bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of Ventricular Premature Contraction Showing Interpolated Bigeminy —Strong Modulation Hypothesis—
Authors: Takayanagi Kan , Sakai Yoshihiko 
Published: August 2012

Recent advances in invasive electrocardiology dramatically revealed the unique nature of atrial fibrillation originating from the pulmonary veins. By the same invasive technique, the origin of ventricular premature contraction (VPC) has been clarified as being located in the pulmonary outflow tract, ventricular Purkinje fibers or coronary cusps. Despite these clarifications, the essential mechanism of VPCs still remains uncertain. In addition to automaticity, the possible contribution of reentrant pathway cannot be fully ruled out. To analyze the mechanism, we previously reported on a two dimensional color display of interectopic intervals in VPC patients. This display could estimate the fundamental mechanism of VPC for a full day and clearly differentiate parasystole from fixed coupling interval VPCs.In this review, first we briefly document the historical background. In order to explain the mechanism of the much more frequently observed fixed coupling interval VPCs, we introduced a new version of color display. Using this modified version, a unique electrocardiogram associated with heart rate doubling during interpolated VPC bigeminy was depicted. The role of interpolated VPCs applied to phase analysis was stressed. From the findings, we developed a strong modulation hypothesis.Clinical significance of interpolated VPC together with heart rate doubling and harmonic feature was illustrated. Our hypothesis can be applied not only to specific form of parasystole with various coupling intervals but also to fixed coupling interval VPCs. The modified display can roughly discriminate the relative ratio of parasystole cycle length from sinus cycle length. Furthermore, simple estimation of the intrinsic automaticity cycle length together with the heart rate dependence in individual patients was possible.
A New Proposal for Crossing Two or More Sheaths through Single Trans‐Septal Puncture in Ablation of Atrial Fibrillation: Experience with Steerable Introducer
Authors: Okamoto Mitsunori , Sueda Takashi , Hashimoto Masaki , Fukuda Yukihiro , Shintani Yumiko , Matsumoto Takeshi , Iwasaki Toshitaka , Kinoshita Hiroki 
Published: August 2012

Introduction: We have sometimes experienced difficulty in crossing two or more sheath through one septal puncture for catheter based pulmonary vein isolation.Methods: Subjects were 32 consecutive patients (25 men and 7 women) ranging from age 43 to 76 with paroxysmal or sustained atrial fibrillation, who underwent extensive pulmonary vein isolation. After the Brockenbrough puncture using a Daig SL0 dilator sheath system, the sheath dilator was pulled back into the right atrium leaving the 0.035 inch guide wire in the left atrium. In the initial 19 patients, we attempted to put the second Daig SL0 sheath in the left atrium using the electrode catheter. In the 13 subsequent patients, we used the SL0 sheath dilator in 6 and a newly developed steerable introducer in 7 patients. The sheath dilator was aligned with the anchored first guide wire under the guidance of biplane fluoroscopy. After advancing the second dilator system in the left atrium, the system was pulled back leaving the second guide wire in the left atrium. The third sheath system was positioned in the same manner.Results: In the two of the 19 conventional cases, the second sheath with electrode did not pass the septum and needed another Brokenbrough puncture. In the 13 subsequent cases using the new method, the sheath dilator systems were successfully positioned in all cases with no major complications. The steerable sheath was very useful for aiming at the puncture site.In conclusion, the new technique was very useful and simple for crossing two or more sheaths through a single trans‐septal puncture.
In vitro Assessment of Electromagnetic Interference due to Low‐Band RFID reader/writers on Active Implantable Medical Devices
Authors: Futatsumori Shunichi , Kawamura Yoshifumi , Hikage Takashi , Nojima Toshio , Koike Ben , Fujimoto Hiroshi , Toyoshima Takeshi 
Published: August 2012

