Moderate physical exercise: a simplified approach for ventricular rate control in older patients with atrial fibrillation

Effects of exercise intervention on exercise capacity and cardiopulmonary function in patients with atrial fibrillation: A randomized controlled trial systematic review and meta-analysis

BACKGROUND

Atrial fibrillation (AF) is a common cardiac arrhythmia that significantly impacts the cardiopulmonary function and quality of life of patients. Despite various treatment strategies, non-pharmacological interventions, particularly exercise interventions, have gained attention in recent years.

OBJECTIVE

Through systematic review and meta-analysis, this study explores the impact of physical activity on the exercise capacity and quality of life of AF patients. It assesses the safety, clinical outcomes, and physiological mechanisms of exercise intervention in the treatment of AF.

METHODS

The systematic review and individual patient data (IPD) meta-analysis method were employed, following the PRISMA-IPD guidelines, for literature selection, data extraction, and quality assessment. The analysis focused on the impact of exercise on the cardiopulmonary function and quality of life of AF patients in randomized controlled trials.

RESULTS

A total of 12 randomized controlled trials involving 287 AF patients were included. Meta-analysis demonstrated a significant improvement in the 6-minute walk test capacity (SMD=87.87, 95% CI [42.23, 133.51]), static heart rate improvement (SMD=-7.63, 95% CI [-11.42, -3.85]), and cardiopulmonary function enhancement (SMD=2.37, 95% CI [0.96, 3.77]) due to exercise. There was also a significant improvement in the quality of life (SMD=0.720, 95% CI [0.038, 1.402]).

CONCLUSION

Exercise has a significant effect on improving exercise capacity and cardiopulmonary function in patients with atrial fibrillation. Particularly, high-intensity exercise training has a more significant impact on improving cardiopulmonary function and exercise capacity, emphasizing the importance of personalized exercise plans in enhancing the cardiopulmonary health of AF patients. Further research is needed to explore the effects of exercise on improving the quality of life in the future.

PROSPERO ID

CRD2023493917.

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.

Exercise training in the treatment of paroxysmal atrial fibrillation: study protocol of the Cologne ExAfib Trial

INTRODUCTION

Atrial fibrillation (AF) is the most common form of cardiac arrhythmia and is associated with a number of comorbidities such as coronary artery disease and heart failure. While physical activity is already implemented in current international guidelines for the prevention and treatment of AF, the precise role of different types of exercise in the management of AF remains to be elucidated. The primary aim of the Cologne ExAfib Trial is to assess the feasibility and safety of different exercise modes in patients diagnosed with paroxysmal AF. Secondary outcomes include assessments of physical function, AF burden, quality of life and inflammation, as well as morphological and cardiac adaptations.

METHODS AND ANALYSIS

The study opened for recruitment in September 2019. In the initial pilot phase of this four-armed randomised controlled trial, we aim to enrol 60 patients between 60 years and 80 years of age with paroxysmal AF. After screening and pretesting, patients are randomised into one of the following groups: high-intensity interval training (4×4 min at 75%-85% peak power output (PPO)), moderate-intensity continuous training (25 min at 55%-65% PPO), strength training (whole body, 3 sets of 6-12 repetitions at 70%-90% one repetition maximum [1RM]) or a usual-care control group. Training is performed two times per week for 12 weeks. If the feasibility and safety can be confirmed through the initial pilot phase, the recruitment will be continued and powered for a clinical endpoint.Feasibility and safety are assessed by measures of recruitment and completion, programme tolerance and adherence as well as reported adverse events, including hospitalisation rates. Secondary endpoints are assessed by measures of peak oxygen consumption and the 1RM of selected muscle groups, questionnaires concerning quality of life and AF burden, serum blood samples for the analysis of C reactive protein, interleukin-6, tumour necrosis factor alpha and N-terminal pro-brain natriuretic peptide concentrations and ultrasound for muscle and heart morphology as well as cardiac function.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the ethics committee of the German Sport University Cologne (No.: 175/2018). All procedures performed in studies involving human participants are in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Manuscripts will be written based on international authorship guidelines. No professional writers will be commissioned for manuscript drafting. The findings of this study will be published in peer-reviewed journals and presented at leading exercise and medicine conferences TRIAL REGISTRATION NUMBER: The study is registered both at the German and at the WHO trial registers (DRKS00016637); Pre-results.

