Rationale and design of the GISSI-Atrial Fibrillation Trial: a randomized, prospective, multicentre study on the use of valsartan, an angiotensin II AT1-receptor blocker, in the prevention of atrial fibrillation recurrence

Total NT-proBNP, a novel biomarker related to recurrent atrial fibrillation

Background

Novel circulating biomarkers may help in understanding the underlying mechanisms of atrial fibrillation (AF), a challenge for AF management and prevention of cardiovascular (CV) events. Whether glycosylation affects the prognostic value of N-terminal pro-B type natriuretic peptide (NT-proBNP) in AF is still unknown.

Objectives

To test how deglycosylated total NT-proBNP, NT-proBNP and a panel of biomarkers are associated with: (1) recurrent AF, (2) first hospitalization for CV reasons.

Methods

A total of 382 patients of the GISSI-AF trial in sinus rhythm with a history of AF, echocardiographic variables, total NT-proBNP, NT-proBNP and nine additional biomarkers [Total N-terminal pro-B type natriuretic peptide (Total NT proBNP), N-terminal pro-B type natriuretic peptide (NTproBNP), Angiopoietin 2 (Ang2), Bone morphogenic protein-10 (BMP10), Dickkopf-related protein-3 (DKK3), Endothelial cell specific molecule-1 (ESM1), Fatty acid-binding protein 3 (FABP3), Fibroblast growth factor 23 (FGF23), Growth differentiation factor-15 (GDF15), Insulin-like growth factor-binding protein-7 (IGFBP7) and Myosin binding protein C3 (MYPBC3)]. were assayed at baseline, 6 and 12 months under blind conditions in a laboratory at Roche Diagnostics, Penzberg, Germany. The associations between circulating biomarkers and AF at the 6- and 12-month visits, and their predictive value, were assessed in multivariable models with logistic regression analysis and Cox proportional hazards regression analysis. Biomarkers associations were modelled for 1SD increase in their level.

Results

Over a median follow-up of 365 days, 203/382 patients (53.1%) had at least one recurrence of AF and 16.3% were hospitalized for CV reasons. Total NT-proBNP, NT-proBNP, Ang2 and BMP10 showed the strongest associations with ongoing AF. Natriuretic peptides also predicted recurrent AF (total NT-proBNP: HR:1.19[1.04–1.36], p = 0.026; NT-proBNP: HR:1.19[1.06–1.35], p = 0.016; Ang2: HR:1.07[0.95–1.20], p = 0.283; BMP10: HR:1.09[0.96–1.25], p = 0.249) and CV hospitalization (total NT-proBNP: HR:1.57[1.29–1.90], p < 0.001 1.63], p = 0.097).

Conclusions

The association of total NT-proBNP with the risk of AF first recurrence was similar to that of NT-proBNP, suggesting no influence of glycosylation. Analogous results were obtained for the risk of first hospitalization for CV reasons. Natriuretic peptides, Ang2 and BMP10 were associated with ongoing AF. Findings from the last two biomarkers point to a pathogenic role of cardiac extracellular matrix and cardiomyocyte growth in the myocardium of the right atrium and ventricle.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02358-y.

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

PURPOSE

Atrial fibrillation (AF) is the most common arrhythmia and has an increasing impact on public health because of its morbidity and mortality. Clinical and diagnostic tests to predict the recurrence of arrhythmia and clinical events before AF becomes permanent are still an open issue.

METHODS

307 out of 1442 patients in sinus rhythm, at high risk of recurrence of AF enrolled in the GISSI-AF study, participated in a substudy with echocardiographic and biohumoral evaluation at baseline and at 12-month follow-up. The relations between biomarker concentrations and echocardiographic parameters with study endpoints in 1 year, were analysed by a stepwise multivariable Cox model (entry criteria p < 0.5 and stay criteria p < 0.2).

