Non-pharmacologic autonomic neuromodulation for treatment of heart failure: A systematic review and meta-analysis of randomized controlled trials

Treatment strategies that modulate autonomic tone through interventional and device-based therapies have been studied as an adjunct to pharmacological treatment of heart failure with reduced ejection fraction (HFrEF). The main objective of this study was to perform a meta-analysis of randomized controlled trials which evaluated the efficacy of device-based autonomic modulation for treatment of HFrEF. All randomized-controlled trials testing autonomic neuromodulation device therapy in HFrEF were included in this trial-level analysis. Autonomic neuromodulation techniques included vagal nerve stimulation (VNS), baroreflex activation (BRA), spinal cord stimulator (SCS), and renal denervation (RD). The prespecified primary endpoints included mean change and 95% confidence intervals (CI) of left ventricular ejection fraction (LVEF), NT pro-B-type natriuretic peptide (NT-proBNP), and quality of life (QOL) measures including 6-minute hall walk distance (6-MHWD), and Minnesota Living with Heart Failure Questionnaire (MLHFQ). New York Heart Association (NYHA) functional class improvement was reported as odds ratios and 95% CI of improvement by at least 1 functional class. Eight studies were identified that included 1037 participants (2 VNS, 2 BRA, 1 SCS, and 3 RD trials). This included 6 open-label, 1 single-blind, and 1 sham-controlled, double-blind study. The mean age (±SD) was 61 (±9.3) years. The mean follow-up time was 7.9 months. Twenty percent of the total patients were female, and the mean BMI (±SD) was 29.86 (±4.12). Autonomic neuromodulation device therapy showed a statistically significant improvement in LVEF (4.02%; 95% CI 0.24,7.79), NT-proBNP (-219.80 pg/ml; 95% CI -386.56, -53.03), NYHA functional class (OR 2.32; 95% CI 1.76, 3.07), 6-MHWD (48.39 m; 95% CI 35.49, 61.30), and MLHFQ (-12.20; 95% CI -19.24, -5.16) compared to control. In patients with HFrEF, the use of autonomic neuromodulation device therapy is associated with improvement in LVEF, reduction in NT-proBNP, and improvement in patient-centered QOL outcomes in mostly small open-label trials. Large, double-blind, sham-controlled trials designed to detect differences in hard cardiovascular outcomes are needed before widespread use and adoption of autonomic neuromodulation device therapies in HFrEF.

Pulmonary vein isolation with adjunctive left atrial ganglionic plexus ablation for treatment of atrial fibrillation: a meta-analysis of randomized controlled trials

BACKGROUND

Adjunctive ganglionic plexus (GP) ablation may increase the efficacy of pulmonary vein isolation (PVI) for treatment of atrial fibrillation (AF). Prior meta-analyses examining PVI with adjunctive GP ablation have included non-randomized trials and have included trials evaluating thorascopic epicardial ablation. The objective of this study is to perform a meta-analysis of randomized controlled trials (RCTs) comparing endocardial catheter-based PVI to PVI with adjunctive GP ablation.

METHODS

Summary odds ratio (OR) and 95% confidence intervals (CIs) were calculated. Heterogeneity was assessed with I² values. Sub-group analysis was performed comparing arrhythmia recurrence between patients with paroxysmal versus persistent AF at trial baseline. Meta-regressions were performed with mean left atrial diameter and left ventricular ejection fraction at trial baseline as the moderator variables.

RESULTS

Five RCTs were identified including 814 patients: 406 PVI + GP ablation and 408 PVI alone. The mean age of participants was 56.5 years and 74.7% were male. Four of these trials evaluated catheter-based endocardial ablation for a total of 574 patients: 289 PVI + GP ablation and 285 PVI alone. The odds of arrhythmia recurrence in patients undergoing adjunctive GP ablation with PVI compared with PVI alone were a reduced: odds ratio (OR) 0.58, 95% confidence interval (CI) 0.41-0.82, I² = 40.2%. In the subgroup analysis, the odds of arrhythmia recurrence with adjunctive GP ablation were reduced in those with paroxysmal AF (OR 0.396, 95% CI 0.23-0.69, I² = 0%). A non-significant trend to reduced arrhythmia recurrence was also observed in those with persistent AF (OR 0.726, 95% CI 0.475-1.112, I² = 0%). When performing the meta-regression, increased left atrial diameter was associated with decreased treatment effect of adjunctive GP ablation (R² index = 1.0, I² = 0%).

CONCLUSIONS

The addition of GP ablation to PVI was associated with reduced arrhythmia recurrence. Adjunctive GP ablation was more effective in paroxysmal AF and in patients with smaller atria. Larger RCTs are needed to confirm the efficacy of GP + PVI ablation.

