Losartan and Prevention of Atrial Fibrillation Recurrence in Hypertensive Patients

Meta-analysis of renin angiotensin aldosterone modulators mitigating Atrial Fibrillation risk in hypertensive patients

INTRODUCTION

Hypertension is associated with left ventricular hypertrophy/enlargement/fibrosis and atrial ectopic rhythm, leading to an increased risk of Atrial Fibrillation (AF). We aimed to stratify the effect of Angiotensin Converting Enzyme Inhibitors (ACEi) and Angiotensin Receptor Blockers (ARB) on the risk of AF.

METHODS

PubMed, Scopus, and Google Scholar databases were screened, and cross-citation was conducted for studies reporting AF in hypertensive patients on ACEi and ARB. Of 145 studies found till May 2023, 19 were included in this study. Binary random-effects models estimated the pooled odds ratios, I2 statistics assessed heterogeneity and sensitivity analysis was assessed using the leave-one-out method.

RESULTS

153,559 hypertensive patients met the inclusion criteria. For incidental AF, ACEi and ARB showed a significant decrease in both unadjusted (OR 0.75, 95% CI [0.66-0.85], I² = 20.79%, p=0.29) and adjusted risks (OR 0.76, 95% CI [0.62-0.93], I² = 88.41%, p<0.01). In recurrent AF, the unadjusted analysis showed no significant effect (OR 0.89, 95% CI [0.55-1.42], I² = 78.44%, p<0.01), while the adjusted analysis indicated a reduced risk (OR 0.62, 95% CI [0.50-0.76], I² = 65.71%, p<0.01). Leave-one-out sensitivity analysis confirmed these results.

CONCLUSIONS

ACEi and ARB considerably decrease the risk of incidental and recurrent AF in hypertensive patients, emphasizing the importance of treating clinical hypertension with these drugs.

Time-varying serum uric acid predicts new-onset atrial fibrillation in treated hypertensive patients. The LIFE Study

Aim: The Losartan Intervention For Endpoint reduction in hypertension (LIFE) Study showed less new-onset atrial fibrillation (AF) in hypertensive patients receiving losartan- vs. atenolol-based treatment. Because losartan reduces serum uric acid (SUA) levels, the aim of the present study was to investigate relations of SUA with new-onset AF in the study. Methods: Hypertensive patients with electrocardiographic (ECG) left ventricular hypertrophy (LVH) and no prior AF (n = 8,243) were treated for 5.0 ± 0.4 years with losartan- or atenolol-based therapy. Associations of SUA with new-onset AF documented by Minnesota coding were assessed by Cox models using SUA and systolic blood pressure as time-varying covariates to take into account changes of SUA related to losartan or diuretic treatment, changes in renal function, and aging. Results: Time-varying SUA was associated with new AF defined by Minnesota code [hazard ratio (HR) = 1.19 per 16.8 μmol/L (1 mg/dL), (95% confidence intervals (CIs), 1.12–1.26), P < 0.0001], independent of losartan treatment [HR = 0.75 (95% CIs, 0.61–0.93), P = 0.007], older age [HR = 1.95 per 7.0 years (95% CIs, 1.73–2.20), P < 0.0001], male sex [HR = 1.46 (95% CIs, 1.09–1.94), P = 0.010] and higher Cornell voltage-duration product [HR = 1.10 per 1,023 ms·mm (95% CIs, 1.01–1.21), P = 0.034]. Similar results were obtained in Cox models with SUA levels partitioned according to baseline quartiles and in which AF was defined by physician reports or by both Minnesota coding and physician reports. Conclusions: In-treatment SUA is a strong predictor for new-onset AF in hypertensive patients, independent of effects of antihypertensive treatment, age, sex, and ECG-LVH. Further research is needed to clarify how uric acid may provoke AF (ClinicalTrials.gov identifier: NCT00338260).

Atrial Fibrillation and Hypertension: "Quo Vadis"

Hypertension is one of the most well-established risk factors for atrial fibrillation. Long-standing untreated hypertension leads to structural remodeling and electrophysiologic alterations causing an atrial myopathy that forms a vulnerable substrate for the development and maintenance of atrial fibrillation. Hypertension-induced hemodynamic, inflammatory, hormonal, and autonomic changes all appear to be important contributing factors. Furthermore, hypertension is also associated with several atrial fibrillation-related comorbidities. As such, hypertension may represent an important target for therapy in atrial fibrillation. Clinicians should be aware of pitfalls of the blood pressure measurement in atrial fibrillation. While the auscultatory method is preferred, the use of automated devices appears to be an acceptable method in the ambulatory setting. There are pathophysiologic bases and emerging clinical evidence suggesting the benefit of renin-angiotensin system inhibition in risk reduction of atrial fibrillation development particularly in patients with left ventricular hypertrophy or left ventricular dysfunction. A better understanding of hypertension's pathophysiologic link to atrial fibrillation may lead to the development of novel therapies for the primary prevention of atrial fibrillation. Finally, future studies are needed to address optimal blood pressure goal to minimize the risk of atrial fibrillation-related complications.

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.

Angiotensin II and angiotensin 1-7: which is their role in atrial fibrillation?

