Prevalence Of QTc Prolongation Research Articles

Determinants/Predictors of QT Abnormalities in Patients on Psychotropic Medications in a Nigerian Tertiary Hospital.

Cardiovascular disease is a major global burden and a leading cause of premature death among patients with severe mental illness. Over time, research and clinical practice have paid increased attention to the impact of psychiatric medications on cardiac repolarization. In a resource-limited setting, it is common for psychotropic medications to be initiated and maintained in an outpatient setting without baseline or follow up ECG. This study evaluated the determinants and predictors of QT abnormalities among patient taking psychotropic drugs. We conducted a cross-sectional study in a population of 150 psychiatric patients on psychotropics and 75 controls. We studied the effects of various psychotropic drugs on QT dispersion (QTd) and corrected QT interval (QTc) as well as correlation with the types and dosages of psychotropic drugs used. All the subjects had detailed clinical examination and resting electrocardiogram (ECG) at 25mm/sec done. QTc was determined using Bazett formula and QTd was determined by subtracting shortest from longest QT in 12-lead ECG. The prevalence of prolonged QTc and QTd as well as the mean QTc and QTd were significantly higher in patients than the control group. The mean QTc was significantly higher in patient on typical antipsychotics compared to those on atypical antipsychotics. Age, heart rate and antipsychotic dose in chlorpromazine equivalent were predictors of QTc with the heart rate being the most powerful predictor among them. Psychotropic drugs use is associated with QTc and QTd prolongation with age, heart rate and antipsychotic dose as predictors of QTc.

Bioelectrical Impedance Phase Angle Value and Prolongations of PR and Corrected QT Intervals in Patients Undergoing Dialysis

Introduction: Phase angle value, derived from bioelectrical impedance analysis, represents the body cell mass and nutritional status of patients undergoing hemodialysis. Although the phase angle value has clinical significance in these patients, its relationship with electrocardiogram (ECG), another clinically relevant bioelectrical examination, has not yet been well clarified. Methods: Two hundred and twenty-four patients undergoing dialysis (80 females and 144 males; mean ± SD, 72.2 ± 12.0 years old; 117 diabetic and 107 nondiabetic patients) were studied retrospectively. Multifrequency bioelectrical impedance analysis was performed immediately after the end of dialysis therapy. The phase shift was geometrically converted into a phase angle value. The ECG was recorded simultaneously, and the upper limits of the PR interval, QRS width, and corrected QT interval (QTc) were set at 0.20, 0.12, and 0.44 s, respectively. The geriatric nutritional risk index (GNRI), a representative nutritional index, was also determined. In addition, we examined the incidence of cardiac events, including heart failure, myocardial infarction, cardiac revascularization procedure, cardiac arrhythmia, and cardiac death, or all-cause death. Results: Of 224 patients undergoing dialysis, the prolongation of the PR interval, QRS width, and QTc was found in 30.7, 17.4, and 62.1%, respectively. The prevalence of QTc prolongation was higher in females and diabetic patients than in males and nondiabetic patients. An inverse relationship between phase angle value and QTc was observed only in males and nondiabetic patients. The relationships of GNRI both with phase angle value and QTc were stronger in males and nondiabetic patients. In addition, PR interval was inversely correlated with a phase angle value only in nondiabetic patients. No significant correlation was found between phase angle value and QRS width. Five-year survival probability for the composite endpoints was significantly worse in patients with lower phase angle values. QTc prolongation was associated with survival in males and nondiabetic patients. Prolonged PR was associated with survival in nondiabetic patients. Discussion: Relationships between phase angle value and ECG findings were demonstrated in patients undergoing dialysis, especially in males and nondiabetic patients. Although the phase angle value has been considered as an index for evaluating nutritional status, another clinical application of phase angle value in predicting cardiac complications seems to be useful.

Determinants of severe QTc prolongation in a real-world gerontopsychiatric setting.

