Prevalence Of Prolonged QTc Interval Research Articles

Acquired prolonged QT interval in patients with Type 2 diabetes: Prevalence a risk factor

The QT interval on the electrocardiogram (ECG) represents the total duration of depolarization and repolarization of the ventricles, its lengthening is associated with rhythm disturbances and increased mortality. QT interval prolongation occurs in approximately 26% of type 2 diabetics. The objective of this study was to assess the prevalence and risk factors of QTc prolongation in patients with type 2 diabetes in a 3-day cross-sectional study conducted at the Department of Endocrinology and Diabetology, Mohammed VI University Hospital, Marrakech, including volunteer type 2 diabetes patients admitted out of emergency. The QT interval was measured manually on ECG tracings. QTc was calculated using Bazett's formula, a QTc interval at the ECG > 440 ms for men and women was considered pathological. Demographic and biological data were also collected. Potential risk factors for prolonged QTc interval were evaluated. Results: We included 126 patients. The mean age of the patients was 57.59 years. The mean duration of diabetes progression was 8.26 years. Mean glycated hemoglobin (HbA1c) was 8.04%, 5.55% were smokers, 2.38% were on diuretics and mean QTc was 432.65 ms. The prevalence of prolonged QTc interval in our patients was 27.77% (21.42% of women and 6.35% of men (p=0.645). Smoking (p=0.025), diuretics (p=0.046) and duration of diabetes (p=0.02) were the significant risk factors in our study.

PO49 Presentation Time: 10:00 AM: Prevalence of QTc Prolongation in Prostate Cancer Patients Undergoing Brachytherapy

<h3>Purpose</h3> QTc has been associated not only with a higher risk of Torsade de Pointes (TdP), sudden cardiac arrest but also with general cardiac mortality, including cardiovascular and coronary death. We examined the prevalence of prolonged QTc interval in prostate cancer patients undergoing brachytherapy in general and in patients with more aggressive cancers who may be exposed to ADT and compared them to patients who underwent prostatectomy. <h3>Materials and Methods</h3> We randomly selected 1094 patients treated with either low-dose rate (LDR) or high-dose rate (HDR) brachytherapy between August 2010 and February 2022 from our internal database. All patients had an ECG as part of the preoperative work-up. The QTc was automatically calculated using the Bazett formula. Excluded were patients with left or complete bundle branch block, ventricular extrasystoles, atrial fibrillation, presence of a pacemaker or a QRS ≥ 120 ms. .As primary outcome, a QTc ≥450ms was considered abnormal. Chi-square or Fisher's exact test, when appropriate was used to compare groups. Pearson correlation coefficient and binary multivariable regression analysis was used to evaluate correlations between QTc and clinical values. <h3>Results</h3> A total of 6.2% (n=68) had a QTc ≥450ms. Patients with a Cancer of the Prostate Risk Assessment (CAPRA) high risk disease (score 6-10) were significantly more likely to have a QTc ≥450ms than patients with low-or intermediate risk (9.7% vs. 5.5%, p=0.039). QTc as a continuous variable correlated weakly with the neutrophil count (r=0.13, p<0.001), age (r=0.08, p=0.009) and inversely with testosterone (r=-0.17, p=0.002). On binary multivariable regression analysis including neutrophils, testosterone and age, only testosterone [nmol/L] was predictive of a QTc ≥450ms, OR 0.9, 95% CI 0.82-0.98, p=0.02. We then compared the patients treated with brachytherapy to 178 patients who underwent prostatectomy. The latter had a non-significantly smaller portion of patient with a QTc ≥450ms: 4.5% vs. 6.2%, p=0.5. <h3>Conclusions</h3> Our data show that about 10% of patients with high-risk prostate cancer are at increased risk of TdP. Treating physicians should be aware of this and monitor the QTc during ADT to possible decrease cardiac mortality in these patients who require ADT. The correlation between increasing age, neutrophil count and low testosterone with QTc prolongation links inflammation and hypogonadism.

The relationship between adenosine deaminase and heart rate-corrected QT interval in type 2 diabetic patients.

