• Journal of Yeungnam Medical Science
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• v.24 no.2
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• pp.197-205
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• 2007

Background : The occurrence of atrial fibrillation after ablation of atrial flutter is clinically important. We investigated variables predicting this evolution in ablated patients without a previous atrial fibrillation history. Materials and Methods : Thirty-six patients (Male=28) who were diagnosed as atrial flutter without previous atrial fibrillation history were enrolled in this study. Group 1 (n=11) was defined as those who developed atrial fibrillation after atrial flutter ablation during 1 year follow-up. Group 2 (n=25) was defined as those who has not occurred atrial fibrillation during same follow-up term. Echocardiogram was performed to all patients. We measured left atrial size, left ventricle end diastolic and systolic dimension, ejection fraction and left atrial volume index before and after ablation of atrial flutter. The differences of each variables were compared and analyzed between two groups. Results : The preablation left ventricular ejection fraction (preLVEF) and postablation left ventricular ejection fraction (postLVEF) are $54{\pm}14%$, $56{\pm}13%$ in group 1 and $47{\pm}16%$, $52{\pm}13%$ in group 2. The differences between each two groups are statistically insignificant ($2.2{\pm}1.5$ in group 1 vs $5.4{\pm}9.8$ in group 2, p=0.53). The preablation left atrial size (preLA) and postablation left atrial size (postLA) are $40{\pm}4mm$, $41{\pm}4mm$ in group1 and $44{\pm}8mm$, $41{\pm}4mm$ in group 2. The atrial sizes of both groups were increased but, the differences of left atrial size between two groups before and after flutter ablation were statistically insignificant ($0.6{\pm}0.9mm$ in group 1 vs $-3.8{\pm}7.4mm$ in group 2, p=0.149). The left atrial volume index before flutter ablation was significantly reduced in group 1 than group 2 ($32{\pm}10mm^3/m^2$, $35{\pm}10mm^3/m^2$ in group 1 and $32{\pm}10mm^3/m^2$, $29{\pm}8mm^3/m^2$ in group 2, p<0.05). Conclusion : The difference between left atrial volume index before and after atrial flutter ablation is the robust predictor of occurrence of atrial fibrillation after atrial flutter ablation without previous atrial fibrillation.

• Journal of Veterinary Clinics
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• v.27 no.4
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• pp.435-439
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• 2010

A six-year-old intact female Bull Terrier dog (weighing 17 kg) was referred to the Veterinary Teaching Hospital with exercise intolerance and occasional syncope as the primary complaint. Diagnostic studies revealed a rare case of atrial flutter with complete heart block and aberrant ventricular activation from the ectopic focus, possibly due to idiopathic dilated cardiomyopathy. Although the dog was responded with cardiac medication for right-sided heart failure and anti-arrhythmic agent (dofetilide), the dog died suddenly of cardiac arrest after 11 months of treatment.

• Journal of Chest Surgery
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• v.48 no.1
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• pp.67-69
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• 2015

This is a report of a biatrial cardiac myxoma in a young man with a 10-month history of exertional dyspnea and palpitation. The echocardiogram revealed biatrial myxoma prolapsing through the mitral and tricuspid valves during diastole. All cardiac chambers were enlarged and dysfunctional. The electrocardiogram revealed a rapid ventricular response with atrial flutter rhythm. The masses were resected and diagnosed as myxoma by a histological examination. The follow-up echocardiogram revealed significant improvement in ventricular function and reduction in the cardiac chambers' volume. There was no evidence of myxoma recurrence. The most probable cause of the patient's heart failure was considered to be tachycardia-induced cardiomyopathy.

• Journal of Chest Surgery
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• v.14 no.1
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• pp.49-59
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• 1981

This is one case report of surgically treated partial atrioventricular canal. The 22 year-old male patient had no definitive history of frequent respiratory infection and cyanosis in his early childhood. Since his age of 7 years, dyspnea was manifested on exertion. First appearance of congestive heart failure was at his age of 16 years old. The physical examination revealed that the neck veins were distended and heaving of precordium. A thrill was palpable on the left 3rd-4th intercostal space extending from the sternal border toward the apex and Grade IV/VI systolic ejection murmur was audible on it. Neither cyanosis nor clubbing was noted. Liver was palpable about 5 finger breadths. Chest X-ray revealed increased pulmonary vascularity and severe cardiomegaly (C-T ratio = 74%). EKG revealed LAD, clockwise rotation, LVH and trifascicular block. Echocardiogram showed paradoxical ventricular septal movement, narrowed left ventricular outflow tract and abnormal diastolic movement of the anterior leaflet of mitral valve. Right heart catheterization resulted in large left to right shunt (Qp : Qs = 5.7: 1), ASD and moderate pulfllonary hypertension. Finally, left ventriculogram revealed typical goose neck appearance of left ventrlcalar outflow tract. On Oct. 10, 1980, open heart surgery was performed. Operative findings were: 1. Large primum defect ($6{\times}5$ Cm in diameter) 2. Cleft on the anterior leaflet of mitral valve. 3. The upper portion of ventricular septum was descent but no interventricular communication. 4. Downward attachment of the atrioventricular valves on the ventricular muscular septum. 5. Medium sized secumdum defect ($2{\times}1$ Cm in diameter). The cleft was repaired with 4 interrupted sutures. The primum defect was closed with Teflon patch and the secundum defect was closed with direct suture closure. Postoperatively atrial flutter-fibrillation in EKG and Grade U/VI apical systolic murmur were found. The postoperative course was uneventful and discharged on 29th postoperative day in good general conditions.

