Hisa Shimojima

Orexin-1 receptor immunoreactivity in chemically identified target neurons in the rat hypothalamus.

Immunohistochemistry and Western blotting were used to determine the distribution of orexin receptors in the rat brain. Strong orexin receptor 1 (OX1R) immunoreactivity was detected in the hypothalamus including the arcuate, ventromedial, and tuberomammillary nuclei that are involved in feeding regulation. The neuropeptide Y- and proopiomelanocortin-containing neurons of the arcuate nucleus, which act to stimulate or to inhibit feeding, respectively, displayed intense OX1R immunoreactivity by double immunostaining. Western blotting analysis yielded a 50-kDa major band of OX1R.

Mechanism of decrease in the atrial potential after implantation of a single-lead VDD pacemaker: atrial histological changes after implantation of a VDD pacemaker lead in dogs.

HIGASHI, Y., et al.: Mechanism of Decrease in the Atrial Potential After Implantation of a Single‐Lead VDD Pacemaker: Atrial Histological Changes After Implantation of a VDD Pacemaker Lead in Dogs. The single‐lead VDD pacemaker system (VDDPS) enables atrial synchronous ventricular pacing with only one lead in patients with an atrioventricular block. There are some cases in which the atrial potential decreases after implantation of a VDDPS, making physiological pacing difficult. The mechanism of this decrease has not been elucidated yet. To elucidate the possible relationship between the decrease of the atrial potential after implantation of a VDDPS and histopathological changes of the atrium. We implanted a VDDPS from the jugular vein under anesthesia in 10 adult dogs. The tip of the pacing lead was fixed in the right ventricular apex of the heart under fluoroscopic guidance. Then, the lead was ligated and fixed to the jugular vein at a point where a favorable atrial potential was obtained. The end of the lead was passed from the neck to the back subcutaneously; then pulled outside and fixed there to measure the atrial potential. The atrial potential was measured using a pacing system analyzer under anesthesia on days 3 (n = 9) and 7 (n = 8) , as well as on weeks2 (n = 6), 3 (n = 4), and4 (n = 3), after the implantation. The heart was removed from the dogs on day3 (n = 2), day7 (n = 2), week2 (n = 2), and week4 (n = 4)to examine the atrial histological findings. The atrial potential was2.7 ± 0.7 mVat the time of the implantation,1.7 ± 1.1 mV (P < 0.05)on day 3, and1.7 ± 0.7 mVon week 4 after the implantation. Macroscopically, the pacemaker lead was covered with thrombus, and adhered to the atrial wall in 80% of animals. Microscopically, the endocardium was hypertrophic due to fibrous tissue; besides RBC extravasation, inflammatory cells infiltration and degeneration of myocardial cells, were observed under the endocardium. Inflammatory changes developed in the atrial wall after implantation of the VDDPS, and this seemed to be one of the mechanisms for the decrease of the atrial potential of the VDDPS. (PACE 2003; 26:685–691)

Pulmonary vein isolation under direct visual identification of the left atrium—pulmonary vein junction using intra-cardiac echography

Introduction: Intra-cardiac echocardiography (ICE) which has some benefits, can be used to obtain detailed anatomy of the heart chambers or large vessels, and the catheter positions, and it has been considered useful for improving the outcome of the ablation. In the present study, we performed pulmonary vein isolation (PVI) under real time monitoring of ICE imaging utilizing an ICE catheter placed at the junction of the left atrium (LA) and PVs (LA-PV junction).Methods: PVI for atrial fibrillation (AF) was performed in 30 cases with drug-resistant AF (mean age: 66-years-old; including 22 males). An ICE catheter utilizing a 9 MHz frequency was inserted into the LA via the atrial septum, and placed at the LA-PV junction. Circumferential ablation was performed in the LA outside of the PV ostium, encircling both the superior and inferior ostia together under ICE imaging.Results: The anatomy of the LA to the PVs and catheter sites were clearly identified by the ICE during the procedure, which enabled a precise and safe catheter manipulation with minimal fluoroscopy. Further, the wall thickness of the PV and LA, and position of the esophagus could be obtained by ICE, facilitating care in adjusting the power and/or duration of the current delivery.Conclusion: ICE imaging of the LA-PV junction permitted real time monitoring of the target sites for PVI during the ablation procedure, and was considered a useful technique for performing PVI.

A Case With Apical Hypertrophic Cardiomyopathy, Multiple Coronary Artery–Left Ventricular Fistulae, and a Morphological Structure Mimicking Left Ventricular Noncompaction Statue of Cerberus or Double-Headed Eagle?

