Sex differences in arrhythmias

Review: Sex-related differences in the treatment of cardiac arrhythmia

Cardiac arrhythmias are a common and potentially serious cardiovascular disorders that affect both men and women. However, there is evidence to suggest that there may be sex-related differences in the prevalence, clinical presentation, and management of cardiac arrhythmias. Hormonal and cellular factors may play a role in these sex-specific differences. In addition, there are differences in the types of arrhythmias that men and women experience, with men more likely to experience ventricular arrhythmias and women more likely to experience supraventricular arrhythmias. The management of cardiac arrhythmias also differs between men and women. For example, some studies have found that women are less likely to receive appropriate treatment for arrhythmias and are more likely to have adverse outcomes following treatment. Despite these sex-related differences, the majority of research on cardiac arrhythmias has been conducted in men, and there is a need for more research to specifically examine the differences between men and women. This is especially important given that the prevalence of cardiac arrhythmia is increasing, and it is essential to understand how to effectively diagnose and treat these conditions in both men and women. In this review, we examine the current understanding of sex-related differences in cardiac arrhythmias. We also review the available data on sex-specific management strategies for cardiac arrhythmias and highlight areas of future research.

Higher Na+-Ca2+ Exchanger Function and Triggered Activity Contribute to Male Predisposition to Atrial Fibrillation

Male sex is one of the most important risk factors of atrial fibrillation (AF), with the incidence in men being almost double that in women. However, the reasons for this sex difference are unknown. Accordingly, in this study, we sought to determine whether there are sex differences in intracellular Ca2+ homeostasis in mouse atrial myocytes that might help explain male predisposition to AF. AF susceptibility was assessed in male (M) and female (F) mice (4–5 months old) using programmed electrical stimulation (EPS) protocols. Males were 50% more likely to develop AF. The Ca2+ transient amplitude was 28% higher in male atrial myocytes. Spontaneous systolic and diastolic Ca2+ releases, which are known sources of triggered activity, were significantly more frequent in males than females. The time to 90% decay of Ca2+ transient was faster in males. Males had 54% higher Na+-Ca2+ exchanger (NCX1) current density, and its expression was also more abundant. L-type Ca2+ current (ICaL) was recorded with and without BAPTA, a Ca2+ chelator. ICaL density was lower in males only in the absence of BAPTA, suggesting stronger Ca2+-dependent inactivation in males. CaV1.2 expression was similar between sexes. This study reports major sex differences in Ca2+ homeostasis in mouse atria, with larger Ca2+ transients and enhanced NCX1 function and expression in males resulting in more spontaneous Ca2+ releases. These sex differences may contribute to male susceptibility to AF by promoting triggered activity.

Gender associated disparities in atrioventricular nodal reentrant tachycardia: A review article

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common sustained supraventricular arrhythmias. An understanding of gender-related differences in AVNRT epidemiology, diagnosis, treatment, outcome, and complications can help guide a more effective diagnosis and treatment of the condition. The study aimed to perform a review of the available literature regarding all aspects of gender-related differences of AVNRT. We focused on all aspects of gender-related differences regarding AVNRT between men and women. A literature search was performed using Google Scholar, PubMed, Springer, Ovid, and Science Direct. Many investigations have demonstrated that the prevalence of AVNRT exhibited a twofold women-to-men predominance. The potential mechanism behind this difference due to sex hormones and autonomic tone. Despite being more common in women, there is a delay in offering and performing the first-line therapy (catheter ablation) compared to men. There were no significant gender-related discrepancies in patients who underwent ablation therapy for AVNRT, regarding the acute success rate of the procedure, long-term success rate, and recurrence of AVNRT. AVNRT is more common in women due to physiological factors such as sex hormones and autonomic tone. Catheter ablation is equally safe and efficacious in men and women; however, the time between the onset of symptoms and ablation is significantly prolonged in women. It is important for the medical community to be aware of this discrepancy and to strive to eliminate such disparities that are not related to patients' choices.

