They also have an increased risk for thromboembolism .
Comparing with age-matched controls , the relative risk for stroke is increased 2- to 7-fold in patients with nonrheumatic atrial fibrillation ( 3 , 8 , 13 ) , and the absolute risk for stroke is between 1 % and 5 % per year , depending on clinical characteristics ( 3 , 12 , 14 - 16 ) .
Paroxysmal atrial fibrillation disrupts the lives of patients ( 17 ) , but this perception may not be associated with frequency or duration of symptoms .
Warfarin therapy affects quality of life because of frequent blood testing and recommendations for limiting some activities .
Data Synthesis Does Aggressive Rhythm Control Improve Mortality and Morbidity Compared with Rate Control ?
Atrial fibrillation is the most common type of arrhythmia in adults , accounting for about one third of hospitalizations for arrhythmia ( 1 ) .
The prevalence increases from less than 1 % in persons younger than 60 years of age to more than 8 % in those older than 80 years of age ( 2 - 6 ) .
The incidence ranges from 0.2 % per year for men 30 to 39 years of age to 2.3 % per year in men 80 to 89 years of age ( 7 , 8) .
The age-adjusted incidence for women is about half that of men ( 9 ) .
The cardiac conditions most commonly associated with atrial fibrillation are rheumatic mitral valve disease , coronary artery disease , congestive heart failure , and hypertension ( 8 , 10 ) .
Noncardiac causes include hyperthyroidism , hypoxic conditions , surgery , and alcohol intoxication .
A predisposing condition exists in more than 90 % of cases ( 5 , 11 , 12 ) ; the remaining cases have what is called lone atrial fibrillation .
Patients with atrial fibrillation frequently have symptoms of hemodynamic compromise , ranging from irregular palpitations to the more insidious feeling of malaise .
Little is known about the direct effects of antiarrhythmic therapy and rate-control therapy on quality of life .
The American College of Cardiology/American Heart Association/European Society of Cardiology Task Force on Clinical Guidelines for the Management of Atrial Fibrillation classified atrial fibrillation into 4 types ( 20 ) : first detected episode , paroxysmal ( terminates spontaneously ) , persistent ( electrical or pharmacologic termination necessary ) , and permanent ( resistant to electrical or pharmacologic conversion or accepted by the physician ) .
The purpose of this review was to summarize the evidence that was available during formulation of the guidelines developed by the American College of Physicians ( ACP ) and the American Academy of Family Physicians ( AAFP ) for management of adult patients with nonpostoperative atrial fibrillation .
Although the relative benefits and risks of rate versus rhythm control are of paramount importance in the management of atrial fibrillation , studies directly addressed this issue only recently .
Transesophageal echocardiographic correlates of thromboembolism in high-risk patients with nonvalvular atrial fibrillation. The Stroke Prevention in Atrial Fibrillation Investigators Committee on Echocardiography.
The risk for ischemic stroke in patients with atrial fibrillation is related to underlying structural heart disease [ 1 - 3 ] . Although most strokes are believed to arise from embolism of left atrial thrombi [ 4 , 5 ] , other mechanisms may contribute . Transesophageal echocardiography ( TEE ) provides a unique diagnostic window for evaluating the left atrium , left atrial appendage , and thoracic aorta , but the manner in which specific TEE findings in patients with atrial fibrillation correlate with thromboembolic risk and response to therapy has not been fully established [ 6 - 13 ] . We performed TEE in patients with nonvalvular atrial fibrillation who were at high intrinsic risk for thromboembolism and were participating in the Stroke Prevention in Atrial Fibrillation ( SPAF-III ) study , a r and omized clinical trial . In that study , adjusted-dose warfarin ( target international normalized ratio [ INR ] , 2 to 3 ) was compared with combination therapy consisting of low-intensity warfarin ( INR , 1.2 to 1.5 ) plus aspirin , 325 mg/d . The trial was stopped after an interim analysis indicated that the efficacy of adjusted-dose warfarin therapy was superior to that of combination therapy . Low anticoagulation intensity in the combination therapy group yielded high stroke rates that were similar to those expected during treatment with aspirin alone [ 14 , 15 ] . In the current analysis , we 1 ) correlate TEE observations among patients with atrial fibrillation at high risk for thromboembolism with rate of subsequent stroke and 2 ) compare treatment responses . Methods Patients Patients were recruited from the SPAF-III multicenter trial , which was design ed to compare two antithrombotic medication regimens for prevention of ischemic stroke and systemic embolism ( primary events ) . The study , whose design is described else-where in detail [ 14 ] , involved patients with nonvalvular atrial fibrillation who were stratified for risk on the basis of clinical and transthoracic echocardiographic criteria derived from previous analyses [ 15 ] . Women older than 75 years of age and patients of any age and either sex with systolic hypertension ( systolic blood pressure > 160 mm Hg ) , previous thromboembolism , or impaired left ventricular function ( M-mode