Pulmonary vein isolation with concomitant renal artery denervation is associated with reduction in both arterial blood pressure and atrial fibrillation burden: Data from implantable cardiac monitor

Hypertension and Atrial Fibrillation: Bridging the Gap Between Mechanisms, Risk, and Therapy

Background and objectives: Atrial fibrillation (AF), the most prevalent sustained arrhythmia, poses a significant public health challenge due to its links with stroke, heart failure, and mortality. Hypertension, a primary modifiable cardiovascular risk factor, is a well-established risk factor for AF that facilitates structural and electrical changes in the atria, including dilation, fibrosis, and pressure overload. Material and Methods: we conducted a literature search regarding the shared mechanisms, risks and treatments of hypertension and atrial fibrillation. Results: The renin-angiotensin-aldosterone system plays a pivotal role in this remodelling and inflammation, increasing AF susceptibility. Uncontrolled hypertension complicates AF management, diminishing the effectiveness of mainstay treatments, including antiarrhythmic drugs, catheter ablation, and cardioversion. Effective blood pressure management, particularly with therapies targeting the renin-angiotensin-aldosterone system (RAAS), can lower the risk of new-onset AF and reduce the incidence of recurrent AF, enhancing the success of rhythm control strategies. These antihypertensive therapies mitigate myocardial hypertrophy and fibrosis and attenuate both atrial pressure strain and the inflammatory response, mitigating the substrates for AF. Conclusion: This review highlights the urgent need for integrated strategies that combine BP control, AF screening, and lifestyle modifications to minimise the burden of AF and its complications. Future research should investigate the specific mechanisms of cellular-level interactions associated with a hypertensive predisposition to AF, including systematic inflammation and the role of genetics, the impact of blood pressure variations on AF risk, and individualised treatment strategies specifically targeting the shared mechanisms, simultaneously propagating hypertension and AF.

Long-Term Changes in Atrial Arrhythmia Burden After Renal Denervation Combined With Pulmonary Vein Isolation: SYMPLICITY-AF

BACKGROUND

The autonomic nervous system plays an important role in atrial fibrillation (AF) and hypertension. Renal denervation (RDN) lowers blood pressure (BP), but its role in AF is poorly understood.

OBJECTIVES

The purpose of this study was to investigate whether RDN reduces AF recurrence after pulmonary vein isolation (PVI).

METHODS

This study randomized patients from 8 centers (United States, Germany) with drug-refractory AF for treatment with PVI+RDN vs PVI alone. A multielectrode radiofrequency Spyral catheter system was used for RDN. Insertable cardiac monitors were used for continuous rhythm monitoring. The primary efficacy endpoint was ≥2 minutes of AF recurrence or repeat ablation during all follow-up. The secondary endpoints included atrial arrhythmia (AA) burden, discontinuation of class I/III antiarrhythmic drugs, and BP changes from baseline.

RESULTS

A total of 70 patients with AF (52 paroxysmal, 18 persistent) and uncontrolled hypertension were randomized (RDN+PVI, n = 34; PVI, n = 36). At 3.5 years, 26.2% and 21.4% of patients in RDN+PVI and PVI groups, respectively, were free from the primary efficacy endpoint (log rank P = 0.73). Patients with mean ≥1 h/d AA had less daily AA burden after RDN+PVI vs PVI (4.1 hours vs 9.2 hours; P = 0.016). More patients discontinued class I/III antiarrhythmic drugs after RDN+PVI vs PVI (45% vs 14%; P = 0.040). At 1 year, systolic BP changed by -17.8 ± 12.8 mm Hg and -13.7 ± 18.8 mm Hg after RDN+PVI and PVI, respectively (P = 0.43). The composite safety endpoint was not significantly different between groups.

CONCLUSIONS

In patients with AF and uncontrolled BP, RDN+PVI did not prevent AF recurrence more than PVI alone. However, RDN+PVI may reduce AF burden and antiarrhythmic drug usage, but this needs further prospective validation.

