• The Korean Journal of Physiology and Pharmacology
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• v.6 no.1
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• pp.1-7
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• 2002

Congenital Long QT syndrome (LQTs) is a relatively rare pathologic disorder but results frequently in sudden cardiac death. Of the six LQTs that have been clinically described, five have been worked out for their genetic and biophysical profile. Most are generated by mutations which cause a loss of function in two delayed $K^+$ currents, $i_{Ks}\;and\;i_{Kr}.$ One syndrome is generated by mutations in the $Na^+$ channel which causes essentially a gain of function in the channel. Clinically the syndromes are characterized by slowed repolarization of the cardiac ventricular action potential and the occurrence of typical arrhythmias with undulating peaks in the electrocardiogram, called Torsade de Pointes. Arrhythmias are initiated by early or delayed afterdepolarizations and continue as reentry. Triggers for cardiac events are exercise (swimming; LQT1), emotion (arousal; LQT2) and rest/sleep (LQT3). ${\beta}-blockers$ have a high efficacy in the treatment of LQT1 and LQT2. In LQT3 their use is questionable. The study of congenital LQTsyndromes is a remarkable example of how basic and clinical science converge and take profit of each other's contribution.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.275-278
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• 1997

Standard methods estimating the power spectral density(PSD) from an irregularly sampled cardiac event series require deriving a new evenly-spaced signal applicable to those methods. To avoid that requirement, in this study, the power spectrum of heart rate variability was estimated by Lomb-Scargle's algorithm, which is a means of obtaining PSD estimates directly from irregularly sampled timeseries observed in astronomy. To assess the performance of Lomb-Scargle algorithm in the power spectral analysis of heart rate variability, it was applied to various cardiac event series derived through integral pulse frequency modulation model(IPFM) simulation and from real ECG signals, and the resultant power spectra was compared with those obtained by a conventional method based on the FFT. In result, it is concluded that Lomb-Scargle's periodogram is very effective in the power spectral analysis of heart rate variability, especially in the presence of arrhythmia and/or dropouts of cardiac events.

• Progress in Medical Physics
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• v.30 no.4
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• pp.150-154
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• 2019

The objective of this study is to monitor the radiation doses delivered to a cardiac implantable electronic device (CIED) by comparing the absorbed doses calculated by a commercial treatment planning system (TPS) to those measured by an in vivo dosimeter. Accurate monitoring of the radiation absorbed by a CIED during radiotherapy is necessary to prevent damage to the device. We conducted this study on three patients, who had the CIED inserted and were to be treated with radiotherapy. Treatment plans were generated using the Eclipse system, with a progressive resolution photon optimizer algorithm and the Acuros XB dose calculation algorithm. Measurements were performed on the patients using optically stimulated luminescence detectors placed on the skin, near the CIED. The results showed that the calculated doses from the TPS were up to 5 times lower than the measured doses. Therefore, it is recommended that in vivo dosimetry be conducted during radiotherapy for CIED patients to prevent damage to the CIED.

• Journal of Chest Surgery
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• v.40 no.9
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• pp.633-636
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• 2007

Coronary artery spasm immediately after the coronary artery bypass graft (CABG) surgery is rare but it can cause sudden and severe hypotension or a ventricular arrhythmia. We report a case of low cardiac output syndrome caused by a right coronary artery spasm following CABG that did not show any significant stenotic lesions on preoperative coronary angiography.

• Journal of Chest Surgery
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• v.40 no.3 s.272
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• pp.220-224
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• 2007

Extracorporeal membrane oxygenation (ECMO) provides mechanical cardiopulmonary support and has been used for children with severe respiratory failure, intractable heart failure, sepsis, pulmonary hypertension, and as a bridge to heart transplantation. There have been few reports of the use of ECMO to provide cardiac support in children with low cardiac output as a result of arrhythmias. We report the case of a 15-year-old female with circulatory collapse due to refractory ventricular arrhythmia after one and a half repair in Ebstein's anomaly, who was successfully resuscitated using ECMO.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.8
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• pp.585-589
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• 2016

