Reiffel, James A.

Abstract Atrial fibrillation (AF) is increasingly diagnosed early, close to its first occurrence due to: (i) increased public awareness with self-screening; (ii) health care initiatives including population screening and opportunistic case finding; and (iii) increased use and surveillance of implantable cardiac devices. At its onset, AF is often low burden, and cardiovascular co-morbidities may be absent or at an early stage. Thus, the management of recent-onset AF has become an issue of growing importance. Professional guidelines have traditionally focused on anticoagulant thromboprophylaxis, generally recommending a cautious approach to rhythm control, and priority has been given to rate control to alleviate symptoms. In recent guidelines, the importance of managing lifestyle and co-morbidities has increased. The AF-SCREEN collaboration proposes that a vigorous approach to active management of recent-onset AF may be warranted. This includes addressing co-morbidities and promoting healthy lifestyles to prevent the emergence or progression of AF and associated cardiovascular disease, as well as the initiation of active rhythm control ± anticoagulation to prevent AF-related morbidity and mortality, including stroke and heart failure (HF). Intuitively, intervention early after AF onset would be beneficial since lifestyle and co-morbidity management, plus rhythm control and anticoagulation, are important contributors to improved outcomes in patients with established AF, but robust evidence is lacking for recent-onset AF. There is a delicate balance between achieving favourable outcomes such as preventing strokes, HF and AF progression vs the complications and potential adverse effects of interventions. Given the serious long-term consequences, innovative approaches are necessary to determine the value and risks of initiating active therapy very early in the course of AF. More data are needed to guide the best management of recent-onset AF, bearing AF burden in mind. Long-term studies using large national databases linked to electronic medical records and rhythm monitoring devices offer excellent opportunities. Shorter-term studies focusing on reducing AF burden to slow AF progression and studies focusing on outcomes such as HF could be used in both randomized clinical trials and observational cohort studies.

Oral anticoagulants (OACs) are medications commonly used in patients with atrial fibrillation and other cardiovascular conditions. Both warfarin and direct oral anticoagulants are susceptible to drug-drug interactions (DDIs). DDIs are an important cause of adverse drug reactions and exact a large toll on the health care system. DDI for warfarin mainly involve moderate to strong inhibitors/inducers of cytochrome P450 (CYP) 2C9, which is responsible for the elimination of the more potent S-isomer of warfarin. However, inhibitor/inducers of CYP3A4 and CYP1A2 may also cause DDI with warfarin. Recognition of these precipitating agents along with increased frequency of monitoring when these agents are initiated or discontinued will minimize the impact of warfarin DDI. Direct oral anticoagulants are mainly affected by medications strongly affecting the permeability glycoprotein (P-gp), and to a lesser extent, strong CYP3A4 inhibitors/inducers. Dabigatran and edoxaban are affected by P-gp modulation. Strong inducers of CYP3A4 or P-gp should be avoided in all patients taking direct oral anticoagulant unless previously proven to be otherwise safe. Simultaneous strong CYP3A4 and P-gp inhibitors should be avoided in patients taking apixaban and rivaroxaban. Concomitant antiplatelet/anticoagulant use confers additive risk for bleeding, but their combination is unavoidable in many cases. Minimizing duration of concomitant anticoagulant/antiplatelet therapy as indicated by evidence-based clinical guidelines is the best way to reduce the risk of bleeding.

Antiarrhythmic drugs (AAD) play an important role in the management of arrhythmias. Drug interactions involving AAD are common in clinical practice. As AADs have a narrow therapeutic window, both pharmacokinetic as well as pharmacodynamic interactions involving AAD can result in serious adverse drug reactions ranging from arrhythmia recurrence, failure of device-based therapy, and heart failure, to death. Pharmacokinetic drug interactions frequently involve the inhibition of key metabolic pathways, resulting in accumulation of a substrate drug. Additionally, over the past 2 decades, the P-gp (permeability glycoprotein) has been increasingly cited as a significant source of drug interactions. Pharmacodynamic drug interactions involving AADs commonly involve additive QT prolongation. Amiodarone, quinidine, and dofetilide are AADs with numerous and clinically significant drug interactions. Recent studies have also demonstrated increased morbidity and mortality with the use of digoxin and other AAD which interact with P-gp. QT prolongation is an important pharmacodynamic interaction involving mainly Vaughan-Williams class III AAD as many commonly used drug classes, such as macrolide antibiotics, fluoroquinolone antibiotics, antipsychotics, and antiemetics prolong the QT interval. Whenever possible, serious drug-drug interactions involving AAD should be avoided. If unavoidable, patients will require closer monitoring and the concomitant use of interacting agents should be minimized. Increasing awareness of drug interactions among clinicians will significantly improve patient safety for patients with arrhythmias.