Efficacy of renal denervation as an adjunct to pulmonary vein isolation for atrial fibrillation treatment: a systematic review and meta-analysis

Aims

Catheter ablation, consisting of pulmonary vein isolation (PVI), is the most effective treatment modality for the management of symptomatic patients with atrial fibrillation (AF). Unfortunately, this procedure has a considerable relapse rate, ranging from 15 to 50% depending on AF type and other patient factors. Hypertension (HTN) is associated with a higher risk of developing AF and can also be managed with a catheter-based procedure-renal denervation (RDN). This meta-analysis aimed to compare the effect of PVI with and without RDN in hypertensive patients with AF.

Methods and results

OVID MEDLINE and Embase were searched on 1 February 2023 and trials that reported the effects of RDN on AF recurrence in hypertensive patients were included. A total of 637 patients across 8 randomised controlled trials were included. The results from the pooled analysis showed that when compared with PVI alone, RDN added to PVI: (1) Lowered AF recurrence [RR 0.67 (0.53, 0.85), P = 0.001, I 2 = 23%, NNT = 5.9 patients]; (2) Reduced both systolic blood pressure and diastolic blood pressure, with medium effect size, as reflected by standardised mean differences of 0.5 (P = 0.02, I 2 = 80%) and 0.43 (P = 0.006, I 2 = 60%), respectively; and (3) was not associated with a decrease in estimated glomerular filtration rate (+7.19 mL/min/1.73 m2, P = 0.15, I 2 = 89%).

Conclusion

Adding RDN to PVI in patients with AF and resistant HTN was associated with a reduction of blood pressure levels and AF recurrence. Consideration to RDN should be given as an adjunctive treatment for patients with AF and resistant HTN.

Lifestyle changes in atrial fibrillation management and intervention

Atrial fibrillation (AF) is one of the most common arrhythmias in adults, and its continued rise in the United States is complicated by the increased incidence and prevalence of several AF risk factors, such as obesity, physical inactivity, hypertension, obstructive sleep apnea, diabetes mellitus, coronary artery disease, and alcohol, tobacco, or caffeine use. Lifestyle and risk factor modification has been proposed as an additional pillar of AF therapy, added to rhythm control, rate control, and anticoagulation, to reduce AF burden and risk. Although emerging evidence largely supports the integration of lifestyle and risk factor management in clinical practice, randomized clinical trials investigating the long-term sustainability and reproducibility of these benefits remain sparse. The purpose of this review is to discuss potentially reversible risk factors on AF, share evidence for the impact on AF by modification of these risk factors, and then provide an overview of the effects of reversing or managing these risk factors on the success of various AF management strategies, such as antithrombotic, rate control, and rhythm control therapies.

Atrial fibrillation: primary prevention, secondary prevention, and prevention of thromboembolic complications: part 1

Atrial fibrillation (AF), is the most common sustained cardiac arrhythmia. It was once thought to be benign as long as the ventricular rate was controlled, however, AF is associated with significant cardiac morbidity and mortality. Increasing life expectancy driven by improved health care and decreased fertility rates has, in most of the world, resulted in the population aged ≥65 years growing more rapidly than the overall population. As the population ages, projections suggest that the burden of AF may increase more than 60% by 2050. Although considerable progress has been made in the treatment and management of AF, primary prevention, secondary prevention, and prevention of thromboembolic complications remain a work in progress. This narrative review was facilitated by a MEDLINE search to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, and other clinically relevant studies. The search was limited to English-language reports published between 1950 and 2021. Atrial fibrillation was searched via the terms primary prevention, hyperthyroidism, Wolff-Parkinson-White syndrome, catheter ablation, surgical ablation, hybrid ablation, stroke prevention, anticoagulation, left atrial occlusion and atrial excision. Google and Google scholar as well as bibliographies of identified articles were reviewed for additional references. In these two manuscripts, we discuss the current strategies available to prevent AF, then compare noninvasive and invasive treatment strategies to diminish AF recurrence. In addition, we examine the pharmacological, percutaneous device and surgical approaches to prevent stroke as well as other types of thromboembolic events.

