Publications by authors named "Byung-Chun Jung"

22 Publications

  • Page 1 of 1

Clinical Impact of Implantable Cardioverter-Defibrillator Therapy and Mortality Prediction Model for Effective Primary Prevention in Korean Patients.

J Korean Med Sci 2020 Mar 9;35(9):e49. Epub 2020 Mar 9.

Department of Internal Medicine, Yeungnam University Medical Center, Daegu, Korea.

Background: Studies on the efficacy of implantable cardioverter-defibrillator (ICD) therapy for primary prevention in Asian patients are relatively lacking compared to those for secondary prevention. Also, it is important to stratify which patients will benefit from ICD therapy for primary prevention.

Methods: Of 483 consecutive patients who received new implantation of ICD in 9 centers in Korea, 305 patients with reduced left ventricular systolic function and/or documented ventricular fibrillation/tachycardia were enrolled and divided into primary (n = 167) and secondary prevention groups (n = 138).

Results: During mean follow-up duration of 2.6 ± 1.6 years, appropriate ICD therapy occurred in 78 patients (25.6%), and appropriate ICD shock and anti-tachycardia pacing occurred in 15.1% and 15.1% of patients, respectively. Appropriate ICD shock rate was not different between the two groups (primary 12% vs. secondary 18.8%, = 0.118). However, appropriate ICD therapy rate including shock and anti-tachycardia pacing was significantly higher (primary 18% vs. secondary 34.8%, = 0.001) in the secondary prevention group. Type of prevention and etiology, appropriate and inappropriate ICD shock did not affect all-cause death. High levels of N-terminal pro-B-type natriuretic peptide, New York Heart Association functional class, low levels of estimated glomerular filtration ratio, and body mass index were associated with death before appropriate ICD shock in the primary prevention group. When patients were categorized in 5 risk score groups according to the sum of values defined by each cut-off level, significant differences in death rate before appropriate ICD shock were observed among risk 0 (0%), 1 (3.6%), 2 (3%), 3 (26.5%), and 4 (40%) ( < 0.001).

Conclusion: In this multicenter regional registry, the frequency of appropriate ICD therapy is not low in the primary prevention group. In addition, combination of poor prognostic factors of heart failure is useful in risk stratification of patients who are not benefiting from ICD therapy for primary prevention.
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http://dx.doi.org/10.3346/jkms.2020.35.e49DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7061144PMC
March 2020

Unrestricted use of polymer-free sirolimus eluting stents in routine clinical practice.

Medicine (Baltimore) 2020 Feb;99(8):e19119

Städtische Kliniken Esslingen, Esslingen, Germany.

Stent designs with ultrathin struts may further increase the procedural success of challenging lesion subsets. The objective of this study was to assess the safety and efficacy of ultrathin strut, polymer-free sirolimus eluting stent (PF-SES) implantations in a large scale, unselected patient population.Adult patients underwent percutaneous coronary interventions (PCI) with a thin-strut PF-SES. Data from two all-comers observational studies having the same protocol (ClinicalTrials.gov Identifiers: NCT02629575 and NCT02905214) were pooled. The accumulated target lesion revascularization (TLR) rate at 9-12 months was the primary endpoint. All dual antiplatelet therapy strategies according to the applicable guidelines were permissible.In total, 7243 patients were prospectively enrolled for PCI with PF-SES in stable coronary artery disease or acute coronary syndrome (ACS). Major risk factors in the overall cohort were diabetes (37.3%), ST elevation myocardial infarction (18.1%) and non-ST myocardial infarction (24.6%). The follow-up rate was 88.6% in the overall population. The TLR rate in the overall cohort was 2.2% whereas definite/probable stent thrombosis (ST) occurred in 0.7%. In patients with in-stent restenosis lesions, the major adverse cardiac events rate was 6.4% whereas the corresponding rate for isolated left main coronary artery (LMCA) disease was highest with 6.7% followed by patients with culprit lesions in vein bypasses (VB, 7.1%). The mortality rate in patients treated in VB lesions was highest with 5.4%, followed by the isolated LMCA subgroup (3.4%) and ACS (2.6%).PCI with PF-SES in an unselected patient population, is associated with low clinical event and ST rates. Furthermore, PF-SES angioplasty in niche indications demonstrated favorable safety and efficacy outcomes with high procedural success rates.
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http://dx.doi.org/10.1097/MD.0000000000019119DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7034709PMC
February 2020

Polymer-free sirolimus-eluting stent use in Europe and Asia: Ethnic differences in demographics and clinical outcomes.

PLoS One 2020 13;15(1):e0226606. Epub 2020 Jan 13.

Gachon University Gil Medical Center, Incheon, South Korea.

Background: The objective of this study was to assess regional and ethnic differences in an unselected patient population treated with polymer-free sirolimus-eluting stents (PF-SES) in Asia and Europe.

Methods: Two all-comers observational studies based on the same protocol (ClinicalTrials.gov Identifiers: NCT02629575 and NCT02905214) were combined for data analysis to assure sufficient statistical power. The primary endpoint was the accumulated target lesion revascularization (TLR) rate at 9-12 months.

