human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVES To evaluate the cost-effectiveness of a  national atrial fibrillation screening program in Irel and involving annual opportunistic pulse palpation of all those older than 65 years during general practitioner consultations , with an electrocardiogram being performed if an irregular pulse is detected . METHODS A probabilistic Markov model was used to simulate costs and clinical outcomes in a hypothetical cohort of men and women with and without screening over the course of 25 years , using a societal perspective . RESULTS Screening was associated with an incremental cost-effectiveness ratio of € 23,004/ quality -adjusted life-year compared with routine care . Nevertheless , if the relative risk of stroke and systematic embolism in screen-detected patients is more than 12 % lower than that in patients with atrial fibrillation identified through routine practice , then screening would not be considered cost-effective at a willingness-to-pay threshold of € 45,000/ quality -adjusted life-year . An analysis comparing alternative combinations of start age and screening interval found that less frequent screening with a later start age may be more cost-effective than an annual screening from age 65 years . CONCLUSIONS Annual opportunistic screening of men and women aged 65 years and older in primary care in Irel and is likely to be cost-effective using conventional willingness-to-pay thresholds , assuming that those detected through screening have a comparable stroke risk profile as those detected through routine practice . Raising the start age of screening or increasing the screening interval may improve the cost-effectiveness of a prospect i ve screening program Objectives To assess whether screening improves the detection of atrial fibrillation  ( cluster r and omisation ) and to compare systematic and opportunistic screening . Design Multicentred cluster r and omised controlled trial , with subsidiary trial embedded within the intervention arm . Setting 50 primary care centres in Engl and , with further individual r and omisation of patients in the intervention practice s. Participants 14 802 patients aged 65 or over in 25 intervention and 25 control practice s. Interventions Patients in intervention practice s were r and omly allocated to systematic screening ( invitation for electrocardiography ) or opportunistic screening ( pulse taking and invitation for electrocardiography if the pulse was irregular ) . Screening took place over 12 months in each practice from October 2001 to February 2003 . No active screening took place in control practice s. Main outcome measure Newly identified atrial fibrillation . Results The detection rate of new cases of atrial fibrillation was 1.63 % a year in the intervention practice s and 1.04 % in control practice s ( difference 0.59 % , 95 % confidence interval 0.20 % to 0.98 % ) . Systematic and opportunistic screening detected similar numbers of new cases ( 1.62 % v 1.64 % , difference 0.02 % , −0.5 % to 0.5 % ) . Conclusion Active screening for atrial fibrillation detects additional cases over current practice . The preferred method of screening in patients aged 65 or over in primary care is opportunistic pulse taking with follow-up electrocardiography . Trial registration Current Controlled Trials IS RCT N19633732 INTRODUCTION AND OBJECTIVES Atrial fibrillation is associated with substantial morbidity and mortality and both its incidence and prevalence are high . Nevertheless , comprehensive data on this condition in Spain are lacking . The aim of this study was to estimate the prevalence of atrial fibrillation in Spain . METHODS A cross-sectional study was conducted in the general Spanish population older than 40 years . Two-stage r and om sampling was used , in which first-stage units were primary care physicians r and omly selected in every Spanish province and second-stage units were 20 r and omly selected persons drawn from each participating physician 's assigned population . The reported prevalence was st and ardized for the age and sex distribution of the Spanish population . The  electrocardiogram recordings  