• Journal of Chest Surgery
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• v.39 no.9 s.266
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• pp.681-691
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• 2006

Background: The aim of this study was to investigate the mid-term outcomes of our modifications to the maze procedure using cryoablation for treating atrial fibrillation associated with rheumatic mitral valve disease. Material and Method: Between March 2000 and February 2004, 177 consecutive patients underwent the modified maze procedure with the use of cryoablation concomitant with mitral valve surgery for atrial fibrillation associated with rheumatic mitral valve disease, and were divided into three groups: (1) modified Cox-maze III (CM group, n=88): (2) modified Kosakai-maze (KM group, n=63): and (3) left atrial maze procedure (LA group, n=26). The postoperative and follow-up results were analyzed and compared between the groups. Result: There were three hospital deaths (1.7%) and no significant differences in the incidence of postoperative complications between the three groups. The operative time, such as the cardiopulmonary bypass and aortic crossclamp time, were significantly longer in the CM group than in the KM and LA groups, respectively (p<0.0001). The mean follow-up was $22.4{\pm}15.1$ months ($1\sim52.6$ months) for all patients. One late death developed in the CM group (0.0%). At last follow-up, 139 patients exhibited sinus rhythm (79.9%), which was also regained in 67 patients (77.9%) in the CM group, 50 (80.7%) in the KM group and 22 (84.6%) in the LA group (p=0.743). The actuarial freedom from stroke at 4 years was $84.5{\pm}9.4%$ in the CM group, $95.0{\pm}4.9%$ in the KM group, and $92.9{\pm}6.9%$ in the LA group (p=0.916). Conclusion: The modified maze procedure using cryoablation is safe and effective in treating chronic atrial fibrillation associated with rheumatic mitral valve disease.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.193-204
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• 1998

The single crystal of the $LiTaO_3$has large electro-optic effects, so it is applied to optical switch, acousto-optic deflector, and optical memory device as hologram using photorefractive effect. In this study, optic-grade undoped $LiTaO_3$and Fe:LiTaO$LiTaO_3$single crystals were grown by the Czochralski method and optical transmission and absorption spectrums were measured in the wavelength of UV-VIS range. The curie temperature was determined with DSC and by measuring capacitance for the grown undoped crystal and ceramic powder samples of various Li/Ta ratio. In case of having a 48.6 mol% $Li_2O$ as a starting Li/Ta ratio, the results of concentration variations were below 0.01 mol% $Li_2O$ all over the crystal, so it was confirmed that $LiTaO_3$single crystals were grown under congruent melting composition having optical homogeneity. The curie temperature of the Fe:$LiTaO_3$crystal was increased with increased with increased doped Fe concentrations;by the ratio of $7.5^{\circ}C$ increase per Fe 0.1 wt%. Also, the optical transmittance was about 78 %, which was sufficient for optical device.

• Journal of Chest Surgery
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• v.30 no.3
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• pp.287-292
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• 1997

.Itrial fibrillation is one of the most common cardiac arrhythmias requiring treatment. About 60% of patients with mitral valvular disease have atrial fibrillation and one third of patients with atrial fibrillation may have the past history of thromboembolic events. Between April 1994 and June 1995, 20 patients with organic heart diseases combined with atrial fibrillation underwent open heart surgery including Cox-maze 111 procedure. There were 6 men and 14 women with an average age of 48 years (range, 31 to 66 years). Nineteen patients had valvular heart diseases and 1 ventricular septal defEct (VSD). Mean duration of atrial fibrillation was 36 months (:42 months) (range, 1 to 132 months). T e past medical history of thromboembolic events was positive in 7 patients (35%) and left atrial thrombus was detected in 9 patients (45%). The concomitant procedures were mitral valve replacement (MVR) and aortic valve replacement (AVR) in 5 patients, MVR in 4, MVd and tricuspid annuloplasty(TAP) in 4, mitral valvuloplasty(Mln) in 3, Mln and Tln in 1, MIW and coronary artery bypass surgery in 1, AVR in 1, and patch closure of VSD in 1. Mean aortic cross-clamping time was 175 minutes (range, 116 to 270 minutes). Atrial fibrillation recurred in 16 patients (80%) during the early postoperative period, but, recurrent atrial fibrillation was converted to regular rhythm at postoperative forty-first day in average. There was no early or late death in this series of 20 patients and postoperative complications were inappropriate tachycardia in 5 patients (25%), low cardiac output syndrome in 3 (15%), aggravated hemiplegic in 1, and acute renal failure in 1. Mean follow-up interval of patient was 16.5 months (range, 10.5 to 24 months) and all patients are currently in regular rhythm. Seventeen patients (85%) are in sinus rhythm and 3 (15%) in junctional rhythm. Right atrial contraction was detected in 95% of patients and left atrial contraction in 63% on postoperative transthoracic echocardiogram. The surgical treatment of atrial fibrillation concomitant with open heart surgery is warranted in the recent clinical setting of improved myocardial protection technique, considering the untoward side-effects of atrial fibrillation.