bluuebunny/crossref_metadata_2025 huggingface dataset:
Long‐term Prognosis for Non‐ischemic Heart Disease Patients with Premature Ventricular Contraction and Non‐sustained Ventricular Tachycardia
Authors: Komoriya Masakazu , Imai Shinobu , Aoyama Hiroshi , Yagi Hideki , Nagashima Masaaki , Enomoto Mitsunobu , Suzuki Kazutaka , Yamaji Satoshi , Takase Hidehito , Matsudaira Kagari , Takahashi Naoyuki , Saito Fumio , Yagi Hiroshi , Kushiro Toshio , Nagao Ken , Hirayama Atsushi
Published: August 2012

There are few long‐term reports of patients with frequent PVCs in the absence of ischemic heart disease. In 86 patients without ischemic heart disease, who had 1000 or more PVCs in 24‐hour Holter ECG, the number of PVCs during 24‐hours Holter ECG and echocardiographic parameters were followed at least 1 year (66.5 ± 39.7 months). PVC was significantly reduced in the patients with or without underlying diseases (UD). The reduction rate in the number of PVCs was prominent in patients with UD. PVC was significantly reduced in patients under medication, but not in patients without medication. In the comparison between the initial and follow up observation using Wilcoxon's rank test, the number of PVC was significantly reduced (P < 0.05), and EF was also improved (P < 0.05) in angiotensin converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) group, and in β‐blocker group. In Ca‐antagonist group and antiarrhythmic drug group, the number of PVCs was also significantly reduced (P < 0.05). Multivariate analysis revealed significantly higher incidence (60% or more with PVC reduction) in ACEI/ARB group.

These results suggest that the administration of ACEI/ARB may contribute to the reduction of PVC in non‐ischemic heart disease cases with multiple PVC.
Noncontact Mapping‐Guided Catheter Ablation of Posterosuperior Right Atrial Tachycardia Associated with Sick Sinus Syndrome
Authors: Yasuda Shioto , Nakamura Hirofumi , Karashima Eiji , Ueda Jin , Nakaji Gen , Shimazu Hideki , Hiramatsu Shin‐ichi , Odashiro Keita , Maruyama Toru , Kaji Yoshikazu
Published: August 2012

Focal atrial tachycardia (AT) is sometimes associated with sick sinus syndrome. A 57‐year‐old female complained of palpitation, fatigue and presyncope. Ambulatory monitoring demonstrated frequent segments of AT and subsequent sinus arrests. P wave morphology of ectopic beats was similar to that of sinus rhythm. After obtaining diagnosis of bradycardia tachycardia syndrome, she underwent electrophysiologic study (EPS) and radiofrequency (RF) catheter ablation to eliminate AT.

Conventional EPS could not be performed due to frequent spontaneous ectopic beats. EnSite mapping demonstrated that AT originates from posterosuperior right atrium (RA) and that local electrogram of ectopic focus precedes the onset of P wave in surface ECG by 40 msec. After EnSite‐guided RF ablation to the target area, ambulatory monitoring detected no AT or sinus arrest. EPS performed one week after RF ablation showed atropine‐induced partial restoration of sinus node dysfunction.

Her symptoms were resolved remarkably and permanent pacemaker implantation has not been necessary to date. RF ablation guided by EnSite mapping was useful to eliminate AT arising from limited ectopic focus and this case implies existence of “pacemaker‐avoidable” bradycardia tachycardia syndrome.
Electrical Connections between Persistent Left Superior Vena Cava and Left Atrium during Catheter Ablation for Atrial Tachycardia
Authors: Omichi Chikaya , Kakizawa Yoshiko , Ishige Akiko , Ishii Yasuhiro , Nagashima Hirotaka , Kanmatsuse Katsuo , Endo Masahiro , Suzuki Fumio
Published: August 2012

