Ventricular rate control in chronic atrial fibrillation during daily activity and programmed exercise: a crossover open-label study of five drug regimens

Comparison between beta-blockers and calcium channel blockers in patients with atrial fibrillation according to renal function

BACKGROUND

Rate control is the most commonly employed first-line management strategy for atrial fibrillation (AF) in patients with chronic kidney disease (CKD). Principal agents used to control heart rate (HR) include beta-blockers (BB) and nondihydropyridine calcium channel blockers (ND-CCB). However, there is a paucity of published studies of the differences between those drugs in CKD patients.

HYPOTHESIS

The present study aimed to investigate the differences, in terms of hospitalizations due to a poor HR control, in patients with AF under a rate-control strategy according to glomerular filtration rate (GFR).

METHODS

The study cohort included 2804 AF patients under rate-control regime (BB or ND-CCB) between January 2014 and April 2020. The end point, determined by competing risk regression, was hospitalizations for AF with rapid ventricular response (RVR), slow ventricular response (SVR), and need for pacemaker.

RESULTS

On multivariate analysis, there were no statistical differences between ND-CCB and BB for subjects with GFR > 60 mL/min/1.73 m2 (subdistribution heart rate [sHR] 0.850, 95% confidence interval [CI]: 0.61-1.19; p = .442) and GFR 30-59 mL/min/1.73 m2 (sHR 1.242, 95% CI: 0.80-1.63; p = .333), while in patients with GFR < 30 mL/min/1.73 m2, ND-CCB therapy was associated with increased hospitalizations due to poor HR control (sHR 4.53, 95% CI: 1.19-17.18; p = .026).

CONCLUSION

In patients with GFR ≥ 30 mL/min/1.73 m2, the choice of ND-CCB or BB had no impact on hospitalizations due to poor HR control, while in GFR < 30 mL/min/1.73 m2, a possible association was detected. The effects of these drugs on GFR < 30 mL/min/1.73 m2 would require further investigation.

Closing the Digitalis Divide: Back to the Basics of Randomized Controlled Trials

PURPOSE

Publishe d decades after several randomized controlled trials (RCT) demonstrating decreased hospitalizations and no effect on all-cause mortality with digoxin use, a series of meta-analyses linking digoxin treatment and mortality have contributed to a narrower application of this medication for the management of heart failure (HF) and atrial fibrillation (AF). Given the conflicting data from the earlier RCTs and more recent meta-analyses, there is a growing polarization among providers for and against the use of digoxin in managing these conditions.

METHODS

To help close this divide, we provide a perspective on the literature with special attention to the quality of both older and more recent studies on this subject.

RESULTS

The data from the highest quality studies we have, RCTs, suggest that digoxin use in patients with HF and/or AF is associated with improvement in several areas of outcomes including functional capacity, symptom management, reduced hospitalizations, fewer deaths due to HF, and treatment of refractory chronic heart failure with rEF, and may even have overall mortality benefit when serum digoxin concentrations are within therapeutic range. These effects are more pronounced in patients with EF < 25% and NYHA Class II-IV and at highest risk for hospitalization.

CONCLUSION

As the risk of confounding factors was minimized by the study design, the likelihood that positive outcomes were identified with digoxin use increased. Clinicians and researchers need further adequately designed and powered RCTs exploring the connection between digoxin therapy and mortality, hospitalizations, and symptom management.

Ivabradine for controlling heart rate in permanent atrial fibrillation: A translational clinical trial

BACKGROUND

Pharmacological options for rate control in atrial fibrillation are scarce. Ivabradine was postulated to reduce the ventricular rate in this setting.

OBJECTIVES

The objectives of this study were to evaluate the mechanism of inhibition of atrioventricular conduction produced by ivabradine and to determine its efficacy and safety in atrial fibrillation.

METHODS

The effects of ivabradine on atrioventricular node and ventricular cells were studied by in vitro whole-cell patch-clamp experiments and mathematical simulation of human action potentials. In parallel, a multicenter, randomized, open-label, phase III clinical trial compared ivabradine with digoxin for uncontrolled permanent atrial fibrillation despite β-blocker or calcium channel blocker treatment.

RESULTS

Ivabradine 1 μM inhibited "funny" current and rapidly activating delayed rectifier potassium channel current by 28.9% and 22.8%, respectively (P < .05). The sodium channel current and L-type calcium channel current were reduced only at 10 μM. Ivabradine slowed the firing frequency of a modeled human atrioventricular node action potential by 10.6% and induced a minimal prolongation of ventricular action potential. Thirty-five (51.5%) patients were randomized to ivabradine and 33 (49.5%) to digoxin. The mean daytime heart rate decreased by 11.6 beats/min (-11.5%) in the ivabradine arm (P = .02) vs 19.6 (-20.6%) in the digoxin arm (P < .001), although the noninferiority margin of efficacy was not met (Z = -1.95; P = .97). The primary safety end point occurred in 3 patients (8.6%) on ivabradine and in 8 (24.2%) on digoxin (P = .10).

CONCLUSION

Ivabradine produced a moderate rate reduction in patients with permanent atrial fibrillation. The inhibition of funny current in the atrioventricular node seems to be the main mechanism responsible for this reduction. Compared with digoxin, ivabradine was less effective, was better tolerated, and had a similar rate of serious adverse events.

DOsing Strategy Effectiveness of Diltiazem in Atrial Fibrillation With Rapid Ventricular Response

STUDY OBJECTIVE

To evaluate the dose-dependent comparative safety and effectiveness between weight-based and alternative dosing strategies for diltiazem in atrial fibrillation with rapid ventricular response.