Hypertension and atrial fibrillation

Hypertension is the most prevalent cardiovascular risk factor underlying atrial fibrillation and is present in up to 40% of patients with atrial fibrillation. Furthermore, attributable risk studies have shown that a history of hypertension contributes to up to 24% of incident atrial fibrillation. New data suggest that even early forms of hypertension (prehypertension and aortic stiffness) are associated with an increased risk of atrial fibrillation development. Hypertension and prehypertension are therefore critical mediators for the development of atrial fibrillation. Mechanisms for the association between hypertension and atrial fibrillation include diffuse electro-structural changes to the left atrium, driven by the haemodynamic and neurohormonal influences of hypertension and other, frequently coexisting, cardiovascular risk factors. Management of hypertension in atrial fibrillation should focus not only on blood pressure reduction but also on a comprehensive risk factor modification strategy. Such strategies have been shown to be associated with significant improvements in atrial fibrillation symptom burden as well as improved arrhythmia-free survival and reversal of the progression of atrial fibrillation. These strategies should focus on dietary modifications as well as prescribed exercise programmes involving a multidisciplinary team and patient-centred atrial fibrillation care. Risk factor management, supplemented by antihypertensive medications as needed, provides the optimum strategy for improving outcomes and even reversing the natural progression of atrial fibrillation in patients with hypertension.

Renal denervation for atrial fibrillation: a comprehensive updated systematic review and meta-analysis

The study aims to compare clinical outcomes following renal denervation (RDN) in hypertensive patients with atrial fibrillation (AF). Three online databases were searched (MEDLINE, EMBASE and PubMed) for literature related to outcomes of RDN on hypertension and AF, between January 1, 2010, and June 1, 2021. Where possible, risk ratios (RR) and mean differences (MD) were combined using a random effects model. Significance was set at p ≤ 0.05. Seven trials were included that assessed the effect of adding RDN to pulmonary vein isolation (PVI) in patients with hypertension and AF. A total of 711 patients (329 undergoing PVI + RDN and 382 undergoing PVI alone), with an age range of 56 ± 6 to 68 ± 9 years, were included. Pooled analysis showed a significant lowering of AF recurrence in the PVI + RDN (31.3%) group compared to the PVI-only (52.9%) group (p < 0.00001). Pooled analysis of patients with resistant hypertension showed a significant mean reduction of systolic blood pressure (SBP) (-9.42 mm Hg, p = 0.05), but not diastolic blood pressure (DBP) (-4.11 mm Hg, p = 0.16) in favor of PVI + RDN. Additionally, the pooled analysis showed that PVI + RDN significantly improved estimated glomerular filtration rate (eGFR) (+10.2 mL/min per 1.73 m2, p < 0.001) compared to PVI alone. RDN procedures in these trials have proven to be both safe and efficacious with an overall complication rate of 6.32%. Combined PVI and RDN is beneficial for patients with hypertension and AF. Combined therapy showed improvement in SBP and eGFR, reducing the risk of AF recurrence. RDN may serve as an innovative intervention in the treatment of AF.

Systematic review of renal denervation for the management of cardiac arrhythmias

Background

In the wake of the controversy surrounding the SYMPLICITY HTN-3 trial and data from subsequent trials, this review aims to perform an updated and more comprehensive review of the impact of renal sympathetic denervation on cardiac arrhythmias.

Methods and results

A systematic search was performed using the Medline, Scopus and Embase databases using the terms “Renal Denervation” AND “Arrhythmias or Atrial or Ventricular”, limited to Human and English language studies within the last 10 years. This search yielded 19 relevant studies (n = 6 randomised controlled trials, n = 13 non-randomised cohort studies) which comprised 783 patients. The studies show RSD is a safe procedure, not associated with increases in complications or mortality post-procedure. Importantly, there is no evidence RSD is associated with a deterioration in renal function, even in patients with chronic kidney disease. RSD with or without adjunctive pulmonary vein isolation (PVI) is associated with improvements in freedom from atrial fibrillation (AF), premature atrial complexes (PACs), ventricular arrhythmias and other echocardiographic parameters. Significant reductions in ambulatory and office blood pressure were also observed in the majority of studies.

Conclusion

This review provides evidence based on original research that ‘second generation’ RSD is safe and is associated with reductions in short-term blood pressure and AF burden. However, the authors cannot draw firm conclusions with regards to less prominent arrhythmia subtypes due to the paucity of evidence available. Large multi-centre RCTs investigating the role of RSD are necessary to comprehensively assess the efficacy of the procedure treating various arrhythmias.