A 74‐year‐old man presented with palpitation and 12‐lead ECG exhibited atrial premature contraction (APC) at general check‐up. Holter ECG demonstrated narrow QRS tachycardia with a rate of 160/min and more than 31,000/day atrial premature beats. The P wave morphology of atrial premature beats showed negative in II, III, aVF and biphasic in V1. Venography was performed and disclosed persistent left superior vena cava (LSVC) draining into the right atrium via the markedly dilated coronary sinus (CS). Electrogram recordings from LSVC and CS were obtained with an electrode catheter via the left subclavian vein. At the level where a ventricular potential disappeared, the intra‐LSVC potentials began to show a discrete second sharp potential after local left atrial signals. Double potentials were obtained within the LSVC from the lower left atrium (LA) to the higher LA. A proximal‐to‐distal activation sequence of the second components was observed. The interval between the 1st and 2nd component ranged from 8 to 22 msec between the proximal LSVC and distal LSVC. The double potentials resulted in fusion at the lower part of the LSVC, indicating the presence of an electrical connection between the LSVC and lower LA.
Radiofrequency Catheter Ablation with the Use of a Noncontact Mapping System for Ventricular Tachycardia Originating from the Aortic Sinus Cusp —A Case Report—
Authors: Narita Sumito , Tsuchiya Takeshi , Ashikaga Keiichi , Ushinohama Hiroya , Tanaka Yuji , Yoshinaga Masao , Kawana Hideyo
Published: August 2012

Here we present a 15‐year old female in whom an idiopathic ventricular tachycardia (VT) originating from the left aortic sinus cusp was eliminated by radiofrequency catheter ablation (RFCA) under navigation using a noncontact mapping system (NCM). The dynamic activation map constructed with the NCM clearly identified a VT focus in the left aortic sinus cusp, from which the activation spread out to the entire left ventricle. At that site, the virtual unipolar electrogram recorded with the NCM was the same as the contact unipolar electrogram in terms of morphology and timing, a pre‐systolic potential preceding the QRS complex by 40 msec was recorded by contact bipolar electrogram and rapid pacing during sinus rhythm resulted in a perfect pace match. RFCA at that site eliminated the VT and the patient has had no recurrence during 10 months of follow‐up.
Prolonged Asystole during Head‐Up Tilt Test in a Patient with Malignant Neurocardiogenic Syncope
Authors: Tokano Takashi , Nakazato Yuji , Sasaki Akitoshi , Sekita Gaku , Yasuda Masayuki , Sumiyoshi Masataka , Daida Hiroyuki
Published: August 2012

A 27 year‐old man was taken to our emergency room after collapsing during a conference. The patient had a history of syncope twice since age 15. A marked sinus bradycardia and asystole were induced causing the patient to collapse when tested to stand up in the emergency room. Cardioinhibitory type neurocardiogenic syncope was considered to be the cause of the syncope. Therefore the patient was treated with oral disopyramide at a daily dose of 150 mg. Three weeks later, a head‐up tilt test was performed for evaluation of drug effectiveness. However, a prolonged asystole for 24 seconds due to sinus arrest without escape beat was induced 7 minutes after starting the tilt at 80 degrees. Although the tilt table was returned to the flat position immediately, it took an additional 30 seconds for complete recovery of the patient's consciousness.

Malignant cardioinhibitory type neurocardiogenic syncope with a prolonged asystole such as was found in this patient has rarely been observed. Treatment options should be discussed if the patient refuses pacemaker implantation.
Radiofrequency Catheter Ablation of on‐going Persistent Atrial Fibrillation Using a Noncontact Mapping System
Authors: Ashikaga Keiichi , Tsuchiya Takeshi , Narita Sumito
Published: August 2012