QTc prolongation carries the risk of ventricular tachyarrhythmia (Torsades de Pointes) and sudden cardiac death. Psychotropic drugs can affect ventricular repolarization and thus prolong the QTc interval. The present study sought to investigate the risk factors (pharmacological and non-pharmacological) of severe QTc prolongation in gerontopsychiatric patients. Electrocardiograms of patients on a gerontopsychiatric ward were screened for QTc prolongation. Medication lists were examined utilizing the AzCERT classification. Potential drug interactions were identified with the electronic drug interaction program mediQ. The overall prevalence of QTc prolongation was 13.6%, with 1.9% displaying severe QTc prolongation (≥ 500 ms). No statistically significant differences between patients with moderate and severe QTc prolongation were identified; however, patients with severe QTc prolongation tended to take more drugs (p = 0.063). 92.7% of patients with QTc prolongation took at least one AzCERT-listed drug, most frequently risperidone and pantoprazole. Risperidone and pantoprazole, along with pipamperone, were also most frequently involved in potential drug interactions. All patients displayed additional risk factors for QTc prolongation, particularly cardiac diseases. In addition to the use of potentially QTc-prolonging drugs, other risk factors, especially cardiac diseases, appear to be relevant for the development of QTc prolongation in gerontopsychiatric patients. Pantoprazole was frequently involved in potential drug interactions and should generally not be used for more than 8 weeks in geriatric populations. As clinical consequences of QTc prolongation were rare, potentially QTc-prolonging drugs should not be used overcautiously; their therapeutic benefit should be considered as well. It is paramount to perform diligent benefit-risk analyses prior to the initiation of potentially QTc-prolonging drugs and to closely monitor their clinical (side) effects.

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.

Serial assessment of corrected qt interval and its clinical correlates in patients receiving psychotropic medications

Background &amp; Aims: Psychotropic medications vary in propensity to cause QTC prolongation on electrocardiogram. It can be fatal sometimes. Prospective Indian studies in this area are lacking. Present study was conducted to prospectively assess the changes in QTC in patients receiving psychotropic medications. Settings and Design: Hospital based prospective observational study. Methods: A total of 150 patients aged 18-60 years, diagnosed as having any psychiatric illness and receiving psychotropic medications formed the sample. Psychiatric diagnosis was made according to DSM-5. Baseline ECG was done and psychotropic medications as per the diagnosis of the patient were started. Serial ECGs were performed on them up to one month post treatment. Results: Females constituted 54.7% of the sample. Major Depressive Disorder was the most common diagnosis. The duration of illness was less than 6 months in 47.3% of the patients. The dose of all psychotropic medications prescribed were in the therapeutic range and none of them exceeded the recommended maximum dose. Psychotropic medication was associated with increase in QTC from baseline. The prevalence of QTC prolongation was 1.40% at first follow up and 15% at second follow up. It ranged between 1 ms to 21 ms.

QTc prolongation in adolescents with acute alcohol intoxication

In adults, alcohol intoxication is associated with prolongation of the QT interval corrected for heart rate (QTc). The QTc is influenced by age and sex. Although alcohol intoxication is increasingly common in adolescents, there are no data on the prevalence of QTc prolongation in adolescents with alcohol intoxication. This study aimed to determine the prevalence of QTc prolongation in adolescents with alcohol intoxication and identify at-risk adolescents. In this observational study including adolescents aged 10–18 years, heart rate and QT interval were automatically assessed from an electrocardiogram (ECG) at alcohol intoxication using a validated algorithm. The QTc was calculated using both the Bazett formula (QTcB) and Fridericia formula (QTcF). If present, an ECG recorded within 1 year of the date of admission to the emergency department was obtained as a reference ECG. A total of 317 adolescents were included; 13.3% had a QTcB and 7.9% a QTcF longer than the sex- and age-specific 95th-percentile. None of the adolescents had a QTcB or QTcF > 500 ms, but 11.8% of the adolescents with a reference ECG had a QTcB prolongation of > 60 ms, while no adolescents had a QTcF prolongation of > 60 ms. QTc prolongation was mainly attributable to an increase in heart rate rather than QT prolongation, which underlies the differences between QTcB and QTcF. Male sex and hypokalaemia increased the likelihood of QTc prolongation.Conclusion: QTc prolongation was seen in approximately 10% of the adolescents presenting with alcohol intoxication, and although no ventricular arrhythmias were observed in this cohort, QTc prolongation increases the potential for malignant QT-related arrhythmias. Clinicians must be aware of the possibility of QTc prolongation during alcohol intoxication and make an effort to obtain an ECG at presentation, measure the QT interval, and give an adequate assessment of the findings. We advocate admitting adolescents with alcohol intoxication and QTc prolongation. During hospital admission, we recommend limiting exposure to QTc-prolonging medication, increasing potassium levels to a high-normal range (4.5–5.0 mmol/L) and obtaining a reference ECG at discharge.What is Known:• One out of five deaths in adolescents is alcohol-related. Alcohol intoxication has been related to cardiac arrhythmias and sudden cardiac death.•In adults, alcohol intoxication is associated with QTc prolongation.What is New:•Approximately 10% of the adolescents with alcohol intoxication had a QTc longer than the age- and sexspecific cut-off. In contrast to adults, in adolescents with alcohol intoxication, QTc prolongation is attributable to an increase in heart rate, rather than a prolongation of the QT interval.•Especially males and adolescents with hypokalaemia are at risk of QTc prolongation.

