• Journal of IKEEE
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• v.13 no.1
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• pp.77-86
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• 2009

A wavelet Electrocardiogram(ECG) detector and its analog-to-digital converter(ADC) for low-power implantable cardiac pacemakers are presented in this paper. The proposed wavelet-based ECG detector consists of a wavelet decomposer with wavelet filter banks, a QRS complex detector of hypothesis testing with wavelet-demodulated ECG signals, and a noise detector with zero-crossing points. To achieve high-detection performance with low-power consumption, the multi-scaled product algorithm and soft-threshold algorithm are efficiently exploited. To further reduce the power dissipation, a low-power ADC, which is based on a Successive Approximation Register(SAR) architecture with an on/off-time controlled comparator and passive sample and hold, is also presented. Our algorithmic and architectural level approaches are implemented and fabricated in standard $0.35{\mu}m$ CMOS technology. The testchip shows a good detection accuracy of 99.32% and very low-power consumption of $19.02{\mu}W$ with 3-V supply voltage.

• Journal of Biomedical Engineering Research
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• v.40 no.1
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• pp.32-37
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• 2019

In this study, we designed a blending algorithm for rate adaptive pacing for cardiac pacemaker. Generally, rate adaptive pacing (RAP) is applied to patients whose heart rate does not rise during exercise for chronotropic incompetence (CI) patient. It is very important to develop an algorithm for RAP that can be properly applied to CI patients. In order to design an RAP algorithm we used dual sensors. Firstly, we designed a bio-signal measurement system based on the dual sensors, which are accelerometer and respiratory system. Secondly, we conducted treadmill test for the simulation experiment while using 3-lead ECG as reference. Finally, we designed a blending algorithm based on activation state of the dual sensors. The proposed blending algorithm was subdivided into three sections based on the accelerometer signal, which are rapidly increased section (W1), hardly changed section (W2), and decreased section (W3). Each weight is set aside for each section. To evaluate this algorithm, ten healthy adult males were participated. The correlation and Root Mean Square Error between the proposed algorithm and the reference were compared, and shown to be r=0.88 and 2.82 bpm, respectively. These results show that the proposed blending algorithm of dual sensors enables proper tracking of the heart rate during exercise. Also, it shows the possibility that the proposed blending algorithm can be applied to improve quality of life of the chronotropic incompetence patient.

• The Journal of the Society of Stroke on Korean Medicine
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• v.23 no.1
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• pp.41-54
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• 2022

Brady-arrhythmia is defined as an arrhythmia in which the heart rate slows to less than 60 beats per minute. Brady-arrhythmia reduces cardiac output and causes changes in blood flow. As a result, dizziness occurs because not only ischemia occurs in the central nervous system, but also blood flow in major organs decreases. The insertion of an artificial pacemaker is known as almost the only treatment alternative for patients with brady-arrhythmia with symptoms. This study reports a case of 85 year old male diagnosed with brady-arrhythmia complaining presyncope type of dizziness. The patient underwent complex Korean medicine treatments by herbal medicine, acupuncture and moxibustion. The daily average value of pulse rate, K-DHI score, NRS score and the patient's subjective expression of symptoms were used as evaluation tools. This study suggested a significant improvement in symptoms through complex Korean medicine treatments without the use of anti-arrhythmic drugs or insertion of an artificial pacemaker in the patient with brady-arrhythmia complaining dizziness.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.281-288
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• 1979

