Adverse effects of low dose amiodarone: a meta-analysis

Anti-arrhythmic therapy in patients with non-ischemic cardiomyopathy

Implantable cardiac defibrillators (ICD) are the foundation of therapy for the prevention of sudden cardiac death. While ICDs prevent SCD, they do not prevent the occurrence of ventricular arrhythmias which are usually symptomatic. Though catheter ablation has been successful in substrate modification of ventricular tachycardia in patients with ischemic cardiomyopathy, there is much less evidence to support its use in non-ischemic cardiomyopathy. Therefore, anti-arrhythmic drugs (AADs) are an essential adjunctive therapy for secondary prevention of ventricular arrhythmias in patients with non-ischemic cardiomyopathy. In patients with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM), the prevalence of ventricular arrhythmias correlates with the volume of scar as characterized by late gadolinium enhancement. Beta-blockers forms the cornerstone of treatment to prevent ventricular arrhythmias in both HCM and DCM. Disopyramide is an important therapeutic option in HCM as it provides both negative inotropy which reduces obstruction as well as lass I anti-arrhythmic action. In DCM sotalol, through is combined beta-blocking and class III AD effects, significantly reduces the burden of ventricular arrhythmias. Though amiodarone is efficacious in the prevention of ventricular arrhythmias in both HCM and DCM, its use is limited by its side-effects profile. Evidence for AAD therapy for arrhythmogenic right ventricular dysplasia (ARVD) is limited by its low prevalence and lack of studies. ICDs have been shown to reduce SCD regardless of whether patients are receiving AAD therapy.

Acute breathlessness with frank hemoptysis following catheter ablation for atrial fibrillation, a cause not so obvious

All clinicians prescribing amiodarone require knowledge of the challenging diagnosis and management of amiodarone-induced pulmonary toxicity (APT), which is potentially fatal. APT should be considered early in all patients presenting with new respiratory symptoms and concurrent amiodarone therapy. Drug cessation and corticosteroid therapy can be highly effective once recognized.

Does Sotalol Still Have a Role in the Management of Arrhythmias?

Despite proven effectiveness in treating tachyarrhythmias, sotalol is proarrhythmic and can cause torsades de pointes. Given the emergence of studies that show no benefit from rhythm control strategies in managing atrial fibrillation, as well as the introduction of nonpharmacological approaches to treating arrhythmias, we felt it necessary to ascertain if there was any role for sotalol given its side effects. Review of the literature regarding sotalol use in the prevention and treatment of supraventricular and ventricular tachyarrhythmias seems to show that more effective and safer agents and nonpharmacological alternatives are currently available. However, sotalol still seems to be useful in preventing supraventricular tachyarrhythmias postcardiac surgery and in reverting hemodynamically stable sustained ventricular tachycardias in the setting of coronary artery disease. Its role in the prevention of tachyarrhythmias in the setting of arrhythmogenic right ventricular cardiomyopathy requires further investigation.

Gastrointestinal and liver diseases and atrial fibrillation: a review of the literature

Atrial fibrillation (AF) is the most common arrhythmia worldwide and is associated with significant morbidity and mortality. A number of risk factors have been associated with AF, though few studies have explored the association between gastrointestinal and liver diseases and AF. Additionally, AF and treatment for AF may predispose to gastrointestinal and liver diseases. We review the current literature on the bidirectional associations between gastrointestinal and liver diseases and AF. We highlight the gaps in knowledge and areas requiring future investigation.

Atrial Fibrillation Ablation Should Be First-line Therapy in Patients with Heart Failure Reduced Ejection Fraction

Catheter ablation for atrial fibrillation in patients with heart failure with reduced ejection fraction is associated with improvement in patient-centered outcomes, such as mortality, heart failure readmission, and atrial fibrillation recurrence, compared with standard medical therapy with or without device therapy. The evidence is not as robust in patients with atrial fibrillation and heart failure with preserved ejection fraction.

[Clinical aspects of treatment with amiodarone]

Amiodarone has multiple and complex electrophysiological effects that render it a very effective antiarrhythmic drug for the treatment of both, supraventricular and ventricular arrhythmias. Proarrhythmic effects of amiodarone in patients with structural heart disease are rare. However, extracardiac adverse effects occurring in association with amiodarone treatment are frequent and feared. These adverse effects have usually been related to total amiodarone exposure (i. e., dose and duration of treatment). Parallel to a more frequent use of lower amiodarone maintenance doses (100-200 mg/day), the incidence of severe unwanted extracardiac side effects has decreased. High-dose maintenance regiments (daily dose ≥300 mg) are usually obsolete. This paper discusses recommendations regarding the monitoring of cardiac and extracardiac side effects of amiodarone. They need to be regarded by physicians using amiodarone to ensure long-term safety of amiodarone therapy.

Adherence to Monitoring Guidelines of Amiodarone Adverse Reactions

BACKGROUND

Amiodarone treatment frequently causes adverse reactions. Clinical guidelines warrant a comprehensive assessment prior to chronic treatment with amiodarone and repeated monitoring for the appearance of adverse reactions.

OBJECTIVE

To evaluate adherence to these guidelines.

METHODS

A retrospective chart review of electronic medical records of adult patients treated with oral amiodarone for at least 12 months.

RESULTS

One hundred patient records were analyzed; 97% of patients were evaluated for thyroid and liver functions prior to treatment. Liver functions were properly monitored every 6 months in 96% of patients and thyroid function in only 59%. Most (84%) patients completed a chest X-ray before treatment; only 2% completed a respiratory function test. None have performed a chest X-ray annually. Sixty-four percent of the patients were examined by an ophthalmologist prior to treatment; periodic ophthalmic surveillance was not consistent. Neurological and dermatological evaluations were not recorded for any of the patients, unless symptoms appeared. Only 50% were adherent to annual cardiac reassessment.

CONCLUSIONS

Adherence to recommended clinical guidelines for monitoring amiodarone adverse reactions is poor. Interventions to improve compliance with these guidelines are needed.

Prevention of Recurrent Ventricular Tachycardia in Patients With Implantable Cardioverter Defibrillators-A Network Meta-analysis

BACKGROUND

The optimal management for the prevention of recurrent ventricular tachycardia in patients with implantable cardioverter-defibrillators (ICDs) offers a challenge with no set guidelines regarding which therapy offers a best safety and efficacy profile.

