• Journal of Biomedical Engineering Research
• /
• v.23 no.1
• /
• pp.1-8
• /
• 2002

Atrial fibrillation(AF). chronic or paroxysmal is the most frequent arrhythmia in human subjects Duration of P wave in signal-averaged electrocardiography(SAECG) reflects intra-atrial conduction time and therefore. could be used as an electrophysiological marker for atrial conduction chance at the earthy stave. So we apply the analysis method using SAECG to diagnose Paroxysmal atrial fibrillation(PAF) . Subjects Participated for the study consisted of two groups: a control group(n=34) of normal healthy volunteers and a group of AF Patients(n=38) with a documented history of PAF but no other history of cardiac disease. We evaluated the effect of several filtering and determination methods to find the starting and ending feints of the P wavy on its duration. To increase the measurement reliability of P wave duration. the automatic detection method was proposed. Also. to increase the detection rate for PAF risk, the decision threshold value was optimized using receiver operation characteristics(ROC) curve. Results showed that the highest statistical difference (p〈0.001) of the P wane duration between controls and subjects was obtained at the Processing condition, using absolute threshold vague(8.75 $\mu N$) , a least mean square(LMS) high pass filter and 30 Hz cutoff frequency. The most outstanding difference(sensitivity 88 % specificity 64.4 %) between controls and subjects was obtained at the decision threshold value of 112 ms.

• Journal of Chest Surgery
• /
• v.36 no.7
• /
• pp.457-462
• /
• 2003

Background: Surgical results of the Fontan procedures in patients with a single ventricle have improved. As the perioperative mortality continues to decline and late outcome is forthcoming, attention is now being directed toward late complications of the Fontan procedures. We retrospectively analyzed our experience with reoperations after Fontan procedures. Material and Method: Between January 1988 and December 2002, 24 patients underwent reoperations after Fontan procedures. The median age at Fontan procedures and reoperation was 3.3 years and 9.2 years, respectively. Types of initial Fontan procedures were atriopulmonary connection (n＝11), lateral tunnel Fontan (n＝11), and extracardiac conduit Fontan (n＝2). Indications for reoperation included atrioventricular valve regurgitation (n＝7), atrial arrhythmia (n＝8), Fontan pathway stenosis (n＝7), residual right-to-left shunt (n＝5), etc. Result: Procedures performed at reoperation included atrioventricular valve replacement (n＝6), conversion to lateral tunnel Fontan (n＝5), conversion to extracardiac conduit Fontan (n＝3), cryoablation of arrhythmia circuit (n＝7), etc. There was no operative mortality. There were 2 late deaths. Mean follow-up duration was 2.7$\pm$2.1 years. All patients except two were in NYHA class I at the latest follow-up. Among 8 patients with preoperative atrial arrhythmia, postoperative conversion to normal sinus rhythm was achieved in 7 patients. Conclusion: Reoperations after Fontan procedures could be achieved with low mortality and morbidity. Reoperation may lead to clinical improvement in patients with specific target conditions such as atrioventricular valve regurgitation, refractory atrial arrhythmia, or Fontan pathway stenosis, especially in patients with previous atriopulmonary connection.

• Journal of Chest Surgery
• /
• v.29 no.4
• /
• pp.386-392
• /
• 1996

Preoperative and postoperative evaluation was done in 60 adult patients above 20 years of age among 152 patients, who had operation for the congenital atrial septal defect from January 1984 to June 1993 in the Department of Thoracic and Cardiovascular Surgery, Chonbuk National University Hospital. Anatomically, the secundum type defect was present In 58 cases and the other two were ostium primum type defect. The defect were closed directly in 45 cases and with patches in 15 cases. Preopera ive EKG findings revealed regular sinus rhythm in 81%, arrhythmia 19%, RVH 32%, RAD 30%, Postoperative findings were regular sinus rhythm in 76%, arrhythmia 24%, RVH 25%. RAD 25%. In hemodynamic data, the mean SPAP in patients over 40 years old was 41.91 $\pm$ 14.33mmHg compared to 31.46 $\pm$ 13.77 mmHg in patients under 40 years old, and the difference between the two groups was stastistically significant. And then the patients were classified into two groups (group A sinus group, and group B : arrhythmia group) according to their preoperative rhythm. The patients in group B were older, had greater value of mean SPAP and Rp/Rs. Mean Qp/qs was higher in group A. But the difference between two groups about the mean Qp/qs and Rp/Rs was not significant. Postoperative complications such as arrhythmia, pneumothorax or hemothorax occurred in 7 cases, but there was no operative mortality. The functional improvement were remarkable in half of the patients who underwent surgery.

