There is limited evidence to suggest which ablation method was the best .
There is limited evidence to suggest that CA may be a better treatment option compared to medical therapies in the management of persistent AF .
This review was also unable to recommend the best CA method
BACKGROUND Atrial fibrillation ( AF ) is the most common cardiac arrhythmia seen in cardiovascular departments .
Treatments include medical interventions and catheter ablation .
Due to uncertainties in medical therapies for AF , and the need to continue sinus rhythm , ablation has been recently considered as a viable alternative .
Many new ablation methods based on pulmonary vein isolation ( PVI ) have been developed .
OBJECTIVES The primary objective of this review was to assess the beneficial and harmful effects of  catheter ablation ( CA ) in comparison with medical treatment in patients with paroxysmal and persistent AF .
The secondary objective was to determine the best regimen of CA .
Risk Factors for Intracranial Hemorrhage in Outpatients Taking Warfarin
Intracranial hemorrhage is the most feared complication of anticoagulant therapy . Outcomes are frequently catastrophic , often result ing in death or severe neurologic disability . The effect of intracranial hemorrhage is as great as that of the thromboembolic events warfarin is used to prevent . As a result , the risk for intracranial hemorrhage is a critical feature of the decision to use anticoagulation [ 1 ] . The indications for use of anticoagulants are exp and ing , particularly among older patients . For example , anticoagulant therapy is now recommended to prevent stroke in patients with atrial fibrillation [ 2 - 6 ] , and it has been found to significantly improve outcome in patients after myocardial infa rct ion [ 7 ] . Clinical trials of warfarin as primary preventive therapy for ischemic heart disease are ongoing [ 8 ] . With this increase in the use of long-term warfarin therapy , there is a pressing need to identify clinical features that raise the risk of its most severe bleeding complications . No previous study has identified independent risk factors for intracranial hemorrhage among patients taking warfarin .  Previous prospect i ve analytic studies that focused on the entire spectrum of major bleeding complications have contained few cases of intracranial hemorrhage [ 9 - 11 ] . We design ed a casecontrol study focused exclusively on intracranial hemorrhage occurring among out patients taking warfarin .  We drew on an 11-year experience of one general hospital to provide case- patients and used the same hospital 's large anticoagulant therapy unit to provide contemporaneous controls who were also taking warfarin .  This design was chosen to increase statistical power for detecting risk factors for intracranial hemorrhage while reducing possible bias . Methods Case-Patient Identification and Eligibility Using a discharge log of consecutive admissions to the Massachusetts General Hospital during the period from 1 January 1981 through 31 December 1991 , we identified 1881 patients with a principal diagnosis of intracranial hemorrhage ( ICD-9 codes 430 , 431 , 432.0 , 432.1 , and 432.9 ) . Forty-one ( 2 % ) medical records for these patients could not be located . In the remaining 1840 case- patients , warfarin use was determined from review of the neurologist , neurosurgery resident , and attending staff physician admission notes . Intracranial hemorrhage was verified by computed tomographic ( CT ) scanning , lumbar puncture , or postmortem examination in all but one case-patient . In this latter case-patient , the diagnosis was based on clinical grounds because the patient died before diagnostic studies were done and no autopsy was performed . To be eligible for the study , patients had to be at least 18 years old and taking warfarin as an outpatient . Patients with an anatomic abnormality or underlying bleeding diathesis predisposing to intracranial hemorrhage , regardless of anticoagulant therapy , were not included . Hemorrhages sustained as a result of major head trauma ( with skull fracture and loss of consciousness ) also were not eligible . Of 131 patients with intracranial hemorrhage identified , 10 were excluded as ineligible : Four patients had subarachnoid hemorrhage result ing from angiographically identified intracranial aneurysms ; 2 had hemorrhage into primary or metastatic tumors ; 2 had acute subdural hemorrhage after major head trauma ; 1 bled after multiple craniotomies and radiation therapy for a recurrent craniopharyngioma ; and another patient had aplastic anemia . Controls : Source and Matching Controls were selected from the registry of the Massachusetts General Hospital 's anticoagulant therapy unit . During the study period , this unit managed  warfarin dosing for approximately 8000 patients referred from all hospital clinical services . The most common indications for anticoagulation were atrial fibrillation , previous stroke , presence of prosthetic heart valves , and venous thromboembolism . Approximately 40 % of the patients managed by the anticoagulant therapy unit have prothrombin time tests done at the Massachusetts General Hospital . An additional 20 % have their prothrombin times measured at one large commercial laboratory ( via home phlebotomy services ) . The remaining 40 % have their tests done at various local laboratories . Each case-patient was matched to three r and omly selected controls taking warfarin at the time of the case-patient 's intracranial hemorrhage . Matching was accomplished by first identifying all patients managed by the anticoagulant therapy unit at the date of hospital admission for the given case-patient . Each potential control was assigned a r and om number . The three controls with the lowest r and om numbers were selected . No control was used more than once . Three controls subsequently became case- patients . Matching was done to control for any change in background risk over the 11-year study period ( for example , from changes in prothrombin time targets or technique of measuring the prothrombin time ) . Data