We describe a 70‐year‐old man with persistent atrial fibrillation (AF) lasting for 3 months who underwent radiofrequency catheter ablation (RFCA) during on‐going AF under navigation using a noncontact mapping system (NCM). The AF was converted by the RFCA first to a secondary atrial tachycardia (AT) consisting of common atrial flutter during the left atrial (LA) roof line creation, second to a secondary AT consisting of a focal AT originating from the right superior pulmonary vein, third to a secondary AT which rotated around the LA appendage, and finally to an AT consisting of a peri‐mitral flutter after the completion of the circumferential pulmonary vein ablation and LA roof line creation. All the ATs were quickly identified by the dynamic activation map constructed with the NCM and subsequent detailed analysis of the virtual unipolar electrograms, and were eliminated by additional RFCA for each AT mechanism identified. The patient has had no recurrence during 10 months of follow‐up without taking any antiarrhythmic agents.
Catheter Ablation of Ectopic Atrial Tachycardia Originating from the Left Atrial Appendage using CARTOMERGE® System
Authors: Goya Masahiko , Hiroshima Ken‐ichi , Yasumoto Hitoshi , Niu Harushi , Soga Yoshimitsu , Ando Kenji , Nosaka Hideyuki , Nobuyoshi Masakiyo
Published: August 2012

A 70‐year‐old woman was referred because of drug resistant and daily incessant palpitation attack. She had undergone two previous unsuccessful radiofrequency catheter ablations at another hospital. The physical examination, chest X‐ray, and echocardiogram were all normal. The 12‐lead ECG during tachycardia showed narrow QRS, short PR tachycardia and negative polarity of the P wave in leads I and aVL (Fig. 1A). The ECG monitor showed incessant tachycardia with warming‐up phenomenon. Three dimensional electroanatomical map integrated with CT imaging (CARTOMERGE®, Biosense Webster Inc.) clearly revealed the radial activation pattern originating from the basalo‐postero‐inferior aspect of the left atrial appendage. Radiofrequency energy application at this site eliminated tachycardia permanently.
Transvenous Pacemaker Implantation 22 years after the Mustard Procedure
Authors: Sakamoto Masato , Ochiai Yoshie , Imoto Yutaka , Sese Akira , Watanabe Mamie , Joo Kunitaka
Published: August 2012

We implanted a permanent transvenous pacemaker to a patient with d‐transposition of the great arteries (TGA) 22 years after the Mustard procedure. The patient was a 23‐year‐old male who had undergone the Mustard procedure at one year of age. Although he was asymptomatic during regular follow‐up at our outpatient clinic until the last visit 3 months earlier, advanced atrioventricular (AV) block with sporadic complete AV block was observed. He underwent transvenous pacemaker implantation after venography for confirmation of anatomical relationship of cardiac chambers and absence of venous stenosis. The ventricular lead was anchored at the left ventricular apex, and the atrial lead was anchored at left atrial roof to avoid phrenic nerve stimulation. Screw‐in leads were selected for reliable fixation. A pacemaker with a more physiological rate response function with dual sensors was selected for the bradyarrythmia. The patient was able to resume his active daily life.
Initial Evaluation of Patients with Presumed Syncope
Authors: Can Ilknur , Benditt David G.
Published: August 2012

Syncope is a common clinical problem, but nevertheless is but one element of the broader issue of ‘transient loss of consciousness’ (TLOC). The first step is to ascertain whether the patient actually suffered a syncopal episode, and thereafter the goal must be to determine the basis of symptoms with sufficient confidence to assess prognosis and initiate an effective treatment strategy. The initial evaluation of these patients, which usually takes place in an emergency department (ED. or acute care facility, is challenging since patients are usually asymptomatic when they come for medical attention, may have little or no recall of the event, and witnesses, if any, often cannot provide reliable information. Given these circumstances, it is understandable that frontline physicians often tend to take a seemingly ‘safe’ approach, and admit both high‐risk and intermediate‐risk syncope patients to hospital. This strategy has many implications, including life‐style and economic concerns for the patient, and health care management issues for physicians, hospital administrators and the overall health care system. The European Society of Cardiology (ESC. guidelines and several clinical studies provide helpful advice regarding “risk stratification” to help guide physicians in selecting patients for either early hospital admission or later oupatient subspeciality evaluation. The utility of syncope management units in the ED, and a guideline‐based approach to the syncope patient, has tended to both diminish the number of undiagnosed cases and reduce the hospital admission rate. In this review, we have attempted to both highlight a cost‐effective diagnostic pathway beginning with the initial evaluation of the patient with suspected syncope, and to provide criteria which may help frontline physicians better base their decisions regarding need for in‐hospital versus outpatient clinic evaluation of syncope patients.
Circadian Distribution and Autonomic Tone Modulation in Paroxysmal Atrial Fibrillation
Authors: Tanabe Teruhisa
Published: August 2012