METHODS

This retrospective cohort study included adult patients presenting to the emergency department (ED) with atrial fibrillation with rapid ventricular response who received treatment with intravenous diltiazem. Groups were retrospectively categorized according to the initial dose: low (<0.1875 mg/kg), weight-based (0.1875 to 0.3125 mg/kg), and high (>0.3125 mg/kg). The primary outcome was rate control (heart rate <100 beats/min) within 30 minutes of treatment.

RESULTS

Of 345 records, 252 were included. Because of scarcity (N=6), outcomes for the high-dose group were not analyzed. By 30 minutes, the weight-based dosing group had more often achieved rate control (weight-based 55%; low 27%; difference 29% [95% confidence interval (CI) 17% to 40%]). Regression analysis identified the weight-based dosing group (odds ratio 3.63, 95% CI 2.06 to 6.39) and initial heart rate of less than 145 beats/min (odds ratio 2.56, 95% CI 1.46 to 4.51) as variables associated with the primary outcome. The weight-based dosing group less often required rescue therapy (weight-based 6%; low 17%; difference -12% [95% CI -20% to -4%]) relative to the low-dose group. Mortality was higher in the low-dose group than in the weight-based dosing group (low 7%; weight-based 1%; difference 6% [95% CI 1% to 11%]).

CONCLUSION

This study shows dose-dependent hemodynamic effects with diltiazem in patients with atrial fibrillation with rapid ventricular response. Weight-based diltiazem (0.25 mg/kg) was associated with greater rate control with no evidence of increased adverse effects. There was no perceived advantage in using lower, alternative doses.

Atrial fibrillation-induced tachycardiomyopathy and heart failure: an underappreciated and elusive condition

Many patients with persistent, chronic, or frequently recurring paroxysmal atrial fibrillation (AF) may develop a tachycardiomyopathy (TCM) with left ventricular (LV) dysfunction and heart failure (HF), which is reversible upon restoration and maintenance of sinus rhythm, when feasible, or via better and tighter ventricular rate (VR) control. Mechanisms involved in producing this leading cause of TCM (AF-TCM) include loss of atrial contraction, irregular heart rate, fast VR, neurohumoral activation, and structural myocardial changes. The most important of all mechanisms relates to optimal VR control, which seems to be an elusive target. Uncontrolled AF may also worsen preexisting LV dysfunction and exacerbate HF symptoms. Data, albeit less robust, also point to deleterious effects of slow VRs on LV function. Thus, a J-shaped relationship between VR and clinical outcome has been suggested, with the optimal VR control hovering at ~ 65 bpm, ranging between 60 and 80 bpm; VRs above and below this range may confer higher morbidity and mortality rates. A convergence of recent guidelines is noted towards a stricter rather than a more lenient VR control with target heart rate < 80 bpm at rest and < 110 bpm during moderate exercise which seems to prevent TCM or improve LV function and exercise capacity and relieve TCM-related symptoms and signs. Of course, restoring and maintaining sinus rhythm is always a most desirable target, when feasible, either with drugs or more likely with ablation. All these issues are herein reviewed, current guidelines are discussed and relevant data are tabulated and pictorially illustrated.

Pharmacokinetics and pharmacodynamics of oral and intravenous metoprolol tartrate in clinically healthy horses

Cardiac drugs with defined pharmacological parameters in horses are limited. The objective of this study was to characterize the pharmacokinetic properties and cardiovascular effects of intravenous and oral metoprolol tartrate (MET) in horses. In a 2-period randomized cross-over design, MET was administered IV (0.04 mg/kg) and PO (6 mg/kg) once to six healthy adult horses. Horses were monitored via continuous telemetry and non-invasive blood pressure (NIBP). Blood samples were serially collected for 72 h post-administration, and concentrations were determined by LC-MS/MS. Pharmacokinetics were modeled using a 3-compartment model and non-linear least squares regression. Median (range) MET concentration was 110 (40.1-197) ng/ml collected 1 min (0.0167 h) after a bolus IV administration. Maximum concentration (C_max ) after PO administration was 2135 (1590-4170) ng/ml at 0.5 (0.25-0.5) hours. Oral bioavailability was 54% (17-100%). Median apparent volume of distribution was 0.39 (0.17-0.58) l/kg, clearance was 12.63 (11.41-18.94) ml/kg/min, and elimination half-life was 21.1 (7.46-34.36) minutes. No clinically relevant effects of IV or PO metoprolol were noted on cardiac rhythm or NIBP. Sweating was the most common side effect. The metoprolol doses used in this study achieve plasma concentrations reported to achieve ß-blockade in humans.

Rate control strategies for atrial fibrillation

Atrial fibrillation (AF) is one of the main cardiac arrhythmias associated with higher risk of cardiovascular morbidity and mortality. AF can cause adverse symptoms and reduced quality of life. One of the strategies for the management of AF is rate control, which can modulate ventricle rate, alleviate adverse associated symptoms and improve the quality of life. As primary management of AF through rate control or rhythm is a topic under debate, the purpose of this review is to explore the rationale for the rate control approach in managing AF by considering the guidelines, recommendations and determinants for the choice of rate control drugs, including beta blockers, digoxin and non- dihydropyridine calcium channel blockers for patients with AF and other comorbidities and atrioventricular nodal ablation and pacing. Despite the limitations of rate control treatment, which may not be effective in preventing disease progression or in reducing symptoms in highly symptomatic patients, it is widely used for almost all patients with atrial fibrillation. Although rate control is one of the first line management of all patient with atrial fibrillation, several issues remain debateable.

