• 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.

• Childhood Kidney Diseases
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• v.27 no.2
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• pp.105-110
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• 2023

Purpose: To analyze electrocardiograms (ECGs) of patients with a salt-losing tubulopathy (SLT) and to determine the frequency and risk factors for long QT and arrhythmia. Methods: A total of 203 patients aged <19 years with SLT, specifically Bartter syndrome and Gitelman syndrome, who had a 12-lead ECG were included in this retrospective study. We analyzed the presence of an arrhythmia or prolonged corrected QT (QTc) on ECGs obtained for these patients. Demographic and laboratory data were compared between patients with abnormal and normal ECG findings. Results: Out of the 203 SLT patients, 38 (18.7%) underwent electrocardiography and 10 (40.0%) of 25 patients with inherited SLT had abnormal ECG findings, including prolonged QTc and arrhythmias. The abnormal ECG group had significantly lower serum potassium levels than the normal group (median [interquartile range]: 2.50 mmol/L [2.20-2.83] vs. 2.90 mmol/L [2.70-3.30], P=0.036), whereas other serum chemistry values did not show significant differences. The cutoff level for a significant difference in QTc interval was serum potassium level <2.50 mmol/L. One cardiac event occurred in a 13-year-old boy, who developed paroxysmal supraventricular tachycardia and underwent cardiac ablation. No sudden cardiac deaths occurred in this cohort. Conclusions: The incidence of ECG abnormalities in patients with inherited SLT was 40.0%, whereas the ECG screening rate was relatively low (18.7%). Therefore, we recommend ECG screening in patients with inherited SLT, especially in those with serum potassium level <2.50 mmol/L.

• Journal of Chest Surgery
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• v.42 no.2
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• pp.214-219
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• 2009

Background: Primary focal hyperhidrosis is characterized by overactivity of the sympathetic nervous function, and this has been effectively treated with endoscopic thoracic sympathetic denervation (ESD). The imbalance of sympathetic and parasympathetic nervous system that's created by ESD may affect the heart, lung and other thoracic organs. We analyzed the heart rate and ECG changes after performing ESD at our hospital, and this is the first such study that has been conducted on this. Material and Method: Of the 263 patients who underwent ESD between October 1996 and October 2006, 130 had ECG before and after ESD, and they were classified into 3 groups according to the level of ESD: Group I (n=40) patients underwent ESD at the 2nd rib (T2ESD), Group II (n=80) at the 3rd rib (T3ESD) and Group III (n=10) at the 4th rib (T4ESD). Result: There was no mortality or major morbidity. Heart rate (HR) was significantly decreased from $71.6{\pm}10.6/min\;to\;66.8{\pm}10.2/min$ after ESD (p<0.01); however, the PR (from $148.6{\pm}21.2$ msec to $152.8{\pm}20.5$ msec) and QTc (from $399.2{\pm}15.4$ msec to $404.0{\pm}15.1$ msec) intervals were significantly increased after ESD in the patients who suffered with primary hyperhidrosis (p<0.01). According to the level of ESD, there were significant changes in the HR and QTc interval in group I (T2ESD), the HR and PR interval in group II and the QTc interval in Group III. Conclusion: There were significant changes in the heart rate and ECG findings after ESD. The thoracic sympathetic denervation of T2, T3 and T4 affected the electrical activity of the heart at the resting state.

• Journal of The Korean Society of Clinical Toxicology
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• v.5 no.1
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• pp.8-14
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• 2007