• Industrial Engineering and Management Systems
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• v.12 no.4
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• pp.380-388
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• 2013

Large variation in electrocardiogram (ECG) waveforms continues to present challenges in defining R-wave locations in ECG signals. This research presents a procedure to extract the R-wave locations by forward-backward (FB) algorithm and classify the arrhythmic beat conditions by using RR intervals. The FB algorithm shows forward and backward searching rules from QRS onset and eliminates lower-amplitude signals near the baseline using a statistical process control concept. The proposed algorithm was trained the optimal parameters by using MIT-BIH arrhythmia database (MITDB), and it was verified by actual Holter ECG signals from a local hospital. The signals are classified into normal (N) and three arrhythmia beat types including premature ventricular contraction (PVC), ventricular flutter/fibrillation (VF), and second-degree heart block (BII) beat. This work produces 98.54% accuracy in the detection of R-wave location; 98.68% for N beats; 91.17% for PVC beats; and 87.2% for VF beats in the collected Holter ECG signals, and the results are better than what are reported in literature.

• Journal of Chest Surgery
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• v.25 no.6
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• pp.672-677
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• 1992

This is a clinical review of the results from electric cardioversion and pharmacological therapy used in our hospital for reverting cardiac arrythmia in patients with mitral valve surgery between Jan. 1990 and Jun. 1991. Of 62 evaluated patients, 16 patients had regular sinus rhythm and the other 46 had arrhythmias [42; atrial fibrillation 1; atrial flutter 1; premature ventricular contraction] preoperatively. In 2 of patients with sinus rhythm, atrial fibrillation newly developed after surgery and was converted into sinus rhythm soon by intravenous administration of digoxin. Remaining 14 patient resumed sinus rhythm spontaneously. In patients with preoperative arrythmia, 3 patients reverted into sinus rhythm from atrial fibrillation by electric cardioversion at operative field, 1 patient by lidocain and mexiletine, 4 patients by combined use of digoxin and verapamil, 4 patients by 2 times of oral quinidine and 9 patient by long term use of oral amiodarone. Throughout this consecutive trials of anti-arrhythmic drugs and electric cardioversion, Conversion into normal sinus rhythm occurred in 48% of patients with arrhythmia developed after mitral valve surgery.

• Journal of Mechanical Science and Technology
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• v.15 no.5
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• pp.613-622
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• 2001

Interaction of blood flow and leaflet behavior in a bileaflet mechanical heart valve was investigated using computational analysis. Blood flows of a Newtonian fluid and a non-Newtonian fluid with Carreau model were modeled as pulsatile, laminar, and incompressible. A finite volume computational fluid dynamics code and a finite element structure dynamics code were used concurrently to solve the flow and structure equations, respectively, where the two equations were strongly coupled. Physiologic ventricular and aortic pressure waveforms were used as flow boundary conditions. Flow fields, leaflet behaviors, and shear stresses with time were obtained for Newtonian and non-Newtonian fluid cases. At the fully opened phase three jets through the leaflets were found and large vortices were present in the sinus area. At the very final stage of the closing phase, the angular velocity of the leaflet was enormously large. Large shear stress was found on leaflet tips and in the orifice region between two leaflets at the final stage of closing phase. This method using fluid-structure interaction turned out to be a useful tool to analyze the different designs of existing and future bileaflet valves.

• 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.

• Journal of Chest Surgery
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• v.31 no.4
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• pp.393-397
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• 1998

A 25-year-old man with viral cardiomyopathy and chronic active hepatitis successfully underwent dynamic cardiomyoplasty for the first time in Korea on July 30, 1996. The patient had been intermittently dyspneic for 5 years and was admitted to our center twice because of heart failure. For the past 2 years, he was NYHA functional class III status with a left ventricular ejection fraction(LVEF) of around 30%. The patient was born with scoliosis and showed a short stature. The liver function showed elevated liver enzymes, and hepatitis B antigen was positive. The liver biopsy revealed chronic active hepatitis. The preoperative echocardiogram showed decreased left ventricular function with grade II mitral and grade II tricuspid regurgitation with dilated left and right atrium. Recently his symptoms worsened and we decided to perform a dynamic cardiomyoplasty. The left latissmus dorsi muscle(LDM) was mobilized and tested with lead placement on his right lateral decubitus position. The patient was positioned into supine and, after median sternotomy, the heart was wrapped with the mobilized muscle. The Russian made cardiomyostimulator(EKS-445) and leads (Myocardial PEMB for heart and PEMP-1 for LDM) were used. The total operation time was 8 hours and there were no perioperative episodes. Postoperatively the LDM had been trained for a 10 week period and currently the stimulation ratio is maintained at 1:4. The postoperative LVEF did not increase with the value of 30-35%. However, the patient feels better postoperatively with slightly increased activity.

• 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.