BackgroundProlonged heart rate-corrected QT (QTc) interval may reflect poor prognosis of patients with type 2 diabetes (T2D). Serum adenosine deaminase (ADA) levels are related to hyperglycemia, insulin resistance (IR) and inflammation, which may participate in diabetic complications. We investigated the association of serum ADA levels with prolonged QTc interval in a large-scale sample of patients with T2D.MethodsIn this cross-sectional study, a total of 492 patients with T2D were recruited. Serum ADA levels were determined by venous blood during fasting. QTc interval was estimated from resting 12-lead ECGs, and prolonged QTc interval was defined as QTc > 440 ms.ResultsIn this study, the prevalence of prolonged QTc interval was 22.8%. Serum ADA levels were positively associated with QTc interval (r = 0.324, P < 0.0001). The proportion of participants with prolonged QTc interval increased significantly from 9.2% in the first tertile (T1) to 24.7% in the second tertile (T2) and 39.0% in the third tertile (T3) of ADA (P for trend < 0.001). After adjusting for other possible risk factors by multiple linear regression analysis, serum ADA level was still significantly associated with QTc interval (β = 0.217, t = 3.400, P < 0.01). Multivariate logistic regression analysis showed that female (OR 5.084, CI 2.379–10.864, P < 0.001), insulin-sensitizers treatment (OR 4.229, CI 1.290–13.860, P = 0.017) and ADA (OR 1.212, CI 1.094–1.343, P < 0.001) were independent contributors to prolonged QTc interval.ConclusionsSerum ADA levels were independently associated with prolonged QTc interval in patients with T2D.

Association between Triglyceride Glucose Index and Corrected QT Prolongation in Chinese Male Steelworkers.

Objectives: Increased triglyceride glucose (TyG) index appears to be linked to carotid and coronary atherosclerosis and calcifications and possesses an elevated future risk of developing cardiovascular disease. Corrected QT (QTc) interval prolongation is associated with ventricular arrhythmias and sudden cardiac death, and a high prevalence of prolonged QTc interval was previously reported in blue-collar workers. The purpose of this study was to find the possible causal inter-relationship between TyG index and QTc interval in a large population of Chinese male steelworkers. Methods: A total of 3189 male workers from two steel plants were enrolled. They responded to a cross-sectional questionnaire on basic attributes and lifestyle, including sleep patterns. All workers in the two plants underwent periodic health checkups, including twelve-lead electrocardiography. Structural equation modeling (SEM) was used to assess the direct and indirect effects of TyG index on QTc interval. Results: With increasing TyG index tertile, the male steelworkers had an increased QTc interval. Applying multivariate analysis, TyG index was associated independently with the odds of QTc prolongation (adjusted odds ratio = 2.73, 95% confidence interval = 1.39–5.24, p = 0.004). SEM revealed that TyG index, hypertension, obesity, lifestyle, white blood cell (WBC) count, and liver function had statistically significant direct effects on QTc interval. Furthermore, TyG index also had an indirect effect on QTc interval through hypertension, obesity, WBC count, and liver function. Moreover, lifestyle had an indirect effect on QTc interval through TyG index. The final model explained 14% of the variability in QTc interval. Conclusions: An increased TyG index was associated with QTc interval prolongation in this study, and SEM delineated possible causal pathways and inter-relationships of the risk factors contributing to the occurrence of QTc prolongation among Chinese male steelworkers.

High prevalence of prolonged QTc interval among individuals in ambulatory diabetic care in southwestern Uganda.