• Journal of Chest Surgery
• /
• v.41 no.3
• /
• pp.313-319
• /
• 2008

Background: The Cox maze-III procedure is considered as the most effective surgical treatment for atrial fibrillation. Because this procedure takes a long time and it complicates the concomitant cardiac surgery, some surgeons perform a left atrial maze procedure or pulmonary vein isolation only to reduce the operation time. This study was performed to evaluate how the modified procedures, with using cut-and-sew techniques, can influence the treatment of atrial fibrillation. Material and Method: Between Feb 1999 and June 2005, 40 patients (17 males and 23 females) with organic heart disease and atrial fibrillation underwent the Cox maze-III procedure (23), the left atrial maze procedure (10) or pulmonary vein isolation (7). The cut-an-sew technique was used to ablate the atrial wall, but cryoablation was used instead of the cut-and-sew technique for the coronary sinus and the inferior wall between the pulmonary vein and the mitral annulus. Result: After a mean follow-up period of $50.0{\pm}21.6$ months, all (100%) of the 23 patients who underwent the Cox maze-III procedure had regular sinus or atrial rhythm conversion, and 7(70%) of 10 with a left atrial maze procedure and 4(57.1%) of 7 with pulmonary vein isolation had regular sinus or atrial rhythm conversion (p=0.002). Conclusion: To obtain a high conversion rate from atrial fibrillation to a regular sinus rhythm or a regular atrial rhythm, the standard Cox maze-III procedure should be performed in both atria. The limited modified procedures like the left atrial maze procedure or pulmonary vein isolation may reduce the cure rate of atrial fibrillation.

• Journal of Chest Surgery
• /
• v.18 no.3
• /
• pp.446-455
• /
• 1985

A total and consecutive 156 patients have undergone cardiac valve surgery including 13 closed mitral commissurotomy, 13 open mitral commissurotomy, one mitral annuloplasty, 75 mitral valve replacement, one aortic annuloplasty, 24 aortic valve replacement, 3 tricuspid valve replacement, 25 double valve replacement and one triple valve replacement. 155 prosthetic valves were replaced in a period between September 1976 and August 1985. There were 68 males and 88 females with age range from 8 to 69 yrs [mean 36.5 yr]. Out of replaced valves, 61 was tissue valve including 54 Carpentier-Edwards, and 4 was mechanical valves including 74 St. Jude Medical, and the position replaced was 101 valves for mitral, 46 for aortic and 8 for tricuspid. Single valve replacement in 102 cases, double valve replacement in 25 cases [17 for AVR+MVR, and 8 for MVR+TVR], and only one case was noted in the triple valve replacement. Early mortality within 30 days after operation was noted in 11 cases [7%]; 7 after MVR, 2 after DVR, and each one after open mitral commissurotomy and mitral annuloplasty. Cause of death was valve thrombus, cerebral air embolism, low output syndrome, uncontrollable arrhythmia, parapneumonic sepsis, acute cardiac tamponade and left atrial rupture. 7 late deaths were noted during the follow-up period from 1 to 104 months [average 48 month]; three due to valve and left atrial thrombus formation, two due to CVA from overdose of warfarin, and each one due to congestive heart failure and chronic constrictive pericarditis, Anticoagulants after prosthetic valve replacement were maintained with warfarin, dipyridamole and aspirin to the level of around 50% of normal prothrombin time in 79 cases, and Ticlopidine with aspirin in 47 cases to compare the result of each group. There were 11 major thromboembolic episodes including 3 deaths in the warfarin group. Two cases of CVA due to overdose of warfarin was noted in the warfarin group. In the ticlopidine group, there was only one left atrial thrombus confirmed at the time of autopsy. Among the survived 138 cases, nearly all cases[136 cases] were included in NYHA functional class I and II during the follow-up period. In conclusion, surgical treatment of the cardiac valve disease in 156 clinical cases revealed excellent result with acceptable operative risk and late mortality. Prevention of thrombus formation with anti-platelet aggregator Ticlopidine has better result than warfarin group presently with no specific side effect such as bleeding or gastrointestinal trouble.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.12
• /
• pp.2655-2663
• /
• 2011

