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Biomedical subjects

Haruhiko Abe

Publications and source records attributed to Haruhiko Abe.

At least 37 records · Page 2Linked to original sources
PubMed2003

Successful treatment of radiation-induced brain necrosis by hyperbaric oxygen therapy.

We describe a 68-year-old man who underwent hyperbaric oxygen (HBO) therapy to manage radiation necrosis of the brain, which developed after two treatments with stereotactic radiosurgery (SRS) to the same lesion. The necrosis was subsequently treated with steroids alone for 2 months; however, he progressed clinically and radiographically. Improvement again was noted with the reinstitution of HBO therapy. This case suggests that HBO therapy is an important therapeutic option in the treatment of brain radiation necrosis caused by SRS.

Aged↗
PubMed2003

Clinical advantage of neutral anode positioning feature in recent pacemaker generator.

Recent advances in pacemaker technology such as a thinner lead body, smaller size of pacemaker generators and pacemaker pulse generators with the neutral anode positioning (NAP) feature, have made pacemaker implantation easier. To date, however, the clinical disadvantages of this NAP feature have not been investigated. We investigated whether there are any clinically disadvantages in pacing and sensing thresholds, myopotential tracking thresholds and myopotential inhibition thresholds in 62 pacemaker patients with the NAP feature. All measured data from the NAP devices when the pacemaker was set to the bipolar system were acceptable and normal. In the unipolar system with NAP feature, no differences were observed in the numerous parameters measured compared to previously reported measured data in the unipolar system without the NAP feature. We concluded that the physician can also benefit from this feature since any pulse generator with the NAP feature is suitable for implant on either side of the body, without any disadvantages. Therefore, left- or right-sided pacers need no longer be ordered, stocked, or specified at the time of implant.

Cardiac Pacing, Artificial↗
PubMed2003

Analysis of transmural trends in myocardial integrated backscatter in patients with progressive systemic sclerosis.

Cardiac involvement in progressive systemic sclerosis (PSS) is common and has a strong negative impact on the prognosis, especially when autoantibodies are present. To determine whether ultrasonic tissue characterization can detect early ultrastructural changes in the sclerodermal myocardium, we analyzed the transmural heterogeneity in myocardial integrated backscatter (THIB). "A-THIB" was defined as the absolute difference in integrated backscatter between the left (subendocardial) and right (subepicardial) ventricular halves of the myocardium in the septum and posterior wall, and was measured in 11 patients with PSS and 10 age- and sex-matched healthy participants. A-THIB in patients with PSS was higher than that in healthy participants (1.3 +/- 1.3 vs 4.0 +/- 1.4 dB for the septum and 1.1 +/- 0.7 dB vs 2.8 +/- 0.4 dB for the posterior wall; mean +/- SD, respectively, P <.0005). Septal A-THIB was higher in patients with PSS with than without anti-Scl70 or antinucleolar antibodies (3.2 +/- 1.1 vs 5.0 +/- 1.0 dB, P =.0165). Early changes in the myocardium of patients with PSS, possibly related to increased interstitial collagen deposition, can be detected by quantitative analysis of THIB.

Adult↗
PubMed2003

Successful treatment of severe orthostatic hypotension with erythropoietin.

A 71-year-old man, who was diagnosed with familial amyloidosis type I, was admitted for treatment of severe orthostatic hypotension associated with recurrent syncopal attacks. Head-up tilt testing demonstrated severe orthostatic hypotension (114/72 mmHg in the supine position and 62/34 mmHg in the upright position) with syncope or presyncope. Oral midodorine and fludrocortisone therapies failed to prevent his symptoms. After administration of subcutaneous erythropoietin, his blood pressure drop in the upright position was decreased and symptoms disappeared unassociated with improvement of anemia. Although previous reports have shown that the mechanism by which erythropoietin improves orthostatic hypotension is related to improvement in anemia, other mechanisms may also play a role.

Aged↗
PubMed2003

Sustained polymorphic ventricular tachycardia unassociated with QT prolongation or bradycardia in the Kearns-Sayre syndrome.