Understanding the role played by autonomic tone changes in the initiation of paroxysmal atrial fibrillation (PAF. may be helpful in preventing the occurrence of the arrhythmia. The purpose of this review article is to discuss the relationship between sympathovagal imbalance and the initiation of PAF from past literature and our data regarding circadian distribution and heart rate variability (HRV. analysis in PAF. PAF in non‐structural heart disease (NHD. frequently occurs during evening and night hours with a longer duration of each episode, and its initiation is directly associated with an increase in vagal tone. According to our data of HRV analysis in NHD, HF power (indicator of vagal tone. showed a reduction 15 to 30 minutes before PAF, followed by a sharp increase immediately before the onset, suggesting a primary increase in sympathetic tone followed by a marked changes toward vagal predominance. Very few studies have been reported on PAF onset or the modulation of autonomic tone in structural heart disease (SHD). Some studies showed no significant differences in the circadian variation of the onset between NHD and SHD. However, we demonstrated a triphasic circadian pattern with maximum peaks in early morning, late afternoon, and night in SHD, suggesting an association with not only a vagally induced origin but also a sympathecally induced or stress triggered origin in PAF onset in SHD. The occurrence of PAF greatly depends on modulation of autonomic tone and is extremely complicated. Further studies are required to clarify the relationship between the occurrence of PAF and autonomic modulation.
Current status of implantable defibrillator devices in patients with left ventricular dysfunction — The first report from the online registry database
Authors: Shimizu Akihiko , Nitta Takashi , Kurita Takashi , Imai Katsuhiko , Kimura Takeshi , Kobayashi Yoshinori , Soejima Kyoko , Niwano Shinichi , Watanabe Shigeyuki , Abe Haruhiko
Published: August 2012

Background: The current status of the efficacy of implantable cardioverter‐defibrillator (ICD. and cardiac‐resynchronization therapy with implantable defibrillator (CRT‐D. in patients with left ventricular dysfunction needs to be clarified.

Methods and Results: From the Japanese Cardiac Device Treatment Registry database, a total of 1,584 patients who had an LVEF ≦ 40% and had an ICD or CRT‐D were selected as subjects in this study. The difference in the clinical characteristics between the primary and secondary prevention groups and the transition of the indications for device implantation over time were examined. Primary prevention gradually increased up to about 50% in all patients. The implantations of ICD/CRT‐D for primary prevention in ischemic hear disease was significantly lower than that in dilated cardiomyopathy (33% vs 51%; p < 0.0001). The number of implantations for CRT‐D for primary prevention increased dramatically over a one‐year period.

Conclusions: In Japan, the implantable defibrillator devices for primary prevention was significantly lower in ischemic heart disease compared with dilated cardiomyopathy. Further, an extension of the indications for ICD/CRT‐D implantations has recently been occurring, especially with CRT‐D devices for primary prevention.
Effect of nifekalant on life‐threatening ventricular arrhythmias in patients with cardiopulmonary resuscitation or during the perioperative state
Authors: Hirasawa Shoji , Niwano Shinichi , Kishihara Jun , Kiryu Michirou , Imaki Ryuta , Izumi Tohru
Published: August 2012

Background: Nifekalant is a unique class III anti‐arrhythmic agent with a strong effect on prolonging the myocardial refractoriness, but its clinical effect is still unclear. In this study, we evaluated the effect of nifekalant on life‐threatening ventricular arrhythmias and compared the clinical background between the effective and non‐effective patients in order to clarify the clinical factors which may have an influence on the efficacy of nifekalant.