Efficacy of Physical Exercise on the Quality of Life, Exercise Ability, and Cardiopulmonary Fitness of Patients With Atrial Fibrillation: A Systematic Review and Meta-Analysis

Objective: Physical exercise is recommended to help prevent lifestyle diseases. The present study was designed to quantify the efficacy of physical exercise on the quality of life (QoL), exercise ability and cardiopulmonary fitness of patients with atrial fibrillation (AF).

Method: A comprehensive systematic literature search was performed in Medline, Embase, Cochrane Library, Web of Science and PubMed databases (from 1970 to December 1st, 2019) for randomized controlled trials (RCTs) comparing physical exercise combined with AF routine treatments to routine treatments alone. The meta-analysis was conducted following PRISMA guidelines. Our main outcomes were QoL (measured by the Short-Form 36 scale, SF-36), exercise ability (measured by the 6-min walk test, 6MWT) and cardiopulmonary fitness (measured by peak oxygen uptake and resting heart rate). Quality assessments were conducted using the Cochrane Collaboration tool.

Results: Twelve trials involving 819 patients met the criteria for analysis. The results showed that physical exercise improved the QoL by enhancing physical functioning [standardized mean difference (SMD) = 0.63, 95%CI: 0.18–1.09; p = 0.006], general health perceptions (SMD = 0.64, 95%CI: 0.35–0.93; p < 0.001) and vitality (SMD = 0.51, 95%CI: 0.31–0.71; p < 0.001); increased exercise ability by improving the 6MWT performance (SMD = 0.69, 95%CI: 0.19–1.119; p = 0.007); and enhanced peak VO₂ (SMD = 0.37, 95%CI: 0.16–0.57; p < 0.001) while reducing resting heart rate (SMD = −0.39, 95%CI: −0.65 to −0.13; p = 0.004). In addition, meta-regression analysis showed that training mode (p_{physicalfunctioning} = 0.012, p_{generalhealthperceptions} = 0.035) and training duration (p = 0.047) were the main factors of an intervention that influenced the effect size. Following sub-group analysis, we found that aerobics, Yoga and longer training durations (≥60 min) showed larger improvements.

Conclusion: In summary, our meta-analysis shows that physical exercise has a positive effect on the QoL, exercise ability and cardiopulmonary fitness in AF patients. When physicians offer exercise recommendations to AF patients, they should consider both the training mode and training duration to achieve maximum results.

Physical activity and serious adverse events in patients with atrial fibrillation and/or atrial flutter treated with catheter ablation

BACKGROUND

Atrial fibrillation (AF) and atrial flutter (AFL) are cardiac arrhythmias associated with cardiovascular morbidity. Physical activity (PA) can trigger AF and AFL recurrence, but can also improve physical functional capacity in this patient group. Guidelines do not include concrete recommendations regarding PA for this patient group.

OBJECTIVE

To assess the impact of the level of PA on risk of serious adverse events (SAEs) in patients with AF and/or AFL treated with catheter ablation.

METHODS

A prospective cohort study including 462 patients with AF and/or AFL treated with catheter ablation from the CopenHeart Survey. The International Physical Activity Questionnaire (IPAQ) was used to explore patients' self-reported level of PA. SAEs were identified in the Danish National Patient Register and the Danish Civil Registration System one year after study onset. Cox regression analysis was carried out to assess the risks of SAE.

RESULTS

During the one-year follow-up period, 98 patients (21.8%) experienced at least one SAE. Patients with a moderate-high PA level had a 36% lower risk of experiencing SAEs during the follow-up period, compared to patients in the low PA group, after adjusting for confounders.

CONCLUSION

A moderate-high vs. low level of PA was found to be associated with a lower incidence of SAEs in patients undergoing AF and/or AFL ablation.

Exercise Testing and Exercise Rehabilitation for Patients With Atrial Fibrillation

INTRODUCTION AND PURPOSE

Atrial fibrillation (AF) is a common cardiac arrhythmia associated with an increasing prevalence with advancing age. It is associated with dyspnea, exercise intolerance, and increased risk for clinical events, especially stroke and heart failure. This article provides a concise review of exercise testing and rehabilitation in patients with persistent or permanent AF.

CLINICAL CONSIDERATIONS

The first goal in the treatment of AF is to reduce symptoms (eg, palpitations) and a fast ventricular rate. The second goal is to reduce the risk of a stroke. Exercise testing and rehabilitation may be useful once these goals are achieved. However, there are no large, randomized exercise training trials involving patients with AF, and what data are available comes from single-site trials, secondary analyses, and observational studies.