Purpose: Organophosphorus insecticides tend to be regarded as a homogeneous single entity. We aimed to determine whether organophosphate poisoning differs by subgroups in clinical features and severity. Methods: We retrospectively reviewed medical records of all patients with acute organophophorus poisoning from January 1998 to December 2006. We investigated clinical features, Glasgow coma scale (GCS), laboratory findings, QTc intervals, management, and outcomes. Results: A total of 109 patients were included. The dimethoxy group experienced significantly longer times than the diethoxy group for ventilation duration (0.6 day vs. 0.2 day, p=0.006), ICU duration (2.0 day vs. 0.8 day, p=0.037), and total admission duration (2.8 day vs. 0.9 day, p=0.008), except in cases of dichlorvos poisoning. Also, the GCS of the dimethoxy group (except with dichlorvos) was significantly lower than for the diethoxy group (dimethoxy, $11.2{\pm}5.2$ vs. diethoxy, $13.8{\pm}2.4$, p= 0.021). QTc intervals for the dimethoxy group (except with dichlorvos) tended to be somewhat greater than for the diethoxy group (dimethoxy, $452.9{\pm}16.1\;msec$ vs. diethoxy, $429.6{\pm}40.9\;msec$). There were 65 patients with dichlorvos ingestion, and 2 of these patients (3%) died. Conclusion: When compared to the diethoxy group, the dimethoxy group of organophosphates (with the exception of dichlorvos) were associated with poorer prognostic value for indicators such as GCS, QTc interval, requirement for intubation, ICU duration, and total admission duration. Within the dimethoxy group, patients with dichlorvos poisoning had relatively better prognoses than for the other dimethoxy group organophosphates studied.

• YAKHAK HOEJI
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• v.50 no.2
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• pp.129-135
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• 2006

Two Antihistamines, terfenadine and astemizole have been withdrawn from major markets for the reason that these durgs have been reported to induce QT interval prolongation associated with the onset of Torsades do Pointes (TdP), resulting in a life-threatening ventricular arrhythmia. In this study, we investigated effects of diphenhydramine on electrocardiograms and hemodynamic parameters in conscious telemetered dogs. We validated and defined the sensitivity of the test system by monitoring basal parameters and using positive control substance, terfenadine. Single administration effects were tested during 24 hours for each test drug at dose 1 mg/kg, 10 mg/kg, 30 mg/kg, 100 mg/kg. We monitored QT, QTc, heart rate, blood pressure and body temperature after administering test drugs. In conscious telemetered dogs, diphenhydramine significantly prolonged $QT\;(6.8\%\;of\;basal)\;and\;QTc\;(7.8\%\;of\;basal)$ at 100 mg/kg. Other parameters were not affected significantly. These findings suggest that antihistamines could induce important clinical relevance for patients taking excessive dosages of conventional antihistamines and those at risk of developing cardiac arrhythmias. Future studies that include other antihistamines and other classes will be necessary to predict the torsadogenic risk of drugs in humans.

• Endocrinology and Metabolism
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• v.33 no.4
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• pp.485-492
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• 2018

Background: Increasing evidence supports interplay between aldosterone and parathyroid hormone (PTH), which may aggravate cardiovascular complications in various heart diseases. Negative structural cardiovascular remodeling by primary aldosteronism (PA) is also suspected to be associated with changes in calcium levels. However, to date, few clinical studies have examined how changes in calcium and PTH levels influence cardiovascular outcomes in PA patients. Therefore, we investigated the impact of altered calcium homeostasis caused by excessive aldosterone on cardiovascular parameters in patients with PA. Methods: Forty-two patients (mean age $48.8{\pm}10.9$ years; 1:1, male:female) whose plasma aldosterone concentration/plasma renin activity ratio was more than 30 were selected among those who had visited Severance Hospital from 2010 to 2014. All patients underwent adrenal venous sampling with complete access to both adrenal veins. Results: The prevalence of unilateral adrenal adenoma (54.8%) was similar to that of bilateral adrenal hyperplasia. Mean serum corrected calcium level was $8.9{\pm}0.3mg/dL$ (range, 8.3 to 9.9). The corrected calcium level had a negative linear correlation with left ventricular end-diastolic diameter (LVEDD, ${\rho}=-0.424$, P=0.031). Moreover, multivariable regression analysis showed that the corrected calcium level was marginally associated with the LVEDD and corrected QT (QTc) interval (${\beta}=-0.366$, P=0.068 and ${\beta}=-0.252$, P=0.070, respectively). Conclusion: Aldosterone-mediated hypercalciuria and subsequent hypocalcemia may be partly involved in the development of cardiac remodeling as well as a prolonged QTc interval, in subjects with PA, thereby triggering deleterious effects on target organs additively.

