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Biomedical subjects

H Sakurada

Publications and source records attributed to H Sakurada.

At least 37 records · Page 2Linked to original sources
PubMed1997

Demonstration of Purkinje potential during idiopathic left ventricular tachycardia: a marker for ablation site by transient entrainment.

During VT of QRS morphology with right bundle branch block and left axis deviation in a patient without obvious structural heart disease, entrainment by pacing from the right ventricular outflow tract and high right atrium was demonstrated. During entrainment of VT, a Purkinje potential preceding the QRS and recorded at the left ventricular mid-septum was activated by orthodromic impulses in the reentry circuit. The interval between the Purkinje potential and the earliest left ventricular activation was decrementally prolonged with shortening of pacing cycle length. Radiofrequency energy was applied to this site, resulting in successful elimination of VT. Therefore, the Purkinje potential represented activation by an orthodromic wavefront in the reentry circuit, while the orthodromically distal site to this potential showed an area of slow conduction with decremental property.

Adult↗
PubMed1996

Induction of polymorphic ventricular tachycardia by programmed ventricular stimulation in vasospastic angina pectoris.

This study was designed to examine the ventricular vulnerability of patients with vasospastic angina. Fourteen patients (mean age 57 +/- 9 years) with vasospastic angina underwent electrophysiologic testing during the asymptomatic phase (baseline) and after the relief of acetylcholine-induced spasm with isosorbide dinitrates. Twenty patients without structural heart disease served as a control group. By programmed ventricular stimulation, polymorphic ventricular tachycardia (VT) was induced at baseline in 6 of 14 patients, with 1 patient developing ventricular fibrillation and 7 of 14 patients developing repetitive ventricular responses. After isosorbide dinitrate, polymorphic VT was induced in only 1 patient who had ventricular fibrillation at baseline. Repetitive ventricular responses were induced in 3 of 5 patients who had VT at baseline and in 4 of the 7 patients with repetitive ventricular responses at baseline. There was a significant difference in the incidences and severity of induced ventricular arrhythmias between the 2 phases (p <0.01). Among 20 control subjects, repetitive ventricular responses were induced only in 6 patients, but no VT was induced. There was a significant difference in the incidence of induced ventricular arrhythmias and VT at baseline between the vasospastic angina and control groups (p <0.001 and <0.01, respectively). Thus, patients with vasospastic angina had increased ventricular vulnerability, even during the symptom-free period without ischemic events, which could predispose to the development of life-threatening arrhythmias aggravated by vasospastic attacks.

Adult↗
PubMed1996

Malignant fibrous histiocytoma of the esophagus.

A 78-year-old man presented with an esophageal polyp that was confirmed by immunohistochemistry and electron microscopy to be malignant fibrous histiocytoma. The tumor was comprised of a proliferation of spindle-shaped cells admixed with bizarre giant cells. These tumor cells were immunoreactive for smooth muscle actin, vimentin, alpha-1-anti-chymotrypsin and CD68. Electron microscopic examination revealed the myofibroblastic and histiocytic features of the tumor cells. No elements of epithelial or myogenic differentiation were found in the tumor. Malignant fibrous histiocytoma of the esophagus is extremely rare, with 10 cases being documented so far in the literature. The differential diagnosis of pleomorphic tumors of the esophagus is discussed.

Aged↗
PubMed1996

Catheter ablation for the common type of atrioventricular nodal reentrant tachycardia.

Radiofrequency (RF) catheter ablation of the slow AV nodal pathway was attempted in 34 patients with common type of AV nodal reentrant tachycardia (AVNRT). Radiofrequency energy of 18-32 watts was applied for 30-60 seconds at sites exhibiting atrial-slow pathway potentials or slow potentials. These potentials were recorded at the mid or posterior septum, anterior to the coronary sinus ostium. A mean of two radiofrequency applications successfully eliminated AVNRT in all patients. The incidence of junctional ectopy was significantly higher during 34 effective applications of radiofrequency energy than during 36 ineffective applications (100% versus 17%). Thus, the recording of atrial-slow pathway potentials or slow potentials, and the development of junctional ectopy can be used as a marker for successful ablation. Slow AV nodal conduction was eliminated in 22 patients and persisted without inducible AVNRT in 12. None of the patients had recurrences of AVNRT over a mean follow-up interval of 12 months, and all had preserved AV conduction. Long-term follow-up studies with an electrophysiological method confirmed that the ablation was effective. Transient AV block was observed in only 1 patient, and no major complications were noted. Thus, radiofrequency catheter ablation of the slow AV nodal pathway is highly effective and safe, with a low rate of complication, for the treatment of common type of AVNRT.

