• Journal of Biomedical Engineering Research
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• v.38 no.6
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• pp.313-320
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• 2017

Myocardial infarction is a disease caused by stenosis of the coronary arteries. The high risk of sudden cardiac death due to myocardial infarction has triggered related researches that have been actively studied so far. However, these studies focused on the clinical results, which are mainly based on observations of symptoms due to infarction through electrocardiograms. Therefore, in this study, we tried to analyze the behavior of heart according to the position and volume of infarction lesion through the computer simulation study using three dimensional ventricular models. In order to implement infarction, commercial software was used to simulate cell necrosis due to blockage of a specific coronary. In addition, the conduction block due to infarction was mimicked by reducing the electrical conduction in the infarcted area, which was 100 times less than the electrical conduction of the whole ventricular lattice implemented by the finite element analysis method. Thus, this study classified the infarcted cases into the upper, middle, lower, and apex according to lattice data of eight different infraction areas. In other words, we assumed that myocardial infarction would have inherent electro-dynamic characteristics depending on the location and extent, and analyzed the ventricular electromechanical responses for infarction lesions using a three dimensional cardiac physiome model. The results showed that the volume of infarction did not directly affect the cardiac responses, but the location of the infarction lesions could influence the ventricular pumping efficiency. These suggest that the occlusion of specific coronary arteries may have a fatal effect on the decline in ventricular performance. In conclusion, although location of myocardial infarction lesions is considered to be an important variable to be considered clinically rather than lesion size, quantitative predictions should be made more in the future considering physiological factors such as lesion location and direction of myocardial fiber at that location.

• The Korean Journal of Nuclear Medicine
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• v.28 no.1
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• pp.44-51
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• 1994

It is known that the normal His-Purkinje system provides for nearly synchronous activation of right (RV) and left (LV) ventricles. When His-Purkinje conduction is abnormal, the resulting sequence of ventricular contraction must be correspondingly abnormal. These abnormal mechanical consequences were difficult to demonstrate because of the complexity and the rapidity of it's events. To determine the relationship of the phase changes and the abnormalities of ventricular conduction, we performed phase image analysis of $^{99m}Tc$-RBC gated blood pool scintigrams in patients with intraventricular conduction disturbances (24 complete left bundle branch block (C-LBBB), 15 complete right bundle branch block (C-RBBB), 13 Wolff-Parkinson-White syndrome (WPW), 10 controls). The results were as follows; 1) The ejection fraction (EF), peak ejection rate (PER), and peak filling rate (PFR) of LV in gated blood pool scintigraphy (GBPS) were significantly lower in patients with C-LBBB than in controls ($44.4{\pm}13.9%$ vs $69.9{\pm}4.2%,\;2.48{\pm}0.98$ vs $3.51{\pm}0.62,\;1.76{\pm}0.71$ vs $3.38{\pm}0.92$, respectively, p<0.05). 2) In the phase angle analysis of LV, Standard deviation (SD), width of half maximum of phase angle (FWHM), and range of phase angle were significantly increased in patients with C-LBBB than in controls ($20.6{\pm}18.1$ vs $8.6{\pm}1.8,\;22.5{\pm}9.2$ vs $16.0{\pm}3.9,\;95.7{\pm}31.7$ vs $51.3{\pm}5.4$, respectively, p<0.05). 3) There was no significant difference in EF, PER, PFR between patients with the Wolff-parkinson-White syndrome and controls. 4) Standard deviation and range of phase angle were significantly higher in patients with WPW syndrome than in controls ($10.6{\pm}2.6$ vs $8.6{\pm}1.8$, p<0.05, $69.8{\pm}11.7$ vs $51.3{\pm}5.4$, p<0.001, respectively), however, there was no difference between the two groups in full width of half maximum. 5) Phase image analysis revealed relatively uniform phase across the both ventricles in patients with normal conduction, but markedly delayed phase in the left ventricle of patients with LBBB. 6) In 13 cases of WPW syndrome, the site of preexcitation could be localized in 10 cases (77%) by phase image analysis. Therefore, it can be concluded that phase image analysis can provide an accurate noninvasive method to detect the mechanical consequences of a wide variety of abnormal electrical activation in ventricles.