Introduction: Randomized trials have not demonstrated significant differences in stroke, heart failure or mortality between rhythm and rate control strategies for management of atrial fibrillation (AF). The comparative outcomes in contemporary clinical practice are not well described. The objective of this study was to evaluate outcomes in clinical practice with rhythm control versus rate control strategy. Methods: Patients managed with a rhythm control strategy targeting maintenance of sinus rhythm were retrospectively compared with a strategy of rate control alone in a AF registry across various US practice settings. Unadjusted and adjusted (inverse-propensity weighted) outcomes were estimated. Results: The overall study population (n=6988) had a median age of 74 (25th, 75th percentile 65, 81) years, 56% were males, 77% had first detected or paroxysmal AF and 89% had CHA2DS2-VASc score ≥2. In unadjusted analyses, rhythm control was associated with lower all-cause death, cardiovascular death, first stroke/non-central nervous system systemic embolization/transient ischemic attack, or first major bleeding event (all p<0.05); however, rhythm control was associated with more cardiovascular hospitalizations (HR 1.24, 95% CI 1.10-1.39, p=0.0003; Figure). Conclusion: Among patients with AF in clinical practice, rhythm control was not superior to rate control strategy for outcomes of stroke, heart failure, or mortality, but was associated with more cardiovascular hospitalizations.

Background: The Atrial Fibrillation Effect on QualiTy-of-Life (AFEQT) survey has recently been validated to measure the impact of atrial fibrillation on patients’ quality of life, but a clinically important difference (CID) in AFEQT score has not been defined. Knowing the CID is needed to interpret the meaningfulness of differences between treatments in clinical trials; or patient populations for quality assessment. Objectives: To calculate CID values in AFEQT in the ORBIT registry. Methods: ORBIT-AF is a US-based outpatient AF registry that measured disease-specific QoL with the AFEQT tool (score range= 0 (worst) to 100) at baseline and at 1 year follow-up. Two anchor-based methods were used to relate changes in AFEQT to clinically important differences in the more established European Heart Rhythm Association (EHRA) measure of functional status. Ranging from 1 (no symptoms) to 4 (disabling), a change of 1 EHRA class was defined as an important change in the anchor. Both the mean change and receiver operating characteristics (ROC) methods were then used to identify CIDs in AFEQT at 1 year follow-up. This was done for both improvement and worsening on the anchor. The mean change method defines a CID as the mean change in AFEQT score among patients with a 1 EHRA class change. The ROC method identifies a CID as the point on the ROC curve that best discriminates patients who experienced an important change in the anchor (≥ 1 EHRA class change) from those who experienced no change. Results: AFEQT was assessed in 2008 AF patients at baseline and 1347 patients at 1 year from 99 US sites participating in ORBIT-AF. CIDs and 95% confidence intervals (CI) corresponding to an improvement in EHRA for the mean change method were 5.4 (3.6, 7.2) AFEQT points and 1.9 (0.4, 9.3) AFEQT points for the ROC method. CIDs corresponding to worsening in EHRA for the mean change method were -4.2 (-6.9,-1.5) AFEQT points and -7.4 (-13.9,-4.6) AFEQT points for the ROC method. Conclusions: Changes in AFEQT as small as 2 points may be clinically relevant, although CIDs vary depending on the method of calculation. The variability suggests identifying a single universal CID to assess improvement in quality of life in AF patients may not be ideal and improvement may relate to the nature of a patient’s symptoms and their baseline level of activity.