Prior beta-blocker treatment improves outcomes in out-of-hospital cardiac arrest patients with non-shockable rhythms

The prognosis of out of cardiac arrest is poor and most cardiac arrest patients suffered from the non-shockable rhythm especially in patients without pre-existing cardiovascular diseases and medication prescription. Beta-blocker (ß-blocker) therapy has been shown to improve outcomes in cardiovascular diseases such as heart failure, ischemia related cardiac, and brain injuries. Therefore, we investigated whether prior ß-blockers use was associated with reduced mortality in patients with cardiac arrest and non-shockable rhythm. We conducted a population-based retrospective cohort study using multivariate propensity score-based regression to control for differences among patients with cardiac arrest. A total of 104,568 adult patients suffering a non-traumatic and non-shockable rhythm cardiac arrest between 2005 and 2011 were identified. ß-blocker prescription at least 30 days prior to the cardiac arrest event was defines as the ß-blockers group. We chose 12.5 mg carvedilol as the cut-off value and defined greater or equal to carvedilol 12.5 mg per day and its equivalent dose as high-dose group. After multivariate propensity score-based logistic regression analysis, patients with prior ß-blockers use were associated with better 1-year survival [adjusted odds ratio (OR), 1.15, 95% confidence interval (CI) 1.01-1.30; P = 0.031]. Compared to non-ß-blocker use group and prior low-dose ß-blockers use group, prior high-dose ß-blockers use group was associated with higher mechanical ventilator wean success rate (adjusted OR 1.19, 95% CI 1.01-1.41, P = 0.042). In conclusion, prior high dose ß-blockers use was associated with a better 1-year survival and higher weaning rate in patients with non-shockable cardiac arrest.

Guidelines for enhanced recovery after cardiac surgery. Consensus document of Spanish Societies of Anesthesia (SEDAR), Cardiovascular Surgery (SECCE) and Perfusionists (AEP)

The ERAS guidelines are intended to identify, disseminate and promote the implementation of the best, scientific evidence-based actions to decrease variability in clinical practice. The implementation of these practices in the global clinical process will promote better outcomes and the shortening of hospital and critical care unit stays, thereby resulting in a reduction in costs and in greater efficiency. After completing a systematic review at each of the points of the perioperative process in cardiac surgery, recommendations have been developed based on the best scientific evidence currently available with the consensus of the scientific societies involved.

Influence of digoxin on mortality in patients with atrial fibrillation: Overview of systematic reviews

Once a routine part of atrial fibrillation (AF) management, digoxin use has declined. Likely hastening this decline are findings from several studies and systematic reviews identifying a potential association between digoxin use and all-cause mortality in AF populations. However, inconsistency exists within some of these studies potentially leading to confusion among clinicians. To critically evaluate the current literature to contextualize the associations between digoxin and mortality risk in patients with AF by performing an overview of systematic reviews. We searched MEDLINE, Cochrane Central Database of Systematic Reviews, and SCOPUS from their earliest date through October 12, 2020, to identify systematic reviews (SRs) that included studies enrolling patients with AF or atrial flutter and evaluated the association between digoxin use and all-cause mortality. We used the AMSTAR 2 tool to assess the risk of bias for each included SR. Results from reviews are qualitatively synthesized. Our search identified 10 SRs that met our inclusion criteria. Of the 41 unique AF studies included in these SRs, 41% were cohort studies, 29% were post hoc analyses of randomized controlled trials (RCTs), 15% were RCTs, and 15% were registry studies. Based on our AMSTAR 2 assessment, the overall confidence in the results of the 10 reviews was rated as "moderate" in three SRs, "low" in three SRs, and "critically low" in the rest. Except for one review, each included SR shows that digoxin use in AF is associated with a 15 to 38% higher risk of all-cause mortality. This association may be greater when AF-only populations are considered compared with a mix of AF and heart failure populations. Serum digoxin concentration (SDC) data were infrequently considered, but available data suggested a greater association between increasing SDC and all-cause mortality. This overview of reviews found general consistency regarding the association between digoxin use and higher all-cause mortality in AF populations. However, heterogeneity exists among and between SRs and an unmet need exists for additional study in a RCT setting with close monitoring and reporting of SDC to better inform clinical practice.

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.

Comparison of Landiolol and Digoxin as an Intravenous Drug for Controlling the Heart Rate in Patients with Atrial Fibrillation and Severely Depressed Left Ventricular Function

Clinical experience with landiolol use in patients with atrial fibrillation (AF) and a severely depressed left ventricular (LV) function is limited. We compared the efficacy and safety of landiolol with that of digoxin as an intravenous drug in controlling the heart rate (HR) during AF associated with a very low LV ejection fraction (LVEF).We retrospectively analyzed 53 patients treated with landiolol (n = 34) or digoxin (n = 19) for AF tachycardias with an LVEF ≤ 25. The landiolol dose was adjusted between 0.5 and 10 μg/kg/minute according to the patient's condition. The response to treatment was defined as a decrease in the HR of ≤ 110/minute, and that decreased by ≥ 20% from baseline.There were no significant differences between the two groups regarding the clinical characteristics. The responder rate to landiolol at 24 hours was significantly higher than that to digoxin (71.0% versus 41.2%; odds ratio: 4.65, 95% confidence interval: 1.47-31.0, P = 0.048). The percent decrease in the HR from baseline at 1, 2, 12, and 24 hours was greater in the landiolol group than in the digoxin group (P < 0.01, P = 0.071, P = 0.036, and P = 0.016, respectively). The systolic blood pressure (SBP) from baseline within 24 hours after administering landiolol was significantly reduced, whereas digoxin did not decrease the SBP over time. Hypotension (< 80 mmHg) occurred in two patients in the landiolol group and 0 in the digoxin group (P = 0.53).Landiolol could be more effective in controlling the AF HR than digoxin even in patients with severely depressed LV function. However, careful hemodynamic monitoring is necessary when administering landiolol.

