Pathophysiology and clinical relevance of atrial myopathy

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

Atrial Fibrillation and Aortic Ectasia as Complications of Primary Aldosteronism: Focus on Pathophysiological Aspects

Primary aldosteronism (PA) is the most common cause of secondary hypertension. A growing body of evidence has suggested that, beyond its well-known effects on blood pressure and electrolyte balance, aldosterone excess can exert pro-inflammatory, pro-oxidant and pro-fibrotic effects on the kidney, blood vessels and heart, leading to potentially harmful pathophysiological consequences. In clinical studies, PA has been associated with an increased risk of cardiovascular, cerebrovascular, renal and metabolic complication compared to essential hypertension, including atrial fibrillation (AF) and aortic ectasia. An increased prevalence of AF in patients with PA has been demonstrated in several clinical studies. Aldosterone excess seems to be involved in the pathogenesis of AF by inducing cardiac structural and electrical remodeling that in turn predisposes to arrhythmogenicity. The association between PA and aortic ectasia is less established, but several studies have demonstrated an effect of aldosterone on aortic stiffness, vascular smooth muscle cells and media composition that, in turn, might lead to an increased risk of aortic dilation and dissection. In this review, we focus on the current evidence regarding the potential role of aldosterone excess in the pathogenesis of AF and aortic ectasia.

The effects of ACEI/ARB, aldosterone receptor antagonists and statins on preventing recurrence of atrial fibrillation: A protocol for systematic review and network meta-analysis

BACKGROUND

Atrial fibrillation (AF) is one of the most common arrhythmias, and is high relative to cardiovascular morbidity and mortality. AF-related complications and treatment costs bring about huge health burden, therefore the prevention recurrence of AF is imperative. "Upstream therapy" refers to the use of non-antiarrhythmic drugs (non-AADs) that modify the atrial substrate or target-specific mechanisms of AF to prevent the occurrence or recurrence of the arrhythmia. RAAS Blockers, aldosterone receptor antagonists and statins have an effect on preventing recurrence of atrial fibrillation. This protocol is designed for systematic review and network meta-analysis, which will assess comparative effects and safety of various non-antiarrhythmic drugs in preventing recurrence of atrial fibrillation.

METHODS

The Cochrane Library, MEDLINE, EMBASE, ClinicalTrials.gov will be searched from inception to Aug 31, 2020 to identify relevant studies. The Cochrane "Risk of bias" tool will be used to assess the methodological quality of eligible studies. The pair-wise meta-analysis will be performed by STATA 14.0 software. The network meta-analysis will be implemented in a Bayesian framework using Win BUGS 1.4.3 and the package "gemtc" V.0.8.1 of R-3.6.2 software. The network plots will be drawn using STATA 14.0 software. A comparison-adjusted funnel plot will be used to assess the publication bias using STATA 14.0 software. Quality of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

The results of this network meta-analysis will determine the preventive effect and rank ordering of these interventions for recurrence of AF. The report will follow the PRISMA checklist for network meta-analysis.

CONCLUSION

This network meta-analysis will provide comprehensive evidence-based information in clinical practice.

INPLASY REGISTRATION NUMBER

INPLASY202090004.

Left atrial emptying fraction determined during atrial fibrillation predicts maintenance of sinus rhythm after direct current cardioversion in patients with persistent atrial fibrillation

