Search PubMed⌕ Search

Biomedical subjects

Koichi Taniguchi

Publications and source records attributed to Koichi Taniguchi.

At least 55 records · Page 3Linked to original sources
PubMed2004

Successful catheter ablation of atrial tachycardia originating near the atrioventricular node from the noncoronary sinus of Valsalva.

This report describes a patient who underwent RF catheter ablation of atrial tachycardia. Two applications of RF energy near the His-bundle region transiently terminated the tachycardia. With detailed mapping at the aortic sinus of Valsalva using a retrograde transaortic approach, the earliest atrial activation was found in the noncoronary sinus of Valsalva. Complete elimination of the tachycardia was achieved with RF energy application from this site.

Atrioventricular Node↗
PubMed2004

Evaluation of salvaged myocardium after acute myocardial infarction using single photon emission computed tomography after 201Tl-glucose-insulin infusion.

BACKGROUND: GIK-201Tl imaging reportedly improves the detection of viable myocardium, so the present study evaluated whether it can detect myocardial viability after acute myocardial infarction (AMI). METHODS AND RESULTS: Resting 201Tl and 99mTc-pyrophosphate (PYP) dual single photon emission computed tomography (SPECT) and 201Tl SPECT after 201Tl with GIK (10% glucose, insulin 5 U, and KCl 10 mmol) infusion (GIK-201Tl) were performed in 25 AMI patients within 10 days of admission. GIK-201Tl SPECT images were obtained immediately and 4 h after infusion. Left ventriculography (LVG) was performed within 3 weeks and at 6 months when follow-up 201Tl SPECT was also performed. From 20 SPECT segments, both the summed defect score (RDS) and the number of defect segments (ES) were calculated. The infarcted area was defined as 99mTc-PYP uptake segments. Wall motion was estimated in 7 LVG segments. The ES of R-201Tl (5.5 +/- 2.8), immediate GIK-201Tl (4.0 +/- 2.3), and 4-h GIK-201Tl (5.6 +/- 2.7) were lower than that of 99mTc-PYP (7.5 +/- 4.1) (p<0.05), and the ES had significantly declined 6 months later on 201Tl (3.5 +/- 2.8) (p<0.05). Although the RDS of R-201Tl (11.3 +/- 7.9) and 4-h GIK-201Tl (11.2 +/- 6.3) were greater than at the 6-month 201Tl (7.1 +/- 6.5), immediate GIK-201Tl (7.4 +/- 6.5) was equivalent to follow-up 201Tl. The sensitivity of immediate GIK-201Tl was highest among the imaging methods. CONCLUSION: To detect myocardial viability after AMI, early imaging with GIK-201Tl is more useful than resting 201Tl imaging.

Aged↗
PubMed2004

Effects of antiplatelet agents on subacute thrombosis and restenosis after successful coronary stenting: a randomized comparison of ticlopidine and cilostazol.

BACKGROUND: A prospective randomized study compared the preventive effects of ticlopidine plus aspirin therapy versus cilostazol plus aspirin therapy on subacute thrombosis (SAT) and restenosis after coronary stenting. METHODS AND RESULTS: After successful stenting of 327 coronary lesions in 282 consecutive patients, the patients were randomized to receive ticlopidine (200 mg/day) or cilostazol (200 mg/day). Aspirin (81 mg/day) was administered concomitantly in both groups. SAT occurred in 1 patient in the ticlopidine group (0.7%) and in 8 patients in the cilostazol group (5.6%, p=0.037). Based on follow-up angiography, restenosis occurred in 30 patients (23.3%) in the ticlopidine group and 35 patients (26.9%) in the cilostazol group (NS). The late loss was significantly smaller in the cilostazol group than the ticlopidine group (1.08+/-0.95 mm vs 0.78+/-0.93 mm, respectively, p=0.037). No significant differences between the 2 groups were observed with respect to the rates of total death, non-fatal cardiovascular events, or bleeding complications. CONCLUSION: The ticlopidine group showed significantly less SAT after stenting compared with the cilostazol group. After 6 months of treatment, the inhibition of neointimal proliferation was greater in the cilostazol group than in the ticlopidine group, but the prevention of restenosis was not confirmed.