Background: With increasing options for treating atrial fibrillation (AF), it is important to understand and quantify patient symptoms and quality of life (QoL), as improving symptoms and maximizing QoL are primary treatment goals. However, little is known about the factors associated with QoL. Methods: The Atrial Fibrillation Effect on QualiTy-of-life (AFEQT) is a disease-specific QoL tool for AF, with domain and summary scores ranging from 0 (the worst health status) to 100. Using hierarchical pseudo-binomial regression, we evaluated factors associated with baseline AFEQT Summary and Subscale scores in the ORBIT AF registry. Adjusted associations were reported as odds ratios (OR) and 95% confidence intervals (CI). Results: AFEQT was assessed in 2,007 AF outpatients from 99 sites. Median age and interquartile range (IQR) was 76 (67-82); 43% were female; and the median CHA2DS2-VASC score was 4 (3-5). Median AFEQT summary score was 82 (67, 94). Median symptom score was 92 (78-100) and daily activity score was 77 (52-94). Female sex, younger age, new onset AF, higher heart rate, obstructive sleep apnea, and CAD were all associated with reduced QoL. (Table) Similar trends were seen for the symptoms subscale: female sex [OR 0.57 CI (0.48, 0.68)], younger age [OR 1.10 CI (1.06, 1.15)], and new onset AF [OR 0.55 CI (0.43, 0.70)] were associated with worse symptoms. Likewise, for the daily activities subscale, Other race [OR 0.54 CI (0.36-0.80)] and higher BMI [OR 0.98 CI (0.98-0.99)] were associated with decreased activity. Conclusions: In the largest community-based assessment of QoL in patients with AF, we found several patient factors to be associated with low QoL, including female sex, new onset AF, younger age, higher heart rate, and certain cardiopulmonary comorbidities. Understanding patient characteristics associated with worse QoL can be a foundation for eradicating disparities and tailoring treatment.

Background: Patients with sinus node dysfunction (SND) are at increased risk of atrial tachyarrhythmias, including atrial fibrillation (AF). Whether the presence of SND is also associated with worse outcomes among those with AF has not been well described. Methods: The ORBIT-AF registry enrolled patients with AF from a range of clinical practices across the US. SND was defined clinically, based on the presence of sinus bradycardia, severe sinus bradycardia, sinus arrest, sinoatrial exit block, or features of tachycardia-bradycardia syndrome. Descriptive statistics and multivariable logistic regression analysis were used to describe treatment patterns and outcomes for patients with and without SND and AF. Results: Overall, 1,710 (17.7%) patients had SND at enrollment. Patients with SND had lower left-ventricular ejection fractions, higher CHA 2 DS 2 -VASc risk scores, and more prior cerebrovascular events. Patients with SND had more severe symptoms (EHRA class IV: 17.5% vs. 13.9%; p=0.007) and poorer quality of life (median AFEQT 77.5 vs. 81.1; p=0.008) as compared to those without. SND patients were more frequently treated with oral anticoagulants (79.2% vs. 75.9%, p=0.004) and had more often received interventional therapy for AF (16.1% vs. 10.5%, p<0.0001). There were no differences in the current AF management strategy between patients with SND and those without [rate control (69.7% vs. 67.7%), rhythm control (30.0% vs. 32.0%); P=0.11]. After adjustment, significantly more patients with SND had progressed from paroxysmal AF at baseline to persistent or permanent AF at any follow-up or persistent AF at baseline to permanent AF at any follow-up than those without (OR 1.23, 95% CI 1.01-1.49, p=0.035). Conclusion: Sinus node dysfunction is associated worse symptoms, lower quality of life, and higher risk of progression to permanent AF. However, SND is not associated with increased risk of all-cause hospitalization, incident stroke, or all-cause death.

Introduction: Patient understanding of available therapies for atrial fibrillation (AF) is foundational to shared medical decision making and long term medication adherence. Yet, there is a paucity of data regarding the extent to which patients newly diagnosed with AF in routine community practice understand their options. Hypotheses: 1) Understanding of warfarin, novel oral anticoagulants (NOAC), rhythm control therapy, cardioversion and radio frequency ablation changes little from baseline to 6 months and 2) treatment rates at 6 months are associated with patient understanding of therapies at baseline. Methods: We analyzed survey data from SATELLITE, a substudy of new-onset AF patients enrolled at 56 US sites participating in the ORBIT-AF registry. Patients were surveyed at the baseline and 6 month follow up clinic visit using Likert scales. Agreement between time points was assessed with the McNemar test, and the relationship between understanding and treatment was assessed only for the subset not on treatment at baseline. Results: Of 1000 patients enrolled in SATELLITE, 506 had 6-month survey data (data collection is continuing). Among these, the median age was 69.0 years (IQR 63.0 - 76.0) and 93.7% (474 of 506) were white. There was evidence of improvement in the self-reported understanding of warfarin and NOACs from baseline to 6 months, but not for rhythm control, ablation or cardioversion. The proportion reporting high understanding improved significantly for warfarin (p<.0001) and NOACs (p<.0001) from 47% (223 of 474) and 51% (245 of 481) at baseline to 60% (284 of 474) and 69% (332 of 481) at 6 months respectively (Figure 1). Patients with high understanding of the benefits of ablation (p=0.0005) and options for ablation (p=0.0093) at baseline were more likely to have this therapy at the 6 month follow up (N=590), but improved understanding was not associated with increased use of warfarin/NOACs (N=83) or rhythm control (N=444). Conclusions: Patients with new-onset AF had improved self-reported understanding of some treatment options over the first 6-months from diagnosis; however, factors other than patient understanding may influence AF treatments received at 6 months. Patient understanding of AF treatments remains suboptimal at 6 months, and our results suggest a need for ongoing patient education.

