The association of serum testosterone levels and ventricular repolarization

QTc prolongation in patients with schizophrenia taking antipsychotics: Prevalence and risk factors

BACKGROUND

QTc prolongation is one of the possible complications in patients with schizophrenia taking antipsychotics, which leads to malignant cardiac arrhythmia. No meta-analysis has been reported assessing the prevalence and correlated risk factors for QTc prolongation.

METHODS

This meta-analysis aimed to assess the evidence for the prevalence of QTc prolongation and correlated risk factors in patients with schizophrenia taking antipsychotics. Web of Science and PubMed were searched according to preset strategy. The quality of research was assessed by the Newcastle-Ottawa Scale (NOS).

RESULTS

In all, 15 studies covering 15,540 patients with schizophrenia taking antipsychotics were included. Meta-analysis showed that the prevalence of QTc prolongation in patients with schizophrenia taking antipsychotics was about 4.0% (95% confidence interval (CI): 3.0%-5.0%, p < 0.001). The prevalence was about 4.0% in Asia (95%CI: 3.0%-6.0%, p < 0.001), about 5.0% in Europe (95%CI: 2.0%-7.0%, p < 0.001), and about 2.0% in America (95%CI: 1.0%-3.0%, p < 0.001). Sensitivity analyses indicated the robustness of the result. Publication bias analysis reported a certain publication bias (t = 3.37, p = 0.012). Meta-regression suggested that female and elderly patients were clinically associated with a higher prevalence of QTc prolongation. According to included studies, smoking, comorbidity of cardiovascular disease, and abnormal levels of high-density lipoprotein/low-density lipoprotein might be related to QTc prolongation in patients with schizophrenia taking antipsychotics.

CONCLUSIONS

The prevalence of QTc prolongation in patients with schizophrenia taking antipsychotics was about 4.0%. Female and elderly patients were more likely to experience QTc prolongation. Close electrocardiogram monitoring was suggested in these at-risk populations.

Artificial Intelligence-Augmented Electrocardiogram in Determining Sex: Correlation with Sex Hormone Levels

OBJECTIVE

To study the relationship between the sex probability derived from the artificial intelligence (AI)-augmented electrocardiogram (ECG) and sex hormone levels.

PATIENTS AND METHODS

Adult patients with total testosterone (TT; ng/dL) or estradiol (E2; pg/mL) levels (January 1, 2000, to December 31, 2020) with ECGs obtained within 6 months of the blood sample were identified. The closest ECG to the blood test was used. The AI-ECG model output ranges from 0.0 to 1.0, with higher numbers indicating high probability of being male. Low male probability was defined as ≤0.3, intermediate as 0.31 to 0.69, and high as ≥0.7. Continuous variables are expressed as median (interquartile range).

RESULTS

Paired TT-ECGs were available in 58,084 male subjects and 11,190 female subjects. Paired E2-ECGs were available in 2835 male patients and 18,228 female patients. TT levels had moderate positive correlation with AI-ECG male sex probability (r=0.46, P<.001). Male subjects with low AI-ECG male sex probability had lower TT and higher E2 levels compared with men with high probability (TT: 303 [129-474] vs 381 [264-523], P <.001; E2: 35 [21-49] vs 32 [22-38], P=.05). Female subjects with high AI-ECG male sex probability had higher TT and lower E2 levels compared with those who had low male probability (TT: ≤50 years of age: 31 [18-55] vs 26 [16-39], P<.001; >50 years of age: 27 [12-68] vs 20 [12-34], P<.001; E2: ≤50 years of age: 58 [30-124] vs 47 [25-87], P=.001; >50 years of age: 30 [10-55] vs 21 [10-41], P=.006).

CONCLUSION

In this study, TT levels were lower and E2 levels higher with decreasing AI-ECG male probability in both sexes. Male and female patients with discordant AI-ECG sex probability had significantly different TT or E2 levels. This suggests that the ECG could be used as a biomarker of hormone status.

Artificial Intelligence Application in Graves Disease: Atrial Fibrillation, Heart Failure and Menstrual Changes

OBJECTIVE

To study the utility of artificial intelligence (AI)-enabled electrocardiograms (ECGs) in patients with Graves disease (GD) in identifying patients at high risk of atrial fibrillation (AF) and heart failure with reduced ejection fraction (HFrEF), and to study whether AI-ECG can reflect hormonal changes and the resulting menstrual changes in GD.

PATIENTS AND METHODS

Patients diagnosed with GD between January 1, 2009, and December 31, 2019, were included. We considered AF diagnosed at 30 days or fewer before or any time after GD and de novo HFrEF not explained by ischemia, valve disorder, or other cardiomyopathy at/after GD diagnosis. Electrocardiograms at/after index condition were excluded. A subset analysis included females younger than 45 years of age to study the association between ECG-derived female probability and menstrual changes (shorter, lighter, or newly irregular cycles).