Heart rate-corrected QT (QTc) interval is associated with increased risk for cardiovascular events and mortality among individuals with diabetes mellitus (DM). Little is known about the epidemiology of prolonged QTc among people with DM in resource-limited settings. We conducted a cross-sectional study among adults with diabetes in ambulatory care at the Mbarara Regional Referral Hospital, from November 2018 to April 2019. Twelve-lead ECG recordings were performed on all participants. We collected clinical and laboratory data related to diabetes disease status and treatment control. We estimated QTc using Bazett's formula and categorized it according to standardized sex-adjusted thresholds. Linear regression analysis was performed to identify correlates of QTc. We recruited 299 participants with a mean age of 50.1 years (SD±9.8) and mean HbA1c of 9.7 % (SD±2.6), and 69.6% were female. We detected prolonged and borderline QTc in 6.4% (19/299, 95% CI: 3.9-9.7%) and 23.4% (70/299, 95% CI: 18.7-28.6%) of participants, respectively. In multivariate models, factors associated with increasing QTc interval were mean arterial pressure (β=0.34; 95% CI: 0.07-0.63, p=0.019) and female sex (β=15.26; 95% CI: 7.58-22.94, p0.001). The prevalence of abnormal QTc among individuals in routine diabetes care in southwestern Uganda was high. Female sex and mean arterial pressure were correlated with QTc interval. Given these findings, future studies should explore the clinical impact of abnormal QTc in this patient population.

Title: Risk factors of prolonged corrected QT interval among patients with mental disorders

IntroductionThere is an increased rate of sudden cardiac death in mental health patients. Studies provide consistent evidence that prolonged QT interval is associated with higher risk of all-cause and cardiovascular mortality.ObjectivesThis study aimed to assess the prevalence of prolonged QTc interval (corrected QT&gt;450 milliseconds) and to determine the possible factors in hospitalized psychiatric patients.MethodsWe reviewed records of all mental health inpatient admissions to the psychiatry “C” department at Hedi Chaker university hospital in Sfax, between 1 february and 30 april 2019. Electrocardiogram (ECG) availability was noted and QTc interval was manually measured. Sociodemographic, clinical, biological and therapeutic data were collected.ResultsOf 68 mental health inpatient admissions, 59 (86.6 %) presentations had an ECG. A total of seven (11.8 %) had a prolonged QTc interval. These seven patients were treated with typical antipsychotics. Of the 7 patients with a prolonged QTc, 4 patients (57.1%) suffered from schizophrenia. QTc prolongation was significantly correlated with the presence of a recent physical trauma (p = 0.021), dietary restriction (p = 0.026), and taking at least two antipsychotics (p = 0.008). Moreover, this prolongation of QTc was linked to a longer duration of disease and an older age, without significant associations.ConclusionsOur study supports an association between a prolonged QTc interval and clinical situations at risk and antipsychotic polypharmacy. However, a larger study with routine ECG screening is required to better assess the significance of this problem.

Prevalence of Prolonged QTc Interval in Patients Discharged Home Directly from the Emergency Department

Prevalence of Prolonged QTc Interval in Patients Discharged Home Directly from the Emergency Department

Prevalence and risk factors of prolonged corrected QT interval in general Chinese population

BackgroundCorrected QT (QTc) interval has been correlated with total and CVD mortality. Although much is known about the relation between prolonged QTc interval and clinical outcome, there is no information on the prevalence and specific risk factors of QTc prolongation in general Chinese population. We evaluated the prevalence of prolonged QTc interval and its risk factors in general Chinese population, aiming to fill in the gaps in the literature and provide evidence for potential CVD risk prediction and disease burden estimate in community.MethodsA population-based survey was conducted on 11,209 participants over the age of 35 in rural areas of Liaoning Province from 2012 to 2013. Twelve-lead ECGs and automatic analysis were performed on all participants. Logistic regression adjustments were made by using the Bazett’s formula to correlate specific risk factors with prolonged QTc intervals (> 440 ms) for potential confounders.ResultsThe overall prevalence of prolonged QTc interval was 31.6%. The prevalence increased significantly with age (24.1% among those aged 35–44 years; 28.3%, 45–54 years; 35.2%, 55–64 years; 43.4%, ≥65 years, P < 0.001). Participants with a history of CVD had a higher prevalence of QTc prolongation (40.7% vs. 30.0%). In the fully adjusted logistic regress model, older age, abdominal obesity, hypertension, diabetes, hypokalemia and any medicine used in the past two weeks were associated independently with increased risk for prolonged QTc interval (All P < 0.05). We found no significant differences between general obesity, hypocalcemia and hypomagnesemia with prolongation of QTc interval. Female sex showed opposite results after applying clinical diagnostic criteria, and high physical activity could reduce the risk of prolonged QTc interval.ConclusionsThe prevalence of prolonged QTc interval was relatively high in general Chinese population and listed relevant factors, which would help identify patients at risk in pre-clinical prevention and provide evidence for estimating potential CVD burden and making management strategies in community.