Atrial fibrillation (AF) is a significant cause of morbidity and mortality as well as a public health burden considering the high costs of AF-related hospitalizations. Pre-clinical and clinical evidence showed a potential role of the renin angiotensin system (RAS) in the etiopathogenesis of AF. Among RAS mediators, angiotensin II (AII) and angiotensin 1-7 (A1-7) have been mostly investigated in AF. Specifically, the stimulation of the pathway mediated by AII or the inhibition of the pathway mediated by A1-7 may participate in inducing and sustaining AF. In this review, we summarize the evidence showing that both RAS pathways may balance the onset of AF through different biological mechanisms involving inflammation, epicardial adipose tissue (EAT) accumulation, and electrical cardiac remodeling. EAT is a predictor for AF as it may induce its onset through direct (infiltration of epicardial adipocytes into the underlying atrial myocardium) and indirect (release of inflammatory adipokines, the stimulation of oxidative stress, macrophage phenotype switching, and AF triggers) mechanisms. Classic RAS blockers such as angiotensin converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARB) may prevent AF by affecting the accumulation of the EAT, representing a useful therapeutic strategy for preventing AF especially in patients with heart failure and known left ventricular dysfunction. Further studies are necessary to prove this benefit in patients with other cardiovascular diseases. Finally, the possibility of using the A1-7 or ACE2 analogues, to enlarge current therapeutic options for AF, may represent an important field of research.

Left atrial longitudinal strain by speckle tracking as independent predictor of recurrence after electrical cardioversion in persistent and long standing persistent non-valvular atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia in humans. After successful cardioversion, there is a recurrence of 60% due to atrial remodeling, and it has been shown that the global peak atrial longitudinal strain (GPALS) is decreased in these subjects. The aim of this study was to evaluate the predictive value of GPALS for AF recurrence. A prospective cohort of patients with persistent (PnVAF) and long standing persistent non-valvular AF (LSPnVAF) which underwent electrical cardioversion was evaluated with standard echocardiographic variables and GPALS quantification. The primary endpoint was AF recurrence at 6 months. We included PnVAF (n = 50, aged 68.4 ± 10.2 years, female 46%, lasted AF 6 months) and LSPnVAF (n = 81, aged 66.5 ± 13.1 years, female 36%, lasted AF 18 months). At 6 months there were a 68% of recurrence of AF in PnVAF and 53% in LSPnVAF group. GPALS was lower in recurrence 7.8 ± 2.0% versus 21.2 ± 8.9% (p < 0.001) for PnVAF and 7.3 ± 2.7% versus 20.7 ± 7.6% (p < 0.001) in LSPnVAF. GPALS ≤ 10.75% discriminates recurrence at 6 months with a sensitivity of 85%, specificity 99%, PPV 85%, NPV 90%, LR + 8.5 and LR- 0.17. The independent predictors of recurrence in PnVAF were GPALS ≤ 10.75% HR 8.89 [(2.2-35.7), p < 0.01] meanwhile in LSPnVAF were age HR 1.039 [(1.007-1.071), p = 0.01], and GPALS ≤ 10.75% HR 28.1 [(7.2-109.1), p < 0.001]. In subjects with PnVAF and LSPnVAF with successful electrical cardioversion, GPALS ≤ 10.75% predicts arrhythmia recurrence at 6-month follow-up.

Biomarkers of Atrial Fibrillation: Which One Is a True Marker?

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmias and associated with the risk of stroke and death. Continuous development of the diagnostic tool and prognostic stratification may lead to optimal management of AF. The use of biomarkers in the management of AF has been grown as an interesting topic. However, the AF biomarkers are not yet well established in the major guidelines. Among these biomarkers, a lot of data show troponin and brain natriuretic peptides are promising for the prediction of future events. The troponin elevation in AF patients may not necessarily be diagnosed as myocardial infarction or significant coronary artery stenosis, and brain natriuretic peptide elevation may not necessarily confirm heart failure. Troponin T and troponin I may predict postoperative AF. Furthermore, troponin and brain natriuretic peptide gave better prognostic performance when compared with the risk score available today.

Study on the Effect of Irbesartan on Atrial Fibrillation Recurrence in Kumamoto: Atrial Fibrillation Suppression Trial (SILK study)

BACKGROUND

Experimental studies suggest that angiotensin II-receptor blockers can influence atrial remodeling and may prevent atrial fibrillation (AF). Therefore, we hypothesized that irbesartan may prevent the recurrence of AF following either catheter ablation or electrical cardioversion of AF.

METHODS

Study on the Effect of Irbesartan on Atrial Fibrillation Recurrence in Kumamoto (SILK study) is a prospective, multicenter, randomized, and open-label comparative evaluation of the effects of irbesartan and amlodipine on AF recurrence in hypertensive patients with AF who are scheduled to undergo catheter ablation or electrical cardioversion of AF. The primary end point was either AF or atrial tachycardia (AT) recurrence. AF/AT recurrence was evaluated for 6 months using 24-h Holter electrocardiogram and portable electrocardiogram. The secondary endpoints included the change in blood pressure, the interval from the procedure to the first AF/AT recurrence, cardiovascular events, left atrial diameter (LAD), left ventricular ejection fraction (LVEF), and changes in the biomarkers [brain natriuretic polypeptide (BNP), high-sensitivity C-reactive protein (hs-CRP), urinary albumin/creatinine].

RESULTS

The study enrolled 98 patients (irbesartan; n=47, amlodipine; n=51). The recurrence of AF/AT was observed in 8 patients (17.0%) in the irbesartan group and in 10 patients (19.6%) in the amlodipine group. There was no significant difference in the AF/AT recurrence between the irbesartan and amlodipine groups. Blood pressure decreased similarly in both groups. There were no significant differences between the two groups as regards to the interval from the procedure to the first AF/AT recurrence, occurrence of cardiovascular events, changes in LAD and LVEF. BNP and urinary albumin/creatinine significantly decreased similarly in both groups, but no significant difference was found in hs-CRP between the two groups.

CONCLUSIONS

In hypertensive patients with AF, treatment with irbesartan did not have any advantage over amlodipine in the reduction of AF/AT recurrence after catheter ablation or electrical cardioversion.

The Different Therapeutic Choices with ARBs. Which One to Give? When? Why?