Graphic abstract

Renal arteries denervation: from the treatment of resistant hypertension to the treatment of atrial fibrillation

Renal denervation (RDN) is a therapeutic strategy for patients with uncontrolled arterial hypertension characterized by considerable fluctuations during its progression. After initial strong enthusiasm, the procedure came to an abrupt halt following the publication of the Symplicity HTN-3 study results. The results of recently published studies highlight the reduction in blood pressure values after RDN and justify the inclusion in the Guidelines of new recommendations for the use of RDN in clinical practice, in selected patients. Additionally, RDN findings are summarized in view of other potential indications such as atrial fibrillation. Six prospective, randomized studies are presented that evaluated RDN as an adjunct therapy to pulmonary vein isolation for the treatment of atrial fibrillation. In five studies, patients had uncontrolled hypertension despite therapy with three antihypertensive drugs. The analysis of these studies showed that RDN reduced the recurrence of atrial fibrillation (AF) by 57% compared to patients with pulmonary vein isolation (PVI) only. Modulation of the autonomic nervous system by RDN has been shown not only to reduce blood pressure but also to have an antiarrhythmic effect in symptomatic AF patients when the strategy is combined with PVI, thus opening up new therapeutic scenarios.

Renal denervation: can we press the "ON" button again in 2020?

In December 2018, an article summarizing available results of randomized studies on renal denervation (RDN), entitled "Renal denervation: can we press the ON button again?" was published in the Advances in Interventional Cardiology. Since then, several positive reports, including SPYRAL HTN OFF-MED Pivotal trial have been presented. In the current review the authors discuss the latest data on RDN in arterial hypertension treatment and try to answer the burning question: can we press the ON button again in 2020? The results of recently published studies potentially justify new recommendations for the use of RDN in clinical practice in appropriately selected patients in the new hypertension guidelines. The current review also summarizes the results of trials on RDN applied in another potential indication - atrial fibrillation. Six most important, prospective, randomized trials assessing RDN as adjunct therapy to pulmonary vein isolation for treatment of atrial fibrillation were discussed. In 5 studies, patients had uncontrolled BP despite treatment with three antihypertensive agents. The ratio for recurrence of atrial fibrillation for pulmonary vein isolation with RDN procedure was reduced by 57% as compared to pulmonary vein isolation (PVI) alone. BP was also reduced significantly after RDN in this subset of patients. Further multicenter studies involving standardized PVI and RDN procedures are needed.

Effect of combined renal denervation and pulmonary vein isolation in atrial fibrillation recurrence in hypertensive patients: A meta-analysis

BACKGROUND

Atrial Fibrillation (AF) is the most common cardiac arrhythmia and hypertension is the most common risk factor associated with AF. The addition of renal sympathetic nerve denervation (RSDN) to pulmonary vein isolation (PVI) in AF patients with hypertension has been reported to improve clinical outcomes.

METHODS

A systematic search was performed for studies on patients with AF and hypertension that compared RSDN with PVI versus PVI-alone. Risk ratio (RR) for categorical variables and mean difference (MD) for continuous variables with 95% confidence intervals were used.

RESULTS

Seven studies with a total of 734 patients were included. A total of 340 patients were in the RSDN + PVI group (46.32%) and 394 (53.67%) in the PVI group. A total of 608 patients had paroxysmal AF (83%) while 126 patients had persistent AF (17%). At 12 months follow-up, RSDN + PVI decreased the overall risk of AF recurrence in hypertensive patients with RR 0.60 [95% CI 0.50-0.72, P < .00001]. A subgroup analysis performed in patients with drug-resistant hypertension showed a similar reduction in AF recurrence with RR 0.61 [95% CI: 0.47-0.79, P = .0002). Procedure duration MD + 28.05 min [95% CI: 18.88-37.23, P < .00001] and fluoroscopy duration MD + 5.59 min [95% CI: 3.31-8.19, P < .00001] were significantly longer with the RSDN + PVI group. There was no significant difference in complications between the two groups.

CONCLUSION

The addition of RSDN to PVI in patients with AF and hypertension appears safe and decreases AF recurrence. Similar results were observed in patients with drug-resistant hypertension. Larger trials are needed to confirm these results.