were read central ly . RESULTS Overall , 8343 individuals were evaluated . The mean age was 59.2 years ( 95 % confidence interval , 58.6 - 59.8 years ) , and 52.4 % of the participants were female . The overall age-adjusted prevalence of atrial fibrillation was 4.4 % ( 95 % confidence interval , 3.8 - 5.1 ) . Prevalence was similar in both sexes , men 4.4 % ( 3.6 - 5.2 ) and women 4.5 % ( 3.6 - 5.3 ) , rising with increasing age older than 60 years . In patients older than 80 years , the prevalence was 17.7 % ( 14.1 - 21.3 ) . In 10 % of patients an unknown atrial fibrillation was diagnosed . CONCLUSIONS The prevalence of atrial fibrillation in the general Spanish population older than 40 years is high , at 4.4 % . The prevalence is similar in both sexes and rises steeply above 60 years of age . It is estimated that there are over 1 million patients with atrial fibrillation in the Spanish population , of whom over 90,000 are undiagnosed BACKGROUND One quarter of strokes are of unknown cause , and sub clinical atrial fibrillation may be a common etiologic factor . Pacemakers can detect sub clinical episodes of rapid atrial rate , which correlate with electrocardiographically documented atrial fibrillation . We evaluated whether sub clinical episodes of rapid atrial rate detected by implanted devices were associated with an increased risk of ischemic stroke in patients who did not have other evidence of atrial fibrillation . METHODS We enrolled 2580 patients , 65 years of age or older , with hypertension and no history of atrial fibrillation , in whom a pacemaker or defibrillator had recently been implanted . We monitored the patients for 3 months to detect sub clinical atrial tachyarrhythmias ( episodes of atrial rate > 190 beats per minute for more than 6 minutes ) and followed them for a mean of 2.5 years for the primary outcome of ischemic stroke or systemic embolism .  Patients with pacemakers  were r and omly assigned to receive or not to receive continuous atrial overdrive pacing . RESULTS By 3 months , sub clinical atrial tachyarrhythmias detected by implanted devices had occurred in 261 patients ( 10.1 % ) . Sub clinical atrial tachyarrhythmias were associated with an increased risk of clinical atrial fibrillation ( hazard ratio , 5.56 ; 95 % confidence interval [ CI ] , 3.78 to 8.17 ; P<0.001 ) and of ischemic stroke or systemic embolism ( hazard ratio , 2.49 ; 95 % CI , 1.28 to 4.85 ; P=0.007 ) . Of 51 patients who had a primary outcome event , 11 had had sub clinical atrial tachyarrhythmias detected by 3 months , and none had had clinical atrial fibrillation by 3 months . The population attributable risk of stroke or systemic embolism associated with sub clinical atrial tachyarrhythmias was 13 % . Sub clinical atrial tachyarrhythmias remained predictive of the primary outcome after adjustment for predictors of stroke ( hazard ratio , 2.50 ; 95 % CI , 1.28 to 4.89 ; P=0.008 ) . Continuous atrial overdrive pacing did not prevent atrial fibrillation . CONCLUSIONS Sub clinical atrial tachyarrhythmias , without clinical atrial fibrillation , occurred frequently in patients with pacemakers and were associated with a significantly increased risk of ischemic stroke or systemic embolism . ( Funded by St. Jude Medical ; ASSERT Clinical Trials.gov number , NCT00256152 . ) Background There is limited information on prevalent and incident atrial fibrillation in Chinese . We aim ed to investigate the prevalence , incidence , management and risks of atrial fibrillation in an elderly Chinese population . Methods In a population —based prospect i ve study in elderly ( ≥60 years ) Chinese , we performed cardiovascular health examinations including a 12-lead electrocardiogram at baseline in 3,922 participants  and biennially during follow-up in 2,017 participants . We collected information on vital status during the whole follow-up period . Results The baseline prevalence of atrial fibrillation was 2.0 % ( n = 34 ) in 1718 men and 1.6 % ( n = 36 ) in 2204 women . During a median 3.8 years of follow-up , the incidence rate of atrial fibrillation ( n = 34 ) was 4.9 per 1000 person-years ( 95 % confidence interval [ CI ] , 3.4–6.9 ) . In univariate analysis , both the prevalence and incidence of atrial fibrillation were higher with age advancing ( P < 0.0001 ) and in the presence of coronary heart disease ( P ≤ 0.02 ) . Of the 104 prevalent and incident cases of atrial fibrillation , only 1 ( 1.0 % ) received anticoagulant therapy ( warfarin ) . These patients with atrial fibrillation , compared with those with sinus rhythm , had significantly higher risks of all-cause ( n = 261 , hazard ratio [ HR ] 1.87 , 95 % CI , 1.09–3.20 , P = 0.02 ) , cardiovascular ( n = 136 , HR 3.78 , 95 % CI 2.17–6.58 , P < 0.0001 ) and stroke mortality ( n = 44 , HR 6.31 , 95 % CI 2.81–14.19 , P = 0.0003 ) . Conclusions Atrial fibrillation was relatively frequent in elderly Chinese , poorly managed and associated with higher risks of mortality OBJECTIVE / BACKGROUND This pilot study of a large population based r and omised screening trial investigated feasibility , acceptability , and relevance ( prevalence of clinical and sub clinical cardiovascular disease [ CVD ] and proportion receiving insufficient prevention ) of a multifaceted screening for CVD . METHODS In total , 2060 r and omly selected Danish men and women aged 65 - 74 years were offered ( i ) low dose non-contrast computed tomography to detect coronary artery calcification ( CAC ) and aortic/iliac aneurysms ; ( ii ) detection of atrial fibrillation ( AF ) ; ( iii ) brachial and ankle blood pressure measurements ; and ( iv ) blood levels of cholesterol and hemoglobin A1c . Web based self booking and data management was used to reduce the administrative burden . RESULTS Attendance rates were 64.9 % ( n = 678 ) and 63.0 % ( n = 640 ) for men and women , respectively . In total , 39.7 % received a recommendation for medical preventive actions . Prevalence of aneurysms was 12.4 % ( 95 % confidence interval [ CI ] 9.9 - 14.9 ) in men and 1.1 % ( 95 % CI 0.3 - 1.9 ) in women , respectively ( p < .001 ) . A CAC score > 400 was found in 37.8 % of men and 11.3 % of women ( p < .001 ) , along with a significant increase in median CAC score with age ( p = .03 ) . Peripheral arterial disease was more prevalent in men ( 18.8 % , 95 % CI 15.8 - 21.8 ) than in women ( 11.2 % , 95 % CI 8.7 - 13.6 ) . No significant differences between the sexes were found with regard to newly discovered AF ( men 1.3 % , women 0.5 % ) , potential hypertension ( men 9.7 % , women 11.5 % ) , hypercholesterolemia ( men 0.9 % , women 1.1 % ) or diabetes mellitus ( men 2.1 % , women 1.3 % ) . CONCLUSION Owing to the higher prevalence of severe conditions , such as aneurysms and CAC ≥ 400 , screening for CVD seemed more prudent in men than women . The attendance rates were acceptable compared with other screening programs and the logistical structure of the screening program proved successful Background : Asymptomatic atrial fibrillation ( AF ) is increasingly common in the aging population and implicated in many ischemic strokes . Earlier identification of AF with appropriate anticoagulation may decrease stroke morbidity and mortality . Methods : We conducted a r and omized controlled trial of AF screening using an AliveCor Kardia monitor attached to a WiFi-enabled iPod to obtain ECGs ( iECGs ) in ambulatory patients . Patients ≥65 years of age with a CHADS-VASc score ≥2 free from AF were r and omized to the iECG arm or routine care ( RC ) . iECG participants acquired iECGs twice weekly over 12 months ( plus additional iECGs if symptomatic ) onto a secure study server with overread by an automated AF detection algorithm and by a cardiac physiologist and /or consultant cardiologist . Time to diagnosis of AF was the primary outcome measure . The overall cost of the devices , ECG interpretation , and patient management were captured and used to generate the cost per AF diagnosis in iECG patients . Clinical events and patient attitudes/experience were also evaluated . Results : We studied 1001 patients ( 5 
    Output:
    
agent
Pooled yield of screening was greater in males across all age strata .
Neither the choice of screening methodology or device , the geographical region , nor the screening setting influenced the detection rate of AF .