The renin-angiotensin-aldosterone system plays an important role in the pathophysiology of hypertension and is closely related with cardio- and cerebrovascular events and chronic kidney diseases. Each angiotensin receptor blocker (ARB) is important in the treatment of hypertension, according to the results of recent years. This is a practical review of the available evidence on the different benefits of ARBs beyond their blood pressure-lowering effect, with an emphasis on the differences found between the particular compounds and the therapeutic implications of the findings, with specific reference to the co-morbidities.

Atrial fibrillation and arterial hypertension: A common duet with dangerous consequences where the renin angiotensin-aldosterone system plays an important role

Atrial fibrillation (AF) represents the most common sustained cardiac arrhythmia, as it affects 1%-2% of the general population and up to 15% of people over 80 years. High blood pressure, due to its high prevalence in the general population, is by far the most common condition associated with AF, although a variety of diseases, including valvular, coronary heart and metabolic diseases, are held to create the substrate favouring AF. Due to the concomitance of these conditions, it is quite challenging to dissect the precise role of high blood pressure in triggering/causing AF. Hence, even though the intimate association between high blood pressure and AF has been known for decades, the underlying mechanisms remain partially unknown. Accumulating evidences point to a major role of the renin-angiotensin-aldosterone system in inducing cardiac inflammation and fibrosis, and therefore electric and structural atrial and ventricular remodelling, with changes in ions and cell junctions leading to AF development. These evidences are herein reviewed with a particular emphasis to the role of the renin-angiotensin-system aldosterone system.

Prevention of atrial fibrillation with renin-angiotensin system inhibitors on essential hypertensive patients: a meta-analysis of randomized controlled trials

We aimed to investigate the effectiveness and safety of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) on preventing atrial fibrillation in essential hypertensive patients. Systematic literature retrieval was carried out to obtain randomized controlled trials on the effects of ACEI/ARBs on essential hypertensive patients before December, 2013. Data extraction and quality evaluation were performed. Meta-analysis was performed by Review Manager 5.2.3. Ten high quality studies (11 articles) with a total of 42,892 patients (20,491 patients in the ACEI/ARBs group and 22,401 patients in the β-blocker or the calcium antagonist group) met the inclusion criteria and were included in the meta-analysis. The results showed that ACEI/ARBs reduced the incidence of atrial fibrillation (AF) recurrence compared to calcium antagonists (RR = 0.48; 95%CI, 0.40-0.58; P<0.00001) or β-blockers (RR = 0.39; 95%CI, 0.20-0.74; P = 0.005) in long-term follow-up, respectively. Furthermore, ACEI/ARBs reduced the incidence of congestive heart failure (RR = 0.86; 95%CI, 0.77-0.96; P = 0.007). However, no significant effects were observed on the incidence of new AF, cardiac death, myocardial infarction, and stroke. Our results suggest that ACEI/ARBs may reduce the incidence of AF recurrence and congestive heart failure, with fewer serious adverse effects.

Renin-angiotensin system inhibitors prevent the recurrence of atrial fibrillation: a meta-analysis of randomized controlled trials

OBJECTIVE

This study was designed to assess whether angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) could prevent the recurrence of atrial fibrillation (AF).

METHODS

A systemic literature search of PubMed, EMBASE, and Cochrane Controlled Trials Register till 2012 was performed to identify randomized controlled trials involving the prevention of recurrence of AF with renin-angiotensin system blockade therapy. Subgroup analysis and meta-regression were performed. Publication bias was checked through funnel plot and Egger's test.

RESULTS

Twenty-one randomized controlled trials including 13,184 patients with AF were identified. Overall, the recurrence of AF was significantly reduced in patients using ACEI/ARBs [odds ratio (OR), 0.43; 95% confidence interval (CI), 0.32-0.56; P < 0.00001], especially both in irbesartan subgroup (OR, 0.38; 95% CI, 0.21-0.68; P = 0.001) and in patients receiving antiarrhythmic drug (AAD) (OR, 0.37; 95% CI, 0.29-0.48; P < 0.00001), and there was no significant difference between ACEIs and ARBs (ACEIs: OR, 0.42; 95% CI, 0.31-0.57 and ARBs: OR, 0.42; 95% CI, 0.31-0.57). Moreover, it was found that the benefits of ACEI/ARBs revealed positive correlation to systolic blood pressure (regression coefficient: -0.0700257, P = 0.000) in no-AAD users.

CONCLUSIONS

ACEI/ARBs are effective on the secondary prevention of AF, especially in patients receiving AAD and suffering from hypertension.

The Role Of Renin Angiotensin System In Atrial Fibrillation

Atrial fibrillation (AF) is the most prevalent arrhythmia and its incidence is on the rise. AF causes significant morbidity and mortality leading to rising AF-related health care costs. There is experimental and clinical evidence from animal and human studies that suggests a role for the renin angiotensin system (RAS) in the etiopathogenesis of AF. This review appraises the current understanding of RAS antagonism, using angiotensin converting enzyme inhibitors (ACE-I), angiotensin receptor blockers (ARB) and aldosterone antagonists (AA), for prevention of AF. RAS antagonism has proven to be effective for primary and secondary prevention of AF in subjects with heart failure and left ventricular (LV) dysfunction.However, most of the evidence for the protective effect of RAS antagonism is from clinical trials that had AF as a secondary outcome or from unspecified post-hoc analyses. The evidence for prevention in subjects without heart failure and with normal LV function is not as clear. RAS antagonism, in the absence of concomitant antiarrhythmic therapy, was not shown to reduce post cardioversion AF recurrences. RAS antagonism in subjects undergoing catheter ablation has also been ineffective in preventing AF recurrences.