Results: Of the total population of 7243 patients, 44.0% (3186) were recruited in the Mediterranean region and 32.0% (2317) in central Europe. The most prominent Asian region was South Korea (17.6%, 1274) followed by Malaysia (5.7%, 413). Major cardiovascular risk factors varied significantly across regions. The overall rates for accumulated TLR and MACE were low with 2.2% (140/6374) and 4.4% (279/6374), respectively. In ACS patients, there were no differences in terms of MACE, TLR, MI and accumulated mortality between the investigated regions. Moreover, dual antiplatelet therapy (DAPT) regimens were substantially longer in Asian countries even in patients with stable coronary artery disease as compared to those in Europe.

Conclusions: PF-SES angioplasty is associated with low clinical event rates in all regions. Further reductions in clinical event rates seem to be associated with longer DAPT regimens.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0226606PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6957170PMC
April 2020

Supraventricular tachyarrhythmias in patients with a persistent left superior vena cava.

Europace 2018 07;20(7):1168-1174

Division of Cardiology, Department of Internal Medicine, Keimyung University Dongsan Medical Center, 56, Dalseong-ro, Jung-gu, Daegu, Korea.

Aims: A persistent left superior vena cava (PLSVC) is the most common thoracic venous anomaly. This venous anomaly can impact the evaluation and treatment of supraventricular tachyarrhythmia (SVA). The aim of this study was to assess the proportion and characteristics of PLSVC in adult SVA patients.

Methods And Results: From July 2002 to July 2012, clinical and procedural data from databases of 10 cardiac electrophysiology laboratories in the Yeungnam region of the Republic of Korea were reviewed. Of 6662 adult SVA patients who underwent an EP study or catheter ablation of SVA during the 10-year study period, 18 patients had PLSVC (mean age 47.6 ± 14.8 years, 10 men). The proportion of PLSVC in adult SVA patients was 0.27% (18/6662). SVA type and procedural outcomes of radiofrequency (RF) catheter ablation in these patients were investigated and the results were as follows: successful slow pathway modification in six of seven patients with atrioventricular nodal reentrant tachycardia (AVNRT), successful ablation of accessory pathway in three of four patients with atrioventricular reentrant tachycardia, and successful ablation of atrial tachycardia (cavotricuspid isthmus-dependent in two, septal macroreentry in one, focal from the PLSVC in one) in three of four patients. In one patient with junctional tachycardia, catheter ablation failed. In two patients with atrial fibrillation, catheter ablation was successful.

Conclusion: Among adult SVA patients who underwent an EP study or RF catheter ablation during the 10-year study period, 0.27% had PLSVC. The most common type of SVA was AVNRT. The success rate of catheter ablation was 82% in SVA patients with PLSVC. There were no procedure-related complications.
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http://dx.doi.org/10.1093/europace/eux164DOI Listing
July 2018

Effectiveness of Implantable Cardioverter-Defibrillator Therapy for Heart Failure Patients according to Ischemic or Non-Ischemic Etiology in Korea.

Korean Circ J 2017 Jan 27;47(1):72-81. Epub 2016 Dec 27.

Division of Cardiology, Department of Internal Medicine, Yeungnam University Medical Center, Daegu, Korea.

Background And Objectives: This study was performed to describe clinical characteristics of patients with left ventriculars (LV) dysfunction and implantable cardioverter-defibrillator (ICD), and to evaluate the effect of ICD therapy on survival in Yeongnam province of Korea.

Subjects And Methods: From a community-based device registry (9 centers, Yeongnam province, from November 1999 to September 2012), 146 patients with LV dysfunction and an ICD implanted for primary or secondary prophylaxis, were analyzed. The patients were divided into two groups, based on the etiology (73 with ischemic cardiomyopathy and 73 with non-ischemic cardiomyopathy), and indication for the device implantation (36 for primary prevention and 110 for secondary prevention). The cumulative first shock rate, all cause death, and type and mode of death, were determined according to the etiology and indication.

Results: Over a mean follow-up of 3.5 years, the overall ICD shock rate was about 39.0%. ICD shock therapy was significantly more frequent in the secondary prevention group (46.4% vs. 16.7%, p=0.002). The cumulative probability of a first appropriate shock was higher in the secondary prevention group (p=0.015). There was no significant difference in the all-cause death, cardiac death, and mode of death between the groups according to the etiology and indication.

Conclusion: Studies from this multicenter regional registry data shows that in both ischemic and non-ischemic cardiomyopathy patients, the ICD shock therapy rate was higher in the secondary prevention group than primary prevention group.
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http://dx.doi.org/10.4070/kcj.2016.0242DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5287190PMC
January 2017

Genetic Variation of SCN5A in Korean Patients with Sick Sinus Syndrome.

Korean Circ J 2016 Jan 14;46(1):63-71. Epub 2016 Jan 14.

Department of Internal Medicine, Keimyung University, Daegu, Korea.

Background And Objectives: Due to recent studies that have shown an association between the genetic variation of SCN5A and sick sinus syndrome (SSS), we sought to determine if a similar correlation existed in Korean patients with SSS.