Plasma total testosterone and risk of incident atrial fibrillation: The Atherosclerosis Risk in Communities (ARIC) study

OBJECTIVE

Whether endogenous testosterone concentrations are associated with atrial fibrillation (AF) development is not well established. We assessed the association between plasma total testosterone concentrations and incident AF in a population-based longitudinal study.

STUDY DESIGN

Using data from the prospective Atherosclerosis Risk in Communities (ARIC) study, we identified incident AF among 9282 participants who had plasma total testosterone measured by liquid chromatography tandem mass spectrometry at Visit 4 (1996-1998).

MAIN OUTCOME MEASURES

AF cases were identified by electrocardiograms performed during study visits, hospital records/discharge codes, and death certificates through 2013. We estimated hazard ratios (HRs) and 95% confidence intervals (95% CIs) for incident AF across quartiles of plasma total testosterone, stratified by sex, with multivariable Cox models.

RESULTS

The mean age of the participant sample at ARIC Visit 4 was 63 years (range 52-75); 54.5% were women. Mean (SD) plasma total testosterone levels were 537 ng/dL (213) for men and 27.6 ng/dL (34.7) for women. Over a mean of 13.7 years of follow-up, 1664 incident cases of AF were identified. Comparing those in the highest quartile of plasma total testosterone concentration to those in the lowest quartile and after adjustment for potential confounding variables, there was a positive association between plasma total testosterone and incident AF in men (HR 1.33, 95% CI 1.07, 1.66), but no such association in women (HR 0.99, 95% CI 0.80, 1.22). Conclusion A higher plasma total testosterone concentration was associated with a modestly greater incidence rate of AF in men.

The effects of gender on electrical therapies for the heart: physiology, epidemiology, and access to therapies

The difference between men and women is clear even just by looking at an electrocardiogram: females present higher resting heart rate, a shorter QRS complex length and greater corrected QT interval. The development of these differences from pubertal age onward suggests that sexual hormones play a key role, although their effect is far from being completely understood. Different incidences between sexes have been reported for many arrhythmias, both ventricular and supraventricular, and also for sudden cardiac death. Moreover, arrhythmias are an important issue during pregnancy, both for diagnosis and treatment. Interestingly, cardiovascular structural and electrophysiological remodelling promoted by exercise training enhances this 'gender effect'. Despite all these relevant issues, we lack gender specific recommendations in the current guidelines for electrical therapies for heart rhythm disorders and heart failure. Even more, we continue to see that fewer women are included in clinical trials and are less referred than men for these treatments.

Vasomotor hot flashes and cardiac repolarization: a randomized placebo-controlled trial of postmenopausal hormone therapy

OBJECTIVE

The aim of the study was to compare the effects of different hormone therapies on cardiac repolarization in recently postmenopausal women with and without hot flashes.

METHODS

We recruited 150 healthy women: 72 with and 78 without hot flashes. They were randomized and treated for 6 months with transdermal estradiol (1 mg/day), oral estradiol (OE) alone (2 mg/day) or combined with medroxyprogesterone acetate (MPA; 5 mg/day), or placebo. Cardiac repolarization was assessed by measuring QT intervals, rate-dependence of QT-end interval, and T waves from 24-hour electrocardiographic recording before and during hormone therapy, comprising a total of over 20 million QT-interval measurements.

RESULTS

Hot flashes were accompanied with shortened median T-peak - T-end interval (at RR interval of 700, 800, and 900 ms; P = 0.040, 0.020, and 0.032; η = 0.35, 0.39, and 0.37; respectively) during the use of OE but not transdermal estradiol. In contrast, the addition of MPA to OE lengthened the maximal QT-end (at RR interval of 500 ms, P = 0.016, η = 0.27) and the maximal T-peak - T-end interval (at RR interval of 500 and 600 ms; P = 0.016 and 0.032; η = 0.25 and 0.22, respectively). These effects were not seen in women without hot flashes.

CONCLUSIONS

Hot flashes predict beneficial shortening in cardiac repolarization during OE, but not if MPA is combined with OE. These data may provide one explanation for MPA-related cardiac hazards in epidemiological studies.