Several algorithms have been developed to detect AF which rely either on the form of P waves or the based on the time frequency domain analysis of RR variability. However, locating the P wave fiducial point is very difficult because of the low amplitude of the P wave and the corruption by noise. Also, the time frequency domain analysis of RR variability has disadvantage to get the details of irregular RR interval rhythm. In this study, we describe an atrial fibrillation detection algorithm through non-linear analysis of irregular RR interval rhythm based on the variability, randomness and complexity. We employ a new statistical techniques root mean squares of successive differences(RMSSD), turning points ratio(TPR) and sample entropy(SpEn). The detection algorithm was tested using the optimal threshold on two databases, namely the MIT-BIH Atrial Fibrillation Database and the Arrhythmia Database. We have achieved a high sensitivity(Se:94.5%), specificity(Sp:96.2%) and Se(89.8%), Sp(89.62%) respectively.

• Journal of Chest Surgery
• /
• v.25 no.3
• /
• pp.220-231
• /
• 1992

We have performed 28 single lung transplantation in mongrel dogs transplanting the left lung exclusively from November 1989 to September 1991, in the department of thoracic surgery of Seoul National University Hospital. In the donor dogs, the main pulmonary artery was divided proximal to its bifurcation, and the left atrium was incised freeing the left veins with a generous atrial cuff. We used cold saline in the first 7 transplantations and Euro-Collins or modified Euro-Collins solution in the remaining 17 transplantations as a lung preservatives. The bronchus was divided at two cartilage rings proximal to the upper lobe bronchus take off. In the recipient procedure, we used a Fogarty catheter as a bronchus block. Left atrial anastomosis was performed first using 5-O prolene and the pulmonary artery was anastomosed using 6-O prolene. The bronchus was anastomosed next with 4-O vicryl interruptedly and covered with a greater omentum which had been prepared previously. All dogs received cyclosporin A and azathioprine as immunosuppressants and were divided into two group. In the 10 Group I dogs, they survived within 6 days, mean survival time was 66.8$\pm$53.4 hours. In remainder 14 Group lI dogs, they survived above 6 days, mean survival time was 9. 5$\pm$5.6 days. The cause of death were as follows: 2 cases of sacrifice, 2 cases of respiratory insufficiency during operation, 2 cases of arrhythmia immediate postoperatively, 2 cases of bleeding, others in Group I, and 6 cases of sacrifice, 4 cases of sepsis, 3 cases of bleeding, others in Group lI. Results of bronchoscopic findings were obstruction above 50% in 12 cases of 16 performance cases within 5th day. Early chest radiologic haziness were showed, and total lung perfusion defect was frequently showed in both group within 7th day. Main autopsy findings were left atrial and pulmonary arterial thrombi and bronchial obstruction The major histologic findings of Group I were pleural exudate, hemorrhagic infarct, pulmonary congestion, and interesting histologic findings of Group II were 3 cases of perivascular or peribronchial lymphocyte infiltration, 3 cases of hemorrhage infarct, 2 cases of interstitial pneumonitis. The structual change of bronchioles, suggesting bronchiolitis obliterans was not observed due to improper preparation of proximal pulmonary tissue and short term survival times.

• Journal of Chest Surgery
• /
• v.46 no.2
• /
• pp.117-123
• /
• 2013

Background: We examined perioperative predictors of sustained sinus rhythm (SR) in patients undergoing the Cox maze operation and concomitant cardiac surgery for structural heart disease. Materials and Methods: From October 1999 to December 2008, 90 patients with atrial fibrillation (AF) underwent the Cox maze operation and other concomitant cardiac surgery. Eighty-nine patients, all except for one postoperative death, were followed-up with serial electrocardiographic studies, 24-hour Holter monitoring tests, and regular echocardiographic studies. Results: Eighty-nine patients undergoing the maze operation were divided into two groups according to the presence of SR. At the time of last follow-up (mean follow-up period, $51.0{\pm}30.8$ months), 79 patients (88.8%) showed SR (SR group) and 10 patients (11.2%) had recurrent AF (AF group). Factors predictive of sustained SR were the immediate postoperative conversion to SR (odds ratio, 97.2; p=0.001) and the presence of SR at the 6th month postoperatively (odds ratio, 155.7; p=0.002). Duration of AF, mitral valve surgery, number of valves undergoing surgery, left atrial dimension, and perioperative left ventricular dimensions and ejection fractions were not predictors of postoperative maintenance of SR. Conclusion: Immediate postoperative SR conversion and the presence of SR at the 6th postoperative month were independent predictors of sustained SR after the maze operation.