Adult↗
PubMed1996

[A case of giant hepatocellular carcinoma successfully treated by arterial administration of SMANCS].

A 68-year-old male was referred to our hospital for the precise examination of a giant hepatic tumor detected in a mass survey. The lesion occupied most of the right hepatic lobe, further advancing to the medial segment of the left lobe. However, hepatic functions were well preserved (ICG K = 0.141). Considering the characteristic images of the lesion with positive anti-HCV and high titer of PIVKA II (0.860 AU/ml), the diagnosis was hepatocellular carcinoma. First arterial administration of SMANCS was performed on May in 1994, followed by 6 successive procedures with an interval of about 2 months (total dosage 36 mg), resulting in remarkable tumor shrinkage and tumor marker normalization. On January in 1995, a metastatic lesion to the right rib was controlled by 2 mg of SMANCS administered to the intercostal artery combined with radiation therapy (60 Gray). Frequent administrations of SMANCS caused no serious complications, and tumor feeders were well preserved. Therefore, arterial administration of SMANCS is thought to be one choice for the therapy of giant HCC with good functional reserve.

Aged↗
PubMed1996

[Tricuspid and mitral regurgitation due to congenital hypoplasia of atrioventricular valves in the aged: a case report].

A 76-year-old woman with a history of repeated right-sided cardiac failure during the past 2 years presented with tricuspid and mitral regurgitation due to congenital hypoplasia of atrioventricular valves. Two-dimensional echocardiography demonstrated enlarged right atrium and right ventricle, and discoaptation between the leaflets. Color Doppler echocardiography revealed severe tricuspid regurgitation through the gap between the leaflets. Autopsy showed congenital hypoplasia of the leaflets and the chordae tendineae in the tricuspid and mitral valvular apparatus.

Aged↗
PubMed1995

Long-term follow-up of the reproducibility of carotid sinus hypersensitivity in patients with carotid sinus syndrome.

The reproducibility of carotid sinus hypersensitivity to carotid sinus massage was studied in the long-term follow-up of 8 patients with carotid sinus syndrome. A cardioinhibitory response was induced in 7 patients, while a vasodepressor response was found in the remaining patient. The 7 patients were treated with dual-chamber pacemaker implantation and the remaining patient was treated with propranolol. All of the patients remained asymptomatic during a follow-up period of 48 +/- 11 months. Carotid sinus massage during the follow-up period in patients with a cardioinhibitory response revealed asystolic intervals of 3 s or longer in 4 patients and in 3 patients at the second and third follow-up examinations, respectively, although there were no significant differences in the ventricular asystolic intervals between before, and 34 +/- 11 months and 48 +/- 11 months after treatment. However, each patient showed a wide variation in asystolic intervals. The differences in asystolic intervals between prior to treatment (first) and the third test were significantly greater than those between the first and the second test (2.4 +/- 1.2 s vs 0.7 +/- 0.6 s; p < 0.05). The one patient with a vasodepressor response had a decreased systolic blood pressure greater than 50 mmHg by carotid sinus massage at all three occasions. In conclusion, most patients with carotid sinus syndrome showed abnormal and variable responses to carotid sinus massage during long-term follow-up period although there was no recurrence of symptoms after treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Clinical evaluation of lansoprazole in the treatment of peptic ulcers: initial healing and prevention of relapse. Tohoku Peptic Ulcer Study Group.

The clinical usefulness of lansoprazole in the healing of gastric and duodenal ulcers, the S2-stage shift rate (white scarring rate), and endoscopic healing rate with respect to degree of gastric mucosal atrophy were investigated. The subjects were 50 gastric ulcer and 37 duodenal ulcer patients. The endoscopic healing rate in patients with gastric ulcers after initial treatment with lansoprazole was 92% after 8 weeks. The S2-shift rate was 38% after 8 weeks. The 8-week healing rate in patients without atrophy was 100% and with atrophy was 92%, although the difference was not statistically significant. The S2-shift rate in patients without atrophy was 42% and in patients with atrophy was slightly lower, at 37%, although the difference was not statistically significant. The endoscopic healing rate in patients with duodenal ulcers was 93% after 6 weeks, and the S2-shift rate was 59%. It is firmly established that atrophic gastric mucosa shows a reduction in mucosal defense factors. However, lansoprazole achieved good endoscopic healing rates and S2-shift rates even in patients with gastric ulcers with atrophic background mucosa.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1994

Generation of active oxygens, cell deformation and membrane potential changes upon UV-B irradiation in human blood cells.