Increased risk of ventricular tachycardia and cardiovascular death in patients with myocarditis during the long-term follow-up: A national representative cohort from the National Health Insurance Research Database

The incidence of acute myocarditis complicated with ventricular tachycardia (VT) is unknown. This study aimed to investigate the association between myocarditis and the incidence of VT and mortality. We also aimed to determine the independent predictors that increased the VT risk in those patients. From 2000 to 2004, 13,250 patients with a history of myocarditis were identified from the Taiwan National Health Insurance Research Database. The same number of individuals without heart disease with a matched sex and underlying diseases were selected as the control group. The long-term risks of life-threatening ventricular arrhythmias and mortality in patients with a history of myocarditis were investigated by an adjusted Cox proportional hazards regression. After a mean follow-up of 10.4 ± 2.94 years (interquartile range: 12, 10.19-12), the myocarditis patients showed a higher incidence of new onset VT events compared with healthy controls (5.4% [519 per 100,000 person-year] in the myocarditis group vs, 0.47% [43 per 100,000 person-year] in the healthy controls; adjusted hazard ratio [HR]: 16.1, 95% confidence interval [CI]: 12.4-20.9; P < .001). A higher incidence of cardiovascular death was noted in the myocarditis group than healthy controls (6.52% vs 3.18%; HR: 2.42, 95% CI: 2.14-2.73; P < .001) after adjusting for the multivariate confounders including sex, age, underlying comorbidities, and medications. The results of this study suggested that there was higher incidence of life-threatening VT and mortality during the very long-term follow-up in patients with a history of myocarditis. Future work should focus on an in-depth risk stratification of VT in myocarditis patients.

Long-Term Clinical Outcome of Arrhythmogenic Right Ventricular Cardiomyopathy in Individuals With a p.S358L Mutation in TMEM43 Following Implantable Cardioverter Defibrillator Therapy

Background—

We previously showed a survival benefit of the implantable cardioverter defibrillator (ICD) in males with arrhythmogenic right ventricular cardiomyopathy caused by a p.S358L mutation in TMEM43 . We present long-term data (median follow-up 8.5years) after ICD for primary (PP) and secondary prophylaxis in males and females, determine whether ICD discharges for ventricular tachycardia/ventricular fibrillation were equivalent to an aborted death, and assess relevant clinical predictors.

Methods and Results—

We studied 24 multiplex families segregating an autosomal dominant p.S358L mutation in TMEM43 . We compared survival in 148 mutation carriers with an ICD to 148 controls matched for age, sex, disease status, and family. Of 80 male mutation carriers with ICDs (median age at implantation 31 years), 61 (76%) were for PP; of 68 females (median age at implantation 43 years), 66 (97%) were for PP. In males, irrespective of indication, survival was better in the ICD groups compared with control groups (relative risk 9.3 [95% confidence interval 3.3–26] for PP and 9.7 [95% confidence interval 3.2–29.6] for secondary prophylaxis). For PP females, the relative risk was 3.6 (95% confidence interval 1.3–9.5). ICD discharge-free survival for ventricular tachycardia/ventricular fibrillation ≥240 beats per minute was equivalent to the control survival rate. Ectopy (≥1000 premature ventricular complexes/24 hours) was the only independent clinical predictor of ICD discharge in males, and no predictor was identified in females.

Conclusions—

ICD therapy is indicated for PP in postpubertal males and in females ≥30 years with the p.S358L TMEM43 mutation. ICD termination of rapid ventricular tachycardia/ventricular fibrillation can reasonably be considered an aborted death.