Subjects And Methods: We enrolled 30 patients with SSS who showed a sinus pause (longer than 3.0 s) in Holter monitoring, in addition to 80 controls. All exons including the putative splicing sites of the SCN5A gene were amplified by polymerase chain reaction and sequenced either directly or following subcloning. Wild-type and single nucleotide polymorphisms were expressed in human embryonic kidney cells, and the peak sodium current (INa ) was analyzed using the whole-cell patch-clamp technique.

Results: A total of 9 genetic variations were identified: 7 variations (G87A-A29A, IVS9-3C>A, A1673G-H558R, G3823A-D1275N, T5457C-D1819D, T5963G-L1988R, and C5129T-S1710L) had been previously reported, and 2 variants (A3075T-E1025D and T4847A-F1616Y) were novel; the potential structural effects of F1616Y were analyzed in a three-dimensional model of the SCN5A domain. Patch-clamp studies at room temperature demonstrated that the peak INa was significantly increased by 140% in HEK cells transfected with F1616Y compared with wild-type (-335.13 pA/pF±24.04, n=8 vs. -139.95 pA/pF±23.76, n=7, respectively). Furthermore, the voltage dependency of the activation and steady-state inactivation of F1616Y were leftward-shifted compared with wild-type (Vh activation=-55.36 mv±0.22, n=8 vs. Vh activation=-44.21 mV±0.17, n=7; respectively; Vh inactivation=-104.47 mV±0.21, n=7 vs. Vh inactivation=-84.89 mV±0.09, n=12, respectively).

Conclusion: F1616Y may be associated with SSS.
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http://dx.doi.org/10.4070/kcj.2016.46.1.63DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4720851PMC
January 2016

The Korean Heart Rhythm Society's 2014 Statement on Antithrombotic Therapy for Patients with Nonvalvular Atrial Fibrillation: Korean Heart Rhythm Society.

Korean Circ J 2015 Jan 26;45(1):9-19. Epub 2015 Jan 26.

Division of Cardiology, Department of Medicine, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea.

In patients with nonvalvular atrial fibrillation (AF), the risk of stroke varies considerably according to individual clinical status. The CHA2DS2-VASc score is better than the CHADS2 score for identifying truly lower risk patients with AF. With the advent of novel oral anticoagulants (NOACs), the strategy for antithrombotic therapy has undergone significant changes due to its superior efficacy, safety and convenience compared with warfarin. Furthermore, new aspects of antithrombotic therapy and risk assessment of stroke have been revealed: the efficacy of stroke prevention with aspirin is weak, while the risk of major bleeding is not significantly different from that of oral anticoagulant (OAC) therapy, especially in the elderly. Reflecting these pivotal aspects, previous guidelines have been updated in recent years by overseas societies and associations. The Korean Heart Rhythm Society has summarized the new evidence and updated recommendations for stroke prevention of patients with nonvalvular AF. First of all, antithrombotic therapy must be considered carefully and incorporate the clinical characteristics and circumstances of each individual patient, especially with regards to balancing the benefits of stroke prevention with the risk of bleeding, recommending the CHA2DS2-VASc score rather than the CHADS2 score for assessing the risk of stroke, and employing the HAS-BLED score to validate bleeding risk. In patients with truly low risk (lone AF, CHA2DS2-VASc score of 0), no antithrombotic therapy is recommended, whereas OAC therapy, including warfarin (international normalized ratio 2-3) or NOACs, is recommended for patients with a CHA2DS2-VASc score ≥2 unless contraindicated. In patients with a CHA2DS2-VASc score of 1, OAC therapy should be preferentially considered, but depending on bleeding risk or patient preferences, antiplatelet therapy or no therapy could be permitted.
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http://dx.doi.org/10.4070/kcj.2015.45.1.9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4310986PMC
January 2015

Efficacy and safety of 30-mg fimasartan for the treatment of patients with mild to moderate hypertension: an 8-week, multicenter, randomized, double-blind, phase III clinical study.

Clin Ther 2014 Oct 3;36(10):1412-21. Epub 2014 Aug 3.

Division of Cardiology, Severance Cardiovascular Hospital and Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, South Korea. Electronic address:

Purpose: The standard 60-mg dose of fimasartan, a newly developed selective angiotensin II receptor blocker, is effective and safe for use in patients with mild to moderate hypertension. This study aimed to compare the efficacy and safety of low-dose (30 mg) fimasartan and placebo or valsartan (80 mg) for 8 weeks in patients with mild to moderate hypertension.

Methods: In this randomized trial, 293 patients (219 men; mean age, 54.24 [9.77] years) with mild to moderate hypertension were enrolled. After randomization to receive 30-mg fimasartan (n = 115), placebo (n = 117), or 80-mg valsartan (n = 61), the treatment dose was kept constant without dose escalation for 8 weeks. The primary end point was improvement in sitting diastolic blood pressure (SiDBP) from baseline to 8 weeks that was compared between treatments with low-dose fimasartan and placebo. The secondary end point was the overall efficacy and safety of low-dose fimasartan compared with that of placebo or valsartan.