Echocardiography is the basic imaging technique used to determine the odds of maintaining sinus rhythm (SR) following direct current cardioversion (DCCV) for persistent atrial fibrillation (AF). However, most studies are focused on the echocardiographic parameters obtained during SR resulting from successful DCCV. The aim of this study was to assess the value of the echocardiographic parameters measured before DCCV for the prognosis of SR maintenance after DCCV. The study included 146 patients with persistent AF who underwent DCCV. Clinical and echocardiographic data were collected directly before DCCV and, for patients with SR, one month, six months, and 12 months after DCCV. We found that left atrial emptying fraction (LAEF) assessed during atrial fibrillation was significantly larger in the group with SR maintenance after 12 months than in the group with AF recurrence (30.8±8.3 vs. 24.6±10.4%; p<0.001). In multivariable logistic regression analysis with a model containing echocardiographic parameters, LAEF (OR 1.053; 95% CI 1.011-1.096; p = 0.013) and the E/e'mean ratio (OR 0.883; 95% CI 0.788-0.990; p = 0.033) were independent predictors of SR maintenance. Analyzing a model including clinical and echocardiographic variables, only LAEF (OR 1.046; 95% CI 1-1.095; p = 0.049) and beta-blockers used before DCCV (OR 14.694; 95% CI 1.622-133.139; p = 0.017) were independent predictors of SR maintenance after 12 months. Our results indicate that LAEF measured during AF is a significant predictor of SR maintenance in the 12 months following DCCV due to persistent AF. Our findings confirm the recently raised hypothesis about the superiority of echocardiographic parameters assessing mechanical remodeling over parameters assessing structural remodeling of left atrium in predicting sinus rhythm maintenance after electrical cardioversion.

Atrial Myopathy Underlying Atrial Fibrillation

While AF most often occurs in the setting of atrial disease, current assessment and treatment of patients with AF does not focus on the extent of the atrial myopathy that serves as the substrate for this arrhythmia. Atrial myopathy, in particular atrial fibrosis, may initiate a vicious cycle in which atrial myopathy leads to AF, which in turn leads to a worsening myopathy. Various techniques, including ECG, plasma biomarkers, electroanatomical voltage mapping, echocardiography, and cardiac MRI, can help to identify and quantify aspects of the atrial myopathy. Current therapies, such as catheter ablation, do not directly address the underlying atrial myopathy. There is emerging research showing that by targeting this myopathy we can help decrease the occurrence and burden of AF.

Clinical efficacy of potassium canreonate-canrenone in sinus rhythm restoration among patients with atrial fibrillation - a protocol of a pilot, randomized, double -blind, placebo-controlled study (CANREN-AF trial)

Background

Atrial fibrillation (AF) is the most frequent cardiac arrhythmia which increases the risk of thromboembolic complications and impairs quality of life. An important part of a therapeutic approach for AF is sinus rhythm restoration. Antiarrhythmic agents used in pharmacological cardioversion have limited efficacy and potential risk of proarrhythmia. Simultaneously, underlying conditions of AF should be treated (e.g. electrolyte imbalance, increased blood pressure, neurohormonal disturbances, atrial volume overload). There is still the need for an effective and safe approach to increase AF cardioversion efficacy. This randomized, double-blind, placebo-controlled, superiority clinical study is performed in patients with AF in order to evaluate the clinical efficacy of intravenous canrenone in sinus rhythm restoration.

Methods

Eighty eligible patients with an episode of AF lasting less than 48 h are randomized in a 1:1 ratio to receive canrenone or placebo. Patients randomized to a treatment intervention are receiving canrenone intravenously at a dose of 200 mg within 2–3 min. Subjects assigned to a control group obtain the same volume of 0.9% saline within the same time. The primary endpoint includes return of sinus rhythm documented in the electrocardiogram within 2 h after drug or placebo administration. Other endpoints and safety outcomes analyses, due to expected lack of statistical power, are exploratory.

Discussion

Current evidence supports renin–angiotensin–aldosterone system (RAAS) inhibition as an upstream therapy in AF management. Excess aldosterone secretion results in proarrhythmic effects. Among the RAAS inhibitors, only canrenone is administered intravenously. Canrenone additionally increases the plasma level of potassium, lowers blood pressure and reduces preload. It has been already used in primary and secondary hyperaldosteronism in the course of chronic liver dysfunction and in heart failure.

Trial registration

ClinicalTrials.gov, NCT03536806. Registered on 25 May 2018.