Pharmacological management of atrial fibrillation in patients with heart failure with reduced ejection fraction: review of current knowledge and future directions

Introduction: Both heart failure with reduced ejection fraction (HFrEF) and atrial fibrillation (AF) independently cause significant morbidity and mortality. The two conditions commonly coexist and AF in the setting of HFrEF is associated with worse mortality, hospitalizations, and quality of life compared to HFrEF without AF. Despite the large burden of these conditions, there is no clear optimal management strategy for when they occur together.Areas covered: This review focuses on the pharmacological management of AF in HFrEF. Studies were identified through PubMed search of relevant keywords. The authors review key clinical trials that have influenced management strategies and guidelines. The authors focus on the classes of drugs used to treat AF for both rate and rhythm control strategies including beta-blockers, digoxin, amiodarone, and dofetilide. Additionally, the authors discuss select non-antiarrhythmic medications that affect AF in HFrEF. The authors highlight the strengths and weakness of the data supporting the use of these medications and suggest future directions.Expert opinion: The pharmacological treatment of AF in HFrEF will need further refinement alongside the emerging role of catheter ablation. Novel HF medications and antiarrhythmics offer new tools to prevent the development of AF, as well as for rate and rhythm control strategies.

The Importance of Heart Rate in Heart Failure and Reduced Ejection Fraction

BACKGROUND

Heart failure with reduced ejection fraction (HFrEF) is a progressive, chronic, and burdensome cardiovascular condition. It is associated with limiting symptoms, such as dyspnea and fatigue; a decline in functional capacity; and premature mortality and hospitalization. In heart failure (HF) management, heart rate is commonly assessed yet frequently overlooked as a modifiable risk factor and a predictor of mortality. An elevated heart rate increases myocardial demand and decreases diastolic filling time. Hospitalized patients with HFrEF who have a heart rate greater than 70 beats per minute at discharge were found to have lower survival rates.

PURPOSE

The aims of this study were to review the association between heart rate and clinical outcome in patients with HF and discuss the contribution of heart rate to HFrEF pathophysiology. Medications currently used to modulate heart rate in patients with HF are also reviewed.

CONCLUSIONS

In patients with HFrEF, an elevated heart rate contributes to HF progression, and it is both a prognostic and modifiable risk factor. Medications such as an evidence-based β-blockers, digoxin, and ivabradine are recommended for modulation of heart rate in patients with HFrEF.

CLINICAL IMPLICATIONS

Nurses play a pivotal role in managing HFrEF and must understand current evidence of the pathophysiology of elevated heart rate, risks, and management strategies. Early recognition of elevated heart rate and application of guideline-directed pharmacologic treatment for patients with HFrEF and an elevated heart rate remains key to improving patient outcomes.

Ivabradine for chronic heart rate control in persistent atrial fibrillation. Design of the BRAKE-AF project

INTRODUCTION AND OBJECTIVES

Ivabradine is an inhibitor of the If channel, the main determinant of the pacemaker function of the sinus node. The drug has been approved for the treatment of angina and heart failure. There is some evidence of its role as an inhibitor of atrial-ventricular node (AVN) conduction. The aim of the BRAKE-AF project is to assess ivabradine use for rate control in atrial fibrillation (AF).

METHODS

A multicenter, randomized, parallel, open-label, noninferiority phase III clinical trial will be conducted to compare ivabradine vs digoxin in 232 patients with uncontrolled permanent AF despite beta-blockers or calcium channel blockers. The primary efficacy endpoint is the reduction in daytime heart rate measured by 24-hour Holter monitoring at 3 months. This clinical trial will be supported by an electrophysiological study of the effect of ivabradine on the action potential of the human AVN. To do this, an experimental model will be used with Chinese hamster ovarium cells transfected with the DNA encoding the expression of the t channels involved in this action potential and recording of the ionic currents with patch clamp techniques.

RESULTS

New data will be obtained on the effect of ivabradine on the human AVN and its safety and efficacy in patients with permanent AF.

CONCLUSIONS

The results of the BRAKE-AF project might allow inclusion of ivabradine within the limited arsenal of drugs currently available for rate control in AF.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov. Identifier: NCT03718273.

Impact of Digitalis Use on Mortality in Japanese Patients With Non-Valvular Atrial Fibrillation - A Subanalysis of the J-RHYTHM Registry

BACKGROUND

Because the influence of digitalis use on the death of patients with non-valvular atrial fibrillation (NVAF) remains controversial, a subanalysis of the J-RHYTHM Registry was performed.Methods and Results:A consecutive series of outpatients with AF from 158 institutions was enrolled and followed for 2 years or until the occurrence of an event. Among 7,406 patients with NVAF, 7,018 (age, 69.7±10.0 years; men, 71.1%) with information on antiarrhythmic drug and digitalis use at baseline were divided into 2 groups based on digitalis use. The influence of digitalis on death was investigated using a propensity score-matching model. In 802 patients treated with digitalis, all-cause death was significantly higher than in 6,216 patients with no digitalis use during the 2-year follow-up period (4.4% vs. 2.4%, unadjusted P<0.001). Digitalis use was significantly associated with all-cause death in the crude model (hazard ratio [HR] 1.85, 95% confidence interval [CI] 1.28-2.68, P=0.001). However, after propensity score-matching, the association was not significant (HR 1.31, 95% CI 0.70-2.46, P=0.405). Older age, male sex, heart failure, coronary artery disease, and lower body mass index were significantly associated with all-cause death in NVAF patients treated with digitalis.

CONCLUSIONS

Digitalis use was not independently associated with all-cause death, and several clinical confounding factors might contribute to increased mortality in NVAF patients treated with digitalis.

Prognosis of heart failure treated with digoxin or with ivabradine: A cohort study in the community

BACKGROUND

Resting heart rate (HR) reduction with ivabradine (IVA) improves outcomes of patients with heart failure and reduced ejection fraction (HFrEF). Nevertheless, the best option to slow HR in patients with HFrEF treated with beta-blockers and a HR >70 bpm is unsettled.