RESULTS

Among 430 patients (mean age, 50±17 years; 337 (78.4%) female), independent risk factors for AF included ECG probability of AF (hazard ratio [HR], 1.5; 95% CI, 1.2 to 1.6 per 10%; P<.001), older age (HR, 1.05; 95% CI, 1.03 to 1.07 per year; P<.001), and overt hyperthyroidism (HR, 3.9; 95% CI, 1.2 to 12.7; P=.03). The C-statistic was 0.85 for the combined model. Among 495 patients (mean age, 52±17 years; 374 (75.6%) female), independent risk factors for HFrEF were ECG probability of low ejection fraction (HR, 1.4; 95% CI, 1.1 to 1.6 per 10%; P=.001) and presence of AF (HR, 8.3; 95% CI, 2.2 to 30.9; P=.002), and a C-statistic of 0.89 for the combined model. Lastly, of 72 females younger than 45 years, 30 had menstrual changes at time of GD and had a significantly lower AI ECG-derived female probability [median 77.3; (IQR 57.9 to 94.4)% vs. median 97.7 (IQR 92.4 to 99.5)%, P<.001].

CONCLUSION

AI-enabled ECG identifies patients at risk for GD-related AF and HFrEF and was associated with menstrual changes in women with GD.

Drug-Associated QTc Prolongation in Geriatric Hospitalized Patients: A Cross-Sectional Study in Internal Medicine

Objective

The primary objectives of this prospective cross-sectional study were to estimate the prevalence of drug-related long QT syndrome (LQTS) and the prevalence of use of QT-prolonging drugs in older patients admitted to an internal medicine unit.

Methods

We screened consecutive patients hospitalized in an internal medicine unit over a 2-year period. A 12-lead electrocardiogram using an electrocardiograph with automated measurement of QT interval was recorded. Patient characteristics (age, sex, body mass index), drug treatments, and variables associated with QT interval prolongation, including hypothyroidism, type 2 diabetes mellitus, and cardiac disease, were also recorded. In addition, we also measured serum levels of potassium, calcium, magnesium, and creatinine at admission. The list of medications known to cause or to contribute to LQTS was obtained from CredibleMeds^®.

Results

A total of 243 patients were enrolled: mean ± standard deviation age, 79.65 ± 8.27 years; males, n = 121 (40.8%); mean corrected QT (QTc) interval, 453.70 ± 43.77 ms. Overall, 89/243 (36.6%) patients had a prolonged QTc interval, with 29/243 (11.9%) having QTc interval prolongation > 500 ms (11.9%). A vast majority were prescribed at least one QT-prolonging drug (218/243 [89.7%]), whereas 74/218 (30.5%) were receiving at least one medication with a known risk of Torsades des Pointes (TdP). Proton pump inhibitors were the second most commonly prescribed class of drugs. After logistic regression, male sex was independently associated with LQTS (odds ratio 2.85; 95% confidence interval 1.56–5.22; p = 0.001).

Conclusions

The prevalence of LQTS with QTc interval > 500 ms in geriatric inpatients was > 10%, and QT-prolonging drugs were frequently used on admission (more than 30% of patients were receiving drugs with a known risk of TdP).

Supplementary Information

The online version contains supplementary material available at 10.1007/s40801-021-00234-x.

Changes in left ventricular repolarization after short-term testosterone replacement therapy in hypogonadal males

BACKGROUND AND AIM

Evidences suggest that androgen deficiency is associated with sudden cardiac death (SCD). Our purpose was to analyse some electrocardiographic (ECG) markers of repolarization phase in hypogonadal patients either at baseline or after testosterone replacement therapy (TRT).

PATIENTS AND METHODS

Baseline and after 6 months of testosterone replacement therapy, 14 hypogonadal patients and 10 age-matched controls underwent a short-term ECG recordings at rest and immediately after a maximal exercise test. The following ECG parameters have been collected: QTe (the interval between the q wave the end of T wave), QTp (the interval between the q wave and the peak of T wave), and Te (the interval between the peak and the end of T wave).

RESULTS

At baseline, in the hypogonadal patients, corrected QTe and QTp values were longer at rest than in the controls at rest (p < 0.05), whereas, during the recovery phase, only the QTp remained significantly longer (p < 0.05). After TRT, hypogonadal patients showed an improvement only in Te (p < 0.05). Conversely, any difference between hypogonadal patients and control subjects was found with respect to the markers of temporal dispersion of repolarization phases, except for a worse QTp → Te coherence (p = 0.001) obtained during the recovery phase.

CONCLUSIONS

In conclusion, at rest, hypogonadal patients suffer from a stable increase in the myocardial repolarization phase without an increase in its temporal dispersion and, hence, the SCD risk seems to be low.

Age and Sex Estimation Using Artificial Intelligence From Standard 12-Lead ECGs

Supplemental Digital Content is available in the text.