Left atrial mechanical remodelling assessed as the velocity of left atrium appendage wall motion during atrial fibrillation is associated with maintenance of sinus rhythm after electrical cardioversion in patients with persistent atrial fibrillation

The velocity of left atrium appendage (LAA) wall motion during atrial fibrillation (AF) is a potential marker of mechanical remodelling. In this study, we investigated whether the velocity of LAA wall motion during AF predicted the success of electrical cardioversion and long-term sinus rhythm maintenance. Standard echocardiographic data were obtained by transthoracic echocardiography, and LAA wall motion velocities were measured by transoesophageal echocardiography. With logistic regression and receiver operating characteristic curve analyses, we related echocardiographic and clinical data to cardioversion outcomes and sinus rhythm maintenance at 12 months. Of 121 patients prospectively included in the study, electrical cardioversion restored sinus rhythm in 97 (81.2%), and 51 (42%) patients maintained sinus rhythm at 12 months. Patients in whom cardioversion restored sinus rhythm had higher LAA wall motion velocities than did the patients with failed cardioversions (p <0.001). Compared to patients with AF at 12 months, patients who maintained sinus rhythm had lower maximum and end-diastolic left atrial volumes (p ≤ 0.01), lower E/e’ ratios (p = 0.005), higher s’ values (p = 0.013), and higher LAA motion velocities (p < 0.001). On multivariate logistic regression, only LAA wall motion velocity and E/e’ ratios remained significant predictors of sinus rhythm maintenance at 12 months (p ≤ 0.04). LAA wall motion velocity was also a significant predictor of sinus rhythm maintenance when corrected for clinical variables (p = 0.039). Conclusion: LAA wall motion velocity, as a marker of mechanical remodelling, can predict short-term and long-term sinus rhythm maintenance after electrical cardioversion in AF.

Arterial Hypertension, Aldosterone, and Atrial Fibrillation

PURPOSE

Atrial fibrillation is the most common sustained arrhythmia, with a prevalence of 1-2% in the general population and over 15% in people older than 80 years. Due to aging of the population it imposes an increasing burden on the healthcare system because of the need for life-long pharmacological treatment and the associated increased risk of heart failure and hospitalization. Hence, identification of the factors that predispose to atrial fibrillation it is of utmost relevance.

RECENT FINDINGS

Several conditions exist that are characterized by inappropriately high levels of aldosterone, mostly primary aldosteronism and the severe or drug-resistant forms of arterial hypertension. In these forms, aldosterone can cause prominent target organ damage, mostly in the heart, vasculature, and kidney. This review examines the experimental data and clinical evidences that support a link between hyperaldosteronism and atrial fibrillation, and how this knowledge should lead to a change in our management of the hypertensive patients presenting with atrial fibrillation.

The Impact of Repeated Cardioversions for Atrial Fibrillation on Stroke, Hospitalizations, and Catheter Ablation Outcomes

BACKGROUND

Long-term outcomes after direct current cardioversion (DCCV) in patients that receive anticoagulation have demonstrated to have no adverse sequela. Less is known about the impact on atrial fibrillation (AF) outcomes and resource utilization of repeated DCCVs that are often required for long-term rhythm control.

METHODS

A total of 4,135 AF patients >18 years of age that underwent DCCV with long-term system follow-up were evaluated. Patients were stratified by the number of DCCVs received: 1 (n=2,201), 2-4 (n=1,748), and ≥5 (n=186). Multivariable Cox hazard regression was used to determine the association of DCCV categories to the outcomes of death, AF hospitalization, AF ablation, DCCVs, and stroke/transient ischemic attack.

RESULTS

The average follow-up of the patient population was 1,633.1±1,232.9 (median: 1,438.0) days. Patients who underwent 2-4 and ≥5 DCCVs had more comorbidities, namely hypertension, hyperlipidemia and heart failure. Anticoagulation use was common at the time of DCCV in all groups (89.1%, 91.2%, 91.9%, p=0.06) and amiodarone use increased with increasing DCCV category (30.1%, 43.4%, 52.2, p<0.0001). At 5 years, patients that received more DCCVs had higher rates of repeat DCCVs, AF hospitalizations, and ablations. Stroke rates were not increased. Though not statistically significant, 5-year death was increased when comparing DCCV >5 vs. 1, (HR=1.32 [0.89-1.94], p=0.17).

