The pharmaceutical pipeline for atrial fibrillation

Cardiovascular outcomes in patients with atrial fibrillation concomitantly treated with antiarrhythmic drugs and non-vitamin k antagonist oral anticoagulants

AIMS

Limited data compared antiarrhythmic drugs (AADs) with concomitant non-vitamin K antagonist oral anticoagulants in atrial fibrillation patients, hence the aim of the study.

METHODS AND RESULTS

National health insurance database were retrieved during 2012-17 for study. We excluded patients not taking AADs, bradycardia, heart block, heart failure admission, mitral stenosis, prosthetic valve, incomplete demographic data, and follow-up <3 months. Outcomes were compared in Protocol 1, dronedarone vs. non-dronedarone; Protocol 2, dronedarone vs. amiodarone; and Protocol 3, dronedarone vs. propafenone. Outcomes were acute myocardial infarction (AMI), ischaemic stroke/systemic embolism, intracranial haemorrhage (ICH), major bleeding, cardiovascular death, all-cause mortality, and major adverse cardiovascular event (MACE) (including AMI, ischaemic stroke, and cardiovascular death). In Protocol 1, 2298 dronedarone users and 6984 non-dronedarone users (amiodarone = 4844; propafenone = 1914; flecainide = 75; sotalol = 61) were analysed. Dronedarone was associated with lower ICH (HR = 0.61, 95% CI = 0.38-0.99, P = 0.0436), cardiovascular death (HR = 0.24, 95% CI = 0.16-0.37, P < 0.0001), all-cause mortality (HR = 0.33, 95% CI = 0.27-0.42, P < 0.0001), and MACE (HR = 0.56, 95% CI = 0.45-0.70, P < 0.0001). In Protocol 2, 2231 dronedarone users and 6693 amiodarone users were analysed. Dronedarone was associated with significantly lower ICH (HR = 0.53, 95%=CI 0.33-0.84, P = 0.0078), cardiovascular death (HR = 0.20, 95% CI = 0.13-0.31, P < 0.0001), all-cause mortality (HR 0.27, 95% CI 0.22-0.34, P < 0.0001), and MACE (HR = 0.53, 95% CI = 0.43-0.66, P < 0.0001), compared with amiodarone. In Protocol 3, 812 dronedarone users and 2436 propafenone users were analysed. There were no differences between two drugs for primary and secondary outcomes.

CONCLUSION

The use of dronedarone with NOACs was associated with cardiovascular benefits in an Asian population, compared with non-dronedarone AADs and amiodarone.

Rhythm control without catheter ablation may have benefits beyond stroke prevention in rivaroxaban-treated non-permanent atrial fibrillation

The current treatment paradigm for atrial fibrillation (AF) prioritizes rate control over rhythm control; however, rhythm control has shown benefits over other AF strategies. This study compares the outcomes of rivaroxaban with and without concomitant antiarrhythmic drugs (AADs), using propensity score matching to correct for statistical effects of baseline discrepancies. This multi-center retrospective study included 1,477 patients with non-permanent AF who took rivaroxaban for at least one month between 2011 and 2016 and had not received catheter ablation. Concomitant AAD use was compared against clinical outcome endpoints for effectiveness, safety, and major adverse cardiac events (MACE). Associations with concomitant AAD use were evaluated using multivariate Cox proportional hazard analyses. Patients were divided into two matched groups: rivaroxaban alone (n = 739) and with concomitant AADs (n = 738). The cumulative incidences of safety (p = 0.308), effectiveness (p = 0.583), and MACE (p = 0.754) were similar between the two groups, and multivariate analysis showed no significant differences. The new thromboembolism and all-cause death rates were higher in rivaroxaban alone (2.7% vs 0.8%, p = 0.005; and 10% vs. 6.9%, p = 0.032, respectively). The heart failure readmission rate was higher in the concomitant-AAD group (8.4% vs. 13.3%, p = 0.003). The concomitant use of rivaroxaban with AADs appears to be well-tolerated, with lower rates of thromboembolism and all-cause death, but is associated with more occurrences of congestive heart failure.

Mechanisms Underlying Antiarrhythmic Properties of Cardioprotective Agents Impacting Inflammation and Oxidative Stress

The prevention of cardiac life-threatening ventricular fibrillation and stroke-provoking atrial fibrillation remains a serious global clinical issue, with ongoing need for novel approaches. Numerous experimental and clinical studies suggest that oxidative stress and inflammation are deleterious to cardiovascular health, and can increase heart susceptibility to arrhythmias. It is quite interesting, however, that various cardio-protective compounds with antiarrhythmic properties are potent anti-oxidative and anti-inflammatory agents. These most likely target the pro-arrhythmia primary mechanisms. This review and literature-based analysis presents a realistic view of antiarrhythmic efficacy and the molecular mechanisms of current pharmaceuticals in clinical use. These include the sodium-glucose cotransporter-2 inhibitors used in diabetes treatment, statins in dyslipidemia and naturally protective omega-3 fatty acids. This approach supports the hypothesis that prevention or attenuation of oxidative and inflammatory stress can abolish pro-arrhythmic factors and the development of an arrhythmia substrate. This could prove a powerful tool of reducing cardiac arrhythmia burden.