For years, physicians and anatomists have been interested in the heart that has one functioning ventricle. Various terms have been suggested for this entity including single ventricle, common ventricle, double-inlet left ventricle, cor biatriatum triloculare, and primitive ventricle. In this report, the term "single ventricle" is utilized as suggested by Van Praagh, and is defined as that congenital cardiac anomaly in which a common or separate atrioventricular valves open into a ventricular chamber from which both great arterial trunks emerge. An outlet chamber, or infundibulum, may or may not be present and give rise to the origin of either of the great arteries. This definition excludes the entity of mitral and tricuspid atresia. An 11 year old cyanotic boy was admitted chief complaints of exertional dyspnea and frequent upper respiratory infection since 2 weeks after birth. He was diagnosed as inoperable cyanotic congenital heart disease, and remained without any corrective treatment up to his age of 11 year when he suffered from aggravation of symptoms and signs of congestive heart failure for 2 months before this admission. On 22nd of May 1979, he was admitted for total corrective operation under the impression of tricuspid atresia suggested by a pediatrician. Physical check revealed deep cyanosis with finger and toe clubbing, and grade V systolic ejection murmur with single second heart sound was audible at the left 3rd intercostal space. Development was moderate in height [135 cm] and weight[28Kg]. Routine lab findings were normal except increased hemoglobin [21.1gm%], hematocrit [64 %], and left axis deviation with left ventricular hypertrophy on EKG. Cardiac catheterization and angiography revealed 1-transposition of aorta, pulmonic valvular stenosis, double inlet of a single ventricle with d-loop, and normal atriovisceral relationship [Type III C solitus according to the classification of Van Praagh]. At operation, longitudinal incision at the outflow tract of right ventricle in between the right coronary artery and its branch [LAD from RCA] revealed high far anterior aortic valve which had fibrous continuity with mitral annulus, and pulmonic valve was stenotic up to 4 mm in diameter positioned posterolaterally to the aorta. Ventricular septum was totally defective, and one markedly hypertrophied moderator band originated from crista supraventricularis was connected down to the imaginary septum of the ventricular cavity as a pseudoseptum of the ventricle. Size of the defect was 3X3 cm2 in total. Patch closure of the defect with a Teflon felt of 3.5 x 4 cm2 was done with interrupted multiple sutures after cut off of the moderator band, which was resutured to the artificial septum after reconstruction of the ventricular septum. Pulmonic valvotomy was done from 4 mm to 11 mm in diameter thru another pulmonary arteriotomy incision, and right ventriculotomy wound was closed reconstructing the right ventricular outflow tract with pericardial autograft of 3 x 4 cm2. Atrial septal defect of 2 cm in diameter was closed with 3-0 Erdeck suture, and atrial wall was sutured also when rectal temperature reached from 24`C to 35.5`C. Complete A-V block was managed with temporary external pacemaker with a pacing rate of 110/min. thru myocardial wire, and arterial blood pressure of 80/50 mmHg was maintained with Isuprel or Dopamine dripping under the CVP of 25-cm saline. Consciousness was recovered one hour after the operation when his blood pressure reached 100 /70 mmHg, but vital signs were not stable, and bleeding from the pericardial drainage and complete anuria were persisted until his heart could not capture the pacemaker impulse, and patient died of low output syndrome 320 min after the operation.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.289-296
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• 1979

