Association between metabolic syndrome with QTc interval prolongation in physical examination subjects / 重庆医学

Objective To explore the relationship between metabolic syndrome(MS) and corrected QT(QTc) interval prolongation.Methods A total of 1 260 participants having electrocardiogram examinations,aged over 18 years old from June 2015 to June 2016 were included and divided into the MS group and non-MS group.QTc was calculated according to the Bazett formula.The Logistic regression model was established for exploring the association between MS and QTc.Results There were 63 cases of QTc interval prolongation in the MS group,however,40 cases in the non-MS group(P＜0.01).In the unadjusted model,MS was a risk factor of QTc interval prolongation[OR =6.36,95 ％ CI(2.34,8.67),P＜ 0.01].After further adjusting confounders,MS was still correlated with QTc interval prolongation[OR =4.11,95 ％ CI(2.09,7.13,P＜ 0.01].In the study of the relationship between the MS groups with QTc interval prolongation,after adjusting confoundingfactors,only abdominal obesity[OR=2.76,95％ CI(1.43,7.56),P＜0.01] and hypertriglyceridemia[OR=1.75,95％CI(1.22,4.31),P=0.013)] were closely correlated with QTc interval prolongation.Conclusion MS is an independent risk factor of QTc interval prolongation.It is especially important to strengthen the management of blood lipid and abdominal circumference.

Electrocardiographic corrected QT interval prolongation and its risk factors in patients with clozapine treatment / 中国神经精神疾病杂志

Objective To investigate risk factors of corrected QT (QTc) interval prolongation in schizophrenia pa-tients treated with clozapine. Methods Two hundred and ten schizophrenia patients treated with clozapine were included in the study. Measurement of myocardial enzymes and electrocardiography were performed to determine QTc interval. QTc interval was calculated according to Bazett’s formula. Results QTc prolongation prevalence rate was 15.24%, The QTc prolongation prevalence rate was higher in female than in male (29.23%vs. 8.98%, P0.05). Multi-factors linear regression analysis showed that heart rate was related with QTc interval (β=0.719, standardizedβ=0.691, P=0.027). Conclusions QTc interval prolonga-tion prevalence rate is high in patients treated with clozapine. And increased heart rate might be risk factor of QTc inter-val prolongation.

An Association Between the Prolonged Heart Rate-corrected QT Interval and Global Functional Outcome in Patients with Subarachnoid Hemorrhage

PURPOSE: Autonomic dysfunctions after subarachnoid hemorrhage (SAH) may lead to various arrhythmias, electrocardiographic abnormalities, and myocardial dysfunction. Prolongation of the heart rate-corrected QT (QTc) interval is frequently observed in patients with SAH. The aim of this study was to examine the associations between the QTc interval and global functional outcome in patients with SAH. METHODS: We studied 413 adult patients admitted via the emergency department within 48 hours after the onset of spontaneous SAH from January 2007 to December 2011. Among 413 patients with SAH, there were 154 male and 258 female patients whose mean age was 58.8+/-12.4 years. QT intervals were measured by standard 12-lead electrocardiography (ECG) and corrected by Bazett formulae. The QTc interval were considered prolonged at >450 ms in men and >470 ms in women. Outcomes were assessed using the length of hospital stay and the Modified Rankin scale (MRS) at discharge. RESULTS: One or more repolarization abnormalities occurred in 61.9% of patients. The most frequently observed ECG abnormality was QTc prolongation (54.9%), followed by non-specific ST-T changes(16.2%), ST-depression(9.2%), T-wave inversion(11.4%), U-wave(2.7%), and ST-segment elevation(1.7%). No correlations were found between age, sex, body mass index (BMI), location of aneurysm, and QTc interval. Multiple logistic regression analysis showed a relationship between prolonged QTc and Hunt Hess grades (p=0.012) in men, length of hospital stay (p=0.038) in women, Fisher grade (p=0.001), and MRS (p=0.006, p=0.011) in both. CONCLUSION: The prolonged QTc interval is more frequently observed in patients with severe hemorrhage and an unfavorable functional outcome (MRS 4-6) in SAH patients.

A Case of QTc Interval Prolongation Associated With Quetiapine / 대한정신약물학회지

The QT interval is a measure of the time between the start of the Q wave and the end of the T wave in the cardiac electrical conduction and has to be corrected for heart rate, namely, QTc. QTc interval prolongation can occur as a result of treatment with both conventional and novel antipsychotic medications; it is of clinical concern because it is associated with a potentially fatal ventricular arrhythmia, torsade de pointes. A 33-year-old female patient with schizophrenia developed a prolonged QTc interval while taking quetiapine. Her QTc returned to baseline levels when quetiapine was discontinued. The quetiapine-related QTc prolongation might have been associated with the use of a high dose quetiapine with rapid titration or prior use of ziprasidone, which is metabolized by the same cytochrome P450 enzyme that metabolizes quetiapine. The results suggest that it is important for physicians to identify pretreatment cardiac conduction abnormalities and other risk factors associated with QTc interval prolongation when prescribing quetiapine, especially high dosages or during the concomitant use of other P450 3A4 inhibitors. It is also important to check a baseline ECG before starting treatment.