AIMS

To evaluate whether, in patients with HFrEF, commencing therapy with digoxin (CT-DIG) is associated to a worse prognosis than commencing treatment with ivabradine (CT-IVA).

METHODS

Observational study over 10 years on 2364 patients with HFrEF in sinus rhythm and a HR >70 bpm. Main outcomes were mortality, hospitalisations and visits. We analyse the independent relationship of CT-DIG or CT-IVA with the prognosis, stratifying patients for cardiovascular comorbidity, and for other potential confounders (378 patients who CT-DIG vs another 355 patients who CT-IVA vs another 1631 patients non-exposed to IVA or DIG).

RESULTS

During a median follow-up of 57.5 months, 1751 patients (74.1%) died, and 2151 (91.0%) were hospitalised for HF. CT-DIG or CT-IVA was associated with a lower all-cause mortality (DIG: HR = 0.86 [95% CI, 0.82-0.90], and IVA: HR = 0.88 [0.83-0.93]), cardiovascular mortality (DIG: HR = 0.84 [0.80-0.89] and IVA: HR = 0.83 [0.78-0.89]), hospitalisation (DIG: HR = 0.86 [0.83-0.89] and IVA: HR = 0.87 [0.83-0.91]) and 30-day readmission (DIG: HR = 0.84 [0.79-0.90] and IVA: HR = 0.88 [0.79-0.95]), after adjustment for cardiovascular comorbidity, and other potential confounders. These associations with the prognosis of HFrEF did not differ between patients who CT-DIG and those who CT-IVA.

CONCLUSION

Commencing therapy with digoxin or with ivabradine is associated with an improved prognosis of patients with HFrEF.

Digoxin for atrial fibrillation and atrial flutter: A systematic review with meta-analysis and trial sequential analysis of randomised clinical trials

Background

During recent years, systematic reviews of observational studies have compared digoxin to no digoxin in patients with atrial fibrillation or atrial flutter, and the results of these reviews suggested that digoxin seems to increase the risk of all-cause mortality regardless of concomitant heart failure. Our objective was to assess the benefits and harms of digoxin for atrial fibrillation and atrial flutter based on randomized clinical trials.

Methods

We searched CENTRAL, MEDLINE, Embase, LILACS, SCI-Expanded, BIOSIS for eligible trials comparing digoxin versus placebo, no intervention, or other medical interventions in patients with atrial fibrillation or atrial flutter in October 2016. Our primary outcomes were all-cause mortality, serious adverse events, and quality of life. Our secondary outcomes were heart failure, stroke, heart rate control, and conversion to sinus rhythm. We performed both random-effects and fixed-effect meta-analyses and chose the more conservative result as our primary result. We used Trial Sequential Analysis (TSA) to control for random errors. We used GRADE to assess the quality of the body of evidence.

Results

28 trials (n = 2223 participants) were included. All were at high risk of bias and reported only short-term follow-up. When digoxin was compared with all control interventions in one analysis, we found no evidence of a difference on all-cause mortality (risk ratio (RR), 0.82; TSA-adjusted confidence interval (CI), 0.02 to 31.2; I² = 0%); serious adverse events (RR, 1.65; TSA-adjusted CI, 0.24 to 11.5; I² = 0%); quality of life; heart failure (RR, 1.05; TSA-adjusted CI, 0.00 to 1141.8; I² = 51%); and stroke (RR, 2.27; TSA-adjusted CI, 0.00 to 7887.3; I² = 17%). Our analyses on acute heart rate control (within 6 hours of treatment onset) showed firm evidence of digoxin being superior compared with placebo (mean difference (MD), -12.0 beats per minute (bpm); TSA-adjusted CI, -17.2 to -6.76; I² = 0%) and inferior compared with beta blockers (MD, 20.7 bpm; TSA-adjusted CI, 14.2 to 27.2; I² = 0%). Meta-analyses on acute heart rate control showed that digoxin was inferior compared with both calcium antagonists (MD, 21.0 bpm; TSA-adjusted CI, -30.3 to 72.3) and with amiodarone (MD, 14.7 bpm; TSA-adjusted CI, -0.58 to 30.0; I² = 42%), but in both comparisons TSAs showed that we lacked information. Meta-analysis on acute conversion to sinus rhythm showed that digoxin compared with amiodarone reduced the probability of converting atrial fibrillation to sinus rhythm, but TSA showed that we lacked information (RR, 0.54; TSA-adjusted CI, 0.13 to 2.21; I² = 0%).

Conclusions

The clinical effects of digoxin on all-cause mortality, serious adverse events, quality of life, heart failure, and stroke are unclear based on current evidence. Digoxin seems to be superior compared with placebo in reducing the heart rate, but inferior compared with beta blockers. The long-term effect of digoxin is unclear, as no trials reported long-term follow-up. More trials at low risk of bias and low risk of random errors assessing the clinical effects of digoxin are needed.

Systematic review registration

PROSPERO CRD42016052935

Acute Management of Atrial Fibrillation: From Emergency Department to Cardiac Care Unit

The prevalence of atrial fibrillation is increasing rapidly, resulting in more patients presenting for care in the emergency department and in-hospital settings. To reduce morbidity and mortality, and improve patient quality of life, clinicians working in these settings need to be both current and facile in their approach to management of these patients. Frequent updates to guideline recommendations (based on emerging research) make this challenging for practicing physicians. This article reviews the acute management of atrial fibrillation in the emergency and in-hospital settings, including practical approaches to rhythm and rate control, anticoagulation, and special situations, incorporating the most up-to-date guidelines.