RESULTS

The echocardiographic variables, cardiac markers and clinical variables considered in the statistical model indicated a higher concentration of NT-proBNP at baseline as the strongest factor related to time of first AF recurrence (HR 1.42; 95 %CI 1.23-1.46), first CV hospitalization (HR 1.58; 95 %CI 1.31-1.92) and increasing duration of recurrent AF (OR 2.16; 95 %CI 1.52-3.08). Valsartan treatment was not related to clinical events.

CONCLUSIONS

In patients in sinus rhythm with a history of AF a higher concentration of NT-proBNP at baseline was the strongest independent risk factor for first AF recurrence and its duration, and for the first hospital admission for cardiovascular reasons.

Prerequisites for Exploring Predictors of Chronic Atrial Fibrillation Recurrence After Ablation

The ablation treatment for the atrial fibrillation extends to the persistent atrial fibrillation now. However, the cure rate of persistent atrial fibrillation by Radiofrequency Ablation is lower than paroxysmal atrial fibrillation and we really want to know is the information that what kind of persistent atrial fibrillation ablation therapy is effective for. Therefore, it is wished the predictors of recurrence after the ablation for the persistent atrial fibrillation is confirmed, but does not yet confirm. The cause that is not confirmed seems to be present in many factors including the gene which the atrial fibrillation occurs in and persist, the change of pathology into remodeling according to progression of atrial fibrillation and strategy of the ablation corresponding to them. Left atrium diameter, Duration of atrial fibrillation and Cardiac Function that are involved deeply in atrial muscle and electric remodeling, and Ablation strategy corresponding to them are considered based on the conventional report. It can be stated now, however, that persistent atrial fibrillation patients with some degree (although this "some degree" has not been clearly defined) of enlarged left atrium diameter, prolonged atrial fibrillation duration, or decreased cardiac function may also revert to sinus rhythm with Radiofrequency Ablation, more efficient treatment may be developed in the future and reversion to sinus rhythm may increase the benefit to patients. In summary, RF ablation for persistent AF is currently required with further study of the predictors of recurrence after the ablation for the persistent atrial fibrillation.

Clinical characteristics of patients with asymptomatic recurrences of atrial fibrillation in the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico-Atrial Fibrillation (GISSI-AF) trial

BACKGROUND

Atrial fibrillation (AF) is a common arrhythmia that frequently recurs after restoration of sinus rhythm. In a consistent percentage of cases, AF recurrences are asymptomatic, thus making its clinical management difficult in relation to both therapeutic efficacy and thromboembolic risk.

METHODS

The GISSI-AF trial enrolled 1,442 patients in sinus rhythm with previous AF episodes. Patients were randomized to valsartan or placebo and followed for 12 months. To improve the likelihood of detecting arrhythmic recurrences, arrhythmic follow-up was based on both programmed or symptom-related control visits and transtelephonic electrocardiographic transmissions. The present post hoc analysis was performed on 1,638 arrhythmic episodes that occurred in 623 patients.

RESULTS

Asymptomatic AF recurrences were present in 49.5% of patients. In multivariable analysis, asymptomatic AF recurrences were significantly associated with a longer duration of qualifying arrhythmias (odds ratio [95% CI] 1.57 (1.26-1.97), P < .0001). A lower ventricular response (P < .001) and a longer duration of the arrhythmic recurrence (P < .001) characterized asymptomatic episodes. Patients with asymptomatic events were more likely to be in AF at the time of electrocardiographic control at the end of the 12-month follow-up (adjusted odds ratio [95% CI] 4.9 (2.8-8.4), P < .001). Moreover, a higher CHADS(2) (Congestive heart failure, history of Hypertension, Age≥75 years, Diabetes mellitus, and past history of Stroke or TIA doubled) score and a more frequent use of amiodarone, calcium-channel blockers, and digitalis characterized patients with asymptomatic, whereas 1C drugs were more often used in subjects with symptomatic recurrences.

CONCLUSION

Asymptomatic AF recurrences were frequent in the GISSI-AF study population in patients who were more likely to develop persistent-permanent AF and were characterized by an increased thromboembolic risk.