CONCLUSIONS

This study found that the increasing number of DCCVs, despite escalation of other pharmacologic and nonpharmacologic therapies, is a long-term independent risk factor for repeat DCCVs, ablations, and AF hospitalizations among AF patients.

Echocardiographic assessment of left atrial morphology and function to predict maintenance of sinus rhythm after electrical cardioversion in patients with non-valvular persistent atrial fibrillation and normal function or mild dysfunction of left ventricle

BACKGROUND

The aim of this study was to assess whether echocardiographic measurements of left atrial (LA) morphology and function could predict sinus rhythm maintenance after electrical cardioversion among patients with atrial fibrillation (AF) and normal function or mild dysfunction of the left ventricle (LV).

METHODS

One hundred seventeen patients with persistent AF who underwent successful electrical cardioversion were prospectively enrolled. Echocardiography was performed one day subsequent to successful cardioversion. Patients were followed up clinically and electrocardiographically at 1, 6, and 12 months. At 12 months, 61 (52%) patients had maintained sinus rhythm (SR).

RESULTS

Compared to patients who maintained SR, those with AF recurrence had larger LAs, worse LA systolic function, and increased LV filling pressure. On multivariate stepwise logistic regression, E/A ratios (odds ratio [OR] 0.550, 95% confidence interval [CI] 0.341-0.886; p = 0.014) and E/e' ratios (OR 0.871, 95% CI 0.771-0.985; p = 0.027) were significant predictors of AF recurrence. On receiver operator characteristic curve analysis of AF recurrence at 12 months, the area under curve for both E/A and E/e' ratios were 0.726. With an E/A cutoff of 2.2, the sensitivity for predicting AF recur-rence at 12 months was 72%, and specificity was 73%. With an E/e' cutoff of 9.17, the sensitivity for predicting AF recurrence at 12 months was 72%, and specificity was 74%.

CONCLUSIONS

Left ventricular filling pressure assessed with E/A and E/e' ratios predict AF recurrence after electrical cardioversions among patients with AF and normal function of LV.

PR interval prolongation in coronary patients or risk equivalent: excess risk of ischemic stroke and vascular pathophysiological insights

BACKGROUND

Whether PR prolongation independently predicts new-onset ischemic events of myocardial infarction and stroke was unclear. Underlying pathophysiological mechanisms of PR prolongation leading to adverse cardiovascular events were poorly understood. We investigated the role of PR prolongation in pathophysiologically-related adverse cardiovascular events and underlying mechanisms.

METHODS

We prospectively investigated 597 high-risk cardiovascular outpatients (mean age 66 ± 11 yrs.; male 67%; coronary disease 55%, stroke 22%, diabetes 52%) for new-onset ischemic stroke, myocardial infarction (MI), congestive heart failure (CHF), and cardiovascular death. Vascular phenotype was determined by carotid intima-media thickness (IMT).

RESULTS

PR prolongation >200 ms was present in 79 patients (13%) at baseline. PR prolongation >200 ms was associated with significantly higher mean carotid IMT (1.05 ± 0.37 mm vs 0.94 ± 0.28 mm, P = 0.010). After mean study period of 63 ± 11 months, increased PR interval significantly predicted new-onset ischemic stroke (P = 0.006), CHF (P = 0.040), cardiovascular death (P < 0.001), and combined cardiovascular endpoints (P < 0.001) at cut-off >200 ms. Using multivariable Cox regression, PR prolongation >200 ms independently predicted new-onset ischemic stroke (HR 8.6, 95% CI: 1.9-37.8, P = 0.005), cardiovascular death (HR 14.1, 95% CI: 3.8-51.4, P < 0.001) and combined cardiovascular endpoints (HR 2.4, 95% CI: 1.30-4.43, P = 0.005). PR interval predicts new-onset MI at the exploratory cut-off >162 ms (C-statistic 0.70, P = 0.001; HR: 8.0, 95% CI: 1.65-38.85, P = 0.010).