Dosing of Direct Oral Anticoagulants in Patients with Moderate Chronic Kidney Disease in US Clinical Practice: Results from the Outcomes Registry for Better Informed Treatment of AF (ORBIT-AF II)

INTRODUCTION

Direct oral anticoagulants (DOACs) have partial renal clearance and generally require dosage adjustments based on renal function. While current US and European guidance recommends dose adjustments in patients with moderate chronic kidney disease (CKD), it is unclear how often this is done appropriately in routine clinical practice.

METHODS

We examined rates of appropriate and inappropriate dosing in patients with atrial fibrillation (AF) and moderate CKD, as determined by creatinine clearance (CrCl) of 30-50 mL/min calculated with the Cockcroft-Gault formula. Descriptive statistics were used to describe the rate of appropriate and inappropriate dosing as well as event rates.

RESULTS

Among 1134 patients (8.5% of the overall ORBIT-AF II registry) with AF and CrCl 30-50 mL/min, the median age was 82 (25th, 75th percentile: 78, 86), 38% were male, and the median CHA₂DS₂VASC score was 4 (25th, 75th percentile: 4, 5). At baseline, more than one-third (34%) of patients with moderate CKD were inappropriately dosed with DOACs. When evaluating the specific prescribed doses in those with moderate CKD, 15% (N = 170/1134) were underdosed, 66% (743/1134) were appropriately dosed, and 20% (N = 221/1134) were overdosed. There were no significant differences in comorbid medical conditions between patients with moderate CKD who were appropriately and inappropriately dosed with a DOAC.

CONCLUSION

In routine clinical practice, prescribing of DOACs in patients with AF with moderate CKD is often inconsistent with drug labeling, with up to one-third of patients being inappropriately dosed.

A Comparison of Rate Control Agents for the Treatment of Atrial Fibrillation: Follow-Up Investigation of the AFFIRM Study

There are limited data from randomized controlled trials comparing rate control agents in atrial fibrillation. Patient-level data from the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial was used to compare outcomes in patients randomized to the rate control arm who were treated with a single rate control agent at baseline. The rate control agents used were beta-blockers, non-dihydropyridine calcium channel blockers, and digoxin. The independent variable for this analysis was the initial study drug used and the dependent variables were time to first hospitalization and time to death from any cause. We analyzed 1,144 out of 2,027 participants assigned to the rate control group who were on a single rate control agent at the start of the trial. There were 485 (42.5%) participants in the beta-blocker group, 344 (30%) in the calcium channel blocker group, and 315 (27.5%) in the digoxin group. All hospitalization and all-cause mortality occurred in 55.9% and 12.5% of those in the beta-blocker group, 58.4% and 16.7% in the calcium channel blocker group, and 55.2% and 21.1% in the digoxin group, respectively. After adjustment for differences in baseline characteristics, there were no significant differences in time to hospitalization or death for any group. In the AFFIRM trial, the initial rate control drug used was not associated with statistically significant differences in time to hospitalization or death after controlling for differences in baseline characteristics. There is limited data at present to guide the selection of rate control agents in patients with atrial fibrillation.

Assessment of OMT-28, a synthetic analog of omega-3 epoxyeicosanoids, in patients with persistent atrial fibrillation: Rationale and design of the PROMISE-AF phase II study

We designed a placebo controlled, double-blind, randomized, dose-finding phase II study on OMT-28 in the maintenance of sinus rhythm after electrical cardioversion (DCC) in patients with persistent atrial fibrillation (PROMISE-AF). OMT-28 is a first-in-class, synthetic analog of 17,18-epoxyeicosatetetraenoic acid, a bioactive lipid mediator generated by cytochrome P450 enzymes from the omega-3 fatty acid eicosapentaenoic acid. OMT-28 improves Ca²⁺-handling and mitochondrial function in cardiomyocytes and reduces pro-inflammatory signaling. This unique mode of action may provide a novel approach to target key mechanism contributing to AF pathophysiology. In a recent phase I study, OMT-28 was safe and well tolerated and showed favorable pharmacokinetics. The PROMISE-AF study (NCT03906799) is designed to assess the efficacy (primary objective), safety, and population pharmacokinetics (secondary objectives) of three different doses of OMT-28, administered once daily, versus placebo until the end of the follow-up period. Recruitment started in March 2019 and the study will include a total of 120 patients. The primary efficacy endpoint is the AF burden (% time with any AF), evaluated over a 13-week treatment period after DCC. AF burden is calculated based on continuous ECG monitoring using an insertable cardiac monitor (ICM). The primary efficacy analysis will be conducted on the modified intention-to-treat (mITT) population, whereas the safety analysis will be done on the safety population. Although ICMs have been used in other interventional studies to assess arrhythmia, PROMISE-AF will be the first study to assess antiarrhythmic efficacy and safety of a novel rhythm-stabilizing drug after DCC by using ICMs.

Patterns of oral anticoagulation use with cardioversion in clinical practice

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.