Introduction: The electromagnetic interference (EMI) of active implantable medical devices (AIMDs) due to 125–135 kHz and HF (13.56MHz) radio‐frequency identification (RFID) reader/writers are discussed based on in vitro experiments. The purpose of this paper is to clarify the detailed EMI occurrence conditions of both implantable cardiac pacemakers and implantable cardioverter defibrillators (ICDs) when used in proximity to commercial lowband RFID reader/writers.Methods and results: A total of 20 types of pacemakers and 7 types of ICDs from 9 manufacturers are used in the experiments. The tested RFID reader/writers are 4 types of 125–135 kHz antennas and 26 types of HF antennas. The test system is newly constructed based on the one previously proposed for the estimation of EMI due to mobile phones. The measured reactions are missing of pacing pulses and generation of asynchronous pulses for pacemaker functions and inappropriate tachyarrhythmia detection and delivery of therapy for ICDs. In addition, measured EMI characteristics strongly depend on intermittent period of RFID signals. However, all AIMDs tested return to normal operation once removed from RFID exposure.Conclusion: The detailed EMI characteristics of AIMDs and low‐band RFID reader/ writers are obtained to prevent adverse interactions.
A New Device for Protection from Radiation Exposure during Catheter Ablation
Authors: Kowase Shinya , Kurosaki Kenji , Miyamoto Mihoko , Oginosawa Yasushi , Sugiyasu Aiko , Kubota Shoichi , Nogami Akihiko 
Published: August 2012

Background: As the indications for catheter ablation of complex arrhythmias has expanded, the radiation exposure to the operator has increased. Recently, a radiation protection cabin (RPC) has been developed. However, the effect of reducing the radiation exposure of the operator has not been fully evaluated. The aim of this study was to evaluate the efficacy the RPC during catheter ablation (CA).Method & Results: Twenty‐six patients who underwent CA were included in this study. The patients were divided into two groups, those in which the RPC was used (RPC group; n = 11) and those in which it was not used (no RPC group; n = 15). The radiation dosage was measured with thermoluminescent dosimeters placed on the head and chest. The decrement rates at the unprotected area of not only the operator but also the assistant in the RPC group were significantly higher than those in the no RPC group. There was no significant difference in the decrement rate in the protected areas between the two groups.Conclusion: This study shows that the RPC protects from radiation exposure not only the operator but also the assistant and frees us from using a heavy apron.
Radiofrequency Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia in Patient with Interruption of Inferior Vena Cava
Authors: Suzuki Kou , Kaneko Shingo , Otomo Kenichiro , Hirono Yoshiyuki , Terai Tomoko , Imoto Hiroki , Takayama Emi , Iwama Toru , Kubo Ichiro 
Published: August 2012

We present a 72‐year‐old man with interruption of inferior vena cava (IVC) with azygos continuation, who underwent radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT).We recorded a His bundle electrogram with an electrode catheter positioned in the aortic root. We also introduced an electrode catheter through the right femoral vein, advanced it via an enlarged azygos vein and the superior vena cava and positioned it at the right ventricular apex (RVA). AVNRT was induced by programmed pacing from a coronary sinus catheter introduced through the left subclavian vein. It was successfully ablated with an ablation catheter introduced through the right internal jugular vein.In a patient with interruption of IVC, it is impossible to access the right side of the heart directly via femoral vein and IVC. In this case, however, alternative routes to the His bundle, RVA and ablation site enabled us to perform an electrophysiologic study and a successful catheter ablation.
Does Atrial‐Pacing from Different Intra‐Atrial Sites for Atrial Fibrillation Effect Pulmonary Venous Pressure?
Authors: Mitsutake Chiharu , Muraoka Soichi , Takashima Hideo , Nakashima Hideko , Yasuda Tomoo , Matsumoto Naomichi , Kumagai Koichiro , Saku Keijiro 
Published: August 2012