• Journal of The Korean Society of Clinical Toxicology
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• v.9 no.1
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• pp.20-25
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• 2011

Purpose: This study was designed to analyze the contributing factors, as well as the incidence and nature of the cardiac toxicity, in patients presenting with diphenhydramine overdose. Methods: We retrospectively reviewed the medical records of the intoxicated patients who presented to the ED of Korea University Anam Hospital from January 2008 to December 2010. Those patients who visited due to a diphenhydramine overdose were selected and the following features were recorded for analysis: the general characteristics, vital signs, the amount of ingested diphenhydramine, the time interval from ingestion to presentation, the coingested drugs (if any), the toxicities and the ECG findings. Cardiac toxicity, while defined mainly in terms of the temporary ECG changes such as QTc prolongation, right axis deviation, QRS widening, high degree AV block and ischemic changes, also encompassed cardiogenic shock, which is a clinical finding. Results: A total of eighteen patients were enrolled. Of the eighteen patients, eight had ingested diphenhydramine only, while ten had ingested other drugs in addition to diphenhydramine. The most commonly observed toxicity following diphenhydramine overdose included cardiac toxicity (78%). Cardiac toxicity was observed in all the patients who presented to the emergency department 2 hours after ingestion. The patients with QTc prolongation turned out to have ingested significantly larger amounts of diphenhydramine. Conclusion: QTc prolongation and right axis deviation were common findings for the patients with a diphenhydramine overdose. QTc prolongation was more likely to occur with ingesting larger amounts of diphenhydramine. Close monitoring is mandatory for patients who have ingested large amounts of diphenhydramine to prevent such potentially lethal cardiac toxicity.

• Journal of Veterinary Clinics
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• v.30 no.6
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• pp.456-458
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• 2013

The aim of this study is to evaluate the reference value for electrocardiogram in healthy captive raccoon dogs. Forty-one free-ranging adult raccoon dogs rescued from Wildlife rescue centre, Kangwon National University were enrolled in this study. The 6-lead electrocardiogram was obtained in all raccoon dogs without any chemical restraints. The mean heart rate was $146.10{\pm}43.31$ beats/min (95% confidence interval 132.84~159.36 beats/min). The mean respiration rate was $35.73{\pm}11.56$ breaths/min (95% confidence interval 32.19~39.27 breaths/min). The mean systolic blood pressure was $136{\pm}29.26$ mmHg (95% confidence interval 127.99~145.91 mmHg). Electrocardiographical features were also evaluated in all raccoon dogs. The mean duration and amplitude of P-wave were $38.2{\pm}4.0$ ms (range 28-40 ms) and $0.128{\pm}0.039$ mV (range 0.09~0.20). The mean duration and amplitude of QRS complexes were $48.5{\pm}7.2ms$ (range 36-60 ms) and $1.330{\pm}0.650$ mV (range 0.15~2.30). The range of the mean electrical (QRS) axis was $-91^{\circ}{\sim}+96^{\circ}$ ($10^{\circ}{\sim}60^{\circ}$; 95% of confidence interval). The mean corrected QT (QTc) interval was $273.7{\pm}32.7ms$ (range 212-333 ms), while the mean PR interval was $76.1{\pm}10.0ms$ (range 50-82 ms). To the authors' knowledge, this is the first study to provide references in electrocardiogram (ECG) in healthy captive raccoon dogs.

• 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.

• Clinical and Experimental Pediatrics
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• v.53 no.5
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• pp.644-647
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• 2010

Purpose: To evaluate myocardial conductivity to understand cardiac involvement in patients with mitochondrial disease. Methods: We performed retrospective study on fifty-seven nonspecific mitochondrial encephalopathy patients with no clinical cardiac manifestations. The patients were diagnosed with mitochondrial respiratory chain complex defects through biochemical enzyme assays of muscle tissue. We performed standard 12-lead electrocardiography (ECG) on all patients. Results: ECG abnormalities were observed in 30 patients (52.6%). Prolongation of the QTc interval (>440 ms) was seen in 19 patients (33.3%), widening of the corrected QRS interval in 15 (26.3%), and bundle branch block in four (7.0%). Atrioventricular block, premature atrial contraction and premature ventricular contraction were seen in two patients each (3.5%) and Wolff-Parkinson-White syndrome in one patient (1.8%). Conclusion: Given this finding, we recommend active screening with ECG in patients with mitochondrial disease even in patients without obvious cardiac manifestation.