A study of serum calcium level in cases of malaria in a tertiary care hospital

Background: Malaria is a tropical disease caused by Plasmodium species, commonly P. falciparum and P. vivax. Carpopedal spasm has been noted in many patients presenting with malarial fever. Most of the patients are later found to have hypocalcaemia. Hypocalcaemia associated with malaria can cause many clinical manifestations, including life threatening conditions such as arrhythmias, convulsions etc.Methods: A cross-sectional study was conducted with the aim to determine the prevalence and clinical profile of hypocalcaemia in different types of malarial fever. 88 patients of malarial fever were studied. Patients were stratified according to the species of plasmodium and into complicated and uncomplicated malaria. Total serum calcium level and QTc interval were analysed in each patient. Data collected were analysed.Results: Prevalence of hypocalcaemia in malaria was found to be 54.45% in our study. Hypocalcaemia was more prevalent in complicated malaria than uncomplicated malaria. Complicated falciparum malaria showed highest prevalence of hypocalcaemia. Status of complexity of malaria was not found to be related to occurrence of hypocalcaemia in any types of malaria. Prevalence of QTc prolongation in malaria was found to be 48.46%. Prevalence of QTc prolongation was found to be more in complicated malaria than uncomplicated malaria. QTc prolongation was most prevalent in complicated falciparum malaria. 83.3% of those with QTc prolongation had hypocalcaemia.Conclusions: Hypocalcemia and QTc prolongation were more prevalent in complicated malaria than in uncomplicated malaria. Both Hypocalcaemia and QTc prolongation were most prevalent in complicated falciparum malaria.

The Risk of QTc Prolongation in Non-Diabetic and Diabetic Patients Taking Tyrosine Kinase Inhibitors (TKIs)- A Patient Safety Project at a Private Oncology Practice

ABSTRACT Objective: To assess the prevalence of QTc prolongation in both non-diabetic and diabetic patients on TKIs. Some TKIs have been reported to cause QTc prolongation, which is prevalent in diabetes. However, there is no Risk Evaluation and Mitigation Strategy using series ECG to monitor those patients. Methods:Patients taking TKIs, with two ECGs recorded between 1 January 2010 and 31 December 2017 were selected from the electronic database. The QTc duration >450 ms was determined as prolonged. Percentage of QTc prolongation on participants were compared using Chi-Square test. Results:This study included 313 patients (age 66.1 ± 0.8 years and 57.5% are female) taking TKIs. In non-Diabetic patients, the prevalence of QTc prolongation is 19.1% (n = 253) before and 34.8% (n = 253) after treatment with TKIs (p < 0.001), respectively. In diabetic patients, the prevalence of QTc prolongation is 21.7% (n = 60) before and 40% (n = 60) after treatment with TKIs (p = 0.03), respectively. In addition, we examined the effect of modifying risk factors for cardiovascular disease (CVD) on the prevalence of QTc prolongation caused by TKIs. In non-diabetic patients, the prevalence of QTc prolongation is 33.3% (n = 57) before and 34.2% (n = 196) after risk factors modification (p = 0.91), respectively. In diabetic patients, the prevalence of QTc prolongation is 50% (n = 24) before and 33.3% (n = 36) after risk factors modification (p = 0.20), respectively. Conclusion:Use of TKIs is associated with a significantly increased risk of QTc prolongation for patients, particularly when patients are diabetic. Modification of risk factors for CVD does not significantly affect the prevalence of QTc prolongation caused by TKIs.