Findings: At week 8, SiDBP changed by -9.93 (8.86) mm Hg in the fimasartan group and by -2.08 (9.47) mm Hg in the placebo group, which indicated significant antihypertensive efficacy (P < 0.0001). Efficacy was shown at week 4 as measured by SiDBP (-9.96 [7.73] vs -2.27 [7.85] mm Hg; P < 0.0001) or sitting systolic blood pressure (SiSBP) (-16.18 [14.44] vs -1.95 [13.48] mmHg; P < 0.0001) and at week 8 as determined by SiSBP (-15.35 [16.63] vs -2.30 [14.91] mm Hg; P < 0.0001). The fimasartan group exhibited more potent antihypertensive efficacy than the valsartan group both at week 4 (SiDBP, -9.96 [7.73] vs -6.53 [9.58] mm Hg [P = 0.0123]; SiSBP, -16.18 [14.4] vs -7.65 [12.89] mm Hg [P = 0.0002]) and at week 8 (SiDBP, -9.93 [8.86] vs -5.47 [8.96] mm Hg [P = 0.0021]; SiSBP, -15.35 [16.63] vs -7.49 [13.68] mm Hg [P = 0.0021]). Most treatment-emergent adverse events (TEAEs) were mild (89 of 95), and there were no serious TEAEs. The incidence of TEAEs was 19.1% in the fimasartan group, 22.6% in the placebo group, and 13.6% in the valsartan group, with no significant differences.

Implications: Low-dose fimasartan (30 mg) was well tolerated during the study period with no significant TEAEs. Low-dose fimasartan had an effective blood pressure-lowering effect that was greater than that of 80-mg valsartan in patients with mild to moderate hypertension. ClinicalTrials.gov identifier: NCT01672476.
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http://dx.doi.org/10.1016/j.clinthera.2014.07.004DOI Listing
October 2014

Efficacy and safety of antiplatelet-combination therapy after drug-eluting stent implantation.

Korean J Intern Med 2014 Mar 27;29(2):210-6. Epub 2014 Feb 27.

Division of Cardiology, Keimyung University Dongsan Medical Center, Daegu, Korea.

Background/aims: Combination single-pill therapy can improve cost-effectiveness in a typical medical therapy. However, there is a little evidence about the efficacy and tolerability of combination single-pill antiplatelet therapy after percutaneous coronary intervention (PCI) with drug-eluting stents (DES).

Methods: From June to November 2012, in total, 142 patients who met the following criteria were enrolled: at least 18 years old; successful PCI with DES at least 3 months earlier; and regular medication of aspirin and clopidogrel with no side effects. After VerifyNow P2Y12 and aspirin assays, the combination single pill of aspirin and clopidogrel was given and laboratory tests were repeated 6 weeks later.

Results: At baseline, the incidence of aspirin resistance, defined as aspirin reaction unit (ARU) ≥ 550, was 9.2%, that of clopidogrel resistance, defined as P2Y12 reaction unit (PRU) ≥ 230, was 46.5%, and that of percent inhibition of PRU < 20% was 32.4%. At follow-up, the incidence of resistance by ARU value was 7.0%, 50.0% by PRU value, and 35.9% by percentage inhibition of PRU, respectively. The mean values of ARU (431.5 ± 63.6 vs. 439.8 ± 55.2; p = 0.216) and PRU (227.5 ± 71.4 vs. 223.3 ± 76.0; p = 0.350) were not significantly different before versus after antiplatelet-combination single-pill therapy. Five adverse events (3.5%) were observed during the study period.

Conclusions: Combination single-pill antiplatelet therapy, which may reduce daily pill burden for patients after PCI with DES, demonstrated similar efficacy to separate dual-pill antiplatelet therapy.
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http://dx.doi.org/10.3904/kjim.2014.29.2.210DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3956991PMC
March 2014

Genetic Analysis of SCN5A in Korean Patients Associated with Atrioventricular Conduction Block.

Genomics Inform 2012 Jun 30;10(2):110-6. Epub 2012 Jun 30.

Division of Cardiology, Department of Internal Medicine, Keimyung University School of Medicine, Daegu 700-712, Korea.

Recent several studies have shown that the genetic variation of SCN5A is related with atrioventricular conduction block (AVB); no study has yet been published in Koreans. Therefore, to determine the AVB-associated genetic variation in Korean patients, we investigated the genetic variation of SCN5A in Korean patients with AVB and compared with normal control subjects. We enrolled 113 patients with AVB and 80 normal controls with no cardiac symptoms. DNA was isolated from the peripheral blood, and all exons (exon 2-exon 28) except the untranslated region and exon-intron boundaries of the SCN5A gene were amplified by multiplex PCR and directly sequenced using an ABI PRISM 3100 Genetic Analyzer. When a variation was discovered in genomic DNA from AVB patients, we confirmed whether the same variation existed in the control genomic DNA. In the present study, a total of 7 genetic variations were detected in 113 AVB patients. Of the 7 variations, 5 (G87A-A29A, intervening sequence 9-3C>A, A1673G-H558R, G3578A-R1193Q, and T5457C-D1819D) have been reported in previous studies, and 2 (C48G-F16L and G3048A-T1016T) were novel variations that have not been reported. The 2 newly discovered variations were not found in the 80 normal controls. In addition, G298S, G514C, P1008S, G1406R, and D1595N, identified in other ethnic populations, were not detected in this study. We found 2 novel genetic variations in the SCN5A gene in Korean patients with AVB. However, further functional study might be needed.
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http://dx.doi.org/10.5808/GI.2012.10.2.110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3480677PMC
June 2012

Role of the alternans of action potential duration and aconitine-induced arrhythmias in isolated rabbit hearts.

