• Clinical and Experimental Pediatrics
• /
• v.58 no.7
• /
• pp.263-266
• /
• 2015

Purpose: Ventricular repolarization is assessed using the QT interval corrected by the heart rate (QTc) via an electrocardiogram (ECG). Prolonged QTc is associated with an increased risk of arrhythmias and cardiac mortality. As there have been few reports regarding the effects of hyperthyroidism on ventricular repolarization, we studied the association between serum free thyroxine (free T4 [fT4]) and thyroid stimulating hormone (TSH) levels and the QTc interval. Methods: Thirty-eight patients with hyperthyroidism (<30 years old) were included, and we used their clinical records and available ECGs (between August 2003 and August 2011) to evaluate the association between their fT4 and TSH levels and their QTc interval. In addition, we studied the ECGs of 72 age-matched patients with no hyperthyroidism (control group) and compared their data with that from the patients group. Results: The QTc duration in patients with hyperthyroidism was significantly prolonged compared to that in the control subjects (P<0.001). In addition, the number of hyperthyroid patients with abnormal prolonged QTc was significantly higher than that in the control group (P<0.001). Among the patients with hyperthyroidism, patients with prolonged QTc and borderline QTc had higher fT4 levels and there was positive correlation between their fT4 levels and their QTc interval (P<0.05). However, no correlation was observed between their TSH levels and their QTc interval. Conclusion: We report that hyperthyroidism is associated with QTc prolongation. The correlation between the fT4 levels and the QTc interval suggests that thyroid status is associated with QTc values and the risk of cardiac mortality.

• Korean Journal of Psychosomatic Medicine
• /
• v.29 no.1
• /
• pp.11-16
• /
• 2021

Objectives : QTc prolongation due to antipsychotics is of major concern because it may lead to fatal ventricular arrhythmia such as torsade de pointes. However, few studies have been conducted on QTc prolongation due to antipsychotics, especially in South Korea. This study aimed to investigate how demographic and clinical variables affect QTc interval in patients with schizophrenia. Methods : By retrospectively reviewing medical records, we assessed QTc interval, demographic data and clinical features of 441 (175 males) patients with schizophrenia who admitted to the psychiatric ward of a general hospital. To explore the predictive factors for QTc interval, hierarchical regression analysis was performed with QTc interval as the dependent variable. Results : The mean QTc interval was 417.2±28.4 ms. In the hierarchical regression analysis, the use of short-acting antipsychotic injection was the strongest predictor of the QTc prolongation. Conclusions : This study demonstrated that the use of short-acting antipsychotic injection may affect QTc prolongation in patients with schizophrenia. This result suggests that more attention should be paid to the use of short-acting antipsychotic injection in the treatment of schizophrenia.

• Journal of Preventive Medicine and Public Health
• /
• v.39 no.6
• /
• pp.455-461
• /
• 2006

Objectives : Prolongation of the heart rate-corrected QT (QTc) interval has been reported to be associated with cardiovascular morbidity and mortality. However, few studies have examined the relationship between the QTc interval and cardiovascular risk factors in young healthy people, The aim of this study was to examine the associations between the QTc interval and cardiovascular risk factors in young healthy adults. Methods : This study was performed as part of the Kangwha study, which started in 1986, and is an on-going follow-up study on blood pressure and related cardiovascular risk factors. In follow-up examinations during 2005, cardiovascular risk factors, including anthropometrics, blood pressure, blood chemistry and carotid ultrasonography, were measured, and questionnaires on health behaviors completed by 127 men and 149 women aged 25 years. The QTc interval was measured on the resting 12-lead electrocardiogram using an automatic analysis program. Results : The mean QTc interval was significantly longer in women $(419{\pm}17ms)$ than in men $(405{\pm}17ms)$ (p<0.001). A significant positive correlation was found between the QTc interval and waist-hip ratio (p=0.030) in men. Women showed a positive correlation between the QTc interval and systolic blood pressure (p=0.017). On a multiple regression analysis, the QTc interval was positively associated with the waist-hip ratio in men (p=0.012) and with the systolic blood pressure (p=0.020) in women. Conclusions : In young healthy Korean adults, the QTc interval was independently associated with the waist-hip ratio in men and with the systolic blood pressure in women.