Sex and age have long been known to affect the ECG. Several biologic variables and anatomic factors may contribute to sex and age-related differences on the ECG. We hypothesized that a convolutional neural network (CNN) could be trained through a process called deep learning to predict a person’s age and self-reported sex using only 12-lead ECG signals. We further hypothesized that discrepancies between CNN-predicted age and chronological age may serve as a physiological measure of health.

Testosterone, myocardial function, and mortality

The cardiovascular system is particularly sensitive to androgens, but some controversies exist regarding the effect of testosterone on the heart. While among anabolic abusers, cases of sudden cardiac death have been described, recently it was reported that low serum level of testosterone was correlated with increased risk of cardiovascular diseases (CVD) and mortality rate. This review aims to evaluate the effect of testosterone on myocardial tissue function, coronary artery disease (CAD), and death. Low testosterone level is associated with increased incidence of CAD and mortality. Testosterone administration in hypogonadal elderly men and women has a positive effect on cardiovascular function and improved clinical outcomes and survival time. Although at supraphysiologic doses, androgen may have a toxic effect, and at physiological levels, testosterone is safe and exerts a beneficial effect on myocardial function including mechanisms at cellular and mitochondrial level. The interaction with free testosterone and estradiol should be considered. Further studies are necessary to better understand the interaction mechanisms for an optimal androgen therapy in CVD.

Androgen Deprivation Therapy Is Associated With Prolongation of QTc Interval in Men With Prostate Cancer

CONTEXT

Androgen deprivation therapy (ADT) for prostate cancer (PCa) is associated with increased cardiovascular mortality and sudden cardiac death, with some events occurring early after initiation of ADT. Testosterone levels are inversely associated with corrected QT (QTc) interval duration; therefore, prolongation of QTc duration could be responsible for some of these events during ADT.

OBJECTIVE

To evaluate changes in QTc duration during ADT.

DESIGN AND INTERVENTIONS

A 6-month prospective cohort study that enrolled men with PCa about to undergo ADT (ADT group) and a control group of men who previously underwent prostatectomy for PCa and never received ADT (non-ADT group).

PATIENTS

At study entry, all participants were eugonadal and had no history of cardiac arrhythmias or complete bundle branch block.

OUTCOMES

Difference in change in QTc duration from baseline on a 12-lead electrocardiogram at 6, 12, and 24 weeks after initiation of ADT compared with electrocardiograms performed at the same intervals in the non-ADT group. PR, QRS, and QT interval durations were also evaluated.

RESULTS

Seventy-one participants formed the analytical sample (33 ADT and 38 non-ADT). ADT was associated with prolongation of the QTc by 7.4 ms compared with the non-ADT group [95% confidence interval (CI) 0.08 to 14.7 ms; P = 0.048]. ADT was also associated with shortening of the QRS interval by 2.4 ms (95% CI -4.64 to -0.23; P = 0.031). Electrolytes did not change.

CONCLUSIONS

Men undergoing ADT for PCa experienced prolongation of the QTc. These findings might explain the increased risk of sudden cardiac death seen in these patients.

Erectile dysfunction, metabolic syndrome, and cardiovascular risks: facts and controversies

Erectile dysfunction (ED) is the most common male sexual dysfunction, and shares many risk factors with systemic conditions including cardiovascular disease (CVD) and the metabolic syndrome (MetS). ED is considered to be an independent risk factor for CVD and can be a harbinger of future cardiovascular events. Given this relationship, each encounter for ED should be viewed by healthcare providers as an opportunity to screen for CVD and other comorbid conditions, including the MetS, that can significantly affect a man's overall health. While universally accepted screening guidelines are lacking, expert panels do recommend an approach to risk stratification in men with ED. In this review, we discuss the current state of understanding of the relationship between ED, the MetS, and CV risk, and how this impacts the approach to the patient presenting with ED.

Sex Differences in the Effect of Atomoxetine on the QT Interval in Adult Patients With Attention-Deficit Hyperactivity Disorder

BACKGROUND

The effects of atomoxetine on QT in adults remain unclear. In this study, we examined whether the use of atomoxetine to treat attention-deficit hyperactivity disorder in adults is associated with QT prolongation.

METHODS

Forty-one subjects with attention-deficit hyperactivity disorder were enrolled in this study. Participants were administered 40, 80, or 120 mg atomoxetine daily and were maintained on their respective dose for at least 2 weeks. We conducted electrocardiographic measurements and blood tests, measuring plasma atomoxetine concentrations after treatment. Electrocardiograms of 24 of the patients were also obtained before atomoxetine treatment. The QT interval was corrected using Bazett (QTcB) and Fridericia (QTcF) correction formulas.

