Kowey, Peter R.

Background The characteristics of patients undergoing atrial fibrillation ( AF ) ablation and subsequent outcomes in community practice are not well described. Methods and Results Using the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation ( ORBIT ‐ AF ), we investigated the prevalence and impact of catheter ablation of AF . Among 9935 patients enrolled, 5.3% had previous AF ablation. Patients with AF ablation were significantly younger, more frequently male, and had less anemia, chronic obstructive pulmonary disease, and previous myocardial infarction (P<0.05 for all analyses) than those without previous catheter ablation of AF . Ablated patients were more likely to have a family history of AF , obstructive sleep apnea, paroxysmal AF , and moderate‐to‐severe symptoms (P<0.0001 for all analyses). Patients with previous ablation were more often in sinus rhythm on entry into the registry (52% vs. 32%; P<0.0001). Despite previous ablation, 46% in the ablation group were still on antiarrhythmic therapy. Oral anticoagulation was prescribed in 75% of those with previous ablation versus 76% in those without previous ablation (P=0.5). The adjusted risk of death (hazard ratio [ HR ], 0.78; 95% confidence interval [ CI ], 0.52 to 1.18; P=0.2) and cardiovascular ( CV ) hospitalization ( HR , 1.06; 95% CI , 0.90 to 1.26; P=0.5) were similar in both groups. Patients with incident AF ablation had higher risk of subsequent CV hospitalization than matched patients without incident ablation ( HR , 1.67; 95% CI , 1.24 to 2.26; P=0.0008). Conclusions In U.S. clinical practice, a minority of patients with AF are managed with catheter ablation. Subsequent to ablation, there were no significant differences in oral anticoagulation use or outcomes, including stroke/non–central nervous system embolism/transient ischemic attack or death. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifier: NCT 01165710.

Objective Atrial fibrillation (AF) often progresses from paroxysmal or persistent to more sustained forms, but the rate and predictors of AF progression in clinical practice are not well described. Methods Using the Outcomes Registry for Better Informed Treatment of AF, we analysed the incidence and predictors of progression and tested the discrimination and calibration of the HATCH (hypertension, age, TIA/stroke, chronic obstructive pulmonary disease, heart failure) and CHA2DS2VASc scores for identifying AF progression. Results Among 6235 patients with paroxysmal or persistent AF at baseline, 1479 progressed, during follow-up (median 18 (IQR 12–24) months). These patients were older and had more comorbidities than patients who did not progress (CHADS2 2.3±1.3 vs 2.1±1.3, p<0.0001). At baseline, patients with AF progression were more often on a rate control as opposed to a rhythm control strategy (66 vs 56%, p<0.0001) and had higher heart rate (72(64–80) vs 68(60–76) bpm, p<0.0001). The strongest predictors of AF progression were AF on the baseline ECG (OR 2.30, 95% CI 1.95 to 2.73, p<0.0001) and increasing age (OR 1.16, 95% CI1.09 to 1.24, p<0.0001, per 10 increase), while patients with lower heart rate (OR 0.84, 95% CI 0.79 to 0.89, p<0.0001, per 10 decrease ≤80) were less likely to progress. There was no significant interaction between rhythm on baseline ECG and heart rate (p=0.71). The HATCH and CHA2DS2VASc scores had modest discriminatory power for AF progression (C-indices 0.55 (95% CI 0.53 to 0.58) and 0.55 (95% CI 0.52 to 0.57)). Conclusions Within 1.5 years, almost a quarter of the patients with paroxysmal or persistent AF progress to a more sustained form. Progression is strongly associated with heart rate, and age.

Background— Temporary interruption of oral anticoagulation for procedures is often required, and some propose using bridging anticoagulation. However, the use and outcomes of bridging during oral anticoagulation interruptions in clinical practice are unknown. Methods and Results— The Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) registry is a prospective, observational registry study of US outpatients with atrial fibrillation. We recorded incident temporary interruptions of oral anticoagulation for a procedure, including the use and type of bridging therapy. Outcomes included multivariable-adjusted rates of myocardial infarction, stroke or systemic embolism, major bleeding, cause-specific hospitalization, and death within 30 days. Of 7372 patients treated with oral anticoagulation, 2803 overall interruption events occurred in 2200 patients (30%) at a median follow-up of 2 years. Bridging anticoagulants were used in 24% (n=665), predominantly low-molecular-weight heparin (73%, n=487) and unfractionated heparin (15%, n=97). Bridged patients were more likely to have had prior cerebrovascular events (22% versus 15%; P =0.0003) and mechanical valve replacements (9.6% versus 2.4%; P <0.0001); however, there was no difference in CHA 2 DS 2 -VASc scores (scores ≥2 in 94% versus 95%; P =0.5). Bleeding events were more common in bridged than nonbridged patients (5.0% versus 1.3%; adjusted odds ratio, 3.84; P <0.0001). The incidence of myocardial infarction, stroke or systemic embolism, major bleeding, hospitalization, or death within 30 days was also significantly higher in patients receiving bridging (13% versus 6.3%; adjusted odds ratio, 1.94; P =0.0001). Conclusions— Bridging anticoagulation is used in one quarter of anticoagulation interruptions and is associated with higher risk for bleeding and adverse events. These data do not support the use of routine bridging, and additional data are needed to identify best practices concerning anticoagulation interruptions. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01165710.