CONCLUSIONS

PR prolongation strongly predicts new-onset ischemic stroke, MI, cardiovascular death, and combined cardiovascular endpoint including CHF in coronary patients or risk equivalent. Adverse vascular function may implicate an intermediate pathophysiological phenotype or mediating mechanism.

Mineralocorticoid receptor antagonists and atrial fibrillation: a meta-analysis

AIMS

Aldosterone has been implicated in atrial remodelling representing a potential target for upstream therapies. Accumulating evidence suggests that mineralocorticoid receptor blockade may have favourable effects on atrial fibrillation (AF) development, although some controversial results have been published. We, therefore, conducted a meta-analysis of randomized clinical trials (RCTs) and observational studies in order to examine the protective role of mineralocorticoid receptor antagonists (MRAs) on AF.

METHODS AND RESULTS

Of the 1337 initially identified records, 3 RCTs and 2 observational studies with 3640 patients were finally analysed. The pooled analysis of the included studies demonstrated that patients treated with MRAs have 31% lower risk of AF compared with controls [relative ratio (RR): 0.69; 95% confidence interval (CI): 0.58-0.83] without any heterogeneity across the studies (I(2) = 0%). This effect was consistent across RCTs (RR: 0.72; 95% CI: 0.55-0.94) and observational studies (RR: 0.67; 95% CI: 0.53-0.84) without heterogeneity. Also, MRAs reduce the risk of AF in both heart failure (HF) (RR: 0.63; 95% CI: 0.50-0.80) and after cardiac surgery (RR: 0.77; 95% CI: 0.61-0.98). Analysing the relative impact of eplerenone and spironolactone, we showed that only eplerenone significantly reduces AF burden (RR: 0.64; 95% CI: 0.44-0.90).

CONCLUSION

Our meta-analysis suggests that MRAs may be effective in AF prevention especially in the HF setting. However, there are insufficient data for the widespread use of aldosterone antagonists solely for AF prevention. Larger RCTs with long-term follow-up in different clinical settings are needed to clarify the impact of MRAs on AF.

Risk factors for atrial fibrillation recurrence: a literature review

Atrial fibrillation is the most common arrhythmia managed in clinical practice and it is associated with an increased risk of mortality, stroke and peripheral embolism. Unfortunately, the incidence of atrial fibrillation recurrence ranges from 40 to 50%, despite the attempts of electrical cardioversion and the administration of antiarrhythmic drugs. In this review, the literature data about predictors of atrial fibrillation recurrence are highlighted, with special regard to clinical, therapeutic, biochemical, ECG and echocardiographic parameters after electrical cardioversion and ablation. Identifying predictors of success in maintaining sinus rhythm after cardioversion or ablation may allow a better selection of patients to undergo these procedures. The aim is to reduce healthcare costs and avoid exposing patients to unnecessary procedures and related complications. Recurrent atrial fibrillation depends on a combination of several parameters and each patient should be individually assessed for such a risk of recurrence.

Impact of aldosterone antagonists on the substrate for atrial fibrillation: aldosterone promotes oxidative stress and atrial structural/electrical remodeling

Atrial fibrillation (AF), the most common cardiac arrhythmia, is an electrocardiographic description of a condition with multiple and complex underlying mechanisms. Oxidative stress is an important driver of structural remodeling that creates a substrate for AF. Oxidant radicals may promote increase of atrial oxidative damage, electrical and structural remodeling, and atrial inflammation. AF and other cardiovascular morbidities activate angiotensin (Ang-II)-dependent and independent cascades. A key component of the renin-angiotensin-aldosterone system (RAAS) is the mineralocorticoid aldosterone. Recent studies provide evidence of myocardial aldosterone synthesis. Aldosterone promotes cardiac oxidative stress, inflammation and structural/electrical remodeling via multiple mechanisms. In HF patients, aldosterone production is enhanced. In patients and in experimental HF and AF models, aldosterone receptor antagonists have favorable influences on cardiac remodeling and oxidative stress. Therapeutic approaches that seek to reduce AF burden by modulating the aldosterone system are likely beneficial but underutilized.