EXERCISE TESTING AND TRAINING

There are no specific indications for performing a graded exercise test in patients with AF; however, such testing may be used to screen for myocardial ischemia or evaluate chronotropic response during exertion. Among patients with AF, exercise capacity is 15% to 20% lower and peak heart rate is higher than in patients in sinus rhythm. Exercise rehabilitation improves exercise capacity, likely improves quality of life, and may improve symptoms associated with AF. Whole-body aerobic exercise is recommended.

SUMMARY

Atrial fibrillation is a common cardiac condition and in these patients, exercise rehabilitation favorably improves exercise capacity. However, prospective randomized controlled trials are needed to better define the effects of exercise training on safety; quality of life; clinical outcomes; and central, autonomic, and peripheral adaptations.

Lifestyle Therapy for the Management of Atrial Fibrillation

Atrial fibrillation (AF) is a common arrhythmia associated with increased risk of morbidity and mortality. There is evidence that lifestyle interventions may serve as complementary treatments to reduce AF burden. The objective of this review was to summarize the efficacy of lifestyle interventions for the management of AF. Studies which included patients with systolic heart failure (ejection fraction ≤40%), and those limited to an examination of vigorous physical activity were excluded from our search. Studies were identified through a search of the following databases: MEDLINE, EMBASE, CINAHIL, and PubMed, run from inception through August 2016. All studies were graded for quality using the Oxford Centre for Evidence-based Medicine recommendations. Meta-analyses of the studies were not performed due to the heterogeneity of the studies. From a total of 1,811 publications, 10 articles were identified and included. Selected publications included 1 study on yoga, 2 studies on acupuncture, 3 studies that examined weight loss programs, and 4 studies that evaluated the impact of moderate physical activity. Yoga was associated with less symptomatic AF episodes and improved quality of life. Acupuncture was associated with reduced AF occurrence in patients with persistent and paroxysmal AF. Weight loss was associated with a significant reduction AF burden and symptoms. Moderate exercise resulted in greater arrhythmia free survival and a mean reduction in AF burden. In conclusion, evidence exists to suggest that yoga, weight loss, and moderate exercise are associated with reductions in AF burden and symptoms. Evidence is greatest for weight loss and moderate exercise.

Exercise Training in Patients With Chronic Heart Failure and Atrial Fibrillation

BACKGROUND

The safety and efficacy of aerobic exercise in heart failure (HF) patients with atrial fibrillation (AF) has not been well evaluated.

OBJECTIVES

This study examined whether outcomes with exercise training in HF vary according to AF status.

METHODS

HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) randomized 2,331 ambulatory HF patients with ejection fraction ≤35% to exercise training or usual care. We examined clinical characteristics and outcomes (mortality/hospitalization) by baseline AF status (past history of AF or AF on baseline electrocardiogram vs. no AF) using adjusted Cox models and explored an interaction with exercise training. We assessed post-randomization AF events diagnosed via hospitalizations for AF and reports of serious arrhythmia caused by AF.

RESULTS

Of 2,292 patients with baseline rhythm data, 382 (17%) had AF, 1,602 (70%) had sinus rhythm, and 308 (13%) had "other" rhythm. Patients with AF were older and had lower peak Vo₂. Over a median follow-up of 2.6 years, AF was associated with a 24% per year higher rate of mortality/hospitalization (hazard ratio [HR]: 1.53; 95% confidence interval [CI]: 1.34 to 1.74; p < 0.001) in unadjusted analysis; this did not remain significant after adjustment (HR: 1.15; 95% CI: 0.98 to 1.35; p = 0.09). There was no significant difference in AF event rates by randomized treatment assignment in the overall population or by baseline AF status (all p > 0.10). There was no interaction between AF and exercise training on measures of functional status or clinical outcomes (all p > 0.10).

CONCLUSIONS

AF in patients with chronic HF was associated with older age, reduced exercise capacity at baseline, and a higher overall rate of clinical events, but not a differential response to exercise training for clinical outcomes or changes in exercise capacity. (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training [HF-ACTION]; NCT00047437).