Aged↗
PubMed2004

Prevalence and electrocardiographic characteristics of idiopathic ventricular arrhythmia originating in the free wall of the right ventricular outflow tract.

BACKGROUND: The prevalence and ECG characteristics of idiopathic ventricular arrhythmia originating in the free wall of the right ventricular outflow tract (RVOT) require further clarification, which was the aim of the present study of 110 patients with idiopathic ventricular tachycardia (n=34) or premature ventricular contraction (n=76; OT-VT/PVC) who underwent successful catheter ablation at the RVOT. METHODS AND RESULTS: Ten OT-VT/PVCs (9%) were ablated successfully at the free wall (FW-VT/PVC); the remaining 100 (91%) were ablated at the RVOT septum (Sep-VT/PVC). R wave amplitudes in the inferior leads were significantly smaller in FW-VT/PVC than in Sep-VT/PVC (p<0.01). An RR' pattern in the inferior leads was observed significantly more often in FW-VT/PVC than in Sep-VT/PVC (p<0.001). QS-wave amplitude in each of leads V(1) to V(3) was significantly deeper in FW-VT/PVC than in Sep-VT/PVC (p<0.001). ECG criteria requiring an RR' pattern in all inferior leads as well as an S-wave amplitude of at least 3.0 mV in lead V(2) differentiated FW-VT/PVC from Sep-VT/PVC with high sensitivity, specificity, and predictive accuracy. CONCLUSIONS: Although FW-VT/PVC has a relatively low prevalence, it has several distinctive ECG characteristics and detailed ECG analysis can differentiate it from Sep-VT/PVC.

Adult↗
PubMed2004

Factors predicting success in cryoablation of the pulmonary veins in patients with chronic atrial fibrillation.

BACKGROUND: This study was designed to investigate the factors predicting maintenance of sinus rhythm (SR) in patients with chronic atrial fibrillation (AF) undergoing cryoablation of the pulmonary veins (PV-cryo) during cardiac surgery. METHODS AND RESULTS: Seventy-seven patients with AF undergoing PV-cryo were recruited and divided into 2 groups based on whether they were able to maintain SR at discharge. The duration of AF (AF-D), left atrial dimension (LAd), and the average of the peak left atrial appendage outflow velocities (LAA-V) before surgery were determined for both groups. Group SR consisted of 54 patients (70%), and group AF consisted of 23 patients (30%). All patients with an AF-D 40 cm/s were in group SR and all those with an AF-D >10 years and LAd >or=65 mm were in group AF. Only 71% of patients with a LAA-V <or=20 cm/s were in group AF. CONCLUSIONS: Restoration of AF to SR by PV-cryo can be predicted from a knowledge of the AF-D, LAd and LAA-V.

Aged↗
PubMed2004

[Does cardiac resynchronization therapy improve nitric oxide concentration in exhaled gas?].

OBJECTIVES: Cardiac resynchronization therapy (CRT) is widely known to improve cardiac function in patients with chronic heart failure, especially those with increased intraventricular conduction delay. However, whether vascular endothelial cell function is improved remains unknown. Capability of nitric oxide (NO) production is a good marker to evaluate endothelial cell function. Therefore, NO output was measured in exhaled air in patients with chronic heart failure after CRT. METHODS: Six patients with chronic heart failure and dilated cardiomyopathy (mean age 62.0 +/- 11.3 years, left ventricular ejection fraction 22.8 +/- 11.6%) received CRT. Pacing leads were lodged at the right atrium, the apex of the right ventricle and at the mid portion of the postero-lateral branch of the coronary sinus. One month after CRT, endtidal NO concentration was evaluated with and without pacing using the chemiluminescence method. RESULTS: Left ventricular ejection fraction improved from 22.8% to 28.8% after the procedure. Endtidal NO was significantly (p = 0.038) increased from 64.7-13.2 ppb without pacing to 69.1-14.1 ppb with pacing. Respiratory rate (with pacing: 19.7-5.7 n/min, without pacing: 20.3-4.8 n/min), tidal volume (with pacing: 523.2-122.7 ml, without pacing: 516.2-160.3 ml) and minute ventilation were not changed. CONCLUSIONS: CRT did not affect respiratory rate, tidal volume or minute ventilation, so increased endtidal NO did not result from enhanced production from tracheal and/or bronchial epithelial cells. Therefore, endtidal NO increased because chronic heart failure increased pulmonary perfusion and so raised vascular shear stress. CRT for patients with dilated cardiomyopathy can improve vascular endothelial cell function.

