• Korean Circulation Journal
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• 제53권11호
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• pp.758-771
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• 2023

Background and Objectives: Paroxysmal atrial fibrillation (AF) is a major potential cause of embolic stroke of undetermined source (ESUS). However, identifying AF remains challenging because it occurs sporadically. Deep learning could be used to identify hidden AF based on the sinus rhythm (SR) electrocardiogram (ECG). We combined known AF risk factors and developed a deep learning algorithm (DLA) for predicting AF to optimize diagnostic performance in ESUS patients. Methods: A DLA was developed to identify AF using SR 12-lead ECG with the database consisting of AF patients and non-AF patients. The accuracy of the DLA was validated in 221 ESUS patients who underwent insertable cardiac monitor (ICM) insertion to identify AF. Results: A total of 44,085 ECGs from 12,666 patient were used for developing the DLA. The internal validation of the DLA revealed 0.862 (95% confidence interval, 0.850-0.873) area under the curve (AUC) in the receiver operating curve analysis. In external validation data from 221 ESUS patients, the diagnostic accuracy of DLA and AUC were 0.811 and 0.827, respectively, and DLA outperformed conventional predictive models, including CHARGE-AF, C2HEST, and HATCH. The combined model, comprising atrial ectopic burden, left atrial diameter and the DLA, showed excellent performance in AF prediction with AUC of 0.906. Conclusions: The DLA accurately identified paroxysmal AF using 12-lead SR ECG in patients with ESUS and outperformed the conventional models. The DLA model along with the traditional AF risk factors could be a useful tool to identify paroxysmal AF in ESUS patients.

• Korean Circulation Journal
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• 제52권10호
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• pp.755-767
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• 2022

Background and Objectives: Cryoballoon catheter ablation for the treatment of patients with symptomatic atrial fibrillation (AF) has been adopted globally, but there are limited multicenter reports of 12-month outcomes in the Korean patient population. This analysis evaluated the clinical performance and safety of cryoballoon ablation (CBA) according to standard-of-care practices in Korea. Methods: This evaluation of Korean patients with AF was conducted within the larger Cryo Global Registry, which is a prospective, multicenter, post-market registry. Freedom from a ≥30-second recurrence of atrial arrhythmias (after a 90-day blanking period until 12 months) and procedural safety were examined in subjects treated with CBA at 3 Korean centers. Results: Overall, 299 patients with AF (60±11 years old, 24.7% female, 50.5% paroxysmal AF) underwent CBA using the Arctic Front Advance cryoballoon. Of those, 298 were followed-up for at least 12 months. Mean procedure-, left atrial dwell- and fluoroscopy time was 76±21 minutes, 56±23 minutes, and 27±23 minutes, respectively. Freedom from AF recurrence at 12 months was 83.9% (95% confidence interval [CI], 76.9-88.9%) in the paroxysmal and 61.6% (95% CI, 53.1-69.0%) in the persistent AF cohort. Rhythm monitoring was performed on average 4.7±1.4 times during the follow-up period. Serious device- or procedure-related adverse events occurred in 2 patients (0.7%). The 12-month Kaplan-Meier estimate of freedom from repeat ablation and cardiovascular-related hospitalization was 93.8% (95% CI, 90.4-96.1%) and 89.7% (95% CI, 85.6-92.7%), respectively. Conclusions: CBA is an efficient, effective, and safe procedure for the treatment of AF patients when used according to real-world practices in Korea.