J Korean Med Sci 2011 Dec 29;26(12):1576-81. Epub 2011 Nov 29.

Department of Cardiology, Fatima General Hospital, Daegu, Korea.

Under conditions of Na(+) channel hyperactivation with aconitine, the changes in action potential duration (APD) and the restitution characteristics have not been well defined in the context of aconitine-induced arrhythmogenesis. Optical mapping of voltage using RH237 was performed with eight extracted rabbit hearts that were perfused using the Langendorff system. The characteristics of APD restitution were assessed using the steady-state pacing protocol at baseline and 0.1 µM aconitine concentration. In addition, pseudo-ECG was analyzed at baseline, and with 0.1 and 1.0 µM of aconitine infusion respectively. Triggered activity was not shown in dose of 0.1 µM aconitine but overtly presented in 1.0 µM of aconitine. The slopes of the dynamic APD restitution curves were significantly steeper with 0.1 µM of aconitine than at baseline. With aconitine administration, the cycle length of initiation of APD alternans was significantly longer than at baseline (287.5 ± 9.6 vs 247.5 ± 15.0 msec, P = 0.016). The functional reentry following regional conduction block appears with the progression of APD alternans. Ventricular fibrillation is induced reproducibly at pacing cycle length showing a 2:1 conduction block. Low-dose aconitine produces arrhythmogenesis at an increasing restitution slope with APD alternans as well as regional conduction block that proceeds to functional reentry.
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http://dx.doi.org/10.3346/jkms.2011.26.12.1576DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3230017PMC
December 2011

Isolated double-chambered right ventricle in a young adult.

Korean Circ J 2011 May 31;41(5):272-5. Epub 2011 May 31.

Department of Internal Medicine, Daegu Fatima Hospital, Daegu, Korea.

Double-chambered right ventricle (DCRV) is a rare congenital heart disorder in which the right ventricle is divided by an anomalous muscle bundle into a high pressure inlet portion and a low pressure outlet portion. We report a case of isolated DCRV without symptoms in adulthood, diagnosed through echocardiography, cardiac catheterization and cardiac magnetic resonance imaging.
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http://dx.doi.org/10.4070/kcj.2011.41.5.272DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3116106PMC
May 2011

Effect of valsartan on N-terminal pro-brain natriuretic Peptide in patient with stable chronic heart failure: comparison with enalapril.

Korean Circ J 2011 Feb 28;41(2):61-7. Epub 2011 Feb 28.

Department of Cardiology, Catholic University of Daegu, Daegu, Korea.

Background And Objectives: The plasma concentration of N-terminal pro-brain natriuretic peptide (NT-pro-BNP) is a st-rong prognostic indicator for patients with heart failure (HF) across all stages of the condition. Several clinical trials have de-monstrated convincingly that neurohormonal modulation on the renin angiotensin system (RAS) decreases plasma NT-pro-BNP level and results in favorable outcomes. But there are still limited comparative data on the neuro-hormonal modulatory effects of two RAS inhibitors: angiotensin converting enzyme inhibitor and angiotensin receptor blocker.

Subjects And Methods: This study was a prospective, multi-center, randomized, open-label, controlled, and non-inferiority study involving 445 patients with left ventricular ejection fraction (LVEF) less than 45%. Patients were assigned to receive either valsartan (target dose of 160 mg bid) or enalapril (target dose of 10 mg bid) for 12 months. We compared plasma NT-pro-BNP, high sensitive C-reactive protein (hs-CRP) level and echocardiographic parameters before and after treatment with valsartan or enalapril.

Results: The NT-pro-BNP and hs-CRP levels were significantly decreased after 12 months of treatment with valsartan and enalapril. The percentage change was similar between both groups. LVEF improved and left ventricular internal dimensions were decreased in both groups, and there were no significant differences between two groups.

Conclusion: Valsartan is as effective on improving plasma NT-pro-BNP level as enalapril in patients with stable chronic HF.
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http://dx.doi.org/10.4070/kcj.2011.41.2.61DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3053562PMC
February 2011

Improvement in left ventricular systolic dyssynchrony in hypertensive patients after treatment of hypertension.

Korean Circ J 2011 Jan 31;41(1):16-22. Epub 2011 Jan 31.

Department of Cardiology, Fatima General Hospital, Daegu, Korea.

Background And Objectives: Left ventricular (LV) dyssynchrony has been commonly detected among hypertensive patients with normal LV systolic function and no evidence of congestive heart failure. The purpose of our study was to assess the changes in LV systolic dyssynchrony (SDS(LV)) among hypertensive patients after antihypertensive treatment, and to determine the relationship between SDS(LV) and other conventional echocardiographic parameters.

