Prevalence Of QT Interval Prolongation Research Articles

Predictors for prolonged qt intervals in acute antipsychotic poisoned patients.

Acute antipsychotic poisoning is correlated to a high prevalence of qt interval prolongation. This study aimed to evaluate early qt interval prolongation predictors in acute antipsychotic-poisoned patients. This prospective cohort study enrolled 70 symptomatic patients with acute antipsychotic poisoning. Sociodemographic data, toxicological, clinical, investigation, and outcomes were collected and analyzed. The estimation of the corrected qt interval (QTc) was performed using Bazett's method. Primary outcome was normal or abnormal length of QTc interval. Secondary outcomes included duration of hospital stay, complete recovery and mortality. The corrected qt interval was analyzed by univariate and multivariate logistic regression analysis. Patients were divided into groups A (normal QTc interval up to 440msec; 58.6% of cases) and B (prolonged QTc interval≥440msec; 41.4% of cases). Patients in group B had significantly high incidences of quetiapine intake, bradycardia, hypotension, hypokalemia, and long duration of hospital stay. By multivariate analysis, quetiapine [Odd's ratio (OR): 39.674; Confidence Interval (C.I:3.426-459.476)], bradycardia [OR: 22.664; C.I (2.534-202.690)], and hypotension [OR: 16.263; (C.I: 2.168-122.009)] were significantly correlated with prolonged QTc interval. In acute antipsychotic poisoning, quetiapine, bradycardia, and hypotension are early clinical predictors for prolonged QTc interval.

Association Between Disturbed Serum Phosphorus Levels and QT Interval Prolongation

INTRODUCTIONQT interval prolongation is a risk factor for fatal arrhythmias and other cardiovascular complications. QT interval prolongation in hemodialysis (HD) patients is not well understood. Hypocalcemia is a suspected, but poorly verified etiology in these patients, and the association between serum phosphorus levels and QT interval prolongation is unknown. We sought to determine the prevalence of QT interval prolongation in HD patients and to verify the association between pre-dialysis serum Ca and P levels and QT interval prolongation. METHODSA cross-sectional study was conducted on adult maintenance HD patients enrolled in the Japanese Society for Dialysis Therapy and Renal Data Registry 2019. After assessing patient characteristics, linear regression analysis was performed with pre-dialysis serum Ca and P levels as exposures and a rate-corrected QT (QTc) interval as the outcome. RESULTSA total of 204,530 patients were analyzed with a mean QTc of 451.2 msec (SD = 36.9 msec). On multivariable analysis, estimated change in QTc (coefficients, [95% confidence interval {CI}])] per 1 mg/dL increase in serum Ca and P was -2.02 [-3.00, -1.04] and 5.50 [3.92,7.09], respectively. In the restricted cubic spline curve, estimated change in QTc increased with lower values of serum Ca. The correlation between serum P and QTc showed a U-shaped curve. CONCLUSIONDecreased serum Ca levels and decreased and increased serum P levels may be associated with QT interval prolongation in maintenance HD patients.

Serial electrocardiogram recordings revealed a high prevalence of QT interval prolongation in patients with tuberculosis receiving fluoroquinolones

Fluoroquinolones, crucial components of treatment regimens for drug-resistant tuberculosis (TB), are associated with QT interval prolongation and risks of fatal cardiac arrhythmias. However, few studies have explored dynamic changes in the QT interval in patients receiving QT-prolonging agents. This prospective cohort study recruited hospitalized patients with TB who received fluoroquinolones. The study investigated the variability of the QT interval by using serial electrocardiograms (ECGs) recorded four times daily. This study analyzed the accuracy of intermittent and single-lead ECG monitoring in detecting QT interval prolongation. This study included 32 patients. The mean age was 68.6±13.2 years. The results revealed mild-to-moderate and severe QT interval prolongation in 13 (41%) and 5 (16%) patients, respectively. The incremental yields in sensitivity of one to four daily ECG recordings were 61.0%, 26.1%, 5.6%, and 7.3% in detecting mild-to-moderate QT interval prolongation, and 66.7%, 20.0%, 6.7%, and 6.7% in detecting severe QT interval prolongation. The sensitivity levels of lead II and V5 ECGs in detecting mild-to-moderate and severe QT interval prolongation exceeded 80%, and their specificity levels exceeded 95%. This study revealed a high prevalence of QT interval prolongation in older patients with TB who receive fluoroquinolones, particularly those with multiple cardiovascular risk factors. Sparsely intermittent ECG monitoring, the prevailing strategy in active drug safety monitoring programs, is inadequate owing to multifactorial and circadian QT interval variability. Additional studies performing serial ECG monitoring are warranted to enhance the understanding of dynamic QT interval changes in patients receiving QT-prolonging anti-TB agents.

