbidity and mortality; it is therefore considered a major concern for public health. Regarding the mechanism of HF, three neurohumoral factors - the renin-angiotensin-aldosterone system, the sympathetic nervous system, and natriuretic peptides - are related to the pathology of chronic HF (CHF), and the targets of treatment. Angiotensin receptor blocker and neprilysin inhibitor (angiotensin-receptor neprilysin inhibitor), namely sacubitril/valsartan (SAC/VAL), has been introduced as a treatment for CHF. SAC/VAL is an efficacious, safe, and cost-effective therapy that improves quality of life and longevity in patients with HF with reduced ejection fraction (HFrEF), and reduces hospital admissions. An in-hospital initiation strategy offers a potential new avenue to improve the clinical uptake of SAC/VAL. In the last five years, SAC/VAL has been established as a cornerstone component of comprehensive disease-modifying medical therapy in the management of chronic HFrEF. On the other hand, further work, with carefully designed and controlled preclinical studies, is necessary for understanding the molecular mechanisms, effects, and confirmation of issues such as long-term safety in both human and animal models.