DPP4 inhibitors as a risk factor for QTC interval prolongation among type 2 diabetic patients

Abstract Introduction Prolonged QT interval is associated with cardiac arrhythmias and sudden death. This study determined the prevalence of QT intervals corrected for heart rate (QTc) among adults admitted for executive check up in a tertiary hospital with Type 2 diabetes and its associations with metabolic control. Methods This cross-sectional study included 111 adult patients with Type 2 diabetes and 152 control patients admitted for executive check up in a tertiary hospital. A standard 12-lead electrocardiogram was recorded. Corrected QT interval (QTc) of &amp;gt;440 ms was considered abnormally prolonged and QTc &amp;gt;500 ms was considered a high-risk QTc. Demographic, clinical and laboratory data were collected. Independent risk factors for prolonged QTc were assessed using logistic regression analysis. Results QTc duration was statistically significant between subjects with Type 2 diabetes and control subjects (mean duration 434 vs 419 ms; P=0.003). Prevalence of prolonged QTc among type 2 diabetics is 41.4% and 28% in the control group. In the diabetic group 2.7% has a QTc of &amp;gt;500. Independent risk factors for prolonged QTc using univariate logistic regression analysis is presence of diabetes type 2 (OR = 2.00, p=0.008), HBA1c (OR = 1.23, p=0.050) and intake of DPP4 (OR=6.46, (p≤0.001). Independent risk factors for prolonged QTc using multivariate logistic regression analysis is intake of DPP4 inhibitors (OR=6.26, p=0.023). Conclusion There is no significant correlation between HBA1C and QTc interval. The prevalence of prolonged QTc is relatively high among diabetics but the prevalence of high risk QTc interval is relatively low. Intake of DPP4 inhibitors is an independent risk factor in QT prolongation. Funding Acknowledgement Type of funding sources: None.

The Prevalence, Risk Factors and Clinical Correlates of QTc Prolongation in Chinese Hospitalized Patients With Chronic Schizophrenia.

Background: The QTc interval may be significantly prolonged in schizophrenia patients taking antipsychotics. Few studies have addressed QTc prolongation (QTP) in Chinese patients.Objectives: This study was designed to evaluate the prevalence of QTP and its clinical correlates in Chinese hospitalized patients with chronic schizophrenia.Methods: A total of 436 inpatients and 291 normal controls matched with age and sex were included. QTc prolongation was defined as 2 standard deviations (SD) above the mean value of normal controls. Positive and Negative Syndrome Scale (PANSS) and its five-factor model were used to evaluate psychopathological symptoms.Results: QTc interval was significantly longer in patients than in normal controls. The prevalence of QTP is 8.26% in Chinese hospitalized patients with chronic schizophrenia. More women than men displayed QTP. Compared with patients without QTP, the patients with QTP had significantly higher concrete/disorganized subscore, lower low density lipoprotein (LDL) and lower total protein (TP). Furthermore, binary logistic regression analysis showed that higher number of hospitalizations, higher concrete/disorganized subscore and lower LDL were risk factors for QTP. Correlation analysis indicated significant association between QTc interval and the following variables: sex, age, duration of illness, the number of hospitalizations, PANSS total score, fasting blood glucose (FPG). Finally, a multiple regression analysis showed that older age, antipsychotic polypharmacy, higher PANSS total score, and lower LDL were risk factors for QTP. Among them, LDL seemed to be a protective factor for QTP.Conclusions: QTc interval was longer in schizophrenia patients than in normal controls. The prevalence of QTP is 8.26% in Chinese hospitalized patients with chronic schizophrenia. Some clinical characteristics were risk factors for QTP. And LDL seemed to be a protective factor for QTP.

Prevalence of discordant QTc values among cancer patients by the Bazett, Fridericia, and Framingham formulae: Evidence for a standardized approach.