Methods: The study population consisted of 47 consecutive patients who underwent nifekalant administration for life‐threatening ventricular arrhythmias (VT/VF). Their clinical characteristics and ECG parameters were retrospectively compared between patients with and without an effective result with the nifekalant administration.

Results: Nifekalant was effective for refractory VT/VF in 26/47 patients. There was no significant difference in the age, gender or left ventricular ejection fraction, but the incidence of ischemic heart disease was higher in the effective group (17/26) than non‐effective group (9/21, p = 0.004). The incidence of in‐hospital events was higher in the effective group than non‐effective group (20/26 vs 10/21, p = 0.037). A significant prolongation in the QTc interval was observed in all patients and the degree of QTc prolongation was greater in the effective group than in the non‐effective group (0.46 ± 0.04 vs 0.43 ± 0.02 sec1/2, p = 0.026).

Conclusion: Nifekalant was effective in 55% of the patients for refractory VT/VF. It was considered that nifekalant was more effective for patients with ischemic heart disease, during the perioperative period or in those experiencing in‐hospital events. The prolongation of the QTc interval might also be useful as an index for the efficacy of nifekelant administration.
A case of unstable atrial tachycardia due to intermittent firing focus from the right inferior pulmonary vein following cavo‐tricuspid isthmus dependent atrial flutter
Authors: Kurotobi Toshiya , Ito Hiroshi , Inoue Koich , Nagai Hiroyuki , Toyoshima Yuko , Iwakura Katsuomi , Fujii Kenshi
Published: August 2012

This case report describes a patient with incessant atrial tachycardia (AT) who underwent catheter ablation. During electrophysiological study, the stable AT circuit spontaneously shifted to unstable AT due to intermittent frequent firing from the right inferior pulmonary vein (PV) after termination of cavo‐tricuspid isthmus dependent atrial flutter. A macroreentrant AT circuit was observed after electrical isolation of right inferior PV potentials. These findings suggest that the presence of rapid activated firing is likely to be associated with the development of instability in the AT circuit. This may lead to a greater understanding of the physiology of atrial tachyarrhythmia as a simple clinical model.
Reconstruction of the Right Ventricular Outflow Tract with a Transannular Patch for Ventricular Tachycardia Refractory to Radiofrequency Catheter Ablation in a Patient who Underwent Tetralogy of Fallot Surgery in Childhood
Authors: Shimane Akira , Okajima Katsunori , Mizutani Kazuo , Yoshida Masami , Imamura Kimitake , Hayashi Takatoshi , Taniguchi Yasuyo , Yamada Shinichiro , Iwata Sachiyo , Kumada Masahiro , Tsukishiro Yasue , Matsumoto Kensuke , Kurogane Yusuke , Ryo Keiko , Inoue Takumi , Kozuki Amane , Tashiro Masahiro , Kajiya Teishi , Yoshida Masato , Mizoguchi Kazuhiro , Yamanaka Katsuhiro , Mukohara Nobuhiko , Yamashiro Kouhei
Published: August 2012