Subjects And Methods: Forty one hypertensive patients with normal LV ejection fraction were enrolled. By performing a conventional echocardiographic study, the SDS(LV) was measured as the time difference between the shortest and longest time of the peak myocardial systolic velocities among 12 segments of the basal and mid-levels of the 3 apical views, and radial dyssynchrony of the basal (RDS(base)) and mid-levels (RDS(mid)) measured as the time difference between the earliest and latest peak values on the radial strain curves of each level of the parasternal short-axis views.

Results: Compared to baseline after six months of antihypertensive treatment, the SDS(LV) improved significantly (48.7±37.9 ms vs. 29.5±34.1 ms, p=0.020). Also the RDS(base) and RDS(mid) improved significantly in respect to the baseline values (129.9±136.3 ms vs. 38.8±45.4 ms, p=0.002 and 75.2±63.8 ms vs. 28.2±37.7 ms, respectively, p<0.001).

Conclusion: The severity of SDS(LV) improved with antihypertensive treatment, and was associated with the regression of LV mass. Furthermore, it might precede improvement in the mitral inflow pattern, as assessed by conventional echocardiography, so that early detection of the benefit of antihypertensive treatment may be possible.
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http://dx.doi.org/10.4070/kcj.2011.41.1.16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3040398PMC
January 2011

Left atrial volume index as a predictor for occurrence of atrial fibrillation after ablation of typical atrial flutter.

J Cardiol 2010 Nov;56(3):348-53

Division of Cardiology, Catholic University of Daegu, Daegu, Republic of Korea.

Purpose: Radiofrequency catheter ablation of the cavotricuspid isthmus (CTI) is effective in the treatment of typical atrial flutter (AFL) and atrial fibrillation (AF). AF and AFL often coexist. However, AF often occurs following successful ablation of CTI. The aim of this study was to investigate the predictors of concomitant AF following successful ablation of AFL.

Methods: We enrolled 122 patients [59.1 ± 11.3 years, male 100 (82.0%)] with typical AFL, who received successful ablation of the CTI. They were followed up at outpatient clinic (24.6 ± 25.7 months). Twelve-lead electrocardiogram and Holter monitoring were used to confirm the diagnosis of recurrent AFL or AF. We assessed prior history of AF, structural heart disease, left ventricular ejection fraction, left atrial diameter (LAD), left atrial volume index (LAVI), and AFL cycle length.

Results: Among the 122 ablated patients, 15 (12.3%) had recurrent AFL and 33 (27.0%) had recurrent AF. In univariate logistic analysis, LAD and LAVI could significantly predict the recurrence of AF after AFL ablation. However, multivariate logistic regression analysis found that the independent predictor of recurrent AF was LAVI. An LAVI of 42.6 mL may allow for the differentiation between only AFL and AFL with concomitant AF with 69.0% sensitivity and 69.8% specificity.

Conclusions: LAVI might be a useful predictor for occurrence of AF after ablation of typical AFL.
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http://dx.doi.org/10.1016/j.jjcc.2010.07.006DOI Listing
November 2010

Left ventricular dyssynchrony in patients showing diastolic dysfunction without overt symptoms of heart failure.

Korean J Intern Med 2010 Sep 31;25(3):246-52. Epub 2010 Aug 31.

Department of Cardiology, Fatima General Hospital, Daegu, Korea.

Background/aims: Few studies have assessed left ventricular (LV) dyssynchrony in cases of diastolic dysfunction that do not include overt symptoms of heart failure. We hypothesized that systolic or diastolic dyssynchrony involves unique features with respect to the degree of diastolic impairment in isolated diastolic dysfunction.

Methods: We examined 105 subjects with no history of overt symptoms of heart failure and a left ventricular ejection fraction > 50% for mechanical dyssynchrony using tissue Doppler imaging.

Results: In terms of longitudinal dyssynchrony, four cases showed (6.3%) LV intraventricular systolic dyssynchrony (SDS(LV)), whereas none had LV intraventricular diastolic dyssynchrony (DDS(LV)) or co-existing systolic dyssynchrony. Radial dyssynchrony (RD) was found in six cases (9.4%). After adjusting for age, SDS(LV) and DDS(LV) were found to be significantly related to increases in the E/E' ratio (r = 0.405 and p < 0.001 vs. r = 0.216 and p = 0.045, respectively). RD at the base and apex was also significantly related to increases in E/E' (r = 0.298 and p = 0.002 vs. r = 0.196 and p = 0.045, respectively).

Conclusions: Systolic and diastolic dyssynchrony in subjects with isolated diastolic dysfunction but without overt symptoms of heart failure was not as common as in patients with diastolic heart failure; however, the systolic and diastolic intraventricular time delay increased with increases in the E/E' ratio, an indicator of diastolic dysfunction.
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http://dx.doi.org/10.3904/kjim.2010.25.3.246DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2932936PMC
September 2010

Characteristics of myocardial deformation and rotation in subjects with diastolic dysfunction without diastolic heart failure.

Korean Circ J 2009 Dec 30;39(12):532-7. Epub 2009 Dec 30.

Department of Cardiology, Fatima General Hospital, Daegu, Korea.