• The Korean Journal of Physiology
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• 제18권1호
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• pp.19-35
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• 1984

Since the first report of Drury and $Szent-Gy{\ddot{o}}rgyi$ in 1929, the inhibitory influences of adenosine on the heart have repeatedly been described by many investigators. These studies have shown that adenosine and adenine nucleotides have overall depressant effects, similar to those of acetylcholine. Heart beats become slow and weak. It is also well known that adenosine is a potent endogenous coronary vasodilator. Many investigations on the working mechanisms of adenosine have been focused mainly on the effects of the coronary blood flow. However, the cellular mechanisms underlying the inhibitory action of adenosine on sinus node are not well understood yet. Thus, this study was undertaken to examine the behavior of rabbit SA node under influence of adenosine. In these series of experiments three kinds of preparations were used: whole atrial pair, left atrial strip, and isolated SA node preparations. The electrical activity of SA node was recorded with conventional glass microelectrodes 30 to 50 $M{\Omega}$. The preparations were superfused with bicarbonate-buffered Tyrode solution of pH 7.35 and aerated with a gas mixture of $3%\;CO_2-97%\;O_2$ at $35^{\circ}C$. In whole atrial pair, adenosine suppressed sinoatrial rhythm in a dose-dependent manner. Effect of adenosine on atrial rate appeared at the concentration of $10^{-5}M$ and was enhanced in parallel with the increase in adenosine concentration. Inhibitory action of adenosine on pacemaker activity was more prominent in the preparation pretreated with norepinephrine, which can steepen the slope of pacemaker potential by increasing permeability of $Ca^{+2}$. Calcium ions in perfusate slowly produced a marked change in sinoatrial rhythm. Elevation of the calcium concentration from 0.3 to 8 mM increased the atrial rate from 132 to 174 beats/min, but over 10 mM $Ca^{+2}$ decreased. The inhibitory effect of adenosine on sinoatrial rhythm developed very rapidly. Atrial rate was recovered promptly from the adenosine-induced suppression by the addition of norepinephrine, but extra $Ca^{+2}$ was less suitable to restore the suppression of atrial rate. Adenosine suppressed also atrial contractility in the same dosage range that restricted pacemaker activity, even in the reserpinized preparation. In isolated SA node preparation, spontaneous firing rate of SA node at $35^{\circ}C$(mean{\pm}SEM, n=16) was $154{\pm}3.3\;beats/min. The parameters of action potentials were: maximum diastolic potential(MDP), $-73{\pm}1.7\;mV: overshoot(OS), $9{\pm}1.4\;mV: slope of pacemaker potential(SPP), $94{\pm}3.0\;mV/sec. Adenosine suppressed the firing rate of SA node in a dose-dependent manner. This inhibitory effect appeared at the concentration of $10^{-6}M$ and was in parallel with the increase in adenosine concentration. Changes in action potential by adenosine were dose-dependent increase of MDP and decrease of SPP until $10^{-4}M$. Above this concentration, however, the amplitude of action potential decreased markedly due to the simultaneous decrease of both MDP and OS. All these effects of adenosine were not affected by pretreatment of atropine and propranolol. Lowering extra $Ca^{2+}$ irom 2 mM to 0.3 mM resulted in a marked decrease of OS and SPP, but almost no change of MDP. However, increase of perfusate $Ca^{2+}$ from 2 mM to 6 or 8 mM produced a prominent decrease of MDP and a slight increase of OS and SPP. Dipyridamole(DPM), which is known to block the adenosine transport across the cell membrane, definately potentiated the action of adenosine. The results of this experiment suggest that adenosine suppressed pacemaker activity and atrial contractility simultaneously and directly, by decreasing $Ca^{2+}-permeability$ of nodal and atrial cell membranes.

• Journal of Chest Surgery
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• 제32권3호
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• pp.255-261
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• 1999