Electro-mechanical dysfunction in long QT syndrome: Role for arrhythmogenic risk prediction and modulation by sex and sex hormones

Long QT syndrome (LQTS) is a congenital arrhythmogenic channelopathy characterized by impaired cardiac repolarization. Increasing evidence supports the notion that LQTS is not purely an "electrical" disease but rather an "electro-mechanical" disease with regionally heterogeneously impaired electrical and mechanical cardiac function. In the first part, this article reviews current knowledge on electro-mechanical (dys)function in LQTS, clinical consequences of the observed electro-mechanical dysfunction, and potential underlying mechanisms. Since several novel imaging techniques - Strain Echocardiography (SE) and Magnetic Resonance Tissue Phase Mapping (TPM) - are applied in clinical and experimental settings to assess the (regional) mechanical function, advantages of these non-invasive techniques and their feasibility in the clinical routine are particularly highlighted. The second part provides novel insights into sex differences and sex hormone effects on electro-mechanical cardiac function in a transgenic LQT2 rabbit model. Here we demonstrate that female LQT2 rabbits exhibit a prolonged time to diastolic peak - as marker for contraction duration and early relaxation - compared to males. Chronic estradiol-treatment enhances these differences in time to diastolic peak even more and additionally increases the risk for ventricular arrhythmia. Importantly, time to diastolic peak is particularly prolonged in rabbits exhibiting ventricular arrhythmia - regardless of hormone treatment - contrasting with a lack of differences in QT duration between symptomatic and asymptomatic LQT2 rabbits. This indicates the potential added value of the assessment of mechanical dysfunction in future risk stratification of LQTS patients.

Estrogen regulation of the transient outward K(+) current involves estrogen receptor α in mouse heart

BACKGROUND AND OBJECTIVE

We have previously shown that androgens upregulate cardiac K(+) channels and shorten repolarization. However, the effects that estrogens (E2) and estrogen receptors (ER) might have on the various repolarizing K(+) currents and underlying ion channels remain incompletely understood. Accordingly, our objective was to verify whether and how E2 and its ERs subtypes influence these K(+) currents.

METHODS AND RESULTS

In order to examine the influence of E2 and ERs on K(+) currents we drastically lowered the E2 level through ovariectomy (OVX; 74% reduction vs CTL) and in parallel, we used female mice lacking either ERα (ERαKO) or ERβ (ERβKO). In OVX mice, results showed a specific increase of 35% in the density of the Ca(2+)-independent transient outward K(+) current (Ito) compared to CTL. Western blots showed increase in Kv4.2 and Kv4.3 sarcolemmal protein expression while qPCR revealed higher mRNA expression of only Kv4.3 in OVX mice. This upregulation of Ito was correlated with a shorter ventricular action potential duration and QTc interval. In ERαKO but not ERβKO mice, the mRNA of Kv4.3 was selectively increased. Furthermore, when ventricular myocytes obtained from ERαKO and ERβKO were cultured in the presence of E2, results showed that E2 reduced Ito density only in ERβKO myocytes confirming the repressive role of E2-ERα in regulating Ito.

CONCLUSION

Altogether, these results suggest that E2 negatively regulates the density of Ito through ERα, this highlights a potential role for this female hormone and its α-subtype receptor in modulating cardiac electrical activity.

Genetic analysis, in silico prediction, and family segregation in long QT syndrome

The heritable cardiovascular disorder long QT syndrome (LQTS), characterized by prolongation of the QT interval on electrocardiogram, carries a high risk of sudden cardiac death. We sought to add new data to the existing knowledge of genetic mutations contributing to LQTS to both expand our understanding of its genetic basis and assess the value of genetic testing in clinical decision-making. Direct sequencing of the five major contributing genes, KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2, was performed in a cohort of 115 non-related LQTS patients. Pathogenicity of the variants was analyzed using family segregation, allele frequency from public databases, conservation analysis, and Condel and Provean in silico predictors. Phenotype-genotype correlations were analyzed statistically. Sequencing identified 36 previously described and 18 novel mutations. In 51.3% of the index cases, mutations were found, mostly in KCNQ1, KCNH2, and SCN5A; 5.2% of cases had multiple mutations. Pathogenicity analysis revealed 39 mutations as likely pathogenic, 12 as VUS, and 3 as non-pathogenic. Clinical analysis revealed that 75.6% of patients with QTc≥500 ms were genetically confirmed. Our results support the use of genetic testing of KCNQ1, KCNH2, and SCN5A as part of the diagnosis of LQTS and to help identify relatives at risk of SCD. Further, the genetic tools appear more valuable as disease severity increases. However, the identification of genetic variations in the clinical investigation of single patients using bioinformatic tools can produce erroneous conclusions regarding pathogenicity. Therefore segregation studies are key to determining causality.