STUDY QUESTION

Which therapeutic strategy, among antiarrhythmic drugs and catheter ablation (CA), offers the most effective and safe approach in patients with ICDs?

DATA SOURCES

Randomized controlled trials (RCTs) comparing the efficacy and safety of antiarrhythmic drugs or CA against a placebo group. RCTs were identified from a comprehensive search in PubMed, Embase, and Cochrane library.

STUDY DESIGN

Our outcomes of interest were reductions in appropriate ICD shocks, inappropriate ICD shocks, and overall mortality. We used the event rates in both groups, and then using a frequentist approach employing a graph theory methodology, we constructed a network meta-analysis model.

RESULTS

Fourteen RCTs with 3815 participants and 6 different interventions treatments were included in our network meta-analysis. The most effective treatment for the prevention of recurrent ventricular tachycardia after ICD is amiodarone followed by CA. Amiodarone is most effective in the reduction of appropriate and inappropriate ICD shocks with an odds ratio (OR) of 0.29 [95% confidence interval (CI), 0.11-0.74] and 0.15 (95% CI, 0.04-0.60), respectively. CA was effective in the reduction of appropriate ICD shocks (OR, 0.41; 95% CI, 0.20-0.87), whereas sotalol was effective in the reduction of inappropriate ICD shocks (OR, 0.46; 95% CI, 0.22-0.95). There was no significant reduction in the overall mortality from any therapy. There was a trend of increased mortality associated with amiodarone therapy (OR, 2.40; 95% CI, 0.92-6.26).

CONCLUSIONS

Amiodarone remains the most efficacious therapy for the reduction of appropriate and inappropriate shocks in patients with ICD. No therapy resulted in mortality reduction, but amiodarone showed a trend toward increased mortality.

Evaluating class III antiarrhythmic agents as novel MYC targeting drugs in ovarian cancer

OBJECTIVE

To evaluate the utility of amiodarone and its derivative dronedarone as novel drug repositioning candidates in EOC and to determine the potential pathways targeted by these drugs.

METHODS

Drug-predict bioinformatics platform was used to assess the utility of amiodarone as a novel drug-repurposing candidate in EOC. EOC cells were treated with amiodarone and dronedarone. Cell death was assessed by Annexin V staining. Cell viability and cell survival were assessed by MTT and clonogenics assays respectively. c-MYC and mTOR/Akt axis were evaluated as potential targets. Effect on autophagy was determined by autophagy flux flow cytometry.

RESULTS

"DrugPredict" bioinformatics platform ranked Class III antiarrhythmic drug amiodarone within the top 3.9% of potential EOC drug repositioning candidates which was comparable to carboplatin ranking in the top 3.7%. Amiodarone and dronedarone were the only Class III antiarrhythmic drugs that decreased the cellular survival of both cisplatin-sensitive and cisplatin-resistant primary EOC cells. Interestingly, both drugs induced degradation of c-MYC protein and decreased the expression of known transcriptional targets of c-MYC. Furthermore, stable overexpression of non-degradable c-MYC partially rescued the effects of amiodarone and dronedarone induced cell death. Dronedarone induced higher autophagy flux in EOC cells as compared to amiodarone with decreased phospho-AKT and phospho-4EBP1 protein expression, suggesting autophagy induction due to inhibition of AKT/mTOR axis with these drugs. Lastly, both drugs also inhibited the survival of EOC tumor-initiating cells (TICs).

CONCLUSIONS

We provide the first evidence of class III antiarrhythmic agents as novel c-MYC targeting drugs and autophagy inducers in EOC. Since c-MYC is amplified in >40% ovarian tumors, our results provide the basis for repositioning amiodarone and dronedarone as novel c-MYC targeting drugs in EOC with potential extension to other cancers.

The risk of cardiac events in patients who received concomitant levofloxacin and amiodarone

OBJECTIVES

Levofloxacin and amiodarone are both known to prolong the QT interval. This study was conducted to estimate the risk of cardiac events in patients receiving concomitant levofloxacin and amiodarone.

METHODS

The study included patients who were admitted to a large academic community medical center from 1/2012 to 12/2015 and received both levofloxacin and amiodarone at some point during their hospitalization. Patients received concomitant or non-concomitant levofloxacin and amiodarone during hospitalization. The primary outcome was the occurrence of cardiac events during therapy. The secondary outcome was the proportion of patients with an electrocardiogram performed before and after initiation of therapy. Odds ratios for cardiac events were calculated using a multivariable logistic regression model with and without adjusting for the study variables. The concomitant group was further evaluated for predictors of the primary outcome using multivariable logistic regression.

RESULTS

This study included 240 patients, 164 (68.3%) of whom received concomitant levofloxacin and amiodarone. Concomitant medication therapy was associated with a greater than six-fold increased risk of cardiac events after adjusting for the study variables (Odds Ratio=6.20; 95% Confidence Interval=1.34-28.62).

CONCLUSIONS

Patients receiving concomitant amiodarone and levofloxacin experienced a five-fold increase in cardiac events compared to patients given either medication alone.

Adverse effects of amiodarone therapy in adults with congenital heart disease

OBJECTIVE

Amiodarone is a highly effective antiarrhythmic therapy, however its toxicity profile often limits treatment. This is particularly relevant in adults with congenital heart disease (CHD), who are often young and in whom other antiarrhythmic agents commonly fail or are contraindicated. We sought to determine incidence and predictors of adverse effects caused by amiodarone in adult CHD (ACHD).

DESIGN

A retrospective review of patients with moderate to complex ACHD treated with amiodarone at our center between 2000 and 2017 was performed. Incidence and predictors of adverse effects were described. Efficacy of amiodarone therapy in controlling the clinical arrhythmia was assessed as complete, partial, or failed.

RESULTS

Amiodarone was prescribed in 57 patients of 902 ACHD patients reviewed (6%), for a mean duration of 2.7 ± 4.3 years. Significant adverse effects occurred in 56%, most commonly thyroid dysfunction, with amiodarone-induced thyrotoxicosis (AIT) in 30% and amiodarone-induced hypothyroidism in 14%. AIT frequently led to arrhythmia exacerbation and occurred most in those with Fontan anatomy. Severe dermatological effects were seen in 7% and bradycardia requiring pacing in 5%. Interstitial lung disease, peripheral neuropathy and alopecia were observed in single cases. Amiodarone toxicity led to discontinuation of the drug in 42%. Amiodarone was highly effective when tolerated, however, achieving complete arrhythmia control in 63%, partial control in 35%, with failure to control in only one patient.