Safety and Effectiveness of Rivaroxaban in Combination with Various Antiarrhythmic Drugs in Patients with Non-Permanent Atrial Fibrillation

INTRODUCTION

Rivaroxaban reduces the risk of thromboembolism in atrial fibrillation (AF) patients, who often also receive antiarrhythmic drugs (AADs) to maintain sinus rhythm. Current guidelines contraindicate concomitant use of rivaroxaban with the popular AAD dronedarone, despite little data demonstrating interactions with AADs. This study investigates the outcomes of concomitant rivaroxaban and AAD drug use in a real-world cohort.

METHODS

This retrospective study included 1777 non-permanent AF patients taking rivaroxaban for ≥ 1 month between 2011 and 2016 from a multicenter cohort in Taiwan, and compared concomitant AAD use against clinical outcome endpoints for safety, effectiveness, and major adverse cardiac events (MACE). Multivariate Cox proportional hazard analyses were used to evaluate the association between concomitant AAD use and outcomes.

RESULTS

Patients were divided into rivaroxaban alone (n = 1205) and with concomitant amiodarone (n = 177), dronedarone (n = 231), or propafenone (n = 164) groups. The proportion of patients using rivaroxaban 10 mg was highest in the concomitant dronedarone group: rivaroxaban alone, 53.6%; with amiodarone, 57.6%; with dronedarone, 77.1%; and with propafenone, 46.3% (p < 0.001). The cumulative incidences of safety (p = 0.892), effectiveness (p = 0.336), and MACE (p = 0.674) were similar between the four groups; however, there were significantly fewer new systemic thromboembolisms in the dronedarone group: rivaroxaban alone, 2.5%; with amiodarone, 0.6%; with dronedarone, 0%; and with propafenone, 1.2% (p = 0.029). The all-cause death rate was also lowest in the dronedarone group: rivaroxaban alone, 9.0%; with amiodarone, 9.6%; with dronedarone, 3.0%; and with propafenone: 6.1% (p = 0.013). After covariate adjustment, there were no differences in the safety, effectiveness, and MACE endpoints between patients receiving or not receiving AADs.

CONCLUSION

Concomitant use of rivaroxaban with AADs appears to be well tolerated, warranting further investigation into the apparent benefits of a reduced dose of rivaroxaban combined with dronedarone.

Meta-Analysis Comparing Catheter-Guided Ablation Versus Conventional Medical Therapy for Patients With Atrial Fibrillation and Heart Failure With Reduced Ejection Fraction

The prognostic benefit of catheter ablation (CA) for atrial fibrillation in the setting of heart failure (HF) with reduced ejection fraction (EF) is unclear. A systematic search of medical literature was limited to randomized controlled trials. The primary outcome was all-cause mortality, and secondary outcomes were HF hospitalizations, stroke, left ventricular EF improvement, change in 6-minute walk test, and change in Minnesota living with HF questionnaire (Δ MLHFQ). Random effects risk ratios (RR) were calculated for categorical outcomes and standardized mean differences (SMD) for continuous ones, using Der-Simonian and Liard model. A total of 775 ambulatory patients from 6 trials were included. The mean EF was 31% with a mean New York Heart Association classification class 2.5. At a mean follow-up of 26 months, CA was associated with lower incidences of all-cause mortality (RR 0.50, 95% confidence intervals [CI] 0.34 to 0.74, I² = 0%, p <0.0001), and HF hospitalizations (RR 0.58, 95% CI 0.41 to 0.81, p = 0.002, I² = 0%), with similar incidences of stroke. Left ventricular EF improvement (SMD = 2.58, 95% CI 0.88 to 4.27), and change in Minnesota living with heart failure HF questionnaire (SMD = -0.40, 95% CI -0.65 to -0.14) were also in favor of CA, with no difference noted in change in 6-minute walk test. The incidence of all reported procedural complications (including major and minor) was 7.3%. In conclusion, CA of atrial fibrillation appears to be associated with improved survival and HF hospitalizations compared with medical therapy, with evidence of low ablation-related complications.

Ablation Versus Amiodarone for Treatment of Persistent Atrial Fibrillation in Patients With Congestive Heart Failure and an Implanted Device

Background—

Whether catheter ablation (CA) is superior to amiodarone (AMIO) for the treatment of persistent atrial fibrillation (AF) in patients with heart failure is unknown.