A 29‐year‐old male who underwent a complete tetralogy of Fallot repair at 2 years of age was referred to our hospital for treatment of sustained ventricular tachycardia (VT). The bipolar voltage map using an electroanatomical mapping system (CARTO, Biosense‐Webster. during sinus rhythm revealed a low voltage area identical to the site of the right ventricular outflow tract (RVOT. patch on the anterior wall of the RVOT. During the tachycardia, the activation wavefront was found to revolve in a counterclockwise manner around the patch in the RVOT. Two radiofrequency catheter ablation (RFCA. sessions creating a line between the patch in the RVOT and pulmonary artery achieved only transient success. He underwent a pulmonary valve replacement and reconstruction of the RVOT with a transannular patch to treat the VT refractory to RFCA and severe pressure gradient in the RVOT. In postoperative electrophysiological study, a low voltage area in the RVOT connected to the pulmonary artery with the patch was observed, and produced conduction block in the reentry circuit of the VT. The patient has been free from any VT recurrence during 6 months of follow up.
A case of ventricular fibrillation not detected by an automated external defibrillator
Authors: Sakabe Shigetoshi , Kasai Atsunobu , Sato Yuichi , Omura Takashi , Yamanaka Takashi , Setsuda Morimichi
Published: August 2012

We report a case of ventricular fibrillation (VF) which an automated external defibrillator (AED) could not detect. A 13‐year‐old girl collapsed just after playing basketball. Cardio pulmonary resuscitation (CPR) was started immediately and 5 minutes later an AED was applied by a rescue team. The monitor of the AED displayed typical VF, but the AED did not detect it as VF. The VF was not detected during 2 more attempts. Detection occurred on the fourth attempt, and counter‐shock was successfully delivered, but the process took an extra 9 minutes. After the event, the girl was diagnosed with a latent type of prolonged QT syndrome. We analyzed the reason why the VF was not detected by the AED and found that the ECG detected by the AED fell outside the device's parameters for ventricular tachycardia (VT) or VF. We emphasize that the AED is an excellent device, but we should also be aware of its limitations.
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.
Aborted Sudden Cardiac Death Associated with Short QT Syndrome
Authors: Okishige Kaoru , Sugiyama Koji , Maeda Minetaka , Aoyagi Hideshi , Kurabayashi Manabu , Miyagi Naoto , Ueshima Daisuke , Azegami Koji , Takei Tetsuhiro , Itoh Toshitaka , Makita Naomasa
Published: August 2012

A 43‐year‐old male was transferred to our institute. His heart rhythm on admission was ventricular fibrillation (VF) which was successfully defibrillated with a direct current shock (DC). A diagnosis of short QT syndrome (SQTS) was made on the basis of an abnormally short QT interval of 280 ms during the sinus rhythm. During treatment for mild total hypothermia, VF recurred repeatedly necessitating DCs. Nifekalant at a dose of 0.3 mg/kg was intravenously administered, the QT interval was prolonged from 280 to 370 ms and VF no longer recurred. Subsequently the patient underwent implantation of an implantable cardioverter defibrillator.
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.
Catheter Ablation of Atrial Tachycardia Originating from the Tip of Right Atrial Appendage
Authors: Inoue Masaru , Matsubara Takao , Yasuda Toshihiko , Miwa Kenji , Gamou Tadatsugu , Kanaya Hounin
Published: August 2012

Right atrial appendage tachycardia is not common and can be eliminated by catheter ablation with a high success rate and low recurrence rate. However, the structural properties of the atrial appendage, including blind‐ended structure, abundant trabeculations, and reduced wall thickness could make the procedure of catheter ablation difficult, especially if the focus is at the tip of atrial appendage. We describe a case of atrial tachycardia originating from the tip of the right atrial appendage that was eliminated by catheter ablation in spite of some difficulties in manipulation of the catheter and achieving adequate radiofrequency power.
An Aggressive Strategy for Maintenance of Sinus Rhythm Including a Combination of Catheter Ablation and Antiarrhythmic Drug Therapy Benefits Patients with Chronic Atrial Fibrillation
Authors: Haruna Tetsuya , Ikeguchi Shigeru , Takeda Shinsaku , Amaya Naoki , Hata Tatsuhiko , Okada Masaharu , Kosuga Kunihiko
Published: August 2012