CONCLUSIONS

Amiodarone therapy is effective in moderate to complex ACHD patients, but is frequently limited by adverse effects. ACHD patients seem especially vulnerable to thyroid dysfunction, with Fontan patients in particular at increased risk of AIT.

Efficacy and adverse effects of sotalol in adults with congenital heart disease

INTRODUCTION

Adults with congenital heart disease (CHD) are predisposed to arrhythmias, which can often be refractory to medical therapy. Sotalol is an attractive alternative antiarrhythmic to amiodarone in this younger patient population, given the latter's toxicity profile, but it may have proarrhythmic effects. We therefore aimed to assess the efficacy and safety of sotalol in adults with CHD.

METHODS

We retrospectively assessed our adult CHD database for all patients ≥16 years old, with moderate to highly complex defects, who were prescribed sotalol between 2000 and 2017. Efficacy in treating the clinical arrhythmia was assessed as complete, partial or failure. Adverse effects, including proarrhythmia, were documented.

RESULTS

Sotalol was prescribed in 82 of 902 adult CHD patients reviewed (9%). The mean age at sotalol commencement was 31.8 ± 13.1 years, with a median time on sotalol of 2.8 years. The average prescribed dose was 122 ± 51 mg/daily. Sotalol was completely effective in 48% (n = 39), partially effective in 46% (n = 38) and failed to control the clinical arrhythmia in 6% (n = 5). Fifteen patients (18%) discontinued sotalol due to a side effect, most commonly fatigue or dyspnoea. No episodes of torsades de pointes or sudden cardiac death were observed. Significant bradycardia related to sotalol occurred in 13% (n = 11, with permanent pacing implemented in 4), and was associated with Fontan anatomy.

CONCLUSIONS

In moderate to highly complex adult CHD, sotalol was reasonably effective and safe in low doses. Side effects limiting treatment were typically non-life-threatening, with significant bradycardia related to sotalol more likely in Fontan patients.

Heparin Oligosaccharides Have Antiarrhythmic Effect by Accelerating the Sodium-Calcium Exchanger

Background: Blockage of the Na⁺/Ca²⁺ exchanger (NCX) is used to determine the role of NCX in arrhythmogenesis. Trisulfated heparin disaccharide (TD) and Low Molecular Weight Heparins (LMWHs) can directly interact with the NCX and accelerate its activity.

Objective: In this work, we investigated the antiarrhythmic effect of heparin oligosaccharides related to the NCX activity.

Methods: The effects of heparin oligosaccharides were tested on the NCX current (patch clamping) and intracellular calcium transient in rat cardiomyocytes. The effects of heparin oligosaccharides were further investigated in arrhythmia induced in isolated rat atria and rats in vivo.

Results: The intracellular Ca²⁺ concentration decreases upon treatment with either enoxaparin or ardeparin. These drugs abolished arrhythmia induction in isolated atria. The NCX antagonist KB-R7943 abolished the enoxaparin or ardeparin antiarrhythmic effects in isolated atria. In the in vivo measurements, injection of TD 15 min both before coronary occlusion or immediately after reperfusion, significantly prevented the occurrence of reperfusion-induced arrhythmias (ventricular arrhythmia and total AV block) and reduced the lethality rate. The patch clamping experiments showed that, mechanistically, TD increases the forward mode NCX current.

Conclusion: Together, the data shows that heparin oligosaccharides may constitute a new class of antiarrhythmic drug that acts by accelerating the forward mode NCX under calcium overload.

Efficacy and Safety of Low-Dose Amiodarone Therapy for Tachyarrhythmia in Congenital Heart Disease

Amiodarone (AMD) is a class III anti-arrhythmic drug that is highly effective for tachyarrhythmia treatment. AMD is widely used in adults with congenital heart disease (CHD); however, higher doses of AMD (> 200 mg/day) can cause various non-cardiac side effects. The purpose of this study was to assess the efficacy, safety, and adverse events of low-dose AMD (≤ 200 mg/day) for tachyarrhythmia in patients with CHD. We retrospectively studied 80 patients with CHD and tachyarrhythmia who received oral low-dose AMD (≤ 200 mg/day) from January 2004 to March 2016. Low-dose AMD therapy was used to treat supraventricular tachycardia (SVT) in 51 patients and ventricular tachycardia (VT) in 29 patients. After a mean follow-up of 2.9 years for SVT and 3.2 years for VT, 36% and 65% of the patients with SVT and VT, respectively, were free from a first tachyarrhythmia recurrence for 3 years. The incidence of AMD-induced side effects was 23%, and all these cases consisted of thyroid dysfunction. Low-dose AMD was effective for the treatment of tachyarrhythmia in patients with CHD and had a relatively low incidence of side effects. These findings suggest that low-dose AMD is useful and effective for decreasing the frequency of tachyarrhythmia in patients with CHD and has a low incidence of side effects.

Analysis of computed tomography density of liver before and after amiodarone administration

PURPOSE

To evaluate CT density of liver changes between before and after amiodarone administration.

MATERIALS AND METHODS

Twenty-five patients underwent non-enhanced CT including the liver before and after amiodarone administration. We set regions of interest (ROIs) at liver S8, spleen, paraspinal muscle, and calculated average CT density in these ROIs, then compared CT density between liver and other organs. Statistical differences between CT density of liver and various ratios before and after administration were determined, along with correlations between cumulative dose of amiodarone and liver density after administration, density change of liver, and various ratios after administration.

RESULTS

Liver density, liver-to-spleen ratio, and liver-to-paraspinal muscle ratio differed significantly between before and after amiodarone administration. No significant correlations were found between cumulative doses of amiodarone and any of liver density after administration, density change of liver, or various ratios after administration.

CONCLUSION

CT density of liver after amiodarone administration was significantly higher than that before administration. No correlations were identified between cumulative dose of amiodarone and either liver density after administration or density change of liver. Amiodarone usage should be checked when radiologists identify high density of the liver on CT.