Factors Associated With Large Improvements in Health-Related Quality of Life in Patients With Atrial Fibrillation: Results From ORBIT-AF

BACKGROUND

Atrial fibrillation (AF) adversely impacts health-related quality of life (hrQoL). While some patients demonstrate improvements in hrQoL, the factors associated with large improvements in hrQoL are not well described.

METHODS

We assessed factors associated with a 1-year increase in the Atrial Fibrillation Effect on Quality-of-Life score of 1 SD (≥18 points; 3× clinically important difference), among outpatients in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation I registry.

RESULTS

Overall, 28% (181/636) of patients had such a hrQoL improvement. Compared with patients not showing large hrQoL improvement, they were of similar age (median 73 versus 74, P=0.3), equally likely to be female (44% versus 48%, P=0.3), but more likely to have newly diagnosed AF at baseline (18% versus 8%; P=0.0004), prior antiarrhythmic drug use (52% versus 40%, P=0.005), baseline antiarrhythmic drug use (34.8% versus 26.8%, P=0.045), and more likely to undergo AF-related procedures during follow-up (AF ablation: 6.6% versus 2.0%, P=0.003; cardioversion: 12.2% versus 5.9%, P=0.008). In multivariable analysis, a history of alcohol abuse (adjusted OR, 2.41; P=0.01) and increased baseline diastolic blood pressure (adjusted OR, 1.23 per 10-point increase and >65 mm Hg; P=0.04) were associated with large improvements in hrQoL at 1 year, whereas patients with prior stroke/transient ischemic attack, chronic obstructive pulmonary disease, and peripheral arterial disease were less likely to improve (P<0.05 for each).

CONCLUSIONS

In this national registry of patients with AF, potentially treatable AF risk factors are associated with large hrQoL improvement, whereas less reversible conditions appeared negatively associated with hrQoL improvement. Understanding which patients are most likely to have large hrQoL improvement may facilitate targeting interventions for high-value care that optimizes patient-reported outcomes in AF. Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01165710.

Outcomes and Anticoagulation Use After Catheter Ablation for Atrial Fibrillation

Background:

Studies evaluating the effects of atrial fibrillation (AF) catheter ablation versus antiarrhythmic therapy on outcomes have shown mixed results. In addition, guidelines recommend continuing oral anticoagulation (OAC) after ablation for those at risk of stroke, but real-world data are lacking.

Methods:

We evaluated outcomes including death, myocardial infarction, stroke or systemic embolism, intracranial bleeding, major bleeding, and hospitalization in patients undergoing AF ablation compared with a propensity score matched cohort of patients treated with anti-arrhythmic medications only in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation registries. Cox proportional hazards regression was performed to evaluate the association between AF ablation and outcomes. We then evaluated patterns of treatment with OAC among AF ablation patients.

Results:

Among 21 595 patients, 1190 (6%) underwent de novo AF ablation. Our propensity score-matched cohort included 1087 patients who underwent AF ablation matched 1:1 with 1087 patients treated with antiarrhythmic medications only. There were no significant differences in the risk of all-cause and cardiovascular death, and most other major adverse cardiovascular and neurological events. AF catheter ablation was associated with an increased risk of all-cause hospitalization during follow-up (hazard ratio, 1.24 [95% CI, 1.05–1.46]), particularly in the first 3 months (the standard blanking period) after the procedure. Among those who underwent AF ablation with a CHA 2 DS 2 VASc score ≥2 for men and ≥3 for women, 23% had OAC discontinued after ablation. Among those who discontinued OAC, the median time to discontinuation was 6.2 months.

Conclusions:

In this large US national registry, we found no difference in adjusted rates of cardiovascular or all-cause death between patients treated with AF catheter ablation and antiarrhythmic medications only. Notably, discontinuation of OAC after ablation remains relatively common despite guideline recommendations for continued stroke prevention therapy in patients at risk of stroke.

Pharmacotherapy for Atrial Fibrillation in Patients With Chronic Kidney Disease: Insights From ORBIT-AF

Background Chronic kidney disease ( CKD ) is a common comorbidity in patients with atrial fibrillation. The presence of CKD complicates drug selection for stroke prevention and rhythm control. Methods and Results Patients enrolled in ORBIT AF (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation) with baseline renal function and follow-up data were included (N=9019). CKD was defined as an estimated creatinine clearance <60 mL /min. Patient characteristics were compared by CKD status, and Cox proportional hazards modeling was used to examine the association between oral anticoagulant ( OAC ) use and outcomes and antiarrhythmic drug use and outcomes stratified by CKD stages. At enrollment, 3490 (39%) patients had an estimated creatinine clearance <60 mL /min. Patients with CKD were older and had higher CHA ₂ DS ₂ VAS c and Anticoagulant and Risk Factors in Atrial Fibrillation (ATRIA) scores. A rhythm control strategy was selected less frequently in patients with CKD , while OAC use was lower among Stage IV and V CKD patients. After adjustment, no significant interaction was noted for OAC and CKD on all-cause mortality ( P=0.5442) or cardiovascular death ( P=0.1233), although a trend for increased major bleeding ( P=0.0608) and stroke, systemic embolism or transient ischemic attack ( P=0.0671) was observed. No interaction was noted for antiarrhythmic drug use and CKD status on all-cause mortality ( P=0.9706), or stroke, systemic embolism or transient ischemic attack ( P=0.4218). Conclusions Patients with atrial fibrillation and CKD are less likely to be treated with rhythm control. Patients with advanced CKD are less likely to receive OAC . Finally, outcomes with OAC in patients with advanced CKD may be materially different with higher rates of both bleeding and stroke.