Cardiovascular exercise and burden of arrhythmia in patients with atrial fibrillation - A randomized controlled trial

Background

Physical activity at moderate-high intensity is recommended to prevent lifestyle diseases. Patients with atrial fibrillation are at risk of a sedentary lifestyle due to fear of exercise-induced episodes of atrial fibrillation. The burden of arrhythmia can be reduced by physical exercise. The effect of exercise intensity on burden of atrial fibrillation needs to be studied further.

Methods and results

In a 12-week randomized controlled trial, 76 patients with paroxysmal/persistent atrial fibrillation were allocated to perform exercise at either low intensity or high intensity (50% and 80% of maximal perceived exertion, respectively). Primary outcome was burden of AF measured by daily electrocardiography-reporting during 12 weeks. Secondarily, change in maximal oxygen uptake (peak VO₂) and 1-year hospitalization was compared between low and high intensity exercise. Sixty-three patients completed the follow-up. In the intention-to-treat analysis, we found no statistical difference in burden of atrial fibrillation between low and high intensity exercise (incidence rate ratio 0.742, 95% CI 0.29–1.91, P = 0.538). No serious adverse events were reported and there was no difference in hospitalization between the two exercise groups. Both exercise groups improved significantly in peak VO₂ (low intensity: 3.62 mL O₂/kg/min, SD 3.77; high intensity: 2.87 mL O₂/kg/min, SD 4.98), with no statistical difference between-groups (mean difference: 0.76 mL O₂/kg/min, 95% CI -3.22–1.7).

Conclusions

High intensity physical exercise was not superior to low intensity physical exercise in reducing burden of atrial fibrillation. HI exercise was well tolerated; no evidence of an increased risk was found for HI compared to LI exercise. Larger studies are required to further prove our findings.

Trial registration

ClinicalTrials.gov NCT01817998

Exercise-based cardiac rehabilitation for adults with atrial fibrillation

BACKGROUND

Exercise-based cardiac rehabilitation may benefit adults with atrial fibrillation or those who had been treated for atrial fibrillation. Atrial fibrillation is caused by multiple micro re-entry circuits within the atrial tissue, which result in chaotic rapid activity in the atria.

OBJECTIVES

To assess the benefits and harms of exercise-based rehabilitation programmes, alone or with another intervention, compared with no-exercise training controls in adults who currently have AF, or have been treated for AF.

SEARCH METHODS

We searched the following electronic databases; CENTRAL and the Database of Abstracts of Reviews of Effectiveness (DARE) in the Cochrane Library, MEDLINE Ovid, Embase Ovid, PsycINFO Ovid, Web of Science Core Collection Thomson Reuters, CINAHL EBSCO, LILACS Bireme, and three clinical trial registers on 14 July 2016. We also checked the bibliographies of relevant systematic reviews identified by the searches. We imposed no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCT) that investigated exercise-based interventions compared with any type of no-exercise control. We included trials that included adults aged 18 years or older with atrial fibrillation, or post-treatment for atrial fibrillation.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data. We assessed the risk of bias using the domains outlined in the Cochrane Handbook for Systematic Reviews of Interventions. We assessed clinical and statistical heterogeneity by visual inspection of the forest plots, and by using standard Chi² and I² statistics. We performed meta-analyses using fixed-effect and random-effects models; we used standardised mean differences where different scales were used for the same outcome. We assessed the risk of random errors with trial sequential analysis (TSA) and used the GRADE methodology to rate the quality of evidence, reporting it in the 'Summary of findings' table.

MAIN RESULTS

We included six RCTs with a total of 421 patients with various types of atrial fibrillation. All trials were conducted between 2006 and 2016, and had short follow-up (eight weeks to six months). Risks of bias ranged from high risk to low risk.The exercise-based programmes in four trials consisted of both aerobic exercise and resistance training, in one trial consisted of Qi-gong (slow and graceful movements), and in another trial, consisted of inspiratory muscle training.For mortality, very low-quality evidence from six trials suggested no clear difference in deaths between the exercise and no-exercise groups (relative risk (RR) 1.00, 95% confidence interval (CI) 0.06 to 15.78; participants = 421; I² = 0%; deaths = 2). Very low-quality evidence from five trials suggested no clear difference between groups for serious adverse events (RR 1.01, 95% CI 0.98 to 1.05; participants = 381; I² = 0%; events = 8). Low-quality evidence from two trials suggested no clear difference in health-related quality of life for the Short Form-36 (SF-36) physical component summary measure (mean difference (MD) 1.96, 95% CI -2.50 to 6.42; participants = 224; I² = 69%), or the SF-36 mental component summary measure (MD 1.99, 95% CI -0.48 to 4.46; participants = 224; I² = 0%). Exercise capacity was assessed by cumulated work, or maximal power (Watt), obtained by cycle ergometer, or by six minute walking test, or ergospirometry testing measuring VO2 peak. We found moderate-quality evidence from two studies that exercise-based rehabilitation increased exercise capacity, measured by VO2 peak, more than no exercise (MD 3.76, 95% CI 1.37 to 6.15; participants = 208; I² = 0%); and very low-quality evidence from four studies that exercise-based rehabilitation increased exercise capacity more than no exercise, measured by the six-minute walking test (MD 75.76, 95% CI 14.00 to 137.53; participants = 272; I² = 85%). When we combined the different assessment tools for exercise capacity, we found very low-quality evidence from six trials that exercise-based rehabilitation increased exercise capacity more than no exercise (standardised mean difference (SMD) 0.86, 95% CI 0.46 to 1.26; participants = 359; I² = 65%). Overall, the quality of the evidence for the outcomes ranged from moderate to very-low.

