• Journal of Chest Surgery
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• v.40 no.12
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• pp.811-816
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• 2007

Background: We analyzed our experience of arrhythmia surgery in patients with congenital heart disease. Material and Method: A retrospective review was performed on 43 consecutive patients with congenital heart disease, who underwent arrhythmia surgery between June 1998 and June 2006. Result: The median age at surgery was 52 years ($4{\sim}75$ years). The most frequent cardiac anomaly was an atrial septal defect (23/43, 53.5%). The types of arrhythmias were atrial flutter-fibrillation, intermittent non-sustainable ventricular tachycardia and others in 37, 2 and 4, respectively. Arrhythmia surgery consisted of a bi-atrial maze operation in 18 patients (modified cox maze III procedure in 5 patients, and a right side maze plus pulmonary vein cryo-isolation in 13), right side maze operation in 18 patients, cavo-tricuspid isthmus cryoablation for benign atrial flutter in 4 patients, right ventricular endocardial cryoablation in 2 patients and extranodal cryoablation for atrioventricular node re-entry tachycardia in 1 patient. The median follow-up was 23.8 months ($1{\sim}95.2$ months). There was no early mortality, and one late non-cardiac related death. The overall rates of restored sinus rhythm before discharge and $3{\sim}6$ months after surgery were 79% and 81%, respectively (bi-atrial maze group: 72% and 83%, right-side maze group: 77%, 77%). Conclusion: Arrhythmias associated with congenital heart disease can be safely treated surgically with an excellent intermediate-term outcome.

• Tuberculosis and Respiratory Diseases
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• v.45 no.1
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• pp.153-168
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• 1998

Background: The existing data indicate that obstructive sleep apnea syndrome contributes to the development of cardiovascular dysfunction such as systemic hypertension and cardiac arrhythmias, and the cardiovascular dysfunction has a major effect on high long-term mortality rate in obstructive sleep apnea syndrome patients. To a large extent the various studies have helped to clarify the pathophysiology of obstructive sleep apnea, but many basic questions still remain unanswered. Methods: In this study, the influence of obstructive sleep apnea on systemic blood pressure, cardiac rhythm and urinary catecholamines concentration was evaluated. Over-night polysomnography, 24-hour ambulatory blood pressure and ECG monitoring, and measurement of urinary catecholamines, norepinephrine (UNE) and epinephrine (UEP), during waking and sleep were undertaken in obstructive sleep apnea syndrome patients group (OSAS, n=29) and control group (Control, n=25). Results: 1) In OSAS and Control, UNE and UEP concentrations during sleep were significantly lower than during waking (P<0.01). In UNE concentrations during sleep, OSAS showed higher levels compare to Control (P<0.05). 2) In OSAS, there was a increasing tendency of the number of non-dipper of nocturnal blood pressure compare to Control (P=0.089). 3) In both group (n=54), mean systolic blood pressure during waking and sleep showed significant correlation with polysomnographic data including apnea index (AI), apnea-hypopnea index (AHI), arterial oxygen saturation nadir ($SaO_2$ nadir) and degree of oxygen desaturation (DOD). And UNE concentrations during sleep were correlated with AI, AHI, $SaO_2$ nadir, DOD and mean diastolic blood pressure during sleep. 4) In OSAS with AI>20 (n==14), there was a significant difference of heart rates before, during and after apneic events (P<0.01), and these changes of heart rates were correlated with the duration of apnea (P<0.01). The difference of heart rates between apneic and postapneic period (${\Delta}HR$) was significantly correlated with the difference of arterial oxygen saturation between before and after apneic event (${\Delta}SaO_2$) (r=0.223, P<0.001). 5) There was no significant difference in the incidence of cardiac arrhythmias between OSAS and Control In Control, the incidence of ventricular ectopy during sleep was significantly lower than during waking. But in OSAS, there was no difference between during waking and sleep. Conclusion : These results suggested that recurrent hypoxia and arousals from sleep in patients with obstructive sleep apnea syndrome may increase sympathetic nervous system activity, and recurrent hypoxia and increased sympathetic nervous system activity could contribute to the development of cardiovascular dysfunction including the changes of systemic blood pressure and cardiac function.