Association of sex and atrial fibrillation therapies with patient-reported outcomes

OBJECTIVES

Women report higher atrial fibrillation (AF) symptom severity and receive less AF therapies than their male counterparts. It is understudied if differences in AF therapies received explains sex differences in AF symptom severity. We investigate the impact of sex and AF therapies on patient-reported outcomes.

METHODS

Participants were recruited (n=953) across four academic medical centres with an AF diagnosis and age ≥18 years. Patient-reported outcomes (AF symptom severity, AF-related quality of life, functional status and emotional status) were determined by biannual surveys. We performed multiple linear regressions on propensity-matched cohorts to determine the association of AF therapies and sex on patient-reported outcomes.

RESULTS

Our study population (n=953) was 65% male (n=616), 93% white (n=890) and 72 (±10) years old. Individuals receiving rate control therapy reported comparatively lower AF-related quality of life (-7.22, 95% CI -11.51 to -2.92) and poorer functional status (-3.69, 95% CI -5.27 to -2.12). Individuals receiving rhythm control strategies did not report significantly different patient-reported outcomes. Women were more likely to report poorer functional status (-2.63, 95% CI -3.86 to -1.40) and poorer AF-related quality of life, higher anxiety (2.33, 95% CI 1.07 to 3.59), higher symptoms of depression (1.48, 95% CI 0.31 to 2.65) and AF symptom severity (0.29, 95% CI 0.07 to 0.52).

CONCLUSIONS

Female sex was associated with comparatively poorer AF symptom severity and quality of life, and this association remained after accounting for AF therapies received. Receiving rate control medication alone was associated with comparatively poorer AF-related quality of life and functional status.

Treatment of Atrial Fibrillation and Concordance With the American Heart Association/American College of Cardiology/Heart Rhythm Society Guidelines: Findings From ORBIT-AF (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation)

BACKGROUND

It is unclear how frequently patients with atrial fibrillation receive guideline-concordant (GC) care and whether guideline concordance is associated with improved outcomes.

METHODS AND RESULTS

Using data from ORBIT-AF (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation), we determined how frequently patients received care that was concordant with 11 recommendations from the 2014 American Heart Association/American College of Cardiology/Heart Rhythm Society atrial fibrillation guidelines pertaining to antithrombotic therapy, rate control, and antiarrhythmic medications. We also analyzed the association between GC care and clinical outcomes at both the patient level and center level. A total of 9570 patients were included. The median age was 75 years (interquartile range, 67-82), and the median CHA₂DS₂-VASc score was 4 (interquartile range, 3-5). A total of 5977 patients (62.5%) received care that was concordant with all guideline recommendations for which they were eligible. Rates of GC care were higher in patients treated by providers with greater specialization in arrhythmias (60.0%, 62.4%, and 67.0% for primary care physicians, cardiologists, and electrophysiologists, respectively; P<0.001). During a median of 30 months of follow-up, patients treated with GC care had a higher risk of bleeding hospitalization (hazard ratio=1.21; P=0.021) but a similar risk of death, stroke, major bleeding, and all-cause hospitalization.

CONCLUSIONS

Over a third of patients with atrial fibrillation in this large outpatient registry received care that differed in some respect from guideline recommendations. There was no apparent association between GC care and improved risk-adjusted outcomes.

Off-Label Dosing of Non-Vitamin K Antagonist Oral Anticoagulants and Adverse Outcomes: The ORBIT-AF II Registry

BACKGROUND

Although non-vitamin K antagonist oral anticoagulants (NOACs) do not require frequent laboratory monitoring, each compound requires dose adjustments on the basis of certain clinical criteria.

OBJECTIVES

This study assessed the frequency of off-label NOAC doses among AF patients and the associations between off-label dose therapy and clinical outcomes in community practice.

METHODS

We evaluated 5,738 patients treated with a NOAC at 242 ORBIT-AF II (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation phase II) sites. NOAC doses were classified as either underdosed or overdosed, consistent with Food and Drug Administration labeling. Longitudinal outcomes (median follow-up: 0.99 years) included stroke or systemic embolism, myocardial infarction, major bleeding (International Society of Thrombosis and Haemostasis criteria), cause-specific hospitalization, and all-cause mortality.