• Journal of Yeungnam Medical Science
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• v.4 no.2
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• pp.23-27
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• 1987

Mass electrocardiographic (ECG) examination was performed on 13,801 children (male 7,526 and female 6,275) of elementary and middle school in Taegu from May 1. 1986. to April 30. 1987. We read their ECG according to the "Pediatric Electrocardiography." The results were as following; The Incidence of ECG abnormality was 1.05%(male 1.3% and female 0.75%). Fifty eight children (0.42%) had atrial and ventricular hypertrophy; two right atrial hypertrophy, five left atrial hypertrophy, thirty five fight ventricular hypertrophy and sixteen left ventricular hypertrophy respectively. Ectopic beats occurred in 25 children (0.18%) ; They were atrial in 12 children, ventricular in 8 children and junctional in 5 children. There were 62 children (0.45%) of conduction disturbance ; They were first degree atrioventricular (A-V) block in 21 children, type I second degree A-V block in 1 child, A-V dissociation in 1 child, right bundle branch block in 36 children, left bundle branch block in 1 child and WPW syndrome in 2 children. Nonspecific ST, T changes and sinus tachycardia were found in 3 and one children respectively.

• Journal of Veterinary Clinics
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• v.24 no.3
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• pp.422-425
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• 2007

A 6-month-old intact male Jindo dog was underwent surgery for hip fracture caused by hit by a car. Routine laboratory tests performed prior to surgery found no significant abnormalities, which might increase risks associated with general anesthesia. The dog was premedicated with atropine, induced general anesthesia with thiopental sodium and maintained with isoflurane. Forty minutes after surgery, the dog was suddenly bradycardic. Atropine (18 ug/kg) was slowly infused intravenously to normalize heart rate. However, paradoxically the dog showed slower heart rate with intermittent atrioventricular block ($2^{nd}$ degree type I) after atropine infusion. The dog's rhythm was returned to normal rate 7 minutes after ephedrine was infused. This is a rare case of paradoxical atrioventricular block induced by high dose of atropine in a dog.

• Genomics & Informatics
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• v.10 no.2
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• pp.110-116
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• 2012

Recent several studies have shown that the genetic variation of SCN5A is related with atrioventricular conduction block (AVB); no study has yet been published in Koreans. Therefore, to determine the AVB-associated genetic variation in Korean patients, we investigated the genetic variation of SCN5A in Korean patients with AVB and compared with normal control subjects. We enrolled 113 patients with AVB and 80 normal controls with no cardiac symptoms. DNA was isolated from the peripheral blood, and all exons (exon 2-exon 28) except the untranslated region and exon-intron boundaries of the SCN5A gene were amplified by multiplex PCR and directly sequenced using an ABI PRISM 3100 Genetic Analyzer. When a variation was discovered in genomic DNA from AVB patients, we confirmed whether the same variation existed in the control genomic DNA. In the present study, a total of 7 genetic variations were detected in 113 AVB patients. Of the 7 variations, 5 (G87A-A29A, intervening sequence 9-3C>A, A1673G-H558R, G3578A-R1193Q, and T5457C-D1819D) have been reported in previous studies, and 2 (C48G-F16L and G3048A-T1016T) were novel variations that have not been reported. The 2 newly discovered variations were not found in the 80 normal controls. In addition, G298S, G514C, P1008S, G1406R, and D1595N, identified in other ethnic populations, were not detected in this study. We found 2 novel genetic variations in the SCN5A gene in Korean patients with AVB. However, further functional study might be needed.

• Journal of Chest Surgery
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• v.23 no.1
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• pp.16-21
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• 1990

From November 1978 through June 1989, 33 patients aged 3 months to 27 years [mean 9.7 years] underwent repair of intracardiac defects associated with corrected transposition. Five patients had had previous palliative surgery. Operation were performed in 31 for ventricular septal defect, 22 for pulmonary outflow tract obstruction, 16 for atrial septal defect, and 5 for anatomical tricuspid valve regurgitation. Pulmonary outflow tract obstruction was relieved by pulmonary valvotomy in 9, Rastelli procedure in 5, modified Fontan procedure in 3, and by REV procedure in 5 patients recently. Early mortality was 21.2%[7/33] and no late mortality during follow up period. Two had residual pulmonary outflow tract obstruction and one residual VSD. In eight patients, transient arrhythmia was found but soon returned to sinus rhythm. Five patients developed complete heart block and 2 were given permanent pacemaker insertion. There were 8 RBBB, 1 LBBB and one second degree atrioventricular block patients, but all showed no clinical significance. This report suggests that surgical repair of intracardiac defects associated with corrected transposition can be achieved with acceptable low risk. Though the mortality is still high, we can improved the result by advancing surgical technique, knowledge of the special conduction system, and by improving postoperative care.