For years, physicians and anatomists have been interested in the heart that has one functioning ventricle. Various terms have been suggested for this entity including single ventricle, common ventricle, double-inlet left ventricle, cor biatriatum triloculare, and primitive ventricle. In this report, the term "single ventricle" is utilized as suggested by Van Praagh, and is defined as that congenital cardiac anomaly in which a common or separate atrioventricular valves open into a ventricular chamber from which both great arterial trunks emerge. An outlet chamber, or infundibulum, may or may not be present and give rise to the origin of either of the great arteries. This definition excludes the entity of mitral and tricuspid atresia. An 11 year old cyanotic boy was admitted chief complaints of exertional dyspnea and frequent upper respiratory infection since 2 weeks after birth. He was diagnosed as inoperable cyanotic congenital heart disease, and remained without any corrective treatment up to his age of 11 year when he suffered from aggravation of symptoms and signs of congestive heart failure for 2 months before this admission. On 22nd of May 1979, he was admitted for total corrective operation under the impression of tricuspid atresia suggested by a pediatrician. Physical check revealed deep cyanosis with finger and toe clubbing, and grade V systolic ejection murmur with single second heart sound was audible at the left 3rd intercostal space. Development was moderate in height [135 cm] and weight[28Kg]. Routine lab findings were normal except increased hemoglobin [21.1gm%], hematocrit [64 %], and left axis deviation with left ventricular hypertrophy on EKG. Cardiac catheterization and angiography revealed 1-transposition of aorta, pulmonic valvular stenosis, double inlet of a single ventricle with d-loop, and normal atriovisceral relationship [Type III C solitus according to the classification of Van Praagh]. At operation, longitudinal incision at the outflow tract of right ventricle in between the right coronary artery and its branch [LAD from RCA] revealed high far anterior aortic valve which had fibrous continuity with mitral annulus, and pulmonic valve was stenotic up to 4 mm in diameter positioned posterolaterally to the aorta. Ventricular septum was totally defective, and one markedly hypertrophied moderator band originated from crista supraventricularis was connected down to the imaginary septum of the ventricular cavity as a pseudoseptum of the ventricle. Size of the defect was 3X3 cm2 in total. Patch closure of the defect with a Teflon felt of 3.5 x 4 cm2 was done with interrupted multiple sutures after cut off of the moderator band, which was resutured to the artificial septum after reconstruction of the ventricular septum. Pulmonic valvotomy was done from 4 mm to 11 mm in diameter thru another pulmonary arteriotomy incision, and right ventriculotomy wound was closed reconstructing the right ventricular outflow tract with pericardial autograft of 3 x 4 cm2. Atrial septal defect of 2 cm in diameter was closed with 3-0 Erdeck suture, and atrial wall was sutured also when rectal temperature reached from 24`C to 35.5`C. Complete A-V block was managed with temporary external pacemaker with a pacing rate of 110/min. thru myocardial wire, and arterial blood pressure of 80/50 mmHg was maintained with Isuprel or Dopamine dripping under the CVP of 25-cm saline. Consciousness was recovered one hour after the operation when his blood pressure reached 100 /70 mmHg, but vital signs were not stable, and bleeding from the pericardial drainage and complete anuria were persisted until his heart could not capture the pacemaker impulse, and patient died of low output syndrome 320 min after the operation.

• The Korean Journal of Physiology
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• v.23 no.2
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• pp.339-350
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• 1989

Electrophysiological effects of ammonia was studied in the isolated superfused sinus node and atrial muscle cells of the rabbit heart. No significant changes were observed in the overshoot potential (05), maximum diastolic potential (MDP), and action potential amplitude (APA) of the sinus node cells following superfusion with 3.0 mM ammonia, fifty times upper limit of the normal human plasma level. However the action potential duration (APD) of sinus node cells were significantly prolonged after superfusion with 0.6 mM ammonia for 20 min or with 1.2 and 3.0 mM ammonia for 5 minutes. Ammonia in all the concentrations tested decreased the rate of spontaneous firing (RSF) from the sinus node cells. After superfusion of sinus node cells with 0.3 mM ammonia for 20 min, the RSF significantly decreased from 20 min to 25 min after onset of superfusion while a significant decrement in the RSF was observed from 7 min to 30 min following superfusion with 3.0 mM ammonia for S min. On the other hand, the effects of ammonia on the action potential of the rabbit atrial muscle cell were much similar to those on pacemaker cells except that the atrial cell was generally less sensitive to ammonia. The results suggest that ammonia may cause changes in the action potential of the rabbit cardiac cells by the direct action, and that the cardiac effects of ammonia are generally opposite to those of glycine.

