• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.203-204
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• 1998

ECG analysis is main techniques for diagnosing heart disease. In recent, some studies have been performed about detection of QT interval. But, it's difficult to detect QT interval because T wave is evasive. In this paper, we have detected peak point and end point of T wave and calculated QT interval. And the result has been compared with the other algorithm after detection of QT interval.

• Korean Journal of Biological Psychiatry
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• v.19 no.1
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• pp.38-44
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• 2012

Objectives : QT interval prolongation and dispersion known as indicators of an increased risk for ventricular arrhythmias and sudden death have been reported to be prolonged in patients with anorexia nervosa. The aims of this study were to compare conduction abnormalities in Korean patients with anorexia nervosa and bulimia nervosa, and to examine its relation with clinical and laboratory factors. Methods : We retrospectively examined 45 women with anorexia nervosa and 75 women with bulimia nervosa who were assessed by 12-lead electrocardiogram at baseline. QT interval and corrected QT interval, QT dispersion of the difference between the longest and shortest QT intervals, and abnormal U wave were measured for conduction abnormalities. Results : QT interval was significantly longer in patients with anorexia nervosa compared with those with bulimia nervosa. There were no differences in QTc (Corrected QT), QTd (QT dispersion) and abnormal U wave between patients with anorexia nervosa and those with bulimia nervosa. QTd was significantly correlated with the lowest ever lifetime body mass index ($kg/m^2$) as well as the serum amylase level in patients with anorexia nervosa. Conclusions : These results suggest some conduction abnormalities reported in patients with anorexia nervosa are also found in patients with bulimia nervosa. It appears that severity of weight loss and purging behavior could affect the cardiac arrhythmia in patients with eating disorders. Appropriate attention should be paid to cardiac involvement in patients with eating disorders.

• Neonatal Medicine
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• v.28 no.1
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• pp.59-63
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• 2021

An important, albeit rare, cause of fetal bradycardia is long QT syndrome (LQTS). Congenital LQTS is an ion channelopathy caused by mutations in genes encoding cardiac ion channel proteins. Fetal onset of LQTS imposes high risk of life-threatening tachyarrhythmias and sudden cardiac death. Here, we report the case of a female newborn with fetal onset of bradycardia and a 2:1 atrioventricular (AV) block. After birth, a 12-lead electrocardiogram (ECG) revealed bradycardia with QT prolongation of a corrected QT (QTc) interval of 680 ms and pseudo 2:1 AV block. Genetic testing identified a heterozygous Gly402Ser (c.1204G>A) mutation in CACNA1C, confirming the diagnosis of LQTS type 8 (LQT8). The patient received propranolol at a daily dose of 2 mg/kg. Mexiletine was subsequently administered owing to the sustained prolongation of the QT interval and pseudo 2:1 AV block. One week after mexiletine inception, the ECG still showed QT interval prolongation (QTc, 632 ms), but no AV block was observed. There were no life-threatening tachyarrhythmias in a follow-up period of 13 months.

• Biomolecules & Therapeutics
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• v.17 no.1
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• pp.1-11
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• 2009

Since the Committee for Proprietary Medicinal Products (CPMP) of the European Union issued in 1997 a "points to consider" document for the assessment of the potential for QT interval prolongation by non-cardiovascular agents to predict drug-induced torsades de pointes (TdP), the QT liability has become the critical safety issue in the development of pharmaceuticals. As TdP is usually linked to delayed cardiac repolarization, international guideline (ICH S7B) has advocated the standard repolarization assays such as in vitro IKr (hERG current) and in vivo QT interval, or in vitro APD (as a follow up) as the best biomarkers for predicting the TdP risk. However, the recent increasing evidence suggests that the currently used above biomarkers and/or assays are not fully predictive for TdP, but also does not address potential new druginduced TdP due to the selective disruption of hERG protein trafficking to the cell membrane or VT and/or VF with QT shortening. There is, therefore, an urgent need for other surrogate markers or assays that can predict the proarrhythmic potential of drug candidate. In this review, we provide an ideal pre-clinical strategy to predict the potentials of QT liability and lethal arrhythmia of the drug candidates with recent issues in this field in mind, not at the expense of discarding therapeutically innovative drugs.

• Journal of Dental Anesthesia and Pain Medicine
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• v.17 no.4
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• pp.323-327
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• 2017

QT prolongation is an electrocardiographic change that can lead to lethal arrhythmia. Acquired QT prolongation is known to be caused by drugs and electrolyte abnormalities. We report three cases in which the prolonged QT interval was improved at the time of operation by briefly discontinuing the drugs suspected to have caused the QT prolongation observed on preoperative electrocardiography. The QTc of cases 1, 2, and 3 improved from 518 to 429 ms, 463 to 441 ms, and 473 to 443 ms on discontinuing the use of a gastrointestinal prokinetic agent, a proton pump inhibitor, and a molecular targeted drug, respectively. These cases were considered to have drug-induced QT prolongation. We reaffirmed that even drugs administered for conditions unrelated to cardiac diseases can have adverse side effect of QT prolongation. In conclusion, our cases indicate that dental surgeons should be aware of the dangerous and even potentially lethal side effects of QT prolongation. For safe oral and maxillofacial surgery, cooperation with medical departments in various fields is important.