RESULTS

Overall, 541 NOAC-treated patients (9.4%) were underdosed, 197 were overdosed (3.4%), and 5,000 were dosed according to U.S. labeling (87%). Compared with patients receiving the recommended dose, those who were receiving off-label doses were older (median: 79 and 80 years of age vs. 70 years of age, respectively; p < 0.0001), more likely female (48% and 67% vs. 40%, respectively; p < 0.0001), less likely to be treated by an electrophysiologist (18% and 19% vs. 27%, respectively; p < 0.0001), and had higher CHA₂DS₂-VASc scores (96% and 97% ≥2 vs. 86%, respectively; p < 0.0001) and higher ORBIT bleeding scores (25% and 31% >4 vs. 11%, respectively; p < 0.0001). After dose adjustment, NOAC overdosing was associated with increased all-cause mortality compared with recommended doses (adjusted hazard ratio: 1.91; 95% confidence interval [CI]: 1.02 to 3.60; p = 0.04). Underdosing was associated with increased cardiovascular hospitalization (adjusted hazard ratio: 1.26; 95% CI: 1.07 to 1.50; p = 0.007).

CONCLUSIONS

A significant minority (almost 1 in 8) of U.S. patients in the community received NOAC doses inconsistent with labeling. NOAC over- and underdosing are associated with increased risk for adverse events. (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II [ORBIT-AF II]; NCT01701817).

Oral anticoagulation management in patients with atrial fibrillation undergoing cardiac implantable electronic device implantation

Background

Oral anticoagulation (OAC) therapy is associated with increased periprocedural risks after cardiac implantable electronic device (CIED) implantation. Patterns of anticoagulation management involving non–vitamin K antagonist oral anticoagulants (NOACs) have not been characterized.

Hypothesis

Anticoagulation strategies and outcomes differ by anticoagulant type in patients undergoing CIED implantation.

Methods

Using the nationwide Outcomes Registry for Better Informed Treatment of Atrial Fibrillation, we assessed how atrial fibrillation (AF) patients undergoing CIED implantation were cared for and their subsequent outcomes. Outcomes were compared by oral anticoagulant therapy (none, warfarin, or NOAC) as well as by anticoagulation interruption status.

Results

Among 9129 AF patients, 416 (5%) underwent CIED implantation during a median follow‐up of 30 months (interquartile range, 24–36). Of these, 60 (14%) had implantation on a NOAC. Relative to warfarin therapy, those on a NOAC were younger (70.5 years [range, 65–77.5 years] vs 77 years [range, 70–82 years]), had less valvular heart disease (15.0% vs 31.3%), higher creatinine clearance (67.3 [range, 59.7–99.0] vs 65.8 [range, 50.0–91.6]), were more likely to have persistent AF (26.7% vs 22.9%), and use concomitant aspirin (51.7% vs 35.2%). OAC therapy was commonly interrupted for CIED in 64% (n = 183 of 284) of warfarin patients and 65% (n = 39 of 60) of NOAC patients. Many interrupted patients received intravenous bridging anticoagulation: 33/183 (18%) interrupted warfarin and 4/39 (10%) interrupted NOAC patients. Thirty‐day periprocedure bleeding and stroke adverse events were infrequent.

Conclusions

Management of anticoagulation among AF patients undergoing CIED implantation is highly variable, with OAC being interrupted in more than half of both warfarin‐ and NOAC‐treated patients. Bleeding and stroke events were infrequent in both warfarin and NOAC‐treated patients.

Increased Heart Rate Is Associated With Higher Mortality in Patients With Atrial Fibrillation (AF): Results From the Outcomes Registry for Better Informed Treatment of AF (ORBIT-AF)

BACKGROUND

Most patients with atrial fibrillation (AF) require rate control; however, the optimal target heart rate remains under debate. We aimed to assess rate control and subsequent outcomes among patients with permanent AF.

METHODS AND RESULTS

We studied 2812 US outpatients with permanent AF in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation. Resting heart rate was measured longitudinally and used as a time-dependent covariate in multivariable Cox models of all-cause and cause-specific mortality during a median follow-up of 24 months. At baseline, 7.4% (n=207) had resting heart rate <60 beats per minute (bpm), 62% (n=1755) 60 to 79 bpm, 29% (n=817) 80 to 109 bpm, and 1.2% (n=33) ≥110 bpm. Groups did not differ by age, previous cerebrovascular disease, heart failure status, CHA2DS2-VASc scores, renal function, or left ventricular function. There were significant differences in race (P=0.001), sinus node dysfunction (P=0.004), and treatment with calcium-channel blockers (P=0.006) and anticoagulation (P=0.009). In analyses of continuous heart rates, lower heart rate ≤65 bpm was associated with higher all-cause mortality (adjusted hazard ratio [HR], 1.15 per 5-bpm decrease; 95% CI, 1.01 to 1.32; P=0.04). Similarly, increasing heart rate >65 bpm was associated with higher all-cause mortality (adjusted HR, 1.10 per 5-bpm increase; 95% CI, 1.05 to 1.15; P<0.0001). This relationship was consistent across endpoints and in a broader sensitivity analysis of permanent and nonpermanent AF patients.