The generation of peroxides (presumably hydrogen peroxide) by UV-B irradiation of human blood cells was detected. Non-fluorescent dihydrorhodamine 123 (DHR) is oxidized to fluorescent rhodamine 123 (R123) by H2O2 or peroxides with a stoichiometry of 1:1 in the presence of exogeneous peroxidase, and the fluorescence of R123 within the cells was measured using flow-cytometry. UV irradiation gave rise to changes in the cellular volume and the membrane potential, whose extent and direction were dependent on the type of blood cells. The production of peroxides (H2O2) in polymorphonuclear leukocytes is the largest among blood cells at the lower dose (< 0.1 J/cm2), and the production decreases with an increase in the dose, while the production in platelets is the smallest at the lower dose, but above 0.4 J/cm2 it increases suddenly so that at the higher dose (1.2 J/cm2) it amounts to 3.3 x 10(-16) mol/cell. For monocytes and lymphocytes, the production increases gradually with the increase in the dose.

Blood Cells↗
PubMed1993

Factors for transient entrainment of ventricular tachycardias by rapid atrial pacing.

Thirteen patients with sustained ventricular tachycardia (VT) were studied to elucidate predisposing factors for the development of constant and progressive fusion by rapid atrial pacing. All patients demonstrated transient entrainment by rapid ventricular pacing during VT. Constant and progressive fusion were observed in 7 patients (positive group) during rapid atrial pacing, but not in 6 (negative group). In the positive group, VT was induced by atrial pacing in 2 patients. The demonstration of constant and progressive fusion by atrial pacing was not dependent on QRS morphology or ventriculoatrial conduction during VT. VT cycle length in the positive group (363 +/- 59 ms) was longer than in the negative group (297 +/- 31 ms; p = 0.033). The maximal atrial pacing rate producing 1:1 atrioventricular (AV) conduction in the positive group was 171 +/- 18 beats/min compared with 125 +/- 22 beats/min in the negative group (p = 0.002). There were distinct differences between the positive and negative groups in the ratio of VT cycle length to minimal atrial cycle length causing 1:1 AV conduction (1.02 +/- 0.12 vs 0.61 +/- 0.12; p = 0.0001). It is concluded that AV conduction, VT cycle length and especially their ratio are important factors for the development of transient entrainment by rapid atrial pacing during VT. Therefore, atrial pacing can be used as an easy and useful method to examine transient entrainment during VT.

Adult↗
PubMed1992

Double ventricular responses to a single atrial depolarization in a patient with dual AV nodal pathways.

Electrophysiological study was performed in a patient with atrioventricular nodal reentrant tachycardia (AVNRT). Double ventricular responses through dual AV nodal pathways were observed by atrial extrastimulus technique followed by initiation of AVNRT. The difference in conduction time between the slow and fast AV nodal pathways was longer than 320 msec. A ventricular extrastimulus delivered during sinus rhythm, which was not followed by ventriculoatrial conduction, also induced AVNRT. These findings indicated the presence of an antegrade critical delay and retrograde block in the slow AV nodal pathway, criteria necessary for the occurrence of a double ventricular response.

Adult↗
PubMed1991

Efficacy of disopyramide and mexiletine used alone or in combination in the treatment of ventricular premature beats.

The efficacy of oral disopyramide and mexiletine used alone or in combination was studied in 75 patients with frequent ventricular premature beats (VPBs). The efficacy was evaluated with 24-hour ambulatory ECG and greater than or equal to 75% reduction in the number of VPBs was defined as effective. When disopyramide or mexiletine were ineffective or not tolerated, the alternative drug was administered and the efficacy was again evaluated. If the single administration of neither drug was effective, the combination of disopyramide and mexiletine was then given. Either disopyramide or mexiletine was effective in 48 patients, and neither drug was effective in 19 patients. In 19 patients unresponsive to both drugs, combination therapy was effective in six patients (32%). Both drugs caused side effects or one drug caused side effects and another drug was ineffective in eight patients. In five out of those patients, we attempted combined therapy with a reduced dosage of those drugs that caused side effects. This therapy was effective in two patients without intolerable side effects. Thus, when the single use of neither disopyramide nor mexiletine single-drug therapy is effective, it is worthwhile to try combination therapy. Also, combination therapy with a reduced dosage of the drugs that caused side effects might be the therapy of choice in patients who have developed dose-dependent side effects.

Adult↗