Inefficacy interim monitoring procedures in randomized clinical trials: the need to report

If definitive evidence concerning treatment effectiveness becomes available from an ongoing randomized clinical trial, then the trial could be stopped early, with the public release of results benefiting current and future patients. However, stopping an ongoing trial based on accruing outcome data requires methodological rigor to preserve validity of the trial conclusions. This has led to the use of formal interim monitoring procedures, which include inefficacy monitoring that will stop a trial early when the experimental treatment appears not to be working. For participants, inefficacy monitoring is especially important as it ensures that they are not being treated worse than if they had not enrolled on the trial. We discuss the importance of reporting with trial results the formal interim inefficacy monitoring guidelines that were utilized, and, if none were used, the reasons for their absence. A survey of two leading medical journals suggests that this is not current practice.

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.

Circulating cardiovascular biomarkers in recurrent atrial fibrillation: data from the GISSI-atrial fibrillation trial

OBJECTIVE

we evaluated the prognostic role of circulating cardiovascular biomarkers in patients with a history of recent atrial fibrillation (AF).

BACKGROUND

predicting long-term maintenance of sinus rhythm in patients with AF is difficult.

METHODS

plasma concentrations of three specific cardiac markers [high-sensitivity troponin T (hsTnT), N-terminal probrain natriuretic peptide (NT-proBNP) and mid-regional proatrial natriuretic peptide (MR-proANP)] and three stable fragments of vasoactive peptides [mid-regional proadrenomedullin (MR-proADM), copeptin (CT-proAVP) and CT-proendothelin-1 (CT-proET-1)] were measured at baseline and after 6 and 12 months in 382 patients enrolled in the GISSI-AF study, a prospective randomized trial to determine the effect of valsartan to reduce the recurrence of AF. The association between these markers, clinical characteristics and recurrence of AF was tested by univariate and multivariate Cox models.

RESULTS

mean patient age was 68 ± 9 years (37.2% females). A total of 84.8% of patients had a history of hypertension. In total, 59.7% qualified for history of AF because of successful cardioversion, 11.8% because of two or more episodes of AF in the 6 months preceding randomization and 28.5% because of both. Patients in AF at 6 or 12 months (203 (53.1%) with first recurrence) had significantly higher concentrations of most biomarkers. Despite low baseline levels, higher concentrations of hsTnT {adjusted hazard ratio (HR) [95% confidence intervals (CIs) for 1 SD increment] (1.15 [1.04-1.28], P = 0.007), MR-proANP (1.15 [1.01-1.30], P = 0.04), NT-proBNP (1.24 [1.11-1.39], P = 0.0001) and CT-proET-1 (1.16 [1.01-1.33], P = 0.03) independently predicted higher risk of a first recurrence of AF. Changes over time of MR-proANP tended to predict subsequent recurrence (adjusted HR [95%CI]) (1.53 [0.98-2.37], P = 0.06).

CONCLUSION

circulating markers of cardiomyocyte injury/strain and endothelin are related to recurrence of AF in patients in sinus rhythm with a history of recent AF.

Clinical predictors of atrial fibrillation recurrence in the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico-Atrial Fibrillation (GISSI-AF) trial

BACKGROUND

Atrial fibrillation (AF) is a common arrhythmia that frequently recurs after restoration of sinus rhythm (SR). Identifying risk factors for recurrence may help define the best strategy for secondary prevention.

METHODS

The GISSI-AF trial enrolled 1,442 patients in SR with at least 2 documented AF episodes in the previous 6 months or after cardioversion in the last 2 weeks. Patients were randomized to valsartan or placebo; all other treatments for AF or underlying heart diseases were allowed. Primary end points were time to first recurrence of AF and proportion of patients with >1 AF episode during 1-year follow-up. We evaluated clinical and electrocardiographic baseline characteristics of all patients to identify independent predictors for AF recurrence using a Cox multivariable model.

