Sex differences in the relationship between amiodarone use and the need for permanent pacing in patients with atrial fibrillation

Small Organic Compounds Mimicking the Effector Domain of Myristoylated Alanine-Rich C-Kinase Substrate Stimulate Female-Specific Neurite Outgrowth

Myristoylated alanine-rich C-kinase substrate (MARCKS) is a critical member of a signaling cascade that influences disease-relevant neural functions such as neural growth and plasticity. The effector domain (ED) of MARCKS interacts with the extracellular glycan polysialic acid (PSA) through the cell membrane to stimulate neurite outgrowth in cell culture. We have shown that a synthetic ED peptide improves functional recovery after spinal cord injury in female but not male mice. However, peptides themselves are unstable in therapeutic applications, so we investigated more pharmacologically relevant small organic compounds that mimic the ED peptide to maximize therapeutic potential. Using competition ELISAs, we screened small organic compound libraries to identify molecules that structurally and functionally mimic the ED peptide of MARCKS. Since we had shown sex-specific effects of MARCKS on spinal cord injury recovery, we assayed neuronal viability as well as neurite outgrowth from cultured cerebellar granule cells of female and male mice separately. We found that epigallocatechin, amiodarone, sertraline, tegaserod, and nonyloxytryptamine bind to a monoclonal antibody against the ED peptide, and compounds stimulate neurite outgrowth in cultured cerebellar granule cells of female mice only. Therefore, a search for compounds that act in males appears warranted.

Sex Differences in Atrial Fibrillation

PURPOSE OF REVIEW

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. The estimated lifetime risk of developing AF is higher in men; however, due to differences in life expectancy, the overall prevalence is higher among women, particularly in the older age group. Sex differences play an important role in the pathophysiology, presentation, and clinical outcomes of AF. Awareness of these differences minimizes the potential for disparities in AF management. Our review summarizes the current literature on sex differences in AF, including the epidemiology, pathophysiology, risk factors, clinical symptomatology, mechanisms, treatment, and outcomes. We also explore the implications of these differences for clinical practice and future research.

RECENT FINDINGS

Women are more likely to present with atypical symptoms, have a higher stroke risk, and have a worse quality of life with AF when compared to men. Despite this, they are less likely to receive rhythm control strategies and anticoagulants. The sex-based differences in AF pathology and management might be a combination of inherent biological and hormonal differences, and implicit bias of the research entities and treating clinicians. Our review stresses the need for further sex-specific research in the pathophysiology of AF and opens a dialogue on personalized medicine, where management strategies can be tailored to individual patient characteristics, including sex.

A systematic review on sex differences in adverse drug reactions related to psychotropic, cardiovascular, and analgesic medications

Background and objective: Adverse drug reactions (ADRs) are the main safety concerns of clinically used medications. Accumulating evidence has shown that ADRs can affect men and women differently, which suggests sex as a biological predictor in the risk of ADRs. This review aims to summarize the current state of knowledge on sex differences in ADRs with the focus on the commonly used psychotropic, cardiovascular, and analgesic medications, and to aid clinical decision making and future mechanistic investigations on this topic. Methods: PubMed search was performed with combinations of the following terms: over 1,800 drugs of interests, sex difference (and its related terms), and side effects (and its related terms), which yielded over 400 unique articles. Articles related to psychotropic, cardiovascular, and analgesic medications were included in the subsequent full-text review. Characteristics and the main findings (male-biased, female-biased, or not sex biased ADRs) of each included article were collected, and the results were summarized by drug class and/or individual drug. Results: Twenty-six articles studying sex differences in ADRs of six psychotropic medications, ten cardiovascular medications, and one analgesic medication were included in this review. The main findings of these articles suggested that more than half of the ADRs being evaluated showed sex difference pattern in occurrence rate. For instance, lithium was found to cause more thyroid dysfunction in women, and amisulpride induced prolactin increase was more pronounced in women than in men. Some serious ADRs were also found to exert sex difference pattern, such as clozapine induced neutropenia was more prevalent in women whereas simvastatin/atorvastatin-related abnormal liver functions were more pronounced in men.

Future bradyarrhythmia in patients with hypertrophic cardiomyopathy

Background

A few studies to evaluate an incidence of bradyarrhythmia in patients with hypertrophic cardiomyopathy (HCM) have been reported.