Impact of Drug Induced Long QT Syndrome: A Systematic Review

Background

Drug induced long QT syndrome is quite common in daily clinical practice but its impact is unknown.

Methods

PubMed and EMBASE databases (until May 2, 2017) were searched to identify studies reporting drug induced long QT syndrome and followed the PRISMA guidelines. The main outcomes measured in these studies were QTc prolongation, ventricular arrhythmias, torsade de pointes (TdP) and death.

Results

Out of 176 non-duplicate reports, 36 studies satisfied inclusion criteria and provided data on patients exposed to drugs that can potentially cause long QT. Totally, 14,756 patients were exposed and 930 patients (6.3%) were found to have QTc prolongation. The number of males was 6,400 and females were 5,723 patients. The mean age of the patients was 43.8 ± 9.36 years. Ventricular arrhythmias were found in 379 patients (2.6%), 26 patients were found to have premature atrial contractions (PACs) and premature ventricular contractions (PVCs). TdP was found in 49 patients (0.33 %), sudden cardiac death (SCD) was found in five patients and 586 patients were found to have all-cause mortality.

Conclusions

Around 6% of patients have risk of QT prolongation when exposed but only 0.3% developed TdP and 2.6% developed ventricular arrhythmias. Risk of developing arrhythmias is higher with concomitant use of multiple QT prolonging drugs.

Amiodarone: A Newly Discovered Association with Bilateral Vestibulopathy

Background

Bilateral vestibulopathy (BVP) is a debilitating disorder characterized by the hypofunction of both vestibular end organs or nerves. The most frequent identifiable causes of BVP are ototoxic drug effects, infectious and autoimmune disorders. However, the majority of cases remain idiopathic. Very recently, the first discovery of a clinical case of Amiodarone-associated BVP has been reported.

Methods

An overview of the literature concerning the relation between amiodarone toxicity and BVP is presented and discussed.

Results

Older reports on amiodarone-induced symptoms of vertigo and gait instability lack a description of vestibular function test results. Recent evidence from retrospective studies including vestibular function testing in patients taking amiodarone have identified the drug as the hitherto unsuspected potential cause of a relatively large proportion of cases with “idiopathic” BVP.

Conclusion

Patients who receive amiodarone should be monitored with vestibular function testing in order to recognize potential adverse effects on the vestibular system and allow for an informed decision on possible drug reduction or withdrawal.

Have the Findings from Clinical Risk Prediction and Trials Any Key Messages for Safety Pharmacology?

Anti-arrhythmic drugs are a mainstay in the management of symptoms related to arrhythmias, and are adjuncts in prevention and treatment of life-threatening ventricular arrhythmias. However, they also have the potential for pro-arrhythmia and thus the prediction of arrhythmia predisposition and drug response are critical issues. Clinical trials are the latter stages in the safety testing and efficacy process prior to market release, and as such serve as a critical safeguard. In this review, we look at some of the lessons to be learned from approaches to arrhythmia prediction in patients, clinical trials of drugs used in the treatment of arrhythmias, and the implications for the design of pre-clinical safety pharmacology testing.

Ventricular Tachycardia with ICD Shocks: When to Medicate and When to Ablate

PURPOSE OF REVIEW

Ventricular tachycardia occurrence in implantable cardioverter defibrillator (ICD) patients may result in shock delivery and is associated with increased morbidity and mortality. In addition, shocks may have deleterious mechanical and psychological effects. Prevention of ventricular tachycardia (VT) recurrence with the use of antiarrhythmic drugs or catheter ablation may be warranted. Antiarrhythmic drugs are limited by incomplete efficacy and an unfavorable adverse effect profile. Catheter ablation can be effective but acute complications and long-term VT recurrence risk necessitating repeat ablation should be recognized. A shared clinical decision process accounting for patients' cardiac status, comorbidities, and goals of care is often required.

RECENT FINDINGS

There are four published randomized trials of catheter ablation for sustained monomorphic VT (SMVT) in the setting of ischemic heart disease; there are no randomized studies for non-ischemic ventricular substrates. The most recent trial is the VANISH trial which randomly allocated patients with ICD, prior infarction, and SMVT despite first-line antiarrhythmic drug therapy to catheter ablation or more aggressive antiarrhythmic drug therapy. During 28 months of follow-up, catheter ablation resulted in a 28% relative risk reduction in the composite endpoint of death, VT storm, and appropriate ICD shock (p = 0.04). In a subgroup analysis, patients having VT despite amiodarone had better outcomes with ablation as compared to increasing amiodarone dose or adding mexiletine. There is evidence for the effectiveness of both catheter ablation and antiarrhythmic drug therapy for patients with myocardial infarction, an implantable defibrillator, and VT. If sotalol is ineffective in suppressing VT, either catheter ablation or initiation of amiodarone is a reasonable option. If VT occurs despite amiodarone therapy, there is evidence that catheter ablation is superior to administration of more aggressive antiarrhythmic drug therapy. Early catheter ablation may be appropriate in some clinical situations such as patients presenting with relatively slow VT below ICD detection, electrical storms, hemodynamically stable VT, or in very selected patients with left ventricular assist devices. The optimal first-line suppressive therapy for VT, after ICD implantation and appropriate programming, remains to be determined. Thus far, there has not been a randomized controlled trial to compare catheter ablation to antiarrhythmic drug therapy as a first-line treatment; the VANISH-2 study has been initiated as a pilot to examine this question.

Comparison of the effects of IK,ACh, IKr, and INa block in conscious dogs with atrial fibrillation and on action potentials in remodeled atrial trabeculae

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major cause of morbidity and mortality. Traditional antiarrhythmic agents used for restoration of sinus rhythm have limited efficacy in long-term AF and they may possess ventricular proarrhythmic adverse effects, especially in patients with structural heart disease. The acetylcholine receptor-activated potassium channel (I_K,ACh) represents an atrial selective target for future AF management. We investigated the effects of the I_K,ACh blocker tertiapin-Q (TQ), a derivative of the honeybee toxin tertiapin, on chronic atrial tachypacing-induced AF in conscious dogs, without the influence of anesthetics that modulate a number of cardiac ion channels. Action potentials (APs) were recorded from right atrial trabeculae isolated from dogs with AF. TQ significantly and dose-dependently reduced AF incidence and AF episode duration, prolonged atrial effective refractory period, and prolonged AP duration. The reference drugs propafenone and dofetilide, both used in the clinical management of AF, exerted similar effects against AF in vivo. Dofetilide prolonged atrial AP duration, whereas propafenone increased atrial conduction time. TQ and propafenone did not affect the QT interval, whereas dofetilide prolonged the QT interval. Our results show that inhibition of I_K,ACh may represent a novel, atrial-specific target for the management of AF in chronic AF.