AUTHORS' CONCLUSIONS

Due to few randomised patients and outcomes, we could not evaluate the real impact of exercise-based cardiac rehabilitation on mortality or serious adverse events. The evidence showed no clinically relevant effect on health-related quality of life. Pooled data showed a positive effect on the surrogate outcome of physical exercise capacity, but due to the low number of patients and the moderate to very low-quality of the underpinning evidence, we could not be certain of the magnitude of the effect. Future high-quality randomised trials are needed to assess the benefits and harms of exercise-based cardiac rehabilitation for adults with atrial fibrillation on patient-relevant outcomes.

Developing an Adapted Cardiac Rehabilitation Training for Home Care Clinicians: PATIENT PERSPECTIVES, CLINICIAN KNOWLEDGE, AND CURRICULUM OVERVIEW

PURPOSE

There is limited evidence that home care clinicians receive education on the core competencies of cardiac rehabilitation (CR). This article describes the development and implementation of a CR training program adapted for home care clinicians, which incorporated the viewpoints of homebound patients with cardiovascular disease.

METHODS

Literature and guideline reviews were performed to glean curriculum content, supplemented with themes identified among patients and clinicians. Semistructured interviews were conducted with homebound patients regarding their perspectives on living with cardiovascular disease and focus groups were held with home care clinicians regarding their perspectives on caring for these patients. Transcripts were analyzed with the constant comparative method. A 15-item questionnaire was administered to home care nurses and rehabilitation therapists pre- and posttraining, and responses were analyzed using a paired sample t test.

RESULTS

Three themes emerged among patients: (1) awareness of heart disease; (2) motivation and caregivers' importance; and (3) barriers to attendance at outpatient CR; and 2 additional themes among clinicians: (4) gaps in care transitions; and (5) educational needs. Questionnaire results demonstrated significantly increased knowledge posttraining compared with pretraining among home care clinicians (pretest mean = 12.81; posttest mean = 14.63, P < .001). There was no significant difference between scores for nurses and rehabilitation therapists.

CONCLUSIONS

Home care clinicians respond well to an adapted CR training to improve care for homebound patients with cardiovascular disease. Clinicians who participated in the training demonstrated an increase in their knowledge and skills of the core competencies for CR.

Lifestyle risk reduction interventions in atrial fibrillation: a systematic review

BACKGROUND

The burden of atrial fibrillation (AF) is escalating even though it is potentially modifiable. Affected persons, at high risk of stroke and death, are typically not targeted for risk reduction. We aimed to determine if risk-factor interventions can improve physical functioning, health-related quality of life (HRQoL) and cardiovascular risk in AF.

METHODS

We conducted a systematic review of clinical trials evaluating lifestyle and biomedical risk reduction interventions in AF patients. Trials were identified by searching electronic databases, reference lists and grey literature. Trials were included if conducted by a health professional, and reported changes in multiple risk factor levels or HRQoL.

RESULTS

Five trials, solely exercise based, were identified (166 participants): two randomised controlled trials, one quasi-experimental and two pre-post designs. Exercise capacity improved after 2-12 months in the intervention group in all trials. This was assessed by maximal oxygen uptake (two trials, 2.5-5.4 ml/kg/min (17-32%) improvement, p < 0.02); six-minute walking distance (one trial, 114 m (27%) improvement, p < 0.001); cumulated work (one trial, 564 W/min (37%) improvement, p < 0.001) and incremental exercise testing (one trial, 11 m/min (10%) improvement, p = 0.05). Three trials evaluated heart rate (HR), demonstrating HR reduction at rest (7-13 bpm, p < 0.05) and during exercise (9 bpm, p < 0.05). Two trials measured HRQoL, both reporting significant improvements in SF-36 physical summary scores.