Independent Influence of Blood Pressure on QTc Interval: Results from a General Chinese Population.

Aims We performed the current study primarily to characterize the independent association of blood pressure with heart rate-corrected QT (QTc) interval after adjusting for cardiovascular confounding factors and left ventricular mass (LVM) in a large general population in China. Methods All enrolled 10,553 permanent residents with age ≥ 35 years from Liaoning Province were investigated by a questionnaire and then subjected to physical examinations, laboratory analyses, and electrocardiogram (ECG) as well as echocardiogram at the same visit. Multivariate linear and logistic regression analyses were conducted to assess the independent association of blood pressure with QTc interval. Results Hypertensive subjects had significantly longer QTc interval and higher prevalence of prolonged QTc interval compared with normotensive ones in all subgroups stratified by gender and left ventricular hypertrophy (LVH) (all Ps ≤ 0.001). Multiple relevant clinical confounding factors and LVM were all adjusted in the multivariate linear and logistic regression analyses. As a result, both systolic blood pressure (SBP) and diastolic blood pressure (DBP) were independently associated with QTc interval (β = 0.12 and 0.16, respectively; Ps < 0.001). Furthermore, as categorical variables, hypertension was independently associated with prolonged QTc interval (OR = 1.71; P < 0.001). Sex-specific analyses revealed that the independent associations were detected in both males and females (all Ps < 0.001). Conclusions These key findings of the current study highlighted the fact that hypertension was significantly associated with prolonged QTc interval and the correlations were independent of confounding factors and LVM.

Prevalence of Prolonged QTC Interval in Patients Taking Psychopharmacs

Abstract Apart from providing knowledge on the beneficial effects of drugs, practical psychopharmacotherapy also includes drug profiles of adverse effects, especially when medical comorbidity is present. The mechanism of action of many psychotropic drugs, mainly antipsychotics and antidepressants, is associated with prolongation of the QT interval and the occurrence of arrhythmias, specifically Torsade de pointes (TdP), which can be lethal. The aim of this pilot study was to confirm the prevalence of prolonged QTc interval in a sample of psychiatric patients taking psychopharmacs. The present study included 41 patients who were already on psychopharmacs. The average value of the QTc interval in the observed sample was 413.8±23.3 ms. The most frequent psychopharmacotherapy was the combination of typical and atypical antipsychotics (24.4%), followed by monotherapy with antipsychotics (22%) and combined antidepressant and atypical antipsychotic therapy (22%). The average value of the QTc interval for male patients was 412.1±25.2 ms, whereas for female patients, it was 416.6±20.4 ms. No difference between sexes was confirmed (p=0.555). The correlation between the QTc interval and age of patients was positive but not statistically significant (p=0.072). The highest average (419.3±31.6 ms) and highest maximum (479 ms) values of the QTc interval were noted for patients undergoing combined therapy of antidepressants and atypical antipsychotics. Prolonged values of the QTc interval were observed for seven males and one female, and no patients exhibited pathological values. This study confirmed previous research that found that prolongation of the QTc interval exists in patients in sample groups who take psychopharm acs, but not up to critical values.

Prevalence and prognostic significance of prolonged QTc interval in emergency medical patients: A prospective observational study.