CONCLUSIONS

Among patients with permanent AF, there is a J-shaped relationship between heart rate and mortality. These data support current guideline recommendations, and clinical trials are warranted to determine optimal rate control.

CLINICAL TRIAL REGISTRATION

URL: http://clinicaltrials.gov/. Unique identifier: NCT01165710.

Abstract 301: Healthcare Costs Following Stroke and Major Bleeding Events in Nonvalvular Atrial Fibrillation Patients

Objectives: We sought to determine the impact of stroke and major bleeding excluding intracranial hemorrhage (MB) events on healthcare costs in a real-world nonvalvular atrial fibrillation (NVAF) population.

Methods: Healthcare claims data from U.S. commercial and Medicare health plans were used to identify beneficiaries with NVAF during 2008-2012. Patients were classified into cohorts according to event type (No event, Stroke only, MB only, or Stroke plus MB). All-cause total healthcare costs and inpatient costs related to stroke and MB were calculated during 1-year period following the index date (date of initial event or first qualifying AF claim for No event group). Inpatient hospitalizations related to events were identified using ICD-9-CM diagnosis codes. Costs were standardized to 2012 US dollars.

Results: Of the 40,654 patients included in the study, 28% had events (8.9% Stroke only, 14.5% MB only, and 4.7% Stroke plus MB). Relative to the No event cohort, all-cause unadjusted per-patient per-month (PPPM) total costs were $4,669 higher for Stroke only and $4,160 for MB only. For Stroke plus MB patients, unadjusted all-cause PPPM total costs were $6,322 higher compared to the No event cohort. Among Stroke only and MB only patients, the economic burden of hospitalizations related to MB (57% of total costs) was similar to Stroke only (63% of total costs). Hospitalizations related to stroke or MB accounted for 65% of total costs for Stroke plus MB.

Conclusions: NVAF patients who have a stroke or MB event incur higher healthcare costs relative to patients without events. Interventions preventing stroke or MB events have the potential to reduce the healthcare burden associated NVAF.

Drivers of hospitalization for patients with atrial fibrillation: Results from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF)

BACKGROUND

Atrial fibrillation (AF) is the most common cardiac dysrhythmia and contributes significantly to health care expenditures. We sought to assess the frequency and predictors of hospitalization in patients with AF.

METHODS

The ORBIT-AF registry is a prospective, observational study of outpatients with AF enrolled from June 29, 2010, to August 9, 2011. The current analysis included 9,484 participants with 1-year follow-up. Multivariable, logistic regression was used to identify baseline characteristics that were associated with first cause-specific hospitalization.

RESULTS

Overall, 31% of patients with AF studied (n = 2,963) had 1 or more hospitalizations per year and 10% (n = 983) had 2 or more. The most common hospitalization cause was cardiovascular (20 per 100 patient-years vs 3.3 bleeding vs 17 noncardiovascular, nonbleeding). Compared with those not hospitalized, hospitalized patients were more likely to have concomitant heart failure (42% vs 28%, P < .0001), higher mean CHADS2 (1 point for congestive heart failure, hypertension, age ≥75, or diabetes; 2 points for prior stroke or transient ischemic attack) scores (2.5 vs 2.2, P < .0001), and more symptoms (baseline European Heart Rhythm Association class severe symptoms 18% vs 13%, P < .0001). In multivariable analysis, heart failure (adjusted hazard ratio [HR] 1.57 for New York Heart Association III/IV vs none, P < .0001), heart rate at baseline (adjusted HR 1.11 per 10-beats/min increase >66, P < .0001), and AF symptom class (adjusted HR 1.37 for European Heart Rhythm Association severe vs none, P < .0001) were the major predictors of incident hospitalization.

CONCLUSIONS

Hospitalization is common in outpatients with AF and is independently predicted by heart failure and AF symptoms. Improved symptom control, rate control, and comorbid condition management should be evaluated as strategies to reduce health care use in these patients.

Rate versus rhythm control for management of atrial fibrillation in clinical practice: results from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) registry

BACKGROUND

All patients with atrial fibrillation (AF) require optimization of their ventricular rate. Factors leading to use of additional rhythm control in clinical practice have not been thoroughly defined.

METHODS

The ORBIT-AF registry enrolled patients with AF from a broad range of practice settings and collected data on rate versus rhythm control, as indicated by the treating physician. Multivariable logistic regression analysis was performed to identify factors associated with each strategy.

