• Journal of Chest Surgery
• /
• v.46 no.2
• /
• pp.93-97
• /
• 2013

Background: Minimally invasive cardiac surgery has emerged as an alternative to conventional open surgery. This report reviews our experience with atrial septal defect using the da VinciTM surgical robot system. Materials and Methods: This retrospective study included 50 consecutive patients who underwent atrial septal defect repair using the da VinciTM surgical robot system between October 2007 and May 2011. Among these, 13 patients (26%) were approached through a totally endoscopic approach and the others by mini-thoracotomy. Nineteen patients had concomitant procedures including tricuspid annuloplasty (n=10), mitral valvuloplasty (n=9), and maze procedure (n=4). The mean follow-up duration was $16.9{\pm}10.4$ months. Results: No remnant interatrial shunt was detected by intraoperative or postoperative echocardiography. The atrial septal defects were mainly repaired by Gore-Tex patch closure (80%). There was no operative mortality or serious surgical complications. The aortic cross clamping time and cardiopulmonary bypass time were $74.1{\pm}32.2$ and $157.6{\pm}49.7$ minutes, respectively. The postoperative hospital stay was $5.5{\pm}3.3$ days. Conclusion: The atrial septal defect repair with concomitant procedures like mitral valve repair or tricuspid valve repair using the da VinciTM system is a feasible method. In addition, in selected patients, complete port access can be helpful for better cosmetic results and less musculoskeletal injury.

• The Korean Journal of Pharmacology
• /
• v.12 no.2 s.20
• /
• pp.13-19
• /
• 1976

A fluid extract of Zizyphi Semen was employed in this experiment. The cardiac effects of Zizyphi Semen were examined on isolated rabbits atria and heart in situ of anesthetized cats and rabbits. The adrenergic blocking activity and refractory period of cardiac muscle were measured after administration of this drug. In rabbits and cats the antiarrhythmic action of Zizyphi Semen on atrial and ventricular arrhythmias produced by epinephrine or ouabain was examined. The results were following: 1. Zizyphi Semen produced a decrease in rate and contractile amplitude of the isolated rabbit atria and had a week blocking effect on epinephrine acceleration of atrial movement. 2. Zizyphi Semen effectively abolished the spontaneous arrhythmia occurring in the isolated rabbit atria ana the atrial arrhythmia induced by ouabain. 3. Zizyphi Semen produced a marked prolongation of the refractory period in isolated atrial muscle of rabbit. 4. Zizyphi Semen prevented the induction of ventricular arrhythmia arising from excessive dose of epinephrine in anesthetized rabbits and cats. 5. With regard to the ventricular arrhythmia induced by a continuous infusion of ouabain, Zizyphi Semen exerted suppressive effect and produced a marked prolongation of cardiac arrest time in anesthetized rabbits and cats. From the above results, it may be concluded that Zizyphi Semen is effective against atrial and ventricular arrhythmias. The antiarrhythmic effect of this drug may be the result of direct myocardial depressive and partially adrenergic beta receptor blocking activities including prolongation of the refractory period of cardiac muscle.

• The Korean Journal of Physiology
• /
• v.24 no.1
• /
• pp.115-121
• /
• 1990

The interaction between a calcium channel blocker nifedipine and atrial natriuretic peptide (ANP) was examined in normotensive and renal hypertensive rats. The infusion of either ANP or nifedipine produced a significant decrease in mean arterial pressure (MAP). The combined infusion of ANP with nifedipine resulted in a greater fall of MAP than did the infusion of each drug alone. ANP significantly increased urinary volume and excretion of sodium, while nifedipine was without effects. The diuretic/natriuretic effects of ANP were potentiated by the combined infusion with nifedipine. The vasodepressor and renal effects of ANP or nifedipine were qualitatively similar between the normotensive and hypertensive rats. Nifedipine caused an upward and leftward shift of the ANP dose-relaxation curve of the phenylephrine-precontracted thoracic aortic rings isolated from the normotensive rats , suggesting that the vasodilation sensitivity to ANP is increased in the presence of nifedipine. These results indicate that nifedipine enhances the vasodepressor effect of ANP, the likely mechanisms being attributable to a contraction of effective intravascular volume as a consequence of potentiated renal excretion and a greater peripheral vasodilation.

• The Korean Journal of Physiology
• /
• v.22 no.2
• /
• pp.219-230
• /
• 1988

The effect of glycine, structurally the most simple amino acid was investigated on the electrophysiological characteristics of the isolated superfused atrial muscle and sinus node cells of the rabbit heart. Superfusion of the sinus node cell with glycine solution (3, 5 and 8 mM) produced concentration-dependent increments of OS (overshoot potential) and MDP (maximum diastolic potential). Generally action potential amplitude increased as a result of greater increment of OS than that of MDP. The changes in action potential of the sinus node cell peaked in $7{\sim}10{\;}minutes$ after onset of superfusioin. On the contrary to the response to intravenously administered glycine, the rate of spontaneous firing of sinus node cell was invariably increased following superfusion with glycine. Action potential duration manifested as $APD_{60}$ (time to 60% repolarization) was significantly shortened by glycine. And the electrophysiological effects of glycine on the atrial muscle cell were similar to that on the sinus node cells. The results of present study suggest that glycine can exert direct effects on the atrial muscle and sinus node cells of the rabbit heart.

