QT Interval Abnormalities Research Articles

Assessment of QT Interval Abnormalities on Electrocardiogram in Children With Breath-Holding Spells

Assessment of QT Interval Abnormalities on Electrocardiogram in Children With Breath-Holding Spells

Genetic analyses of the electrocardiographic QT interval and its components identify additional loci and pathways

The QT interval is an electrocardiographic measure representing the sum of ventricular depolarization and repolarization, estimated by QRS duration and JT interval, respectively. QT interval abnormalities are associated with potentially fatal ventricular arrhythmia. Using genome-wide multi-ancestry analyses (>250,000 individuals) we identify 177, 156 and 121 independent loci for QT, JT and QRS, respectively, including a male-specific X-chromosome locus. Using gene-based rare-variant methods, we identify associations with Mendelian disease genes. Enrichments are observed in established pathways for QT and JT, and previously unreported genes indicated in insulin-receptor signalling and cardiac energy metabolism. In contrast for QRS, connective tissue components and processes for cell growth and extracellular matrix interactions are significantly enriched. We demonstrate polygenic risk score associations with atrial fibrillation, conduction disease and sudden cardiac death. Prioritization of druggable genes highlight potential therapeutic targets for arrhythmia. Together, these results substantially advance our understanding of the genetic architecture of ventricular depolarization and repolarization.

Study of QT interval prolongation in asymptomatic type-2 diabetes mellitus patients with and without microalbuninuria

QT interval abnormalities are the best predictors of cardiovascular deaths. Microalbuminuria is an independent marker for cardiovascular disease in diabetes mellitus. Hence QT interval abnormalities in diabetics with or without microalbuminuria were evaluated in this study. To study QT interval abnormalities in asymptomatic type 2 diabetic patients with or without microalbuminuria. : Open label controlled study with 214 subjects of either sex. Group A healthy subjects (n=100), group B asymptomatic, type 2 diabetics with no clinical evidence of cardiac disease. Group B subdivided into B with microalbuminuria (n=62), Bwithout microalbuminuria (n=52). Corrected QT interval (QTC), microalbuminuria, and blood pressure were measured for all subjects. QTC was calculated by using Bazzet's formula. QTC more than 440msec was considered prolonged. QTC was within normal range in diabetic patients(415+25msec). Highly significant (p<0.0001) prolongation was observed in diabetics, compared to healthy subjects. Both B(p<0.0001) and B(p<0.001) groups showed a significant increase in QTC than in healthy subjects. Among Band Bgroups QTC was not statistically significant. Prolongation of QTC is indicative of CAN. CAN is often under-recognised and undiagnosed cardiac complication.QTC was more in asymptomatic type 2 diabetics irrespective of microalbuminuria compared to healthy individuals, though values were within normal range. This denotes high risk for future cardiovascular complications in diabetic patients.

QT interval abnormalities and heart rate variability in patients with cirrhosis

Background and study aimsWe aimed to assess the relationship of the QT interval and heart rate variability with the severity and aetiology of cirrhosis and determine the effect of propranolol on them. Patients and methodsThis prospective study included 44 patients with cirrhosis categorised into three groups based on the Child–Pugh score: groups 1, 2 and 3 (with 12, 15 and 15 patients, respectively). Demographic characteristics, propranolol administration, severity of cirrhosis evaluated by the Child–Pugh score, aetiology of cirrhosis, and serum sodium, potassium and calcium levels were evaluated. All patients underwent 24 h-Holter monitoring. Corrected QT interval (QTc), average heart rate, standard deviation of normal-to-normal intervals (SDNN) and corrected SDNN (cSDNN) were evaluated. ResultsThe average QTc was significantly longer in group 3 than in groups 1 and 2 (453.4 ± 17.4 vs 422.8 ± 18.6 and 428.9 ± 17.24 ms, p < 0.001). The median SDNN was 70 ms and was significantly lower in group 3 vs groups 1 and 2 (77; interquartile range [IQR], 67–89.5 vs 57; IQR, 38–68 and 75 ms; IQR, 61–81 ms, p = 0.003). cSDNN was significantly lower in group 3 vs groups 1 and 2 (200.0 ± 42.6 vs 254.5 ± 75.3 and 277.8 ± 110.6 ms, p = 0.022). Propranolol administration resulted in a significant increase in the average SDNN value but had no effect on cSDNN or QTc. QTc was associated with the Child–Pugh class (p < 0.001), viral aetiology (p = 0.009) and sex (p = 0.010); SDNN was associated with the mean heart rate (p = 0.015) and Child–Pugh class (p = 0.024). ConclusionQTc interval prolongation and decreased SDNN are common in cirrhosis. Their prevalence is closely associated with disease severity. Propranolol has no effects on cSDNN or QTc.