Introduction: Coronary sinus (CS) and biatrial pacing have been reported to be more effective than right atrial appendage (RAA) pacing for preventing atrial fibrillation (AF). However, the effects of atrial pacing on hemodynamics are still unknown.Methods and Results: Eleven patients with AF who underwent PV isolation were studied. Two quadripolar electrode catheters were placed in RAA and CS.After a transseptal approach, a thermodilution catheter was introduced into the left superior pulmonary vein (LSPV). The mean LSPV pressure was directly measured during pacing from the distal site of the CS (CS‐d) and RAA, and simultaneous pacing from CS‐d and RAA. The P wave duration during pacing from the RAA+CS‐d was significantly shorter than that during pacing from the RAA (83 ± 16 vs. 121 ± 18 ms, P < 0.05). No significant difference in LSPV pressure was found among the three pacing configurations (RAA, CS‐d, RAA+CS‐d pacing; 16 ± 7, 16 ± 4, 17 ± 3 mmHg, respectively).Conclusions: LSPV pressure was not affected by CS‐d, or biatrial pacing. Shortening of the P wave duration by biatrial pacing may contribute to the prevention of AF. The electrophysiological effects of pacing may play a more important role in preventing AF rather than the hemodynamic effects.
Electrocardiographic Characteristics of Fasciculoventricular Pathways: Analysis of Five Cases
Authors: Saito Akihiro , Kaneko Yoshiaki , Nakajima Tadashi , Irie Tadanobu , Ota Masaki , Kato Toshimitsu , Iijima Takafumi , Ito Toshio , Manita Mamoru , Kurabayashi Masahiko 
Published: August 2012

Introduction: Fasciculoventricular (FV) accessory pathways are rare variants of preexcitation syndrome and published data on the ECG of FV pathways are limited. The purpose of this study was to analyze the electrocardiographic characteristics of FV pathways.Methods: We enrolled 5 patients (mean age, 26.8 ± 15.1 years; range 15–49 years, 2 male) with FV pathways which were diagnosed based on the standard electrophysiologic criteria. According to the standard criteria for the ECG classification of manifest Wolff‐Parkinson‐White (WPW) syndrome, the ECGs were classified as type A, B or C. The polarity of delta wave in each lead of each patient was divided into positive, flat or negative and was applied to the stepwise ECG algorithms of atrioventricular accessory pathway previously published by Fitzpatrick, Arruda and Iturralde.Results: Type A was found in one patient (Case No 4), type B in one patient (Case No 5) and type C in three patients (Case No 1, 2 and 3). Based on stepwise ECG algorithm, all cases corresponded to the polarity of the delta wave in patients with right anteroseptal, posteroseptal, right anterolateral or left anterolateral AP. In all three cases exhibiting type C, the polarity of delta wave in lead V2 was flat.Conclusions: ECGs of FV pathways may be misidentified as ECG of WPW syndrome, and may present with any preexcitation pattern of type A, B or C.
Electrophysiological Remodeling in Heart Failure Dyssynchrony vs. Resynchronization
Authors: Aiba Takeshi , Tomaselli Gordon F. , Shimizu Wataru 
Published: August 2012