• Journal of Chest Surgery
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• v.16 no.4
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• pp.602-614
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• 1983

Six hundred fourteen consecutive cases of bioprosthetic cardiac valve replacement performed during the period from March 1976 through December 1982 were reviewed. A total of 748 tissue valves [534 Ionescu-Shiley valves, 144 Hancock valves, 46 Angell-Shiley, and 24 Carpentier-Edwards] were implanted in 610 patients. Of these, 477 had single valve replacements [403 mitral, 60 aortic, and 14 tricuspid] including three REDO MVR and one REDO AVR. The remaining 129 had double valve replacements [95 AVR and MVR and 34 MVR and TVR] and 8 had triple valve replacement.592 cases were evaluated. Overall early mortality rate [within 30 days of operation] was 7.1% [6.2% in single valve replacement, 10.2% in double valve replacement, and 16.7% in triple valve replacement]. Leading causes of mortality were low cardiac output or myocardial failure and ventricular arrhythmias. The follow-up period was from one month to 7 years with a cumulative follow-up of 906.6 patient-years [mean 1.53 years]. The late mortality was 1.6%, 3.9%, 0%, 2.6%, 6.6% and 2.0% per patient-year for MVR, AVR, TVR or triple valve replacement, AVR+MVR, MVR+TVR and total, respectively. Actuarial analysis of late results including early mortalities indicates an expected survival rate of 87.6+1.8% at 3 years and 85.92.4% at 7 years for all cases. We also analyzed actuarial survival rate between groups of each valve replacement [AVR, TVR, Double valve, and Triple valve] and the tissue valve groups in MVR. We experienced 7 cases [0.77% per patient-year] of confirmed endocarditis, two of which were fatal. Valve failure-free rates calculated according to the confirmed cases were 97.5% at 4 years, 87.5% at 7 years, and 88.3% at 6 years for Ionescu-Shiley, Hancock and Angell-Shiley valves, respectively. The occurrence rate of thromboembolism was 2.0% per patient-year in total cases, although almost all the patients were given anticoagulant therapy for one year. The occurring rate in MVR was 1.5% and 2.7% per patient-year for Ionescu-Shiley and Hancock valve groups, respectively. The difference in actuarial rate free from thromboemboli between Ionescu-Shiley and Hancock groups was statistically significant [P value less than 0.001]. Thromboembolic events beyond the period of anticoagulation therapy mainly occurred in patients with atrial fibrillation. The actuarial thromboemboli free survival was 95.71.4% at 3 years and 80.17.3% at 7 years. The incidence of hemorrhagic complications was 1.2% per patient-year [fatality 0.55% per patient-year] for anticoagulated patients. Although our clinical data favorably compares with results from other reports, our results suggest that anticoagulant therapy be given on a short-term basis or not at all to hemodynamically stable patients. Long-term therapy with antiplatelet drugs is probably inevitable with patients who have thromboembolic risk factors [such as atrial fibrillation].

• Journal of Chest Surgery
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• v.29 no.1
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• pp.1-6
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• 1996

We developed an experimental model of brain death using dogs. Brain death was induced by increasing the intracranial pressure (ICP) gradually by continuous Infusion of saline through an epidural Foley catheter in 5 mongrel dogs (weight, 18~22kg). Hemodynamic and electrocardiographic changes were evaluated continuously during the process of brain death and obtained the following results. 1. The average volume and time required to induce brain death was 4.8$\pm$1.0ml and 143.0$\pm$30.9minutes respectively. 2. There was a steady rise of the ICP after starting the constant infusion of saline, and ICP rised continuously until the brain death (122.0$\pm$62.5mmHg). After reaching to the maximal value (125.0$\pm$47.7mmHg) at 30 minutes after brain death, the ICP dropped and remained approximately constant at the slightly higher level than the mean arterial pressure (MAP). 3. MAP showed no change until the establishment of brain death and it declined gradually. The peak heart rate reached to 172.6$\pm$35.3/min at 30 minutes after the brain death. 4. Even though the body temperature and all hemodynamic variables, such as cardiac output, mean pulmonary arterial pressure, left ventricular (LV) end-diastolic pressure and LV maximum + dp/dt, were slightly greater than those of basal state, at the point of brain death, there was no statistically significant change during t e process of brain death. 5. There was no remarkable arrhythmias during the experiment except ventricular premature beats which was observed transiently in one dog at the time of brain death. Hemodynamic changes in the brain death model induced by gradual ICP increment were inconspicuous, and arrhythmias were rarely seen. Hyperdynamic state, which was observed at the point of brain death in another brain death model caused by abrupt ICP increase, was not observed.

