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Global variation in the etiology and management of atrial fibrillation: results from a global atrial fibrillation registry

Atrial Fibrillation

Jeff Healey(Canada)
Presentation webcast
Presentation slides

List of Authors:
J.S. Healey, J. Oldgren, A. Parekh, P. Commerford, A. Avezum, P. Pais, J. Zhu, P. Jansky, A. Sigamani, C.A. Morillo, L. Liu, A. Damasceno, A. Grinvalds, P. Reilly, M. Ezekowitz, L. Wallentin, S.J. Connolly and S. Yusuf, on behalf of the RE-LY Atrial Fibrillation Registry Investigators


Background: Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide; however, much of our understanding of AF is based on studies conducted in North America and Europe. Large global variation in the causes and management of AF likely exists; however, this has never been accurately measured in a large, truly global primary care registry of AF, which includes low-income countries.

Methods: The AF registry enrolled patients who presented to an emergency department between January 2008 and April 2011 with AF or atrial flutter, either as a primary or secondary diagnosis. Site selection was purposeful to include academic and community settings, rural and urban areas. Patient information was obtained from their clinical record. The registry included 163 sites from 47 countries, representing 9 major geographic regions. Patient characteristics were compared against the North American patients and the prevalence of risk factors was adjusted for age.

Results: A total of 15,174 patients were enrolled: 44% with AF as their primary diagnosis and 30% with their first documented episode of AF. Atrial flutter was present in 2%. The number of sites and patients from each major region were: North America (18; 1802), South America (23; 1127), Western Europe (19; 1975), Eastern Europe (22; 2536), Middle-East (8; 896), Africa (20; 1,089), India (22; 2520), China (20; 1951) and Asia (11; 1278). The median age of patients in North America was 72 years (IQR: 62-80). By comparison, patients in Africa, the Middle East and India were 10-12 years younger (Table 1).

Hypertension was the most prevalent predisposing condition for AF. Compared to North America (70.4%), the prevalence of hypertension was higher in Eastern Europe and South America, but lower elsewhere (Table 1). Patients in South America, Eastern Europe and Africa were more likely to have hypertension complicated by left ventricular hypertrophy, while this was less frequent among patients in Western Europe, the Middle East, India and China (Table 1). In North America, the average systolic blood pressure among patients with a history of hypertension was 136.7 mmHg, with better control in India and poorer control in Eastern Europe, Africa and China (Table 1).

Heart failure was the second most prevalent predisposing condition; present in 27.6% of North Americans. Its prevalence ranged from 17.7% in India to 64.6% in Africa (Table 1). The proportion of patients with heart failure associated with valvular heart disease was highest in India and Africa and lowest in Western and Eastern Europe (Table 1). Prior myocardial infarction was present in 21.7% of North American patients with heart failure, but in a much smaller proportion of patients in Africa, India, China and Asia (Table 1). Rheumatic heart disease was present in only 2.2% of North American patients with AF and ranged from 2.0% among patients in Western Europe to over 31% of patients in India (Table 1). A history of stroke was present in 15.4% of North American patients and ranged from 7.3% in India to 21.7% in Asia (Table 1). Among North American patients with a prior history of AF, the use of oral anticoagulation (OAC) among patients with a CHADS2 score of ≥ 2 was 65.1%, which was higher than in all other regions except Western Europe (Table 1). OAC was greater among patients with rheumatic heart disease, with similar regional trends (Table 1). For patients treated with OAC, the proportion of INR values between 2.0 and 3.0 was 54% in North America. Patients in Western (67%) and Eastern Europe (59%) had a greater proportion of in-range INR values, while those in India (34%), China (36%), Asia (38%) and Africa (40%) had a lower proportion (Table 1).

Conclusions: The presentation, etiology and treatment of AF vary greatly between geographic regions. Although hypertension is the most common predisposing condition for AF in all regions, rheumatic heart disease remains an important cause in India, Africa, the Middle East and China. Worldwide, appropriate use of OAC is low, with wide variation between regions. INR control is poor worldwide, with the exception of Western Europe.

Age (median, IQR) 72
Hypertension 70.4% 77.3%* 59.8%* 80.5%* 56.1%* 54.8%* 41.7%* 55.7%* 63.9%*
> with LVH 21.0% 30.6%* 11.7%* 45.8%* 11.2%* 38.5%* 6.6%* 11.2%* 20.5%
> Systolic BP(mean) 136.7 136.2 138.5 140.5* 138.2 142.2* 133.3* 140.6* 136.7
Heart Failure 27.6% 35.1%* 21.2%* 58.3%* 28.3% 64.6% 17.7%* 36.0%* 26.1%
> with Valvular disease 30.5% 29.3% 20.5%* 14.1%* 36.6% 39.2%* 50.3%* 28.8% 30.4%
> with Prior MI 21.7% 17.7% 27.9% 22.4% 21.7% 5.1%* 9.8%* 9.1%* 11.3%*
> with Hypertension 35.7% 27.9% 32.5% 51.4%* 31.5% 38.6% 23.2%* 36.8% 40.3%
Rheumatic Heart Disease 2.2% 6.7%* 2.0% 3.7%* 15.5%* 21.7%* 31.1%* 15.3%* 3.7%
Prior stroke 15.4% 14.5% 11.9%* 12.5% 11.4% 14.1% 7.3%* 18.8% 21.7%*
OAC use (CHADS2 ≥ 2) 65.1% 44.8%* 63.5% 38.7%* 55.8%* 36.9%* 39.9%* 10.5 %* 43.6%*
OAC use (Rheumatic) 73.9% 84.7% 92.9% 71.9% 85.6% 47.5% 52.5% 43.3 % 82.4%
Proportion of INR values 53.5% 43.5%* 66.9%* 59.1% 46.8% 39.5%* 33.9%* 36.1%* 38.4%*

* p < 0.005 vs. North America; among patients with a prior history of AF




Clinical Registry Highlight I - Risk and treatment reality

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.