6575 Background: Many chemotherapies have the potential to prolong the QT interval, requiring monitoring of the corrected QT (QTc) to prevent life-threatening arrhythmias. Most clinical guidelines recommend adjusting/holding chemotherapy with Grade 3 or higher toxicity by CTCAE (QTc≥500). Several formulae are used for QTc monitoring including Bazett, Fridericia, and Framingham. The most commonly used formula, Bazett, is well-documented to result in inappropriately high QTc values although the potential impact of this overcorrection on cancer treatment is unknown. We aimed to describe the prevalence of QTc prolongation among cancer patients and the effects on CTCAE adverse event grading by various QTc formulae to determine the potential impact on clinical management. Methods: We performed a single-center retrospective analysis of QT values from electrocardiograms (ECGs) collected January 2010-April 2020 and evaluated associations between QTc values, medications, and patient characteristics. QTc prolonging agents were determined by FDA package insert and cross-referenced with CredibleMeds.org. Results: 20,017 ECGs were evaluated. 18.6% (3,730) met ACC/ACCF/HRS criteria for prolonged QTc by ≥1 QT correction formula (either Bazett, Fridericia, or Framingham). 7.5% (1,494) were prolonged with all three formulae, and 8.6% (1,635) were prolonged only with Bazett. The CTCAE classification using the Bazett formula differed from both Fridericia and Framingham in 37.9% (7,583) of the ECGs. In contrast, Fridericia and Framingham formulae resulted in the same CTCAE classification in 94.5% (18,912). Of 1,789 ECGs classified as Grade 3 toxicity by Bazett, 72.0% (1,288, 6.4% of all ECGs) were classified as Grade 2 or less by both Fridericia and Framingham. 12.0% (2,340) of all ECGs were taken from patients (n = 421) on 24 different QT-prolonging chemotherapies. In 38.8% (909) of the ECGs, the CTCAE classification using the Bazett formula differed from both Fridericia and Framingham while use of Fridericia and Framingham formulae resulted in the same classification in 93.0% (2,176) of the ECGs. Of 293 ECGs classified as Grade 3 toxicity by Bazett, 65.2% (191) were classified as Grade 2 or less by both Fridericia and Framingham. Conclusions: To our knowledge, this is the largest analysis of discrepancies between different QTc formulae in patients receiving chemotherapy. These findings demonstrate an unacceptably high rate of discordance between formulae. Discordant data can lead to inconsistent clinical management and adverse event grading underscoring the urgent need to standardize QTc monitoring and reporting. These findings support the discontinuation of the routine use of the Bazett correction formula among cancer patients as CTCAE Grade 3 reporting from the Bazett formula is unreliable in over 65% of cases.

QTc prolongation in patients with COVID-19: a retrospective chart review.

Drug-induced corrected QT (QTc) prolongation can cause Torsade de Pointes (TdP) which leads to severe arrhythmia or sudden cardiac death. However, information on the prevalence of QTc prolongation in coronavirus disease 2019 (COVID-19) patients and risk factors is limited. A retrospective chart review was conducted in COVID-19 patients admitted to Chonburi Hospital from April to October 2020. The outcomes were the incidence of QTc prolongation and prevalence of risk factor QTc prolongation. We included 29 COVID-19 patients. After treatments were initiated, QTc prolongation occurred in 17 patients (58.62%). QT prolongation could be found as early as two days after the treatment initiation (median = 6 days interquartile range [IQR], 4–7). The median QTc interval in those 17 patients increased from 410 (IQR, 399.5–425.0) ms to 460 (453.50–466.50) ms, with the maximum QTc interval of 488 ms. They were treated with multiple drugs that were reported as a cause of QTc prolongation. 64.71% (n = 11) of them were treated with chloroquine. The median TdP risk score in patients with and without QTc prolongation was 3 (IQR, 2–3) and 2 (IQR, 1–2), respectively. The percentage of patients with comorbidities including atrial fibrillation, bradycardia, concomitant use of diuretics, diabetes, electrolyte imbalance was higher in patients with QTc prolongation. COVID-19 patients were treated with multiple drugs that were reported as a cause of QTc prolongation. COVID-19 patients with QTc prolongation had more comorbidities that are risk factors for QTc prolongation.

Changes in QTc and PR Intervals among Indian Type 2 Diabetes Patients with Respect to Prevailing Glycated Hemoglobin Level: a Retrospective Analysis