Multiple coronary fistulae that drain into the left ventricle are rarely associated with apical hypertrophic cardiomyopathy.1 On the other hand, associations of left ventricular noncompaction (LVNC) and multiple coronary fistulae or hypertrophic cardiomyopathy have previously been reported in several cases.2,3 We report here a unique case of apical hypertrophy of the left ventricle, multiple coronary–left ventricular fistulae, and a morphological structure of the left ventricular myocardium mimicking LVNC. A 59-year-old man was admitted to our hospital for fever and rapidly progressing dyspnea that had persisted for 10 days. He had been diagnosed with apical hypertrophic cardiomyopathy in his 30s, although he had no regular medical checkups and was asymptomatic. On admission, the patient had mild wheezes audible in the midportion of the right lung and a diastolic murmur heard at the Erb and the cardiac apical area. Chest x-ray and computed tomography revealed cardiac enlargement with increased pulmonary vasculature, granular shadows in the lower areas of both lungs, and increased density of the right middle lung area. These findings suggested failure of the left side of the heart with pneumonia. A 12-lead electrocardiogram (ECG) …

A Case of Transient Rise of Pacing Threshold during the Chronic Phase of Pacemaker Implantation

We experienced a case of pacing failure with transient rise of the pacing threshold more than one year after implantation. Neither the generator nor lead system was found to be defective. During the antibiotics therapy to treat cholecystitis, which was found on admission, pacing failure was improved. The clinical course suggested that the infection was related to the improvement, although accurate mechanisms were unknown.

A Case With Pulmonary Vein Stenosis and Obstruction After Pulmonary Vein Isolation: A Multimodality Approach

Pulmonary vein stenosis and occlusion are some of the major complications after radiofrequency ablation of atrial fibrillation. The prevalence of pulmonary vein stenosis and pulmonary vein occlusion decreased remarkably after the advent of area circumferential ablation and antral isolation; however

Cardiac Sarcoidosis Mimicking Septal Tumor with Intermittent Complete Atrioventricular Block

A 52-year-old woman with intermittent complete atrioventricular (AV) block detected on exercise was admitted to the hospital. Echocardiography revealed lesions on the right ventricular side of the interventricular septum and free wall of the basal inferolateral area. Gadolinium-enhanced cardiovascular magnetic resonance (CMR) imaging revealed the mass and wall thickening at the same locations with late gadolinium enhancement (LGE). Focal uptake at the septal lesion was detected using 67Ga scintigraphy. Focal on diffuse intense uptake in the lesions was observed on Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) imaging. Whole-body CT and laboratory evaluations uncovered no signs of malignant tumors in other organs. Ophthalmologic evaluation revealed ophthalmologic sarcoidosis. Although the result of endomyocardial biopsy was negative, the presence of cardiac sarcoidosis was strongly suggested on the basis of the new Japanese guidelines published in 2017. AV conduction disturbance and tracer accumulation on 67Ga scintigraphy completely disappeared after 2 weeks of steroid therapy. The size of mass, inferolateral wall thickness in echocardiography and CMR, and standardized uptake value (SUV) of the masses on 18F-FDG PET also decreased over time.

Sudden cardiac arrest during marathon training in a young adult with short QT syndrome

A variety of mostly hereditary, structural, or electrical cardiac disorders are associated with sudden cardiac death in young athletes and amateur sport participants [1]. Short QT syndrome (SQTS), a condition first described in 2000 [2], is a rare cardiac channelopathy characterized by abnormally short cardiac repolarization. Data from only a small group of patients identified worldwide are available. The annual risk of cardiac arrest among patients in the largest SQTS cohort to date was approximately 1%, and most of the cardiac arrests reported in the cohort occurred during rest or sleep [3]. Risk stratification and management of SQTS remain uncertain, however, as data on the natural history of SQTS are lacking. Here we report a patient with SQTS who suffered a sudden cardiac arrest when marathon training.

Isolation of the conduction between the Marshall bundle and distal coronary sinus and the entire coronary sinus for an atrial tachycardia after catheter ablation of atrial fibrillation

Introduction Even though mitral isthmus block is completely achieved after pulmonary vein (PV) isolation for atrial fibrillation (AF) by adding a linear ablation, in some cases atrial tachycardias (ATs) can occur that break through between the left atrial appendage and left PVs. This type of perimitral flutter has been reported as a ridge-related reentry (RRR). Jiang and colleagues speculated that one of the mechanisms for the appearance of this RRR tachycardia could be reentry through the vein of Marshall (VOM). In a previous report, an AT through the VOM was diagnosed by passing a thin catheter though the VOM and ablating it from the left atrial endocardium. In this report, we describe a novel method of diagnosing and ablating an AT through the VOM.

Left ventricular function and myocardial perfusion before and after cardiac resynchronization therapy in chronic right ventricular apical pacing by echocardiogram-gated myocardial perfusion single photon emission computed tomography

The aim of this study was to evaluate the changes in cardiac performance and myocardial blood perfusion by single photon emission computed tomography (SPECT) in patients upgrading to cardiac resynchronization therapy (CRT) from right ventricular apical pacing (RVAP).