배경: 심방세동은 모든 부정맥중에서 가장 흔하고 승모판질환을 가진 환자의 79%를 차지한다. 이 연구에서는 승모판 수술을 시행하는 환자의 심방세동이 냉동절제 없이 시행한 Maze 술식으로 제거되는지를 관찰하였다. 대상 및 방법: 1997년 5월에서 1998년 4월까지 승모판 질환과 심방세동이 있는 14명의 환자에서 냉동절제 없이 Maze III 술식을 시행하였다. 남자는 6례, 여자는 8례였고, 평균 나이는 46.2$\pm$10.7세 였다. 승모판막 협착증 11례, 그리고 승모판막 폐쇄부전 3례였다. 동반 질환으로 대동맥판막 질환 4례, 삼첨판막 폐쇄부전이 1례, 그리고 심방중격결손증이 2례였다. 경흉적 심초음파 검사상 좌심방의 평균 크기는 54.7$\pm$5.3 mm였고, 좌심방내에서 혈전이 관찰된 경우는 2례였다. 수술후 심초음파 검사상 승모판막을 통과하는 혈류를 측정함으로써 초기 충전파의 최고 속도와 심방수축파의 최고 속도 사이의 비(A/E ratio)를 계산하였다. 수술은 대동맥판막 치환술 4례, DeVega 판륜성형술 1례, 그리고 심방중격결손 폐쇄술 2례를 동반하여 승모판막 치환술을 13례에서 시행하였고, 나머지 1례는 Maze III 술식만 시행하였다. 결과: 5례(38%)의 경우에서 일시적인 심방세동이 재발하였고, 수술후 평균 38.8$\pm$23.5일에 flecainide 또는 amiodarone의 투여로 정상동방결절율동으로 전환되었다. 수술후 합병증은 일시적인 접합부율동 6례, 일시적인 심방세동 5례, 출혈로 인한 재수술 3례, , 술후 심막절개증후군 1례, 편측 성대마비 1례, 정신증 1례, 그리고 심근경색이 1례였다. 수술후 A/E비는 0.43$\pm$0.22였고, A파가 9(64%)례에서 양성이었다. 수술후 3개월에서 14개월(평균 추적관찰, 8.1개월)동안 14례에서 모두 정상 동방결절율동으로 전환되었고, 9례(64%)에서 좌심방의 수축을 관찰할수 있었으며, 11례(79%)에서는 항부정맥제를 투여하지 않고 있다. 결론: Maze III 술식에서 냉동절제를 시행하지 않더라도 승모판막 질환과 동반된 심방세동에 효과적인 수술임을 알 수 있었다.

• Journal of Chest Surgery
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• 제40권2호
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• pp.90-96
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• 2007

배경: 수술 후 심방 세동은 심장 수술과 관련된 흔한 합병증으로, 저자들은 심폐체외순환기를 사용하지 않고 시행하는 관상동맥우회술(Off-pump coronary artery bypass graft; OPCAB)과 심폐체외순환기를 사용하여 시행하는 관상동맥우회술(On-pump CABG)를 시행 받은 환자에서 수술 후 심방 세동의 발생률을 조사하여 심폐체외순환기 사용 여부가 수술 후 심방 세동 발생에 미치는 영향과 위험 인자에 대해 알아보고자 하였다. 대상 및 방법: 2002년 1월부터 2005년 12월까지 관상동맥우회술을 시행받은 306명의 환자 중 OPCAB을 시행 받은 178명과 On-pump CABG를 시행받은 69명을 대상으로 하였다. 두 군에서의 수술 후 심방 세동 발생률, 수술 전, 중, 후 위험 요인을 조사하였고, 각각 두 군에서의 수술 후 심방 세동의 위험 인자를 분석하였다. 결과: 수술 전 환자 변수에 관하여 두 군 사이에 차이가 없었다. 수술 후 심방 세동은 OPCAB군에서 25예(14%), On-pump CABG군에서 15예(21%)가 발생하였고, 두 군 사이에 통계적 차이는 없었다. 수술 후 심방 세동의 위험 인자로는 OPCAB 군에서는 65세 이상의 고연령, 수술 후 3일 동안의 총 수액 투입/배출의 불균형, 수술 후 3일 동안의 출혈량이, On-pump CABG군에서는 65세 이상의 고연령, 수술 후 3일 동안의 총 수액 투입/배출의 불균형이 단변량 분석에서 의미 있게 나타났으며, 다변량 분석에서는 두 군 모두에서 65세 이상의 고연령만이 수술 후 심방 세동의 위험 인자로 분석되었다. 결론 : 수술 후 심방 세동은 관상동맥우회술 후 생기는 흔한 합병증으로 OPCAB은 수술 후 심방 세동의 발생을 줄이지 않는 것으로 생각되며, 65세 이상의 고연령은 심폐체외순환기 사용 여부에 관계없이 수술 후 심방 세동 발생과 관련이 있음을 알 수 있었다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1991년도 춘계학술대회
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• pp.94-97
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• 1991