Role of Ganglionated Plexus Ablation in Atrial Fibrillation on the Basis of Supporting Evidence

The role of the autonomic nervous system (ANS) in the onset and maintenance of atrial fibrillation (AF) may be related to autonomic imbalance. The ANS may cause specific cellular electrophysiological phenomena, such as, shortening of the atrial effective refractory periods (ERPs) and ectopy based on firing activity in pulmonary vein myocytes. High frequency stimulation of atrial ganglionated plexi (GPs) may cause an increase in ERP dispersion and induce AF. Autonomic modification strategies by targeting GPs with catheter ablation have emerged as new targets. Various strategies have been used to detect location of GPs.However, it is still not clear which is the best method to localize GPs, how many GPs should be targeted, and what are the long-term consequences of these therapies. In this review, we discuss available evidence on the clinical impact of GP ablation to treat AF.

Efficacy and safety of renal denervation in addition to pulmonary vein isolation for atrial fibrillation and hypertension-Systematic review and meta-analysis of randomized controlled trials

Introduction

This systematic review and meta‐analysis aimed to assess the latest evidence on the use of renal denervation (RDN) + pulmonary vein isolation (PVI) compared to PVI alone for treating atrial fibrillation (AF) with hypertension.

Methods

A systematic literature search from several electronic databases was performed up until January 2020. The primary outcome was AF recurrence defined as AF/atrial flutter (AFL)/atrial tachycardia (AT) ≥30 seconds at 12‐month follow‐up and the secondary outcome was procedure‐related complications.

Results

There were 568 subjects from five studies. AF recurrence was 90/280 (32.1%) in the RDN + PVI group and 142/274 (51.8%) in the PVI group. RDN + PVI was associated with a lower incidence of AF recurrence (RR 0.62 [0.51, 076], P < .001; I²: 0%). Pooled analysis of HR showed that RDN + PVI was associated with reduced AF recurrence (HR 0.51 [0.38, 0.70], P < .001; I²: 0%). Complications were 7/241 (2.9%) in the RDN + PVI group and 8/237 (3.4%) in the PVI group. The rate of complications between the groups was similar (RR 0.87 [0.33, 2.29], P = .77; I²: 0%). In the subgroup analysis of paroxysmal AF, RDN + PVI was shown to reduce AF recurrence (RR 0.64 [0.49, 0.82], P < .001; I²: 0% and HR 0.56 [0.38, 0.82], P = .003; I²: 0%) compared to PVI alone. RDN + PVI has a moderate certainty of evidence in the reducing AF recurrence with an absolute reduction of 197 fewer per 1000 (from 254 fewer to 124 fewer).

Conclusion

RDN in addition to PVI, is associated with reduced 12‐month AF recurrence and similar procedure‐related complications compared to PVI alone.

Lifestyle and Risk Factor Modification for Reduction of Atrial Fibrillation: A Scientific Statement From the American Heart Association

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, is associated with substantial morbidity, mortality, and healthcare use. Great strides have been made in stroke prevention and rhythm control strategies, yet reducing the incidence of AF has been slowed by the increasing incidence and prevalence of AF risk factors, including obesity, physical inactivity, sleep apnea, diabetes mellitus, hypertension, and other modifiable lifestyle-related factors. Fortunately, many of these AF drivers are potentially reversible, and emerging evidence supports that addressing these modifiable risks may be effective for primary and secondary AF prevention. A structured, protocol-driven multidisciplinary approach to integrate lifestyle and risk factor management as an integral part of AF management may help in the prevention and treatment of AF. However, this aspect of AF management is currently underrecognized, underused, and understudied. The purpose of this American Heart Association scientific statement is to review the association of modifiable risk factors with AF and the effects of risk factor intervention. Implementation strategies, care pathways, and educational links for achieving impactful weight reduction, increased physical activity, and risk factor modification are included. Implications for clinical practice, gaps in knowledge, and future directions for the research community are highlighted.

Neuroscience in the heart: Recent advances in neurocardiac communication and its role in cardiac arrhythmias

Autonomic nervous system dysregulation is involved in the pathophysiology of multiple cardiac arrhythmias, and therefore modulating sympathetic or parasympathetic input to the heart provides novel therapeutic options for arrhythmia management. Examples include decreasing intrinsic cardiac neuron communication, patterned vagal nerve stimulation, denervation, and blockade of post-ganglionic neurons. However, lessons from ventricular arrhythmias, where increased sympathetic activity and vagal rebound activity both amplify arrhythmia risk, stress the importance of understanding the regulatory mechanisms that modulate the balance and levels of sympathetic and parasympathetic activity. Of critical need is an increased understanding of plasticity mechanisms in the autonomic nervous system, to a level similar to what is known in the central nervous system, in order to develop safe and effective neuromodulatory therapies.