RESULTS

Risk factors for AF recurrence were a history of 2 or more AF episodes in the previous 6 months, independent of the modality of SR restoration, spontaneous (HR 1.42, 95% CI 1.14-1.77, P = .002), or by cardioversion (HR 1.19, 95% CI 1.01-1.40, P = .038), and a lower heart rate during SR (HR 0.99, 95% CI 0.99-1.00, P = .052). The risk factors were the same for >1 AF recurrence. Patients treated with amiodarone had a lower risk for both end points (P < .0001 and P = .017), whereas those on diuretics had a greater risk (P = .009 and P = .003).

CONCLUSIONS

In the GISSI-AF study population, AF history had significant prognostic value independent of the modality of SR restoration. Amiodarone and diuretic treatment affected the rate of AF recurrence.

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.

Novel approaches for pharmacological management of atrial fibrillation

In the light of the progressively increasing prevalence of atrial fibrillation (AF), medical awareness of the need to develop improved therapeutic approaches for the arrhythmia has also risen over the last decade. AF reduces quality of life and is associated with increased morbidity and mortality. Despite several setbacks as a result of negative results from rhythm control trials, the potential advantages of sinus-rhythm (SR) maintenance have motivated continued efforts to design novel pharmacological options aiming to terminate AF and prevent its recurrence, with a hope that optimized medical therapy will improve outcomes in AF patients. Pathophysiologically, AF is associated with electrical and structural changes in the atria, which increase the propensity to arrhythmia perpetuation but may eventually allow for new modalities for therapeutic intervention. Antiarrhythmic drug therapy has traditionally targeted ionic currents that modulate excitability and/or repolarization of cardiac myocytes. Despite efficacious suppression of ventricular and supraventricular arrhythmias, traditional antiarrhythmic drugs present problematic risks of pro-arrhythmia, potentially leading to excess mortality in the case of Na+-channel blockers or IKr (IKr=the rapid component of the delayed rectifier potassium current) blockers. New anti-AF agents in development do not fit well into the classical Singh and Vaughan-Williams formulation, and are broadly divided into 'atrial-selective compounds' and 'multiple-channel blockers'. The prototypic multiple-channel blocker amiodarone is the most efficient presently available compound for SR maintenance, but the drug has extra-cardiac adverse effects and complex pharmacokinetics that limit widespread application. The other available drugs are not nearly as efficient for SR maintenance and have a greater risk of proarrhythmia than amiodarone. Two new antiarrhythmic drugs are on the cusp of introduction into clinical practice. Vernakalant affects several atrially expressed ion channels and has rapid unbinding Na+-channel blocking action along with promising efficacy for AF conversion to SR. Dronedarone is an amiodarone derivative with an electrophysiological profile similar to its predecessor but lacking most amiodarone-associated adverse effects. Furthermore, dronedarone has shown benefits for important clinical endpoints, including cardiovascular mortality in specific AF populations, the first AF-suppressing drug to do so in prospective randomized clinical trials. Agents that modulate non-ionic current targets (termed 'upstream' therapies) may help to modify the substrate for AF maintenance. Among these, drugs such as angiotensin II type 1 (AT1) receptor antagonists, immunosuppressive agents or HMG-CoA reductase inhibitors (statins) deserve mention. Finally, drugs that block atrial-selective ion-channel targets such as the ultra-rapid delayed rectifier current (IKur) and the acetylcholine-regulated K+-current (IKACh) are presently in development. The introduction of novel antiarrhythmic agents for the management of AF may eventually improve patient outcomes. The potential value of a variety of other novel therapeutic options is currently under active investigation.

The 2009 Canadian Hypertension Education Program recommendations for the management of hypertension: Part 2--therapy

OBJECTIVE

To update the evidence-based recommendations for the prevention and management of hypertension in adults for 2009.

OPTIONS AND OUTCOMES

For lifestyle and pharmacological interventions, evidence from randomized controlled trials and systematic reviews of trials was preferentially reviewed. Changes in cardiovascular morbidity and mortality were the primary outcomes of interest. However, for lifestyle interventions, blood pressure lowering was accepted as a primary outcome given the lack of long-term morbidity and mortality data in this field. Progression of kidney dysfunction was also accepted as a clinically relevant primary outcome among patients with chronic kidney disease.