The electrophysiological hallmark of cells and tissues isolated from failing hearts is prolongation of action potential duration (APD) and conduction slowing. In human studies and a number of animal models of heart failure, functional downregulation of K currents and alterations in depolarizing Na and Ca currents and transporters are demonstrated. Alterations in intercellular ion channels and matrix contribute to heterogeneity of APD and conduction slowing. The changes in cellular and tissue function are regionally heterogenous particularly in the heart failure with dyssynchronous LV contraction (DHF). Furthermore, β‐adrenergic signaling and modulation of ionic currents is blunted in heart failure.Cardiac resynchronization therapy (CRT) partially reversed the DHF‐induced downregulation of K current and improved Na channel gating. CRT significantly improved Ca homeostasis especially in myocytes from late‐activated, lateral wall, and restores the DHF‐induced blunted β‐adrenergic receptor responsiveness. CRT abbreviated DHF‐induced prolongation of APD in the lateral wall myocytes and reduced the LV regional gradient of APD, and suppressed development of early afterdepolarizations.In conclusion, CRT partially restores DHF‐induced ion channel remodeling, abnormal Ca homeostasis, blunted β‐adrenergic response and regional heterogeneity of APD, thus may suppress ventricular arrhythmias and contribute to the mortality benefit of CRT as well as improve mechanical performance of the heart.
Efficacy of Additional Amiodarone Therapy in Patients with an Implantable Cardioverter‐Defibrillator
Authors: Matsumoto Naomichi , Kumagai Koichiro , Ogawa Masahiro , Matsuo Kunihiro , Yasuda Tomoo , Takashima Hideo , Mitsutake Chiharu , Muraoka Soichi , Matsunaga Akira , Miura Shin‐ichiro , Saku Keijiro 
Published: August 2012

Introduction: We examined whether the additional use of amiodarone (AMD) under implantable cardioverter‐defibrillator (ICD) therapy may have beneficial effects in patients at risk for lethal ventricular arrhythmias with structural heart diseases.Methods: Sixty patients (47 males, mean age, 62 ± 13 years) with structural heart disease who underwent ICD implantation were retrospectively analyzed. There were 2 groups: one group (AMD group) was treated with AMD (n = 33) and the other group (non‐AMD group) was treated without AMD (n = 27). We compared the incidence and appropriateness of ICD shock therapy between two groups.Results: During a mean follow‐up of 28 ± 17 months, we identified a total of 62 episodes in 18 patients (30%) who received ICD shock therapy. ICD shock episodes were significantly less frequent in AMD group than in non‐AMD group (15% versus 48%, P < 0.01), while inappropriate shock episodes were greater in non‐AMD group than in AMD group (49% versus 4%, P = 0.03). In cumulative probability of shock events, the risk of events was significantly lower in AMD group (P = 0.007). Of 4 patients who died in AMD group, we observed one fatal pulmonary fibrosis.Conclusions: Additional AMD therapy in patients with an ICD may be effective in reducing the risk of shock discharge.
Nonapeptide Hormones Oxytocin and Vasopressin Distinctly Regulate Cav1.2 L‐type Calcium Channel Expression in Cardiomyocytes
Authors: Morishima Masaki , Tahara Shintaro , Wang Yan , Kaku Toshihiko , Ono Katsushige 
Published: August 2012

Background: The neurohypophyseal hormones oxytocin (OT) and [Arg8]‐vasopressin (AVP) have recently been implicated in cardiac function. This study was designed to investigate actions of OT and AVP on regulation of the voltage‐gated Ca2+ channel in cardiomyocytes.Methods and Results: Cultured neonatal rat cardiomyocytes were stimulated with OT or AVP (10‐8 M to 10‐6 M) for 24‐72 h, followed by real‐time PCR and patch clamp studies. Although OT did not exert any modulatory effect on L‐type Ca2+ channel current, as a shortterm effect, stimulation of cardiomyocytes with OT but not AVP decreased the expression of Cav1.2 mRNA with a reduced L‐type Ca2+ channel current. A transcription factor CREB mRNA expression was down‐regulated by OT treatment, although T‐type Ca2+ channels (Cav3.1, Cav3.2) were unaffected by OT or AVP.Conclusion: OT but not AVP down‐regulates L‐type Ca2+ channel expression through the inhibition of CREB transcriptional, suggesting a novel mechanism of OT action in the cardiac electrophysiology.
Optimal Right Ventricular Pacing Site from the Perspective of QRS Duration, Heart Function and the Configuration of 12‐lead Electrocardiogram
Authors: Noro Mahito , Kujime Shingo , Ito Naoshi , Enomoto Yoshinari , Moriyama Akiyoshi , Nakae Takeshi , Numata Ayaka , Sakai Tuyoshi , Tezuka Naoki , Sakata Takao , Sugi Kaoru 
Published: August 2012