QT interval and corrected QT interval in patients with sepsis in correlation with sepsis outcome and electrolytes

Abstract Background sepsis is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. Common signs and symptoms of sepsis include fever, increased heart rate, increased breathing rate, and confusion. In the very young, old, and people with a weakened immune system, there may be no specific symptoms. Aim to study QT dispersion, QT interval abnormalities and corrected QT interval in septic patients in correlation with arrhythmias, hospital outcome (survival, mortality) and electrolytes. Patients and Methodology this is a prospective randomized study that was conducted on forty adult patients who were admitted in the ICU at Ahmed Maher Teaching Hospital with the diagnosis of sepsis to correlate Corrected QT interval (QTc) and QT dispersion (QTD) with arrhythmias, need for mechanical ventilation (MV), electrolytes and hospital outcome. Results forty patients were included in this study, their ages with a mean of 53.50± 13.7 years. Male patients were 24(60%) and female patients were 16 (40%). The most frequent risk factor was hypertension (62.5%). Conclusions the QTc duration may act as a risk marker in the septic patient. Patients with markedly prolonged QTc interval had significantly more episodes of inhospital ventricular tachycardia and hospital mortality. Recommendations QTc may add a useful, simple and accessible tool to be used in risk stratification of septic patients. Factors that cause QTc prolongation could be an avoidable or correctable factors; lifethreatening arrhythmia could be prevented.

Palbociclib and ribociclib in breast cancer: consensus workshop on the management of concomitant medication.

Drug–drug interactions are of significant concern in clinical practice in oncology, particularly in patients receiving Cyclin-dependent kinase (CDK) 4/6 inhibitors, which are typically exposed to long-term regimens. This article presents the highlights from the ‘First Workshop on Pharmacology and Management of CDK4/6 Inhibitors: Consensus about Concomitant Medications’. The article is structured into two modules. The educational module includes background information regarding drug metabolism, corrected QT (QTc) interval abnormalities, management of psychotropic drugs and a comprehensive review of selected adverse effects of palbociclib and ribociclib. The collaborative module presents the conclusions of the five working groups, each of which comprised five experts from different fields. From these conclusions positive lists of drugs for treating common comorbid conditions that can be safely administered concomitantly with palbociclib and/or ribociclib were developed.

Validation of a smartphone-based electrocardiography in the screening of QT intervals in children.

OBJECTIVE:A 12-lead electrocardiography is a critical component for the screening of long QT syndrome; however, besides, an electrocardiograph, trained personnel are also necessary which limits the screening capability of conventional electrocardiographs. The development of smartphone electrocardiography technologies provides a potential alternative platform for electrocardiography screening for selective purposes such as arrhythmias and QT interval abnormalities. The aim of this pilot study was to assess the reliability of a smartphone-based electrocardiography device in the measurement of QT and corrected QT intervals in children.METHODS:In all participants, 10-s smartphone electrocardiography tracing from AliveCor device and a standard 12-lead electrocardiograph were obtained simultaneously. Two pediatric electrophysiologists performed the measurements of QT and corrected QT intervals in a blinded manner with Bazett’s formula. The results were compared statistically.RESULTS:A total of 285 children (mean age 9.8±4.9 years) who presented to our clinic were included in the study. The mean QT intervals obtained from 12-lead electrocardiographs and AliveCor devices were 343±40 ms and 340±41 ms, respectively. The mean corrected QT intervals obtained from 12-lead electrocardiographs and AliveCor devices were 419±28 ms and 415±33 ms, respectively. There was high correlation between the QT intervals of 12-lead electrocardiographs and AliveCor recordings (Pearson’s correlation coefficient: 0.83 [p<0.001]) and significant correlation between the corrected QT intervals of 12-lead electrocardiographs and AliveCor recordings (Pearson’s correlation coefficient: 0.57 [p<0.001]).CONCLUSION:AliveCor recordings can accurately detect QT intervals and can potentially be used for the screening of congenital long QT syndrome in children.