Prevalence of QTc interval prolongation and its associated risk factors among psychiatric patients: a prospective observational study

BackgroundQT interval prolongation is a growing concern worldwide, posing psychiatric patients to life-threatening fatal arrhythmias i.e., torsade de pointes. This study aimed to identify the prevalence of QT interval prolongation, its associated risk factors and prescribing patterns of QT prolonging drugs among psychiatric patients.MethodA prospective observational study was conducted that included psychiatric patients from a tertiary care hospital and a psychiatry clinic in Peshawar, Khyber Pakhtunkhwa, Pakistan. Electrocardiogram was recorded of those patients who were using psychotropic medications for ≥7 days, aged 18 years or more, and of either gender, male or female. The Fredericia correction formula was used for measuring QTc values (corrected QT). Chi-square test was applied to estimate differences between patients with or without prolonged QTc interval whereas, logistic regression analysis was performed to identify various predictors of QT interval prolongation.ResultsOut of 405 patients, the QTc interval was prolonged in 23 (5.7%) patients including 1 (0.2%) patient with highly abnormal prolonged QTc interval (> 500 ms). QT drugs (91.6%), female sex (38.7%) and hypertension (10.6%) were the most common QT prolonging risk factors. Prolonged QTc interval was significantly higher among male patients (p = 0.007).ConclusionIn the present study, QT interval prolongation was observed in a considerable number of psychiatric patients. While, the high prevalence of QT prolonging risk factors among these patients warrants the increased risk of fatal arrhythmias. Therefore, risk assessment and electrocardiographic monitoring, and prescription of safer alternatives are highly recommended.

QT interval prolongation in hospitalized patients on cardiology wards: a prospective observational study.

Prolonged QT interval may lead to a lethal form of arrhythmia, torsades de pointes (TdP), which is associated with cardiovascular mortality. Therefore, we aimed to identify prevalence of QT interval prolongation, compare clinical characteristics of patients with normal and prolonged QT interval, and identify predictors of QT interval prolongation. A prospective observational study was conducted in cardiology wards of two teaching hospitals in Pakistan. Bazett's correction formula was used for the calculation of QTc interval. Prevalence of QT prolongation and pro-QTc scores were calculated. Comparative analysis was performed with respect to various clinical characteristics by applying t test and chi-square test. Odds ratios were calculated using regression analysis. Among 417 patients, 44.6% were found having prolonged QT interval, of which, 17.3% presented with an abnormally high QTc interval (> 500ms). Significant difference was recorded between the groups (normal vs. prolonged) with respect to age, all prescribed medications, QT drugs, number of risk factors, QT-DDIs (QT-prolonging drug-drug interactions), gender, and diuretics use. Multivariate logistic regression analysis showed significant results for various predictors such as male gender (p=0.03), various age categories 41-50years (p=0.04), 51-60years (p=0.01), and > 60years (p<0.001), and diuretics (p=0.008). A substantial number of patients in cardiology wards presented with QT prolongation. Proper considerations are needed in order to minimize the associated risk particularly in patients with abnormally high QT prolongation, old age, polypharmacy, one or more QT-prolonging drugs, and high pro-QTc scores.

Prolongation of the QTc interval in HIV-infected individuals compared to the general population.