Scar tissue and microvolt T-wave alternans

Microvolt T-wave alternans (MTWA) is an electrocardiographic marker for predicting sudden cardiac death. In this study, we aimed to study the relation between MTWA and scar assessed with cardiac magnetic resonance imaging (CMR) in patients with ischemic cardiomyopathy (ICM) or dilated cardiomyopathy (DCM). Sixty-eight patients with positive or negative MTWA and analysable CMR examination were included. Using CMR and the delayed enhancement technique, left ventricular ejection fraction (LVEF), volumes, wall motion and scar characteristics were assessed. Overall, positive MTWA (n = 40) was related to male gender (p = 0.04), lower LVEF (p = 0.04) and increased left ventricular end-diastolic volume (LVEDV) (p < 0.01). After multivariate analysis, male gender (p = 0.01) and lower LVEF remained significant (p = 0.02). Scar characteristics (presence, transmurality, and scar score) were not related to MTWA (all p > 0.5). In the patients with ICM (n = 40) scar was detected in 38. Positive MTWA (n = 18) was related to higher LVEDV (p = 0.05). In patients with DCM (n = 28), scar was detected in 11. Trends were found between positive MTWA (n = 15) and male gender (p = 0.10), lower LVEF (p = 0.10), and higher LVEDV (p = 0.09). In both subgroups, the presence, transmurality or extent of scar was not related to MTWA (all p > 0.45). In this small study, neither in patients with ICM or DCM a relation was found between the occurrence of MTWA and the presence, transmurality or extent of myocardial scar. Overall there was a significant relation between heart failure remodeling parameters and positive MTWA.

Pharmacogenomics, pharmacokinetics and pharmacodynamics: interaction with biological differences between men and women

Pharmacological response depends on multiple factors and one of them is sex-gender. Data on the specific effects of sex-gender on pharmacokinetics, as well as the safety and efficacy of numerous medications, are beginning to emerge. Nevertheless, the recruitment of women for clinical research is inadequate, especially during the first phases. In general, pharmacokinetic differences between males and females are more numerous and consistent than disparities in pharmacodynamics. However, sex-gender pharmacodynamic differences are now increasingly being identified at the molecular level. It is now even becoming apparent that sex-gender influences pharmacogenomics and pharmacogenetics. Sex-related differences have been reported for several parameters, and it is consistently shown that women have a worse safety profile, with drug adverse reactions being more frequent and severe in women than in men. Overall, the pharmacological status of women is less well studied than that of men and deserves much more attention. The design of clinical and preclinical studies should have a sex-gender-based approach with the aim of tailoring therapies to an individual's needs and concerns.

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.

Prevalence of ventricular arrhythmia and its associated factors in nondialyzed chronic kidney disease patients

BACKGROUND AND OBJECTIVES

Sudden cardiac death is the most common cause of mortality in chronic kidney disease patients, and it occurs mostly due to ventricular arrhythmias. In this study, we aimed at investigating the prevalence of ventricular arrhythmia and the factors associated with its occurrence in nondialyzed chronic kidney disease patients.

DESIGN SETTING PARTICIPANTS AND MEASUREMENTS

This cross-sectional study evaluated 111 chronic kidney disease patients (estimated glomerular filtration rate 34.7±16.1 mL/min/1.73 m(2), 57±11.4 years, 60% male, 24% diabetics). Ventricular arrhythmia was assessed by 24-hour electrocardiogram. Left ventricular hypertrophy (echocardiogram), 24-hour ambulatory blood pressure monitoring, and coronary artery calcification (multi-slice computed tomography) and laboratory parameters were also evaluated.

