Biomedical subjects

Takeshi Arita

Publications and source records attributed to Takeshi Arita.

6 recordsLinked to original sources

PubMed2006

Intracoronary stent visualized on transesophageal echocardiogram in a case of coronary dissection complicated by aortic dissection.

We present a case of a patient presenting with a myocardial infarction with subsequent coronary intervention resulting in a coronary dissection complicated by an aortic dissection. The coronary dissection was treated with coronary stents. Transesophageal echocardiogram visualized the intracoronary stent within the intimal flap of the aortic dissection. The aortic dissection was successfully managed conservatively.

Aortic Dissection↗

PubMed2006

Pathophysiological basis for monitoring of whole heart conductance by 2-lead system.

BACKGROUND: The defibrillation threshold (DFT) is elevated during myocardial ischemia, but the underlying mechanism remains to be elucidated. The hypothesis tested by the present study was that whole heart conductance (WHC) is a determinant of DFT. METHODS AND RESULTS: WHC was monitored across the longest diameter of the isolated perfused rat heart, using a 2-electrode instrument under various conditions including ischemia-reperfusion (IR). In the control study, WHC was influenced by the conductivity and flow rate of the solution. In IR, WHC decreased immediately after the onset of perfusion arrest in a single exponential manner, then declined again gradually. The second decrease was augmented and accelerated by pretreatment with 1.0 mmol/L heptanol (p<0.005) or high-[Ca2+]e (p<0.001), and was attenuated and delayed by pretreatment with 1.0 micromol/L verapamil (p<0.01). WHC after reperfusion was greater than the pre ischemic level. The postischemic increase in WHC was proportional to the ischemic interval and tissue water content as assessed by desiccation method. CONCLUSION: Although time-dependent alterations in DFT in ischemic hearts may be attributable at least in part to dynamic changes in WHC, WHC should be interpreted carefully because it reflects many physiological factors such as coronary perfusion, electrical coupling of cardiac myocytes and tissue edema.

Animals↗

PubMed2003

Bezold-Jarisch-like reflex during Brockenbrough's procedure for radiofrequency catheter ablation of focal left atrial fibrillation: report of two cases.

Brockenbrough's puncture technique has been widely conducted in the electrophysiologic laboratory. We report here two cases exhibiting a rare complication of this procedure, which arose during the conduct of catheter ablation using radiofrequency energy delivered to the pulmonary vein for the treatment of focal left atrial fibrillation. These cases exhibited marked sinus bradycardia and profound hypotension, suggestive of a Bezold-Jarisch-like reflex, observed immediately after Brockenbrough's procedure but before radiofrequency application. ST elevation in the inferior leads was also observed in spite of normal coronary angiograms. This unanticipated transient complication was treated by intravenous administration of atropine, which had no influence on the ablation procedure or prognosis. This is speculated to be attributable to the elevation of vagal tone caused by the mechanical effects of transseptal puncture on the interatrial vagal network.

Adult↗

PubMed2002

Arrhythmogenic and inotropic effects of interferon investigated in perfused and in vivo rat hearts: influences of cardiac hypertrophy and isoproterenol.

Although the arrhythmogenic effects of interferon (IF) have been reported in clinical practice, the experimental data are limited. Therefore, these effects were investigated in in vivo and Langendorff-perfusion studies using 3 different groups of rats (ie, control, aorta-banded, and deoxycorticosterone acetate (DOCA)-salt hypertension groups) in the presence or absence of isoproterenol. In the perfusion study, human recombinant IF-alpha (< or =15,000 U/ml) alone induced irreversible atrioventricular blockade in all groups, whereas this agent (< or =1,500 U/ml) caused negative inotropism and ventricular tachyarrhythmias (arrhythmic score greater in the order of DOCA-salt>aorta-banded = control group) in the preparations pretreated with isoproterenol (10(-9) mol/L). In an in vivo study, IF-alpha (6x10(6) U/kg) resulted in ventricular tachyarrhythmias only in the presence of isoproterenol (10 mg/kg), as in the perfusion study (arrhythmic score; DOCA-salt>aorta-banded>control). In conclusion, the arrhythmogenesis of IF-alpha is potentiated in pathophysiological conditions such as cardiac hypertrophy or elevated sympathetic activity.

Animals↗

PubMed2002

Sick sinus syndrome disclosed by the successful radiofrequency catheter ablation of persistent common atrial flutter.

Sick sinus syndrome was disclosed in a 77 year-old man after a radiofrequency (RF) linear catheter ablation of cavotricuspid isthmus for persistent common atrial flutter. Prolongation of corrected sinus node recovery time, sinoatrial conduction time and AH interval, as observed after RF ablation, suggested binodal (sinus as well as atrioventricular node) dysfunction. Adams-Stokes syndrome due to sinus arrest was encountered on the day of RF ablation and a permanent DDD pacemaker was implanted consequently. Our experience indicates that careful observation is very important after the RF ablation when atrial flutter is associated with sick sinus syndrome. The present case suggests that binodal dysfunction underlies persistent atrial flutter and vice versa.

Aged↗

PubMedDate not supplied

Cholesterol embolization treated with corticosteroids--two case reports.

Cholesterol embolization (CE) is a potentially serious complication associated with invasive arterial maneuvers, in which standard therapy has not been established. We experienced two cases of CE in patients with severe atherosclerosis whose renal function deteriorated within a few months after invasive arterial maneuvers. CE was confirmed either by renal biopsy (case 1) or skin biopsy (case 2). Oral administration of prednisolone at a daily dose of 30 mg (0.4 mg/kg) was effective to improve their renal function. Our observation suggests that corticosteroid therapy may be beneficial in some patients with CE.

Aged↗