Rapid onset of amiodarone induced pulmonary toxicity after lung lobe resection - A case report and review of recent literature

Amiodarone-induced pulmonary toxicity (APT) is a severe side effect that can lead to lung fibrosis or fatal respiratory failure. Usually APT occurs during long term therapy after administration of prolonged loading doses or high cumulative doses. We present the case of a 58 year old woman who underwent thoracic surgery with lobe resection. She developed atrial fibrillation with hemodynamic-instability on the first post-operative day. We initiated amiodarone therapy and four days later she developed respiratory failure. The pulmonary function further deteriorated showing signs of an acute respiratory distress syndrome (ARDS). We therefore started mechanical ventilation, but still the gas exchange did not improve. A computer tomography-(CT)-scan presented bilateral interstitial and alveolar infiltrations. The patient also presented with leukocytosis, elevated C-reactive protein (CRP) levels however without elevated procalcitonin (PCT) concentrations. In the tracheal secretion we only harvested foam cells, but got no evidence for pathogens causing pneumonia. We immediately started glucocorticoid therapy with prednisolone 50 mg/d for five days. Almost instantaneously the gas exchange ameliorated. We were able to wean the patient from the respirator within five days. Pulmonary infiltrations were nearly vanished in a CT-scan few days later and completely disappeared in follow up examinations. This case demonstrates a per-acute onset of APT caused by a low loading dose in association with thoracic surgery. The initiation of glucocorticoid therapy in parallel to amiodarone withdrawal led to full recovery of the patient. One should consider APT when signs of pulmonary failure occur during brief periods of amiodarone therapy especially after thoracic surgery.

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Amiodarone-induced pulmonary toxicity (APT) can develop after low dose and short term amiodarone therapy.

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The early generation of APT is supported by thoracic surgery.

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APT can cause severe adult respiratory distress syndrome, leading to respiratory failure.

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Glucocorticoid therapy ameliorates APT symptoms and can restore respiratory failure in early state.

Amiodarone-Induced Third Degree Atrioventricular Block and Extreme QT Prolongation Generating Torsade Des Pointes in Paroxysmal Atrial Fibrillation

Amiodarone is still the most potent antiarrhythmic drug in the prevention of life threatening ventricular arrhythmias and demonstrates a very low incidence of torsade de pointes. An unusual case of an 81-year-old woman who developed serious abnormalities of the conduction system of the heart and torsade des pointes during intravenous infusion of amiodarone for the treatment of paroxysmal atrial fibrillation is described. To the best of our knowledge, this is the first case showing an association of intravenous amiodarone-induced third degree atrioventricular block and extreme QT interval prolongation generating torsade des pointes in a patient with paroxysmal atrial fibrillation who required an implantable cardioverter-defibrillator. Currently, amiodarone is still one of the few remaining treatment options for the medical therapeutic management of serious ventricular arrhythmias and to reduce the incidence of atrial fibrillation without increasing mortality or sudden cardiac death rates in heart failure patients like our elderly present patient. Nevertheless, we have to keep in mind that intravenous amiodarone may generate serious abnormalities of the conduction system of the heart and lethal ventricular arrhythmias in certain patients.

Topical amiodarone during cardiac surgery: Does epicardial application of amiodarone prevent postoperative atrial fibrillation?

OBJECTIVES

Atrial fibrillation (AF) is a common complication after cardiac surgery. Topical amiodarone on the epicardium may help prevent postoperative AF while avoiding the side effects of its systemic administration. The purpose of this study was to evaluate the all-comer strategy of epicardial amiodarone application for the prevention of postoperative AF.

METHODS

A retrospective observational study was performed that evaluated the incidence of new-onset AF in a consecutive series of cardiac surgery patients who were treated with either no amiodarone (historical control, n = 100), epicardial application of amiodarone mixed in a topical hydrogel (n = 50), or epicardial application of an amiodarone-soaked sealant patch (n = 50). Perioperative data were compared between the 3 groups, with all patients receiving continuous postoperative telemetry to monitor for new-onset AF.

RESULTS

The cohort consisted of 200 cardiac surgery patients (coronary bypass 82%, valve surgery 24%) who had no history of AF (mean age 71.0 years, 28% female). Among the 3 groups, the incidence of postoperative AF did not significantly differ, with 29 of 100 (29%) patients in the historical control group having new AF, compared with 18 of 50 (36%) in the amiodarone-hydrogel group, and 18 of 50 (36%) in the amiodarone-patch group (P = .56). The results did not differ when the analysis was restricted to coronary bypass patients only (n = 142, 27% vs 38% vs 32%, no-amiodarone vs amiodarone-hydrogel vs amiodarone-patch, respectively, P = .56). In multivariate logistic regression analysis, only older age (P = .001) was significantly associated with new-onset AF, but the use of topical amiodarone was not.

CONCLUSIONS

Routine epicardial application of topical amiodarone was not associated with a reduction in the incidence of new-onset postoperative AF in this observational study of older patients, leading us to question its role in contemporary cardiac surgical practice.