Cardiac dysfunction, including congestive heart failure and impulse conduction abnormalities, have been implicated in the sudden death of patients suffering from the Kearns-Sayre syndrome. This report describes a 29-year-old woman who suffered syncopal episodes due to sustained polymorphic VT. Sustained polymorphic VT was not associated with prolongation of the QT interval or bradycardia on the ECG. The implantation of a cardioverter defibrillator should be considered in this syndrome.

Adult↗
PubMed2003

Microdislodgment: a likely mechanism of pacing failure with high impedence small area electrodes.

High impedance tined steroid-eluting leads, Medtronic CapSure Z family, incorporating a small surface (1.2 mm2) electrode made of porous platinum material are designed to reduce battery current drain. However, in some prior studies, an increased incidence of microdislodgment with this lead was reported thought to be due to the reduced electrode surface area. This article reports the experience that ventricular pacing failure due to microdislodgment occurred after CapSure Z lead implantation and the previous literature is reviewed. (

Aged↗
PubMed2003

Effects of orthostatic self-training on head-up tilt testing for the prevention of tilt-induced neurocardiogenic syncope: comparison of pharmacological therapy.

Although a wide variety of medical treatments for neurocardiogenic syncope have been proposed, therapy has largely been emperic based on the mechanisms commonly believed to lead to neurocardiogenic fainting. To determine the utility and efficacy of drug therapy and an orthostatic self-training program in the prevention of tilt-induced neurocardiogenic syncope, we investigated 43 consecutive patients who had shown syncope and were induced by head-up tilt test reproducibly, with either traditional medical treatments or orthostatic self-training at home. The initial 19 of 43 patients were treated with either oral propranolol or disopyramide therapies. The remaining 24 patients were treated with an orthostatic self-training program alone. Effects of these therapies on head-up tilt test were reevaluated in all patients. Propranolol prevented syncope in only six (32%) and disopyramide in five (26%) of the 19 patients. There was no significant difference in the effectiveness between them. Syncope was prevented in nine (47%) patients with either propanolol or disopyramide therapy alone, while in the remaining 10 patients it was not. On the other hand, orthostatic self-training program prevented syncope in 22 (92%) of 24 patients. We concluded that orthostatic self-training program is far more effective than traditional drug therapies. Orthostatic self-training is an effective, safe and well accepted therapy in the prevention of tilt-induced neurocardiogenic syncope.

Adult↗
PubMed2003

Efficacy of orthostatic self-training in medically refractory neurocardiogenic syncope.

BACKGROUND: Orthostatic self-training is effective in the prevention of neurocardiogenic syncope, though the success of this method in drug refractory patients has not been reported. STUDY OBJECTIVE AND METHODS: This study examined the effectiveness of orthostatic self-training in 15 patients with head-up tilt testing (HUT)-inducible neurocardiogenic syncope, who were intolerant of, or refractory to standard drug therapy. They were enrolled in a home orthostatic self-training program for up to 30 min/session, twice daily. Head-up tilt testing was repeated within 4 weeks after onset of the training program, using the same protocol as at baseline. Orthostatic self-training was continued once daily, for up to 30 min, for a mean follow-up period of 11 months, in the drug-free state. RESULTS: Syncope was not reinducible by follow-up HUT, and spontaneous syncope occurred in no patient during the follow-up period. CONCLUSIONS: Home orthostatic self-training, up to 30 min once daily following an initial twice daily program, was highly effective in the suppression of recurrent neurocardiogenic syncope in patients intolerant of, or refractory to standard drug therapy.

Adult↗
PubMed2003

What is the optimal increase in resting heart rate with low dose isoproterenol infusion for tilt-induced vasovagal response?