Resistant Hypertension: Novel Insights

Hypertension is the most common chronic disease and the leading risk factor for disability and premature deaths in the world, accounting for more than 9 million deaths annually. Resistant hypertension is a particularly severe form of hypertension. It was described 50 years ago and since then has been a very active field of research. This review aims at summarizing the most recent findings on resistant hypertension. The recent concepts of apparent- and true-resistant hypertension have stimulated a more precise definition of resistant hypertension taking into account not only the accuracy of blood pressure measurement and pharmacological class of prescribed drugs but also patient adherence to drugs and life-style recommendations. Recent epidemiological studies have reported a 10% prevalence of resistant hypertension among hypertensive subjects and demonstrated the high cardiovascular risk of these patients. In addition, these studies identified subgroups of patients with even higher morbidity and mortality risk, probably requiring a more aggressive medical management. In the meantime, guidelines provided more standardized clinical work-up to identify potentially reversible causes for resistant hypertension such as secondary hypertension. The debate is however still ongoing on which would be the optimal method(s) to screen for non-adherence to hypertension therapy, recognized as the major cause for (pseudo)-resistance to treatment. Recent randomized clinical trials have demonstrated the strong benefit of anti-aldosterone drugs (mostly spironolocatone) as fourth-line therapies in resistant hypertension whereas clinical trials with device-based therapies displayed contrasting results. New trials with improved devices and more carefully selected patients with resistant hypertension are ongoing.

Neuromodulation for the Treatment of Heart Rhythm Disorders

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Derangement of autonomic nervous signaling is an important contributor to cardiac arrhythmogenesis.

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Modulation of autonomic nervous signaling holds significant promise for the prevention and treatment of cardiac arrhythmias.

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Further clinical investigation is necessary to establish the efficacy and safety of autonomic modulatory therapies in reducing cardiac arrhythmias.

There is an increasing recognition of the importance of interactions between the heart and the autonomic nervous system in the pathophysiology of arrhythmias. These interactions play a role in both the initiation and maintenance of arrhythmias and are important in both atrial and ventricular arrhythmia. Given the importance of the autonomic nervous system in the pathophysiology of arrhythmias, there has been notable effort in the field to improve existing therapies and pioneer additional interventions directed at cardiac-autonomic targets. The interventions are targeted to multiple and different anatomic targets across the neurocardiac axis. The purpose of this review is to provide an overview of the rationale for neuromodulation in the treatment of arrhythmias and to review the specific treatments under evaluation and development for the treatment of both atrial fibrillation and ventricular arrhythmias.

Hypertension and Atrial Fibrillation: Doubts and Certainties From Basic and Clinical Studies

Hypertension and atrial fibrillation (AF) are 2 important public health priorities. Their prevalence is increasing worldwide, and the 2 conditions often coexist in the same patient. Hypertension and AF are strikingly related to an excess risk of cardiovascular disease and death. Hypertension ultimately increases the risk of AF, and because of its high prevalence in the population, it accounts for more cases of AF than other risk factors. Among patients with established AF, hypertension is present in about 60% to 80% of individuals. Despite the well-known association between hypertension and AF, several pathogenetic mechanisms underlying the higher risk of AF in hypertensive patients are still incompletely known. From an epidemiological standpoint, it is unclear whether the increasing risk of AF with blood pressure (BP) is linear or threshold. It is uncertain whether an intensive control of BP or the use of specific antihypertensive drugs, such as those inhibiting the renin-angiotensin-aldosterone system, reduces the risk of subsequent AF in hypertensive patients in sinus rhythm. Finally, in spite of the observational evidence suggesting a progressive relation between BP levels and the risk of thromboembolism and bleeding in patients with hypertension and AF, the extent to which BP should be lowered in these patients, including those who undergo catheter ablation, remains uncertain. This article summarizes the main basic mechanisms through which hypertension is believed to promote AF. It also explores epidemiological data supporting an evolutionary pathway from hypertension to AF, including the emerging evidence favoring an intensive BP control or the use of drugs, which inhibit the renin-angiotensin-aldosterone system to reduce the risk of AF. Finally, it examines the impact of non-vitamin K antagonist oral anticoagulants compared with warfarin in relation to hypertension.

