Elsevier

Heart Rhythm

Volume 11, Issue 6, June 2014, Pages 939-945
Heart Rhythm

Asymptomatic persistent atrial fibrillation and outcome: Results of the RACE study

https://doi.org/10.1016/j.hrthm.2014.03.016Get rights and content

Background

Symptoms are a major driver for patients with atrial fibrillation (AF) to seek medical attention and are important to titrate AF therapies. However, a large proportion of patients with AF are asymptomatic.

Objective

To investigate the clinical profile and prognosis of patients with asymptomatic recurrent persistent AF in the RAte Control versus Electrical cardioversion for persistent atrial fibrillation study.

Methods

Patients with asymptomatic AF (n = 157 [30%]) were compared with patients with symptomatic AF (n = 365 [70%]). The primary end point was a composite of cardiovascular morbidity and mortality.

Results

Patients with asymptomatic AF were younger and more often men than were patients with symptomatic AF. Cardiac diseases were less common. Quality of life (the Medical Outcomes Study Short-form health survey questionnaire) was better in patients with asymptomatic AF and comparable to healthy controls. At baseline and during follow-up, there were no differences in rate control, antiarrhythmic, or anticoagulant drugs; cardioversions; and time in sinus rhythm. After a follow-up of 2.3 ± 0.6 years, the primary end point occurred in 21 (13%) patients with asymptomatic AF and 83 (23%) patients with symptomatic AF. After adjusting for relevant covariates, asymptomatic AF was associated with a lower risk of the primary end point (hazard ratio 0.51; 95% confidence interval 0.29–0.92; P = .024). This difference was driven by significantly less heart failure hospitalizations (0 vs 21 [6%]) and severe effects of antiarrhythmic drugs or digoxin (1 [0.6%] vs 13 [4%]). Importantly, no difference in the occurrence of thromboembolic complications was observed.

Conclusion

Patients with asymptomatic AF were more often men and had less cardiac disease. During follow-up, in patients with asymptomatic AF, heart failure hospitalizations and severe adverse effects of antiarrhythmic and rate control drugs occurred significantly less frequently.

Introduction

Atrial fibrillation (AF) may be accompanied by symptoms, impaired quality of life, and an increased risk of stroke, dementia, heart failure, and death.1 Although most patients with AF have symptoms, approximately 15%–30% of the patients diagnosed with clinical AF appear asymptomatic.2, 3 In patients with pacemaker and ICD and without a clinical diagnosis of AF, but at risk for AF, the incidence of (short) episodes of high atrial rates and silent AF is even higher.4, 5 At present, it remains uncertain why some patients with AF are asymptomatic and others are symptomatic and whether the presence of symptoms is associated with prognosis. It has been observed that in older patients, symptoms may decrease or disappear with longer durations of the arrhythmia.2, 3, 6 Somatic, psychological factors and the presence of other cardiovascular conditions that may present with similar symptoms or aggravate symptoms are likely to contribute to the complex relation between symptoms and AF.3, 7 The latest guidelines of the European Society of Cardiology identifies “asymptomatic AF” as a specific clinical form and recommend classification using the European Heart Rhythm Association score of AF-related symptoms.1, 8 Classification of AF according to symptom burden is important since large randomized trials have demonstrated that the outcome of rate control vs rhythm control therapies is similar9, 10 and choice for a rate or rhythm control treatment strategy is largely driven by the degree of AF-related symptoms. Also, symptom burden is important to guide therapy and evaluate success of especially rhythm control strategies.

At present, it is uncertain whether simple awareness of symptoms can be used as a prognostic marker for specific cardiovascular outcomes in patients known and treated for AF. We sought to investigate potential differences in the clinical profile and prognosis of asymptomatic and symptomatic patients with recurrent persistent AF, as included in the RAte Control versus Electrical cardioversion for persistent atrial fibrillation (RACE) study.10

Section snippets

Study design

Study design, patient characteristics, and results of the RACE study have been published previously.10 In short, 522 patients (157 [30%] patients with asymptomatic AF) with recurrent persistent AF were included and randomized to rate or rhythm control. Patients were followed for at least 2 years with a maximum of 3 years. The follow-up scheme is described in Online Supplemental Methods.

Administration of a β-blocker, a nondihydropyridine calcium-channel blocker, or digitalis, alone or in

Patient characteristics

At randomization, 157 of 522 (30%) patients had asymptomatic persistent AF. The other 365 (70%) patients had at least 1 AF-related symptom: palpitations (n = 143 [39%]), dyspnea (n = 185 [51%]), fatigue (n = 207 [57%]), angina pectoris (n = 34 [9%]), presyncope (n = 13 [4%]), or other complaints (n = 73 [20%]). Patients with asymptomatic AF were younger and more often men (Table 1). Concomitant cardiovascular conditions as coronary artery disease and cardiomyopathy were less common in patients

Discussion

In the present post hoc analysis of the RACE study,10 we observed that patients with asymptomatic persistent AF had less cardiovascular diseases and the composite primary end point, mainly driven by heart failure hospitalizations and severe adverse effects of antiarrhythmic and rate control drugs, occurred less frequently than in patients with symptomatic AF. In multivariate analysis after adjusting for differences in clinical characteristics, medication use, and echocardiographic measurements,

Conclusion

Patients with asymptomatic persistent AF had less cardiac disease, and when treated, they had less heart failure hospitalizations and severe adverse effects of antiarrhythmic drugs and rate control drugs as compared with those with symptomatic AF. Future studies are warranted to further clarify the mechanisms underlying AF symptoms and prognosis.

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  • Cited by (0)

    The first 2 authors contributed equally to this work.

    This work was supported by grants from the Center of Health Care Insurance (OG96-047) and the Interuniversity Cardiology Institute, The Netherlands, and by an unrestricted grant from 3M Pharma, The Netherlands.

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