RESULTS

Ventricular arrhythmia was found in 35% of the patients. Non-controlled hypertension was observed in 21%, absence of systolic decency in 29%, left ventricular hypertrophy in 27%, systolic dysfunction in 10%, and coronary artery calcification in 49%. Patients with ventricular arrhythmia were older (p<0.001), predominantly men (p = 0.009), had higher estimated glomerular filtration rate (p = 0.03) and hemoglobin (p = 0.005), and lower intact parathyroid hormone (p = 0.024) and triglycerides (p = 0.011) when compared to patients without ventricular arrhythmia. In addition, a higher left ventricular mass index (p = 0.002) and coronary calcium score (p = 0.002), and a lower ejection fraction (p = 0.001) were observed among patients with ventricular arrhythmia. In the multiple logistic regression analysis, aging, increased hemoglobin levels and reduced ejection fraction were independently related to the presence of ventricular arrhythmia.

CONCLUSIONS

Ventricular arrhythmia is prevalent in nondialyzed chronic kidney disease patients. Age, hemoglobin levels and ejection fraction were the factors associated with ventricular arrhythmia in these patients.

A GENS-based approach to cardiovascular pharmacology: impact on metabolism, pharmacokinetics and pharmacodynamics

Pharmacological outcomes depend on many factors, with many of them being sexually dimorphic. Thus, physiological gender/sex (GENS) differences can influence pharmacokinetics, pharmacodynamics and, thus, bioavailability and resulting in efficacy of treatment, meaning GENS differences should be an important consideration in therapeutics. In particular, drug response can change according to different hormonal environments. Therefore, GENS-specific differences have a particular clinical relevance in terms of drug delivery, especially for those substances with a narrow therapeutic margin. Since adverse effects are more frequent among women, safety is a key issue. Overall, the status of women, from a pharmacological point of view, is often different and less studied than that of men and deserves particular attention. Further studies focused on women's responses to drugs are necessary in order to make optimal pharmacotherapeutic decisions.

Vasomotor hot flashes and heart rate variability: a placebo-controlled trial of postmenopausal hormone therapy

OBJECTIVE

The aim of the study was to compare the responses of heart rate variability (HRV) with hormone therapy in recently postmenopausal women with and without vasomotor hot flashes.

METHODS

Seventy-two women with and 78 women without hot flashes were randomized to receive transdermal estradiol gel (1 g/day), oral estradiol alone (2 mg/day), oral estradiol combined with medroxyprogesterone acetate (MPA; 5 mg/day), or placebo for 6 months. Time- and frequency-domain measures of HRV were assessed using 24-hour electrocardiographic recordings at baseline and after hormone therapy.

RESULTS

At baseline, the cardiac variables were similar in women with and without hot flashes. In women with hot flashes, the mean 24-hour heart rate and nighttime heart rate showed a tendency toward reduction in estradiol-only users compared with those taking placebo and those taking estradiol combined with MPA. In women with hot flashes, oral estradiol versus transdermal estradiol reduced nighttime HRV in the time domain (triangular index, -27 ± 36 vs +8 ± 36, P = 0.042). In women without hot flashes, the use of oral estradiol with MPA reduced time-domain HRV (SD of all normal-to-normal intervals; -11 ± 13 ms, P = 0.048, and square root of the mean of the sum of the squares of differences between adjacent normal-to-normal intervals; -6 ± 8 ms, P = 0.036). The women with hot flashes had more supraventricular ectopic beats when using oral estradiol with MPA than when using oral estradiol only (71 ± 128 vs 12 ± 11, P = 0.018).

CONCLUSIONS

Oral estrogen, especially when combined with MPA, may have adverse effects on HRV in women with and without hot flashes, whereas transdermal estradiol showed no such effects. Furthermore, women with hot flashes receiving oral estrogen combined with MPA are possibly more prone to cardiac arrhythmias than are women using estrogen only.

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.