Prolonged QT interval is associated with arrhythmias and sudden death. An increased prevalence of QT interval prolongation in human immunodeficiency virus-infected (HIV) subjects was previously described. The impact of different medications and HIV infection itself on the QT interval is rarely investigated in large HIV+ cohorts. We compared QT interval measurement in 496 HIV(+) patients of the HIV-HEART study (HIVH) and 992 sex- and age-matched controls of the population-based German Heinz Nixdorf Recall study (HNR). QT corrected for heart rate (QTc) >440ms in male and >460ms in female was considered pathological. We analysed the impact of HIV status and HIV medication on QTc prolongation in the HIVH subjects. We observed longer QTc in HIVH subjects compared with HNR controls: 424.1ms±23.3 vs. 411.3±15.3ms for male and 435.5ms±19.6 vs. 416.4ms±17.3 for female subjects (p<0.0001 for both sexes). Adjusting for QT prolonging medication the mean differences in QTc between the two studies remained significant with 12.6ms (95% CI 10.5-14.8; p value <0.0001) for male and 19.3ms (95% CI 14.5-24.2; p value <0.0001) for female subjects. Prolongation of QTc was pathologic in 22.8 vs. 3.9% of HIV(+) and non-infected males and in 12.1 vs. 1.8% of the females [OR of 7.9 (5.0-12.6) and OR of 6.7 (1.8-24.2), respectively]. Smoking behaviour was an independent factor to lengthen QTc in HIV(+) patients. Diabetes mellitus was not a risk factor itself, but might be associated with medication which was associated with LQT. We could not observe any influence of the HIV status, ART, or any co-medication on the QTc. Our study showed that HIV(+) patients had significantly longer QTc intervals compared to the general population. The number of patients with pathologic QTc prolongation was significantly increased in HIV(+) population.

Prevalence of QT interval prolongation in inflammatory bowel disease.

There is growing evidence linking various cardiac complications with inflammatory bowel disease (IBD). Electrolyte abnormalities, chronic inflammation, and medication use (such as Infliximab) that are associated with IBD are all independent risk factors for QT interval prolongation. Given that malignant ventricular arrhythmias are associated with QT interval prolongation, it is important to risk stratify this subset of patients. Our objective was to evaluate the prevalence of abnormal QT interval prolongation (defined by a QT interval of >450 ms in men and >460 ms in women) in an IBD population. A retrospective chart review of patients with IBD from the Metro Hospital database was performed. Patients' demographic characteristics and laboratory data were abstracted. "RR" and "QT" intervals were measured from the last available electrocardiogram, and corrected QT (QTc) interval was calculated from lead II using Bazett's formula. Of 142 eligible patients, 42.3% (n=22/52) of males and 48.9% (n=44/90) of females had a prolonged QTc interval. Patients with IBD having a prolonged QTc interval had a higher body mass index than those with a normal QTc interval (29.7±6.9 vs. 26.2±5.9, p=0.005). Our study demonstrates that patients with IBD are at a higher risk of developing QTc interval prolongation.

Prevalence of QT Interval Prolongation in Patients Admitted to Cardiac Care Units and Frequency of Subsequent Administration of QT Interval-Prolonging Drugs

Cardiac arrest due to torsades de pointes (TdP) is a rare but catastrophic event in hospitals. Patients admitted to cardiac units are at higher risk of drug-induced QT interval prolongation and TdP, due to a preponderance of risk factors. Few data exist regarding the prevalence of QT interval prolongation in patients admitted to cardiac units or the frequency of administering QT interval-prolonging drugs to patients presenting with QT interval prolongation. The aim of this study was to determine the prevalence of Bazett's-corrected QT (QT(c)) interval prolongation upon admission to cardiac units and the proportion of patients presenting with QT(c) interval prolongation who are subsequently administered QT interval-prolonging drugs during hospitalization. This was a prospective, observational study conducted over a 1-year period (October 2008-October 2009) in 1159 consecutive patients admitted to two cardiac units in a large urban academic medical centre located in Indianapolis, IN, USA. Patients were enrolled into the study at the time of admission to the hospital and were followed daily during hospitalization. Exclusion criteria were age <18 years, ECG rhythm of complete ventricular pacing, and patient designation as 'outpatient' in a bed and/or duration of stay <24 hours. Data collected included demographic information, past medical history, daily progress notes, medication administration records, laboratory data, ECGs, telemetry monitoring strips and diagnostic reports. All patients underwent continuous cardiac telemetry monitoring and/or had a baseline 12-lead ECG obtained within 4 hours of admission. QT intervals were determined manually from lead II of 12-lead ECGs or from continuous lead II telemetry monitoring strips. QT(c) interval prolongation was defined as ≥470 ms for males and ≥480 ms for females. In both males and females, QT(c) interval >500 ms was considered abnormally high. A medication was classified as QT interval-prolonging if there were published data indicating that the drug causes QT interval prolongation and/or TdP. Study endpoints were (i) prevalence of QT(c) interval prolongation upon admission to the Cardiac Medical Critical Care Unit (CMCCU) or an Advanced Heart Care Unit (AHCU); (ii) proportion of patients admitted to the CMCCU/AHCU with QT(c) interval prolongation who subsequently were administered QT interval-prolonging drugs during hospitalization; (iii) the proportion of these higher-risk patients in whom TdP risk factor monitoring was performed; (iv) proportion of patients with QT(c) interval prolongation who subsequently received QT-prolonging drugs and who experienced further QT(c) interval prolongation. Of 1159 patients enrolled, 259 patients met exclusion criteria, resulting in a final sample size of 900 patients. mean (± SD) age, 65 ± 15 years; female, 47%; Caucasian, 70%. Admitting diagnoses: heart failure (22%), myocardial infarction (16%), atrial fibrillation (9%), sudden cardiac arrest (3%). QT(c) interval prolongation was present in 27.9% of patients on admission; 18.2% had QT(c) interval >500 ms. Of 251 patients admitted with QT(c) interval prolongation, 87 (34.7%) were subsequently administered QT interval-prolonging drugs. Of 166 patients admitted with QT(c) interval >500 ms, 70 (42.2%) were subsequently administered QT interval-prolonging drugs; additional QT(c) interval prolongation ≥60 ms occurred in 57.1% of these patients. QT(c) interval prolongation is common among patients admitted to cardiac units. QT interval-prolonging drugs are commonly prescribed to patients presenting with QT(c) interval prolongation.

