Journal Detail Information

1

Cite

Share

Ondansetron Inhibits Voltage-Gated K⁺ Current of Ventricular Myocytes from Pregnant Mouse.

Shanyu CUI ; Hyewon PARK ; Hyelim PARK ; Dasom MUN ; Hyo Eun KIM ; Nuri YUN ; Boyoung JOUNG

International Journal of Arrhythmia.2017;18(2):77-84. doi:10.18501/arrhythmia.2017.012

BACKGROUND: The Htr3a antagonist, ondansetron, has been reported to prolong the QT interval and induce Torsades de pointes in the treatment of postoperative nausea and vomiting. To explore the mechanisms underlying these findings, we examined the effects of ondansetron on the mouse cardiac voltage-gated K⁺ (Kv) channel. METHODS AND RESULTS: Ondansetron increased QT intervals in late pregnant (LP) mice. We measured the Kv channels in freshly isolated left ventricular (LV) myocytes from non-pregnant (NP) and late pregnant (LP) mice, using patch-clamp electrophysiology. Ondansetron blocked Kv current at a dose of 50 µM, and reduced the amplitude of peak current densities in a dose-dependent manner (0, 1, 5, 50 µM), in LP but not in NP mice. In contrast, serotonin and the Htr3 agonist, m-CPBG, increased Kv current densities in NP, but not in LP mice. Interestingly, during pregnancy, serum serotonin levels were markedly increased, suggesting the saturation of the effect of serotonin. Immunostaning data showed that Kv4.3 protein and Htr3a co-localize at the membrane and t-tubule of cardiomyocytes. Moreover, Kv4.3 membrane trafficking was enhanced in response to Htr3a-mediated serotonin stimulation in NP, but not in LP mice. Membrane analysis showed that serotonin enhances Kv4.3 membrane trafficking in NP, but not LP mice. CONCLUSION: Ondansetron reduced Kv current densities, and reduced the Kv4.3 membrane trafficking in LP mouse ventricular cardiomyocytes. This data suggests that QT prolongation by ondansetron is mediated by the reduction of Kv current densities and Kv4.3 membrane trafficking.
Animals ; Electrophysiology ; Membranes ; Mice* ; Muscle Cells* ; Myocytes, Cardiac ; Ondansetron* ; Postoperative Nausea and Vomiting ; Pregnancy ; Serotonin ; Torsades de Pointes

2

Cite

Share

Differential Diagnosis of Supraventricular Tachycardia.

Sung Won JANG

International Journal of Arrhythmia.2017;18(1):43-47. doi:10.18501/arrhythmia.2017.006

Supraventricular tachycardia (SVT) refers to a heterogeneous group of arrhythmias localized within the upper part of the heart (the His bundle or above). In general, the term SVT does not include atrial fibrillation. Common forms of SVT include atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia, focal atrial tachycardia, and atrial flutter. Other, less common arrhythmias also fall under the category of SVT, including inappropriate sinus tachycardia and junctional reentrant/ectopic tachycardia. Paroxysmal supraventricular tachycardia refers to AVNRT and AVRT. SVTs can be identified and classified by clinical manifestation/physical examination, ECG, and/or electrophysiologic analysis.
Arrhythmias, Cardiac ; Atrial Fibrillation ; Atrial Flutter ; Bundle of His ; Diagnosis, Differential* ; Electrocardiography ; Heart ; Tachycardia ; Tachycardia, Atrioventricular Nodal Reentry ; Tachycardia, Sinus ; Tachycardia, Supraventricular*

3

Cite

Share

Supraventricular Tachycardia by Concealed Bypass Tract.