• Journal of Life Science
• /
• v.19 no.1
• /
• pp.81-86
• /
• 2009

The purpose of the present study was to examine effect of 12 week regular aerobic exercise on ST-segment and QTc interval in middle age type 2 diabetes mellitus (T2DM) patients. The subjects consist of 13 type 2 diabetes mellitus (T2DM) patients in middle age men and all of them had no other complications. Subjects participated in aerobic exercise training for 12 weeks. They started to exercise for $20{\sim}60$ min at $60{\sim}80%$ of $HR_{max}$, (exercise intensity has been increased gradually) per day, $3{\sim}5$ times a week. The results were compared before and after. Weight and BMI, % body fat, fasting glucose, HOMA-IR, $_{peak}DBP$ were significantly decreased and $_{peak}HR$, $_{peak}VO_2$, exercisre time were significantly increased after 12 week aerobic exercise. Also, QTc interval and ST-segment were significantly decreased during at rest, peak exercise after 12 week aerobic exercise. Conclusionally, 12 week aerobic exercise may be improvement in decreased cardiovascular mortality factors (ST-segment) and abnormal autonomic dysfunction (QTc interval) and potentially increased exercise capacity.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.18 no.2
• /
• pp.130-135
• /
• 2020

Purpose: Taking large amounts of glyphosate is life-threatening, but the amounts of glyphosate taken by patients for suicide are not known precisely. The purpose of this study was to find the predictors of large amounts of glyphosate ingestion. Methods: This retrospective study analyzed patients presenting to an emergency department with glyphosate intoxication between 2010 and 2019, in a single tertiary hospital. The variables associated with the intake amounts were investigated. The parameters were analyzed by multivariate variate logistic regression analyses and the receiver operating characteristic (ROC) curve. Results: Of the 28 patients with glyphosate intoxication, 15 (53.6%) were in the large amounts group. Univariate analysis showed that metabolic acidosis, lactic acid, and corrected QT (QTc) interval were significant factors. In contrast, multivariate analysis presented the QTc interval as the only independent factor with intoxication from large amounts of glyphosate. (odds ratio, 95% confidence interval: 1.073, 1.011-1.139; p=0.020) The area under the ROC curve of the QTc interval was 0.838. Conclusion: The QTc interval is associated significantly with patients who visit the emergency department after being intoxicated by large amounts of glyphosate. These conclusions will help in the initial triage of patients with glyphosate intoxication.

• Proceedings of the KAIS Fall Conference
• /
• 2009.05a
• /
• pp.222-226
• /
• 2009

본 연구는 40~50대 중년여성을 대상으로 측정한 체내지방분포와 심전도 QTc 간격과의 관련성을 규명하기 위하여 2004년 7월부터 2005년 8월까지 일개 광역도 소재의 일개 군 보건소 운동처방실을 방문한 여자 100명을 대상으로 체내지방분포와 심전도 QTc 간격 등을 측정하였다. 주요 결과는 다음과 같다. 1. 중년여성의 안정시 심전도 QTc 간격과 체내지방분포와의 상관관계에서는 비만도, 체질량지수, 체지방율, 허리둘레, 엉덩이둘레, 허리-엉덩이둘레 비가 유의한 상관관계를 보였다. 2. 체지방율이 30% 이상인 비만군과 30% 미만인 정상군의 QTc 간격은 비만군이 정상군에 비해 QTc 간격이 더 연장된 결과를 보였다. 3. 허리둘레가 80cm 이상인 복부비만군과 80cm 미만인 정상군의 QTc 간격은 복부비만군이 정상군에 비해 QTc 간격이 더 연장된 결과를 보였다. 4. 연구대상자의 안정시 QTc 간격을 종속변수로 한 다중회귀분석을 실시한 결과를 살펴보면, 체지방율과 허리둘레가 유의하게 나타났다. 40~50대 중년여성의 심전도 QTc 간격에 영향을 주는 요인에는 체내지방분포에 따른 비만도, 체질량지수, 체지방율, 허리둘레, 엉덩이둘레 등 여러 요인들이 복합적으로 관련되는 것으로 판단되어지며, 그 중 전체지방분포를 나타내는 체지방율이 가장 크게 관련되는 것으로 판단되어진다.