Aged↗
PubMed2003

Delayed recovery of left ventricular regional work after coronary angioplasty in patients with opposite wall old myocardial infarction.

To evaluate the changes in left ventricular (LV) regional function during acute ischemia in patients with opposite wall old myocardial infarction (OMI), we examined LV regional work during percutaneous transluminal coronary angioplasty (PTCA) of the left anterior descending artery (LAD) in patients with a posterior OMI. Twelve patients with normal LV contraction (group A) and six patients with posterior OMI (group B) who were scheduled to undergo PTCA were enrolled in this study. All patients had single-vessel coronary artery disease and no collateral circulation. Sixty-second inflation was performed, and data were collected every 10 s. The regional work was calculated from the relationship between the mean wall stress and area strain. Regional work of the interventricular septum decreased after balloon inflation and was at its minimum at the end of inflation (group A: 0.6 +/- 0.3 mJ/cm(3); group B: 0.8 +/- 0.4 mJ/cm(3)). After balloon deflation, the septal regional work increased in both groups, and recovered to baseline at 40 s in group A and at 60 s in group B. Regional work of the posterior wall increased in group A after balloon inflation, but not in group B. The recovery of LV regional work after PTCA is delayed in patients with opposite-wall OMI.

Adult↗
PubMed2003

Sulfonated human immunoglobulin enhances CD16-linked CD11b expression on human neutrophils.

Intravenous human immunoglobulin therapy infrequently results in excessive inflammatory responses in vivo; these effects are not fully understood. We assessed whether sulfonated human immunoglobulin (SHIG) or polyethylene glycol-treated human immunoglobulin (PHIG) enhanced expression of inflammatory receptors on peripheral blood neutrophils in vitro, such as alphaMbeta2 (CD11b/CD18) and Fc gamma receptor type III (FcgammaRIII). CD11b and CD16 expression on neutrophils was measured by fluorescence flow cytometry. Various cytokines were assessed using a highly sensitive fluorescence microsphere system. SHIG enhanced/induced CD11b expression and partial aggregations on neutrophils, but PHIG did not. No detection of aggregation IgG was observed in SHIG and PHIG. SHIG-induced CD11b expression was inhibited by treatment of corticosteroid (dexamethasone) and by anti-CD16 monoclonal antibody. Concentrations of various cytokines such as interleukin (IL)-1beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, RANTES, tumor necrosis factor (TNF)-alpha, and interferon (INF)-gamma in culture supernatant were not significantly changed by SHIG or PHIG. SHIG and PHIG did not enhance CD16 on neutrophils. SHIG enhanced CD16-linked CD11b expression on neutrophils in vitro. CD11b induction was inhibited by dexamethasone and by anti-CD16 antibody. These in vitro results suggest that aggregations and enhancement of CD11b on neutrophils by SHIG may induce excessive inflammatory responses in vivo.

Antibodies↗
PubMed2003

Nitric oxide exhalation correlates with ventilatory response to exercise in patients with heart disease.

AIMS: It is controversial whether or not pulmonary nitric oxide (NO) production, reflected in the end-tidal alveolar NO concentration, is diminished in patients with heart failure. Since pulmonary perfusion is regulated by NO production, decreased NO production in the pulmonary vasculature is assumed to result in diminished lung perfusion and further increases in ventilation-perfusion mismatch. The aim of this study is to investigate whether exhaled NO correlates with both exercise-induced hyperpnea and exercise tolerance in patients with heart disease. METHODS AND RESULTS: Forty-two patients with heart disease were enrolled (history of prior myocardial infarction (n=19), dilated cardiomyopathy (n=2), hypertensive heart disease (n=5) and prior open-heart surgery (n=16)). During cardiopulmonary exercise testing, exhaled air was collected and end-tidal NO (ETNO) was measured using a chemiluminescent method. Peak ETNO was found to correlate positively with both ventilatory anaerobic threshold (r=0.468) and peak VO(2) (r=0.562). The VE-CO(2) slope, which reflects the ventilatory response to exercise, correlated negatively with peak ETNO (r=-0.588). CONCLUSION: These data indicate that NO exhalation correlates, inversely, with the ventilatory response to exercise and directly with exercise intolerance, although the weakness of the correlation coefficient suggests there may be other possible mechanisms.