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

• Journal of Biomedical Engineering Research
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• v.11 no.1
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• pp.57-64
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• 1990

This study describes the design of the portable intelligent QT analyzer which can record and analyze the ambulatory ECG data. System hardware is consisted of the one chip microcomputer(80C31) , A/D, ROM, RAM, LCD display and preamplifier. ECG data were processed by the differentiator and the digital filter. The de- tection of the parameters-QT, QTP and RR interval-was accomplished by the software algorithm using the slope and the amplitude of the processed data. Using this system, the trends of the parameters obtained during the long term could be observed.

• Biomedical Science Letters
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• v.16 no.4
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• pp.299-305
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• 2010

KCNE1 is the causal gene of long QT syndrome. KCNE1 gene is located in chromosome 21. In compliance with this KCNE1 gene the proteins come out. KCNE1 is responsible for $K^+$ channel which maintains the normal function of the heart muscle for contraction. Affected individuals manifest prolongation of the QT interval on electrocardiongrams, a sign of abnormal cardiac repolarization. The clinical features of LQT result from episodic cardiac arrhythmias, such as torsade de pointes and ventricular fibrllation. Blood DNA was isolated and kept in $4^{\circ}C$ refrigerator. The KCNE1 gene was amplified by PCR method and about 414 bp band was identified by agarose gel electrophoresis. PCR products were inserted into pGEX-4T-1 vector in order to express KCNE1 protein after treatment with IPTG SDS-PAGE was carried out and the protein band which was about 47 kDa was clearly odserved. Results of this study would contribute to the detailed understanding of KCNE1 protein function and to designing better treatment of Long QT symdrome.

• The Korean Journal of Pain
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• v.13 no.1
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• pp.115-118
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• 2000

Stellate ganglion block is most commonly used in pain clinic because it is an easy procedure and it has broad indications reported that Angina pectoris, tachyarrhythmia and long QT syndrome (LQTS) are indicated. LQTS is a disorder of the abnormalities of cardiac sympathetic innervation and of myocardial repolarization. LQTS is characterized by marked prolongation of the QT interval, often manifestating as syncope, seizures, or sudden death due to polymorphic ventricular tachyarrhythmia known as torsades de pointes. Treatment of symptomatic patients usually begin with beta blocker. The elective treatment of LQTS patients unresponsive to beta blocker is the left cardiac sympathetic denervation. We report a case of LQTS patient who had received stellate ganglion block.

• Korean Journal of Biological Psychiatry
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• v.7 no.2
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• pp.191-197
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• 2000

Objectives : Risperidone is a new antipsychotic drug developed to overcome the therapeutic limitation of conventional antipsychotics. It responses to negative as well as positive symptoms by blocking both dopaminergic and serotonergic receptors, causing no significant side effects such as agranulocytosis and seizure. It is, however, not known whether it induces any serious cardiovascular side effects as evoked by other conventional antipsychotic drugs. The aims of this study were to evaluate the effect of risperidone on cardiovascular function, and to discuss the factors affecting the cardiovascular function. Methods : For 42 patients(22 males and 20 females) diagnosed as schizophrenia, schizophreniform disorder or schizoaffective disorder according to the DSM-IV classification, the cardiovascular fuctions such as heart rate, systolic and diastolic blood pressure, PR interval, QRS interval and QT interval were successively checked before and after 2 weeks and 4 weeks risperidone administration. Furthermore, variables such as body weight, Brief Psychiatric Rating Scale(BPRS), Clinical Global Impression(CGI), Extrapyramidal Symptom Rating Scale(ESRS), Anticholinergic Rating Scale(ARS), serum cholesterol level, serum triglyceride level, serum high-density-lipoprotein level, serum WBC, serum Hb, serum platelet level, prothrombin time and partial thromboplastin time were also analyzed before and after 2 weeks and 4 weeks risperidone administration. Results : 1) Risperidone treatment resulted in a significantly decreased heart rate and increased QT interval after 4 weeks administration(p<0.005 respectively). 2) The scores of BPRS and CGI were significantly decreased after 2 weeks and 4 weeks risperidone administration as compared with baseline(p<0.001 respectively). The scores of ESRS and ASRS were significantly increased after 2 weeks and 4 weeks risperidone administration as compared with baseline(p<0.001 respectively). 3) There were positive correlations between heart rate after 4 weeks and total dose(P<0.05). Blood pressure was significantly(p<0.05) correlated with sex(higher in male) and significantly(p<0.05) positive correlated with body weight. QT interval was significantly(p<0.05) correlated with sex(longer in female) and smoking history(shorter in smokers). Conclusions : Risperidone could induce significant change in heart rate and Q-T interval. Therefore, the cardiovascular safety for risperidone should be reconsidered according to the duration and dosage increase.