• Journal of Chest Surgery
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• v.51 no.4
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• pp.266-272
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• 2018

Background: Limited comparative data are available on the efficacy of cryoablation versus radiofrequency ablation in patients with atrial fibrillation. This study aimed to compare radiofrequency ablation and cryoablation with regard to clinical outcomes and the restoration of sinus rhythm or atrial contractility. Methods: A total of 239 patients who underwent surgical ablation between August 2003 and December 2016 at our institution were included. The patients were divided into 2 groups according to the energy device that was used (group A: n=140, radiofrequency ablator; group B: n=99, cryoablator). Echocardiographic data, overall survival, and major cardiovascular and cerebrovascular event (MACCE)-free survival were compared between the 2 groups. Results: At 1 year of follow-up, the atrial contractility recovery rate was 32.2% (19 of 59) in group A and 48.8% (21 of 44) in group B. In addition, cryoablation was found to be a predictive factor for the recovery of atrial contractility (cryoablation vs. radiofrequency ablation: odds ratio, 2.540; 95% confidence interval, 1.063-6.071; p=0.036). The left ventricular ejection fraction was significantly higher in group B ($53.1%{\pm}11.5%$ vs. $59.1%{\pm}6.3%$, p=0.001). The median follow-up duration was 36 months. The 5-year overall survival rate was $80.1%{\pm}3.6%$ in group A and $92.1%{\pm}2.9%$ in group B (p=0.400). The 5-year MACCE-free survival rate was $70.3%{\pm}4.0%$ in group A and $70.9%{\pm}5.6%$ in group B (p=0.818). Conclusion: Cryoablation was associated with a higher atrial contractility restoration rate and better left ventricular function than radiofrequency ablation. However, no significant relationship was observed between the energy source and overall or MACCE-free survival.

• Progress in Superconductivity
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• v.7 no.1
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• pp.28-35
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• 2005

We propose a method to measure atrial arrhythmias (AA) such as atrial fibrillation (Afb) and atrial flutter (Afl) with a SQUID magnetocardiograph (MCG) system. To detect AA is one of challenging topics in MCG. As the AA generally have irregular rhythm and atrio-ventricular conduction, the MCG signal cannot be improved by QRS averaging; therefore a SQUID MCG system having a high SNR is required to measure informative atrial excitation with a single scan. In the case of Afb, diminished f waves are much smaller than normal P waves because the sources are usually located on the posterior wall of the heart. In this study, we utilize an MCG system measuring tangential field components, which is known to be more sensitive to a deeper current source. The average noise spectral density of the whole system in a magnetic shielded room was $10\;fT/{\surd}Hz(a)\;1\;Hz\;and\;5\;fT/{\surd}Hz\;(a)\;100\;Hz$. We measured the MCG signals of patients with chronic Afb and Afl. Before the AA measurement, the comparison between the measurements in supine and prone positions for P waves has been conducted and the experiment gave a result that the supine position is more suitable to measure the atrial excitation. Therefore, the AA was measured in subject's supine position. Clinical potential of AA measurement in MCG is to find an aspect of a reentry circuit and to localize the abnormal stimulation noninvasively. To give useful information about the abnormal excitation, we have developed a method, separative synthetic aperture magnetometry (sSAM). The basic idea of sSAM is to visualize current source distribution corresponding to the atrial excitation, which are separated from the ventricular excitation and the Gaussian sensor noises. By using sSAM, we localized the source of an Afl successfully.

• The Korean Journal of Emergency Medical Services
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• v.8 no.1
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• pp.149-160
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• 2004