Exercise↗
PubMed2003

Concealed left anterior accessory pathways: two approaches for successful ablation.

Left anterior accessory pathways are considered to occur rarely because the junction between the aortic and mitral valve areas represents a fibrous continuity. Of 207 patients with concealed left accessory pathways in whom catheter ablation was performed at our institution over the past 8 years, two patients had concealed left anterior accessory pathways. The polarity of the retrograde P waves was positive in the inferior leads and negative in leads I and aVL during orthodromic reciprocating tachycardia. Complete elimination of accessory pathway conduction was achieved using a transseptal approach or with radiofrequency energy application from the left sinus of Valsalva.

Adolescent↗
PubMed2003

Successful catheter ablation of an anteroseptal accessory pathway from the noncoronary sinus of Valsalva.

We describe a patient who underwent radiofrequency catheter ablation of concealed left lateral and anteroseptal accessory pathways. After successful elimination of the concealed left anterolateral accessory pathway, the earliest retrograde atrial activation was located in the His-bundle region. Complete elimination of the accessory pathway conduction was achieved with a radiofrequency energy application from the noncoronary sinus of Valsalva.

Bundle of His↗
PubMed2003

Development and validation of an ECG algorithm for identifying the optimal ablation site for idiopathic ventricular outflow tract tachycardia.

INTRODUCTION: Idiopathic ventricular outflow tract tachycardia or premature ventricular contractions (OT-VTs) can originate from several different sites in the outflow tract, including the left ventricular (LV) endocardium and epicardium. The aims of this study were (1) to develop an ECG algorithm to predict the origin of OT-VT and (2) to test prospectively the accuracy of the algorithm. METHODS AND RESULTS: An algorithm was developed by correlating the 12-lead ECG findings with the catheter ablation site in 80 patients with OT-VT. The ECG characteristics of the QRS complex during the arrhythmia were analyzed. The catheter sites were verified by multi-plane fluoroscopy. The outflow tract was classified into six subdivisions: right ventricular (RV) septum, RV free wall, RV near the His-bundle region, LV endocardium, left sinus of Valsalva (LSV), and LV epicardium remote from the LSV. An OT-VT originating from the LV epicardium remote from the LSV was defined as an OT-VT in which the earliest ventricular activation was recorded at the LSV and radiofrequency ablation from the LSV failed. This algorithm subsequently was tested prospectively in 88 patients. Overall sensitivity was 88% and specificity was 95%. The positive and negative predictive values were 88% and 96%, respectively. CONCLUSION: We describe a new ECG algorithm having a high sensitivity and specificity to identify the optimal ablation site for idiopathic ventricular outflow tachycardia or premature ventricular contractions.

Adolescent↗
PubMed2003

Failure to raise blood pressure during exercise is a poor prognostic sign in patients with hypertrophic non-obstructive cardiomyopathy.

Sudden cardiac death is a well-documented complication of hypertrophic cardiomyopathy and additionally, failure to raise blood pressure (BP) during exercise has been associated with a poor outcome. The present study group comprised 58 patients with hypertrophic non-obstructive cardiomyopathy (HNCM) who were receiving beta-blocker therapy. All patients underwent submaximal exercise radionuclide ventriculography (RNVG) to evaluate left ventricular (LV) function at both rest and peak exercise. Patients were divided into 2 groups based on the increase in systolic BP during exercise (ie, group A <30% or group N >/=30% of resting systolic BP) and were involved in long-term follow-up (10.4+/-4.0 years). Group A comprised 29% of the subjects. Age and workload at peak exercise were similar in the 2 groups. LV end-diastolic dimension was smaller and the interventricular septum was thicker in group A. LV ejection fraction on RNVG was similar in the 2 groups at rest and at peak exercise. During the follow-up period, more patients in group A than group N suffered syncopal attack (29% vs 5%, p<0.05) and cardiac sudden death (24% vs 2%, p<0.05). Patients with HNCM whose BP fails to rise during exercise have a poor prognosis.