Prevalence of Electrocardiographic Patterns Associated With Sudden Cardiac Death in the Spanish Population Aged 40 Years or Older. Results of the OFRECE Study

Introduction and objectivesSome electrocardiographic patterns are associated with an increased risk of sudden cardiac death due to ventricular arrhythmias. There is no information on the prevalence of these patterns in the general population in Spain. The objective of this study was to analyze the prevalence of these patterns and associated clinical and epidemiological factors. MethodsThis subanalysis of the OFRECE study selected a representative sample of the Spanish population aged ≥ 40 years. We studied the presence or absence of electrocardiographic patterns of Brugada syndrome and QT interval abnormalities. Clinical data and electrocardiograms were available in all participants. Electrocardiograms were evaluated by 2 cardiologists and a third cardiologist was consulted if there was disagreement in the diagnosis. We calculated the weighted prevalence and clinical factors associated with the presence of Brugada-type patterns or QT segment abnormalities. ResultsOverall, 8343 individuals were evaluated (59.2 years, 52.4% female). There were 12 Brugada cases (type 1, 2 cases; type 2, 10 cases; weighted prevalence, 0.13%). For corrected QT (QTc) analysis, we excluded participants with left bundle branch block or without sinus rhythm. Weighted prevalences were as follows: short QTc (< 340ms) 0.18%, borderline QTc (441-469ms) 8.33%, long QTc (≥ 470ms criterion) 1.01% and long QTc (≥ 480 criterion) 0.42%. ConclusionsA total of 0.6% to 1.1% of the Spanish population aged ≥ 40 years has an electrocardiographic pattern associated with a higher risk of sudden death (Brugada syndrome, long QT, or short QT).

Prevalencia de patrones electrocardiográficos asociados a muerte súbita en la población española de 40 años o más. Resultados del estudio OFRECE

Introduction and objectivesSome electrocardiographic patterns are associated with an increased risk of sudden cardiac death due to ventricular arrhythmias. There is no information on the prevalence of these patterns in the general population in Spain. The objective of this study was to analyze the prevalence of these patterns and associated clinical and epidemiological factors. MethodsThis subanalysis of the OFRECE study selected a representative sample of the Spanish population aged ≥ 40 years. We studied the presence or absence of electrocardiographic patterns of Brugada syndrome and QT interval abnormalities. Clinical data and electrocardiograms were available in all participants. Electrocardiograms were evaluated by 2 cardiologists and a third cardiologist was consulted if there was disagreement in the diagnosis. We calculated the weighted prevalence and clinical factors associated with the presence of Brugada-type patterns or QT segment abnormalities. ResultsOverall, 8343 individuals were evaluated (59.2 years, 52.4% female). There were 12 Brugada cases (type 1, 2 cases; type 2, 10 cases; weighted prevalence, 0.13%). For corrected QT (QTc) analysis, we excluded participants with left bundle branch block or without sinus rhythm. Weighted prevalences were as follows: short QTc (< 340ms) 0.18%, borderline QTc (441-469ms) 8.33%, long QTc (≥ 470ms criterion) 1.01% and long QTc (≥ 480 criterion) 0.42%. ConclusionsA total of 0.6% to 1.1% of the Spanish population aged ≥ 40 years has an electrocardiographic pattern associated with a higher risk of sudden death (Brugada syndrome, long QT, or short QT).Full English text available from: www.revespcardiol.org/en