Background : To save out-of-hospital cardiac arrest cases is a major concern for Korea. Cardiac arrest is a very common problem, with > 18,000 cases dying each year in Korea. Overall, survival to hospital discharge remains poor. Resuscitation has become an important multidisciplinary branch of medicine, demanding a spectrum of skills and attracting a plethora of specialities and organizations. Since the "Utstein Style" was advocated in 1991, many reports about out-of-hospital cardiac arrest have been published based on this guideline. These differences prevent valid inter-hospital and international comparisons. However, we do not know the true effectiveness of resuscitation. There are no guideline for reviewing, reporting, conducting research on resuscitation in Korea. This study evaluated the out-of-hospital factor associated with survival discharge of out-of-hospital cardiac arrest, was especially to provide basic data for the unified reporting guideline of resuscitation in Korea. Methods : From January 1990 to July 2004, we collected data about out-of-hospital cardiac arrest at Wonju Christian Hospital(WCH-CAD), Ewha Women University Mokdong Hospital(Ewha-CAD), I used same record form based on the "Utstein Style". The "Utstein Style" is internationally recommended guidelines for reporting outcome data from resuscitation events. Results : Resuscitation was performed in 1443 out-of-hospital cardiac arrest patients at 2 hospitals. Five hundred eighty(40.25%) patients recovered the spontaneous circulation at least once and One hundred sixty eight(11.66%) patients discharged alive. Initial EKG showed Ventricular Tachycardia/Ventricular Fibrillation in One hundred thirty five(9.33%) patients, asystole in one thousand nine(69.73%) patients and other rhythms in one hundred thirty nine(20.94%) patients. Among one hundred two cardiogenic cardiac arrest patients, two(2.0%) patients was discharged alive. Conclusion : Overall survival rate of out-of-hospital cardiac arrest patients was 11.66% which was poorer than that of the western country. The proportion of the cardiogenic cause was 33.38% which was only half of the western country. VT/VF is relatively not common ac a initial EKG rhythm. These differences might be to due difference in the prevalence pattern of out-of-hospital cardiac arrest as well as prematurity of the EMSS. It is needed that the best survival can be achieved if all following links have been optimized : rapid access, early CPR, early defibrillation, early ACLS.

• The Korean Journal of Emergency Medical Services
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• v.20 no.2
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• pp.7-19
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• 2016

Purpose: To investigate the effect of early hypothermia on post-resuscitation myocardial recovery and survival time after cardiac arrest and resuscitation in a rat model of myocardial infarction(MI). Methods: Thoracotomies were performed in 10 male Sprague Dawley rats weighing 450-455g. Myocardial infarction was induced by ligation of the left anterior descending coronary artery. Ninety minutes after arterial ligation, ventricular fibrillation was induced, cardiopulmonary resuscitation was subsequently performed before defibrillation was attempted. Animals were randomized to control group and experimental group(acute MI-normothermia)($32^{\circ}C$ for 4 hours). Duration of survival was recorded. Myocardial functions, including cardiac output, left ventricular ejection fraction, and myocardial performance index were measured using echocardiography. Results: Myocardial function was significantly better in hypothermia group than the control group during the first 4 hours post-resuscitation. The survival time of the experimental group was greater than that of the control group(p<.050). Conclusion: This study suggests that early hypothermia can attenuate post-resuscitation myocardial dysfunction after acute myocardial function, and may be a useful strategy in post-resuscitation care.

• Journal of Cardiovascular Imaging
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• v.31 no.3
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• pp.125-132
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• 2023

BACKGROUND: There is limited data on the residual echocardiographic findings including strain analysis among post-coronavirus disease (COVID) patients. The aim of our study is to prospectively phenotype post-COVID patients. METHODS: All patients discharged following acute COVID infection were systematically followed in the post-COVID-19 Recovery Clinic at Vancouver General Hospital and St. Paul's Hospital. At 4-18 weeks post diagnosis, patients underwent comprehensive echocardiographic assessment. Left ventricular ejection fraction (LVEF) was assessed by 3D, 2D Biplane Simpson's, or visual estimate. LV global longitudinal strain (GLS) was measured using a vendor-independent 2D speckle-tracking software (TomTec). RESULTS: A total of 127 patients (53% female, mean age 58 years) were included in our analyses. At baseline, cardiac conditions were present in 58% of the patients (15% coronary artery disease, 4% heart failure, 44% hypertension, 10% atrial fibrillation) while the remainder were free of cardiac conditions. COVID-19 serious complications were present in 79% of the patients (76% pneumonia, 37% intensive care unit admission, 21% intubation, 1% myocarditis). Normal LVEF was seen in 96% of the cohort and 97% had normal right ventricular systolic function. A high proportion (53%) had abnormal LV GLS defined as < 18%. Average LV GLS of septal and inferior segments were lower compared to that of other segments. Among patients without pre-existing cardiac conditions, LVEF was abnormal in only 1.9%, but LV GLS was abnormal in 46% of the patients. CONCLUSIONS: Most post-COVID patients had normal LVEF at 4-18 weeks post diagnosis, but over half had abnormal LV GLS.