CONCLUSIONS

Literature suggests risk reduction interventions for AF can improve exercise levels, HRQoL and reduce HR, but the evidence base is small, methodologically compromised and focused on physical functioning. High-quality research in this area is required in order to help the multitudes of people living with AF.

Renal sympathetic denervation provides ventricular rate control but does not prevent atrial electrical remodeling during atrial fibrillation

Renal denervation (RDN) reduces renal efferent and afferent sympathetic activity thereby lowering blood pressure in resistant hypertension. The effect of modulation of the autonomic nervous system by RDN on atrial electrophysiology and ventricular rate control during atrial fibrillation (AF) is unknown. Here we report a reduction of ventricular heart rate in a patient with permanent AF undergoing RDN. Subsequently, we investigated the effect of RDN on AF-induced shortening of atrial effective refractory period, AF inducibility, and ventricular rate control during AF maintained by rapid atrial pacing in 12 pigs undergoing RDN (n=7) or sham procedure (n=5). During sinus rhythm, RDN reduced heart rate (RR-interval, 708±12 versus 577±19 ms; P=0.0021) and increased atrioventricular node conduction time (PQ-interval, 112±12 versus 88±9 ms; P=0.0001). Atrial tachypacing for 30 minutes increased AF inducibility and decreased AF cycle length. This was not influenced by RDN. RDN reduced ventricular rate during AF episodes by ≈24% (119±9 versus 158±19 bpm; P=0.0001). AF episodes were shorter after RDN compared with sham (12±3 versus 34±4 s; P=0.0091), but atrial effective refractory period was not modified by RDN. RDN reduced heart rate and reduced atrioventricular node conduction time during sinus rhythm and provided rate control during AF. AF-induced atrial electrical remodeling, AF inducibility, and AF cycle length were not modified, but duration of AF episodes was shorter after RDN. Modulation of the autonomic nervous system by RDN might provide rate control and reduce susceptibility to AF. Whether RDN may provide rate control in a larger number of patients with AF deserves further clinical studies.

Transforming growth factor beta 1 (TGF-beta 1) in atrial fibrillation and acute congestive heart failure

PURPOSE

Atrial fibrillation (AF) and acute congestive heart failure (aCHF) are characterized by an adverse cardiac remodeling. Arrhythmogenic or structural remodeling can be caused by interstitial fibrosis. Transforming growth factor beta 1 (TGF-beta 1) represents a central regulator of cardiac fibrosis. This study investigates serum levels of TGF-beta 1 in patients with AF and aCHF.

METHODS

401 patients presenting with symptoms of dyspnea or peripheral edema were prospectively enrolled. Blood samples for measurement of TGF-beta 1 (R&D Systems, Inc.) and amino-terminal pro-brain natriuretic peptide (NT-proBNP) (DadeBehring ltd.) were collected after the initial clinical evaluation.

RESULTS

Median TGF-beta 1 levels were lower in patients with AF (21.0 ng/ml, interquartile range (IR) 15.4-27.6 ng/ml, n = 107) compared to those without (25.0 ng/ml, IR 18.5-31.6 ng/ml, n = 294) (p = 0.009). Patients with aCHF had lower TGF-beta 1 levels (median 22.0 ng/ml, IR 15.6-27.1 ng/ml, n = 122) than those without (median 24.9 ng/ml, IR 18.1-31.9 ng/ml, n = 279) (p = 0.0005). In logistic regression models TGF-beta 1 was still associated with AF (odds ratio (OR) 3.00, 95% CI 1.37-6.61, p = 0.0001) and aCHF (OR 3.98, 95% CI 1.55-10.19, p = 0.004). TGF-beta 1 inversely correlated with left atrial diameter (r = -0.30, p = 0.007) and NT-proBNP (r = -0.14, p = 0.007).

CONCLUSIONS

Low serum levels of TGF-beta 1 are associated with AF and aCHF. This decrease may result from a higher consumption of TGF-beta 1 within the impaired myocardium or antifibrotic functions of natriuretic peptides.