Renin-angiotensin system inhibitors for prevention of recurrent atrial fibrillation: a meta-analysis

INTRODUCTION

Conflicting results exist now on the clinical utility of renin-angiotensin system (RAS) inhibitors in patients with atrial fibrillation (AF). This study aimed to elaborate the efficacy and safety of RAS blockade on preventing the relapse of AF by a meta-analysis based on randomised controlled trials (RCTs).

METHODS

We searched Medline, ISI web of science and Cochrane databases through Jan 2012. We included RCTs comparing RAS inhibition treatment vs. placebo or alternative therapy after cardioversion of persistent AF or conventional medical therapy for paroxysmal AF and reporting outcome of recurrent AF. Odds ratios (OR) were calculated using a random effects model.

RESULTS

Fifteen trials involving 3972 AF patients were included in the analysis. The pooling analysis showed that RAS inhibitors significantly reduced the recurrence of AF compared with non-RAS inhibitors (OR=0.50, 95% CI: 0.37-0.69, p<0.01), and the beneficial effect was shown consistently both in patients with paroxysmal and in those with persistent AF after cardoversion. However, administration of RAS inhibitors did not provide a greater survival advantage and a lower incidence of adverse effects than the control (OR=1.17, 95% CI, 0.65-2.10, p=0.59; OR=0.94, 95% CI: 0.65-1.35, p=0.73 respectively). In addition, clinical factors potentially affecting AF relapsing had no pronounced impacts on the above clinical outcomes.

CONCLUSIONS

Based on the currently available data, inhibition of RAS is effective, safe and well tolerated for preventing the recurrence of AF.

Effect of nifedipine versus telmisartan on prevention of atrial fibrillation recurrence in hypertensive patients

It is controversial whether angiotensin II receptor blockers provide better protection than calcium antagonists against atrial fibrillation (AF) recurrence in hypertensive patients. This study was designed to compare the effect of nifedipine- and telmisartan-based antihypertensive treatments for preventing AF recurrence in hypertensive patients with paroxysmal AF. A total of 149 hypertensive patients with paroxysmal AF were randomized to nifedipine- or telmisartan-based antihypertensive treatment groups. The target blood pressure (BP) was <130/80 mm Hg. Clinic BP, ECG, Holter monitoring, and echocardiography were followed up for 2 years. The primary end point was the incidence of overall and persistent AF recurrence. During follow-up, there was no statistical difference in the rate of patients lowering to target BP between both groups, whereas nifedipine group had slightly better BP control but similar heart rate control at 24 months. The incidence of AF recurrence was similar in both groups (nifedipine versus telmisartan: 58.7% versus 55.4%; P=0.742), and Kaplan-Meier analysis showed no significant difference in the freedom from AF recurrence (log-rank test; P=0.48). However, the rate of developing persistent AF in telmisartan group was lower than that in nifedipine group (5.4% versus 16.0%; P=0.035). Patients in telmisartan group had lower values of left atrial diameter, left atrial volume index, and left ventricular mass index at the end of follow-up. The effects of telmisartan in preventing AF recurrences in hypertensive patients with paroxysmal AF after intensive lowering BP is similar to that of nifedipine, but telmisartan has more potent effects on preventing progression to persistent AF.

Renin-angiotensin-system modulators and the incidence of atrial fibrillation following hospitalization for coronary artery disease

AIMS

Previous studies have suggested that upstream medical therapy to modulate the renin-angiotensin axis may facilitate left atrial remodelling and thereby prevent new-onset atrial fibrillation (AF). The purpose of this study was to evaluate the association between angiotensin converting enzyme inhibitor (ACEI) and angiotensin receptor blockers (ARB) on new-onset AF in a large cohort of patients with coronary artery disease (CAD).

METHODS AND RESULTS

This was a population-based study of 28 620 patients, from community-dwelling Medicare beneficiaries who had been hospitalized for acute myocardial infarction or coronary revascularization (1995-2004). All patients, 65 years and older, had a mean follow-up period of upto 3.8 ± 3.0 years. Patients with a history of AF before and during hospitalization were excluded. We compared the incidence of new-onset AF between patients who were (N= 10 918) and were not (N= 17 702) prescribed ACEI and/or ARB within 1 month of hospital discharge following cardiac event. New-onset AF within 5 and 10 years was 39.1 and 61.1%, respectively, in patients who received ACEI/ARB, compared 34.9 and 53.6% in patients who did not receive them [unadjusted hazard ratio (HR): 1.16; 95% confidence interval (CI): 1.11, 1.21]. Multivariable analysis adjusting for patient- and hospital-related characteristics indicated that ACEI/ARB use independently had no impact on the risk of developing new-onset AF compared with non-users (adjusted HR: 0.99; 95% CI: 0.94, 1.04). Adjustment for propensity-score and health-seeking behaviours yielded nearly identical results.

CONCLUSION

Angiotensin converting enzyme inhibitor/ARB therapy initiated within 1 month after hospital discharge is not associated with a reduction in the risk of new-onset AF after myocardial infarction or coronary revascularization.

Effect of telmisartan on paroxysmal atrial fibrillation recurrence in hypertensive patients with normal or increased left atrial size

BACKGROUND

Hypertension is the most prevalent and potentially modifiable risk factor for atrial fibrillation (AF). In a previous secondary prevention study, the authors observed that the angiotensin II receptor blocker telmisartan was more effective than the calcium channel blocker amlodipine in preventing AF relapse in hypertensive patients with normal atrial size.

HYPOTHESIS

Telmisartan may be more effective than amlodipine in preventing AF recurrence in hypertensive patients with paroxysmal AF and normal or increased left atrial dimension (LAD).

METHODS

The authors assigned 378 mild hypertensive outpatients in sinus rhythm, but with ≥2 episodes of AF in the previous 6 months, to 1 of 2 groups. Group 1 comprised patients with LAD <40 mm in females and <45 mm in males. Group 2 comprised patients with LAD >40 mm and <45 mm in females and >45 mm and <50 mm in males. In both groups, patients were randomly treated with telmisartan or amlodipine for 1 year.