Background Cardioversion is common among patients with atrial fibrillation (AF). We hypothesised that novel oral anticoagulants (NOAC) used in clinical practice resulted in similar rates of stroke compared with vitamin K antagonists (VKA) for cardioversion. Methods Using the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II, patients with AF who had a cardioversion, follow-up data and an AF diagnosis within 6 months of enrolment were identified retrospectively. Clinical outcomes were compared for patients receiving a NOAC or VKA for 1 year following cardioversion. Results Among 13 004 patients with AF, 2260 (17%) underwent cardioversion. 1613 met the inclusion criteria for this analysis. At the time of cardioversion, 283 (17.5%) were receiving a VKA and 1330 (82.5%) a NOAC. A transoesophageal echocardiogram (TOE) was performed in 403 (25%) cardioversions. The incidence of stroke/transient ischaemic attack (TIA) at 30 days was the same for patients having (3.04 per 100 patient-years) or not having (3.04 per 100 patient-years) a TOE (p=0.99). There were no differences in the incidence of death (HR 1.19, 95% CI 0.62 to 2.28, p=0.61), cardiovascular hospitalisation (HR 1.02, 95% CI 0.76 to 1.35, p=0.91), stroke/TIA (HR 1.18, 95% CI 0.30 to 4.74, p=0.81) or bleeding-related hospitalisation (HR 1.29, 95% CI 0.66 to 2.52, p=0.45) at 1 year for patients treated with either a NOAC or VKA. Conclusions Cardioversion was a low-risk procedure for patients treated with NOAC, and there were statistically similar rates of stroke/TIA 30 days after cardioversion as for patients treated with VKA. There were no statically significant differences in death, stroke/TIA or major bleeding at 1 year among patients treated with NOAC compared with VKA after cardioversion.

Background: Patients with atrial fibrillation on oral anticoagulation (OAC) undergoing cardiac catheterization face risks for embolic and bleeding events, yet information on strategies to mitigate these risks in contemporary practice is lacking. Methods: We aimed to describe the clinical/procedural characteristics of a contemporary cohort of patients with atrial fibrillation on OAC who underwent cardiac catheterization. Use of bleeding avoidance strategies and bridging therapy were described and outcomes including death, stroke, and major bleeding at 30 days and 1 year were compared by OAC type. Results: Of 13 404 patients in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II Registry from 2013 to 2016, 741 underwent cardiac catheterization (139 with percutaneous coronary intervention) in the setting of OAC. The patients’ median age was 71, 61.8% were male, white (87.2%), had hypertension (83.7%), hyperlipidemia (72.1%), diabetes mellitus (31.6%), and chronic kidney disease (28.2%); 20.2% received warfarin while 79.8% received direct acting oral anticoagulant. One third of patients underwent radial artery access, and bivalirudin was used in 4.6%. Bridging therapy was used more often in patients on warfarin versus direct acting oral anticoagulant (16.7% versus10.0%). OAC was interrupted in 93.8% of patients. Patients on warfarin versus direct acting oral anticoagulant were equally likely to restart OAC (58.0% versus 60.7%), had similar use of antiplatelet therapy (44.0% versus 41.3%) after catheterization, and had similar rates of myocardial infarction and death at 1 year, but higher rates of major bleeding (43.3 versus 12.9 events/100 patient years) and stroke (4.9 versus 1.9 events/100 patient years). Conclusions: In a real-world registry of patients with atrial fibrillation undergoing cardiac catheterization, most cases are elective, performed by femoral access, with interruption of OAC. Bleeding avoidance strategies such as radial artery access and bivalirudin were used infrequently and use of bridging therapy was uncommon. Nearly 40% of patients did not restart OAC postprocedure, exposing patients to risk for stroke. Further research is necessary to optimize the management of patients with atrial fibrillation undergoing cardiac catheterization.