echocardiographic fractional shortening of 0.25 or recent clinical congestive heart failure ) were r and omly assigned to receive adjusted-dose warfarin ( target INR , 2.0 to 3.0 ) or a combination of low-intensity warfarin ( 0.5 to 3.0 mg/d ; dose was initially adjusted to cause deviation of the INR to 1.2 to 1.5 and was then fixed ) and aspirin . Seventy-three percent of the patients were receiving warfarin at various dose intensities before trial entry ; these patients were equally distributed between assigned treatment groups . Antithrombotic treatment was assigned before performance of TEE and was not influenced by TEE findings . Patients were followed monthly by telephone and in clinic every 3 months , and a st and ard question naire on stroke symptoms was administered annually . All patients whose responses to the question naire suggested the occurrence of stroke were referred for clinical examination by a local affiliated neurologist who was blinded to treatment , and all events were adjudicated by a blinded event verification committee [ 14 ] . This project was design ed to supplement the SPAF-III clinical trial on the basis of the hypothesis that spontaneous echocardiographic contrast detected by TEE identifies patients at high risk for thromboembolism for whom adjusted-dose warfarin  would prove superior to  combination therapy . All participants in the parent study were encouraged , but not required , to provide separate , written informed consent for TEE after r and om assignment to antithrombotic treatment . This was done to prevent the results of TEE from influencing recruitment of patients into the trial or from altering treatment . The intended sample size of 412 TEE examinations was selected to detect an absolute difference in event rates of 3.9 % per year ( based on projected event rates of 5.4 % per year in patients with spontaneous echocardiographic contrast and 1.5 % per year in patients without contrast ) over a mean observation period of 2.5 years . Secondary objectives were to correlate clinical thromboembolic events with function of the left atrial appendage , thrombus of the left atrium and left atrial appendage , and atherosclerotic lesions in the thoracic aorta imaged by TEE . Transesophageal Echocardiography Transesophageal echocardiography was performed within 3 months of enrollment with patients under light sedation and topical anesthesia , according to specific protocol s for acquisition and interpretation [ 16 ] . Commercially available ultrasonography equipment incorporated biplane or multiplane transducers with at least 48 crystals operating at a st and ard frequency of 5 MHz with gray-scale imaging . Signal processing , log compression , and persistence values were established for each manufacturer . Images were interpreted locally , and data were entered into st and ardized forms by echocardiographers who were blinded to antithrombotic treatment assignment but not to patient demographic or clinical features . Original videotaped recordings were collected in a central echocardiographic registry for validation and quality control . To assure generalizability of the results to laboratories used in clinical practice , the analyses reported here are based on image interpretation at the local laboratories . The following features were specifically assessed : left atrial appendage size , peak ante grade ( emptying ) velocity of blood flow in the left atrial appendage , spontaneous echocardiographic contrast in the left atrium or left atrial appendage , thrombus of the left atrium or left atrial appendage , and atherosclerotic disease of the thoracic aorta . Spontaneous echocardiographic contrast was defined as a pattern of slowly swirling intracavitary echodensities imaged with gain setting s adjusted to distinguish background noise . Contrast was classified as faint when visualized intermittently during the cardiac cycle or when enhanced gain setting s were required for detection and was classified as dense when continuously present at st and ard gain . Aortic plaque was classified by location and as either simple or complex according to mobility , ulceration , pedunculation , or thickness greater than 4 mm [ 16 ] . We postulated that reduced emptying velocity from the left atrial appendage , which reflects stasis , would be associated with dense spontaneous echocardiographic contrast and thrombus formation , whereas complex aortic plaque would be a consequence of atherosclerotic vascular abnormality . We also postulated that these findings would predispose patients to ischemic stroke through separate pathogenic mechanisms . Statistical Analysis The analyses reported here were limited to variables accessible only by TEE and were hypothesized a priori to have potential predictive relations to clinical thromboembolism . Baseline comparisons between groups were done by using the chi-square test for categorical data and the Student t-test for continuous variables . The Cox proportional-hazards regression model was used to estimate the univariate relative risk associated with TEE characteristics . The primary analysis compared rates of cerebral ischemic events and systemic embolism among patients who had dense spontaneous echocardiographic contrast detected in the left atrium or left atrial appendage with rates in patients who did not have dense contrast ; the log-rank statistic was