RESULTS

Systolic and diastolic blood pressure were similarly reduced by telmisartan and amlodipine in both groups. The AF recurrence rate was significantly lower in the telmisartan-treated patients than in the amlodipine-treated patients in both group 1 (12 vs 39, P < 0.01) and group 2 (40 vs 59, P < 0.05). Under telmisartan, the AF recurrence rate was significantly lower in group 1 than in group 2 (12.9% vs 42.1%, P < 0.05). Time to a first AF relapse was significantly longer with telmisartan than with amlodipine in both group 1 (176 ± 94 days vs 74 ± 61 days, P < 0.05) and group 2 (119 ± 65 days vs 38 ± 35 days, P < 0.05).

CONCLUSIONS

Telmisartan was more effective than amlodipine in preventing AF recurrences in hypertensive patients with paroxysmal AF.

Renin-Angiotensin System and AtrialFibrillation:Understanding the Connection

Atrial fibrillation (AF) arises as a result of a complex interaction of triggers, perpetuators and the substrate. The recurrence of AF may be partially related to a biologic phenomenon known as remodeling, in which the electrical, mechanical, and structural properties of the atrial tissue and cardiac cells are progressively altered,creating a more favorable substrate. Atrial remodeling is in part a consequence of arrhythmia itself. Therefore,to prevent and to treat AF, much attention has been directed to upstream therapies to alter the arrhythmia substrate and to reduce atrial remodeling. The renin-angiotensin-aldosterone system (RAAS) plays a keyrole in these strategies. In this review we analyze the experimental and clinical evidence regarding the efficacy of RAAS inhibitors in AF treatment. In the primary prevention of AF, meta-analyses have shown that risk of new-onset AF in patients with congestive heart failure and left ventricular dysfunction is reduced by RAAS inhibitors, whereas in hypertensive and post-myocardial infarction patients, the results are less evident. In the secondary prevention of AF, some large, prospective, randomized, placebo-controlled studieswith angiotensin II-receptor blockers returned negative results. Unfortunately, the approach of using RAASinhibitors as antiarrhythmic drugs to prevent both new-onset and recurrent AF is in decline because negativetrial results are accumulating, with the exception of the results in patients with congestive heart failure.

Hypertension and atrial fibrillation: epidemiology, pathophysiology and therapeutic implications

Hypertension is one of the most important risk factors associated with atrial fibrillation (AF) and increased the risk of cardiovascular events in patients with AF. However, the pathophysiological link between hypertension and AF is unclear. Nevertheless, this can be explained by the hemodynamic changes of the left atrium secondary to long standing hypertension, resulting in elevated left atrium pressure and subsequently left atrial enlargement. Moreover, the activation of renin-angiotensin-aldosterone system (RAAS) activation in patients with hypertension induces left atrial fibrosis and conduction block in the left atrium, resulting in the development of AF. Accordingly, recent studies have shown that effective blockage of RAAS by angiotensin converting enzyme inhibitors or angiotensin receptor antagonist may be effective in both primary and secondary prevention of AF in patients with hypertension, although with controversies. In addition, optimal antithrombotic therapy, blood pressure control as well as rate control for AF are key to the management of patients with AF.

Upstream therapies for management of atrial fibrillation: review of clinical evidence and implications for European Society of Cardiology guidelines. Part II: secondary prevention

Fundamental research into molecular mechanisms of atrial fibrillation (AF) and improved understanding of processes involved in the initiation and maintenance of AF have transformed the traditional approach to its management by targeting only the electrical aspects, usually with antiarrhythmic drugs and, recently, by ablation. The antiarrhythmic potential of upstream therapies, such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers (ARBs), statins, and n-3 (ω-3) polyunsaturated fatty acids, extends beyond the benefit of treating underlying heart disease to modifying the atrial substrate and intervening in specific mechanisms of AF. The key target is structural remodelling of the atria, particularly inflammation and fibrosis, although there is evidence to suggest the direct involvement at the ion channel level. Positive clinical reports supported by robust experimental data have suggested that upstream therapies can be valuable strategies for primary prevention of AF in selected patients and have resulted in several class IIA recommendations in the new European guidelines on AF. However, these results have not been consistently replicated in the secondary prevention setting, and several recent randomized controlled studies failed to demonstrate any effect of upstream therapies on AF burden or on major cardiovascular outcomes. Part II of the review summarizes the evidence base for the use of upstream therapies for secondary prevention of AF.

Regulation of oxidative stress and cardioprotection in diabetes mellitus

Analysis of the Framingham data has shown that the risk of heart failure is increased substantially among diabetic patients, while persons with the metabolic syndrome have an increased risk of both atherosclerosis and diabetes mellitus. Sleep apnea may be related to the metabolic syndrome and systemic inflammation through hypoxia, which might also cause the cardiac remodeling by increased oxidative stress. On the other hand, the renin-angiotensin system is activated in diabetes, and local angiotensin II production may lead to oxidative damage via the angiotensin II type 1 receptor. Basic and clinical data indicate that angiotensin II receptor blockers have the potential to preserve left ventricular function and prevent cardiac remodeling that is exaggerated by oxidative stress in patients with diabetes. Thus, alleviation of oxidative stress might be one possible strategy in the treatment of diabetic patients associated with sleep apnea.

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers decrease the incidence of atrial fibrillation: a meta-analysis

BACKGROUND

There is not a general agreement regarding antiarrhythmic effects on atrial fibrillation (AF) of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs). This study was to assess whether ACEIs and ARBs could decrease the incidence of AF.