Adrenergic beta-Antagonists↗
PubMed2003

Segmental pulmonary vein isolation for paroxysmal atrial fibrillation improves quality of life and clinical outcomes.

The purpose of this study was to clarify the change in the quality of life (QOL) and clinical outcomes following segmental pulmonary vein (PV) isolation for paroxysmal atrial fibrillation (AF) in 50 patients with drug-refractory, paroxysmal AF. The left superior, left inferior, and right superior PVs were targeted for isolation in all patients, and the right inferior PV was isolated in 4 patients. AF recurred in 22 of 50 patients, and these patients were treated with class I or class III antiarrhythmic drugs that had been ineffective before the ablation procedure. The symptom severity and frequency was scored and the QOL was assessed using the Short-Form-36 questionnaire (SF-36) before the PV isolation and at the end of the follow-up period (6.0+/-3.0 months). PV isolation resulted in a reduction in the symptom severity (p<0.001) and symptom frequency (p<0.001) scores as compared with the pre-ablation values. Ninety percent of the patients had a >90% reduction in the frequency of symptomatic episodes of AF after the ablation procedure. The mean SF-36 physical and mental component summary scores also significantly improved after PV isolation as compared with the pre-ablation values (both for p<0.001). With a segmental isolation approach that targets at least 3 PVs, satisfactory improvement in the symptoms and QOL can be achieved in patients with drug-refractory, paroxysmal AF.

Aged↗
PubMed2003

Effectiveness of thrombectomy before stent implantation in acute myocardial infarction.

Percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) may cause distal embolization, with deterioration of distal flow and further extension of the infarct. The purpose of the present study was to evaluate the effectiveness of pretreatment by thrombectomy on myocardial salvage after stent implantation in patients with AMI. From January 2000 to July 2002, 209 consecutive patients with AMI successfully underwent emergency stent implantation. They were divided into 2 groups: those treated in the year before the introduction of the thrombectomy device (Group A; n=109), and those treated the year after introduction of the device (Group B; n=100). Follow-up quantitative coronary angiography (QCA) and left ventriculography were carried out 6 months after PCI. Microvascular circulation after revascularization was assessed by Thrombolysis in myocardial infarction (TIMI) flow grade analysis, the maximum creatine kinase concentration was recorded, and the follow-up left ventricular ejection fraction and ST segment score were assessed on the 12-lead electrocardiography just before revascularization and on return to the coronary care unit. The QCA data, rate of restenosis (% restenosis) and rate of target lesion revascularization were also compared between the 2 groups. The results demonstrated that the introduction of thrombectomy had increased the number of patients who displayed blush-3 after primary angioplasty, which suggests that thrombectomy before stent implantation has the potential to minimize myocardial ischemic insult, presumably by protecting the coronary microvasculature.

Aged↗
PubMed2003

Impedance cardiography and quantitative tissue Doppler echocardiography for evaluating the effect of cardiac resynchronization therapy: a case report.

An 83-year-old woman presented with dilated cardiomyopathy. Cardiac resynchronization therapy was performed. Two weeks later, cardiac output and ventricular wall motion were estimated using impedance cardiography and tissue Doppler echocardiography with and without pacing. Cardiac output increased from 3.5 to 4.5 l/min during biventricular pacing with a 120 msec atrioventricular interval. Intraventricular phase difference for contraction decreased from 190 to 150 msec. When the atrioventricular interval was 180 msec, cardiac output and phase difference became 4.6 l/min and 170 msec. These assessments were performed rapidly and non-invasively. New impedance cardiography and tissue Doppler echocardiography are useful to evaluate the effect of cardiac resynchronization therapy.

Aged↗