Cardiovascular complications in patients with type 2 diabetes mellitus (T2DM) account for a considerable proportion of patients’ mortality. The analysis was done primarily to assess the prevalence of prolonged QTc and PR intervals and to test their association with changes in glycated hemoglobin (HbA1c) values and other demographic and clinical characteristics among Indian diabetic patients. A single-center retrospective study was conducted involving clinical records of all diabetic patients having a routine 12-lead resting electrocardiogram (ECG) investigation from Jan 2019 to July 2019 at the outpatient department of our medical care center. The association between QTc and PR intervals and the following demographic and clinical variables were assessed: age, systolic (SBP) and diastolic blood pressure (DBP), glycated hemoglobin (HbA1c), and estimated glomerular filtration rates (eGFR). The records of 324 patients were included and were found to have 51.5% females, mean age of 53.78 ± 11.98 years, median QTc: 395.63 ms (223–474) and median PR: 152.02 ms (100–240). The prevalence of prolonged QTc (as defined by a value of > 440 ms) and PR intervals (as defined by a value of > 200 ms) were 4.6% (95% confidence interval [CI], 2.34 to 6.92) and 1.5% (95% CI, 0.20 to 2.89), respectively. Patients’ genders and ages significantly affected ECG findings, while other metabolic and clinical parameters had not conferred a significant role in modulating the risk of cardiovascular disease in the current cohort. Prospective studies with larger sample sizes and employing additional parameters are warranted. The study also showed a high prevalence of hypertension in a diabetic population (60.2%) and a nephropathy burden of 14.5%.

Qtc interval prolongation during targeted therapy with tyrosine kinase inhibitors for patients with chronic myeloid leukemia

Background The advances in the treatment of chronic myeloid leukemia using tyrosine kinase inhibitors have led to unequivocal improvement in the survival of those patients. However, the effect of tyrosine kinase inhibitors on cardiac repolarization causing QT interval prolongation and the potential risk of life-threatening arrhythmia Torsade de pointes poses a challenging risk.Objective The objective of this study was to assess the prevalence of QTc interval prolongation in patients with chronic myeloid leukemia receiving imatinib or nilotinib therapy.Patients and methods A total of 43 patients were included in this cross-sectional study, where 22 patients were on nilotinib and 21 patients were on imatinib. Electrocardiogram was done for patients while on tyrosine kinase inhibitors (TKI) therapy. Corrected QTc interval was assessed using Bazett’s formula.Results The prevalence of QTc prolongation in the total cohort of patients was 46.5%. Moreover, 23.3% of patients had QTc more than or equal to 500 ms. The mean QTc in patients receiving imatinib was 467 ms, whereas the mean QTc in patients on nilotinib was 433.5 ms, with a statistically significant difference (P=0.033). Overall, 61.9% of patients on imatinib had prolonged QTc compared with 31.8% of patients on nilotinib, with a statistically significant difference (P=0.048). However, although nonstatistically significant, the median QTc percentage prolongation for patients on nilotinib is 10.8 compared with 5.1 for patients on imatinib. No statistically significant sex difference was found; however, the mean QTc was higher in females (455.93 ms) compared with males (439.69 ms) (P=0.327). No significant difference was found between QTc and duration of TKI use or correlation between QTc and age.Conclusion The prevalence of QTc prolongation is significantly increased in patients with chronic myeloid leukemia (CML) treated with either imatinib or nilotinib. ECG monitoring in those patients is strongly recommended to prevent life-threatening arrhythmias.

Prevalence of QTc Prolongation in Patients With Advanced Cancer Receiving Palliative Care—A Cause for Concern?

ContextMedications commonly used for symptom control along with other known risk factors have the potential to prolong ventricular repolarization as measured by the QT interval (the time from the start of the Q wave to the end of the T wave) on a standard electrocardiogram (ECG). ObjectivesTo document the prevalence of a prolonged QT interval corrected for heart rate (QTc) interval in the palliative/oncology setting, compare automatic ECG QTc measurements with manual readings and identify any correlation between QTc prolongation and the use of drugs or other risk factors. MethodsA convenience sample of consecutive patients with cancer, admitted under or known to the palliative/supportive care teams in two metropolitan hospitals, and willing to provide an ECG recording and basic demographic information including QTc risk factors were included. Both automated and manually calculated QTc intervals were recorded. Multivariable analysis was used to determine risk factors independently associated with prolonged QTc intervals. ResultsOf the 389 participants, there was a significant difference in mean QTc between sites using automated but not manual calculations. Manual readings were therefore used with predetermined cutoffs of 0.44 seconds (males) and 0.46 seconds (females). Seventy-two (18.5%) of the participants had a prolonged QTc with six (1.5%) having a prolongation of >0.50 seconds. At-risk drugs were being taken by 218 participants (56.0% of total cohort). Factors shown to be associated with QTc prolongation included age, gender, performance status, and hypocalcemia. No specific medication was associated with increased risk. ConclusionAlthough almost 20% of patients receiving palliative care had prolongation of QTc, the possibility of serious consequences appeared to be low despite the frequent occurrence of risk factors.