Prolongation of PR interval is associated with endothelial dysfunction and activation of vascular repair in high-risk cardiovascular patients

PURPOSE

Epidemiological studies showed that PR prolongation is associated with increased risk of adverse cardiovascular outcomes. We investigated the relations of PR interval with indices of vascular function and endothelial repair as the underlying mechanisms.

METHODS

The study comprised 348 high-risk patients with prior coronary artery disease, ischemic stroke, and/or diabetes mellitus recruited from medical outpatient clinics and 150 healthy subjects without such a history. PR interval was considered prolonged if >200 ms, as determined from resting 12-lead electrocardiogram. Vascular function was assessed by brachial flow-meditated dilatation (FMD) using high-resolution ultrasound. Circulating CD133(+)/KDR(+) endothelial progenitor cell (EPC) levels were measured by flow cytometry.

RESULTS

Among healthy subjects, PR interval was inversely associated with FMD (R = -0.20, P = 0.015), but not with the level of circulating CD133(+)/KDR(+) EPC (R = 0.05, P = 0.58). Among high-risk cardiovascular patients, PR prolongation >200 ms was more common compared with healthy subjects (45/348 (13 %) versus 4/150 (3 %), P < 0.001). PR interval was associated inversely with FMD (R = -0.14, P = 0.01) and positively with circulating CD133(+)/KDR(+) EPC level (R = +0.14, P = 0.009). Circulating CD133(+)/KDR(+) EPC level was significantly increased in patients with PR prolongation >200 ms (0.87 ± 0.37 versus 0.68 ± 0.42 (log, ×10(-3)/ml), P = 0.005). Adjusted for potential confounders, increased PR interval remained independently associated with increased CD133(+)/KDR(+) EPC by +0.002 (95 % confidence interval (CI) 0.000 to 0.004 (log, ×10(-3)/ml), P = 0.011) and depressed FMD (B = -0.014 %, 95 % CI -0.027 to -0.002, P = 0.026).

CONCLUSIONS

PR prolongation is associated with endothelial dysfunction and evidence of endothelial repair activation in patients with high cardiovascular risk.

Abnormal vascular function in PR-interval prolongation

BACKGROUND

Underlying mechanisms of PR-interval prolongation leading to increased risk of adverse cardiovascular outcomes, including atrial fibrillation, are unclear. This study aims to investigate the relation between PR interval and changes in vascular function.

HYPOTHESIS

We hypothesize that there exists an intermediate pathological stage between electrocardiographic PR prolongation and adverse cardiovascular outcomes, which could be reflected by changes in surrogate measurements of vascular function.

METHODS

We recruited 88 healthy subjects (mean age 57.5 ± 9.8 y, 46% male) from a community-based health screening program who had no history of cardiovascular disease or diabetes mellitus. PR interval was determined from a resting 12-lead electrocardiogram. Vascular function was noninvasively assessed by flow-mediated dilation (FMD) using high-resolution ultrasound and brachial-ankle pulse wave velocity (PWV) using a vascular profiling system.

RESULTS

Only 3 subjects had a PR-interval length longer than the conventional cutoff of 200 ms. The PR-interval length was associated inversely with FMD (Pearson r = -0.30, P = 0.004) and positively with PWV (r = 0.40, P < 0.001). Adjusting for potential confounders, increased PR-interval length by each 25 ms was independently associated with reduced FMD by -1 unit (absolute %, B = -0.04 [95% confidence interval: -0.080 to -0.002, P = 0.040)] and increased PWV by +103 cm/second (B = +4.1 [95% confidence interval: 0.6-7.6, P = 0.023]).

CONCLUSIONS

This study shows that PR-interval length, even in the conventionally normal range, is independently associated with endothelial dysfunction and increased arterial stiffness in healthy subjects free of atherosclerotic disease. This suggests the presence of a systemic, intermediate pathologic stage of the vasculature in PR prolongation before clinically manifest cardiovascular events, and could represent a mediating mechanism.

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.