EVIDENCE

A Cochrane collaboration librarian conducted an independent MEDLINE search from 2007 to August 2008 to update the 2008 recommendations. To identify additional published studies, reference lists were reviewed and experts were contacted. All relevant articles were reviewed and appraised independently by both content and methodological experts using prespecified levels of evidence.

RECOMMENDATIONS

For lifestyle modifications to prevent and treat hypertension, restrict dietary sodium to less than 2300 mg (100 mmol)/day (and 1500 mg to 2300 mg [65 mmol to 100 mmol]/day in hypertensive patients); perform 30 min to 60 min of aerobic exercise four to seven days per week; maintain a healthy body weight (body mass index 18.5 kg/m(2) to 24.9 kg/m(2)) and waist circumference (smaller than 102 cm for men and smaller than 88 cm for women); limit alcohol consumption to no more than 14 units per week in men or nine units per week in women; follow a diet that is reduced in saturated fat and cholesterol, and that emphasizes fruits, vegetables and low-fat dairy products, dietary and soluble fibre, whole grains and protein from plant sources; and consider stress management in selected individuals with hypertension. For the pharmacological management of hypertension, treatment thresholds and targets should be predicated on by the patient's global atherosclerotic risk, target organ damage and comorbid conditions. Blood pressure should be decreased to lower than 140/90 mmHg in all patients, and to lower than 130/80 mmHg in those with diabetes mellitus or chronic kidney disease. Most patients will require more than one agent to achieve these target blood pressures. Antihypertensive therapy should be considered in all adult patients regardless of age (caution should be exercised in elderly patients who are frail). For adults without compelling indications for other agents, initial therapy should include thiazide diuretics. Other agents appropriate for first-line therapy for diastolic and/or systolic hypertension include angiotensin- converting enzyme (ACE) inhibitors (in patients who are not black), long-acting calcium channel blockers (CCBs), angiotensin receptor antagonists (ARBs) or beta-blockers (in those younger than 60 years of age). A combination of two first-line agents may also be considered as the initial treatment of hypertension if the systolic blood pressure is 20 mmHg above the target or if the diastolic blood pressure is 10 mmHg above the target. The combination of ACE inhibitors and ARBs should not be used. Other agents appropriate for first-line therapy for isolated systolic hypertension include long- acting dihydropyridine CCBs or ARBs. In patients with angina, recent myocardial infarction or heart failure, beta-blockers and ACE inhibitors are recommended as first-line therapy; in patients with cerebrovascular disease, an ACE inhibitor/diuretic combination is preferred; in patients with proteinuric nondiabetic chronic kidney disease, ACE inhibitors or ARBs (if intolerant to ACE inhibitors) are recommended; and in patients with diabetes mellitus, ACE inhibitors or ARBs (or, in patients without albuminuria, thiazides or dihydropyridine CCBs) are appropriate first-line therapies. All hypertensive patients with dyslipidemia should be treated using the thresholds, targets and agents outlined in the Canadian Cardiovascular Society position statement (recommendations for the diagnosis and treatment of dyslipidemia and prevention of cardiovascular disease). Selected high-risk patients with hypertension who do not achieve thresholds for statin therapy according to the position paper should nonetheless receive statin therapy. Once blood pressure is controlled, acetylsalicylic acid therapy should be considered.

VALIDATION

All recommendations were graded according to strength of the evidence and voted on by the 57 members of the Canadian Hypertension Education Program Evidence-Based Recommendations Task Force. All recommendations reported here achieved at least 95% consensus. These guidelines will continue to be updated annually.

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.)

The effect of angiotensin receptor blockers on C-reactive protein and other circulating inflammatory indices in man

Anti-inflammatory properties may contribute to the pharmacological effects of angiotensin II receptor blockers (ARBs), a leading therapeutic class in the management of hypertension and related cardiovascular and renal diseases. That possibility, supported by consistent evidence from in-vitro and animal studies showing pro-inflammatory properties of angiotensin II, has been evaluated clinically by measuring the effect of ARBs on C-reactive protein and other circulating indices of inflammation (e-selectin, adhesion molecules, interleukin-6, tissue necrosis factor-alpha, monocyte chemoattractant protein-1) of potential clinical relevance, a body of evidence that this paper aims to review.