The future of atrial fibrillation management: integrated care and stratified therapy

Atrial fibrillation is one of the major cardiovascular health problems: it is a common, chronic condition, affecting 2-3% of the population in Europe and the USA and requiring 1-3% of health-care expenditure as a result of stroke, sudden death, heart failure, unplanned hospital admissions, and other complications. Early diagnosis of atrial fibrillation, ideally before the first complication occurs, remains a challenge, as shown by patients who are only diagnosed with the condition when admitted to hospital for acute cardiac decompensation or stroke. Once diagnosed, atrial fibrillation requires chronic, multidimensional management in five domains (acute management, treatment of underlying and concomitant cardiovascular conditions, stroke prevention therapy, rate control, and rhythm control). The consistent provision of these treatment options to all patients with atrial fibrillation is difficult, despite recent improvements in organisation of care, knowledge about atrial fibrillation, and treatment options. Integrated care models that provide patient-centred care in, or close to, the patient's community while maintaining access to all specialist treatment options, emerge as the best approach to achieve consistent delivery of these chronic treatments to all patients with atrial fibrillation. Ongoing research efforts will establish when to initiate oral anticoagulation in patients with device-detected atrial high-rate episodes, quantify the prognostic effect of early and comprehensive rhythm control therapy, including atrial fibrillation ablation, and delineate optimum methods to reduce bleeding complications in patients treated with anticoagulation. Additionally, research efforts are needed to define different types of atrial fibrillation on the basis of the main causes of atrial fibrillation to pave the way for the clinical development of stratified atrial fibrillation therapy.

A review of rate control in atrial fibrillation, and the rationale and protocol for the RATE-AF trial

BACKGROUND AND OBJECTIVE

Atrial fibrillation (AF) is common and causes impaired quality of life, an increased risk of stroke and death as well as frequent hospital admissions. The majority of patients with AF require control of heart rate. In this article , we summarise the limited evidence from clinical trials that guides prescription, and present the rationale and protocol for a new randomised trial. As rate control has not yet been shown to reduce mortality, there is a clear need to compare the impact of therapy on quality of life, cardiac function and exercise capacity. Such a trial should concentrate on the long-term effects of treatment in the largest proportion of patients with AF, those with symptomatic permanent AF, with the aim of improving patient well-being.

DESIGN AND INTERVENTION

The RAte control Therapy Evaluation in permanent Atrial Fibrillation (RATE-AF) trial will enrol 160 participants with a prospective, randomised, open-label, blinded end point design comparing initial rate control with digoxin or bisoprolol. This will be the first head-to-head randomised trial of digoxin and beta-blockers in AF.

PARTICIPANTS

Recruited patients will be aged ≥60 years with permanent AF and symptoms of breathlessness (equivalent to New York Heart Association class II or above), with few exclusion criteria to maximise generalisability to routine clinical practice.

OUTCOME MEASURES

The primary outcome is patient-reported quality of life, with secondary outcomes including echocardiographic ventricular function, exercise capacity and biomarkers of cellular and clinical response. Follow-up will occur at 6 and 12 months, with feasibility components to inform the design of a future trial powered to detect a difference in hospital admission. The RATE-AF trial will underpin an integrated approach to management including biomarkers, functions and symptoms that will guide future research into optimal, personalised rate control in patients with AF.

ETHICS AND DISSEMINATION

East Midlands-Derby Research Ethics Committee (16/EM/0178); peer-reviewed publications.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT02391337; ISRCTN: 95259705. Pre-results.

Clinical utility of sympathetic blockade in cardiovascular disease management

INTRODUCTION

A dysregulated sympathetic nervous system is a major factor in the development and progression of cardiovascular disease; thus, understanding the mechanism and function of the sympathetic nervous system and appropriately regulating sympathetic activity to treat various cardiovascular diseases are crucial. Areas covered: This review focused on previous studies in managing hypertension, atrial fibrillation, coronary artery disease, heart failure, and perioperative management with sympathetic blockade. We reviewed both pharmacological and non-pharmacological management. Expert commentary: Chronic sympathetic nervous system activation is related to several cardiovascular diseases mediated by various pathways. Advancement in measuring sympathetic activity makes visualizing noninvasively and evaluating the activation level even in single fibers possible. Evidence suggests that sympathetic blockade still has a role in managing hypertension and controlling the heart rate in atrial fibrillation. For ischemic heart disease, beta-adrenergic receptor antagonists have been considered a milestone drug to control symptoms and prevent long-term adverse effects, although its clinical implication has become less potent in the era of successful revascularization. Owing to pathologic involvement of sympathetic nervous system activation in heart failure progression, sympathetic blockade has proved its value in improving the clinical course of patients with heart failure.

Incidence of Atrial Tachyarrhythmias in Patients With Early Repolarization Syndrome

Atrial tachyarrhythmias (ATAs) occur in a significant proportion of Brugada syndrome (BrS) patients and are often an important cause of inappropriate shocks. The aim of this retrospective study was to evaluate the incidence of ATAs and ATA-induced inappropriate shocks in early repolarization syndrome (ERS) patients as compared to BrS patients.We analyzed data from 20 consecutive patients who were diagnosed with ERS and compared them with patients diagnosed with BrS (n = 31). Clinical and ICD interrogation data were collected and analyzed for all events with ICD shocks.Three patients had a history of atrial fibrillation (AF) prior to ICD implantation. One patient had AV reentrant tachycardia and was successfully ablated before ICD implantation. ATAs were newly diagnosed in 4 patients with no prior history of AF. There were no significant differences in gender, age, or left atrial diameter between ATA development. Four (20%) of 20 consecutive patients received inappropriate ICD shocks for ATAs. One suffered from repeat inappropriate shocks triggered by paroxysmal AF and received catheter ablation for AF.ATAs were not infrequent in patients with ERS and seemed to be related to inappropriate ICD therapy. Careful ICD programming is required to reduce ATA-related inappropriate ICD shock in patients with ERS.