RESULTS

In these 24 patients, only the female patients had prolonged QTcB (P = 0.039) after atomoxetine treatment. There was no correlation between plasma atomoxetine concentrations and the corrected QT interval (QTc), or between atomoxetine dosage and the QTc. However, in female patients, there was a significant positive correlation between atomoxetine dosage and the QTcB (r = 0.631, P = 0.012), and there was a marginally significant positive correlation between atomoxetine dosage and the QTcF (r = 0.504, P = 0.055). In male patients, there was no correlation between atomoxetine dosage and the QTcB or QTcF intervals. There was no correlation between plasma atomoxetine concentrations and the QTc in either female or male patients.

IMPLICATIONS

Clinicians should exhibit caution when prescribing atomoxetine, particularly for female patients.

Influence of steroid hormones on ventricular repolarization

QT interval prolongation, corrected for heart rate (QTc), either spontaneous or drug-induced, is associated with an increased risk of torsades de pointes and sudden death. Women have longer QTc than men and are at higher risk of torsades de pointes, particularly during post-partum and the follicular phase. Men with peripheral hypogonadism have longer QTc than healthy controls. The role of the main sex steroid hormones has been extensively studied with inconsistent findings. Overall, estradiol is considered to promote QTc lengthening while progesterone and testosterone shorten QTc. New findings suggest more complex regulation of QTc by sex steroid hormones involving gonadotropins (i.e. follicle-stimulating hormone), the relative concentrations of sex steroid hormones (which depends on gender, i.e., progesterone/estradiol ratio in women). Aldosterone, another structurally related steroid hormone, can also prolong ventricular repolarization in both sex. Better understanding of pathophysiological hormonal processes which may lead to increased susceptibility of women (and possibly hypogonadic men) to drug-induced arrhythmia may foster preventive treatments (e.g. progesterone in women). Exogenous hormonal intake might offer new therapeutic opportunities or, alternatively, increase the risk of torsades de pointes. Some exogenous sex steroids may also have paradoxical effects on ventricular repolarization. Lastly, variations of QTc in women linked to the menstrual cycle and sex hormone fluctuations are generally ignored in regulatory thorough QT studies. Investigators and regulatory agencies promoting inclusion of women in thorough QT studies should be aware of this source of variability especially when studying drugs over several days of administration.

QT Prolongation and Oncology Drug Development

Many pharmaceutical agents interact with cardiac ion channels resulting in abnormal ventricular repolarization and prolongation of the QT interval. In rare circumstances, this has resulted in the development of the potentially life-threatening arrhythmia, torsades de pointes. It is recognized, however, that accurate measurement of the QT interval is challenging, and it is a poor predictor for the development of this arrhythmia. Nevertheless, QT interval monitoring is an essential part of pharmaceutical development, and significant increases in the QT interval may prevent a drug from gaining approval.

Roles of Testosterone Replacement in Cardiac Ischemia-Reperfusion Injury

Testosterone is an anabolic steroid hormone, which is the major circulating androgen hormone in males. Testosterone levels decreasing below the normal physiological levels lead to a status known as androgen deficiency. Androgen deficiency has been shown to be a major risk factor in the development of several disorders, including obesity, metabolic syndrome, and ischemic heart disease. In the past decades, although several studies from animal models as well as clinical studies demonstrated that testosterone exerted cardioprotection, particularly during ischemia-reperfusion (I/R) injury, other preclinical and clinical studies have shown an inverse relationship between testosterone levels and cardioprotective effects. As a result, the effects of testosterone replacement on the heart remain controversial. In this review, reports regarding the roles of testosterone replacement in the heart following I/R injury are comprehensively summarized and discussed. At present, it may be concluded that chronic testosterone replacement at a physiological dose demonstrated cardioprotective effects, whereas acute testosterone replacement can cause adverse effects in the I/R heart.

Transverse false tendons in the left ventricular cavity are associated with early repolarization

BACKGROUND

Left ventricular false tendons (LVFTs) are related to precordial murmurs, ventricular arrhythmias and some repolarization abnormalities. Early repolarization (ER) is a specific type of repolarization abnormality.

OBJECTIVE

The aim of the present study was to investigate the relationship between LVFTs and ER.

METHODS

This study retrospectively included 99 consecutive healthy subjects and 33 patients with ER. Early repolarization was defined as an elevation of the QRS-ST junction of >0.1 mV from baseline in at least 2 inferior or lateral leads, manifested as QRS slurring or notching. Each participant was examined using echocardiography with second harmonic imaging, and the attachments of the LVFTs were recorded.

RESULTS

A total of 93 LVFTs were present in 82 (83%) of the 99 healthy subjects. Of these 93 LVFTs, the majority (79/93, or 84.9%) were longitudinal-type LVFTs, which originated from the basal interventricular septum (IVS) and progressed toward the apical segment of the left ventricular free wall. There were significant differences in the positioning of the LVFTs between the ER patients and control (P < 0.0001). LVFTs between mid-IVS to the middle of the LV free wall were found more common in patients with ER compared with control subjects (47.5% vs. 6.5%, P < 0.0001). In the ER group, LVFTs between the basal IVS to the apical segment of LV free wall were only identified in 21% of the LVFTs, compared to a value of 84.9% for the control group (P < 0.0001). The distribution of LVFT trends in the ER group was also significantly different from that in the control group (P < 0.05).