• Korean Circulation Journal
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• v.53 no.10
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• pp.693-707
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• 2023

Background and Objectives: Inherited arrhythmia (IA) is a more common cause of sudden cardiac death in Asian population, but little is known about the genetic background of Asian IA probands. We aimed to investigate the clinical characteristics and analyze the genetic underpinnings of IA in a Korean cohort. Methods: This study was conducted in a multicenter cohort of the Korean IA Registry from 2014 to 2017. Genetic testing was performed using a next-generation sequencing panel including 174 causative genes of cardiovascular disease. Results: Among the 265 IA probands, idiopathic ventricular fibrillation (IVF) and Brugada Syndrome (BrS) was the most prevalent diseases (96 and 95 cases respectively), followed by long QT syndrome (LQTS, n=54). Two-hundred-sixteen probands underwent genetic testing, and 69 probands (31.9%) were detected with genetic variant, with yield of pathogenic or likely pathogenic variant as 6.4%. Left ventricular ejection fraction was significantly lower in genotype positive probands (54.7±11.3 vs. 59.3±9.2%, p=0.005). IVF probands showed highest yield of positive genotype (54.0%), followed by LQTS (23.8%), and BrS (19.5%). Conclusions: There were significant differences in clinical characteristics and genetic yields among BrS, LQTS, and IVF. Genetic testing did not provide better yield for BrS and LQTS. On the other hand, in IVF, genetic testing using multiple gene panel might enable the molecular diagnosis of concealed genotype, which may alter future clinical diagnosis and management strategies.

• Journal of Chest Surgery
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• v.36 no.6
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• pp.451-455
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• 2003

In August 2000, the American Heart Association and the European Resuscitation Council published the conclusions of tile International Guidelines 2000 Conference on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care which contains both the new recommendations and an in-depth review. The most important changes in the recommendations according to the authors are discontinuation of the pulse-check for lay people, 500 ml instead of 800∼1,200 ml tidal volume during bag-valve-mask ventilation (FiO2 > 0.4) of a patient with an unprotected airway, unifying correct endotracheal intubation size as 8.0 mm, vasopressin (40 units) and epinephrine (1 mg) as comparable drugs to treat patients with ventricular fibrillation, early prehospital survey and intravenous lysis for patients who have suffered coronary artery syndrome and stroke.

• Journal of Chest Surgery
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• v.12 no.4
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• pp.442-449
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• 1979

Although anoxic cardiac arrest produces a dry, quiet field, the ability of the myocardium to withstand the anoxic insult is uncertain. The current growth of interest in the use of various cardioplegic solutions ` has resulted in the development of a number of different solutions. In this study, 51 consecutive cases of elective open heart surgery with the aid of extracorporeal circulation were reviewed retrospectively to compare two methods of myocardial preservation. All of these open heart operations had been performed, using hemodilution principle under the moderate hypothermia at the Department of Thoracic and Cardiovascular Surgery, College of Medicine, Kyungpook National University from December, 1975 to July, 1979. In the 31 consecutive cases that form the anoxic arrest group, the operations were done with intermittent aortic cross-clamping and topical cardiac hypothermia. The heart was cooled topically by cold normal saline, which was converted to ice slush before application to the pericardial sac. Twenty of 51 consecutive cases were assigned to the cold cardioplegic method [the cardioplegic group], in which two kinds of cold cardioplegic solutions [Young solution and G IK solution] were infused into the aortic root proximal to the aortic cross clamp for myocardial preservation. Mean total aortic cross clamp times were 43 minutes in the anoxic arrest group and 67 minutes in the cardioplegic group. In the post-operative period, spontaneous regular heart beatings were recovered in 80 percent of the cardioplegic group as opposed to 25.7 percent of the anoxic arrest group. Ventricular fibrillation requiring DC shock was seen in 32.3 percent of the anoxic arrest group and 10 percent of the cardioplegic group. In the cardioplegic group, mean CPK-MB was one positive value on the first post-operative day, and mean LDH 1 was elevated to 51 0 units/ml on the 2nd post-operative day. These results indicate that protecting the myocardium with cold cardioplegia is superior to use of the anoxic cardiac arrest.