• Journal of Chest Surgery
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• v.35 no.8
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• pp.594-598
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• 2002

Amiodarone is an iodinated benzofuran derivative that has been proved effective in the control of supraventricular and ventricular arrhythmias refractory to other antiarrhythmic drugs. In patients treated with amiodarone, subsequent surgical intervention is a common clinical scenario, but unfortunately we do not have definite data about complications due to amiodarone after cardiac surgery. Some reports have shown that amiodarone treatment can be associated with a state of $\alpha$-adrenergic and $\beta$-adrenergic receptor blockade, which requires more pacing and epinephrine infusion for perioperative hemodynamic support. And some reports have also identified a severe form of ARDS in patients on amiodarone therapy which was associated with siginificant morbidity and mortality. We exprienced a patient who expired after mitral valve replacement due to amiodarone-induced ARDS; therefore, we report this case with a brief literature.

• Journal of Chest Surgery
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• v.31 no.8
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• pp.770-775
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• 1998

Background: Atrial septal defect (ASD) is the most common congenital cardiac anomaly, accounting for 30 percent of congenital heart disease detected in the adult. Many patients with ASD are well tolerated and reach adult without significant symptoms. The patients with ASD die 4th and 5th decades, but prolonged survival is not uncommon. In general, the survival depends on whether pulmonary hypertension develops during adulthood or not. The most common cause of death in the patients with ASD is right ventricular failure or arrhythmias. Materials and methods: From January 1988 to June 1997, 33 cases of ASD underwent open heart surgeries in our hospital. Among them, 31 cases were adult ASD, and 2 tricuspid regurgitation, 1 pulmonic stenosis, 1 mitral regurgitation, 1 tricuspid regurgitation, and 1 coronary artery disease were combinded. All of the patients underwent surgical repair using autologus pericardial patch or direct closure. Results: The postoperative course was smooth and uneventful. Most of the patients showed significant improvement in ECG finding, hemodynamic profile, radiologic finding, and echocardiography, after surgery. Conclusions: Conclusively, most of the ASD should be closed even in patients over the age of 60 years, and early surgical repair must be done to prevent pulmonary hypertension, right ventricular failure, and arrythmias.

• Journal of Biomedical Engineering Research
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• v.38 no.6
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• pp.285-290
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• 2017

Radiofrequency catheter ablation is the interventional therapy that be employed to eliminate cardiac tissue caused by arrhythmias. During radiofrequency catheter ablation, The thrombus can occur at electrode tip if the temperature of tissue and electrode is excess $100^{\circ}C$. To prevent this phenomenon, we investigated numerical model of electrode for radiofrequency catheter ablation considering saline irrigation and temperature-controlled radiofrequency system. The numerical model is based on coupled electric-thermal-flow problem and solved by COMSOL Multiphysics software. The results of the models show that the dimensions of the thermal lesion are increased if the flow rate of the saline irrigation and the set temperature are increased. The surface width characterized to determine the thermal lesion isn't need to measure in temperature-controlled radiofrequency system due to convective heat transfer by saline irrigation at tissue-electrode interface.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.347-350
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• 2007

An ECG analysis with activity monitoring for the home care of elderly persons or patients, using wireless sensors technology was design and implemented. The changes in heart rate occur before, during, or following behavior such as posture changes, walking and running. Therefore, it is often very important to record heart rate along with posture and behavior, for continuously monitoring a patient's cardiovascular regulatory system during their daily life activity. The ECG and accelerometer data are continuously recorded with a built-in automatic alarm detection system, for giving early alarm signals even if the patient is unconscious or unaware of cardiac arrhythmias. The hardware allows data to be transmitted wirelessly from on-body sensors to a base station attached to server PC using IEEE802.15.4. If any abnormality un at server then the alarm condition sends to the doctor' PDA (Personal Digital Assistant).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2391-2398
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• 2009

Premature ventricular contractions are the most common of all arrhythmias and may cause more serious situation in some patients. Therefore, the detection of this arrhythmia becomes crucial in the early diagnosis and prevention of possible life threatening cardiac diseases. Most of the algorithms detecting PVC reported in literature is not always feasible due to the presence of noise and P wave making the detection difficult, and the process being time consuming and ineffective for real time analysis. To solve this problem, a new approach for the detection of PVC is presented based rhythm analysis and beat matching in this paper. For this purpose, the ECG signals are first processed by the usual preprocessing method and R wave was detected. The algorithm that decides beat type using the rhythm analysis of RR interval and beat matching of QRS width is developed. The performance of R wave and PVC detection is evaluated by using MIT-BIH arrhythmia database. The achieved scores indicate sensitivity of 99.74%, positive predictivity of 99.81% and sensitivity of 93.91%, positive predictivity of 96.48% accuracy respectively for R wave and PVC detection.

• 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.