Prevalence of paroxysmal atrial fibrillation in a population assessed by continuous 24-hour monitoring.

INTRODUCTION

Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice and a major cause of morbidity, due to the associated risk of stroke. However, since it is often paroxysmal, it is commonly underdiagnosed and undertreated.

OBJECTIVES

The primary objective of this prospective study was to determine the prevalence of paroxysmal atrial fibrillation (PAF) in patients aged 40 and above in a population who underwent continuous 24-hour electrocardiographic monitoring. The secondary objectives were to determine the overall prevalence of AF/atrial flutter (AFL) regardless of the type and to compare the population with AF with the general population and patients with PAF with patients with AF.

RESULTS

A total of 4843 consecutive patients were analyzed, 58% women, 26.2% aged 70-79 years (n=1269), 25.9% (n=1252) aged 60-69 years, and 19.0% (n=923) aged 50-59 years; the others were aged either >80 years (n=712, 14.7%) or <50 years (n=686, 14.2%). At least one episode of PAF was detected in 123 patients, a prevalence of 2.5% (95% CI: 2.1-3.0). The prevalence of persistent AF throughout the monitoring period was 9.4% (95% CI: 8.6-10.2) (n=454). Additionally, 39 cases of typical AFL were detected, but in 23 of them (sustained or paroxysmal) this appeared isolated, a prevalence of 0.8% (95% CI: 0.6-1.1). The overall prevalence of AF/AFL was thus 12.4%. The presence of some type of AF/AFL was significantly correlated with male gender (p<0.001), age (especially in the 70-79 and >80 age-groups) (p<0.001) and hypertension (p<0.001). This group had a significantly higher prevalence of previous stroke (56 patients [9.3%], p=0.001) and acute myocardial infarction (5.3%, p<0.001). Comparing the population with PAF and/or paroxysmal AFL (PAF/PAFL) to those with persistent AF (during 24-hour monitoring), significant differences were found: a higher prevalence of PAF/PAFL in younger individuals (40-49, 50-59 and 60-69 age-groups) and lower in older individuals (70-79 and >80 age-groups) (p<0.001), higher prevalence of history of stroke (p=0.024), and lower levels of hypertension (p<0.001). Only 12.8% of patients with PAF were taking anticoagulant drugs.

CONCLUSIONS

The prevalence of PAF found in a population referred for continuous 24-hour electrocardiographic monitoring for diverse reasons was 2.5% and the overall AF/AFL prevalence was 12.4%. PAF was more prevalent in younger patients. Patients with PAF showed a significantly lower prevalence of hypertension and significantly higher rates of stroke. Systematically detecting patients with PAF is a major public health concern, since early diagnosis is essential to identify candidates for oral anticoagulation and catheter ablation, which is frequently curative when applied at this stage.