• Korean Journal of Veterinary Service
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• v.40 no.4
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• pp.287-292
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• 2017

A five-year-old, male, Great Dane weighing 107 kg was presented with anorexia, abdominal distension, and dyspnea for 5 days. Physical examination, blood works, radiography, electrocardiography (ECG), and echocardiography were performed. Based on severely low fractional shortening (FS) and marked four chamber enlargement in echocardiography, continuous atrial fibrillation and occasional ventricular premature complex (VPC) on ECG, the dog was diagnosed as dilated cardiomyopathy (DCM) concurrent with congestive heart failure. Pleural effusion and ascites were modified transudate. In accordance with DCM scoring system recommended by European Society of Veterinary Cardiology (ESVC), DCM score was 13/15 in this case. Concentrations of cTnI and NT-pro-BNP were 1.0 ng/mL and 693 pmol/L, respectively. Since the former and the latter were remarkably high values, it was certain that the patient had grave prognosis. Intensive care was performed for the dog and the clinical signs as well as the radiographic abnormalities were resolved. However, when he presented serious dyspnea again at 25 days post therapy, the dog was dead. In case of canine DCM, the scoring system for the diagnosis and cardiac biomarkers including NT-pro-BNP and cTnI could be useful to advise owners on the status and prognosis of their dog with DCM.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.665-671
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• 2017

Iks 칼륨 전류에 관여하는 KCNQ1유전자의 S140G 돌연변이는 심방세동에 영향을 미치는 대표적인 돌연변이 유전자로, 심방세동과 S140G 돌연변이의 상관관계를 밝히기 위한 연구들이 많이 진행되어 왔다. 하지만 S140G 돌연변이 유전자가 심방 세동 환자의 심실 반응에 영향을 미칠 수 있다는 선행연구를 비롯하여 심방과 심실의 활동전위에 영향을 미칠 수 있는 가능성이 있음에도 불구하고, KCNQ1 S140G 돌연변이 유전자의 심실세동에 대한 영향과 그 메커니즘에 대한 연구는 부족하다. 따라서 본 연구는 KCNQ1 S140G 돌연변이 유전자가 심실세동에 미치는 영향에 대한 컴퓨터 시뮬레이션 연구를 통해 그 상관관계를 밝히고자 하였다. 이를 위해 1차원 세포 모델을 비롯하여 2차원 심실세동 반응과 3차원 전기 생리학 및 기계적 수축 시뮬레이션을 진행하였다. 3차원의 전기생리학 및 기계적 수축 시뮬레이션에서는 심실의 박출 활동을 확인하기 위한 정상 박동 시뮬레이션과 심실 세동 발생시의 심실의 변화를 확인하기 위한 세동 시뮬레이션을 각각 진행하였다. 그 결과 KCNQ1 S140G 돌연변이로 인해 심실의 Iks가 증가되었으며, 그로 인해 심실의 활동 전위기간(APD)과 불응기(ERP)가 단축되는 것을 확인할 수 있었다. 또한 활동전위 지속 곡선(APDr)과 불응기 지속 곡선(ERPr)이 완만하게 나타났으며, 심근세포의 전도파장이 감소하였다. 3차원 정상 박동 시뮬레이션의 결과 표준형에서 보다 KCNQ1 S140G 돌연변이형에서 심실이 소모하는 ATP의 양과 박출계수가 감소하였다. 3차원 세동 시뮬레이션 결과 표준형에서는 심실세동이 종결되었으나, S140G 돌연변이 형에서는 심실세동이 종결되지않고 유지되었으며, 심실세동이 빠르게 발생하였다. 결론적으로, KCNQ1 S140G 돌연변이로 인해 증가된 심실의 Iks는 심실의 박출 효율을 감소시키고 심실세동을 발생시키고 유지시키며, 부정맥 발생의 위험성을 높일 수 있다.