• Journal of Chest Surgery
• /
• v.20 no.2
• /
• pp.241-250
• /
• 1987

We scrutinized the preoperative electrocardiographic and hemodynamic findings in adult atrial septal defects older than 15 years, and then followed up the postoperative electrocardiographic changes sequentially. In preoperative electrocardiographs, the mean PR interval [0.17 sec] was prolonged than normal adults [M;0.13,F;0.15], and the mean QRS axis [93.1*] was deviated to rightward than normal [M;63.7*,F;64.4*], and 122 cases of all 159 patients [77.8%] were in RAD quadrant. The QRS morphology was classified into three groups; a] crista supraventricularis hypertrophy, 25 cases, b] right ventricular outflow tract hypertrophy, 89 cases, c] right ventricular hypertrophy, 44 cases, and normal rs pattern, 1 case. Comparing the QP/QS, Pp/Ps, Rp/Rs in these three groups, Qp/Qs increased a] 2.65 to b] 2.97 and decreased b] 2.97 to c] 2.55, Pp/Ps increased a] 0.27 to b] 0.35 to c] 0.44, and Rp/Rs increased a] 0.1 to b] 0.14 to c] 0.2. In comparing the atrial fibrillation with sinus rhythm, the patient`s mean age was increased [26.4 to 45.7], the mean Qp/Qs was decreased [2.97 to 2.7], the mean Pp/Ps was increased [0.35 to 0.46], the mean Rp/Rs increased [0.14 to 0.2], and the QRS morphology was RVOT hypertrophy;7 cases, RVH;2 cases in all 11 cases. Therefore, the atrial fibrillation was appeared in progressed status. Increasing the mean pulmonary arterial pressure, size of the R` wave in Vl lead increased, and the QRS morphology tended to become severe patterns. Postoperatively, the PR interval shortened and QRS axis tended to normal axis quadrant, and size of R` wave decreased sequentially, atrial fibrillation disappeared in 4 cases. Conclusively, by use of the conventional surface electrocardiography, we could anticipate the hemodynamic changes and the prognosis at outpatient department.

• The Korean Journal of Physiology
• /
• v.26 no.1
• /
• pp.27-35
• /
• 1992

We used the whole cell patch clamp technique to examine the ionic basis for the tail current after depolarizing pulse in single atrial myocytes of the rabbit. We recorded the tail currents during various repolarizations after short depolarizing pulse from a holding potential of -70 mV. The potassium currents were blocked by external 4-aminopyridine and replacement of internal potassium with cesium. The current was reversed to the outward direction above +10 mV. High concentrations of intracellular calcium buffer inhibited the activation of the current. Diltiazem and ryanodine blocked it too. These data suggest that the current is activated by intracellular calcium released from sarcoplasmic reticulumn. When the internal chloride concentration was increased, the inward tail current was increased. The current was partially blocked by the anion transport blocker niflumic acid. The current voltage curve of the niflumic acid sensitive current component shows outward rectification and is well fitted to the current voltage curve of the theoretically predicted chloride current calculated from the constant field equation. The currents recorded in rabbit atrial myocytes, with the method showing isolated outward Na Ca exchange current in ventricular cells of the guinea pig, suggested that chloride conductance could be activated with the activation of Na/ca exchange current. From the above results it is concluded that a chloride sensitive component which is activated by intracellular calcium contributes to tail currents in rabbit atrial cells.

• The Korean Journal of Physiology and Pharmacology
• /
• v.20 no.1
• /
• pp.111-117
• /
• 2016

Vagal nerve activity has been known to play a crucial role in the induction and maintenance of atrial fibrillation (AF). However, it is unclear how the distribution and concentration of local acetylcholine (ACh) promotes AF. In this study, we investigated the effect of the spatial distribution and concentration of ACh on fibrillation patterns in an in silico human atrial model. A human atrial action potential model with an ACh-dependent $K^+$ current ($I_{KAch}$) was used to examine the effect of vagal activation. A simulation of cardiac wave dynamics was performed in a realistic 3D model of the atrium. A model of the ganglionated plexus (GP) and nerve was developed based on the "octopus hypothesis". The pattern of cardiac wave dynamics was examined by applying vagal activation to the GP areas or randomly. AF inducibility in the octopus hypothesis-based GP and nerve model was tested. The effect of the ACh concentration level was also examined. In the single cell simulation, an increase in the ACh concentration shortened $APD_{90}$ and increased the maximal slope of the restitution curve. In the 3D simulation, a random distribution of vagal activation promoted wavebreaks while ACh secretion limited to the GP areas did not induce a noticeable change in wave dynamics. The octopus hypothesis-based model of the GP and nerve exhibited AF inducibility at higher ACh concentrations. In conclusion, a 3D in silico model of the GP and parasympathetic nerve based on the octopus model exhibited higher AF inducibility with higher ACh concentrations.