Isoproterenol is widely used as a provocative medium for vasovagal responses during tilt testing. Dose of isoproterenol infusion is generally titrated empirically by increase in resting heart rate before tilt up. To determine the optimal increase in resting heart rate with isoproterenol for tilt-induced vasovagal responses, we studied 97 consecutive patients with unexplained syncope. After the end of a negative baseline tilt (80 degrees for 30 min), the isoproterenol tilt was performed using one of two protocols: two-stage isoproterenol-tilt protocol, with doses of 0.01 and 0.02 microg/kg per min for 10 min each, or one-stage isoproterenol-tilt protocol, with a dose of 1 or 2 microg/min for 10 min. The resting heart rate increase was defined as a percentage increase in the resting heart rate after isoproterenol infusion, compared to the baseline heart rate before the tilt test. In 117 tilt procedures, 28 (93%) of the 30 positive responses occurred with a resting heart rate increase of > or = 21%. With the resting heart rate increase of 60 and 100%, 18 (60%) and 27 (90%) positive responses were observed, respectively. In conclusion, the minimum resting heart rate increase of > or = 21% was required to provoke a vasovagal response during subsequent isoproterenol-tilt (80 degrees for 10 min). Preferably, heart rate should be increased to 60-100% by isoproterenol titration before tilting.

Adult↗
PubMed2003

[Central nervous system involvement in patients with decompression illness].

Dysbarism or decompression illness (DCI), a general term applied to all pathological changes secondary to altered environmental pressure, has two forms decompression sickness (DCS) and arterial gas embolism (AGE) after pulmonary barotrauma. Cerebral and spinal disorders have been symptomatically categorized as AGE and DCS, respectively. Magnetic resonance images (MRIs) of divers with DCI showed multiple cerebral infarction in the terminal and border zones of the brain arteries. In addition, there were no differences between MRI findings for compressed air and breath-hold divers. Although the pathogenesis of the brain is not well understood, we propose that arterialized bubbles passing through the lungs and heart involved the brain. From the mechanisms of bubble formation, however, this disorder has been classified as DCS. We propose that there is a difference between clinical and mechanical diagnoses in the criteria of brain DCI. In contrast to brain injury, the spinal cord is involved only in compressed air divers, and is caused by disturbed venous circulation due to bubbles in the epidural space. The best approach to prevent diving accidents is to make known the problems for professional and amateur divers.

Central Nervous System↗
PubMed2003

Effects of orthostatic self-training on head-up tilt testing and autonomic balance in patients with neurocardiogenic syncope.

To investigate the effectiveness and the mechanisms of an orthostatic self-training program for the prevention of neurocardiogenic syncope, 28 patients were treated with an orthostatic self-training program. Syncope was induced by head-up tilt testing (+ 80 degrees for 30 min) in all patients. The onset time of the tilt-induced syncope was 14 +/- 7 min following placement in the upright position. The orthostatic self-training program included standing against a wall without moving twice a day every day for a planned duration of up to 30 min at home. The head-up tilt response was re-evaluated after 24 +/- 6 days based on results of the self-training. In 12 of the 28 patients, the sympathovagal balance was also determined during the head-up tilt test before and after the training with power spectral analysis of heart rate variability using a maximal entropy method. Syncope was not observed in any patient after the training. Although the low frequency/high frequency ratio in the supine position was not different before and after the training, the ratio after 3 min in the upright position after the training decreased significantly compared with that before the training. High-frequency components in the supine and upright positions were not different before and after the training. We concluded that orthostatic self-training significantly improved symptoms in patients with tilt-induced neurocardiogenic syncope. Decreased sympathetic activity in the early stage of the upright position period may play an important role in the mechanisms of this therapy.

Adult↗
PubMed2002

Reproduction of typical electrocardiographic findings of the Brugada syndrome using modified precordial leads.

We present a case of a patient with Brugada syndrome and aborted sudden cardiac death in whom the typical Brugada sign (coved-type ST segment elevation in the precordial leads V1 through V3) was always reproduced by the precordial leads recording on the second intercostal space even after the typical sign had disappeared. The finding indicates that recordings of precordial leads on the higher intercostal spaces are important to unmask the ST elevation in suspected patients with Brugada syndrome.

Bundle-Branch Block↗
PubMed2002

Recent advances in implantable cardioverter defibrillator systems.