Background Dabigatran is a novel oral anticoagulant approved for thromboprophylaxis in atrial fibrillation. Adoption patterns of this new agent in community practice are unknown. Methods and Results We studied patterns of dabigatran use among patients enrolled in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT‐AF) Registry between June 2010 and August 2011 and followed for 12 months. Among 9974 atrial fibrillation patients included, 1217 (12%) were treated with dabigatran during the study. Overall, patients receiving dabigatran were younger (median age 72 versus 75 years, P <0.0001), more likely to be white (92% versus 89%, P =0.005), more likely to have private insurance (33% versus 25%, P <0.0001), and less likely to have prior cardiovascular disease (4% versus 33%, P <0.0001). They had more new‐onset atrial fibrillation (8.8% versus 4.1%, P <0.0001), lower CHADS 2 scores (estimated risk based on the presence of congestive heart failure, hypertension, aged ≥75 years, diabetes mellitus, and prior stroke or transient ischemic attack; mean 2.0 versus 2.3, P <0.0001), and lower Anticoagulation and Risk Factors in Atrial Fibrillation scores (mean 2.4 versus 2.8, P <0.0001). More than half (n=14/25, 56%) of patients with severe kidney disease were not prescribed reduced dosing, whereas 10% (n=91/920) with preserved renal function received lower dosing. Among patients not on dabigatran at baseline, 8% had dabigatran initiated during follow‐up. Patient education was significantly associated with switching from warfarin to dabigatran (adjusted odds ratio for postgraduate 1.73, P =0.007), whereas antiarrhythmic drug use significantly correlated with de novo adoption of dabigatran (adjusted odds ratio 2.4, P <0.0001). Conclusions Patients receiving dabigatran were younger and at a lower risk of stroke and bleeding. Patients appeared to drive switching from warfarin, whereas clinical characteristics influenced de novo start of dabigatran. These data suggest cautious early uptake of dabigatran, and more careful attention to dosing adjustments is warranted. Clinical Trial Registration URL : Clinicaltrials.gov. Unique identifier: NCT 01165710.

Background The prevalence of atrial fibrillation ( AF ) continues to increase; however, there are limited data describing the division of care among practitioners in the community and whether care differs depending on provider specialty. Methods and Results Using the Outcomes Registry for Better Informed Treatment of AF ( ORBIT ‐ AF ) Registry, we described patient characteristics and AF management strategies in ambulatory clinic practice settings, including electrophysiology ( EP ), general cardiology, and primary care. A total of 10 097 patients were included; of these, 1544 (15.3%) were cared for by an EP provider, 6584 (65.2%) by a cardiology provider, and 1969 (19.5%) by an internal medicine/primary care provider. Compared with those patients who were cared for by cardiologists or internal medicine/primary care providers, patients cared for by EP providers were younger (median age, 73 years [interquartile range, IQR , 64, 80 years, Q1, Q3] versus 75 years [ IQR , 67, 82 years] for cardiology and versus 76 years [ IQR , 68, 82 years] for primary care). Compared with cardiology and internal medicine/primary care providers, EP providers used rhythm control (versus rate control) management more often (44.2% versus 29.7% and 28.8%, respectively, P <0.0001; adjusted odds ratio [ OR ] EP versus cardiology, 1.66 [95% confidence interval, CI , 1.05 to 2.61]; adjusted OR for internal medicine/primary care versus cardiology, 0.91 [95% CI , 0.65 to 1.26]). Use of oral anticoagulant therapy was high across all providers, although it was higher for cardiology and EP providers (overall, 76.1%; P =0.02 for difference between groups). Conclusions Our data demonstrate important differences between provider specialties, the demographics of the AF patient population treated, and treatment strategies—particularly for rhythm control and anticoagulation therapy.

Background— Patients with atrial fibrillation (AF) at the highest stroke risk derive the largest benefit from oral anticoagulation (OAC). Those with the highest stroke risk have been paradoxically less likely to receive OAC. This study assessed the association between stroke and bleeding risk on rates of OAC. Methods and Results— We analyzed OAC use among 10 098 patients with AF from 174 community-based outpatient practices enrolled in 2010–2011 in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). OAC was defined as warfarin or dabigatran use at study enrollment. Stroke and bleeding risk were calculated using congestive heart failure, hypertension, age, diabetes mellitus, prior stroke (CHADS 2 ), and anticoagulation and risk factors in AF (ATRIA) scores, respectively. The mean subject age was 73 years; 58% were men. Overall, 76% of patients received OAC (71% warfarin and 5% dabigatran). The use of OAC increased among those with higher CHADS 2 scores, from 53% for CHADS 2 =0 to 80% for CHADS 2 ≥2 ( P <0.001). OAC use fell slightly with increasing ATRIA bleeding risk score, from 81% for ATRIA=3 to 73% for ATRIA≥5 ( P <0.001). A significant interaction existed between ATRIA and CHADS 2 scores ( P =0.021). Among those with low bleeding risk, use of OAC increased significantly with increasing stroke risk. Among those with high bleeding risk, CHADS 2 stroke risk had a smaller impact on use of OAC. Conclusions— In community-based outpatients with AF, use of OAC was high and driven by not only predominantly stroke but also bleeding risk. Stroke risk significantly affects OAC use among those with low bleeding risk, whereas those with high bleeding risk demonstrate consistently lower use of OAC regardless of stroke risk.