Recently, the robotic assist system for cardiovascular intervention gets continuously growing interest. The robotic cardiovascular intervention systems are largely two folds, systems for cardiac ablation procedure assist and systems for vascular intervention assist. For the systems, the clinician controls the catheter inserted through blood vessel to the heart via a master console or master manipulator. Most of the current master manipulators have structure of joystick-like pivoting 2 degree of freedom (DOF) handle in the core, which is used in parallel with other sliding switches and input devices. It however is desirable to have customized and optimized design manipulator that can provide clinician with intuitive control of the catheter motion fully utilizing the advantage of the use of robotic structure. A 6 DOF kinematic mechanism that can capture the motion control intention of the clinician in translational 3 DOF and rotational 3 DOF is proposed in this paper. Also, a master-slave motion relationship specially designed for the cardiac catheter manipulation motion is proposed and implemented in an experimental prototype. Design revision for implementation of more efficient motion and experiment in combination with an experimental slave robot system for catheter manipulation are underway.

• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.1
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• pp.1-10
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• 2015

This article is a study on palpitation of which disease cause, disease mechanism and formulas were analyzed with reference to annotations on "Shanghanlun" and "Jinkuiyaolue". And the scope of modern diseases related with palpitation was drawn by research on clinical papers. The source books are "Zhujieshanghanlun" and "Jinkuiyaoluefanglun" and the clinical papers are searched in China Academic Journals(CAJ) of China National Knowledge Infrastructure(CNKI). 13 clauses in "Shanghanlun" and 9 clauses in "Jinkuiyaolue" and 12 formulas are related with palpitation. Disease mechanisms of palpitation were classified as yang deficiency, yin deficiency, qi deficiency, blood deficiency, retained fluid, cold, etc and these days, qi stagnation, phlegm turbidity, blood stasis and fire heat are also considered as disease mechanisms. Modern diseases related with palpitation are arrhythmia(extrasystole, atrial fibrillation, bradycardia, tachycardia, sick sinus syndrome, atrioventricular block), vascular diseases(arterial occlusion, phlebothrombosis, Buerger's disease, coronary artery disease, vasculitis), blood pressure disorder(hypertension, hypotension) and heart diseases such as heart failure, angina pectoris, myocardial infarction, myocarditis, cardiomyopathy, pericardial effusion. And diseases related with psychological change(cardiac neurosis, anxiety neurosis, neurosis, depression, hyperthyroidism, hypothyroidism), pyrexia, anemia, drug intoxication, etc are also related with palpitation. Zhen Wu Tang showing an efficacy in dilating blood vessels and strengthening cardiac function, Wuling Powder with diuretic effect and Fried Glycyrrhizae Decoction acting on the ${\beta}$ receptor are applied to heart failure in different ways. Fried Glycyrrhizae Decoction(308 cases), Zhen Wu Tang(154), Wuling Powder(54), Xiao Chaihu Tang(34), Sini San(20) are reported to have been clinically applied to cardiovascular diseases and Zhen Wu Tang and Wuling Powder mainly applied to heart failure, Fried Glycyrrhizae Decoction, Lizhong Wan, Sini San and Zhen Wu Tang chiefly applied to arrhythmia related diseases. This study focuses on the general research and consideration on clinical applications and is a preliminary study to understand relations between Korean Medicine's symptoms and categories of modern diseases.

• Korean Circulation Journal
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• v.53 no.4
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• pp.239-250
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• 2023

Background and Objectives: Brugada syndrome (BrS) is an inherited arrhythmia syndrome that presents as sudden cardiac death (SCD) without structural heart disease. One of the mechanisms of SCD has been suggested to be related to the uneven dispersion of transient outward potassium current (I_to) channels between the epicardium and endocardium, thus inducing ventricular tachyarrhythmia. Artemisinin is widely used as an antimalarial drug. Its antiarrhythmic effect, which includes suppression of I_to channels, has been previously reported. We investigated the effect of artemisinin on the suppression of electrocardiographic manifestations in a canine experimental model of BrS. Methods: Transmural pseudo-electrocardiograms and epicardial/endocardial transmembrane action potentials (APs) were recorded from coronary-perfused canine right ventricular wedge preparations (n=8). To mimic the BrS phenotypes, acetylcholine (3 μM), calcium channel blocker verapamil (1 μM), and I_to agonist NS5806 (6-10 μM) were used. Artemisinin (100-150 μM) was then perfused to ameliorate the ventricular tachyarrhythmia in the BrS models. Results: The provocation agents induced prominent J waves in all the models on the pseudo-electrocardiograms. The epicardial AP dome was attenuated. Ventricular tachyarrhythmia was induced in six out of 8 preparations. Artemisinin suppressed ventricular tachyarrhythmia in all 6 of these preparations and recovered the AP dome of the right ventricular epicardium in all preparations (n=8). J wave areas and epicardial notch indexes were also significantly decreased after artemisinin perfusion. Conclusions: Our findings suggest that artemisinin has an antiarrhythmic effect on wedge preparation models of BrS. It might work by inhibition of potassium channels including I_to channels, subsequently suppressing ventricular tachycardia/ventricular fibrillation.