Electrocardiographic Changes in Patients with Isolated Traumatic Brain Injury and Their Correlation with Outcome

Objectives Electrocardiography (ECG) can be used as an inexpensive tool to identify high-risk patients who are at risk of developing cardiac dysfunction following traumatic brain injury (TBI). In the present article, we report our experience with the incidence of electrocardiographic changes in patients with TBI patients and their correlation with overall outcome. Materials and Methods All the patients who were admitted with the diagnosis of TBI under neurosurgery were included in the study. Clinical details and 12 lead ECG details for any ECG abnormalities (rhythm abnormalities, conduction abnormalities, QRS ST complex abnormalities, nonspecific ST changes, QT interval abnormalities, and data regarding outcome) were recorded. The data were entered into a spreadsheet and analyzed using StatsDirect version 3 statistical analysis software. Data were expressed using descriptive statistics—frequency and percentage for categorical variables. Pearson chi-square test was used to identify significance. p Results A total of 109 patients and same number of admission ECGs were available for interpretation. Mild head injury was most common (65.1%) followed by severe (18.3%) and moderate (15.6%) head injuries. ECG results were normal in 97 patients and were abnormal in 12 patients. Statistical analysis showed that the correlation among severity of the head injury, ECG results, and outcome was significant. However, there was no significant correlation between QTc and outcome, and correlation between severity of head injury and outcome. Conclusion The present study highlights the need to recognize the importance of ECG as a simple tool to identify the cardiovascular changes in patients with TBI. However, there is a need to conduct further prospective studies to supplement these findings with changes in the levels of cardiac enzymes or associated echocardiography abnormalities and their correlation with ECG findings and overall outcome.

The Contribution of National Spontaneous Reporting Systems to Detect Signals of Torsadogenicity: Issues Emerging from the ARITMO Project.

IntroductionSpontaneous reporting systems (SRSs) are pivotal for signal detection, especially for rare events with a high drug-attributable component, such as torsade de pointes (TdP). Use of different national SRSs is rarely attempted because of inherent difficulties, but should be considered on the assumption that rare events are diluted in international databases.ObjectiveThe aim was to describe TdP-related events associated with antipsychotics, H1-antihistamines and anti-infectives in three national SRSs (in Italy, Germany and France) and highlight potential signals of torsadogenicity through a combined literature evaluation.MethodsA common search strategy was applied to extract TdP-related events: (1) TdP, (2) QT interval abnormalities, (3) ventricular fibrillation/tachycardia, and (4) sudden cardiac death. Signals of disproportionate reporting (SDRs) were calculated for TdP + QT interval abnormalities and defined by a lower limit of the 95 % confidence interval of the reporting odds ratio (ROR) >1. Among SDRs with at least three cases without concomitant pro-arrhythmic drugs, we defined potential new signal of torsadogenicity as drugs with no published evidence from (a) the crediblemeds® website (http://www.crediblemeds.com, as of November 1st, 2014); (b) studies on the FDA Adverse Event Reporting System (FAERS); and (c) safety trials or pharmaco-epidemiological studies (as of December 16th, 2014).ResultsOverall, 3505 cases were retrieved (1372, 1468, and 801 for France, Germany and Italy, respectively). Antipsychotics were mainly recorded in Germany (792 cases), whereas antibiotics peaked at 515 and 491 (France and Italy, respectively). Forty-one drugs met criteria for SDRs in at least one single source, of which 31 were detected only from one single SRS: 18, ten and three (French, German and Italian SRS, respectively). By contrast, only five SDRs were detected in all national data sources (amisulpride, aripiprazole, haloperidol, olanzapine, risperidone). Overall, five potential new signals of torsadogenicity were identified: flupentixol, ganciclovir, levocetirizine, oxatomide and tiapride.ConclusionsWe found differences across and within national SRSs in the reporting of drug-induced TdP, which finally resulted in five potential new signals of torsadogenicity. These findings warrant targeted pharmacovigilance studies to formally assess the existence of actual drug–event associations.Electronic supplementary materialThe online version of this article (doi:10.1007/s40264-015-0353-1) contains supplementary material, which is available to authorized users.