Class III antiarrhythmic drugs amiodarone and dronedarone impair KIR 2.1 backward trafficking

Drug‐induced ion channel trafficking disturbance can cause cardiac arrhythmias. The subcellular level at which drugs interfere in trafficking pathways is largely unknown. K_IR2.1 inward rectifier channels, largely responsible for the cardiac inward rectifier current (I_K1), are degraded in lysosomes. Amiodarone and dronedarone are class III antiarrhythmics. Chronic use of amiodarone, and to a lesser extent dronedarone, causes serious adverse effects to several organs and tissue types, including the heart. Both drugs have been described to interfere in the late‐endosome/lysosome system. Here we defined the potential interference in K_IR2.1 backward trafficking by amiodarone and dronedarone. Both drugs inhibited I_K1 in isolated rabbit ventricular cardiomyocytes at supraclinical doses only. In HK‐KWGF cells, both drugs dose‐ and time‐dependently increased K_IR2.1 expression (2.0 ± 0.2‐fold with amiodarone: 10 μM, 24 hrs; 2.3 ± 0.3‐fold with dronedarone: 5 μM, 24 hrs) and late‐endosomal/lysosomal K_IR2.1 accumulation. Increased K_IR2.1 expression level was also observed in the presence of Na_v1.5 co‐expression. Augmented K_IR2.1 protein levels and intracellular accumulation were also observed in COS‐7, END‐2, MES‐1 and EPI‐7 cells. Both drugs had no effect on K_v11.1 ion channel protein expression levels. Finally, amiodarone (73.3 ± 10.3% P < 0.05 at −120 mV, 5 μM) enhanced I_KIR2.1 upon 24‐hrs treatment, whereas dronedarone tended to increase I_KIR2.1 and it did not reach significance (43.8 ± 5.5%, P = 0.26 at −120 mV; 2 μM). We conclude that chronic amiodarone, and potentially also dronedarone, treatment can result in enhanced I_K1 by inhibiting K_IR2.1 degradation.

Amiodarone-induced loculated pleural effusion without pulmonary parenchymal involvement: A case report and literature review

Amiodarone is an extremely effective antiarrhythmic drug that is known to cause many adverse effects such as pulmonary, thyroid, and liver toxicities. Of these, pulmonary toxicity is most serious. Pulmonary toxicity can present as interstitial pneumonitis, organizing pneumonia, pulmonary nodules and masses, and very rarely pleural effusions. We present a case of a 73-year-old male who presented with progressive exertional dyspnea, nonproductive cough, generalized fatigue, and weakness. He was found to have multiorgan toxicity secondary to long-term treatment with high doses of amiodarone. This case illustrates that amiodarone may cause toxicity involving multiple organs simultaneously in patients receiving long-term therapy and represents the first reported case of amiodarone-induced loculated pleural effusion without associated lung parenchymal involvement.

Association between N-desethylamiodarone/amiodarone ratio and amiodarone-induced thyroid dysfunction

PURPOSE

We used a retrospective data mining approach to explore the association between serum amiodarone (AMD) and N-desethylamiodarone (DEA) concentrations and thyroid-related hormone levels.

METHODS

Laboratory data sets from January 2012 to April 2016 were extracted from the computerized hospital information system database at the National Cerebral and Cardiovascular Center (NCVC). Data sets that contained serum AMD and DEA concentrations and thyroid function tests, including thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3), were analyzed.

RESULTS

A total of 1831 clinical laboratory data sets from 330 patients were analyzed. Data sets were classified into five groups (euthyroidism, hyperthyroidism, subclinical hyperthyroidism, hypothyroidism, and subclinical hypothyroidism) based on the definition of thyroid function in our hospital. Most abnormal levels of thyroid hormones were observed within the therapeutic range of serum AMD and DEA concentrations. The mean DEA/AMD ratio in the hyperthyroidism group was significantly higher than that in the euthyroidism group (0.95 ± 0.42 vs. 0.87 ± 0.28, p = 0.0209), and the mean DEA/AMD ratio in the hypothyroidism group was significantly lower than that in the euthyroidism group (0.77 ± 0.26 vs. 0.87 ± 0.28, p = 0.0038). The suppressed TSH group (0.98 ± 0.41 vs. 0.87 ± 0.28, p < 0.001) and the elevated FT4 level group (0.90 ± 0.33 vs. 0.84 ± 0.27, p = 0.0037) showed significantly higher DEA/AMD ratios compared with normal level groups. The elevated TSH group showed a significantly lower DEA/AMD ratio compared with the normal group (0.81 ± 0.25 vs. 0.87 ± 0.28, p < 0.0001).

CONCLUSIONS

High and low DEA/AMD ratios were associated with AMD-induced hyperthyroidism and hypothyroidism, respectively. The DEA/AMD ratio may be a predictive marker for AMD-induced thyroid dysfunction.

Adverse Drug Reactions in the Intensive Care Unit

Adverse drug reactions (ADRs) are undesirable effects of medications used in normal doses [1]. ADRs can occur during treatment in an intensive care unit (ICU) or result in ICU admissions. A meta-analysis of 4139 studies suggests the incidence of ADRs among hospitalized patients is 17% [2]. Because of underreporting and misdiagnosis, the incidence of ADRs may be much higher and has been reported to be as high as 36% [3]. Critically ill patients are at especially high risk because of medical complexity, numerous high-alert medications, complex and often challenging drug dosing and medication regimens, and opportunity for error related to the distractions of the ICU environment [4]. Table 1 summarizes the ADRs included in this chapter.

Will There Be a Cure for Ebola?

Despite the unprecedented Ebola virus outbreak response in West Africa, no Ebola medical countermeasures have been approved by the US Food and Drug Administration. However, multiple valuable lessons have been learned about the conduct of clinical research in a resource-poor, high risk-pathogen setting. Numerous therapeutics were explored or developed during the outbreak, including repurposed drugs, nucleoside and nucleotide analogues (BCX4430, brincidofovir, favipiravir, and GS-5734), nucleic acid-based drugs (TKM-Ebola and AVI-7537), and immunotherapeutics (convalescent plasma and ZMapp). We review Ebola therapeutics progress in the aftermath of the West Africa Ebola virus outbreak and attempt to offer a glimpse of a path forward.

Corneal Densitometry as a Novel Technique for Monitoring Amiodarone Therapy

PURPOSE

The clinical efficacy and toxicity of amiodarone may be determined more effectively by tissue deposition than by levels of the agent in serum. Therefore, corneal densitometry might be useful for therapeutic monitoring. The aim of the study is to evaluate Scheimpflug corneal densitometry in patients with amiodarone keratopathy (AK).

DESIGN

Comparative case series.

PARTICIPANTS

Sixty-six patients receiving amiodarone therapy and 66 healthy controls were consecutively enrolled in this study.

METHODS

Patients were examined using the Oculus Pentacam (Wetzlar, Germany).