Risk Factors and Prevalence of QTc Prolongation in Adult Burn Patients Receiving Methadone.

Methadone is an opioid commonly used for acute pain management in burn patients. One adverse effect of methadone is QTc interval prolongation, which may be associated with adverse cardiac outcomes. There is currently a paucity of data regarding risk of QTc prolongation in burn patients taking methadone and a lack of evidence-based recommendations for monitoring strategies in this population. The study objective was to determine the prevalence, risk factors, and cardiac outcomes related to methadone-associated QTc prolongation in adult burn patients. A total of 91 patients were included and were divided into groups according to maximum QTc. QTc prolongation was defined as greater than or equal to 470 ms (males) or 480 ms (females). There were no differences between groups regarding patient-specific risk factors, baseline QTc, or time to longest QTc. Patients in the prolonged QTc group had a higher rate of cardiac events (44% vs 9%; P < .001), higher median (IQR) change from baseline to longest QTc (61 ms [18,88] vs 23 ms [13,38]; P < .001), higher median (IQR) total daily dose of methadone (90 mg [53,98] vs 53 mg [30,75]; P = .004), and longer median (IQR) length of stay (53 [33,82] vs 35 [26,52] days; P = .008). QTc prolongation in burn patients was associated with increased methadone dose and resulted in a higher rate of cardiac events. This study was the first of its kind to look at risk factors and cardiac outcomes associated with methadone use in burn patients.

P6583Prevalence of long QT interval in thailand and its association with all cause and cardiovascular mortality from a long-term cohort study

Abstract Background Long QT interval elevates risks of life-threatening arrhythmias, cardiovascular mortality and all-cause mortality. The prevalence of prolonged QTc among Caucasians is approximately 8.7%. In Thai population, the prevalence and prognosis of prolonged QTc remain unexplored. Objectives 1. To identify the prevalence of long QT interval in the Thai population without prior cardiovascular disease. 2. To evaluate the association between long QT interval and long-term cardiovascular (CV) event and all-cause mortality. Materials and methods A total of 2756 participants from the Electricity Generating Authority of Thailand (EGAT) study from 1997 to 2015 were studied. Among those, 2456 participants had completed EKGs and were included into the final analysis. The long QT interval was defined as QTc longer than 450 milliseconds (ms) in male and 460 ms in female respectively. Mortality endpoints included CV event and all-cause mortality were collected. Multivariable cox-proportional hazard model adjusted for all major CV risk factors was used to determine the association between prolonged QTc and outcomes. Results The majority of the population are male (N=1941, 79%). The mean QT interval calculated by Bazett's formula is 424±28.27 ms. Prolonged QTc was observed 12.5% in male and 17.7% in female. There were 509 (20.7%) deaths during the follow-up period. After 18 years of follow up, 10.5% of the prolonged QTc group had cardiovascular events, compared with 6.8% in the normal QTc group (P=0.09). All-cause mortality occurred in 30% of the prolonged QTc group and 19.3% in the normal QTc group (adjusted HR 1.33, 95% CI 1.05–1.68, P=0.018). After dividing QTc into deciles, the lowest mortality was observed in the 3rd to 7th deciles (17.6%, 19.7%, 16.3%, 23.2% and 18.9% respectively) and the highest mortality was observed in the 2nd deciles (22.09%) and the 8th to 10th deciles (22%, 27.15% and 28.38% respectively). Hazard function of prolonged QTc Conclusion(s) 1. In this worker cohort from Thailand, prolonged QTc was observed in 14% of the population. 2. During 18 years follow up, prolongation of QT interval is an independent risk factor for all-cause mortalities but not cardiovascular mortality. 3. There was a J-curve effect in association between the duration of QT interval and all-cause mortality.