Methods

We enrolled 161 patients with HCM to evaluate their bradyarrhythmia risk, especially the risk of patients who were at risk for sudden cardiac death (SCD) and eligible for implantation of an implantable cardiac defibrillator (ICD). We defined symptomatic bradyarrhythmia requiring a pacing therapy as a bradyarrhythmia event and collected the data on an occurrence of the event after the time of diagnosis of HCM. The incidence of bradyarrhythmia events was compared between patients with ICD indications (ICD-candidate group) and those without (non-ICD-candidate group). Furthermore, we investigated the associated factors with bradyarrhythmia events using a Cox proportional-hazards model.

Results

During 5.5 ± 4.4 years follow-up, bradyarrhythmia events occurred in 8% (13 patients) of whole patients, and in 15% of the ICD-candidate group (n = 74). In contrast, only 2 events (2%) occurred in the non-ICD-candidate group. The incidence of bradyarrhythmia in the ICD-candidate group was significantly higher than that in the non-ICD-candidate group (log-rank p = 0.015). In the ICD-candidate group, a Cox proportional-hazards model demonstrated that lower heart rate at the time of diagnosis (HR: 1.072, 95%CI: 1.012 to 1.135, p = 0.018), and an eligibility of ICD implantation for secondary prevention of SCD (HR: 9.092, 95%CI: 2.644 to 31.258, p < 0.001) were significantly associated with future bradyarrhythmia.

Conclusions

HCM patients with eligibility for ICD implantation, especially for secondary prevention of SCD, more frequently suffered from bradyarrhythmia events.

Amiodarone: A Comprehensive Guide for Clinicians

Amiodarone is an effective antiarrhythmic medication frequently used in practice for both ventricular and atrial arrhythmias. Though classified as a class III antiarrhythmic, it affects all phases of the cardiac action potential. However, the drug has several side effects, including thyroid abnormalities, pulmonary fibrosis, and transaminitis, for which routine monitoring is recommended. It also interacts with several medications, such as warfarin, simvastatin, and atorvastatin, and many HIV antiretroviral medications. Given the common use of this medication in medical practice, it is vital that clinicians understand the indications, contraindications, dosing, side effects, and interactions of this medication. A thorough understanding of these topics is essential for clinicians to ensure safe and effective use of amiodarone.

Rate and rhythm therapy in patients with atrial fibrillation and the risk of pacing and bradyarrhythmia

BACKGROUND

Management of atrial fibrillation (AF) with rate and rhythm therapy can cause bradyarrhythmia.

OBJECTIVES

To assess overall risk, temporal risk, and subgroup at risk of bradyarrhythmia-related events by rate and/or rhythm therapy drugs.

METHODS

Using Danish nationwide registries, patients with AF between 2000 and 2014 were included if prescribed with rate-lowering drugs (RLDs) or antiarrhythmic drugs (AADs). An adjusted time-dependent Poisson regression model estimated the association between RLDs and AADs with a composite endpoint of pacemaker, temporary pacing, and bradyarrhythmia hospitalization. Secondary outcomes were each individual event.

RESULTS

Among 135,017 AF patients, 9196 (6.8%) patients experienced the composite endpoint with a median follow-up of 3.7 (interquartile range [IQR]: 1.6-7.0) years. Median age was 74 (IQR: 65-82) years and 47.6% were women. With rate-lowering monotherapy as the reference, the incidence rate ratios (IRR) (95% confidence interval) for the composite endpoint were 1.36 (1.29-1.43) for rate-lowering dual therapy, 1.62 (1.43-1.84) for antiarrhythmic monotherapy, and 2.49 (2.29-2.71) for AAD combined with RLDs. Similar trend was found for each secondary outcome. Particularly amiodarone increased the risk. This association was strongest within the first 2 weeks of treatment. In those treated with AAD combined with RLDs, high-risk populations were patients ≥70 years (IRR: 3.35 [2.51-4.45] compared to patients <60 years), and women (IRR: 1.35 [1.15-1.57], compared to men).

CONCLUSIONS

In real-world AF patients, rate-lowering dual therapy, antiarrhythmic monotherapy, and AADs combined with RLDs were positively associated with bradyarrhythmia-related events. The risk was highest in those treated with amiodarone, in the initial 2 weeks of treatment, in women, and in the elderly.

