Prevalence of atrial fibrillation in the general population and in high-risk groups
Davis RC., Hobbs FDR., Lancashire RJ., McLeod S., Wosornu D., Kenkre JE., Davies MK.
Atrial fibrillation (AF) is the commonest cardiac arrhythmia and is associated with high risk of embolic stroke, which can be reduced by anticoagulation. To have an impact on the population as a whole, patients must first be identified, and screening would be most cost-effective if targeted on patients at high risk of the condition. We have investigated the prevalence of AF in different age groups in the general population, and in those in high risk groups. Methods: We have analysed the prevalence of AF and associated echocardiographic risk actors in patients in the following groups: Random population sample, aged 45+; existing clinical diagnosis of heart failure (made by GP); previous MI; hypertension; angina; and diabetes. Patients were assessed clinically and with ECG and echocardiography, as part of a large heart failure epidemiology study. Results: The table details the prevalence of AF in the patient groups. Other associated risk factors for embolic stroke (mitral valve disease, left atrial enlargement or impaired LV function) are also listed, and the proportion anticoagulated at the time of screening. AF Abnormal echo in pts with AF On warfarin Population aged 45+ 43/2552 (1.7%) 29/43 (67%) 9/43 (21%) of which: 45-54 1/858 (0.1%) 1/1 (100%) 1/1 (100%) 55-64 7/785 (0.9%) 2/7 (29%) 1/7 (14%) 65-74 9/615 (1.5%) 6/9 (67%) 4/9 (44%) 75+ 26/294 (8.8%) 20/26 (77%) 3/26 (12%) Clinical heart failure 69/279 (24.7%) 61/69 (88%) 24/69 (35%) Previous MI 8/117 (6.8%) 6/8 (75%) 3/8 (37%) Hypertension 5/192 (2.6%) 2/5 (40%) 1/5 (20%) Angina 4/120 (3.3%) 3/4 (75%) 2/4 (50%) Diabetes 3/58 (5.2%) 3/3 (100%) 2/3 (67%) Conclusions: AF prevalence in the population sample was 1.7%, and in the high-risk groups overall was 11.6%; these patients had other embolic risk factors more frequently also. Targeting screening on such patients would identify many patients at high stroke risk.