Collected Clinical features of case- patients and controls were extracted primarily from hospital records , with supplementation in a few instances from physician office records . Variables were entered on a pre design ed data form and included indication for anticoagulant therapy ; race ; sex ; age ; prothrombin time ratio ( PTR ) ; duration of warfarin therapy ; history of diagnosed hypertension , stroke , transient ischemic attack , diabetes mellitus , myocardial infa rct ion , atrial fibrillation , and congestive heart failure ; and medications . Clinical features of the intracranial hemorrhages were also recorded . Clinical data for the controls were current at the admission date of the matched case-patient with intracranial hemorrhage . The prothrombin time ratio was expressed as the ratio of the patient 's value divided by the simultaneously reported control value . For case- patients , we used the PTR on admission , or , if available , the PTR closest to the reported onset of symptoms . For controls , the PTR closest to that of the case-patient admission date was recorded from the anticoagulant therapy unit data base . Because values for the international sensitivity index ( ISI ) for thromboplastins were not universally reported before 1988 , we analyzed our data using the PTR rather than the international normalized ratio ( INR ) . Since 1988 , Massachusetts General Hospital 's hematology laboratory has used Simplastin Automated ( Organon Teknika Corporation , Durham , North Carolina ) , with values for the ISI ranging from 1.9 to 2.0 . During the study period , this company ( previously General Diagnostics ) supplied the thromboplastin and assisted our laboratory in selecting lots of comparable sensitivity . Studies were routinely done to minimize year-to-year variation in thromboplastin sensitivity . Since 1988 , the most frequently used commercial laboratory has used thromboplastins with ISI values ranging from 1.9 to 2.1 . The PTR was missing for four case- patients ; the data for case- patients and controls were otherwise complete . Selected Relevant Definitions Hypertension was defined as probable if the patient had such a diagnosis listed in the medical record and as definite if the patient was receiving antihypertensive medication . When hypertension was diagnosed , it was classified as definite 97 % of the time for case- patients and 93 % of the time for controls . All diagnoses of hypertension are used in the analyses . Patients with documented carotid or vertebrobasilar disease and those with a history of previous stroke were defined as having cerebrovascular disease . Diagnoses of carotid or vertebrobasilar disease or both were confirmed by angiography in 71 % of case- patients and 93 % of controls , by Doppler studies in 17 % of case- patients and 2 % of controls , and solely by assessment by a neurologist in 12 % of case- patients and 5 % of controls . Statistical Analysis Case- patients and controls were compared using chi-square tests and the Fisher exact test , where appropriate , for categorical variables and using the Student t-test for continuous variables . Univariate odds ratios were calculated using unmatched and matched techniques . The matched odds ratios were provided by the Mantel-Haenszel [ 12 ] summary statistic across matched sets . The unmatched and matched techniques provided very similar estimates of odds ratios . We report the unmatched results . Confidence intervals for odds ratios were calculated using the Taylor series method [ 13 ] . The test of trend was done using the Cochran-Mantel-Haenszel test [ 14 ] . Logistic regression models assessed the independent effect of multiple clinical features and the significance of interaction terms . Conditional logistic models [ 15 ] accounting for matching provided estimates similar to those of the unmatched logistic regression analyses . The estimates from the unmatched analyses are reported . Data were recorded in R : BASE ( Microrim , Bellevue , Washington ) from the paper data forms . Statistical analyses were done using SAS ( SAS Institute Inc. , Cary , North Carolina ) and GLIM ( Numerical Algorithms Group Limited , Oxford , United Kingdom ) . Results Clinical Course of Case- Patients During the 11-year study period , 121 patients with intracranial hemorrhage were eligible ; 77 hemorrhages were intracerebral and 44 were subdural ( Table 1 ) . Three of the patients with subdural hemorrhage had a history of trivial head trauma ; the others had no known antecedent head trauma . For the patients with intracerebral hemorrhages , headache was the most common presenting feature ( 53 % ) , followed by nausea and vomiting ( 40 % ) and unresponsiveness ( 36 % ) . Seventy-eight percent of the case- patients presented to the emergency department within 24 hours of the onset of symptoms and 87 % within 48 hours . In contrast , only 36 % of the patients with subdural bleeding came to medical attention within this same period . Forty-six percent of patients with intracerebral bleeding died , and 17 % survived with major neurologic deficits that prevented subsequent independent living . Table 1 .
There is limited evidence to suggest which ablation method was the best .
There is limited evidence to suggest that CA may be a better treatment option compared to medical therapies in the management of persistent AF .
This review was also unable to recommend the best CA method
BACKGROUND Atrial fibrillation ( AF ) is the most common cardiac arrhythmia seen in cardiovascular departments .
Treatments include medical interventions and catheter ablation .
Due to uncertainties in medical therapies for AF , and the need to continue sinus rhythm , ablation has been recently considered as a viable alternative .
Many new ablation methods based on pulmonary vein isolation ( PVI ) have been developed .
OBJECTIVES The primary objective of this review was to assess the beneficial and harmful effects of  catheter ablation ( CA ) in comparison with medical treatment in patients with paroxysmal and persistent AF .
The secondary objective was to determine the best regimen of CA .