Anti-arrhythmic drug therapy in implantable cardioverter-defibrillator recipients

Implantable cardioverter-defibrillators (ICDs) have revolutionized the primary and secondary prevention of patients with ventricular arrhythmias. However, the adverse effects of appropriate or inappropriate shocks may require the adjunctive use of anti-arrhythmic drugs (AADs). Beta blockers are the cornerstone of pharmacological primary and secondary prevention of ventricular arrhythmias. In addition to their established efficacy at reducing the incidence of ventricular arrhythmias, beta-blockers are safe with few side effects. Amiodarone is superior to beta blockers and sotalol for the prevention of ventricular arrhythmia recurrence. However, long-term amiodarone use is associated with significant side effects that limit its utility. Sotalol and mexiletine are the main alternatives to amiodarone with a better side effect profile though they are less efficacious at preventing ventricular arrhythmia recurrence. Dofetilide, azimilide and ranolazine are emerging as therapeutic options for secondary prevention; more studies are needed to assess efficacy and safety in comparison to currently used agents. Beta blockers and amiodarone are the mainstay of therapy in patients experiencing electrical storm; their use reduces the frequency of ventricular arrhythmias and ICD intervention as well as affording time until catheter ablation can be considered.

Cardiac implantable electrical devices in women

Clinical trials have demonstrated the benefits of cardiac implantable electrical devices, which include pacemakers, implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT), with respect to key clinical outcomes and survival. Women more often require permanent pacing for sick sinus syndrome, whereas atrioventricular block is more common in men. Women appear to have a higher incidence of complications with pacemaker implantation, as well as with ICD and CRT implantation. The indications for ICDs and CRT do not have any distinctions based on sex, and outcomes are comparable in men and women. In fact, women often seem to have better outcomes with CRT compared with men. Despite the demonstrated benefits of these devices, ICDs and CRT are underutilized in women. In this review, we explore sex differences in utilization, outcomes, and complications with pacemakers, ICDs, and CRT.

Gender and AF: Differences and Disparities

AF is the most common clinical arrhythmia encountered. A wealth of evidence has improved our ability to diagnose and effectively treat AF. An intriguing aspect of this common disease – gender-based differences – is well recognized, but poorly understood. In this brief review, we will explore the accumulating evidence suggesting a gender-based disparity in the prevalence, pathogenesis and management of AF.

Gender-based personalized pharmacotherapy: a systematic review

PURPOSE

In general, male and female are prescribed the same amount of dosage even if most of the cases female required less dosage than male. Physicians are often facing problem on appropriate drug dosing, efficient treatment, and drug safety for a female in general. To identify and synthesize evidence about the effectiveness of gender-based therapy; provide the information to patients, providers, and health system intervention to ensure safety treatment; and minimize adverse effects.

METHODS

We performed a systematic review to evaluate the effect of gender difference on pharmacotherapy. Published articles from January 1990 to December 2015 were identified using specific term in MEDLINE (PubMed), EMBASE, and the Cochrane library according to search strategies that strengthen the reporting of observational and clinical studies.

RESULTS

Twenty-six studies fulfilled the inclusion criteria for this systematic review, yielding a total of 6309 subjects. We observed that female generally has a lower the gastric emptying time, gastric PH, lean body mass, and higher plasma volume, BMI, body fat, as well as reduce hepatic clearance, difference in activity of Cytochrome P450 enzyme, and metabolize drugs at different rate compared with male. Other significant factors such as conjugation, protein binding, absorption, and the renal elimination could not be ignored. However, these differences can lead to adverse effects in female especially for the pregnant, post-menopausal, and elderly women.

CONCLUSION

This systematic review provides an evidence for the effectiveness of dosage difference to ensure safety and efficient treatment. Future studies on the current topic are, therefore, recommended to reduce the adverse effect of therapy.

Effects of Adequate Iodine Supply on the Incidence of Iodine-Induced Thyroid Disorders in Slovenia

BACKGROUND

This study aimed to establish the changes in the incidence and characteristics of iodine-induced hyperthyroidism (II-Hyper) and iodine-induced hypothyroidism (II-Hypo) in the two-year period before and the 10-year period after the increase in mandatory salt iodization from the previous 10 mg/kg of potassium iodide to 25 mg/kg in 1999. Furthermore, the aim was to determine the duration of treatment in II-Hyper patients, since no data regarding severity and treatment of II-Hyper with respect to iodine supply are available.