Methods and Results—

This was an open-label, randomized, parallel-group, multicenter study. Patients with persistent AF, dual-chamber implantable cardioverter defibrillator or cardiac resynchronization therapy defibrillator, New York Heart Association II to III, and left ventricular ejection fraction <40% within the past 6 months were randomly assigned (1:1 ratio) to undergo CA for AF (group 1, n=102) or receive AMIO (group 2, n=101). Recurrence of AF was the primary end point. All-cause mortality and unplanned hospitalization were the secondary end points. Patients were followed up for a minimum of 24 months. At the end of follow-up, 71 (70%; 95% confidence interval, 60%–78%) patients in group 1 were recurrence free after an average of 1.4±0.6 procedures in comparison with 34 (34%; 95% confidence interval, 25%–44%) in group 2 (log-rank P <0.001). The success rate of CA in the different centers after a single procedure ranged from 29% to 61%. After adjusting for covariates in the multivariable model, AMIO therapy was found to be significantly more likely to fail (hazard ratio, 2.5; 95% confidence interval, 1.5–4.3; P <0.001) than CA. Over the 2-year follow-up, the unplanned hospitalization rate was (32 [31%] in group 1 and 58 [57%] in group 2; P <0.001), showing 45% relative risk reduction (relative risk, 0.55; 95% confidence interval, 0.39–0.76). A significantly lower mortality was observed in CA (8 [8%] versus AMIO (18 [18%]; P =0.037).

Conclusions—

This multicenter randomized study shows that CA of AF is superior to AMIO in achieving freedom from AF at long-term follow-up and reducing unplanned hospitalization and mortality in patients with heart failure and persistent AF.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00729911.

In vitro photoacoustic visualization of myocardial ablation lesions

BACKGROUND

Radiofrequency (RF) ablation to treat atrial arrhythmia is limited by the inability to reliably assess lesion durability and transmurality.

OBJECTIVE

The purpose of this study was to determine the feasibility of photoacoustic characterization of myocardial ablation lesions in vitro. In this study, we investigated the feasibility of combined ultrasound (US) and spectroscopic photoacoustic imaging to visualize RF ablation lesions in three dimensions (3D) based on unique differences in the optical absorption spectra between normal and ablated myocardial tissue.

METHODS

Tissue samples were excised from the ventricles of fresh porcine hearts. Lesions were generated using an RF catheter ablation system using 20 to 30 W of power applied for 40 to 60 seconds. Ablated samples were imaged in the near-infrared regime (740-780 nm) using a combined PA/US imaging system. Measured PA spectra were correlated to the absorption spectra of deoxyhemoglobin and ablated tissue to produce a tissue characterization map (TCM) identifying 3D lesion location and extent. Tissue samples were stained and photographed for gross pathology. TCM and gross pathology images were coregistered to assess TCM accuracy.

RESULTS

TCM reliably characterized ablated and non-ablated tissue up to depths of 3 mm. TCM also assessed lesion position and extent with submillimeter accuracy in multiple dimensions. Segmented TCMs achieved >69% agreement with gross pathology.

CONCLUSION

The study results suggest that spectroscopic photoacoustic imaging has the potential to accurately assess RF ablation lesion size and position with submillimeter precision and may be well suited to guide transcatheter RF atrial ablation in clinical practice.

Examining the safety of amiodarone

INTRODUCTION

Amiodarone is the most widely used antiarrhythmic agent, with demonstrated effectiveness against all the spectrum of cardiac tachyarrhythmias. The risk of adverse effects acts as a limiting factor to its utilization especially in the long term. This article systematically reviews the published evidence on amiodarone versus placebo to examine its safety as an antiarrhythmic drug.

AREAS COVERED

Authors collected data on adverse effects reported in 49 randomized placebo-controlled trials with amiodarone. Adverse effects were classified according to the organ/system involved. Pooled estimates of the number needed to treat (NNT) and to harm (NNH) versus placebo were calculated.

EXPERT OPINION

Amiodarone is effective for both the acute conversion of atrial fibrillation (AF) (11 trials, NNT = 4 at 24 h; p = 0.003) and the prevention of postoperative AF (18 trials, NNT = 8; p < 0.001), although with an increased risk of bradycardia, hypotension, nausea or phlebitis (pooled NNH = 4; p < 0.001). Amiodarone administration for the maintenance of sinus rhythm has a favorable net clinical benefit (pooled NNT = 3; p < 0.001 versus pooled NNH for either thyroid toxicity, gastrointestinal discomfort, skin toxicity or eye toxicity = 11; p < 0.001). Treatment with amiodarone for the prophylaxis of sudden cardiac death has less favorable net clinical benefit (15 trials, NNT = 38; p < 0.001 versus NNH for either thyroid toxicity, hepatic toxicity, pulmonary toxicity or bradycardia = 14; p < 0.001). Amiodarone treatment in this setting should be used in only selected cases.