Ki Hong LEE

International Journal of Arrhythmia.2017;18(1):38-42. doi:10.18501/arrhythmia.2017.005

Concealed bypass tract (CBT) results from incomplete development of the atrioventricular (AV) annulus. CBT conducts only in a retrograde direction, and therefore does not cause pre-excitation on standard electrocardiograms. The most common tachycardia associated with CBT is an orthodromic atrioventricular reentrant tachycardia (AVRT): a pathway involving anterograde circuitry through the AV node and His Purkinje system and retrograde conduction over the accessory pathway. Orthodromic AVRT accounts for approximately 90%-95% cases of AVRT. Most incidences of CBT occur at the left free wall. Vagal maneuvers and/or intravenous (IV) adenosine are recommended for first line acute management of AVRT. However, pharmacological therapy with IV diltiazem, verapamil, or beta blockers can also be effective for acute treatment for orthodromic AVRT in patients who do not show pre-excitation on their resting ECG during sinus rhythm. The first-line ongoing therapy for AVRT is catheter ablation of CBT; when catheter ablation is not indicated or preferred, oral beta blockers, diltiazem, verapamil, flecainide, propafenone, or amiodarone are recommended.
Adenosine ; Amiodarone ; Atrioventricular Node ; Catheter Ablation ; Diltiazem ; Electrocardiography ; Flecainide ; Humans ; Incidence ; Propafenone ; Tachycardia ; Tachycardia, Supraventricular* ; Verapamil

4

Cite

Share

Atrioventricular Nodal Reentrant Tachycardia (AVNRT).

Jumsuk KO

International Journal of Arrhythmia.2017;18(1):33-37. doi:10.18501/arrhythmia.2017.004

Atrioventricular nodal reentrant tachycardia is the most common type of supraventricular tachycardia. The initiation and maintenance of tachycardia is caused by the characteristic anatomic and electrophysiologic properties of the atrioverntricular node. Acute management for the termination of tachycardia includes pharmacologic and non-pharmacologic management. There are several options for preventing recurrence of tachycardia, and radiofrequency ablation for modulation of tachycardia circuit can be considered as a primary strategy. A thorough understanding of the unique electrophysiologic features is very essential for optimal management and best possible outcome in cases of invasive management.
Catheter Ablation ; Recurrence ; Tachycardia ; Tachycardia, Atrioventricular Nodal Reentry* ; Tachycardia, Supraventricular

5

Cite

Share

CartoMerge using SoundStar Catheter and Time Force Integral-Based Ablation for Atrial Fibrillation.

Koichi INOUE

International Journal of Arrhythmia.2017;18(1):27-32. doi:10.18501/arrhythmia.2017.003

Catheter ablation for atrial fibrillation is based on pulmonary vein (PV) isolation, but this procedure is thought to be demanding. The visualization of 3-dimensional information that is provided by CartoMerge® (BioSense Webster Inc., Diamond Bar, CA, USA) makes the ablation procedure easier. The SoundStar® catheter (BioSense Webster Inc., Diamond Bar, CA, USA)became available in Korea in September 2016. CartoMerge® using a SoundStar® catheter, which we termed as SoundMerge, is a simple way to obtain good CartoMerge® results. In addition, information on catheter stability and ablation intensity at each site are provided by a new ablation annotation system (CARTO® 3 System, VisiTag™ Module [BioSense Webster Inc., Diamond Bar, CA, USA]), which would be helpful for accomplishing durable PV isolation. In this article, we introduce the methodology of SoundMerge and the setting of the VisiTag™ module that we are performing currently. Effective practical use of these new technologies would improve the quality of ablation procedures.
Atrial Fibrillation* ; Catheter Ablation ; Catheters* ; Diamond ; Korea ; Pulmonary Veins

6

Cite

Share

The Impact of the CHA₂DS₂-VASc Score on Recurrence of Atrial Fibrillation after a Single Catheter Ablation and Atrial Remodeling in Patients with Non-Valvular Atrial Fibrillation.

Chan Hee LEE ; Sang Hee LEE ; Kyu Hwan PARK ; Dong Gu SHIN

International Journal of Arrhythmia.2017;18(1):16-26. doi:10.18501/arrhythmia.2017.002