QTc interval prolongation in asymptomatic HIV – infected patients treated and untreated with antiretroviral therapy

Aim: QTc interval prolongation has been found in HIV-infected patients. There are contradictory reports about the effects of antiretroviral drugs on QT interval duration. The aim of the study was to assess if the prolongation of the QTc interval depends on the antiretroviral treatment and other risk factors related to HIV infection. Material/Methods: 283 adult HIV-infected patients treated in HIV Outpatient Clinic in Warsaw were enrolled in the prospective, single-centre study. Factors related to ART and HIV infection were collected. Electrocardiograms were performed for each patient and QTc interval duration was measured and corrected using Bazett’s heart rate formula. Results: Prolonged QTc interval was identified in 4.9 % HIV-infected patients (median age 34.5 years, 85% male, 89% HIV RNA&lt;50 copies/mL). The average length of QTc interval in ART HIV(+) patients was 403 ms, in untreated HIV(+) subjects – 398ms and in the control group of healthy individuals – 400ms. ART regimen included PI in 47.4% cases, NNRTI in 24.1% and INI in 28.5% patients. The longest QTc interval was found in patients treated with the PI scheme – 408 ms, shorter with INI – 399ms and with NNRTI – 397ms. A multivariable analysis revealed that only older age and female gender were significantly associated with QTc prolongation. Conclusions: In the group of young, asymptomatic HIV-infected patients with good immunovirological control, the prevalence of QTc prolongation was low – only 4.9% of subjects. ARV treatment seem to have no significant influence on the QTc interval duration.

QTc Prolongation Associated With Psychiatric Medications: A Retrospective Cross-Sectional Study of Adult Inpatients.

The aim of our study was to assess the impact of psychiatric medications and concomitant risk factors on the prevalence of QTc prolongation and torsades de pointes (TdP) in hospitalized subjects. We examined the association between individual risk scores and QTc prolongation and proposed an evidence-based protocol for electrocardiogram monitoring on psychotropic medications. Electrocardiograms (ECGs) of subjects hospitalized over a 1-year period were analyzed for QTc prolongation, associated risk factors, and use of medications. Analysis was performed using logistic regression to identify independent predictors of QTc prolongation, and the Pearson χ test was used for risk score assessment. A total of 1249 ECGs of 517 subjects were included in this study. Eighty-seven subjects had QTcB intervals greater than 470 milliseconds for females and greater than 450 milliseconds for males. Twelve (2.3%) subjects had QTcB of 500 milliseconds or greater, or greater than 60 milliseconds of change from baseline. Of these subjects, only 1 case of QTc interval change was related to routine use of psychiatric medications. There were no incidents of TdP. Age, diabetes, hypokalemia, overdose, diphenhydramine, and haloperidol were significant independent predictors of QTc prolongation. Risk scores were significantly correlated with QTc prolongation (P = 0.001). Our retrospective review study found that the occurrence of TdP and QTc prolongation was low in this subject population. QT abnormalities were associated with known risk factors, and risk scores correlated well with QTc prolongation. Providers can use the protocol proposed in this study, which incorporates risk scores and the CredibleMeds classification system to determine the need for ECG monitoring and to guide treatment.

Effect of serum electrolytes within normal ranges on QTc prolongation: a cross-sectional study in a Chinese rural general population

BackgroundMany previous clinical studies have reported that prolongation of the QT interval corrected for heart rate (QTc) is associated with an increased risk of sudden cardiac death and all-cause mortality. This study aimed to explore associations between serum electrolytes and QTc prolongation in the north-eastern Chinese rural general population.MethodsWe performed a cross-sectional study including 10,334 (4820 men and 5514 women) from the general population aged ≥35 years in the Liaoning Province from 2012 to 2013. Anthropometric measurements, laboratory examinations and self-reported lifestyle factor information, echocardiography and electrocardiogram were collected by trained personnel. The associations between serum electrolytes and QTc prolongation were tested using multiple linear regression and logistic regression analyses.ResultsThe mean QTc interval were 415.6 ± 18.8 and 470.1 ± 23.1 ms in normal group and QTc prolongation group respectively. The prevalence of QTc prolongation increased significantly with a decrease in serum potassium and an increase in magnesium. Stepwise multiple linear regression showed that age, hypertension, waist circumference were prominently positive associated with QTc interval both in male and female population. But serum potassium was significantly inversely associated with QTc interval. Serum magnesium and calcium also showed a positive relationship with QTc interval. Furthermore, multiple logistic regression found that lower quartile of serum potassium had higher risk for QTc prolongation, especially in female population (Q2 vs. Q4: OR: 1.54, 95%CI: 1.01–2.35; Q1 vs. Q4: OR: 2.02, 95%CI: 1.36–3.01). In addition, the higher serum magnesium increased the risk of QTc prolongation, which was significantly only in male population.ConclusionsIn present Chinese rural general population, even with normal range, a decrease in serum potassium and an increase in serum magnesium are important risk factors for QTc prolongation.