• Journal of Yeungnam Medical Science
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• v.18 no.2
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• pp.267-276
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• 2001

Background: P wave dispersion(PWD) is defined as the difference between the maximum and minimal P wave duration in any of the 12 leads of the surface ECG. The prolongation of atrial conduction time and the inhomogeneous propagation of sinus impulse are known electrophysiologic features in patients with paroxysmal atrial fibrillation(PAF). The purpose of this study was to determine the role of P wave dispersion for the prediction of PAF and to evaluate the effectiveness of prophylactic antiarrhythmic therapy. Materials and Methods: The study population included 20 patients with a history of idiopathic PAF and 20 age and sex matched healthy control subjects. We measured the maximum P wave duration(P maximum) and P wave dispersion from 12 lead ECG. Results: P maximum and P dispersion in idiopathic PAF were significantly higher than normal control group($97.2{\pm}12$, $48.5{\pm}9$ msec vs, $76.5{\pm}11$, $21{\pm}8$ msec, respectively p<0.001, <0.001). After 12-month follow up period P maximum and P dispersion were significantly reduced than those of initial state($77.2{\pm}13$, $26.4{\pm}9$ msec vs. $97.2{\pm}12$, $48.5{\pm}9$ msec, respectively p<0.001,<0.001). Conclusion: P dispersion and P maximum were significantly different between patients with idiopathic PAF and healthy control group. Those are easily accessible, non-invasive simple electrocadiographic markers that could be used for the prediction and prognostic factors of idiopathic PAF.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.5
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• pp.313-323
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• 2022

Atrial fibrillation (AF) is the most common supraventricular arrhythmia, and it corresponds highly with exercise intensity. Here, we induced AF in mice using acetylcholine (ACh)-CaCl₂ for 7 days and aimed to determine the appropriate exercise intensity (no, low, moderate, high) to protect against AF by running the mice at different intensities for 4 weeks before the AF induction by ACh-CaCl₂. We examined the AF-induced atrial remodeling using electrocardiogram, patch-clamp, and immunohistochemistry. After the AF induction, heart rate, % increase of heart rate, and heart weight/body weight ratio were significantly higher in all the four AF groups than in the normal control; highest in the high-ex AF and lowest in the low-ex (lower than the no-ex AF), which indicates that low-ex treated the AF. Consistent with these changes, G protein-gated inwardly rectifying K⁺ currents, which were induced by ACh, increased in an exercise intensity-dependent manner and were lower in the low-ex AF than the no-ex AF. The peak level of Ca²⁺ current (at 0 mV) increased also in an exercise intensity-dependent manner and the inactivation time constants were shorter in all AF groups except for the low-ex AF group, in which the time constant was similar to that of the control. Finally, action potential duration was shorter in all the four AF groups than in the normal control; shortest in the high-ex AF and longest in the low-ex AF. Taken together, we conclude that low-intensity exercise protects the heart from AF, whereas high-intensity exercise might exacerbate AF.

• The Korean journal of internal medicine
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• v.39 no.3
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• pp.458-468
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• 2024

Background/Aims: The SAMe-TT₂R₂ score is used for assessing anticoagulation control (AC) quality with warfarin. However, it is hard to apply SAMe-TT₂R₂ score in Asian patients with atrial fibrillation (AF), because it has not been proven in those populations. This study aimed to validate the SAMe-TT₂R₂ score in Asian patients with AF and suggest a modified SAMe-TT₂R₂ score for this population. Methods: We analyzed 710 Korean patients with AF who were using warfarin. The AC quality was assessed as the mean time in therapeutic range (TTR). Each component of SAMe-TT₂R₂ score was evaluated for the relationship with AC. Further clinical factors that predict AC were analyzed. Identified factors were re-assorted and constructed as SA₂Me-TTR scoring system. Results: Of the components of the SAMe-TT₂R₂ score, female, age, and rhythm control were associated with AC. Heart failure and renal insufficiency were newly identified factors associated with AC. The modified SA₂Me-TTR score was reconstructed with the relevant risk factors (S, female gender, 1 point; A, age < 60 yr, 2 points; Me, medical history of heart failure, 1 point; T, treatment for rhythm control, 1 point; T, history of stroke or transient ischemic attack, 1 point; R, renal insufficiency, 1 point). The modified SA₂Me-TTR score demonstrated an excellent relationship with the grading of AC. The modified SA₂Me-TTR score ≤ 1 identified patients with good AC (hazard ratio 2.46, 95% CI 1.75-3.47). Conclusions: The modified SA₂Me-TTR score was useful for guiding oral anticoagulants selection in Asian patients with AF.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.4
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• pp.319-324
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• 2000

The causal relationship between heat shock protein (HSP) and second window of cardioprotective effect is still undetermined. In the present study, we assessed whether HSP-producing substances, amphetamine and ketamine, afforded protection against reperfusion-induced ventricular fibrillation (VF) and these protective effect remained after the inhibition of HSP72 production by quercetin, a mitochondrial ATPase inhibitor. Adult mongreal male cats $(n=60,\;2.5{\sim}4\;kg)$ were used in this study. Experimental animals were divided into five groups; control group (n=15), amphetamine ('A', n=11) group, ketamine ('K', n=9) group, amphetamine-ketamine ('AK', n=16) group and amphetamine-ketamine-quercetin ('AKQ', n=9) group. Twenty-four hours after the drug treatment, an episode of 20-min coronary artery occlusion was followed by 10-min reperfusion. The incidence of reperfusion-induced VF in the AK and AKQ groups was significantly lower than that in control group (p＜0.01). After the ischemia/reperfusion procedure, western blot analysis of HSP72 expression in the myocardial tissues resected from each group was performed. HSP72 production in the AK group was marked, whereas HSP72 was not detected in the AKQ and control groups. These results suggest that the suppressive effect against reperfusion-induced VF induced by amphetamine and ketamine is not mediated by myocardial HSP72 production but by other mechanisms.