used to compare the times to events between these groups . Secondary analyses , conducted similarly , compared event rates in groups that were identified by left atrial appendage size , flow velocity , thrombus , and aortic plaque . For these comparisons , the area of the left atrial appendage was dichotomized at the upper quartile ; flow velocity was dichotomized at the lower quartile . When interaction was seen between treatment and TEE characteristics , analysis of the relation of TEE findings to events was confined to the combination therapy group and treatment effect was described separately ; when no interaction was seen , the analysis was stratified by therapy . The relative reduction in event rate associated with adjusted-dose warfarin therapy was computed as the difference between unity and the rate ratio determined by a Poisson regression model [ 17 ] . A Cox proportional-hazards regression model was fit to confirm the independence of TEE characteristics identified as univariate thromboembolic risk factors . Confidence intervals for event rates were calculated by using a Poisson regression model ; tests of significance were two-sided and were not adjusted for multiple comparisons . All analyses were done according to the intention-to-treat principle . Results Of 1044 high-risk patients with atrial fibrillation enrolled in the r and omized trial , 382 ( 37 % ) volunteered for TEE ( range , 10 % to 80 % of SPAF-III participants recruited at 18 clinical centers offering TEE ) . Salient features of these 382 patients were similar to those of the 662 participants who did not undergo transesophageal imaging ( Table 1 ) . The mean patient age was 71 years , 36 % of patients had clinical ischemic heart disease , and almost half had a history of congestive heart failure . Balanced proportions of patients were assigned to therapy with adjusted-dose warfarin ( n = 190 ) or fixed-dose warfarin and aspirin ( n = 192 ) . Time from r and om assignment of treatment to TEE was similar in the two groups ( mean , 23 days ) . The trial was stopped after a mean observation period of 1.1 years because an interim analysis indicated the lack of efficacy of the combination regimen [ 18 ] . Up to that point , 23 primary events ( all of which were ischemic strokes ) occurred in the subset of participants who had undergone TEE ( event rate , 3.1 % per year in patients assigned to adjusted-dose warfarin compared with 7.8 % per year in those assigned to combination therapy ; P = 0.04 ) .
They also have an increased risk for thromboembolism .
Comparing with age-matched controls , the relative risk for stroke is increased 2- to 7-fold in patients with nonrheumatic atrial fibrillation ( 3 , 8 , 13 ) , and the absolute risk for stroke is between 1 % and 5 % per year , depending on clinical characteristics ( 3 , 12 , 14 - 16 ) .
Paroxysmal atrial fibrillation disrupts the lives of patients ( 17 ) , but this perception may not be associated with frequency or duration of symptoms .
Warfarin therapy affects quality of life because of frequent blood testing and recommendations for limiting some activities .
Data Synthesis Does Aggressive Rhythm Control Improve Mortality and Morbidity Compared with Rate Control ?
Atrial fibrillation is the most common type of arrhythmia in adults , accounting for about one third of hospitalizations for arrhythmia ( 1 ) .
The prevalence increases from less than 1 % in persons younger than 60 years of age to more than 8 % in those older than 80 years of age ( 2 - 6 ) .
The incidence ranges from 0.2 % per year for men 30 to 39 years of age to 2.3 % per year in men 80 to 89 years of age ( 7 , 8) .
The age-adjusted incidence for women is about half that of men ( 9 ) .
The cardiac conditions most commonly associated with atrial fibrillation are rheumatic mitral valve disease , coronary artery disease , congestive heart failure , and hypertension ( 8 , 10 ) .
Noncardiac causes include hyperthyroidism , hypoxic conditions , surgery , and alcohol intoxication .
A predisposing condition exists in more than 90 % of cases ( 5 , 11 , 12 ) ; the remaining cases have what is called lone atrial fibrillation .
Patients with atrial fibrillation frequently have symptoms of hemodynamic compromise , ranging from irregular palpitations to the more insidious feeling of malaise .
Little is known about the direct effects of antiarrhythmic therapy and rate-control therapy on quality of life .
The American College of Cardiology/American Heart Association/European Society of Cardiology Task Force on Clinical Guidelines for the Management of Atrial Fibrillation classified atrial fibrillation into 4 types ( 20 ) : first detected episode , paroxysmal ( terminates spontaneously ) , persistent ( electrical or pharmacologic termination necessary ) , and permanent ( resistant to electrical or pharmacologic conversion or accepted by the physician ) .
The purpose of this review was to summarize the evidence that was available during formulation of the guidelines developed by the American College of Physicians ( ACP ) and the American Academy of Family Physicians ( AAFP ) for management of adult patients with nonpostoperative atrial fibrillation .
Although the relative benefits and risks of rate versus rhythm control are of paramount importance in the management of atrial fibrillation , studies directly addressed this issue only recently .