It is well known that multipoint and computerized intraoperative mapping systems improve the results of surgery for Wolff-Parkinson-White syndrome and show tremendous potential for opening an entirely new era of surgical intervention for the more common and lethal types of supraventricular tachyarrhythmias such as atrial flutter and atrial fibrillation. In addition, the ability to map and ablate the sometimes fleeting automatic atrial tachycardia is greatly enhanced by computerized mapping systems. In this study, we have developed 16 channel computerized data analysis system using microcomputer for basic research of electrophysiology and electrical propagation. This system is expected to enable us to study pathophysiology of cardiac arrhythmia and to improve the results of diagnosis and surgical treatment for cardiac arrhythmia.

• Journal of Chest Surgery
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• 제50권5호
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• pp.378-381
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• 2017

Patients with an atrial septal defect (ASD) and severe pulmonary arterial hypertension (PAH) are considered ineligible for defect closure surgery because of the risk of right ventricular decompensation and death after the operation. We report the case of a patient with large ASD and severe PAH who was able to undergo defect closure surgery successfully following long-term use of combined oral sildenafil and beraprost.

• Journal of Chest Surgery
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• 제23권1호
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• pp.41-48
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• 1990

Thirteen patients underwent repair of atrioventricular septal defect [AVSD] from January 1980 to July 1989 at Kyungpook National University Hospital. Two patients had complete AVSD [Rastelli type A] and eleven patients had partial AVSD [ostium primum atrial septal defect and cleft of anterior mitral leaflet]. In all the patients of partial AVSD, atrial septal defect was closed with Dacron patch and the mitral cleft was approximated with interrupted simple sutures. In one patient of complete AVSD, one patch technique was used to close the atrial and ventricular septal defect, and in the other patient of complete AVSD, two patch technique was used. In six patients, there were associated anomalies; four had isolated ostium secundum ASD, two had patent foramen ovale. Postoperative complete A-V block was noted in a patient of partial AVSD, but it was returned to 1st degree A-V block 30 months later and in another case of partial AVSD, severe congestive heart failure [NYHA functional class IV] due to residual mitral insufficiency was developed postoperatively, but this patient was recovered to the state of functional class I after receiving mitral valve replacement. There was one hospital death [8 %] resulting from low cardiac output.

• Journal of Chest Surgery
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• 제28권3호
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• pp.313-315
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• 1995

A 31-year-old man was admitted due to dyspnea on exertion[NYHA III-IV and general weakness.The echocardiographic findings reveal moderate secundum atrial septal defect and mitral stenosis.Mitral valve replaced through atrial septal defect and atrial septal defect closed by direct suture.Postoperative course was uneventful and discharged 2 weeks later.

• Journal of Chest Surgery
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• 제33권5호
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• pp.419-421
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• 2000

Noonan syndrome is characterized by typical facies, congenital heart defect, and some clinical features similar to Turner syndrome, but with normal chromosomes. The most commonly associated cardiac defects are pulmonary valvular stenosis and strial septal defect. We experienced a case of Nonan syndrome associated with pulmonay valve stenosis with double-chambered right ventricle and atrial septal defect and cryptorchidism. Pulmonary valvotomy was done through transannular incision. Hypertrophied muscle bundles were excised. Atrial septal defect was closed directly. RVOT was reconstructed with pericardial transannular patch. Orchiopexy was performed simultaneously without any problem.