Prevention of atrial fibrillation: report from a national heart, lung, and blood institute workshop

The National Heart, Lung, and Blood Institute convened an expert panel April 28 to 29, 2008, to identify gaps and recommend research strategies to prevent atrial fibrillation (AF). The panel reviewed the existing basic scientific, epidemiological, and clinical literature about AF and identified opportunities to advance AF prevention research. After discussion, the panel proposed the following recommendations: (1) enhance understanding of the epidemiology of AF in the population by systematically and longitudinally investigating symptomatic and asymptomatic AF in cohort studies; (2) improve detection of AF by evaluating the ability of existing and emerging methods and technologies to detect AF; (3) improve noninvasive modalities for identifying key components of cardiovascular remodeling that promote AF, including genetic, fibrotic, autonomic, structural, and electrical remodeling markers; (4) develop additional animal models reflective of the pathophysiology of human AF; (5) conduct secondary analyses of already-completed clinical trials to enhance knowledge of potentially effective methods to prevent AF and routinely include AF as an outcome in ongoing and future cardiovascular studies; and (6) conduct clinical studies focused on secondary prevention of AF recurrence, which would inform future primary prevention investigations.

Omega-3 fatty acid supplementation reduces one-year risk of atrial fibrillation in patients hospitalized with myocardial infarction

PURPOSE

Current strategies for avoiding atrial fibrillation (AF) are of limited value. We aim to assess the relationship between omega-3 fatty acids (n-3 PUFA) and AF occurrence in post-myocardial infarction (MI) patients.

METHODS

A population study, linking hospital discharge records, prescription databases, and vital statistics, was conducted and included all consecutive patients with MI (ICD-9: 410) in six Italian local health authorities over a 3-year period. A propensity score (PS)-based, 5-to-1, greedy 1:1 matching algorithm was used to check consistency of results. Sensitivity analysis was performed to assess the robustness of findings.

RESULTS

N-3 PUFA reduced the relative risk of the hospitalization for AF [hazard ratio (HR) 0.19, 95% CI 0.07-0.51] and was associated with a further and complementary reduction in all-cause mortality (HR 0.15, 95% CI 0.05-0.46). PS-based matched analysis and sensitivity analysis confirmed the main results.

CONCLUSION

n-3 PUFA reduced both all-cause mortality and incidence of 1-year AF in patients hospitalized with MI.

The role of the renin-angiotensin system in atrial fibrillation and the therapeutic effects of ACE-Is and ARBS

Atrial fibrillation (AF) is the most common rhythm disturbance in medical practice and represents a very expensive health problem. AF can be managed with the prevention of thromboembolism and either a rate control of rhythm strategy. As both strategies have important limitations, probably a preventative strategy in patients at risk of developing arrhythmia can be a more attractive option. The renin-angiotensin system (RAS) seems to be involved in the genesis of arrhythmia by the following two mechanisms: 1. the induction of atrial fibrosis and structural remodelling by mitogen-activated protein kinase (MAPK) expression and reduction of collagenase activity; 2. the induction of electrical remodelling by shortening of the atrial effective refractory period (AERP) and of the action potential duration. For these reasons it has been hypothesized that angiotensin-converting enzyme inhibitors (ACE-Is) and angiotensin-II receptor blockers (ARBs) may play a role in preventing AF recurrence. The aim of the present review was to analyse evidence supporting the usefulness of RAS inhibition in patients with AF in order to focus on which specific subset of patients it would most favour. After reviewing the literature, we conclude that, although many studies and meta-analysis have supported the advantage of RAS block in preventing AF recurrence, it is premature to recommend the use of ACE-Is and ARBs specifically for the prevention of AF. However we believe that as these drugs are safe and manageable, they should be considered the drugs of choice in patients with AF and coexisting clinical conditions such as hypertension, coronary disease, heart failure and diabetes mellitus.