Introduction: It has become clear that the onset of heart failure is closely linked to right apex pacing, which lengthens the QRS duration and evokes discoordinate contraction of the left ventricle (LV). Currently, it is thought that the site inducing the shortest QRS duration is optimal for pacing.Objectives: The purpose of this study was to ascertain the pacing site inducing the shortest QRS duration and to examine the configuration of the 12‐lead electrocardiogram and heart function while pacing at this site.Methods: Nine patients with normal heart function were enrolled. Pacing at right ventricular outflow, mid‐interventricular septum (MS), and right ventricular apex was performed. QRS duration was measured and the configuration of the 12‐lead electrocardiogram changed by pacing was studied. Output and LV dp/dt were calculated at each pacing site.Results: QRS duration became shorter with MS pacing and the pacing lead situated at the periphery of the coronary sinus and turned in a posterior direction. The configuration of the 12‐lead electrocardiogram showed an Rs or rS pattern with II, III, and aVF leads. Output and LV dp/dt showed a tendency to increase with MS pacing.Conclusion: It is thought that mid‐interventricular septum pacing shortens the QRS duration.
Prevalence and QT Interval of Early Repolarization in a Hospital‐based Population
Authors: Hayashi Hideki , Miyamoto Akashi , Ishida Katsuya , Yoshino Tomohide , Sugimoto Yoshihisa , Ito Makoto , Horie Minoru 
Published: August 2012

Background: Early repolarization, which was regarded as benign, has recently been associated with malignant arrhythmia. Despite the newly emerged importance of early repolarization, little is known about prevalence and QT interval of early repolarization. Methods: Early repolarization (defined as an elevation at the junction between QRS complex and ST segment ≥ 0.1 mV in at least 2 leads) was assessed in database containing 308,391 ECGs consisting of 102,065 patients (52,779 males and 49,286 females).Results: A total of 1,775 patients (mean age, 49 ± 30 years) with early repolarization were chosen (1.7% of total population). The prevalence of early repolarization was about 11‐times higher in male patients (n = 1,623) than in female patients (n = 152). The prevalence of early repolarization was 1.4% at the age of 0‐9 years, peaked (5.0%) at the age of 10‐19 years, and progressively decreased with advancing age from 20 to 79 years (3.3, 2.1, 1.6, 0.9, 0.5, and 0.3% at the age of 20‐29, 30‐39, 40‐49, 50‐59, 60‐69, and 70‐79 years, respectively). Bazett's QTc interval of patients with early repolarization did not significantly differ among groups of each decade and between genders.Conclusion: The prevalence of early repolarization was both age‐ and gender‐dependent in a hospital‐based population. Yet, there was no association between QTc interval and age and between QTc interval and gender.
The Importance of the Spatial Relationship between the Position of the Non‐contact Mapping Balloon Array and the Arrhythmogenic Target Sites for Successful Catheter Ablation
Authors: Aoyagi Hideshi , Okishige Kaoru , Sugiyama Koji , Maeda Minetaka , Kurabayashi Manabu , Shimura Tsukasa , Ueshima Daisuke , Yoshimura Koujirou , Azegami Koji 
Published: August 2012