Background And Objectives: There have been very few pathophysiologic studies on isolated diastolic dysfunction. We hypothesized that the characteristics of isolated diastolic dysfunction would be located, on the clinical continuum, between those of a normal heart and diastolic heart failure.

Subjects And Methods: We enrolled 102 subjects who had no history of overt symptoms of heart failure and who had a left ventricular ejection fraction of more than 50%. They were examined for myocardial deformation and rotation using the two-dimensional speckle tracking image (2D-STI) technique.

Results: The circumferential strains and radial strain at the apical level (RS(apex)) were related to the ratio of the transmitral early peak velocity over the early diastolic mitral annulus velocity (E/E'). After adjustment for age, the RS(apex) showed a positive relationship with the E/E' ratio; whereas, the circumferential strains did not. Instead, the circumferential strains demonstrated a significant correlation with age. Basal rotation and left ventricular (LV) torsion were also related to age, but had no relationship with the E/E' ratio. However, as the E/E' ratio value increased, systolic mitral annular velocity decreased.

Conclusion: Except for the RS(apex), LV myocardial deformation and rotation did not vary with the degree of E/E' ratio elevation when there was no associated diastolic heart failure. Additionally, in clinical situations such as isolated diastolic dysfunction, the advancement of age has a relatively greater influence on characteristics of LV myocardial deformation and rotation rather than on the E/E' ratio.
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http://dx.doi.org/10.4070/kcj.2009.39.12.532DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2801461PMC
December 2009

The relationship between chronic atrial fibrillation and reduced pulmonary function in cases of preserved left ventricular systolic function.

Korean Circ J 2009 Sep 30;39(9):372-7. Epub 2009 Sep 30.

Department of Cardiology, Fatima General Hospital, Daegu, Korea.

Background And Objectives: The purpose of this study was to investigate the relationship between chronic atrial fibrillation (AF) and reduced pulmonary function.

Subjects And Methods: Eighty-six chronic AF patients who were enrolled from annual health examination programs were studied using echocardiography and pulmonary function tests (PFT). Echocardiography and PFT matched for age, gender, and year performed were selected by the control group who had normal sinus rhythms. Patients with ejection fractions <50%, valvular heart disease, or ischemic heart disease were excluded.

Results: In the chronic AF patients, the forced expiratory volume at one second (FEV(1)), FEV1%, and FEV(1)/forced vital capacity (FVC) were significantly reduced, and the right ventricular systolic pressure was significantly increased. Episodes of heart failure were more frequently associated with the chronic AF patients than the controls. In particular, the FEV1% had the most meaningful relationship to chronic AF after an adjustment for cardiovascular risk factors {p=0.003, Exp (B)=0.978, 95% confidence interval (CI):0.963-0.993}.

Conclusion: Reduced FEV1%, which represents the severity of airway obstruction, was associated with chronic AF, and the greater the pulmonary function impairment, the greater the co-existence with AF and congestive heart failure in those with preserved left ventricular systolic function.
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http://dx.doi.org/10.4070/kcj.2009.39.9.372DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2771825PMC
September 2009

Relationship between left atrial size and stroke in patients with sinus rhythm and preserved systolic function.

Korean J Intern Med 2009 Mar;24(1):24-32

Department of Cardiology, Fatima General Hospital, Daegu, Korea.

Background/aims: Increased left atrial (LA) size has been proposed as a predictor of poor cardiovascular outcome in the elderly. In the present study, we evaluated the relationship between LA size and stroke in subjects of all ages who presented with preserved left ventricular systolic function (LVSF) and sinus rhythm (SR), and investigated the relationships between LA size and other echocardiographic parameters of diastolic function.

Methods: A total of 472 subjects were enrolled in the study (161 men, 311 women) and divided into the stroke group (n=75) and control group (n=397). A conventional echocardiographic study was then performed. Subjects with valvular heart disease, atrial fibrillation, or coronary heart disease were excluded.

Results: The mean subject age was 65.2+/-5.1 years in the stroke group and 65.6+/-5.9 years in the control group. Mitral inflow pattern and E & A velocity showed no significant relationship with stroke (p=NS, p=NS, respectively). Left ventricular mass index and LA dimension were significantly related to stroke (p=0.003, p=0.023, respectively), and hypertension showed a marginal relationship with stroke (p=0.050). Age was not related to stroke in the present study (p=NS).

Conclusions: The LA dimension is significantly related to the incidence of stroke. Therefore, strategies for prevention of stroke in patients with preserved LVSF and SR should be considered in cases of LA enlargement.
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http://dx.doi.org/10.3904/kjim.2009.24.1.24DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2687659PMC
March 2009

Ectopic atrial arrhythmias arising from canine thoracic veins during in vivo stellate ganglia stimulation.

Am J Physiol Heart Circ Physiol 2008 Aug 6;295(2):H691-8. Epub 2008 Jun 6.

Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA.