Non-antiarrhythmic medications for atrial fibrillation: from bench to clinical practice

Many treatment modalities have been developed over the years for the management of atrial fibrillation (AF). While they are still considered the first line of treatment for suppression of AF, antiarrhythmics often lead to treatment failure, complications and undesired consequences. Pulmonary vein ablation is an invasive procedure which is not always curative. Recently, there have been a variety of studies reporting the potential antiarrhythmic effects of various nonantiarrhythmic agents. This paper aims to provide a comprehensive review of the findings reported thus far about the antiarrhythmic effects of agents which are not antiarrhythmic drugs themselves, but which have been found to offer promise in the prevention and treatment of AF.

Drug therapy for atrial fibrillation

Atrial fibrillation (AF) is the most frequently diagnosed arrhythmia. Prevalence increases with age, and the overall incidence is expected to increase as the population continues to age. Choice of pharmacologic therapy for atrial fibrillation depends on whether or not the goal of treatment is maintaining sinus rhythm or tolerating atrial fibrillation with adequate control of ventricular rates. New antiarrhythmic drugs are being tested in clinical trials. Drugs that target remodeling and inflammation are being tested for their use as prevention of AF or as adjunctive therapy.

Angiotensin II receptor blockers and cardiovascular protection: focus on left ventricular hypertrophy regression and atrial fibrillation prevention

Left ventricular hypertrophy (LVH) and atrial fibrillation (AF) are strong predictors of cardiovascular (CV) morbidity and mortality, independently of blood pressure levels and other modifiable and nonmodifiable risk factors. The actions of circulating and tissue angiotensin II, mediated by AT1 receptors, play an important role in the development of a wide spectrum of cardiovascular alterations, including LVH, atrial enlargement and AF. Growing experimental and clinical evidence suggests that antihypertensive drugs may exert different effects on LVH regression and new onset AF in the setting of arterial hypertension. Since a number of large and adequately designed studies have found angiotensin II receptor blockers (ARBs) to be more effective in reducing LVH than beta-blockers and data are also available showing their effectiveness in preventing new or recurrent AF, it is reasonable to consider this class of drugs among first line therapies in patients with hypertension and LVH (a very high risk phenotype predisposing to AF) and as adjunctive therapy to antiarrhythmic agents in patients undergoing pharmacological or electrical cardioversion of AF.

Prevention of new-onset atrial fibrillation and its predictors with angiotensin II-receptor blockers in the treatment of hypertension and heart failure

Atrial fibrillation is the most frequent occurring sustained cardiac arrhythmia and it is related to common cardiac disease conditions. Hypertension increases the risk of atrial fibrillation by approximately two-fold and, because of the high prevalence of hypertension, it accounts for more cases of atrial fibrillation than any other risk factor. In recent years, there are two large hypertension trials (LIFE and VALUE) and two large heart failure trials (CHARM and Val-HeFT) reporting the beneficial effect of angiotensin II-receptor blockers (ARBs) on new-onset atrial fibrillation, beyond the blood pressure-lowering effect. Blockade of the renin-angiotensin system may prevent left atrial dilatation, atrial fibrosis, dysfunction and conduction velocity slowing. Some studies also indicate direct anti-arrhythmic properties. This review aims to consider the preventive effect of ARBs on new-onset atrial fibrillation observed in recent reports from these trials, and to discuss possible mechanisms of the beneficial effect of angiotensin II-receptor blockade.

Future directions in antiarrhythmic drug therapy for atrial fibrillation

Atrial fibrillation is the most commonly sustained cardiac arrhythmia. Drugs currently approved by the US FDA for the treatment of this arrhythmia are imperfect owing to either side effects or limited efficacy. Drug development strategies have focused on two areas: the modification of existing agents – such as Class III drugs aimed at improving their safety and efficacy profile – and targeting newly postulated mechanisms of atrial fibrillation. In this article, we review new drugs currently in development and promising drug strategies for atrial fibrillation prevention and treatment.