CONCLUSIONS

LVFTs are commonly visualized using echocardiography. An LVFT from the basal IVS to the apical segment of the left ventricular free wall may be a normal anatomical structure in the left ventricular cavity. On the contrary, transverse false tendons in the left ventricular cavity may be associated with ER.

QTc prolongation in schizophrenia patients in Asia: clinical correlates and trends between 2004 and 2008/2009

OBJECTIVE

Little is known about the pattern of QT interval (QTc) prolongation in Asian patients with schizophrenia. This study examined trends of QTc prolongation in schizophrenia inpatients in six Asian countries and territories between 2004 and 2008/2009 and its independent demographic and clinical correlates.

METHOD

Data on 3482 hospitalized schizophrenia patients (2004 = 1826 and 2008/2009 = 1656) in six Asian countries and territories were collected by either chart review or interviews during a 1-month period. Patients' sociodemographic and clinical characteristics, prescriptions of psychotropic drugs, and QTc interval were recorded using a standardized protocol and data collection procedure.

RESULTS

The frequency of QTc prolongation (>456 ms) was 2.4% in the whole sample, decreasing from 3.1% in 2004 to 1.6% in 2008/2009 (p = 0.004) with wide intercountry variations. However, this decreased trend was driven by decreased QTc prolongation detected in China and Hong Kong (both p-values < 0.05). Multiple logistic regression analysis of the whole sample revealed that patients having more likely to have an illness lasting longer than 5 years and received antipsychotics classified as list-1 drugs according to the Arizona Centre for Education and Research on Therapeutics. Compared with 2004, patients in 2008/2009 were less likely to have QTc prolongation. Thioridazine caused QTc prolongation most frequently (odds ratio (OR) 4.4; 95% confidence interval (CI) 1.2-15.2), followed by sulpiride (OR 2.4; 95% CI 1.3-4.5), clozapine (OR 2.4; 95% CI 1.4-4.2), and chlorpromazine (OR 1.9; 95% CI 1.07-3.5).

CONCLUSIONS

Frequency of QTc prolongation was low in Asian patients with schizophrenia. QTc prolongation in schizophrenia decreased in China and Hong Kong between 2004 and 2008/2009 but increased in Taiwan over the same period, remaining low in the other countries.

Etiology of cardiovascular disease in patients with schizophrenia: current perspectives

Cardiovascular morbidity and mortality are important problems among patients with schizophrenia. A wide spectrum of reasons, ranging from genes to the environment, are held responsible for causing the cardiovascular risk factors that may lead to shortening the life expectancy of patients with schizophrenia. Here, we have summarized the etiologic issues related with the cardiovascular risk factors in schizophrenia. First, we focused on heritable factors associated with cardiovascular disease and schizophrenia by mentioning studies about genetics-epigenetics, in the first-episode or drug-naïve patients. In this context, the association and candidate gene studies about metabolic disturbances in schizophrenia are reviewed, and the lack of the effects of epigenetic/posttranscriptional factors such as microRNAs is mentioned. Increased rates of type 2 diabetes mellitus and disrupted metabolic parameters in schizophrenia are forcing clinicians to struggle with metabolic syndrome parameters and related issues, which are also the underlying causes for the risk of having cardiometabolic and cardiovascular etiology. Second, we summarized the findings of metabolic syndrome-related entities and discussed the influence of the illness itself, antipsychotic drug treatment, and the possible disadvantageous lifestyle on the occurrence of metabolic syndrome (MetS) or diabetes mellitus. Third, we emphasized on the risk factors of sudden cardiac death in patients with schizophrenia. We reviewed the findings on the arrhythmias such as QT prolongation, which is a risk factor for Torsade de Pointes and sudden cardiac death or P-wave prolongation that is a risk factor for atrial fibrillation. For example, the use of antipsychotics is an important reason for the prolongation of QT and some other cardiac autonomic dysfunctions. Additionally, we discussed relatively rare issues such as myocarditis and cardiomyopathy, which are important for prognosis in schizophrenia that may have originated from the use of antipsychotic medication. In conclusion, we considered that the studies and awareness about physical needs of patients with schizophrenia are increasing. It seems logical to increase cooperation and shared care between the different health care professionals to screen and treat cardiovascular disease (CVD)-risk factors, MetS, and diabetes in patients with psychiatric disorders, because some risk factors of MetS or CVD are avoidable or at least modifiable to decrease high mortality in schizophrenia. We suggested that future research should focus on conducting an integrated system of studies based on a holistic biopsychosocial evaluation.