RESULTS

Of 10,061 patients enrolled, 6,859 (68%) were managed with rate only control versus 3,202 (32%) with rhythm control. Patients managed with rate control were significantly older and more likely to have hypertension, heart failure, prior stroke, and gastrointestinal bleeds. They also had fewer AF-related symptoms (41% with no symptoms vs 31% for rhythm control). Systemic anticoagulation was prescribed for 5,448 (79%) rate-control patients versus 2,219 (69%) rhythm-control patients (P < .0001). After multivariable adjustment, patients with higher symptom scores (severe symptoms vs. none, OR 1.62, 95% CI 1.41-1.87) and those referred to electrophysiologists (OR 1.64, 95% CI 1.45-1.85) were more likely to be managed with a rhythm control strategy.

CONCLUSIONS

In this outpatient registry of US clinical practice, the majority of patients with AF were managed with rate control alone. Patients with more symptoms and who were treated by an electrophysiologist were more likely to receive rhythm-control therapies. A significant proportion of AF patients, regardless of treatment strategy, were not treated with anticoagulation for thromboembolism prophylaxis.

Dronedarone for the treatment of atrial fibrillation and atrial flutter: approval and efficacy

Dronedarone, a new Class III antiarrhythmic agent, has now been approved by the US Food and Drug Administration for use in patients with atrial fibrillation or atrial flutter. Approval came in March 2009 due to the positive results of the ATHENA trial showing significant reductions in all-cause mortality and cardiovascular hospitalization with dronedarone use. A post hoc analysis of the ATHENA data also suggested a decrease in stroke risk with this agent. However, due to safety concerns in the heart failure population in the earlier ANDROMEDA trial, dronedarone is not recommended for patients with an ejection fraction <35% and recent decompensated heart failure. Dronedarone is an amiodarone analog with multichannel blocking electrophysiologic properties similar to those of amiodarone, but several structural differences. Dronedarone’s lack of the iodine moiety reduces its potential for thyroid and pulmonary toxicity. Preliminary data from the DIONYSOS trial, and an indirect meta-analysis comparing amiodarone with dronedarone, showed amiodarone to be more effective in maintaining sinus rhythm, while dronedarone was associated with fewer adverse effects resulting in early termination of the drug. Dronedarone is the first antiarrhythmic drug for the treatment of atrial fibrillation and atrial flutter shown to reduce cardiovascular hospitalizations. In patients with structural heart disease who have an ejection fraction >35% and no recent decompensated heart failure, dronedarone should be considered earlier than amiodarone in the treatment algorithm.

The impact of new and emerging clinical data on treatment strategies for atrial fibrillation

INTRODUCTION

The Atrial Fibrillation (AF) Exchange Group, an international multidisciplinary group concerned with the management of AF, was convened to review recent advances in the field and the potential impact on treatment strategies.

METHODS

Issues discussed included epidemiology and the impact of the rising incidence of AF on health care systems, developments in pharmacological and surgical interventions in the management of arrhythmias and thromboprophylaxis, the potential to affect treatment strategies, and barriers to implementing them.

RESULTS

The incidence of AF and the associated burden on health care systems are increasing with aging populations, prevalence of comorbidities and more effective treatment of cardiovascular diseases. Advances in available medical treatments, in particular dronedarone and dabigatran, with other products in development, offer the possibility of changes in treatment paradigms and a greater emphasis on reducing hospitalizations and improvement in long-term outcomes instead of a symptom/safety-driven approach in which the priority is symptom suppression without provoking drug toxicity. Developments in catheter ablation techniques may mean that, in experienced centers, ablation may be offered as first-line treatment in selected patient populations. Barriers to optimal treatment include underdiagnosis, lack of recognition as a serious condition and as a risk factor for stroke, limited access to care, inadequate implementation of guidelines, and poor adherence to treatment.

CONCLUSIONS

The focus of the management of AF may be changing as a consequence of new treatments based on the outcome improvements they offer. However, the benefits will not be fully realized if guidelines and guidance are not observed in routine clinical practice.

Gender differences in arrhythmias

Electrocardiographic and electrophysiologic differences between men and women have long been noted. Women have a higher intrinsic heart rate than men, along with a longer corrected QT interval and a shorter sinus nodal recovery time. The incidence of and risk factors for a variety of arrhythmias differ between men and women. Atrioventricular nodal reentry tachycardia has a 2:1 female-to-male predominance, while accessory pathways are twice as frequent in men. Although atrial fibrillation is more prevalent in men of all age groups, the absolute numbers of men and women with atrial fibrillation are equal, and the associated morbidity and mortality experienced by women with atrial fibrillation appear to be worse. Women have a lower incidence of sudden cardiac death, and female survivors of sudden cardiac death have a lower frequency of spontaneous or inducible ventricular tachycardia. On the other hand, drug-induced torsade de pointes and symptomatic long QT syndrome have a female predominance. Therefore, greater caution should be used when prescribing QT-prolonging drugs in women. The incidence of arrhythmias is increased during pregnancy, and management of pregnant patients poses a significant challenge. The mechanisms of these gender differences are unclear but may be related to hormonal effects and the shorter QT interval in adult males. Pharmacologic and nonpharmacologic therapies are usually equally efficacious, but the risks of pharmacologic therapy are different in men and women. Atrial fibrillation may be more difficult to treat in women.