BACKGROUND AND OBJECTIVES: This study aimed to evaluate the impact of the CHA₂DS₂-VASc score on atrial fibrillation (AF) recurrence after a single catheter ablation procedure in patients with non-valvular AF. We also investigated the correlation between CHA₂DS₂-VASc score and atrial substrate. SUBJECTS AND METHODS: This study evaluated 151 patients who underwent catheter ablation of non-valvular AF. The study population was stratified into group 1 (<2, n=72) and group 2 (≥2, n=79) by CHA₂DS₂-VASc score. The CHA₂DS₂-VASc score was analyzed as a continuous and categorical value for evaluating its impact on AF recurrence after catheter ablation. The left atrial voltage data were analyzed by the categorical values of this score. RESULTS: Post-ablation recurrence (31.6% vs. 18.1%, p=0.046) was observed more frequently in group 2. The mean area of the lowvoltage zone was 75.64±24.81 cm² and 94.44±28.09 cm² in groups 1 and 2, respectively (p=0.005). The left atrial mean voltage in group 2 was 0.99±0.31 mV, significantly lower than that (1.49±0.67 mV, p=0.001) in group 1. The CHA₂DS₂-VASc score was the independent predictor with a modest predictive value for AF recurrence after catheter ablation. CONCLUSION: Our study showed that CHA₂DS₂-VASc score was associated with atrial remodeling and could be useful in stratifying post-ablation recurrence in patients with non-valvular AF.
Atrial Fibrillation* ; Atrial Remodeling* ; Catheter Ablation* ; Catheters* ; Humans ; Recurrence*

7

Cite

Share

Design of Korean Noninvasive Risk Evaluation Study for Sudden Cardiac Death from Infarction or Heart Failure: Myocardial infarction study of K-REDEFINE registry.

Seung Jung PARK ; Gyo Seung HWANG ; Gi Byoung NAM ; Hyung Wook PARK ; Joong Wha CHUNG ; Seung Yong SHIN ; Sang Min KIM ; Jun Hyung KIM ; Young Soo LEE ; Yae Min PARK ; Jong Youn KIM ; Dae Hyeok KIM ; Dae Kyeong KIM ; June NAMGUNG ; Dae Hee SHIN ; Joon Hyouk CHOI ; Hyoung Seob PARK ; Jong Il CHOI ; Jin Seok KIM ; Tae Joon CHA ; Sang Weon PARK ; Jae Sun UHM ; Nam Ho KIM ; Minsoo AHN ; Dong Gu SHIN ; Nuri JANG ; Meemo PARK ; June Soo KIM

International Journal of Arrhythmia.2017;18(1):6-15. doi:10.18501/arrhythmia.2017.001

BACKGROUND AND OBJECTIVES: Despite significant advances in the treatment of acute myocardial infarction (MI), the prevention of sudden cardiac death (SCD), the most common mode of death in patients with MI, remains challenging. Furthermore, previous Korean MI registries did not address the issue of post-MI SCD. Additional risk stratifiers of post-MI SCD are still required to compensate for the limitation of using left ventricular ejection fraction to predict lethal arrhythmic events. SUBJECTS AND METHODS: We designed the first Korean prospective nationwide multicenter registry primarily focused on SCD; the Korean noninvasive Risk Evaluation study for sudden cardiac DEath From INfarction or heart failurE (K-REDEFINE). The registry consists of 2 groups of patients presenting with (1) acute MI or (2) acute heart failure (HF) at 25 tertiary referral cardiovascular centers. The primary endpoint of the MI group study of K-REDEFINE registry is the incidence and risk factors of post-MI SCD. In particular, the association between the risk of SCD and non-invasive Holter-based electrocardiogram (ECG) variables will be evaluated, such as T-wave alternans (marker of repolarization heterogeneity) and heart rate turbulence/variability (a marker of autonomic function). Other secondary study outcomes include atrioventricular arrhythmias, HF-related admission, repeated myocardial ischemic events, stroke, and overall deaths. CONCLUSION AND PERSPECTIVE: The K-REDEFINE registry will provide new prospects for the better management of MI patients with high risk of SCD by clarifying the burden and predictors of SCD and the clinical utility of various non-invasive ambulatory ECG-based variables in risk stratification for SCD in this patient population.
Arrhythmias, Cardiac ; Death, Sudden, Cardiac* ; Electrocardiography ; Heart Failure* ; Heart Rate ; Heart* ; Humans ; Incidence ; Infarction* ; Myocardial Infarction* ; Prospective Studies ; Referral and Consultation ; Registries ; Risk Factors ; Stroke ; Stroke Volume

8

Cite

Share

Changes in Atrioventricular Node Physiology Following Slow Pathway Modification in Patients with AV Nodal Re-entrant Tachycardia: The Hypothetical Suggestion of Mechanism of Noninducibility of AVNRT.