METHODS

This retrospective study reviewed medical records of 885 Slovenian patients first diagnosed with II-Hyper or II-Hypo between 1998 and 2009 at the Thyroid Department of the University Medical Centre Ljubljana. II-Hyper and II-Hypo were diagnosed by one out of 10 senior internal medicine specialists. The diagnosis was based on an adequate patient history, and laboratory measurements of thyrotropin, thyroid hormones, and thyroid antibodies. In most cases, thyroid ultrasound and thyroid scintigraphy were performed. Demographic characteristics and the type and the duration of treatment were also reviewed.

RESULTS

The incidence of II-Hypo was significantly higher after the increase in iodine supply than it was before (p < 0.001). After the increase in iodine supply, the incidence of II-Hyper was significantly lower than before the increase (p < 0.001). Furthermore, the portion of patients with overt hyperthyroidism decreased, predominantly due to the increased proportion of patients with subclinical hyperthyroidism (p = 0.007 and p = 0.015, respectively). The duration of treatment with antithyroid drugs and perchlorate was significantly shorter after the increase in iodine supply than it was before (p = 0.001 and p = 0.002, respectively). A significantly positive correlation between the year of the occurrence of excessive iodine intake (EII)-induced thyroid disease and the duration of treatment with amiodarone was found (R = 0.132; p = 0.048), suggesting that the longer the patients had an adequate iodine supply, the longer they could take amiodarone before EII-induced thyroid disorder developed.

CONCLUSIONS

After the increase in iodine supply, a higher incidence of II-Hypo and a lower incidence of II-Hyper were observed than before the increase. Less severe II-Hyper, shorter duration of treatment of II-Hyper, as well as a longer thyroid disease-free period in patients on amiodarone are additional beneficial clinical consequences after the establishment of an adequate iodine supply.

To use or not to use? Amiodarone before heart transplantation

BACKGROUND

Amiodarone frequently is used in patients with heart failure. Concerns still exist about possible complications related to its lingering effect during and after heart transplantation.

METHODS

We selected all consecutive patients who received a heart transplant at our institution between January 2004 and December 2015 (n = 220) and compared the peri- and postoperative outcomes of patients who were taking amiodarone for at least 120 days before heart transplant (n = 127) with patients who did not take amiodarone prior to heart transplant (n = 93).

RESULTS

Compared with patients with no amiodarone use prior to transplant, those who had used amiodarone were similar in age, body mass index, sex, cause of cardiomyopathy, prevalence of diabetes, hypertension, presence of defibrillator, and had similar donor ischemic times during transplant (all P > .05). Median operative time, aortic cross clamp time, mechanical ventilation and median hospital duration of stay did not differ between the 2 groups (P > .05). Patients exposed to amiodarone had fewer cellular rejections (5% vs 20%; P = .001) but more primary graft dysfunction (4% vs 0%; P = .025) and post-transplant pneumonia (P = .047) compared with patients not taking amiodarone prior to transplant. Both groups had similar rate of atrial fibrillation, 30-day readmission, and 30-day mortality (P > .05). Even though 1-year survival was not affected by amiodarone use (P = .51), long-term (5-year) survival was significantly less in patients exposed to amiodarone (P = .03).

CONCLUSION

Amiodarone use did not affect the incidence of atrial fibrillation nor 30-day and 1-year survival post-transplantation. Nevertheless, post-transplant pulmonary complications were significantly greater and 5-year survival was less among patients treated with amiodarone prior to transplant.

Impact of sex and ethnicity on arrhythmic risk

Substantial differences in the risk of common arrhythmia syndromes exist between men and women, as well as in varying ethnic/racial groups. For example, despite an overall lower risk of sudden death and atrial fibrillation in women compared with men, women have longer QT intervals and a higher risk of torsades de pointes due to antiarrhythmic drugs and worse outcomes associated with atrial fibrillation. An ethnicity-related paradox in atrial fibrillation epidemiology is apparent; despite a higher prevalence of medical comorbidities such as hypertension, diabetes, and prolonged PR interval, blacks, Hispanics, and Asians have a lower risk of atrial fibrillation than whites. In this promising era of genomic medicine, an improved understanding of epidemiology and phenotype holds the potential for revealing novel therapeutic targets and preventing disease.