The usefulness of the implantable cardioverter defibrillator (ICD) for the prevention of sudden cardiac death caused by ventricular tachyarrhythmias has been proven by several international randomized multi-center clinical trials. Recent advances in medical technologies, such as size reduction and the functional improvements of the device, have resulted in relatively easy implantation. As a result, the number of ICD recipients has been rapidly increasing and the indications for ICD implantation have been expanding. Dual chamber ICDs offer improved tachyarrhythmia detection algorithms such as discrimination of supraventricular arrhythmias. In Europe and the United States, biventricular ICDs are now available for the treatment of congestive heart failure associated with ventricular tachyarrhythmias. Although the incidence of inappropriate shock by ICDs is decreasing, inappropriate discharges of ICDs and a declining quality of life are still problems.

Clinical Trials as Topic↗
PubMed2002

[Successful hybrid therapy combined with oral bepridil and ICD in a patient with amiodarone refractory life-threatening ventricular tachyarrhythmia associated with ischemic cardiomyopathy].

A 68-year-old man was admitted to our hospital for the treatment of angina and ventricular tachyarrhythmia. A coronary and left ventricular angiography showed coronary artery disease and ischemic cardiomyopathy with severe left ventricular dysfunction. A percutaneous transluminal coronary angioplasty was performed successfully in the right coronary artery and his angina symptoms disappeared. However, ventricular tachycardia (VT)/ventricular fibrillation (VF) occurred spontaneously and converted to sinus rhythm with direct current shock (300 J). Oral amiodarone (200 mg/day) and continuous intravenous infusion of nifekalant and lidocaine were started. In addition, a dual chamber implantable cardioverter defibrillator (ICD) for his VT/VF was implanted. However, VT/VF occurred repeatedly after discontinuation of nifekalant. After the administration of bepridil (200 mg/day), VT/VF was completely prevented without nifekalant administration. The hybrid therapy with ICD and oral bepridil is very useful for the treatment of amiodarone resistant ventricular tachyarrhythmia.

Administration, Oral↗
PubMed2002

Rate-dependent QT shortening mechanism for the LQT3 deltaKPQ mutant.

OBJECTIVE: For the congenital long QT (LQT) syndrome involving mutations of the cardiac sodium channel gene SCN5A, LQT3, the initiation of sudden cardiac death tends to be bradycardia- or pause-dependent, contrary to other LQT syndromes that tend to be adrenergic dependent. Enhanced shortening of the prolonged QT interval with increased heart rate has been reported in LQT3 patients. We hypothesized that the rate-dependent shortening of the QT interval may be attributed to the kinetic properties of inactivation the late sodium current (I(Na)) in LQT3. METHODS: The deltaKPQ mutant of the human heart voltage-gated sodium channel alpha-subunit was stably transfected into a mammalian cell line (HEK293). I(Na) was recorded using a whole-cell patch-clamp technique. RESULTS: A train of 50 depolarizing pulses or a train of 50 ventricular action potential waveforms was applied with different interpulse durations. Peak I(Na) for the 50th pulse compared with that of I(Na) in the first pulse was decreased <2% for interpulse durations as short as 20 ms, but late I(Na) amplitude measured at the end of the pulse was decreased 95, 78, 68, 56 and 47% with 1000, 500, 200, 100, 20 ms interpulse intervals, respectively. Using the action potential waveform a similar rate-dependent reduction of late I(Na) was found with minimal reduction of peak I(Na). CONCLUSIONS: Late I(Na) amplitude in the deltaKPQ mutation is strongly rate dependent. Rate-dependent reductions of late I(Na) may cause shortening the QT interval at higher rates. This provides a mechanism correlating the genotype with the clinical phenotype, and provides a rationale for the effectiveness of pacemaker therapy in LQT3 patients.

Action Potentials↗
PubMed2002

Right pneumothorax resulting from an endocardial screw-in atrial lead in an implantable cardioverter defibrillator system.

This report describes a rare case of a patient undergoing implantation of a cardioverter defibrillator in whom a right pneumothorax resulting from an endocardial screw-in atrial lead was observed. Pericardial effusion, substantial changes in lead impedance, andpacing and sensing thresholds were not observed. Pneumothorax disappeared spontaneously and has not reoccurred during follow-up with conservative therapy alone.

Adult↗