Efficacy of Angiotensin Receptor Blockers in Cardiovascular Disease

The cardiovascular continuum describes the progression of pathophysiologic events from cardiovascular risk factors to symptomatic cardiovascular disease (CVD) and life-threatening events. Pharmacologic intervention early in the continuum may prevent or slow CVD development and improve quality of life. The renin-angiotensin-aldosterone system (RAAS) is central to the pathophysiology of CVD at many stages of the continuum. Numerous clinical trials of angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) have shown that RAAS blockade provides benefits to patients across the continuum. ARBs are as effective as ACE inhibitors in the treatment of hypertension; however tolerability and adherence to therapy appear to be improved with ARBs. Large clinical trials have shown that ARBs may provide therapeutic benefits beyond blood pressure control in patients with diabetes, heart failure or at risk of heart failure following a myocardial infarction. In addition, ARBs have been shown to provide protective effects in patients with impaired renal function or left ventricular hypertrophy. Additional clinical trials are ongoing to further characterize the role of ARBs in CVD management.

Clinical trials, the renin angiotensin system and atrial fibrillation

PURPOSE OF REVIEW

Atrial fibrillation is the most common clinical arrhythmia. Current treatment strategies are far from optimal. One new research direction is to target the atrial fibrillation substrate and to examine whether drugs can produce atrial structural and/or electrophysiological remodeling and whether this results in a reduction in atrial fibrillation burden.

RECENT FINDINGS

Two prospective randomized studies have shown that the addition of an angiotensin converting enzyme inhibitor or an angiotensin receptor blocker to amiodarone reduces the recurrence rate of atrial fibrillation after electrical cardioversion. There are ten completed prospective clinical trials with atrial fibrillation as a secondary endpoint or assessed in post-hoc analysis. Five of these studies have reported a positive impact of angiotensin converting enzyme inhibitors or angiotensin receptor blockers on atrial fibrillation burden. A meta-analysis showed that active drugs reduced the overall risk of development of atrial fibrillation by 28%. Patients in the heart failure trials obtained most benefit from these drugs (relative risk reduction 44%, P = 0.07).

SUMMARY

The initial basic science and clinical trial data suggest that modulation of the renin angiotensin system may be an effective treatment for atrial fibrillation. The following, however, remain to be clarified: do these drugs have a clinically meaningful impact on atrial fibrillation burden; if there is an impact, is it similar in all atrial fibrillation patients or just in certain subsets; do angiotensin converting enzyme inhibitors and angiotensin receptor blockers have similar benefits; and is there a role for aldosterone antagonists?

Do angiotensin II receptor blockers increase the risk of myocardial infarction?

AIMS

The uncertainty surrounding safety of angiotensin receptor blockers (ARBs) increased after publication of experimental and clinical studies which suggested an excess risk of myocardial infarction (MI) in people treated with ARBs.

METHODS AND RESULTS

We performed a meta-analysis of randomised clinical trials, which compared ARBs with either a placebo or active drugs different from ARBs. Overall, ARBs were not associated with an excess risk of MI [odds ratio (OR): 1.03 in a random-effect model and 1.02 in a fixed-effect model]. In pre-specified subgroup analyses, incidence of MI did not differ between ARBs and either placebo (OR: 0.96; 95% CI: 0.84-1.10) or angiotensin-converting enzyme (ACE)-Inhibitors (OR: 0.99; 95% CI: 0.91-1.07). Incidence of MI was slightly higher with ARBs than with drug classes different from ACE-Inhibitors (OR: 1.16; P=0.06 in a random-effect model and 0.017 in a fixed-effect model). Cardiovascular mortality did not differ between ARBs and drugs different from ARBs (OR: 1.00 in a random-effect model and 0.99 in a fixed-effect model) and it was slightly lesser with ARBs than with placebo (OR: 0.91; 95% CI: 0.83-0.99; P=0.042) in a pre-specified subgroup analysis.

CONCLUSION

Our findings do not support the hypothesis that ARBs increase the risk of MI.