• Journal of Chest Surgery
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• v.9 no.2
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• pp.198-206
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• 1976

A Total of Forty eight patients underwent open-heart surgery for correction of tetralogy of Fallot at the Seoul National University Hospital from January 1974 to October 1976, with an overall survival rate of 77 per cent. Operative mortality varied according to severity of the lesion, age of the patient, nature of previous surgical treatment and presence or absence of an outflow tract patch across the pulmonary valve ring. Eleven patients died in the early postoperative period and thirty seven patients were discharged from the hospital alive. A patch of the right ventricular outflow tract and pulmonary annulus was required to relieve pulmonic stenosis in 24 patients. There were 10 deaths in this group (42%) as compared to 1 death in the group of 24 patients who were corrected without a patch. Operative mortality was especially higher when an inlay patch was placed across the pulmonary valve ring. This may be related to the possibly greater anatomic severity of these cases and to the longer operating time when a patch was used. The electrocardiogram showed right ventricular hypertrophy in 35 cyanotic patients. Intraventricular conduction was normal in 34 patients before operation. It was normal postoperatively in only 5 of 34 patients in this group who survived surgery. Complete right bundle branch block appeared at operation in 21 patients, and 8 patients developed incomplete right bundle branch block. Major causes of death were progressive cardiac failure (4), Complete atrioventricular dissociation (3), bleeding (2), cardiac tamponade (1), and sudden cardiac arrest (1)

• Journal of Chest Surgery
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• v.46 no.4
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• pp.289-292
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• 2013

Through the use of a dual chamber (DDD) pacemaker, we achieved a cardiac resynchronization effect in a 51-year-old female patient who was transferred to our hospital from another hospital for an operation for three-vessel coronary artery disease. Her electrocardiogram showed a left bundle branch block (LBBB) and a prolonged QRS interval of 166 milliseconds. Severe left ventricle (LV) dysfunction was diagnosed via echocardiography. Coronary artery bypass grafting (CABG) was then performed. In order to accelerate left atrial activation and reduce the conduction defect, DDD pacing using right atrial and left and right ventricular pacing wires was initiated postoperatively. The cardiac output was measured immediately, and one and twelve hours after arrival in the intensive care unit. The cardiac output changed from 2.8, 2.4, and 3.6 L/min without pacing to 3.5, 3.4, and 3.5 L/min on initiation of pacing. The biventricular synchronization using DDD pacing was turned off 18 hours after surgery. She was transferred to a general ward with a cardiac output of 3.9 L/min. In patients with coronary artery disease, severe LV dysfunction, and LBBB, cardiac resynchronization therapy can be achieved through DDD pacing after CABG.

• The Korean Journal of Pain
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• v.32 no.3
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• pp.206-214
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• 2019

Background: Although case reports have suggested that the erector spinae plane block (ESPB) may help analgesia for patients after breast surgery, no study to date has assessed its effectiveness. This retrospective observational study analyzed the analgesic effects of the ESPB after total mastectomy. Methods: Forty-eight patients were divided into an ESPB group (n = 20) and a control group (n = 28). Twenty patients in the control group were selected by their propensity score matching the twenty patients in the ESPB group. Patients in the ESPB group were injected with 30 mL 0.375% ropivacaine, followed by catheter insertion for further injections of local anesthetics every 12 hours. Primarily, total fentanyl consumption was compared between the two groups during the first 24 hours postoperatively. Secondary outcomes included pain intensity levels (visual analogue scale) and incidence of postoperative nausea and vomiting (PONV). Results: Median cumulative fentanyl consumption during the first 24 hours was significantly lower in the ESPB ($33.0{\mu}g$; interquartile range [IQR], $27.0-69.5{\mu}g$) than in the control group ($92.8{\mu}g$; IQR, $40.0-155.0{\mu}g$) (P = 0.004). Pain level in the early postoperative stage (<3 hr) and incidence of PONV (0% vs. 55%) were also significantly lower in the ESPB group compared to the control (P = 0.001). Conclusions: Intermittent ESPB after total mastectomy reduces fentanyl consumption and early postoperative pain. ESPB is a good option for multimodal analgesia after breast surgery.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1219-1224
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• 2004

The objective of this study is to propose an experimental calibration facility in which a heat flux sensor can be calibrated under conductive condition by using helium gas. The heat flux calibration facility was designed, simulated and manufactured for use in a high heat transfer condition. It delivers heat fluxes up to a maximum of 35 KW $m^{-2}$. A copper block heated electrically with 3.5 KW power is designed to produce uniform temperature up to 600 K across its face. High heat fluxes are provided between hot plate and cold plate by 1 mm height helium filled gap. A cold plate is maintained around 300 K through pool boiling using a refrigerant and water-cooled heat exchanger. A simulation was conducted to verify the design of the main test section. To verify the performance of calibration facility, a heat flux sensor was examined. The measured heat fluxes were compared to the calculated one.