Back ground: Three‐dimensional mapping systems such as the non‐contact mapping system (EnSite) have been utilized for radiofrequency catheter ablation (RFCA) in cases with various kinds of arrhythmias.Methods: An EnSite system was utilized for RFCA in 12 patients with right‐sided atrial tachycardia (AT). The patients were classified into two groups according to the focus of the AT in the right atrium (RA). The patients in whom the EnSite array was positioned near the focus of the AT were defined as group A, whereas those patients in whom the EnSite array was located less near the focus were defined as group B. RF energy was applied under the guidance of the mapping with the EnSite array. We investigated the relationship between the position of the EnSite array and the focus of the AT in terms of the mapping accuracy in both groups.Results: Even though the accuracy of the mapping of the breakout site and arrhythmia origin was comparable between groups A and B, the distance between the successful CA sites and the presumed AT focus according to the EnSite mapping was significantly shorter in group A than group B.Conclusions: As the location of the focus of the AT becomes closer to the proximal and distal ends of the ESB, the mapping accuracy deteriorates.
Preventive Effect of Amiodarone on VT/VF Events in ICD Patients with Structural Heart Diseases
Authors: Kiryu Michiro , Niwano Shinichi , Kishihara Jun , Aoyama Yuya , Ishikawa Shoko , Murakami Masami , Kurokawa Sayaka , Yumoto Yoshihiro , Imaki Ryuta , Fukaya Hidehira , Niwano Hiroe , Izumi Tohru 
Published: August 2012

Background: Although amiodarone (AMD) is applied for implantable cardioverterdefibrillator (ICD) patients to reduce VT/VF events, its actual benefit and long‐term efficacy are unclear. In the present study, we retrospectively evaluated the incidence of VT/VF events in ICD patients with and without AMD.Methods and results: The study population consisted of 77 consecutive patients with ICD therapy and structural heart diseases. They were followed up for 24 ± 3 months, and the incidences of VT/VF events or hospitalization were evaluated. When they were divided into two groups with and without VT/VF events (42:35), univariate analysis indicated a higher incidence of cardiomyopathy as the basic disease, VT as the initial arrhythmic diagnosis, higher levels of total bilirubin, and a lower incidence of AMD use in patients with VT/VF events. When they were divided by AMD use (24/53), VT/VF events were observed in 8/24 in patients with AMD (33.3%) and 34/53 without AMD (64.2%, p = 0:012). In sub‐group analysis based on left ventricular ejection function (LVEF), the VT/VF event rate was lower in the AMD group in patients with LVEF < 40% (p = 0:007).Conclusions: AMD was considered to reduce VT/VF events in ICD patients, especially in the population with structural heart disease and lower LVEF.
Comparison of the Effects of Na+ and K+ Channel Blockers on the Electrophysiological Properties of the Pulmonary Veins in Patients with Atrial Fibrillation
Authors: Yasuda Tomoo , Kumagai Koichiro , Ogawa Masahiro , Nakashima Hideko , Zhang Bo , Miura Shin‐ichiro , Saku Keijiro 
Published: August 2012

Introduction: We assessed the effects of pilsicainide, a pure Na+ channel blocker, and nifekalant, a pure rapid delayed rectifier potassium current (IKr) blocker, on the electrophysiological characteristics within the pulmonary vein (PV) and at the PV‐left atrial (LA) junction.Methods and Results: We used a basket catheter for PV mapping in 38 patients with paroxysmal atrial fibrillation (AF). Programmed stimulation was performed in the distal PV and PV‐LA junction before and after the infusion of pilsicainide (1 mg/kg; n = 24) or nifekalant (0.3 mg/kg; n = 14). Both drugs significantly prolonged the effective refractory period (ERP) of the distal PV and PV‐LA junction. Pilsicainide significantly decreased the ERP heterogeneity of the PV and PV‐LA junction (36 ± 43 vs. 9 ± 60 ms, P < 0:05). In contrast, nifekalant significantly increased the ERP heterogeneity of the PV and PV‐LA junction (from 38 ± 34 to 60 ± 46 ms, P < 0:01). Pilsicainide significantly prolonged the conduction time (S1‐A1) from the distal PV to the PV‐LA junction (from 42 ± 12 to 63 ± 26 ms, P < 0:001), whereas this did not change with nifekalant.Conclusions: In AF patients, pilsicainide has antiarrhythmic effects mainly on the distal PV by modifying the ERP and conduction properties. In contrast, nifekalant has antiarrhythmic effects mainly on the PV‐LA junction by modifying the ERP.