QT interval prolongation in patients with hypertensive heart disease

Background: The study assessed the prevalence of QT interval prolongation and identified its associated factorsMethods: The study was cross-sectional in design. Subjects confirmed on echocardiography to have HHD were recruited consecutively from 3 echocardiography laboratories in the Kano City, Nigeria, over 7 months. Prolonged QTc was defined as QTc > 440 ms in males and > 460 ms in females, or more than 500ms in both sexes in the presence of complete bundle branch block. A p-value of

The relation between QTc interval prolongation and diabetic complications. The EURODIAB IDDM Complication Study Group.

The prevalence of QT interval prolongation is higher in people with diabetes and its complications. Sudden death has been reported as a common cause of death in insulin-dependent diabetic patients affected by autonomic neuropathy. It has been postulated that QT prolongation predisposes to cardiac arrhythmias and sudden death. In this analysis the prevalence of QT interval prolongation and its relation with diabetic complications were evaluated in the EURODIAB IDDM Complications Study (3250 insulin-dependent diabetic patients attending 31 centres in 16 European countries). Five consecutive RR and QT intervals were measured with a ruler on the V5 lead of the resting ECG tracing and the QT interval corrected for the previous cardiac cycle length was calculated according to the Bazett's formula. The prevalence of an abnormally prolonged corrected QT was 16% in the whole population, 11% in males and 21 % in females (p < 0.001). The mean corrected QT was 0.412 s in males and 0.422 s in females (p < 0.001). Corrected QT duration was independently associated with age, HbA1c and blood pressure. Corrected QT was also correlated with ischaemic heart disease and nephropathy but this relation appeared to be stronger in males than in females. Male patients with neuropathy or impaired heart rate variability or both showed a higher mean adjusted corrected QT compared with male patients without this complication. The relation between corrected QT prolongation and autonomic neuropathy was not observed among females. In conclusion we have shown that corrected QT in insulin-dependent diabetic female patients is longer than in male patients, even in the absence of diabetic complications known to increase the risk of corrected QT prolongation.

QT interval changes following neck dissection. A stratified prospective study.

Studies from Europe have suggested that neck dissection, especially right radical neck dissection, causes a dangerous prolongation of the QT interval. Sudden cardiac arrest due to QT prolongation has been reported following right radical neck dissection. We investigated the prevalence of QT interval prolongation following neck dissection. Electrocardiogram tracings from 45 patients who underwent different combinations of neck dissection were studied. Preoperative and postoperative tracings were interpreted by a cardiologist blinded to the patient identification of each tracing. There were 28 unilateral neck dissection patients and 17 bilateral neck dissection patients eligible for analysis. There were 7 patients in the classic right radical neck dissection group, and only 3 of these had no neck dissection on the left. Comparisons of preoperative versus postoperative corrected QT interval for all subjects did not indicate a significant change. Stratification by neck dissection type (radical, modified or selective, and carotid artery resection) or by side dissected (left, right, or both) also showed no significant differences. No malignant arrhythmias were encountered. Thus, in contrast to the European experience, our findings show no significant predictable change in the QT interval after any of the combinations of neck dissection. Head and neck surgeons should be aware of the possibility of postoperative QT interval prolongation following neck dissection, although in the absence of other risk factors it appears to be a rare occurrence.