Gender and Racial Characteristics of Patients Referred to a Tertiary Atrial Fibrillation Center

Atrial Fibrillation Centers (AFCs) are becoming increasingly common and are often developed at institutions to provide comprehensive evaluation and management for patients with atrial fibrillation (AF) including catheter and surgical ablation. Studies have shown that women and racial minority patients are less likely to be offered aggressive or invasive therapies. The University of Virginia (UVA) AFC was opened in 2004. We analyzed data collected during initial visits to our AFC from 2004-2008 to determine the gender and racial characteristics of a tertiary AFC population. Multivariable regression analysis was used to compare clinical characteristics. There were a total of 1664 consecutive initial patient visits. Cardiologists referred 61% and primary care physicians referred 37% of patients. Twice as many men were referred as women (570 vs. 1094; P<0.0001). Women were older (68.0±11.9 vs. 62.4±13.0 years; P<0.0001) and more symptomatic with palpitations (80% vs. 73%; P=0.008), but otherwise were not substantially different from men. Our referring physicians treated the majority of both men and women with anticoagulant and rate-controlling medications. African American patients accounted for 2.8% of AFC initial visits. In contrast, they accounted for 7.4% of patients seen for a primary diagnosis of AF at all other UVA outpatient clinics (P<0.0001). In conclusion, the demographics of a tertiary AFC are different than those of the general population. Women and racial minority patients are underrepresented, and the women have few comorbidities and symptoms than the known epidemiology would lead us to expect.

Molecular genetics of long QT syndrome

Long QT syndrome (LQTS) is a cardiac disorder associated with sudden death especially in young, seemingly healthy individuals. It is characterised by abnormalities of the heart beat detected as lengthening of the QT interval during cardiac repolarisation. The incidence of LQTS is given as 1 in 2000 but this may be an underestimation as many cases go undiagnosed, due to the rarity of the condition and the wide spectrum of symptoms. Presently 12 genes associated with LQTS have been identified with differing signs and symptoms, depending on the locus involved. The majority of cases have mutations in the KCNQ1 (LQT1), KCNH2 (LQT2) and SCN5A (LQT3) genes. Genetic testing is increasingly used when a clearly affected proband has been identified, to determine the nature of the mutation in that family. Unfortunately tests on probands may be uninformative, especially if the defect does not lie in the set of genes which are routinely tested. Novel mutations in these known LQTS genes and additional candidate genes are still being discovered. The functional implications of these novel mutations need to be assessed before they can be accepted as being responsible for LQTS. Known epigenetic modification affecting KCNQ1 gene expression may also be involved in phenotypic variability of LQTS. Genetic diagnosis of LQTS is thus challenging. However, where a disease associated mutation is identified, molecular diagnosis can be important in guiding therapy, in family testing and in determining the cause of sudden cardiac death. New developments in technology and understanding offer increasing hope to families with this condition.

Ventricular arrhythmia in incident kidney transplant recipients: prevalence and associated factors

Cardiovascular mortality in kidney transplant recipients has shown to be substantially elevated particularly in the first year of transplantation. Complex ventricular arrhythmia (VA) has been pointed as one of the etiologies of sudden death. The aim of this study was to evaluate the prevalence of VA and to investigate the factors associated with their occurrence in incident kidney transplant recipients. A total of 100 incident kidney transplant recipients were included in the study (39.7 ± 10.1 years, 55% male, 43.6 ± 10.1 days of transplantation, 66% living donors). All the patients underwent 24 h electrocardiogram, echocardiogram and multi-slice computed tomography. Thirty percent of the patients had VA. Left ventricular hypertrophy was observed in 57% of the patients while heart failure was found in 5%. Coronary artery calcification (CAC) was observed in 26 patients, from which 31% had severe calcification. The group of patients with VA was predominantly male, had been on dialysis therapy for a longer time and had more coronary calcification. In the multiple logistic regression analysis, male gender and CAC score were independently associated with the presence of VA. In conclusion, kidney transplant recipients exhibited a high prevalence of VA and the factors associated with its occurrence were the male gender and the presence of CAC.

Androgens and atrial fibrillation: friends or foes?

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice. The prevalence of AF increases with age, and this age-specific prevalence is higher in men than in women. However, the mechanisms of aging-induced AF have not been fully elucidated, and this may be related to decline of testosterone with advancing age. On the other hand, anabolic steroid abuse may precipitate the occurrence of AF. Until now, the possible relationship between androgens and AF was not comprehensively reviewed. We intend to review some recent evidence on this issue and propose some potential mechanisms.