QT Interval in Pregnant and Non-pregnant Women

INTRODUCTION

Prolongation of QT interval might result in dangerous cardiac arrhythmias, including Torsades de Pointes (TdP), consequently leading to syncope or death. A limited number of studies carried out in this respect to date have shown that QT interval might increase during pregnancy. On the other hand, it has been shown that each pregnancy might result in an increase in the risk of cardiac accidents in patients with long QT interval. Therefore, the present study was undertaken to compare QT intervals in pregnant and non-pregnant women.

METHODS

Pregnant women group consisted of 40 women in the second and third trimesters of pregnancy and the non-pregnant control group consisted of healthy women 18-35 years of age. All the patients underwent standard 12-lead electrocardiogram (ECG). The QT interval was measured for each patient at lead II. The mean corrected QT interval (QTc) and QT dispersions (QTd) were compared between the two groups.

RESULTS

Mean heart rates in the pregnant and non-pregnant groups were 98.55±14.09 and 72.53±13.17 beats/minutes (P<0.001). QTd and QTc means were in the normal range in both groups; however, these variables were 49.50±12.80 and 43.03±18.47 milliseconds in the pregnant group and 39.5±9.59 and 40.38±17.20 milliseconds in the control group, respectively (P<0.001).

CONCLUSION

The QT interval was longer in pregnant women compared to non-pregnant women; however, it was in the normal range in both groups. Therefore, it is important to monitor and manage risk factors involved in prolongation of QT interval and prevent concurrence of these factors with pregnancy.

Oral contraceptive use and the ECG: evidence of an adverse QT effect on corrected QT interval

BACKGROUND

A prolonged corrected QT (QTc) interval is a marker for an increased risk of sudden cardiac death. We evaluated the relationship between oral contraceptive (OC) use, type of OC, and QTc interval.

METHODS

We identified 410,782 ECGs performed at Northern California Kaiser Permanente on female patients between 15 and 53 years from January, 1995 to June, 2008. QT was corrected for heart rate using log-linear regression. OC generation (first, second and third) was classified by increasing progestin androgenic potency, while the fourth generation was classified as antiandrogenic.

RESULTS

Among 410,782 women, 8.4% were on OC. In multivariate analysis after correction for comorbidities, there was an independent shortening effect of OCs overall (slope = -0.5 ms; SE = 0.12, P < 0.0002). Users of first and second generation progestins had a significantly shorter QTc than nonusers (P < 0.0001), while users of fourth generation had a significantly longer QTc than nonusers (slope = 3.6 ms, SE = 0.35, P < 0.0001).

CONCLUSION

Overall, OC use has a shortening effect on the QTc. Shorter QTc is seen with first and second generation OC while fourth generation OC use has a lengthening effect on the QTc. Careful examination of adverse event rates in fourth generation OC users is needed.

Sex differences in the effect of four second-generation antipsychotics on QTc interval in patients with schizophrenia

OBJECTIVE

We examined sex differences in the effect of olanzapine (OLZ), risperidone (RIS), aripiprazole (ARP), or quetiapine (QTP) on mean corrected QT (QTc) intervals among 222 patients with schizophrenia.

METHODS

Subjects were patients with schizophrenia who were treated with either OLZ (n = 69), RIS (n = 60), ARP (n = 62), or QTP (n = 31). Electrocardiographic measurements were conducted, and the QT interval was corrected using Bazett's correction formula.

RESULTS

The mean QTc interval of the QTP group was significantly longer than that of the RIS group (p = 0.002) or ARP group (p = 0.029). The mean QTc interval of the OLZ group was also significantly longer than that of the RIS group (p = 0.006). In female participants, the difference in the mean QTc interval among the four second-generation antipsychotic (SGA) groups was statistically significant (p = 0.002), whereas in male patients, there was no significant difference in the mean QTc interval among the four SGA groups. Post hoc analyses showed that sex differences in QTc interval were observed only in OLZ treatment group (p = 0.007).

CONCLUSION

To our knowledge, this is the first study to demonstrate sex differences in the effect of four SGAs on the QTc interval.

The Generation R Study: design and cohort update 2012

The Generation R Study is a population-based prospective cohort study from fetal life until adulthood. The study is designed to identify early environmental and genetic causes and causal pathways leading to normal and abnormal growth, development and health during fetal life, childhood and adulthood. The study focuses on six areas of research: (1) maternal health; (2) growth and physical development; (3) behavioural and cognitive development; (4) respiratory health and allergies; (5) diseases in childhood; and (6) health and healthcare for children and their parents. Main exposures of interest include environmental, endocrine, genetic and epigenetic, lifestyle related, nutritional and socio-demographic determinants. In total, n = 9,778 mothers with a delivery date from April 2002 until January 2006 were enrolled in the study. Response at baseline was 61 %, and general follow-up rates until the age of 6 years exceed 80 %. Data collection in mothers, fathers and children include questionnaires, detailed physical and ultrasound examinations, behavioural observations, and biological samples. A genome and epigenome wide association screen is available in the participating children. From the age of 5 years, regular detailed hands-on assessments are performed in a dedicated research center including advanced imaging facilities such as Magnetic Resonance Imaging. Eventually, results forthcoming from the Generation R Study contribute to the development of strategies for optimizing health and healthcare for pregnant women and children.