MAIN OUTCOME MEASURES

Densitometry data from different corneal layers and different annuli were extracted, analyzed, and compared with densitometry values of healthy controls. Duration of treatment, cumulative dose, Orlando stage (slit-lamp biomicroscopy), and serum concentrations of amiodarone and N-desethylamiodarone also were determined, and the correlation to different densitometry data was evaluated.

RESULTS

The total corneal light backscatter at total corneal thickness and at total diameter was significantly higher in the amiodarone group compared with the control group (AK group: 28.3±5.2; control group: 24.4±4.2; P < 0.001). Upon dividing the corneal surface into different layers at total thickness, the differences were significant in all layers (P < 0.001). The serum concentrations of the metabolite N-desethylamiodarone correlate with densitometry values, especially in the 0- to 2-mm annulus in the anterior layer (r = 0.419; P = 0.001), whereas the cumulative dose and duration of treatment correlate significantly with the densitometry values in the 0- to 2-mm annulus at total thickness (P = 0.014 and P = 0.022, respectively).

CONCLUSIONS

Corneal densitometry is a useful, objective method for quantifying AK and can help in monitoring amiodarone therapy. The serum concentration of the active metabolite N-desethylamiodarone correlates with the extent of keratopathy in the anterior layer, whereas chronic changes in the stroma correlate with the cumulative dose and duration of treatment.

Anti-arrhythmic medications increase non-cardiac mortality - A meta-analysis of randomized control trials

Introduction

Anti-arrhythmic medications (AAMs) are known to increase cardiac mortality significantly due to their pro-arrhythmic effects. However, the effect of AAMs on non-cardiac mortality has not been evaluated.

Methods

Trials published in English language journals from 1990 to 2015 were thoroughly retrieved by searching websites such as PubMed, Medline, Cochrane Library, and Google Scholar. Randomized controlled trials reporting non-cardiac deaths as primary or secondary outcomes were used to compare AAMs to non-arrhythmic therapy (AV nodal blocking agents, implantable cardiovascular defibrillation (ICD), or placebo). Information regarding the sample size, treatment type, baseline characteristics, and outcomes was obtained by using a standardized protocol. The fixed effect model was used to perform meta-analysis, and results were expressed in terms of odds ratio (OR) with confidence interval (CI) of 95%, inter study heterogeneity was assessed using I². Intention to treat principle was applied to extract data.

Results

Total of 18,728 patients were enrolled in 15 trials; 9359 patients received AAMs and 9369 received non-arrhythmic therapy. AAMs were associated with an increased risk of non-cardiac mortality (OR=1.30, [95% CI: 1.12, 1.50], p=0.0005, I² index=24%) and all-cause mortality (OR=1.09, [95% CI: 1.01, 1.18], p=0.04, I²=54%) as compared to non-arrhythmic therapy. There was no difference in the cardiac mortality (OR=1.01, [95% CI: 0.92, 1.11], p=0.82, I²=53%) or arrhythmic mortality (OR=1.00, [95% CI: 0.89, 1.13], p=0.94, I²=64%) between the two groups.

Conclusion

AAMs are associated with an increased risk of non-cardiac and all-cause mortality. The effect of AAMs, especially amiodarone, on non-cardiac mortality requires further evaluation.

Risk factors for amiodarone-induced thyroid dysfunction in Japan

Background

Amiodarone is associated with a number of significant adverse effects, including elevated transaminase levels, pulmonary fibrosis, arrhythmia, and thyroid dysfunction. Although thyroid dysfunction is considered to be a common and potentially serious adverse effect of amiodarone therapy, the exact pathogenesis remains unknown because of its complex manifestations. Therefore, the prevalence of, and risk factors for, amiodarone-induced thyroid dysfunction in Japanese patients were investigated in the present study.

Methods

A retrospective analysis of patients treated with amiodarone between January 2012 and December 2013 was performed. A total of 317 patients with euthyroidism, or subclinical hyperthyroidism or hypothyroidism, were enrolled in this study.

Results

After being treated with amiodarone, 30 (9.5%) and 60 patients (18.9%) developed amiodarone-induced hyperthyroidism and amiodarone-induced hypothyroidism, respectively. Ten (33.3%) patients with amiodarone-induced hyperthyroidism and 40 (66.6%) with amiodarone-induced hypothyroidism were diagnosed within two years of the initiation of amiodarone therapy. Dilated cardiomyopathy (DCM) [Adjusted odds ratio (OR) 3.30 (95% confidence interval (CI): 1.26–8.90)], and cardiac sarcoidosis [Adjusted OR 6.47 (95% CI: 1.60–25.77)] were identified as predictors of amiodarone-induced hyperthyroidism. The baseline free thyroxine (T4) level [Adjusted OR 0.13 (95% CI: 0.03–0.68)], and thyroid-stimulating hormone (TSH) level [Adjusted OR1.47 (95% CI: 1.26–1.74)] were identified as predictors of amiodarone-induced hypothyroidism.

Conclusion

DCM and cardiac sarcoidosis were identified as risk factors for amiodarone-induced hyperthyroidism. Risk factors for amiodarone-induced hypothyroidism included higher baseline TSH level and lower baseline free T4 level, suggesting that subclinical hypothyroidism may be a potential risk factor for the development of amiodarone-induced hypothyroidism.

Practical Management Guide for Clinicians Who Treat Patients with Amiodarone

Amiodarone, an iodinated benzofuran derivative with Class I, II, III, and IV antiarrhythmic properties, is the most commonly used antiarrhythmic drug used to treat supraventricular and ventricular arrhythmias. Appropriate use of this drug, with its severe and potentially life-threatening adverse effects, requires an essential understanding of its risk-benefit properties in order to ensure safety. The objective of this review is to afford clinicians who treat patients receiving amiodarone an appropriate management strategy for its safe use. The authors of this consensus management guide have thoroughly reviewed and evaluated the existing literature on amiodarone and apply this information, along with the collective experience of the authors, in its development. Provided are management guides on the intravenous and oral dosing of amiodarone, appropriate outpatient follow-up of patients taking the drug, its recognized adverse effects, and recommendations on when to consult specialists to help in patient management. All clinicians must be cognizant of the appropriate use, follow-up, and adverse reactions of amiodarone. The responsibility incurred by those treating such patients cannot be overemphasized.