• The Korean Journal of Physiology and Pharmacology
• /
• v.12 no.5
• /
• pp.267-274
• /
• 2008

Since first discovered in chick skeletal muscles, stretch-activated channels (SACs) have been proposed as a probable mechano-transducer of the mechanical stimulus at the cellular level. Channel properties have been studied in both the single-channel and the whole-cell level. There is growing evidence to indicate that major stretch-induced changes in electrical activity are mediated by activation of these channels. We aimed to investigate the mechanism of stretch-induced automaticity by exploiting a recent mathematical model of rat atrial myocytes which had been established to reproduce cellular activities such as the action potential, $Ca^{2+}$ transients, and contractile force. The incorporation of SACs into the mathematical model, based on experimental results, successfully reproduced the repetitive firing of spontaneous action potentials by stretch. The induced automaticity was composed of two phases. The early phase was driven by increased background conductance of voltage-gated $Na^+$ channel, whereas the later phase was driven by the reverse-mode operation of $Na^+/Ca^{2+}$ exchange current secondary to the accumulation of $Na^+$ and $Ca^{2+}$ through SACs. These results of simulation successfully demonstrate how the SACs can induce automaticity in a single atrial myocyte which may act as a focus to initiate and maintain atrial fibrillation in concert with other arrhythmogenic changes in the heart.

• Journal of Korean Clinical Nursing Research
• /
• v.28 no.1
• /
• pp.23-33
• /
• 2022

Purpose: This study aimed to identify the relationships among disease severity, anxiety, depression, social support, unpleasant symptoms and self-care among patients with atrial fibrillation based on the unpleasant symptom theory, and to examine the mediating effects of unpleasant symptoms. Methods: A cross-sectional study was conducted. The participants were 216 patients with atrial fibrillation who were being followed up on an outpatient basis at a university hospital in Seoul. Data were collected from November 1, 2020 to June 30, 2021, using self-report questionnaires. Data were analyzed using IBM SPSS/WIN 27.0 and PROCESS macro with 95% bias-corrected bootstrap confidence interval(CI). Results: The average age of participants in this study was 66.0years. Disease severity (β=10.19, p<.001) and depression (β=1.53, p<.001) had significant positive relationships with unpleasant symptoms. Also, unpleasant symptoms (β=-0.03, p=.006) had a negative relationship with physical activity, which is a subscale of self- care. Social support (β=0.06, p<.001) was positively related with physical activity. Unpleasant symptoms showed a mediation effect in the relationship between disease severity and physical activity (Bias corrected bootstrap CI -0.65, -0.04). Depression had an indirect effect on physical activity that was mediated by unpleasant symptoms (Bias corrected bootstrap CI -0.11, -0.00). Conclusion: The findings of this study suggest that integrated strategies including physical, psychological, and social factors should be considered to promote self-care in patients with atrial fibrillation.

• Korean Circulation Journal
• /
• v.53 no.8
• /
• pp.550-562
• /
• 2023

Background and Objectives: To identify the factors associated with adverse outcomes following surgery for functional insufficiency of the mitral valve (MV) or tricuspid valve (TV) associated with atrial fibrillation (AF). Methods: We evaluated 100 patients (age, 66.5±10.0 years; 47 males) who consecutively underwent surgery for functional insufficiency of the MV or TV associated with AF between January 2000 and December 2020 at our center. The primary outcome was a composite endpoint of all-cause death, valve reoperation, congestive heart failure (CHF) requiring rehospitalization, and stroke. Results: During follow-up (532 patients-years [PYs]), adverse events included death in 16 (3.0%/yr), MV reoperation in 1 (0.2%/yr), CHF in 14 (2.6%/yr), and stroke in 5 (0.9%/yr) patients, demonstrating a 5-year rate of freedom from the primary endpoint of 69.5%. The rate of postoperative AF was high even in those who underwent AF ablation (n=92), with cumulative rates of 48.1% at 1 year and 60.2% at 5 years. In multivariable analyses, the primary outcome was significantly associated with age (adjusted hazard ratio [aHR], 1.06; 95% confidence interval [CI], 1.02-1.10; p=0.005), chronic kidney disease (aHR, 7.76; 95% CI, 2.28-26.38; p=0.001), left atrial appendage exclusion (aHR, 0.35; 95% CI, 0.16-1.78; p=0.010), and postoperative AF as a time-varying covariate (aHR, 3.33; 95% CI, 1.50-7.40; p=0.003). Conclusion: Among patients undergoing surgery for functional atrioventricular insufficiency associated with AF, a significant proportion showed recurrence of AF over time after concomitant AF ablation, which was significantly associated with poor clinical outcomes.