Sex hormones and the QT interval: a review

A prolonged QT interval is a marker for an increased risk of ventricular tachyarrhythmias. Both endogenous and exogenous sex hormones have been shown to affect the QT interval. Endogenous testosterone and progesterone shorten the action potential, and estrogen lengthens the QT interval. During a single menstrual cycle, progesterone levels, but not estrogen levels, have the dominant effect on ventricular repolarization in women. Studies of menopausal hormone therapy (MHT) in the form of estrogen-alone therapy (ET) and estrogen plus progesterone therapy (EPT) have suggested a counterbalancing effect of exogenous estrogen and progesterone on the QT. Specifically, ET lengthens the QT, whereas EPT has no effect. To date, there are no studies on oral contraception (OC) and the QT interval, and future research is needed. This review outlines the current literature on sex hormones and QT interval, including the endogenous effects of estrogen, progesterone, and testosterone and the exogenous effects of estrogen and progesterone therapy in the forms of MHT and hormone contraception. Further, we review the potential mechanisms and pathophysiology of sex hormones on the QT interval.

High prevalence of prolonged QT interval in obese hypogonadal males

Obese subjects show several electrocardiographic alterations, including prolonged QT interval, a marker for fatal cardiac arrhythmias. Prolonged QT interval has recently been linked to low testosterone levels, a frequent occurrence in male obese patients but no study has yet assessed whether hypoandrogenism contributes to QT interval prolongation in this population. Aim of this study was to evaluate whether prolonged QT interval is linked to hypogonadism in male obese subjects. QT interval corrected for heart rate (QTc) was measured from standard electrocardiogram recordings in 136 obese men (BMI 30 >kg/m(2), range 30.1-75.4 kg/m(2)). Obese men were classified as eugonadal or hypogonadal according to serum total testosterone levels (i.e., greater or less than 9.9 nmol/l). Our study showed that QTc measurements corrected by either Bazett (419 ± 3.2 vs. 408 ± 3.4 ms, P < 0.05), Fridericia (406.3 ± 3.39 vs. 396.4 ± 3.03 ms, P < 0.05) or Hodges (407.0 ± 3.12 vs. 397.3 ± 2.84 ms, P < 0.05) were longer in hypogonadal compared with eugonadal obese men; further, prolonged QTc interval (i.e., >440 ms) was more frequent among hypogonadal compared with eugonadal obese men (23% vs. 10%, P < 0.05). The degree of weight excess, diabetes, sleep apnoea and potassium levels were not associated with prolonged QTc. In conclusion, obese hypogonadal men show a greater prevalence of prolonged QT interval compared with their eugonadal counterparts. It appears therefore that low levels of testosterone in obese men may contribute to the arrhythmogenic profile of these patients, a heretofore unknown link which warrants further clinical attention.

Sex-steroid hormones and electrocardiographic QT-interval duration: findings from the third National Health and Nutrition Examination Survey and the Multi-Ethnic Study of Atherosclerosis

The association between physiologic levels of sex hormones and QT-interval duration in humans was evaluated using data from 727 men enrolled in the Third National Health and Nutrition Examination Survey and 2,942 men and 1,885 postmenopausal women enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA). Testosterone, estradiol, and sex hormone-binding globulin levels were measured in serum and free testosterone was calculated from those values. QT interval was measured using a standard 12-lead electrocardiogram. In men from the Third National Health and Nutrition Survey, the multivariate adjusted differences in average QT-interval duration comparing the highest quartiles with the lowest quartiles of total testosterone and free testosterone were -8.5 ms (95% confidence interval (CI): -15.5, -1.4) and -8.0 ms (95% CI: -13.2, -2.8), respectively. The corresponding differences were -1.8 ms (95% CI: -3.8, -0.2), and -4.7 ms (95% CI: -6.7, -2.6), respectively, in men from MESA and -0.6 ms (95% CI: -3.0, 1.8) and 0.8 ms (95% CI: -1.6, 3.3), respectively, in postmenopausal women from MESA. Estradiol levels were not associated with QT-interval duration in men, but there was a marginally significant positive association in postmenopausal women. The findings suggest that testosterone levels may explain differences in QT-interval duration between men and women and could be a contributor to population variability in QT-interval duration among men.