Sympathetic Nervous System Activation and Its Modulation: Role in Atrial Fibrillation

The autonomic nervous system (ANS) has a significant influence on the structural integrity and electrical conductivity of the atria. Aberrant activation of the sympathetic nervous system can induce heterogeneous changes with arrhythmogenic potential which can result in atrial tachycardia, atrial tachyarrhythmias and atrial fibrillation (AF). Methods to modulate autonomic activity primarily through reduction of sympathetic outflow reduce the incidence of spontaneous or induced atrial arrhythmias in animal models and humans, suggestive of the potential application of such strategies in the management of AF. In this review we focus on the relationship between the ANS, sympathetic overdrive and the pathophysiology of AF, and the potential of sympathetic neuromodulation in the management of AF. We conclude that sympathetic activity plays an important role in the initiation and maintenance of AF, and modulating ANS function is an important therapeutic approach to improve the management of AF in selected categories of patients. Potential therapeutic applications include pharmacological inhibition with central and peripheral sympatholytic agents and various device based approaches. While the role of the sympathetic nervous system has long been recognized, new developments in science and technology in this field promise exciting prospects for the future.

Atrial fibrillation reduction by renal sympathetic denervation: 12 months' results of the AFFORD study

Aim

The purpose of this pilot study was to assess whether renal sympathetic denervation (RDN) decreases atrial fibrillation (AF) burden in hypertensive patients with symptomatic AF at 6- and 12-month follow-up, as measured using an implantable cardiac monitor (ICM).

Methods and results

A total of 20 patients with symptomatic paroxysmal or persistent AF (EHRA ≥ II) and primary hypertension with a mean office systolic blood pressure (BP) of > 140 mmHg were enrolled. After enrolment, an ICM was implanted 3 months pre-RDN to monitor AF burden. Quality of life (QOL) was assessed using the Atrial Fibrillation Effect on QualiTy-of-life (AFEQT) questionnaire. Mean age was 64 ± 7 years and 55% were females. AF burden in min/day decreased from a median (IQR) of 1.39 (0–11) pre-RDN to 0.67 (0–31.6) at 6 months (p = 0.64) and to 0.94 (0–6.0) at 12 months (pre-RDN vs. 12 months; p = 0.03). QOL improved significantly at both 6 months (+ 11 ± 15 points, p = 0.006) and 12 months (+ 10 ± 19, p = 0.04) as compared to pre-RDN. Office BP decreased significantly at 12-month follow-up (− 20 ± 19/− 7 ± 10 mmHg), p < 0.01) as compared to pre-RDN. Ambulatory BP decreased − 7 ± 16/− 3 ± 9 mmHg (p > 0.05) at 12-month follow-up as compared to pre-RDN.

Conclusion

This pilot study suggests that RDN might be able to decrease AF burden in min/day as measured using an ICM, with a positive effect on QOL. Large-scale randomized trials are needed to prove the definite value of RDN in hypertensive patients with atrial fibrillation.

Electronic supplementary material

The online version of this article (10.1007/s00392-018-1391-3) contains supplementary material, which is available to authorized users.

Treatment of atrial fibrillation in patients with enhanced sympathetic tone by pulmonary vein isolation or pulmonary vein isolation and renal artery denervation: clinical background and study design : The ASAF trial: ablation of sympathetic atrial fibrillation

BACKGROUND

Hypertension is an important, modifiable risk factor for the development of atrial fibrillation (AF). Even after pulmonary vein isolation (PVI), 20-40% experience recurrent AF. Animal studies have shown that renal denervation (RDN) reduces AF inducibility. One clinical study with important limitations suggested that RDN additional to PVI could reduce recurrent AF.

OBJECTIVE

The goal of this multicenter randomized controlled study is to investigate whether RDN added to PVI reduces AF recurrence.