The effects of restoration and maintenance of sinus rhythm by a combination of catheter ablation and antiarrhythmic drugs (AADs) on atrial function in patients with chronic atrial fibrillation (AF) remain unknown. In 15 patients with chronic AF (>1 year), we attempted to restore and maintain sinus rhythm by ablation targeting complex fractionated atrial electrocardiograms (CFAEs) combined with pulmonary vein isolation with or without AADs. Sinus rhythm was restored in all patients. At 17:7 ± 7:2 months after AF ablation, maintenance of sinus rhythm was achieved in 20% of patients without AADs and in 73.3% of patients with AADs. The left atrial diameter decreased significantly by 9:5 ± 8:1% (P < 0:05) during the 12‐month followup. AADs did not have any adverse effects. The aggressive strategy for maintenance of sinus rhythm involving AF ablation and AADs potentially led to recovery of structural changes in the LA in patients with chronic AF.
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.
Epicardial Ablation of Ventricular Tachycardia with Manual Controlled External Irrigation in a Patient with Nonischemic Cardiomyopathy
Authors: Arimoto Takanori , Sekiguchi Yukio , Tada Hiroshi , Koyama Takashi , Igarashi Miyako , Yamasaki Hiro , Kuroki Kenji , Machino Takeshi , Soejima Kyoko , Aonuma Kazutaka
Published: August 2012

We describe a patient with nonischemic cardiomyopathy who underwent radiofrequency (RF) catheter ablation for a drug‐refractory ventricular tachycardia (VT). RF ablation from a left ventricular (LV) endocardial site failed to eliminate the VT. Using a conventional ablation catheter with the temperature‐controlled mode, RF ablation from the LV epicardium resulted in failed ablation because of low power due to a temperature limitation function. However, by using a pericardial pigtail catheter for manual infusion and removal of saline within the pericardial space, adequate energy could be delivered, and the ablation overlying the lowvoltage area successfully eliminated the VT.
Electro‐Anatomical Characteristics of Typical Atrial Flutter
Authors: Watanabe Ichiro
Published: August 2012

Type 1 atrial flutter (AFL) is a macroreentrant tachycardia in the right atrium; the anterior barrier of the common AFL circuit is located at the tricuspid annulus (TA) and the posterior border is functional line of block at the posteromedial (sinus venosa region) right atrium. The upper turnover site of the wave front is mainly located at the anterior to the superior vena cava. Conduction property across the posteromedial (sinus venosa region) right atrium in patients with and without AFL is different. i.e., functional conduction block occurs at the lower pacing rate in patients with AFL, and the majority of patients with chronic AFL demonstrate conduction block across the posteromedial (sinus venosa region) right atrium even during sinus rhythm. Catheter ablation therapy for AFL is creation of linear lesion between tricuspid annulus and inferior vena cava. Changes in activation sequence around the tricuspid annulus are used to confirm bidirectional block. However, it is difficult to demonstrate the bidirectional block in the presence of transverse conduction around the inferior vena cava. In such a case, bidirectional block should be confirmed by differential pacing or 3‐dimensional mapping system.
3‐D mapping of Left Atrial Conduction Pattern
Authors: Okano Yoshifumi , Igarashi Masaki , Sato Hideyuki , Fukunaga Shunji , Takamura Kazuhiro , Kobayashi Kenzaburou , Yamasaki Junichi
Published: August 2012

The purpose of this study is to examine a normal conduction pathway of the left atrium. During pulmonary vein isolation using a three‐dimensional mapping system, we observed the characteristics of the conduction pattern. Subjects consisted of 15 patients with paroxysmal atrial fibrillation (mean age, 62.8 ± 8.4 years). Left atrial activation conduction begins in the interatrial septum, and moves toward the peak of the ridge between the left atrial appendage and left pulmonary vein. In coronary sinus or appendage pacing, conduction was in the opposite direction at the same location. The mean conduction velocity in this area was 2.03 ± 0.43 m/s. Features of decrement conduction were not present. Anatomical position of the appendage differed greatly between patients. A detailed observation using the inner‐cavity view of a three‐dimensional mapping system also showed that the peak of the ridge reached the center of the roof.
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.
Characteristic Changes in Heart Rate Variability Indices during Hemorrhagic Shock, and Effect of Liposome‐Encapsulated Hemoglobin in Rats
Authors: Nogami Yashiro , Takase Bonpei , Kinoshita Manabu , Shono Satoshi , Kaneda Shinichi , Ishihara Masayuki , Kikuchi Makoto , Maehara Tadaaki
Published: August 2012