• Journal of Chest Surgery
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• v.18 no.4
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• pp.635-642
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• 1985

Double outlet left ventricle [DOLV] is a rare cardiac anomaly in which both great arteries arise entirely, or predominantly above the morphologically left ventricle. About 100 cases of DOLV have been reported in the literatures by 1984. We have experienced eight cases of DOLV at Seoul National University Hospital during the period from October 1981 to July 1905. Ages of the patients were ranged from 12 months to 24 years old, and chief complaints on admission were frequent URI and DOE in 5 cases and cyanosis in other 3 cases. In all eight patients, Cardiac catheterization and cineangiography were performed but pre-operative diagnoses were incorrect except one case [VSD in 2 cases, DORV in 2cases, c-TGA in 2 cases and TOF in one case] We have performed total corrective surgery in seven patients. In case I, patch closure of VSD aligning aorta and pulmonary artery with LV, ligation of proximal pulmonary artery and the use of external valved conduit from RV to PA have been employed. In other 6 cases, intraventricular repair using boomerang shaped Dacron patch with correction of associated anomalies were employed. In remaining one patient who had coexistent PDA and coarctation of aorta, we have performed coarctoplasty and PDA ligation initially and the patient is waiting for subsequent total corrective procedure. In seven patients whom we have performed total corrective surgery, there is one hospital mortality due to right heart failure and one complication of complete heart block necessitating permanent pacemaker implantation. All survivors are doing well in follow up period of 9 months to 4 years. To our knowledge, this is the first report of surgical experiences for DOLV in the Korean literature.

• Journal of Chest Surgery
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• v.18 no.1
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• pp.1-6
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• 1985

Isolated sinus node cells of the rabbit were used to assess the effects of extracellular Na, K, Ca and Mg concentrations on cardiac pacemaker activity. With intracellular glass micro-electrodes spontaneous action potentials of SA node were recorded and the effects of various ions and their blockers were analyzed in terms of the cycle length, the amplitude and the duration of action potentials, the results obtained were as follows. 1. Sodium reduction [up to 30%] decreased the amplitude of action potential and lengthened the cycle length. TTX, specific blocker of Na channel slightly lengthened the cycle length. 2. Increasing potassium ion concentration, the duration of action potential decreased and the frequency increased in 6mM, however, spontaneous action potential was stopped in 24 mM. Barium ion known to be decreasing K conductance increased the duration of action potential but no significant change in the cycle length was noticed. 3. Calcium ion has shortening effect on the duration and the cycle length of action potential but not with dose-dependent manner. Cadmium ion .[0.02mM] lengthened cycle length and the duration of action potential. 4. Increasing the concentration of magnesium ion the cycle length was lengthened, significantly.

• Journal of Korean Critical Care Nursing
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• v.3 no.2
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• pp.49-59
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• 2010

Purpose: The purpose of this study was to investigate in-service education needs in order to develop clinical competence of critical care nurses', and to identify contents which have to include in-service education according to nurses' characteristics. Methods: Data was collected using Critical Care Nurse Job Analysis Tool that was modified by professional team. Collected data was analyzed using the SPSS program. Results: Total 148 critical care nurses, who had worked at adult intensive care unit of one tertiary hospital in Seoul, filled out questionnaire. The results showed the participants highly needed education about cardiological nursing practices such as ECMO, pacemaker, cardiac tamponade. And there were significant correlations among in-service educational needs and ICU careers, preceptors experience, and charge nurse experience. Conclusion: It will be necessary for better nursing to develop in-service education is based on critical care nurse's need and their characteristics. Especially, it is important to develop and provide in-service education programs, which consider ICU nurse's differences for their career ladder and nursing preceptors.

• Neonatal Medicine
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• v.18 no.2
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• pp.395-398
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• 2011

Sick sinus syndrome (SSS) is a disorder characterized by sinus node dysfunction. Although the condition is most common in the elderly, it can occur in children including neonates and its recognition and treatment are important. The diagnosis of SSS is based on the presence of sinus bradycardia, sinus arrest or exit block, combinations of sinoatrial and atrioventricular nodal conduction disturbances, and atrial tachyarrhythmias documented in the Holter recordings. In most children with SSS, previous history of congenital heart malformation or cardiac surgery is noted. SSS is also seen in the children including neonates without heart disease or other contributing factors, however SSS is most often idiopathic. The treatment of SSS depends on the basic rhythm problem, but generally involves the placement of a cardiac pacemaker. We report a case of SSS in extremely low birth weight infant without congenital heart disease and suggest that the treatment system is necessary for preterm infants with SSS.