• Journal of Chest Surgery
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• v.33 no.3
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• pp.207-211
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• 2000

Backgroud: Conventional cardiac transplantation with each atrial anastomosis designed by Shumway and associates has been used widely in cardiac transplantation because of its simplicity and efficiency. There have been many reports about the postoperative atrioventricular value regurgitation resulting from the alteration in atrial geometry after cardiac transplantation by Shumway's technique. New surgical technique of direct anastomosis of superior vena cava, inferior vena cava, right pulmonary vein and left pulmonary vein was introduced to overcome the those problems. We performed this study to test the feasibility of this new surgical technique prior to application to clinical practice. Material and Method: Conventional cardiac transplantation was performed on 12 mongrel dogs(Group I) and cardiac transplantation with new surgical mthod of direct anastomosis of SVC, IVC, left and right pulmonary veins was performed on 11 mongrel dogs(Group II). After weaning from cardiopulmonary bypass, we compared the postoperative rhythm, hemodynamic data, and echocardiographic findings between two groups. Result : The cardiopulmonary bypass time and graft ischemic time were 119.0$\pm$4.4 minutes, 162.0$\pm$4.5 minutes respectively in group I, and 140.0$\pm$7.1 minutes, 180.5$\pm$5.4 minutes respectively in group II. The cardiopulmonary time and graft ischemic time in group II were longer than those of group I (p<0.05). There were 3 cases of failure to weaning from cardipulmonary bypass onein group I and two in group II, and this difference was not significant statistically. Sinus rhythm was regained postoperatively in 58% (group I) and 82%(group II), without statistical significant between 2 groups. Postoperative echolcardiography showed 2 cases of tricuspid value regurgitation and 1 case of mitral regurgitation in group I, and no regurgitation of atrioventricular value in group II. Conclusion: Although these was no statistically significant difference between 2 groups, there was tendency of less arrhythmia and less atrioventricular valvular regurgitation in group II. We suggested that the new surgical technique could be a useful strategy in heart transplantation, especially in the case of size mismatching between donor and recipient.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.1
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• pp.119-127
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• 2016

Dihydropyridine (DHP) calcium channel blockers (CCBs) have been widely used to treat of several cardiovascular diseases. An excessive shortening of action potential duration (APD) due to the reduction of $Ca^{2+}$ channel current ($I_{Ca}$) might increase the risk of arrhythmia. In this study we investigated the electrophysiological effects of nicardipine (NIC), isradipine (ISR), and amlodipine (AML) on the cardiac APD in rabbit Purkinje fibers, voltage-gated $K^+$ channel currents ($I_{Kr}$, $I_{Ks}$) and voltage-gated $Na^+$ channel current ($I_{Na}$). The concentration-dependent inhibition of $Ca^{2+}$ channel currents ($I_{Ca}$) was examined in rat cardiomyocytes; these CCBs have similar potency on $I_{Ca}$ channel blocking with $IC_{50}$ (the half-maximum inhibiting concentration) values of 0.142, 0.229, and 0.227 nM on NIC, ISR, and AML, respectively. However, ISR shortened both $APD_{50}$ and $APD_{90}$ already at $1{\mu}M$ whereas NIC and AML shortened $APD_{50}$ but not $APD_{90}$ up to $30{\mu}M$. According to ion channel studies, NIC and AML concentration-dependently inhibited $I_{Kr}$ and $I_{Ks}$ while ISR had only partial inhibitory effects (<50% at $30{\mu}M$). Inhibition of $I_{Na}$ was similarly observed in the three CCBs. Since the $I_{Kr}$ and $I_{Ks}$ mainly contribute to cardiac repolarization, their inhibition by NIC and AML could compensate for the AP shortening effects due to the block of $I_{Ca}$.