Prevalence and risk factors of atrial fibrillation in preterminal inpatients aged 60 years and over

Background Atrial fibrillation is a common arrhythmia and a major risk factor for ischaemic stroke.We investigated the prevalence of atrial fibrillation and its relation to age,gender and underlying heart disease in patients aged 60 years and over who died during hospitalization. Methods Between 1955 and 2005,1519 autopsies of in-hospital deaths in Beijing Hospital were performed.Among them,540 cases met criteria of age≥60 years and full clinical history including electrocardiogram,echocardiogram, myocardial perfusion images and detailed cardiac pathology records from autopsy. Results Atrial fibrillation occurred in 193 of 540 patients and prevalence increased with age(10.5%in patients younger than 60 years,39.6%(80-89 years)and 54.8%(≥90 years))being higher in patients with underlying heart disease than without heart disease(P<0.0001).Coronary artery disease(CAD),congestive heart failure,cardiac valve dysfunction and chronic renal failure were associated with a higher prevalence of atrial fibrillation(P<0.001).CAD with anterior myocardial infarction or left anterior descending artery disease was also associated with an increased prevalence of atrial fibrillation(P<0.05).Following autopsy,clinical misdiagnosis of CAD increased with age and missed clinical diagnosis of CAD decreased with age.Multivariate Logistic regression analysis revealed independent predictors of atrial fibrillation:age(OR=1.335,95%CI:1.114-1.600,P<0.0001),underlying heart disease(OR=2.019,95%CI: 1.244-3.278,P<0.005),chronic heart failure(OR=1.873,95%CI:1.272-2.757,P<0.005),mitral regurgitation (OR=2.163,95%CI:1.093-4.278,P<0.05)and mitral stenosis(OR=33.575,95%CI:2.852-395.357,P<0.05). Conclusions A high prevalence of atrial fibrillation was found in Chinese patients≥60 years who died in hospital, especially when associated with underlying heart disease.The independent risk factors of atrial fibrillation were age, underlying heart disease,congestive heart failure and mitral valve dysfunction.High clinical misdiagnosis and missed diagnosis of CAD were associated with age.