2016 Guidelines of the Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology for the management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Both the incidence and prevalence of AF are increasing, and the burden of AF is becoming huge. Many innovative advances have emerged in the past decade for the diagnosis and management of AF, including a new scoring system for the prediction of stroke and bleeding events, the introduction of non-vitamin K antagonist oral anticoagulants and their special benefits in Asians, new rhythm- and rate-control concepts, optimal endpoints of rate control, upstream therapy, life-style modification to prevent AF recurrence, and new ablation techniques. The Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology aimed to update the information and have appointed a jointed writing committee for new AF guidelines. The writing committee members comprehensively reviewed and summarized the literature, and completed the 2016 Guidelines of the Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology for the Management of Atrial Fibrillation. This guideline presents the details of the updated recommendations, along with their background and rationale, focusing on data unique for Asians. The guidelines are not mandatory, and members of the writing committee fully realize that treatment of AF should be individualized. The physician's decision remains most important in AF management.

Recent Advances in the Pharmacological Management of Atrial Fibrillation

Atrial fibrillation (AF) is a highly prevalent cardiac arrhythmia that leads to hospitalizations for complications and adverse events each year. Despite significant improvement in our therapeutic approaches in the past decade, management of AF remains a difficult task. Novel therapies have failed to terminate AF and prevent its recurrence, and patients with AF continue to have thromboembolic complications. With the increasingly aging population and associated conditions, the prevalence of AF is expected to progressively increase, becoming a public health problem. Most patients with AF have multiple comorbidities and are of advanced age, making long-term anticoagulation challenging. This article provides an overview of the current pharmacological therapies for the management of AF, with particular emphasis on the emerging agents.

Atrial fibrillation: review of current treatment strategies

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia in modern clinical practice, with an estimated prevalence of 1.5-2%. The prevalence of AF is expected to double in the next decades, progressing with age and increasingly becoming a global medical challenge. The first-line treatment for AF is often medical treatment with either rate control or anti-arrhythmic agents for rhythm control, in addition to anti-coagulants such as warfarin for stroke prevention in patient at risk. Catheter ablation has emerged as an alternative for AF treatment, which involves myocardial tissue lesions to disrupt the underlying triggers and substrates for AF. Surgical approaches have also been developed for treatment of AF, particularly for patients requiring concomitant cardiac surgery or those refractory to medical and catheter ablation treatments. Since the introduction of the Cox-Maze III, this procedure has evolved into several modern variations, including the use of alternative energy sources (Cox-Maze IV) such as radiofrequency, cryo-energy and microwave, as well as minimally invasive thoracoscopic epicardial approaches. Another recently introduced technique is the hybrid ablation approach, where in a single setting both epicardial thoracoscopic ablation lesions and endocardial catheter ablation lesions are performed by the cardiothoracic surgeon and cardiologist. There remains controversy surrounding the optimal approach for AF ablation, energy sources, and lesion sets employed. The goal of this article is review the history, classifications, pathophysiology and current treatment options for AF.

Rate control in atrial fibrillation

Control of the heart rate (rate control) is central to atrial fibrillation management, even for patients who ultimately require control of the rhythm. We review heart rate control in patients with atrial fibrillation, including the rationale for the intervention, patient selection, and the treatments available. The choice of rate control depends on the symptoms and clinical characteristics of the patient, but for all patients with atrial fibrillation, rate control is part of the management. Choice of drugs is patient-dependent. β blockers, alone or in combination with digoxin, or non-dihydropyridine calcium-channel blockers (not in heart failure) effectively lower the heart rate. Digoxin is least effective, but a reasonable choice for physically inactive patients aged 80 years or older, in whom other treatments are ineffective or are contraindicated, and as an additional drug to other rate-controlling drugs, especially in heart failure when instituted cautiously. Atrioventricular node ablation with pacemaker insertion for rate control should be used as an approach of last resort but is also an option early in the management of patients with atrial fibrillation treated with cardiac resynchronisation therapy. However, catheter ablation of atrial fibrillation should be considered before atrioventricular node ablation. Although rate control is a top priority and one of the first management issues for all patients with atrial fibrillation, many issues remain.

Atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac rhythm disorder, and increases in prevalence with increasing age and the number of cardiovascular comorbidities. AF is characterized by a rapid and irregular heartbeat that can be asymptomatic or lead to symptoms such as palpitations, dyspnoea and dizziness. The condition can also be associated with serious complications, including an increased risk of stroke. Important recent developments in the clinical epidemiology and management of AF have informed our approach to this arrhythmia. This Primer provides a comprehensive overview of AF, including its epidemiology, mechanisms and pathophysiology, diagnosis, screening, prevention and management. Management strategies, including stroke prevention, rate control and rhythm control, are considered. We also address quality of life issues and provide an outlook on future developments and ongoing clinical trials in managing this common arrhythmia.

Atrial fibrillation management: evaluating rate vs rhythm control

Atrial fibrillation (AF) is an increasing global issue leading to increased hospitalizations, adverse health related events and mortality. This review focuses on the management of atrial fibrillation, in particular in the past decade, comparing two major strategies, rate or rhythm control. We evaluate the evidence for each strategy, pharmacological options and the increasing utilization of invasive techniques, in particular catheter ablation and use of implantable cardiac pacing devices. Pharmacological comparative trials evaluating both strategies have shown rate control being non-inferior to rhythm control for clinical outcomes of mortality and other cardiovascular events (including stroke). Catheter ablation techniques, involving radiofrequency ablation and recently cryoablation, have shown promising results in particular with paroxysmal AF. However, persistent AF provides ongoing challenges and will be a particular focus of continued research.