Long-Term Impact of Different Immunosuppressive Drugs on QT and PR Intervals in Renal Transplant Patients.

Sudden cardiac deaths due to arrhythmias are thought to be an important cause of mortality in patients with renal transplants. Exposure to immunosuppressive drugs may lead to QT or PR interval abnormalities which may consequently cause arrhythmias. Our study investigated the long term impact of four different immunosuppressive drugs on PR and corrected QT intervals (QTc) in renal transplant patients The study population consisted of 98 kidney transplant recipients. Study patients were receiving immunosuppressive management with tacrolimus, cyclosporine A, everolimus or azathioprine according to the local protocols. QTc and PR intervals obtained from the most recent post-transplant electrocardiograms were compared with the pre-transplant intervals dated before the transplantation procedure. Post-transplant QTc intervals had prolonged significantly in comparison to the pre-transplant QTc intervals in all groups. However, there were no significant differences between the immunosuppressive agents with regard to post-transplant QTc interval prolongation (p > 0.05). There were no significant differences between the groups with regard to the pre and post-transplant PR interval changes (p > 0.05). QT interval prolongation, a marker of risk for arrhythmias and sudden death, is highly prevalent among kidney transplant patients receiving different classes of immunosuppressive drugs.

576: Evaluation of the fetal QT interval using non-invasive fetal ECG technology

QT-interval abnormalities in newborns are associated with hypoxia, maternal SSRI use, heart block, and Sudden Infant Death Syndrome. We sought to validate measurement of the fetal QT interval in term laboring women using non-invasive fetal ECG (NI-fECG) monitor (Mindchild Medical, North Andover, MA).

Antipsychotics and Torsadogenic Risk: Signals Emerging from the US FDA Adverse Event Reporting System Database

BackgroundDrug-induced torsades de pointes (TdP) and related clinical entities represent a current regulatory and clinical burden.ObjectiveAs part of the FP7 ARITMO (Arrhythmogenic Potential of Drugs) project, we explored the publicly available US FDA Adverse Event Reporting System (FAERS) database to detect signals of torsadogenicity for antipsychotics (APs).MethodsFour groups of events in decreasing order of drug-attributable risk were identified: (1) TdP, (2) QT-interval abnormalities, (3) ventricular fibrillation/tachycardia, and (4) sudden cardiac death. The reporting odds ratio (ROR) with 95 % confidence interval (CI) was calculated through a cumulative analysis from group 1 to 4. For groups 1+2, ROR was adjusted for age, gender, and concomitant drugs (e.g., antiarrhythmics) and stratified for AZCERT drugs, lists I and II (http://www.azcert.org, as of June 2011). A potential signal of torsadogenicity was defined if a drug met all the following criteria: (a) four or more cases in group 1+2; (b) significant ROR in group 1+2 that persists through the cumulative approach; (c) significant adjusted ROR for group 1+2 in the stratum without AZCERT drugs; (d) not included in AZCERT lists (as of June 2011).ResultsOver the 7-year period, 37 APs were reported in 4,794 cases of arrhythmia: 140 (group 1), 883 (group 2), 1,651 (group 3), and 2,120 (group 4). Based on our criteria, the following potential signals of torsadogenicity were found: amisulpride (25 cases; adjusted ROR in the stratum without AZCERT drugs = 43.94, 95 % CI 22.82–84.60), cyamemazine (11; 15.48, 6.87–34.91), and olanzapine (189; 7.74, 6.45–9.30).ConclusionsThis pharmacovigilance analysis on the FAERS found 3 potential signals of torsadogenicity for drugs previously unknown for this risk.Electronic supplementary materialThe online version of this article (doi:10.1007/s40264-013-0032-z) contains supplementary material, which is available to authorized users.