The main limitation of this study is there are insufficient data on sociodemographic variables of the population s and possible ascertainment biases to explain the variance in the sample s. CONCLUSIONS People with screen-detected AF are at elevated calculated stroke risk : above age 65 , the majority have a Class-1 OAC recommendation for stroke prevention , and > 70 % have ≥1 additional stroke risk factor other than age/sex .
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVES To evaluate the cost-effectiveness of a  national atrial fibrillation screening program in Irel and involving annual opportunistic pulse palpation of all those older than 65 years during general practitioner consultations , with an electrocardiogram being performed if an irregular pulse is detected . METHODS A probabilistic Markov model was used to simulate costs and clinical outcomes in a hypothetical cohort of men and women with and without screening over the course of 25 years , using a societal perspective . RESULTS Screening was associated with an incremental cost-effectiveness ratio of € 23,004/ quality -adjusted life-year compared with routine care . Nevertheless , if the relative risk of stroke and systematic embolism in screen-detected patients is more than 12 % lower than that in patients with atrial fibrillation identified through routine practice , then screening would not be considered cost-effective at a willingness-to-pay threshold of € 45,000/ quality -adjusted life-year . An analysis comparing alternative combinations of start age and screening interval found that less frequent screening with a later start age may be more cost-effective than an annual screening from age 65 years . CONCLUSIONS Annual opportunistic screening of men and women aged 65 years and older in primary care in Irel and is likely to be cost-effective using conventional willingness-to-pay thresholds , assuming that those detected through screening have a comparable stroke risk profile as those detected through routine practice . Raising the start age of screening or increasing the screening interval may improve the cost-effectiveness of a prospect i ve screening program Objectives To assess whether screening improves the detection of atrial fibrillation  ( cluster r and omisation ) and to compare systematic and opportunistic screening . Design Multicentred cluster r and omised controlled trial , with subsidiary trial embedded within the intervention arm . Setting 50 primary care centres in Engl and , with further individual r and omisation of patients in the intervention practice s. Participants 14 802 patients aged 65 or over in 25 intervention and 25 control practice s. Interventions Patients in intervention practice s were r and omly allocated to systematic screening ( invitation for electrocardiography ) or opportunistic screening ( pulse taking and invitation for electrocardiography if the pulse was irregular ) . Screening took place over 12 months in each practice from October 2001 to February 2003 . No active screening took place in control practice s. Main outcome measure Newly identified atrial fibrillation . Results The detection rate of new cases of atrial fibrillation was 1.63 % a year in the intervention practice s and 1.04 % in control practice s ( difference 0.59 % , 95 % confidence interval 0.20 % to 0.98 % ) . Systematic and opportunistic screening detected similar numbers of new cases ( 1.62 % v 1.64 % , difference 0.02 % , −0.5 % to 0.5 % ) . Conclusion Active screening for atrial fibrillation detects additional cases over current practice . The preferred method of screening in patients aged 65 or over in primary care is opportunistic pulse taking with follow-up electrocardiography . Trial registration Current Controlled Trials IS RCT N19633732 INTRODUCTION AND OBJECTIVES Atrial fibrillation is associated with substantial morbidity and mortality and both its incidence and prevalence are high . Nevertheless , comprehensive data on this condition in Spain are lacking . The aim of this study was to estimate the prevalence of atrial fibrillation in Spain . METHODS A cross-sectional study was conducted in the general Spanish population older than 40 years . Two-stage r and om sampling was used , in which