Introduction:QTc interval is affected by many factors and prolongation of same may have prognostic significance. A significant number of patients admitted in medical emergency are acutely ill, have multiple comorbidities and are on medications, all of these factors might affect QTc interval and prognosis.Materials and Methods:Single-center, prospective, observational study was carried out on 279 patients of different illnesses recruited from emergency medical services attached to the Department of Internal Medicine at Postgraduate Institute of Medical Education and Research, Chandigarh, India, a tertiary care hospital.Results:Out of 279 patients, 95 were found to have prolonged QTc interval with the prevalence of 34.1%. Fifteen patients (5.4%) had markedly prolonged QTc interval (QTc >500 ms). Of various medical conditions, we found statistically significantly higher number of patients of chronic kidney disease (P = 0.047), chronic liver disease (P < 0.001), hemorrhagic cerebrovascular accident (P = 0.026), and heart failure (P = 0.009) with prolonged QTc interval. Among laboratory abnormalities, patients with low hemoglobin (P = 0.032), with deranged renal functions (P = 0.033), and with hypokalemia (P = 0.026) had a greater share of patients with prolonged QTc interval. There was no difference in duration of hospital stay and frequency of hospital mortality between two groups, although, on subgroup analysis, patients with markedly prolonged QTc interval had significantly higher hospital mortality (P = 0.029). The frequency of ventricular tachycardia was also significantly higher in patients with prolonged QTc interval (P = 0.008).Conclusion:High prevalence of prolonged QTc interval was found in Indian emergency medical patients. There was no difference in hospital mortality though on subgroup analysis, patients with markedly prolonged QTc interval had significantly more episodes of in-hospital ventricular tachycardia and hospital mortality.

Prolonged repolarization in atrial septal defect: An example of mechanoelectrical feedback due to right ventricular volume overload

Prolonged corrected QT (QTc) intervals are frequently observed in children before atrial septal defect (ASD) closure in our department. The aim of the study was to assess the effect of long-term right ventricular volume overload on repolarization. QRS, QT, and JT intervals were measured manually in leads II and V5 of a standard 12-lead electrocardiogram in 45 children with an isolated ASD a day before and at least 6 months after ASD closure. QT intervals were corrected for heart rate using the Bazett, Fridericia, Framingham, and Hodges formulas. Each QTc interval calculated using the Bazett formula was compared to sex- and age-matched normal values. Individual QTc intervals shortened significantly (P < .001) using all correction formulas, whereas the QRS duration did not change. The prevalence of prolonged QTc interval decreased from 22.2% to 2.2% after shunt closure (P = .007). The QTc interval shortens significantly after the closure of a hemodynamically relevant ASD in childhood. This phenomenon is independent of the used QT correction formula and may reflect a mechanoelectrical feedback associated with right ventricular volume overload.

Body Weight Reduction and QTc Interval in Obesity

Introduction: Obesity is associated with wide variety of electrocardiographic (ECG) abnormalities. Prolonged QTc interval is common in obesity and it represents a delayed ventricular repolarisation which is associated with ventricular arrhythmias, syncope and sudden cardiac death. The aim of our study is to evaluate the effects of weight reduction on QTc interval in obese subjects. Materials and Methods: The study included 74 obese subjects aged 41.78 ± 10.70 years, treated with a lowcalorie diet (800 kcal/day) for two weeks. All patients underwent a standard resting 12-lead surface ECG before and after the treatment. QTc intervals were corrected by Bazett’s formula. Results: The average loss in body weight was 10.26 ± 3.63%, and the average reduction in body mass index was 9.39 ± 4.23%. There were statistically significant differences for all electrocardiographic parameters (p 0.05) before and after the treatment with low-calorie diet. Heart rate was also statistically significant reduced after the low-calorie diet treatment. Prevalence of prolonged QTc interval was 24.32% before and 9.21% after the treatment. Conclusion: The results show that obesity causes prolongation of QTc interval. Significant weight reduction of about 10% leads to favorable electrocardiographic changes and significant shortening of the QTc interval.

Risk of QTc Prolongation in a Cohort of Opioid-Dependent HIV-Infected Patients on Methadone Maintenance Therapy