MATERIALS AND METHODS

Medline, Embase and Cochrane Library databases were searched for trials reported from 1950 to May 2009. Search terms included 'randomized controlled trial (RCT), controlled clinical trials, random allocation' and medical subject headings that included all spellings of ACEIs and ARBs agents, 'atrial fibrillation' and 'atrial flutter'. Randomized, controlled human trials of ACEIs or ARBs reporting AF were included. Data were extracted independently by two reviewers using a predefined data extraction sheet, including study quality indicators. Meta-analysis and subgroup analyses were carried out with a random effects model.

RESULTS

Twenty-one trials including 91,381 patients and 5730 AF events were identified. Overall, ACEIs/ARBs reduced the relative risk (c) of AF by 25%. In primary and secondary prevention, ACEIs/ARBs decreased the incidence of AF by 24% and 27%, respectively. Patients with hypertension (RR: 0·71, 95%CI: 0·54-0·92), patients with chronic heart failure (RR: 0·58, 95%CI: 0·39-0·87) and those with AF (RR: 0·71, 95%CI: 0·52-0·96) benefited from ACEIs/ARBs treatment.

CONCLUSIONS

ACEIs/ARBs are effective for primary prevention and secondary prevention of AF. They decrease the incidence of AF especially in patients with hypertension, patients with chronic heart failure and those with AF.

Reviewing the future of renin-angiotensin system blockade: the role of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in the prevention of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice, affecting approximately 250,000 Canadians and accounting for more than 120,000 hospitalizations each year. Atrial remodelling, which is at least partially induced by activation of the renin-angiotensin system (RAS), can be reversed by RAS blockade using angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. While RAS antagonists are not considered to be conventional anti-arrhythmic agents, several studies have shown that they may reduce the incidence of AF in patients with heart failure, after myocardial infarction with reduced ejection fraction, and in hypertensive patients. Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers have also been used in association with amiodarone to facilitate sinus rhythm maintenance after electrical cardioversion. Whether RAS blockade prevents recurrent AF in patients at high cardiovascular risk remains unknown.

Update on the association of inflammation and atrial fibrillation

Atrial fibrillation (AF) is a common arrhythmia and is associated with significant morbidity and mortality. The pathogenesis of AF remains incompletely understood and management remains a difficult task. Over the past decade there has been accumulating evidence implicating inflammation in the pathogenesis of AF. Inflammation appears to play a significant role in the initiation and perpetuation of AF as well as the prothrombotic state associated with AF. Inflammatory biomarkers (C-reactive protein and interleukin-6) have been shown to be associated with the future development, recurrence and burden of AF, and the likelihood of successful cardioversion. Therapies directed at attenuating the inflammatory burden appear promising. Animal and clinical studies have evaluated statins, angiotensin-converting enzyme inhibitors/angiotensin-II receptor blockers, and corticosteroids for the treatment or prevention of AF. The purpose of this review is to provide current evidence on the relationship between inflammation and AF and potential therapies available to modulate the inflammatory state in AF.

Focus on renin-angiotensin system modulation and atrial fibrillation control after GISSI AF results

Atrial fibrillation is the most frequently encountered arrhythmia in clinical practice. Given that atrial fibrillation is steadily increasing and that the medium to long-term efficacy of antiarrhythmic drugs has proved poor, it is essential to seek new therapies to prevent its onset and to effectively control recurrences. The study of nonantiarrhythmic drugs that act on the atrial remodeling that constitutes the substrate of the arrhythmia is a new and very interesting field of research. In this regard, several molecules that interact with the renin-angiotensin system at the level of the enzymatic or receptor cascade have been investigated in the past 10 years; some results have been very promising, whereas others have been extremely disappointing. In particular, the publication in 2008 of the results of GISSI AF, a rigorously designed Italian prospective study conducted on a large number of patients, revealed no statistically significant differences between the active drug and a placebo in preventing arrhythmia recurrences. In this study, we reassess the rationale behind the use of this class of drugs for 'antiarrhythmic' purposes, re-examine the most significant results reported in the clinical literature since 1999 and discuss the results of the GISSI AF study in this light.

Inhibition of the renin-angiotensin system for prevention of atrial fibrillation

Atrial fibrillation (AF) is a source of considerable morbidity and mortality. There has been compelling evidence supporting the role of renin-angiotensin system (RAS) in the genesis and perpetuation of AF through atrial remodeling, and experimental studies have validated the utilization of RAS inhibition for AF prevention. This article reviews clinical trials on the use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) for the prevention of AF. Results have been variable, depending on the clinical background of treated patients. ACEIs and ARBs appear beneficial for primary prevention of AF in patients with heart failure, whereas they are not equally effective in hypertensive patients with normal left ventricular function. Furthermore, the use of ACEIs or ARBs for secondary prevention of AF has been found beneficial only after electrical cardioversion. Additional data are needed to establish the potential clinical role of renin-angiotensin inhibition for prevention of AF.

Prevention of recurrent atrial fibrillation with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers: a systematic review and meta-analysis of randomized trials

BACKGROUND

Controversy persists regarding the efficacy of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) in the prevention of recurrent atrial fibrillation (AF). We performed a meta-analysis of randomized controlled trials (RCTs), not designed a priori to test this hypothesis, to explore whether ACEs and ARBs reduce recurrent AF.

METHODS

We performed a systematic literature search for RCTs using ACEIs or ARBs and providing data on the outcome of recurrent AF. Statistical heterogeneity across the trials was tested using the Cochran Q statistic and I(2) was computed to quantify heterogeneity. A 2-sided α error of less than .05 was considered statistically significant (P < .05).