QT interval abnormalities: risk factors and perioperative management in long QT syndromes and Torsades de Pointes

Electrophysiological abnormalities of the QT interval of the standard electrocardiogram are not uncommon. Congenital long QT syndrome is due to mutations of several possible genes (genotype) that result in prolongation of the corrected QT interval (phenotype). Abnormalities of the QT interval can be acquired and are often drug-induced. Torsades de Pointes (TP) is an arrhythmia that is a result of aberrant repolarization/QT abnormalities. If not recognized and corrected quickly, QT interval abnormalities may precipitate potentially fatal ventricular dysrhythmias. The main mechanism responsible for the development of QT prolongation is blockade of the rapid component of the delayed rectifier potassium current (I kr), encoded for by the human-ether-a-go-go-related gene (hERG). The objectives of this review were (1) to describe the electrical pathophysiology of QT interval abnormalities, (2) to differentiate congenital from acquired QT interval abnormalities, (3) to describe the currently known risk factors for QT interval abnormalities, (4) to identify current drug-induced causes of acquired QT interval abnormalities, and (5) to recommend immediate and effective management strategies to prevent unanticipated dysrhythmias and deaths from QT abnormalities in the perioperative period.

Macrolides and Torsadogenic Risk: Emerging Issues from the FDA Pharmacovigilance Database

Introduction: Concern exists on the pro-arrhythmic potential of macrolides, namely Torsade de Pointes (TdP). Recent evidence has challenged the common opinion of considering azithromycin a safer therapeutic option, causing emerging regulatory and clinical interest. Materials and Methods: We analyzed cases of drug-induced TdP (2004-2011) submitted to the publicly available FDA Adverse Event Reporting System (FAERS). Four groups of mutually exclusive events were identified in decreasing order of drug-attributable risk: 1) TdP; 2) QT interval abnormalities; 3) ventricular arrhythmia (VA); 4) Sudden Cardiac Death (SCD). They were combined into case definition A (TdP/QT abnormalities) and case definition B (VA/SCD). Both case-by-case analysis (information on concomitant drugs, especially QT-prolonging agents listed by Arizona CERT, and disproportionality approach (Reporting Odds Ratio, ROR, with 95%CI) were carried out. Results: Over the 8-year period, macrolides were associated with 183 and 419 cases of interest (case definition A and B, respectively). Clarithromycin was the most frequently reported (84 and 162 cases), followed by azithromycin (63 and 140). Only 27% of cases of TdP/QT abnormalities with azithromycin occurred in patients >65 years of age (63, 47 and 44% for clari-, ery- and telithromycin, respectively). In cases of TdP/QT abnormalities, concomitant QT-prolonging drugs (Arizona CERT lists 1 or 2) were recorded with a proportion very different among macrolides (11 to 89%). The highest percentage of fatal outcome was recorded for azithromycin (17%). Disproportionality was found for azithromycin, clarithromycin and telithromycin for both events of interest, whereas erithromycin showed disproportion only for TdP/QT abnormalities. Conclusions: Despite inherent limitations of spontaneous reporting analyses, the remarkable proportion of fatal cases and the occurrence of TdP-related events in middle-aged patients strengthen the view that caution is needed before considering azithromycin as a safer therapeutic option among macrolides.

QT Interval prolongation and dispersion: Epidemiology and clinical correlates in subjects with newly diagnosed systemic hypertension in Nigeria