METHODS

The main end point is the time until first AF recurrence according to EHRA guidelines after a blanking period of 3 months. Assuming a 12-month accrual period and 12 months of follow-up, a power of 0.80, a two-sided alpha of 0.05 and an expected drop-out of 10% per group, 69 patients per group are required. We plan to randomize a total of 138 hypertensive patients with AF and signs of sympathetic overdrive in a 1:1 fashion. Patients should use at least two antihypertensive drugs. Sympathetic overdrive includes obesity, exercise-induced excessive blood pressure (BP) increase, significant white coat hypertension, hospital admission or fever induced AF, tachycardia induced AF and diabetes mellitus. The interventional group will undergo PVI + RDN and the control group will undergo PVI.

RESULTS

Patients will have follow-up for 1 year, and continuous loop monitoring is advocated.

CONCLUSION

This randomized, controlled study will elucidate if RDN on top of PVI reduces AF recurrence.

Modulation of renal sympathetic innervation: recent insights beyond blood pressure control

Renal afferent and efferent sympathetic nerves are involved in the regulation of blood pressure and have a pathophysiological role in hypertension. Additionally, several conditions that frequently coexist with hypertension, such as heart failure, obstructive sleep apnea, atrial fibrillation, renal dysfunction, and metabolic syndrome, demonstrate enhanced sympathetic activity. Renal denervation (RDN) is an approach to reduce renal and whole body sympathetic activation. Experimental models indicate that RDN has the potential to lower blood pressure and prevent cardio-renal remodeling in chronic diseases associated with enhanced sympathetic activation. Studies have shown that RDN can reduce blood pressure in drug-naïve hypertensive patients and in hypertensive patients under drug treatment. Beyond its effects on blood pressure, sympathetic modulation by RDN has been shown to have profound effects on cardiac electrophysiology and cardiac arrhythmogenesis. RDN can display anti-arrhythmic effects in a variety of animal models for atrial fibrillation and ventricular arrhythmias. The first non-randomized studies demonstrate that RDN may promote the maintenance of sinus rhythm following catheter ablation in patients with atrial fibrillation. Registry data point towards a beneficial effect of RDN to prevent ventricular arrhythmias in patients with heart failure and electrical storm. Further large randomized placebo-controlled trials are needed to confirm the antihypertensive and anti-arrhythmic effects of RDN. Here, we will review the current literature on anti-arrhythmic effects of RDN with the focus on atrial fibrillation and ventricular arrhythmias. We will discuss new insights from preclinical and clinical mechanistic studies and possible clinical implications of RDN.

Pulmonary vein isolation combined with spironolactone or renal sympathetic denervation in patients with chronic kidney disease, uncontrolled hypertension, paroxysmal atrial fibrillation, and a pacemaker

BACKGROUND

Atrial fibrillation (AF) commonly occurs in chronic kidney disease (CKD), occasioning adverse outcomes. Merging pulmonary vein isolation (PVI) and renal sympathetic denervation (RSD) may decrease the recurrence of AF in subjects with CKD and uncontrolled hypertension. We considered that RSD could reduce the recurrence of AF in patients with CKD by modulating sympathetic hyperactivity. We aimed to evaluate the impact of RSD or spironolactone 50 mg/day associated with PVI in reducing systolic blood pressure (BP), AF recurrence, and AF burden in patients with a history of paroxysmal AF and mild CKD.

METHODS

This was a single-center, prospective, longitudinal, randomized, double-blind study. The individuals were randomly divided into two groups (PVI + spironolactone, n = 36, and PVI + RSD, n = 33). All of them were followed for exactly 1 year to assess maintenance of sinus rhythm and to monitor the other variables.

RESULTS

Ambulatory BP measurements were reduced in both groups and at the 12th month also differed between groups. Significantly more patients in the PVI + RSD (61%) than in the PVI + spironolactone group (36%) were AF-free at the 12th month of follow-up, P = 0.0242. Toward the end of the study, the mean AF burden was lower in the PVI + RSD group as compared to PVI + spironolactone group, at the 9th month: ∆ = - 10% (P < 0.0001), and at the 12th month: ∆ = - 12% (P < 0.0001), respectively.

CONCLUSIONS

PVI + RSD is safe and appears to be superior to PVI + spironolactone in BP reduction, augmentation of AF event-free rate, reduction of AF burden, and improvement of renal function.