RESULTS

The analysis was based on 8 RCTs including 2323 patients. The Mantel-Haenszel random-effect model was used to calculate relative risk (RR) for studies using ACEIs or ARBs, and for studies using ARBs. The fixed-effect model was used to calculate RR for studies using ACEIs. Meta-analysis of the studies revealed that ACEIs or ARBs significantly reduced the incidence of recurrent AF (RR, 0.611; 95% CI, 0.441-0.847; P = .003). The RR for recurrent AF was 0.643 (95% CI, 0.439-0.941; P = .023) for studies using ARBs and 0.54 (95% CI, 0.377-0.80; P = .002) for studies using ACEIs.

CONCLUSION

In this meta-analysis of RCTs not designed a priori to test the hypothesis, ACEs and ARBs were associated with a significant reduction in recurrent AF. Large-scale randomized trials designed a priori to test the hypothesis are necessary to complete the totality of evidence.

Upstream effect for atrial fibrillation: still a dilemma?

Atrial fibrillation is the most common arrhythmia in clinical practice. Ion channel blocking agents are often characterized by limited long-term efficacy and several side effects. In addition, ablative invasive procedures are neither easily accessible nor always efficacious. The "upstream therapy," which includes angiotensin-converting enzyme inhibitors, aldosterone receptor antagonists, statins, glucocorticoids, and ω-3 poly-unsaturated fatty acids, targets arrhythmia substrate, influencing atrial structural and electrical remodeling that play an essential role in atrial fibrillation induction and maintenance. The mechanisms involved and the most important clinical evidence regarding the upstream therapy influence on atrial fibrillation are presented in this review. Some open questions are also proposed.

Non-antiarrhythmic drugs to prevent atrial fibrillation

Atrial fibrillation (AF) is the most frequent arrhythmia found in clinical practice. The majority of patients with AF are still candidates for antiarrhythmic drug treatment, not only for acute reversion to sinus rhythm but also for long-term treatment to prevent recurrences of AF. Currently available antiarrhythmic drugs, however, are unable to provide complete efficacy in all patients, and present problematic risks of proarrhythmia. The progressively increasing prevalence of AF supports the need to develop improved therapeutic approaches for the clinical management of arrhythmia. Accordingly, new treatment techniques aimed at suppressing the origin of the arrhythmogenic foci have been developed in the last decade. However, ablative treatments are only available for selected patients. Because of these factors, and also because primary prevention of AF should be our goal, the introduction of non-antiarrhythmic agents that could prevent both new-onset AF and recurrences of AF may eventually improve patient outcomes and reduce the incidence of this epidemic disease. The potential clinical value of these non-antiarrhythmic options is currently under active investigation. There is now clinical and experimental evidence that many drugs may have beneficial effects in preventing AF through several possible mechanisms. Non-antiarrhythmic drugs, such as ACE inhibitors and angiotensin receptor blockers, HMG-CoA reductase inhibitors (statins), corticosteroids, and N-3 polyunsaturated fatty acids may have a positive effect in patients with AF or in preventing AF in patients at risk.

Sympathetic neurons express and secrete MMP-2 and MT1-MMP to control nerve sprouting via pro-NGF conversion

Recently, we have shown that high frequency electrical field stimulation (HFES) of sympathetic neurons (SN) induces nerve sprouting by up-regulation of nerve growth factor (NGF) which targets the tyrosine kinase A receptor (TrkA) in an autocrine/paracrine manner. There is increasing evidence that matrix metalloproteinase-2 (MMP-2) is not only involved in extracellular matrix (ECM) turnover but may also exert beneficial effects during neuronal growth. Therefore, this study aimed to investigate the regulation and function of MMP-2 and its major activator membrane type 1-matrix metalloproteinase (MT1-MMP) as well its inhibitor TIMP-1 in SN under conditions of HFES. Moreover, we analyzed molecular mechanisms of the beneficial effect of losartan, an angiotensin II type I receptor (AT-1)blocker on HFES-induced nerve sprouting. Cell cultures of SN from the superior cervical ganglia (SCG) of neonatal rats were electrically stimulated for 48 h with a frequency of 5 or 50 Hz. HFES increased MMP-2 and MT1-MMP mRNA and protein expression, whereas TIMP-1 expression remained unchanged. Under conditions of HFES, we observed a shift from pro- to active-MMP-2 indicating an increase in MMP-2 enzyme activity. Specific pharmacological MMP-2 inhibition contributed to an increase in pro-NGF amount in the cell culture supernatant and significantly reduced HFES-induced neurite outgrowth. Losartan abolished HFES-induced nerve sprouting in a significant manner by preventing HFES-induced NGF, MMP-2, and MT1-MMP up-regulation. In summary, specific MMP-2 blockade prevents sympathetic nerve sprouting (SNS) by inhibition of pro-NGF conversion while losartan abolishes HFES-induced SNS by reducing total NGF, MMP-2 and MT1-MMP expression.

Prevention of atrial fibrillation by Renin-Angiotensin system inhibition a meta-analysis

OBJECTIVES

The authors reviewed published clinical trial data on the effects of renin-angiotensin system (RAS) inhibition for the prevention of atrial fibrillation (AF), aiming to define when RAS inhibition is most effective.

BACKGROUND

Individual studies examining the effects of RAS inhibition on AF prevention have reported controversial results.

METHODS

All published randomized controlled trials reporting the effects of treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers in the primary or secondary prevention of AF were included.

RESULTS

A total of 23 randomized controlled trials with 87,048 patients were analyzed. In primary prevention, 6 trials in hypertension, 2 trials in myocardial infarction, and 3 trials in heart failure were included (some being post-hoc analyses of randomized controlled trials). In secondary prevention, 8 trials after cardioversion and 4 trials assessing the medical prevention of recurrence were included. Overall, RAS inhibition reduced the odds ratio for AF by 33% (p < 0.00001), but there was substantial heterogeneity among trials. In primary prevention, RAS inhibition was effective in patients with heart failure and those with hypertension and left ventricular hypertrophy but not in post-myocardial infarction patients overall. In secondary prevention, RAS inhibition was often administered in addition to antiarrhythmic drugs, including amiodarone, further reducing the odds for AF recurrence after cardioversion by 45% (p = 0.01) and in patients on medical therapy by 63% (p < 0.00001).