Ju Youn KIM ; Sung Hwan KIM ; Tae Seok KIM ; Ji Hoon KIM ; Sung Won JANG ; Yong Seog OH ; Seung Won JIN ; Tai Ho RHO ; Man Young LEE

International Journal of Arrhythmia.2016;17(1):6-13. doi:10.18501/arrhythmia.2016.001

BACKGROUND AND OBJECTIVES: In cases of radiofrequency catheter ablation (RFCA) for patients with atrioventricular nodal re-entrant tachycardia (AVNRT), complete elimination of slow pathway is not always achievable. Furthermore, in situations of the so-called modified slow pathway, the underlying mechanism of tachycardia elimination remains unclear. SUBJECTS AND METHODS: Patients who underwent RFCA for AVNRT, and showed persistence of dual atrioventricular nodal physiology but no induction of AVNRT after ablation were enrolled. We measured electrophysiologic parameters before and after the ablation procedure. RESULTS: The study subjects included 31 patients (39% men; mean age 43±19 years). The RR interval, Wenckebach cycle length of AV node, slow pathway effective refractory period, maximal AH interval of fast pathway and slow pathway showed no significant changes before and after ablation. However, fast pathway effective refractory period (360±67 vs. 304±55, p<0.001) and differences between slow pathway effective refractory period and fast pathway effective refractory period (90±49 vs. 66±35, p=0.009) were decreased after slow pathway ablation. CONCLUSION: We suggest a possible relationship between the mechanism of tachycardia elimination in AVNRT and an alteration of the re-entrant circuit by removal of the atrial tissue in Koch's triangle. This may be a critical component of providing the excitable gap for the maintenance of tachycardia rather than the electrical damage of slow pathway itself.
Atrioventricular Node* ; Catheter Ablation ; Humans ; Male ; Physiology* ; Tachycardia*

9

Cite

Share

Delayed Sealing of WATCHMAN Device Shunt.

Young Ah PARK ; Jung Sun KIM ; Hui Nam PAK

International Journal of Arrhythmia.2017;18(1):62-65. doi:10.18501/arrhythmia.2017.010

Although left atrial appendage closure is an alternative to warfarin use in atrial fibrillation patients with a high bleeding risk, long-term outcome data in real-world practice are still limited. We describe a delayed shunt on the WATCHMAN fabric membrane and associated stroke at 7 months after the procedure. This shunt on the device surface disappeared at 15 months on the follow-up transesophageal echocardiogram.
Anticoagulants ; Atrial Appendage ; Atrial Fibrillation ; Follow-Up Studies ; Hemorrhage ; Humans ; Membranes ; Stroke ; Warfarin

10

Cite

Share

Where We Can Find Bypass Tract in Ebstein's Anomaly?; a Case of Successful Ablation of Bypass Tract in Ebstein's Anomaly.

June NAMGUNG ; Jae Jin KWAK

International Journal of Arrhythmia.2017;18(1):57-61. doi:10.18501/arrhythmia.2017.009

In patients with Ebstein's anomaly, the localization of accessory pathways may be impeded by abnormal local electrograms recorded along the atrialized right ventricle and by the presence of multiple accessory pathways. We report a case of 50-year-old man diagnosed with Ebstein's anomaly with Wolff-Parkinson-White syndrome who presented with recurrent palpitations. He was referred to our institution for radiofrequency catheter ablation of paroxysmal supraventricular tachycardia. Transthoracic echocardiography revealed the tricuspid valve displaced into the right ventricle, consistent with Ebstein's anomaly. The electrophysiology study showed a right posterolateral accessory pathway. The optimal ablation site was located not in the atrioventricular line of the atrialized ventricular portion, but in the original atrioventricular line.
Accessory Atrioventricular Bundle ; Catheter Ablation ; Ebstein Anomaly* ; Echocardiography ; Electrophysiology ; Heart Ventricles ; Humans ; Middle Aged ; Tachycardia, Supraventricular ; Tricuspid Valve ; Wolff-Parkinson-White Syndrome

DISPLAY OPTIONS

Cite

Share

Cite

Share

Cite

Share

Cite

Share

Cite

Share

Cite

Share

Cite

Share

Cite

Share

Cite

Share

Cite

Share