Many compensatory mechanisms exit in hemorrhagic shock (HS). To characterize the efficacy of the new artificial oxygen carrier, liposome‐encapsulated hemoglobin (LHb), HS was induced by withdrawing 20% of the total blood volume from rats. Rats received one of five interventions: LHb resuscitation (LHb‐G, n = 7), normal saline (Saline‐G, n = 7), shed autologous blood (SAB‐G, n = 7), volume expander of 5% albumin (Albumin‐G, n = 7), or no treatment (Sham‐G, n = 7). Heart rate variability (HRV) indices were measured, including low frequency (LF, 0.10–0.60 Hz), high frequency (HF, 0.60–2.00 Hz), and the ratio of LF to HF (LF/HF). LF and LF/HF following HS were lower in the LHb‐G and SAB‐G groups when compared with the Saline‐G, Albumin‐G and Sham‐G groups. LF and LF/HF following HS in the LHb‐G group were comparable with that of the SAB‐G group. These data demonstrate that HS‐induced changes can be attenuated by resuscitation with LHb as well as SAB. LHb could be used as a substitute for blood transfusion for HS.
Focal Pseudo‐Atrial Fibrillation after Radiofrequency Ablation of Focal Atrial Tachycardia
Authors: Irie Tadanobu , Kaneko Yoshiaki , Nakajima Tadashi , Saito Akihiro , Ota Masaki , Kato Toshimitsu , Iijima Takafumi , Akiyama Masahiro , Ito Toshio , Manita Mamoru , Kurabayashi Masahiko
Published: August 2012

Focal pseudo‐atrial fibrillation (AF) developed in a 30‐year‐old woman after radiofrequency (RF) ablation of focal atrial tachycardia (AT) originating from the coronary sinus ostium. Programmed atrial stimulation occasionally induced, accelerated or terminated AT, and a spiky prepotential preceded the earliest atrial electrogram at the AT focus. After the first RF application, repetitive bursts of accelerated tachycardia developed, mimicking AF on the surface ECG. An additional RF application where the spiky prepotential was observed, eliminated the focal pseudo‐AF.
A Case of Heart Failure Caused by Frequent Premature Ventricular Contractions
Authors: Sawasaki Kohei , Saito Makoto , Muto Masahiro
Published: August 2012

A 43‐year‐old woman was found to have premature ventricular contractions (PVCs) during a health check conducted 6 months ago. She was admitted to our hospital 1 month ago because of heart failure. Frequent PVCs occurring in a bigeminal or trigeminal rhythm originated from the right ventricular outflow tract (RVOT), and the total heart rate was 62,830 pulses (48%). The patient was diagnosed with heart failure caused by frequent PVCs. We performed a catheter ablation under the guidance of an electroanatomic mapping system. PVCs of 2 types were detected, and PVC1 with a notch in the inferior axis was frequently observed. Activation mapping revealed that the free wall of the RVOT was the site of earliest activation. After ablation, PVC1 and PVC2 disappeared but PVC3 and later PVC4 appeared. The notch shape of the PVCs changed. Repeat activation mapping of PVC4 showed that the earliest excited site was now the posterior wall of the right ventricle (the initial deflection preceded the QRS complex during the PVCs by 40 ms). Ablation of the posterior wall completely inhibited the PVCs. On day 3 after the ablation, the brain natriuretic peptide levels decreased from 1,294 to 86 pg/dL, indicating significant improvement in heart failure. An echocardiogram taken 3 months after discharge revealed that the ejection fraction had improved by 50–71%.
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.