Concern regarding the QTc interval in human immunodeficiency virus (HIV)-infected patients has been growing in recent years, and cases of prolonged QTc interval and torsades de pointes have been described in HIV-infected patients on methadone therapy. This study aimed to determine the prevalence and factors associated with long QTc interval in a cohort of opioid-dependent HIV-infected patients on methadone maintenance therapy. A cross-sectional study was conducted in opioid-dependent HIV-infected patients on methadone maintenance therapy at a drug abuse outpatient center. Patients with any cardiac disease, drug-positive urine test, electrolyte abnormalities, and changes in their antiretroviral therapy (ART) or methadone doses in the last 2 months were excluded. Heart rate and QT interval in lead II were measured using the Bazett formula. Ninety-one patients were included: 58 (63.7%) were men with a median age of 44.5 years and 68 of 91 (74.7%) were on ART. Median methadone dose was 70 mg/day (range 15-250 mg/day) and mean QTc interval was 438 ± 34 ms. Prolonged QTc interval (>450 ms) was documented in 33 of 91(36.3%) patients, and 3 of 91 (3.2%) had QTc >500 ms. On multiple linear regression analysis, methadone doses (P = .005), chronic hepatitis C-induced cirrhosis (P = .008), and being ART-naive (P = .036) were predictive of prolonged QTc. The prevalence of prolonged QTc interval in opioid-dependent HIV-infected patients on methadone maintenance therapy is high. Risk factors for prolongation of the QTc interval are chronic hepatitis C-induced cirrhosis, higher methadone doses, and being ART-naive. Thus, electrocardiographic monitoring is required to minimize cardiovascular morbidity and mortality in this specific HIV group.

Prevalence of prolonged QTcinterval in electrocardiograms of 1 -12 year-old seizure patients

Background: Children with long QT intervals are prone to life-threatening ventricular arrhythmias which may lead to seizure and syncope and may be misdiagnosed as seizure. Objective: This study aimed to assess the frequency of long QT intervals in children with and without convulsion. Method: This study is case-control. ECG tracings were requested for all children aged between one to twelve years who were hospitalized due to convulsion with no underlying etiology and simultaneously for children of the same age and gender who were admitted due to other than seizure as case group. Consequently, QT intervals were measured and compared in the two groups. Results: If long QT interval was defined to be longer than 0.47 second, no significant difference was noted between two groups. On the other hand, if this interval was defined to be equal to or longer than 0.46 second, long QT intervals are more frequent in convulsive children. Conclusions: In this study, long QT interval, defined as QT interval 0.46 second, is found more frequently in children with seizure than non-convulsing ones. It is recommended that children with history of seizure without any identifiable causes and that is unresponsive to anticonvulsive drugs should be investigated with ECG. Key words: Child, Diagnostic Errors, Long QT Syndrome, Seizure

Prevalence and Risk Factors of Prolonged QTc Interval among Chinese Patients with Type 2 Diabetes

Objectives. The aim of this study was to evaluate the prevalence and the risk factors of prolonged QTc interval among Chinese patients with type 2 diabetes. Methods. The retrospective study included 3156 outpatients from the Diabetes Centre, the 306th Hospital of PLA, during the period from September 2003 to June 2010. QT interval was measured manually in the 12-lead conventional electrocardiogram. The QT interval corrected for heart rate (QTc) was calculated using Bazett's formula. Additional demographic and laboratory data were also collected. Potential risk factors of prolonged QTc interval were assessed using multivariable regression. Results. The prevalence of prolonged QTc interval among Chinese patients with type 2 diabetes was 30.1%. Height (OR 0.156, 95% CI 0.032~0.748), waist circumference (OR 1.025, 95% CI 1.010~1.040), diastolic blood pressure (OR 1.016, 95% CI 1.007~1.026), postprandial glucose (OR 1.040, 95% CI 1.022~1.059), fasting insulin (OR 1.014, 95% CI 1.003~1.025), and presence of microalbuminuria (OR 1.266, 95% CI 1.033~1.551) were significant risk factors. Conclusions. The prevalence of prolonged QTc interval among Chinese patients with type 2 diabetes is high. Risk factors for prolongation of QTc interval were low height, high waist circumference, increasing diastolic blood pressure levels, high postprandial glucose levels, high fasting insulin levels, and presence of microalbuminuria.