Invited commentary: sex-steroid hormones and QT-interval duration

In this issue of the Journal, Zhang et al. (Am J Epidemiol. 2011;174(4):403-411) make a substantial contribution to research in the area of hormonal influences on cardiac repolarization by demonstrating an inverse association between testosterone levels and the Bazett's adjusted QT interval (QTc) and RR-adjusted QT interval in men but not in postmenopausal women. They suggest that testosterone levels might explain the difference in QTc-interval duration between men and women and could contribute to population variability in QTc-interval duration among men. In this commentary, the gender difference and the role of testosterone in human cardiac repolarization are addressed. In addition, the gender differences in the congenital long-QT syndrome, drug-induced ventricular arrhythmias, and sudden cardiac death are discussed.

The Rotterdam Study: 2012 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, oncological, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over a 1,000 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

Sex difference in QTc prolongation in chronic institutionalized patients with schizophrenia on long-term treatment with typical and atypical antipsychotics

OBJECTIVE

The rate-corrected electrocardiographic QT (QTc) interval may significantly increase in patients with schizophrenia taking antipsychotics. The objective of this naturalistic study was to assess the prevalence of prolonged QTc interval in a large population of inpatients with chronic schizophrenia and to explore QTc relationship with demographic variables and prescribed treatments.

MATERIALS AND METHODS

Electrocardiograms were obtained from age- and sex-matched 456 controls and 1,006 inpatients with schizophrenia (male/female = 689/317) taking antipsychotics. QTc prolongation was defined as a mean value of two standard deviations above the controls. The adjusted relative risk was calculated using logistic regression analysis.

RESULTS

QTc prolongation was present in 45 (4.5%) of 1,006 patients overall. Fewer men (3.2%, 22 of 689) than women (7.3%, 23 of 317) displayed QTc prolongation (p < 0.004). Moreover, QTc intervals were shorter in male (391 ± 31 ms) than female subjects (400 ± 37 ms) (p < 0.001). Clozapine was found to produce a longer QTc intervals compared to risperidone and typical antipsychotics. Furthermore, multiple regression analysis showed that significant predictors for QTc prolongation were comorbid cardiovascular disease, antipsychotic types, sex, and age (all p < 0.01).

CONCLUSION

Our present findings suggest that there are sex differences in the prevalence of QTc prolongation and QTc lengthening in schizophrenia. Antipsychotic types are risk factors for QTc prolongation, and risks are substantially higher for clozapine.

Male hormonal contraception: potential risks and benefits

An effective, safe, reversible, and acceptable method of contraception is an important component of reproductive health and provides the opportunity of shared responsibility for family planning for both partners. Female hormonal contraceptives have been proven to be safe, reversible, available and widely acceptable by different populations. In contrast, male hormonal contraception, despite significant progress showing contraceptive efficacy comparable to female hormonal methods during last three decades, has not yet led to an approved product. Safety of a pharmaceutical product is an appropriate concern but the majority of male hormonal contraceptive clinical trials have not reported significant short term safety concerns. While the absence of serious adverse effects is encouraging, the studies have been designed for efficacy endpoints not long term safety. In this review we summarize potential risks and benefits of putative male hormonal contraceptives on reproductive and non-reproductive organs. While the review covers what we believe will be the likely class of drugs used for male hormonal contraception a true assessment of long term risks and benefits cannot be achieved without an available product.

Effects of testosterone on the Q-T interval in older men and older women with chronic heart failure

The Q-Tc interval duration on the electrocardiogram is recognized to differ between the sexes. In vitro data and data from humans before and after puberty and menopause suggest that sex hormones play a role in the longer Q-Tc intervals in women, or conversely, the shorter Q-Tc intervals in men. Direct investigations of sex hormone effects on the Q-Tc interval in humans, however, are limited and reach conflicting conclusions. Our objective was to determine effects of testosterone on ECG Q-T intervals of older men and older women. ECG's from 84 older men and older women in double-blind placebo-controlled investigations of testosterone supplementation for the treatment of chronic heart failure (CHF) were analysed. Thirty men received 1000mg intramuscular long-acting testosterone undecanoate and 28 men received saline at 0, 6 and 12weeks. ECG's were recorded at baseline and 12weeks. Sixteen women received transdermal testosterone (33μg) and 10 women received matching placebo twice weekly for 24 weeks with ECG's at baseline and after 24weeks. Testosterone, but not placebo, shortened Q-T and Q-Tc intervals without heart rate changes. Q-T intervals decreased from 385±28 (mean±SD) to 382±28 ms (p<0.002) and Q-Tc intervals decreased from 398±26 to 392±27 (p<0.006) in men on testosterone. In women, Q-T intervals decreased from 400±25 to 397±23ms (p=0.06) and Q-Tc intervals from 415±26 to 409±27ms (p=0.3) on testosterone. Q-T intervals were longer in women compared with men under all conditions (p<0.03). The data support a direct effect of testosterone to shorten Q-T intervals in older men and older women in the absence of HR changes or hypogonadal status. Mean decreases are small and unlikely to affect risks of arrhythmic events in patients receiving Q-T prolonging medications.