Atrial Fibrilation Opportunistic Screening and Stroke Incidence (AFOSS): Searching the Unknown Atrial Fibrillation.

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice, and is increasing in both incidence and prevalence. Almost two hundred thousand Catalonian people over 60 year-old currently have AF, and estimates project that between 250.000 and 300.000 will be affected by 2050. Perhaps the most important consequence of AF is the risk of embolic stroke.

It has been estimated that around one in five strokes are attributed to AF overall, and one in three strokes in people over the age of 80 are attributed to AF. AF-related strokes are associated with significant morbidity, mortality and healthcare costs, yet they are highly preventable. Unfortunately, AF is often undiagnosed or untreated when stroke occurs.

In addition, the absolute prevalence of undiagnosed atrial fibrillation in individuals over 60 years of age is 2.2%, equivalent to 20.1% of the overall prevalence of AF. This is higher than in the reports of other studies, which range from 0.49% to 1.7% when diagnosed by means of standard ECG, but lower than the AF incidence (30%) detected by continuous monitoring in patients with risk factors for stroke. The prevalence of AF in the community is probably underestimated, as a consequence of the failure to detect and diagnose it and may be responsible for an additional subset of the 25-40% of strokes of unknown cause. It has been suggested that asymptomatic AF represents a third of the total AF population, a result confirmed in pacemaker studies. Around thirty eight thousand Catalonian people over 60 year-old currently could suffer unknown AF, and consequently non-treated, and estimates project that between 1,350-2,475 stroke/year could be related to this untreated condition.

While the data confirm the evident age-related increase in the prevalence of persistent AF and demonstrate that hypertension is the most frequently associated cardiovascular risk factor together with the presence of cardiovascular disease there is not sufficient evidence regarding the procedures that may be most effective for achieving an early diagnosis of AF and reducing the associated risks. A significant proportion of people with AF are diag¬nosed by chance during health assessments carried out for other reasons, or due to having a stroke. There may be multiple reasons for under-diagnosis, including the fact that AF can be asymptomatic and a lack of awareness about the condition and its symptoms. There is considerable interest in developing AF screening programs

Opportunistic screening, where patients are checked for AF when they visit doctors for other reasons, is widely supported as a means to achieve higher rates of detec¬tion to enable early intervention. Screening for AF anyone >65 years or at high risk of stroke has been recommended by Mention of European Society of Cardiology (ESC), Stroke Alliance for Europe (SAFE), European Heart Rhythm Association (EHRA), Royal College of Physicians of Edinburg (RCPE), World Healthcare Forum (WHF), European Primary Care Cardiovascular Society (EPCCS), Health Information and Quality Authority (HIQA), and AF-SCREEN. Currently, routine mass screenings are not carried out in any countries at a national level. Opportunistic screening was tested against routine screening by the SAFE study, which found that opportunistic screening improved on routine practice and out¬reach campaign in Spain[23] was found to have had little effect on diagnosis of previously undetected AF and it was concluded that opportunistic screening is thus a better strategy for early detection.