Arrhythmogenic right ventricular dysplasia: cardiomyopathy current opinions on diagnostic and therapeutic aspects

Right Ventricular Dysplasia constitutes a genetic cardiomyopathy characterized by fibrous-adipose substitution of the right and rarely of the left ventricular myocardium. This disorder is associated with ventricular arrhythmias ranging from frequent ventricular ectopic beats, nonsustained and sustained ventricular tachycardia of left bundle branch morphology and sudden death. Therefore, the syndrome has been labelled Arrhythmogenic RVD Cardiomyopathy. Diagnostic criteria, preliminary genetic data, and clinical manifestations are summarized and critical addressed, using data from the literature and from our own experience. The most important aspects of the ECG in this syndrome are reviewed and stressed with particular attention to initial versus advanced clinical subsets. The typical anatomical abnormalities and biopsy or pathology material are presented.

Practical guidelines for clinicians who treat patients with amiodarone. Practice Guidelines Subcommittee, North American Society of Pacing and Electrophysiology

Amiodarone has become an important drug for the treatment of supraventricular and ventricular arrhythmias, in short-term inpatient and outpatient settings. It may also have a role in affecting outcome in patients at high risk for arrhythmic events and sudden death; its place among available therapies is being established in clinical trials.

Biventricular pacing in patients with congestive heart failure: two prospective randomized trials. The VIGOR CHF and VENTAK CHF Investigators

Epidemiologic studies suggest that 20-30% of patients diagnosed with symptomatic congestive heart failure (CHF) have intraventricular conduction disorders characterized by a discoordinate contraction pattern and wide QRS. Biventricular pacing is an emerging therapy allowing simultaneous electrical stimulation of the right and left ventricles with the use of an implantable pacing system. The aim of this article is to describe 2 prospective randomized multicenter trials examining the effects of biventricular pacing on functional capacity, quality of life, and hemodynamic status in patients with dilated cardiomyopathy and intraventricular delay. The VIGOR CHF Trial is designed to assess functional and symptomatic improvement in heart failure patients with biventricular pacing and without a concomitant indication for conventional bradycardia pacemaker therapy. To assess for potential placebo effects, patients are randomized to receive either biventricular pacemaker therapy or no pacing therapy for the first 6 weeks, after which both groups receive pacing therapy. The VENTAK CHF trial uses an implantable cardioverter defibrillator system (ICD) designed to provide chronic biventricular pacing therapy in addition to treating ventricular tachyarrhythmias. All patients receive conventional ICD and CHF therapy throughout the study and are randomized in a 2-period crossover design to receive either no pacing or biventricular pacing for 3-month intervals. Patient enrollment in both studies is ongoing, with a closed analysis. The unique designs of these trials provide the opportunity to study this therapy in high-risk patients who have been optimally treated for heart failure.

Treatment of atrioventricular node reentrant tachycardia with encainide: reversal of drug effect with isoproterenol

To determine the efficacy of encainide in the treatment of atrioventricular (AV) node reentrant tachycardia, Holter electrocardiographic (ECG) monitoring, exercise treadmill testing and programmed electrical stimulation were performed in 16 patients while they were taking no medication and after steady state levels were reached during treatment with encainide (75 to 200 mg/day; mean 117 +/- 47). In addition, to study the possible reversal of drug effects by sympathetic stimulation, AV node conduction and tachycardia induction were reassessed during isoproterenol infusion (1 to 3 micrograms/min), a dose calculated to increase the rest heart rate by 25 +/- 10%. Sustained AV node reentrant tachycardia could be initiated in all 16 patients in the control state, in 2 patients after encainide and in 10 patients during isoproterenol infusion. The shortest mean atrial paced cycle length sustaining 1:1 AV conduction was 358 +/- 57 ms during the control study, which increased to 409 +/- 59 ms with encainide (p less than 0.01 versus control) and decreased to 313 +/- 31 ms during isoproterenol infusion (p less than 0.01 versus control and encainide). The shortest mean ventricular paced cycle length with 1:1 ventriculoatrial conduction was 337 +/- 56 ms in the control study, 551 + 124 ms with encainide infusion (p less than 0.01 versus control) and 354 +/- 72 ms during isoproterenol infusion in the encainide-loaded state (p less than 0.01 versus both control and encainide). During a mean follow-up period of 19 +/- 10 months, significant clinical recurrences occurred in 4 of the 10 patients in whom tachycardia could still be initiated with encainide (with or without isoproterenol).(ABSTRACT TRUNCATED AT 250 WORDS)