49 Ethnic variation in QT interval among highly trained athletes

<h3>Background</h3> Studies in Caucasian (white) athletes indicate that a significant proportion exhibit an isolated prolonged corrected QT interval (QTc), raising concerns for potentially false diagnoses and disqualification from competitive sport. The prevalence of prolonged QTc interval in athletes of African/Afro-Caribbean (black) descent is unknown. However, this ethnic group generally exhibits a high proportion of ECG repolarisation changes and increased left ventricular wall thickness, that may impact on QTc. <h3>Aim</h3> We aimed to assess the impact of ethnicity on QTc in young elite athletes. <h3>Methods</h3> We assessed 3035 elite athletes, aged 14–35 years, who were participating at national and international level in a variety of sporting disciplines. Athletes were evaluated with ECG and 2D echocardiography. Athletes diagnosed with structural heart disease or hypertension were excluded from analysis. <h3>Results</h3> Demographic and cardiological results are summarised in Abstract 49 table 1. Black male athletes exhibited shorter QTc than white male athletes, but QTc was similar among black and white female athletes. Bivariate analysis revealed that none of T wave inversions, ST segment elevation, or left ventricular wall thickness were associated with QTc. No ethnic difference was observed in prevalence of QT prolongation, as defined by ESC Sports Consensus criteria (male &gt;440 ms; female &gt;460 ms). <h3>Conclusion</h3> Despite demonstrating a higher prevalence of repolarisation changes and morphological left ventricular hypertrophy, black athletes do not exhibit a longer QTc than white counterparts. Based on ESC Sports Consensus criteria, prevalence of a long QTc in black and white athletes is similar, obviating the need for ethnicity specific criteria for defining a long QTc.

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

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. 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. 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). 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.

Coronary heart disease and cardiac conduction abnormalities in persons with psychotic disorders in a general population

We investigated the prevalence of coronary heart disease (CHD) and myocardial infarction (MI) in persons with DSM-IV psychotic disorders. We also examined cardiac conduction abnormalities, and the role of antipsychotic medication in them. The study was based on a nationally representative survey of 8028 persons aged 30 years or over from Finland. Diagnoses of CHD and MI were based on electrocardiographic findings, health examination, and register information. QTc was calculated using the Bazett formula, and Minnesota classification was used for conduction abnormalities. We found that large Q-waves suggesting past MI were significantly more frequent in persons with schizophrenia, while the prevalence of CHD in persons with psychotic disorders did not differ significantly from the remaining study sample. Prevalence of prolonged QTc interval was significantly increased in persons with schizophrenia and in users of typical antipsychotics. However, low-potency antipsychotic use but not diagnosis of schizophrenia remained an independent predictor of prolonged QTc interval in a logistic regression. Low-potency antipsychotic use was associated with ventricular conduction defects, and high-potency antipsychotic use with premature beats. Symptoms and signs of CHD should be actively monitored patients with schizophrenia, and the electrocardiogram should be monitored for all types of changes in persons receiving antipsychotic medication.

QTc interval in a sample of long-term schizophrenia inpatients

This naturalistic study attempted to determine the prevalence of prolonged QTc interval in a relatively large population of inpatients hospitalized with chronic schizophrenia, and to explore QTc relationship with demographic variables, metabolic parameters and prescribed treatments. All inpatients from a Spanish long-term psychiatric hospital were cross-sectionally investigated to determine the prevalence of QTc prolongation and metabolic syndrome. The sample with a DSM-IV diagnosis of schizophrenia included 171 Caucasian inpatients, all of Spanish origin. A prolonged QTc interval was defined as >450 ms in men and >470 ms in women. The relationships between QTc and other continuous variables were assessed using a linear regression model with QTc as the dependent variable. Only 10 patients (6%) had a prolonged QTc interval; one case was possibly explained by hypokalemia. Three patients (2%) had a QTc > 500 ms. Gender, old age (≥50 years old), current smoking, systolic blood pressure, HDL cholesterol and history of arrhythmia were found to have significant effects on QTc interval in a linear regression analysis. After controlling for significant variables, the mean QTc interval was not significantly influenced by antipsychotic dose, type of antipsychotic treatment, the use of depot antipsychotics, or the number of different antipsychotics prescribed. Our study focused on long-term schizophrenia inpatients with frequent antipsychotic polypharmacy and high antipsychotic doses, and suggested that after excluding the case with hypokalemia length of QTc was associated with history of arrhythmias and with metabolic factors, while the effects of antipsychotic compound or class were not so evident.