Environmental Iodine Content, Female Sex and Age Are Associated with New-Onset Amiodarone-Induced Hypothyroidism: A Systematic Review and Meta-Analysis of Adverse Reactions of Amiodarone on the Thyroid

OBJECTIVES

To investigate the incidence of new-onset amiodarone-induced hypothyroidism (AIH) and the associated risk factors.

METHODS

We performed a systematic search in MEDLINE, Embase, the Cochrane Library and the Chinese database from 1995 to 2015. Studies that investigated amiodarone-related adverse reactions on the thyroid were included. A random-effect model was used for the meta-analysis to investigate the incidence rate of AIH and associated risk factors.

RESULTS

We identified 465 studies, of which data from 9 studies were included, comprising 1,972 patients. The incidence of AIH was 14.0% (95% confidence interval, CI, 8.7-21.7%) as a whole; it was higher in areas with a high than a low iodine content in the environment (20.3 vs. 8.7%, p < 0.001); subgroup analysis showed that AIH occurred in 19.2% (95% CI 10.2-33.1%) of women and 13.3% (95% CI 7.9-21.7%) of men (p < 0.001). Meta-regression analysis indicated a positive correlation with the mean age and percentage of women.

CONCLUSIONS

The occurrence of AIH is a relatively frequent complication of amiodarone, and older women are more likely to develop AIH, especially in areas with a high iodine content in the environment, and restriction of total exposure to iodine might decrease the incidence of AIH.

Prescription sequence symmetry analysis: assessing risk, temporality, and consistency for adverse drug reactions across datasets in five countries

Background

Prescription sequence symmetry analysis (PSSA) is a signal detection method for adverse drug events. Its capacity to consistently detect adverse drug events across different settings has not been tested. We aimed to determine the consistency of PSSA results for detecting positive and negative control adverse drug events across different settings.

Methods

Using a distributed network model, we analyzed prescription dispensing data using PSSA in Australia, Hong Kong, Japan, Korea, and Taiwan. Positive control was amiodarone and thyroxine, as a marker of amiodarone-induced hypothyroidism, a known adverse event with a clear temporal relationship to amiodarone initiation. Negative controls were amiodarone and allopurinol, as a marker of amiodarone-induced gout and thyroxine and allopurinol, as a marker of thyroxine-induced gout. Gout is not recorded as an adverse event in product information for either medicine. Adjusted sequence ratios (ASR) were calculated for each country. Pooled estimates were obtained by using the generic inverse variance method.

Results

A positive association was identified between amiodarone and thyroxine in all settings with a pooled ASR 2.63 (95% confidence interval (CI) 1.47–4.72). Temporal analysis showed the effect occurred within the first few weeks of treatment. No significant associations were found for the negative controls in any setting; pooled ASR were 0.76 (95%CI 0.62–0.93) and 0.98 (95%CI 0.85–1.12) for amiodarone-allopurinol and thyroxine-allopurinol, respectively.

Conclusion

Despite different health settings, different populations, and different patterns of medicine utilization, PSSA gave consistent estimates across countries for a well-known positive association and two negative control adverse events. © 2015 The Authors Pharmacoepidemiology and Drug Safety Published by John Wiley & Sons Ltd.

A detailed description and assessment of outcomes of patients with hospital recorded QTc prolongation

Corrected QT (QTc) interval prolongation has been shown to be an independent predictor of mortality in many clinical settings and is a common finding in hospitalized patients. The causes and outcomes of patients with extreme QTc interval prolongation during a hospital admission are poorly described. The aim of this study was to prospectively identify patients with automated readings of QTc intervals >550 ms at 1 academic tertiary hospital. One hundred seventy-two patients with dramatic QTc interval prolongation (574 ± 53 ms) were identified (mean age 67.6 ± 15.1 years, 48% women). Most patients had underlying heart disease (60%), predominantly ischemic cardiomyopathy (43%). At lease 1 credible and presumed reversible cause associated with QTc interval prolongation was identified in 98% of patients. The most common culprits were QTc interval-prolonging medications, which were deemed most responsible in 48% of patients, with 25% of these patients taking ≥2 offending drugs. Two patients were diagnosed with congenital long-QT syndrome. Patients with electrocardiograms available before and after hospital admission demonstrated significantly lower preadmission and postdischarge QTc intervals compared with the QTc intervals recorded in the hospital. In conclusion, in-hospital mortality was high in the study population (29%), with only 4% of patients experiencing arrhythmic deaths, all of which were attributed to secondary causes.

Ranolazine in the treatment of atrial fibrillation: Results of the dose-ranging RAFFAELLO (Ranolazine in Atrial Fibrillation Following An ELectricaL CardiOversion) study

BACKGROUND

Currently available antiarrhythmic agents for the treatment of atrial fibrillation (AF) have important limitations, leaving an unmet need for safe and effective therapy. Ranolazine is an approved antianginal agent with a favorable safety profile and electrophysiologic properties suggesting a potential role in the treatment of AF.

OBJECTIVE

The purpose of this study was to assess the safety and efficacy of ranolazine in the prevention of AF recurrence after successful electrical cardioversion and to ascertain the most appropriate dose of this agent.

METHODS

This prospective, multicenter, randomized, double-blind, placebo-control parallel group phase II dose-ranging trial randomized patients with persistent AF (7 days to 6 months) 2 hours after successful electrical cardioversion to placebo, or ranolazine 375 mg, 500 mg, or 750 mg bid. Patients were monitored daily by transtelephonic ECG. The primary end-point was the time to first AF recurrence.

RESULTS

Of 241 patients randomized, 238 took at least 1 drug dose. Ranolazine proved to be safe and tolerable. No dose of the drug significantly prolonged time to AF recurrence. AF recurred in 56.4%, 56.9%, 41.7%, and 39.7% of patients in the placebo, ranolazine 375 mg, ranolazine 500 mg, and ranolazine 750 mg groups, respectively. The reduction in overall AF recurrence in the combined 500-mg and 750-mg groups was of borderline significance compared to the placebo group (P = .053) and significant compared to 375-mg group (P = .035).

CONCLUSION

No dose of ranolazine significantly prolonged time to AF recurrence. However, the 500-mg and 750 mg-groups combined reduced AF recurrences, suggesting a possible role for this agent in the treatment of AF.