first-stage units were primary care physicians r and omly selected in every Spanish province and second-stage units were 20 r and omly selected persons drawn from each participating physician 's assigned population . The reported prevalence was st and ardized for the age and sex distribution of the Spanish population . The  electrocardiogram recordings  were read central ly . RESULTS Overall , 8343 individuals were evaluated . The mean age was 59.2 years ( 95 % confidence interval , 58.6 - 59.8 years ) , and 52.4 % of the participants were female . The overall age-adjusted prevalence of atrial fibrillation was 4.4 % ( 95 % confidence interval , 3.8 - 5.1 ) . Prevalence was similar in both sexes , men 4.4 % ( 3.6 - 5.2 ) and women 4.5 % ( 3.6 - 5.3 ) , rising with increasing age older than 60 years . In patients older than 80 years , the prevalence was 17.7 % ( 14.1 - 21.3 ) . In 10 % of patients an unknown atrial fibrillation was diagnosed . CONCLUSIONS The prevalence of atrial fibrillation in the general Spanish population older than 40 years is high , at 4.4 % . The prevalence is similar in both sexes and rises steeply above 60 years of age . It is estimated that there are over 1 million patients with atrial fibrillation in the Spanish population , of whom over 90,000 are undiagnosed BACKGROUND One quarter of strokes are of unknown cause , and sub clinical atrial fibrillation may be a common etiologic factor . Pacemakers can detect sub clinical episodes of rapid atrial rate , which correlate with electrocardiographically documented atrial fibrillation . We evaluated whether sub clinical episodes of rapid atrial rate detected by implanted devices were associated with an increased risk of ischemic stroke in patients who did not have other evidence of atrial fibrillation . METHODS We enrolled 2580 patients , 65 years of age or older , with hypertension and no history of atrial fibrillation , in whom a pacemaker or defibrillator had recently been implanted . We monitored the patients for 3 months to detect sub clinical atrial tachyarrhythmias ( episodes of atrial rate > 190 beats per minute for more than 6 minutes ) and followed them for a mean of 2.5 years for the primary outcome of ischemic stroke or systemic embolism .  Patients with pacemakers  were r and omly assigned to receive or not to receive continuous atrial overdrive pacing . RESULTS By 3 months , sub clinical atrial tachyarrhythmias detected by implanted devices had occurred in 261 patients ( 10.1 % ) . Sub clinical atrial tachyarrhythmias were associated with an increased risk of clinical atrial fibrillation ( hazard ratio , 5.56 ; 95 % confidence interval [ CI ] , 3.78 to 8.17 ; P<0.001 ) and of ischemic stroke or systemic embolism ( hazard ratio , 2.49 ; 95 % CI , 1.28 to 4.85 ; P=0.007 ) . Of 51 patients who had a primary outcome event , 11 had had sub clinical atrial tachyarrhythmias detected by 3 months , and none had had clinical atrial fibrillation by 3 months . The population attributable risk of stroke or systemic embolism associated with sub clinical atrial tachyarrhythmias was 13 % . Sub clinical atrial tachyarrhythmias remained predictive of the primary outcome after adjustment for predictors of stroke ( hazard ratio , 2.50 ; 95 % CI , 1.28 to 4.89 ; P=0.008 ) . Continuous atrial overdrive pacing did not prevent atrial fibrillation . CONCLUSIONS Sub clinical atrial tachyarrhythmias , without clinical atrial fibrillation , occurred frequently in patients with pacemakers and were associated with a significantly increased risk of ischemic stroke or systemic embolism . ( Funded by St. Jude Medical ; ASSERT Clinical Trials.gov number , NCT00256152 . ) Background There is limited information on prevalent and incident atrial fibrillation in Chinese . We aim ed to investigate the prevalence , incidence , management and risks of atrial fibrillation in an elderly Chinese population . Methods In a population —based prospect i ve study in elderly ( ≥60 years ) Chinese , we performed cardiovascular health examinations including a 12-lead electrocardiogram at baseline in 3,922 participants  and biennially during follow-up in 2,017 participants . We collected information on vital status during the whole follow-up period . Results The baseline prevalence of atrial fibrillation was 2.0 % ( n = 34 ) in 1718 men and 1.6 % ( n = 36 ) in 2204 women . During a median 3.8 years of follow-up , the incidence rate of atrial fibrillation ( n = 34 ) was 4.9 per 1000 person-years ( 95 % confidence interval [ CI ] , 3.4–6.9 ) . In univariate analysis , both the prevalence and incidence of atrial fibrillation were higher with age advancing ( P < 0.0001 ) and in the presence of coronary heart disease ( P ≤ 0.02 ) . Of the 104 prevalent and incident cases of atrial fibrillation , only 1 ( 1.0 % ) received anticoagulant therapy ( warfarin ) . These patients with atrial fibrillation , compared with those with sinus rhythm , had significantly higher risks of all-cause ( n = 261 , hazard ratio [ HR ] 1.87 , 95 % CI , 1.09–3.20 , P = 0.02 ) , cardiovascular ( n = 136 , HR 3.78 , 95 % CI 2.17–6.58 , P < 0.0001 ) and stroke mortality ( n = 44 , HR 6.31 , 95 % CI 2.81–14.19 , P = 0.0003 ) . Conclusions Atrial fibrillation was relatively frequent in elderly Chinese , poorly managed and associated with higher risks of mortality OBJECTIVE / BACKGROUND This pilot study of a large population based r and omised screening trial investigated feasibility , acceptability , and relevance ( prevalence of clinical and sub clinical cardiovascular disease [ CVD ] and proportion receiving insufficient prevention ) of a multifaceted screening for CVD . METHODS In total , 2060 r and omly selected Danish men and women aged 65 - 74 years were offered ( i ) low dose non-contrast computed tomography to detect coronary artery calcification ( CAC ) and aortic/iliac aneurysms ; ( ii ) detection of atrial fibrillation ( AF ) ; ( iii ) brachial and ankle blood pressure measurements ; and ( iv ) blood levels of cholesterol and hemoglobin A1c . Web based self booking and data management was used to reduce the administrative burden . RESULTS Attendance rates were 64.9 % ( n = 678 ) and 63.0 % ( n = 640 ) for men and women , respectively . In total , 39.7 % received a recommendation for medical preventive actions . Prevalence of aneurysms was 12.4 % ( 95 % confidence interval [ CI ] 9.9 - 14.9 ) in men and 1.1 % ( 95 % CI 0.3 - 1.9 ) in women , respectively ( p < .001 ) . A CAC score > 400 was found in 37.8 % of men and 11.3 % of women ( p < .001 ) , along with a significant increase in median CAC score with age ( p = .03 ) . Peripheral arterial disease was more prevalent in men ( 18.8 % , 95 % CI 15.8 - 21.8 ) than in women ( 11.2 % , 95 % CI 8.7 - 13.6 ) . No significant differences between the sexes were found with regard to newly discovered AF ( men 1.3 % , women 0.5 % ) , potential hypertension ( men 9.7 % , women 11.5 % ) , hypercholesterolemia ( men 0.9 % , women 1.1 % ) or diabetes mellitus ( men 2.1 % , women 1.3 % ) . CONCLUSION Owing to the higher prevalence of severe conditions , such as aneurysms and CAC ≥ 400 , screening for CVD seemed more prudent in men than women . The attendance rates were acceptable compared with other screening programs and the logistical structure of the screening program proved successful Background : Asymptomatic atrial fibrillation ( AF ) is increasingly common in the aging population and implicated in many ischemic strokes . Earlier identification of AF with appropriate anticoagulation may decrease stroke morbidity and mortality . Methods : We conducted a r and omized controlled trial of AF screening using an AliveCor Kardia monitor attached to a WiFi-enabled iPod to obtain ECGs ( iECGs ) in ambulatory patients . Patients ≥65 years of age with a CHADS-VASc score ≥2 free from AF were r and omized to the iECG arm or routine care ( RC ) . iECG participants acquired iECGs twice weekly over 12 months ( plus additional iECGs if symptomatic ) onto a secure study server with overread by an automated AF detection algorithm and by a cardiac physiologist and /or consultant cardiologist . Time to diagnosis of AF was the primary outcome measure . The overall cost of the devices , ECG interpretation , and patient management were captured and used to generate the cost per AF diagnosis in iECG patients . Clinical events and patient attitudes/experience were also evaluated . Results : We studied 1001 patients ( 5 
    Output:
    