• Journal of Chest Surgery
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• v.47 no.4
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• pp.358-366
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• 2014

Background: To improve sinus rhythm conversion, the Cox maze III procedure with narrow mazes (width: ${\leq}3.0cm$) was performed in combination with left atrial volume reduction. Methods: From October 2007 to April 2013, 87 patients with atrial fibrillation (paroxysmal in 3, persistent in 14, and permanent in 70) underwent the Cox maze procedure concomitant with another cardiac procedure. They were followed-up with serial electrocardiographic and echocardiographic studies. We used 24-hour Holter monitoring tests to evaluate postoperatively symptomatic patients. Results: At the mean follow-up time of 36.4 months, 81 patients (94.2%) had sinus rhythm and two were on anti-arrhythmic medication (one on a beta-blocker and the other on amiodarone). Five patients (5.8%) with postoperative recurrent and persistent atrial fibrillation never experienced sinus rhythm conversion; however, they did not require any medication for rate control. On postoperative echocardiography, the left atrial A waves were more frequently observed after concomitant mitral valve repair than after concomitant mitral valve replacement (82.4% vs. 40.4%, respectively; p<0.001). Conclusion: For the Cox maze procedure, narrow mazes and atrial volume reduction resulted in excellent sinus rhythm conversion without the preventive use of anti-arrhythmic drugs, and they did not affect the presence of the left atrial A waves on echocardiography.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.425-430
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• 2014

Amyloidogenic proteins often exhibit fibrillar polymorphism through alternative assembly processes, which has been considered to have possible pathological implications. Here, firefly luciferase (LUC) is shown to induce amyloid polymorphism of ${\alpha}$-synuclein, the major constituent of Lewy bodies found in Parkinson's disease, by acting as a novel template. The drastically accelerated fibrillation kinetics of ${\alpha}$-synuclein with LUC required the nucleation center produced by the active enzyme of LUC. Fluorescent dye binding, transmission electron microscopy, and Fourier transformed infrared spectroscopy revealed the morphologically distinctive amyloid fibrils of ${\alpha}$-synuclein prepared in the absence or presence of LUC. As the altered morphological characteristics became inherent to the mature fibrils, those properties were inherited to next-generations via nucleation-dependent fibrillation process. The seed control, therefore, would be an effective means to modify amyloid fibrils with different biochemical characteristics. In addition, the LUC-directed amyloid fibrillar polymorphism also suggests that other cellular biomolecules including enzymes in general are able to diversify amyloid fibrils, which could be self-propagated with diversified biological activities, if any, inside cells.

• Biomolecules & Therapeutics
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• v.7 no.4
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• pp.347-353
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• 1999

Osteoarthrosis was induced in rabbit knees through resecton of anterior cruciate ligament. Sodium hyaluronate (1%) was administerated into articular space at the dose levels of 0.1 mg/kg once a week using 1ml sylinge and 26G needle for test groups. Saline was administrated for control groups. After 6 and 12 weeks, animals were sacrificed to conduct macroscopic observation and histopathologic examination. The articular lesions were evaluated and test groups were compared with control groups. No significant differencies were showed between test groups and control groups at macroscopic observation in both 6- and 12- week groups. In histopathologic examination, control groups showed higher osteoarthrosis than test groups. The articular surfaces of control groups showed fibrillation, denudation, pannus formation and hypocellularity. The articular surfaces of test groups showed fibrillaton and hypercellularity. These indicate that sodium hyaluronate has inhibitory effects on osteoarthrosis at least in rabbit and could be used for treatment of osteoarthrosis.

• Journal of Biomedical Engineering Research
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• v.23 no.1
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• pp.1-8
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• 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
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• v.56 no.2
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• pp.90-98
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• 2023

Background: Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. Totally thoracoscopic ablation (TTA) is a surgical treatment showing a high success rate as a hybrid procedure with radiofrequency catheter ablation to control AF. This study compared the early complications of warfarin and non-vitamin K antagonist oral anticoagulants (NOACs) in patients who underwent TTA. Methods: This single-center retrospective cohort study enrolled patients who underwent planned TTA for AF from February 2012 to October 2020. All patients received postoperative anticoagulation, either with warfarin or a NOAC (apixaban, rivaroxaban, dabigatran, or edoxaban). Propensity score matching was performed for both groups. Early complications were assessed at 12 weeks after TTA and were divided into efficacy and safety outcomes. Both efficacy and safety outcomes were compared in the propensity score-matched groups. Results: Early complications involving efficacy outcomes, such as stroke and transient ischemic attack, were seen in 5 patients in the warfarin group and none in the NOAC group. Although the 2 groups differed in the incidence of efficacy outcomes, it was not statistically significant. In safety outcomes, 11 patients in the warfarin group and 24 patients in the NOAC group had complications, but likewise, the between-group difference was not statistically significant. Conclusion: Among patients who underwent TTA, those who received NOACs had a lower incidence of thromboembolic complications than those who received warfarin; however, both groups showed a similar bleeding complication rate. Using a NOAC after TTA does not reduce efficacy and safety when compared to warfarin.

• 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.