The influence of cholinesterase inhibitor therapy for dementia on risk of cardiac pacemaker insertion: a retrospective, population-based, health administrative databases study in Ontario, Canada

BACKGROUND

Cholinesterase inhibitors are used to treat the symptoms of dementia and can theoretically cause bradycardia. Previous studies suggest that patients taking these medications have an increased risk of undergoing pacemaker insertion. Since these drugs have a marginal impact on patient outcomes, it might be preferable to change drug treatment rather than implant a pacemaker. This population-based study determined the association of people with dementia exposed to cholinesterase inhibitor medication and pacemaker insertion.

METHODS

We used data from the Ontario health administrative databases from January 1, 1993 to June 30, 2012. We included all community-dwelling seniors who had a code for dementia and were exposed to cholinesterase inhibitors (donezepil, galantamine, and rivastigmine) and/or drugs used to treat co-morbidities of hypertension, diabetes, depression and hypothyroidism. We controlled for exposure to anti-arrhythmic drugs. Observation started at first exposure to any medication and continued until the earliest of pacemaker insertion, death, or end of study.

RESULTS

2,353,909 people were included with 96,000 (4.1%) undergoing pacemaker insertion during the observation period. Case-control analysis showed that pacemaker patients were less likely to be coded with dementia (unadjusted OR 0.42 [95%CI 0.41-0.42]) or exposed to cholinesterase inhibitors (unadjusted OR 0.39 [95%CI 0.37-0.41]). That Cohort analysis showed patients with dementia taking cholinesterase inhibitors had a decreased risk of pacemaker insertion (unadj-HR 0.58 [0.55-0.61]). Adjustment for patient age, sex, and other medications did not notably change results, as did restricting the analysis to incident users.

CONCLUSIONS

Patients taking cholinesterase inhibitors rarely undergo, and have a significantly reduced risk of, cardiac pacemaker insertion.

Sex-Based Differences in Cardiac Arrhythmias, ICD Utilisation and Cardiac Resynchronisation Therapy

Many important differences in the presentation and clinical course of cardiac arrhythmias are present between men and women that should be accounted for in clinical practice. In this paper, we review published data on gender differences in cardiac excitable properties, supraventricular tachycardias, ventricular tachycardias, sudden cardiac death, and the utilisation of implantable defibrillators and cardiac resynchronisation therapy. Women have a higher heart rate at rest, and a longer QT interval than men. They further have a narrower QRS complex and lower QRS voltages on the 12-lead ECG with more often non-specific repolarisation abnormalities at rest. Supraventricular tachycardias, such as AV nodal reentrant tachycardia, are twice as frequent in women compared with men. Atrial fibrillation, however, has a 1.5-fold higher prevalence in men. The triggers for idiopathic right ventricular outflow tract tachycardia (VT) initiation are gender specific, i.e. hormonal changes play an important role in the occurrence of these VTs in women. There are clear-cut gender differences in acquired and congenital LQTS. Brugada syndrome affects men more commonly and severely than women. Sudden cardiac death is less prevalent in women at all ages and occurs 10 years later in women than in men. This may be related to the later onset of clinically manifest coronary heart disease in women. Among patients who receive ICDs and CRT devices, women appear to be under-represented, while they may benefit even more from these novel therapies.

Sex and gender in adverse drug events, addiction, and placebo

Sex-gender-based differences in response to pharmaceutical treatments are still under evaluation but evidence already exists regarding the impact of sex-gender-related differences on drug safety profile, drug abuse/addiction, and placebo effects. For a number of drugs it is well recognized that a sex-gender dimorphic profile in terms of drug adverse effects exists and appears to be more frequent and severe in women than in men. However, it is not well known whether this is due to pharmacodynamic or pharmacokinetic differences. Indeed the optimization of therapy requires that attention is paid to single sex-gender. Numerous pharmacokinetic, pharmacodynamic, and sociocultural differences between women and men in drug abuse have been described. Here we focus on sex-gender differences in alcoholism and nicotine addiction. The relevance of sex and gender differences in addiction appear to be relevant. Specific programs aimed to address addicted women's specific needs (child care, pregnancy, housing, and violence and others) are recommended. Finally, this article discusses the possible effect of sex-gender on placebo response in the light of the more significant recent literature evidencing that studies are urgently required in order to better understand the role of sex-gender on placebo mechanism and its impact on randomized clinical trials outcomes.