CONCLUSIONS

This analysis supports the concept of RAS inhibition as an emerging treatment for the primary and secondary prevention of AF but acknowledges the fact that some of the primary prevention trials were post-hoc analyses. Further areas of uncertainty include potential differences among specific RAS inhibitors and possible interactions or synergistic effects with antiarrhythmic drugs.

Angiotensin II receptor blockers in the prevention of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia. While antiarrhythmic agents and electrical cardioversion are highly effective in restoring sinus rhythm, the results obtained in prevention of recurrences are disappointing. Recently, angiotensin II has been recognized as a key factor in atrial structural and electrical remodeling associated with AF. So there are several potential mechanisms by which inhibition of the renin-angiotensin-aldosterone system may reduce AF. In this review, we report the results of studies evaluating the effect of angiotensin II receptor blockers (ARBs) in various clinical settings (i.e., lone AF, hypertension, high-risk patients, congestive heart failure, secondary prevention). However, many of these studies are small and retrospective and have a limited follow-up; moreover, since AF is related to several causes, chiefly heart diseases, patients with different characteristics have often been enrolled. Thus, it is not surprising that the results obtained are frequently conflicting. With these limitations and considering only the results of larger studies with longer follow-up, ARBs are effective in preventing AF in patients with congestive heart failure or hypertension with left ventricular hypertrophy or coronary artery/cerebrovascular disease. In any case, the use of ARBs is not recommended at present in clinical practice to prevent AF.

Hypertension and atrial fibrillation

Atrial fibrillation (AF) is an emerging public health problem. The most important risk factor for developing chronic AF is uncontrolled hypertension. Uncontrolled hypertension promotes the initiation and perpetuation of AF through atrial remodeling. Experimental evidence has demonstrated the important role of the renin-angiotensin system in atrial remodeling. Retrospective analysis of several large clinical trials and small prospective trials suggests the beneficial role of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in preventing the onset and recurrence of AF in different populations. Several large prospective trials with longer follow-up periods are in progress. These trials may provide definitive evidence for the use of these agents in the prevention of AF.

The effect of pretreatment with renin-angiotensin-aldosterone system blockers on cardioversion success and acute recurrence of atrial fibrillation

BACKGROUND

Renin-angiotensin-aldosterone system (RAS) may be activated during atrial fibrillation (AF). It is unclear whether RAS inhibition may facilitate cardioversion from AF and may prevent acute recurrence of AF (ARAF). We thus investigated the effect of pretreatment with RAS blockers on cardioversion success and ARAF in patients with AF scheduled for elective cardioversion.

METHODS

This observational study included 356 patients with AF undergoing elective pharmacological or electrical cardioversion. Of these patients, 135 were not included based on exclusion criteria and the remaining 221 patients were divided into RAS group (n = 116, 69 male) or non-RAS group (n = 105, 58 male) based on precardioversion use of any RAS blocker.

RESULTS

Hypertension, coronary heart disease and heart failure were more frequent in the RAS group. Cardioversion from AF was more successful in the RAS group than in the non-RAS group (%92 vs. %82, p = 0.026). The rate of ARAF was lower in RAS group compared with that in non-RAS group (17% vs. 31%, p = 0.026). In multivariate analysis, pretreatment with RAS blockers in addition to shock number and enlarged left atrium, independently predicted ARAF (OR: 0.33, 95% CI: 0.15-0.75, p = 0.008). Independent predictors of cardioversion success were shock number and left atrial dilatation, but not use of RAS blocker.

CONCLUSION

Precardioversion use of RAS blockers may reduce ARAF following successful cardioversion of AF, but did not improve electrical cardioversion.

Valsartan for prevention of recurrent atrial fibrillation

BACKGROUND

Atrial fibrillation is the most common cardiac arrhythmia, and no current therapy is ideal for control of this condition. Experimental studies suggest that angiotensin II-receptor blockers (ARBs) can influence atrial remodeling, and some clinical studies suggest that they may prevent atrial fibrillation.

METHODS

We conducted a large, randomized, prospective, placebo-controlled, multicenter trial to test whether the ARB valsartan could reduce the recurrence of atrial fibrillation. We enrolled patients who were in sinus rhythm but had had either two or more documented episodes of atrial fibrillation in the previous 6 months or successful cardioversion for atrial fibrillation in the previous 2 weeks. To be eligible, patients also had to have underlying cardiovascular disease, diabetes, or left atrial enlargement. Patients were randomly assigned to receive valsartan or placebo. The two primary end points were the time to a first recurrence of atrial fibrillation and the proportion of patients who had more than one recurrence of atrial fibrillation over the course of 1 year.

RESULTS

A total of 1442 patients were enrolled in the study. Atrial fibrillation recurred in 371 of the 722 patients (51.4%) in the valsartan group, as compared with 375 of 720 (52.1%) in the placebo group (adjusted hazard ratio, 0.97; 96% confidence interval [CI], 0.83 to 1.14; P=0.73). More than one episode of atrial fibrillation occurred in 194 of 722 patients (26.9%) in the valsartan group and in 201 of 720 (27.9%) in the placebo group (adjusted odds ratio, 0.89; 99% CI, 0.64 to 1.23; P=0.34). The results were similar in all predefined subgroups of patients, including those who were not receiving angiotensin-converting-enzyme inhibitors.

CONCLUSIONS

Treatment with valsartan was not associated with a reduction in the incidence of recurrent atrial fibrillation. (ClinicalTrials.gov number, NCT00376272.)