Arrhythmia-Induced Cardiomyopathies: Mechanisms, Recognition, and Management

Arrhythmia-induced cardiomyopathy (AIC) is a potentially reversible condition in which left ventricular dysfunction is induced or mediated by atrial or ventricular arrhythmias. Cellular and extracellular changes in response to the culprit arrhythmia have been identified, but specific pathophysiological mechanisms remain unclear. Early recognition of AIC and prompt treatment of the culprit arrhythmia using pharmacological or ablative techniques result in symptom resolution and recovery of ventricular function. Although cardiomyopathy in response to an arrhythmia may take months to years to develop, recurrent arrhythmia can result in rapid decline in ventricular function with development of heart failure, suggesting residual ultrastructural abnormalities. Reports of sudden death in patients with normalized left ventricular ejection fraction cast doubt on the complete reversibility of this condition. Several aspects of AIC, including specific pathophysiological mechanisms, predisposing factors, optimal therapeutic strategies to prevent ultrastructural changes, and long-term risk of sudden death remain unresolved and need further research.

Atrial fibrillation: mechanisms, therapeutics, and future directions

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia, affecting 1% to 2% of the general population. It is characterized by rapid and disorganized atrial activation leading to impaired atrial function, which can be diagnosed on an EKG by lack of a P-wave and irregular QRS complexes. AF is associated with increased morbidity and mortality and is a risk factor for embolic stroke and worsening heart failure. Current research on AF support and explore the hypothesis that initiation and maintenance of AF require pathophysiological remodeling of the atria, either specifically as in lone AF or secondary to other heart disease as in heart failure-associated AF. Remodeling in AF can be grouped into three categories that include: (i) electrical remodeling, which includes modulation of L-type Ca(2+) current, various K(+) currents and gap junction function; (ii) structural remodeling, which includes changes in tissues properties, size, and ultrastructure; and (iii) autonomic remodeling, including altered sympathovagal activity and hyperinnervation. Electrical, structural, and autonomic remodeling all contribute to creating an AF-prone substrate which is able to produce AF-associated electrical phenomena including a rapidly firing focus, complex multiple reentrant circuit or rotors. Although various remodeling events occur in AF, current AF therapies focus on ventricular rate and rhythm control strategies using pharmacotherapy and surgical interventions. Recent progress in the field has started to focus on the underlying substrate that drives and maintains AF (termed upstream therapies); however, much work is needed in this area. Here, we review current knowledge of AF mechanisms, therapies, and new areas of investigation.

Beta-blockers or Digoxin for Atrial Fibrillation and Heart Failure?

In patients with atrial fibrillation (AF) and heart failure (HF) with or without systolic dysfunction, either rhythm control or rate control is an acceptable primary therapeutic option. If a rate control strategy is chosen, treatment with a beta-blocker is almost always required to achieve rate control. Adequate ventricular rate control is usually a resting rate of less than 100 beats per minute, but lower resting rates may be appropriate. Non-dihydropyridine calcium channel blockers are often contraindicated when AF is associated with HF with systolic dysfunction. There have been recent debates on a possible reduced efficacy of beta-blockers as well as safety issues with digoxin when treating HF patients with AF. The benefit of beta-blockers on survival may be lower in patients with HF with reduced ejection fraction when AF is present. Digoxin does not improve survival but may help to obtain satisfactory rate control in combination with a beta-blocker. Digoxin may be useful in the presence of hypotension or an absolute contraindication to beta-blocker treatment.

Automatically finding relevant citations for clinical guideline development

OBJECTIVE

Literature database search is a crucial step in the development of clinical practice guidelines and systematic reviews. In the age of information technology, the process of literature search is still conducted manually, therefore it is costly, slow and subject to human errors. In this research, we sought to improve the traditional search approach using innovative query expansion and citation ranking approaches.

METHODS

We developed a citation retrieval system composed of query expansion and citation ranking methods. The methods are unsupervised and easily integrated over the PubMed search engine. To validate the system, we developed a gold standard consisting of citations that were systematically searched and screened to support the development of cardiovascular clinical practice guidelines. The expansion and ranking methods were evaluated separately and compared with baseline approaches.

RESULTS

Compared with the baseline PubMed expansion, the query expansion algorithm improved recall (80.2% vs. 51.5%) with small loss on precision (0.4% vs. 0.6%). The algorithm could find all citations used to support a larger number of guideline recommendations than the baseline approach (64.5% vs. 37.2%, p<0.001). In addition, the citation ranking approach performed better than PubMed's "most recent" ranking (average precision +6.5%, recall@k +21.1%, p<0.001), PubMed's rank by "relevance" (average precision +6.1%, recall@k +14.8%, p<0.001), and the machine learning classifier that identifies scientifically sound studies from MEDLINE citations (average precision +4.9%, recall@k +4.2%, p<0.001).

CONCLUSIONS

Our unsupervised query expansion and ranking techniques are more flexible and effective than PubMed's default search engine behavior and the machine learning classifier. Automated citation finding is promising to augment the traditional literature search.

Atrial Fibrillation

Atrial fibrillation (AF) is a supraventricular tachyarrhythmia that results from the chaotic depolarization of atrial tissue. AF is the most common sustained cardiac dysrhythmia and the most common dysrhythmia diagnosed in US emergency departments. All patients with AF must have their cardioembolic risk assessed, even if sinus rhythm is restored. Novel oral anticoagulants may be considered instead of vitamin K antagonists for anticoagulation in patients with nonvalvular AF.

Management of tachycardia

Tachycardia, conventionally, but arbitrarily, defined as an atrial and/or ventricular rate of >100 beats per minute, is encountered commonly and can be physiological or pathological in origin. Various adverse consequences from tachycardia have been recognized, and an important one is the association between persistent tachycardia and cardiomyopathy. In this article, we provide an up-to-date review on the etiology of tachycardia, management strategies, and the prognosis of patients presenting with tachycardia and cardiomyopathy.