• Journal of Chest Surgery
• /
• v.53 no.3
• /
• pp.127-131
• /
• 2020

Background: This study was conducted to evaluate the safety and efficacy of left atrial appendage (LAA) excision using a vascular stapler. Methods: Fifty consecutive patients (mean age, 68±9 years) who underwent LAA excision using a vascular stapler during concomitant cardiac surgery were enrolled. In all patients, the excision site was evaluated using computed tomography at a median of 7 days (interquartile range, 5-13.3 days) postoperatively. The safety endpoint of this study was the occurrence of LAA excision-related events, which were defined as bleeding from the excision site that required reinforcement sutures or reoperation due to excision site bleeding. The efficacy endpoint was LAA excision failure, which was defined as a remnant LAA (a stump >1 cm in maximum length) or extravasation of radiocontrast dye. Results: LAAs were excised using 60- and 45-mm vascular staplers in 49 patients and 1 patient, respectively. Reinforcement sutures were needed in 4 patients due to staple-line bleeding and in 4 patients due to bleeding of the surrounding tissues. No patient underwent reoperation due to staple-related bleeding. A remnant LAA was observed in 2 patients, while extravasation of radiocontrast dye was not observed in any patients. Conclusion: LAA excision using a vascular stapler may be an effective technique for LAA exclusion. Delicate handling of the stapler device and LA tissue is required to prevent procedure-related complications.

• Journal of Chest Surgery
• /
• v.42 no.6
• /
• pp.710-718
• /
• 2009

Background: The Cox maze procedure has been used as a standard surgical treatment for atrial fibrillation for about 20 years. Recently, the creators have used a bipolar radiofrequency electrode (Cox maze IV procedure) instead of the incision and suture (cut-sew) technique to make atrial ablation lesions for persistent atrial fibrillation. We investigated clinical outcomes for the Cox maze procedure with a bipolar radiofrequency electrode and cryoablator in patients with persistent atrial fibrillation, and compared results with clinical outcomes of the cut-sew procedure. Material and Method: Between April 2005 and July 2007, 40 patients with persistent atrial fibrillation underwent Cox maze IV procedure with a bipolar radiofrequency electrode and cryoablator (bipolar radiofrequency group). Surgical outcomes were compared with those of 35 patients who had the cut-sew technique for the Cox maze III procedure. All patients had concomitant cardiac surgery. Postoperatively, the patients were followed up every 1 to 2 months. Result: At 6 months postoperatively, the conversion rate to regular sinus rhythm was not significantly different between the two groups: 95.0% for the bipolar radiofrequency ablation group; 97.1% for the cut-sew technique (p=1.0). At the end of the follow-up period, the conversion rate to regular sinus rhythm was also not significantly different (92.5% vs. 91.6%, p=1.0). In multivariate analysis using a Cox-regression model, the postoperative atrial dimension was an independent determinant of sinus conversion in the bipolar radiofrequency ablation group (hazard ratio 31, p=0.005). In the Cox-regression model for both groups, atrial fibrillation at 6 months postoperatively (hazard ratio 92.24, p=0.003) and the postoperative left atrial dimension (hazard ratio 16.05, p=0.019) were independent risk factors of continuance or recurrence of atrial fibrillation after Cox maze procedures. Aortic cross-clamp time and cardiopulmonary bypass time were significantly shorter in the radiofrequency group than in the cut-sew group. Conclusion: In the Cox maze procedure for patients with persistent atrial fibrillation, the use of bipolar radiofrequency ablation and a cryoablator is as good as the cut-sew technique for conversion to sinus rhythm. The postoperative left atrial dimension is an independent determinant of postoperative continuance and recurrence of atrial fibrillation.