• Journal of Yeungnam Medical Science
• /
• v.8 no.2
• /
• pp.52-62
• /
• 1991

The toxic effect of azalea extract, expecially on cardiovascular system, is relatively unclear. The purpose of this study is to study the possible underlying mechanism and effect of toxic ingredient of azalea on cardiovascular system. The 71 healthy rabbits were divided into 10 groups : In group as preliminary study ; 4cc of normal saline was administered intravenously(N) ; 0.7gm/kg and 1.0gm/kg of azalea extract was administered respectively in the same route, volume(A1, A2) ; atropine was administered intravenously(A) ; after pretreatment with atropine(0.04mg/kg) to block parasympathetic system, azalea extract was injected like the above groups(AA1, AA2) ; normal saline, 0.7gm/kg and 1.0gm/kg of azalea extract were administered respectively with 0.2cc(1 : 1000) epinephrine(E0,E1,E2). We measured the following indices at I minute interval during first 10 minutes and then 10 minute interval during next 30 minutes : RR interval, QTc interval, maximal systolic and diastolic pressure drop with occuring time and presence of significant arrhythmia. The results were as follows : 1. The changes of RR interval, QTc interval were significantly increased in groups by Azalea extract. The blood pressure change was significantly decreased in groups by Azalea extract. There were no significant differences according to dosage of Azalea extract. 2. The changes of RR interval, blood pressure were significant differences between administration of atropine and Azalea extract after pretreatment with atropine, but not in the change of QTc interval. 3. There were no significant differences in the change of RR interval, ATc interval, blood pressure drop according to pretreatment with atropine. 4. The interaction between epineprine and Azalea extract was not noted by the effect of epineprine itself. 5. The ST change by 0.7gm/kg, 1.0gm/kg of Azalea extract was revealed in 1 case(14.0%), 7 case(100%), respectively. 6. Most of all cases with arrhthymia, ventricular tachycardia, ventricular fibrillation, were noted in the group by epineprine, except one case by Azalea extract(1.0gm/kg). It was idioventricular rhythm. In conclusion, azalea extract has negative inotropic and chronotropic effect with arrhythmogenic potential possibly through direct myocardial ischemia or injury but we cann't be absolutely exclusive of actions of autonmic nervous system, especially parasympathetic nervous system.

• Proceedings of the KOSOMBE Conference
• /
• v.1989 no.05
• /
• pp.13-14
• /
• 1989

Prolongation in QT corrected interval (QTc), measured in surface ECG, has been shown in the majority af patients to be marker of bad prognosis in postmyocardial infarction patients (PMIP). Hence it would seem logical that dynamic QTc interval measurement can be a very usefull indicator to stratify prognosis in PMIP. We present a new algorithm for QT as well as for QTP (distance value from Q wave onset to T wave peak) intervals measurement in 24 hour ECG Holter tapes. Validation of the algorithm by hand measurement has been done on first beats of 18 Holter tapes, resulting in a magnitude of deviations between 10 and 15 ms. Application on 24 hour Holter ECG signal has also been done.

• Korean Journal of Veterinary Research
• /
• v.52 no.3
• /
• pp.163-167
• /
• 2012

Mosapride stimulated dietary motility was introduced because of the arrhythmogenic effect of cisapride. Cisapride, 5-HT receptor agonist, induces prolongation of QT interval. Additionally, this condition can raise the possibility of acute, "malignant" arrhythmias such as torsade de pointes. It is hard to find any reports about effects of mosapride on cardiac parameters in dogs. By confirming electrocardiogram (ECG) parameters, the surface extremity leads ECG that was obtained from the four-limb electrodes and which was recorded by an ECG recorder after administration of mosapride 3 mg/kg PO b.i.d, and mosapride 3 mg/kg with itraconazole 5 mg/kg PO b.i.d, respectively. QT interval was shortened on the days of 3, 5, and post-day 1 in both mosapride 3 mg/kg administrated group and mosapride with itraconazole group. Heart rate increased significantly. QTc was slightly prolonged in mosapride administration group and mosapride with itraconazole group. However, all dogs of QTc were in normal variation (150~250 msec). Besides, the dogs showed no side effects reported in human medicine during the administration with these drugs. Although mosapride can increase the heart rate, this study suggest that mosapride may be useful for the dogs with disorders of gastrointestinal motility because of no fatal arrhythmogenic effect inspite of administration with itraconazole in dogs.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.7 no.2
• /
• pp.69-76
• /
• 2009

Purpose: Various electrocardiogram (ECG) changes can occur in patients with acute organophosphate poisoning (OPP) and may be associated with the clinical severity of poisoning. The present study aimed to evaluate the extent and frequency of ECG changes and cardiac manifestations, and their association with acute OPP clinical severity. Methods: Seventy-two adult patients admitted to our emergency department with a diagnosis of acute OPP were studied retrospectively. ECG changes and cardiac manifestations at admission were evaluated. ECG changes between respiratory failure (RF) group and no respiratory failure (no RF) groups were compared. Results: Prolongation of QTc interval (n=40, 55.6%) was the most common ECG change, followed by sinus tachycardia (n=36, 50.0%). ST-T wave changes such as ST segment elevation or depression and T wave change (inversion or non-specific change) were evident in 16 patients (22.2%). Prolongation of QTc interval was significantly higher in the RF group compared with the no RF group (p=0.03), but was not an independent predictor for RF in acute OPP (OR; 4.00, 95% CI; 0.70-23.12, p=0.12). Conclusion: While patients with acute OPP can display ECG changes that include prolongation of QTc interval, sinus tachycardia, and ST-T wave changes at admission, these changes are not predictors of respiratory failure.