Background:The use of easily obtainable clinical and laboratory parameters to identify hypertensive patients with increased cardiovascular risk in resource limited settings cannot be overemphasized. Prolongation of QT intervals and increased dispersion has been associated with increased risk of cardiovascular death. The study aimed at describing the epidemiology of QT interval abnormalities among newly diagnosed hypertensive subjects and associated clinical correlates.Materials and Methods:One hundred and forty newly diagnosed hypertensive subjects and 70 controls were used for this study. Clinical and sociodemographic characteristics were obtained. Twelve lead resting electrocardiography, QT dispersion, heart rate corrected minimum and maximum QT intervals were determined manually. Increased QTcmax was defined at QTcmax >440msec. QT parameters were compared between various groups. SPSS 16.0 was used for data analysis.Results:The hypertensive subjects were well matched in age and gender distribution with controls. QTmax and QTcmax were significantly higher among hypertensive subjects than controls (379.7±45.1 vs. 356.7±35.6, 447.5± 49.0 vs. 414.5 ±34.7 ms, respectively, P<0.05). QTd and QTcd were also significantly higher among hypertensive subjects than controls (62.64±25.65 vs. 46.1±17.2, 73.8 ±30.0 vs. 52.5±18.8, respectively, P<0.05). Seventy three (52.14%) of the hypertensive subjects had QTcmax >440ms compared to 21.43% of controls, P=0.01. Increased QTc dispersion was present in 36.4% of hypertensive subjects. Hypertensive subjects with QT abnormalities had significantly higher mean waist hip ratio, mean body mass index and a higher proportion of smoking than controls.Conclusion:QT prolongation and increased QTc dispersion are common among newly diagnosed hypertensive Nigerians and seem to be significantly associated with obesity. Effective antihypertensive therapy and control of obesity are important management modality for newly diagnosed hypertensive patients.

QT interval shortening in spontaneous reports submitted to the FDA: the need for consensus

QT interval shortening in spontaneous reports submitted to the FDA: the need for consensus

QTc‐interval abnormalities in a forensic population

Antipsychotic drugs have been linked to sudden death among psychiatric patients, with a suggestion that prolongation of the QT-interval detectable on a standard electrocardiogram may be linked to fatal cardiac arrhythmias in these circumstances. Patients in secure forensic psychiatric facilities may be particularly likely to be on high-dose antipsychotic medication, and yet, as far as the authors are aware, no study of QT-intervals among such patients has been reported. To investigate the prevalence of QT-interval abnormalities and associated known risk factors for fatal cardiac arrhythmias in a sample of forensic patients. Participants had a 12-lead electrocardiogram taken at 50 mm/s. Information was collected on their age, gender, psychiatric diagnosis, history of cardiovascular, liver and kidney diseases, and smoking, on all medications and on history of seclusion over the previous 12 months. Analysis was carried out using binary logistic regression. Lower rates of QT-interval abnormalities than might be expected for this population were found. It was also found that a high dose of antipsychotics was associated with QTc prolongation (Adjusted OR = 9.5, 95% CI 2.6-34.2), a result consistent with previous literature. Forensic patients need not be at increased risk of QTc abnormality provided risk factors are properly managed. A high dose of antipsychotic medication increases the risk of QTc prolongation.

Fetal Cardiac Repolarization Abnormalities

Abnormal cardiac repolarization renders the heart susceptible to lethal ventricular tachyarrhythmias, increasing the risk of sudden cardiac death in all ages; however, little is known about the incidence and etiology of T-wave abnormalities in utero. In this study, magnetocardiography was used to better define fetal T-wave characteristics, including the QT interval in the normal fetus, and to characterize T-wave abnormalities in the fetus with arrhythmia. The QT interval and T-wave alternans were assessed from magnetocardiographic recordings obtained at 14 to 39 weeks' gestation from 120 fetuses. Of these fetuses, 78 were from uncomplicated pregnancies and 42 had various forms of fetal arrhythmia (supraventricular tachycardia in 14, congenital atrioventricular block in 17, long QT syndrome with Torsades de pointes in 1, ventricular tachycardia in 2, sinus bradycardia in 4, and bradycardia due to blocked premature atrial contractions in 4). Although the corrected QT interval in normal sinus rhythm was accurately described by Bazett's formula, the corrected QT interval in fetal arrhythmia exhibited a systematic deviation at heart rate extremes. The dependence of the QT interval on the RR interval in arrhythmia was approximately described by QT alpha RR0.8. T-wave alternans was detected in 7 fetuses with arrhythmia, often in association with QT prolongation, suboptimal outcome, or fetal demise. The results of our study have demonstrated that QT-interval abnormalities exist and can be detected in fetal patients. The potential importance of T-wave assessment in the fetus with cardiac arrhythmia was evidenced by the high incidence of marked QT prolongation and T-wave alternans in the fetuses with suboptimal outcomes.