The purpose of the present study was to determine whether thoracic veins may act as ectopic pacemakers and whether nodelike cells and rich sympathetic innervation are present at the ectopic sites. We used a 1,792-electrode mapping system with 1-mm resolution to map ectopic atrial arrhythmias in eight normal dogs during in vivo right and left stellate ganglia (SG) stimulation before and after sinus node crushing. SG stimulation triggered significant elevations of transcardiac norepinephrine levels, sinus tachycardia in all dogs, and atrial tachycardia in two of eight dogs. Sinus node crushing resulted in a slow junctional rhythm (51 +/- 6 beats/min). Subsequent SG stimulation induced 20 episodes of ectopic beats in seven dogs and seven episodes of pulmonary vein tachycardia in three dogs (cycle length 273 +/- 35 ms, duration 16 +/- 4 s). The ectopic beats arose from the pulmonary vein (n = 11), right atrium (n = 5), left atrium (n = 2), and the vein of Marshall (n = 2). There was no difference in arrhythmogenic effects of left vs. right SG stimulation (13/29 vs. 16/29 episodes, P = nonsignificant). There was a greater density of periodic acid Schiff-positive cells (P < 0.05) and sympathetic nerves (P < 0.05) at the ectopic sites compared with other nonectopic atrial sites. We conclude that, in the absence of a sinus node, thoracic veins may function as subsidiary pacemakers under heightened sympathetic tone, becoming the dominant sites of initiation of focal atrial arrhythmias that arise from sites with abundant sympathetic nerves and periodic acid Schiff-positive cells.
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http://dx.doi.org/10.1152/ajpheart.01321.2007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2519231PMC
August 2008

Spontaneous stellate ganglion nerve activity and ventricular arrhythmia in a canine model of sudden death.

Heart Rhythm 2008 Jan 16;5(1):131-9. Epub 2007 Sep 16.

Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA.

Background: Little information is available on the temporal relationship between instantaneous sympathetic nerve activity and ventricular arrhythmia in ambulatory animals.

Objective: The purpose of this study was to determine if increased sympathetic nerve activity precedes the onset of ventricular arrhythmia.

Methods: Simultaneous continuous long-term recording of left stellate ganglion (LSG) nerve activity and electrocardiography was performed in eight dogs with nerve growth factor infusion to the LSG, atrioventricular block, and myocardial infarction (experimental group) and in six normal dogs (control group).

Results: LSG nerve activity included low-amplitude burst discharge activity (LABDA) and high-amplitude spike discharge activity (HASDA). Both LABDA and HASDA accelerated heart rate. In the experimental group, most ventricular tachycardia (86.3%) and sudden cardiac death were preceded within 15 seconds by either LABDA or HASDA. The closer to onset of ventricular tachycardia, the higher the nerve activity. The majority of HASDA was followed immediately by either ventricular arrhythmia (21%) or QRS morphology changes (65%). HASDA occurred in a circadian pattern. HASDA occurred twice as often in the experimental group than in the control group. Electrical stimulation of LSG increased transmural heterogeneity of repolarization (Tpeak-end intervals) and induced either ventricular tachycardia or fibrillation in the experimental group but not in the control group. Immunohistochemical studies revealed increased synaptogenesis and nerve sprouting in the LSG in the experimental group.

Conclusion: Two distinct types of LSG nerve activity (HASDA and LABDA) are present in the LSG of ambulatory dogs. The majority of malignant ventricular arrhythmias are preceded by either HASDA or LABDA, with HASDA particularly arrhythmogenic.
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http://dx.doi.org/10.1016/j.hrthm.2007.09.007DOI Listing
January 2008

Circadian variations of stellate ganglion nerve activity in ambulatory dogs.

Heart Rhythm 2006 Jan;3(1):78-85

Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, CA 90048-1865, USA.

Background: The presence of circadian variations in sympathetic outflow from the stellate ganglia is unclear.

Objectives: The purpose of this study was to continuously record stellate ganglion nerve activity (SGNA) in ambulatory dogs.

Methods: We performed continuous 24-hour left (N = 3) or bilateral (N = 3) SGNA recordings in normal ambulatory dogs using implanted Data Sciences International transmitters. We also performed simultaneous ECG recording (n = 5) or simultaneous ECG and blood pressure recordings (n = 1).

Results: The total duration of continuous ambulatory recording averaged 41.5 +/- 16.6 days. Five dogs had persistent stable recording, and one dog developed hardware malfunction in week 3. SGNA was followed immediately (<1 second) by heart rate and blood pressure elevation and a reduced standard deviation of consecutive activation cycle length (SDNN) from 236 +/- 93 ms to 121 +/- 51 ms (P = 0.007). Heart rate correlated significantly with SGNA. When there was a sudden increase of SGNA, the sudden increase occurred bilaterally in 90% of the episodes. Both heart rate and SGNA showed statistically significant (P <.01) circadian variation. Nadolol (20 mg/day for 5 days) reduced average heart rate from 99 +/- 8 bpm at baseline to 88 +/- 9 bpm (N = 6, P = .001) but did not significantly alter SGNA. Immunohistochemical staining of the stellate ganglia showed tyrosine hydroxylase-positive ganglion cells and nerves at the recording site.

Conclusion: There is a circadian variation in sympathetic outflow from canine stellate ganglia. Circadian variation of SGNA is an important cause of circadian variations of cardiac sympathetic tone.
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http://dx.doi.org/10.1016/j.hrthm.2005.09.016DOI Listing
January 2006