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Biomedical subjects

Takumi Yamada

Publications and source records attributed to Takumi Yamada.

At least 19 recordsLinked to original sources
PubMed2007

A novel catheter for simultaneous angiography of ipsilateral pulmonary veins.

We designed a novel catheter for simultaneous angiography of ipsilateral pulmonary veins (PVs), so that the catheter tip with side holes can be introduced into the inferior PVs and a second curve with side holes into the superior PVs. The simultaneous angiogram of the ipsilateral PVs, using this novel catheter, reveals more clearly the PV ostium to antrum, because simultaneous injection of contrast medium into two adjacent PVs reduces the dilution of contrast medium by blood flow through these veins.

Atrial Fibrillation↗
PubMed2006

Role of volume and attenuation value histogram of urinary stone on noncontrast helical computed tomography as predictor of fragility by extracorporeal shock wave lithotripsy.

OBJECTIVES: To test, for the first time, the predictive capability of the total stone volume (TSV) and the attenuation value histogram. Recently, the mean attenuation value (MAV) of urinary stones has been recognized as a predictor of fragility by extracorporeal shock wave lithotripsy. However, properties other than MAV, including the TSV and the heterogeneity of attenuation value histogram, may also be related to fragility. METHODS: A total of 62 renal and proximal ureteral radiopaque stones treated with extracorporeal shock wave lithotripsy were included in this prospective study. Stones less than 5 mm or greater than 20 mm were excluded. Attenuation value histograms were graphed from the data from noncontrast helical computed tomography scans. The TSV, MAV, and hump existence (HE) on the histogram were also calculated. These parameters were compared between the treatment success and treatment failure groups. RESULTS: Of the 62 stones, 6 were excluded, 39 were in the success group, and 17 in the failure group. Of the 56 stones, 16 had a hump and 40 did not on the attenuation value histograms. The TSV, MAV, and HE were significantly different statistically between the two groups (P <0.001), with an accuracy of 82.1%, 83.9%, and 91.1%, respectively. Also, HE was the only independent predictor of success or failure of extracorporeal shock wave lithotripsy on multivariate analysis (P = 0.0073). CONCLUSIONS: Our results have suggested that TSV, MAV, and HE are good predictors of stone fragility. The treatment modality of the stone should be selected according to the HE, which is a practical, simple, and predictive index.

Humans↗
PubMed2006

Plasma atrial natriuretic Peptide and brain natriuretic Peptide levels after radiofrequency catheter ablation of atrial fibrillation.

It has been reported that plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels are elevated in patients with atrial fibrillation (AF). The aim of this study was to investigate the change in these patients after pulmonary vein isolation (PVI). In 66 patients with paroxysmal AF (PAF) and without any structural heart disease, plasma ANP and BNP levels were measured before and 3 months after successful PVI. At baseline, in 14 patients, ANP and BNP levels were elevated, and in 52 patients, only BNP levels were elevated. There were no significant relations between the attack frequency or the duration of PAF episodes and ANP or BNP levels. Neither ANP nor BNP level at baseline was a valid predictor of AF recurrence. Even in 31 patients (47%) with recurrent PAF, attacks of PAF were significantly reduced. In 66 patients with elevated ANP and/or BNP levels at baseline, levels were significantly reduced after PVI independent of PAF recurrence (ANP: 69.0+/-23.0 vs 25.0+/-7.7 pg/ml, p<0.0001; BNP: 58.4+/-50.7 vs 22.5+/-27.1 pg/ml, p<0.0001). In 42 patients without AF recurrences, ANP and BNP levels were reduced to within the normal range. In conclusion, in patients with PAF without any structural heart disease, ANP and/or BNP levels were elevated. In those patients, relief of the AF burden by successful PVI significantly reduced elevated plasma ANP and BNP levels.

Atrial Fibrillation↗
PubMed2006

Usefulness of esophageal leads for determining the strategy of pulmonary vein ablation to avoid complications associated with the esophagus.

To avoid fatal complications after extensive pulmonary vein (PV) ablation, it has been proved important to comprehend the anatomic relation between the PVs and the esophagus. In 42 consecutive patients with atrial fibrillation, PV ostial isolation was performed using a basket catheter. The shortest distance and anatomic relation between the esophageal lead and PV ostium, determined by successful PV ostial isolation, was analyzed in biplane fluoroscopic views. In 18 left superior PVs (LSPVs) (43%), 13 left inferior PVs (32%) (LIPVs), and all the right PVs (group A), the shortest distance was > 10 mm in > or = 1 of the biplane fluoroscopic views. In 4 LSPVs (10%) and 2 LIPVs (5%) (group B), the shortest distance was < or = 5 mm in the fluoroscopic views. In the remaining PVs (group C), the esophagus was situated directly behind 10 LSPVs (24%) and 12 LIPVs (29%) (group C1), posteromedial to 1 LSPV (2%) and 9 LIPVs (22%) (group C2), and medial to 9 LSPVs (21%) and 5 LIPVs (12%) (group C3). The risk of esophagus-associated complications with ablation around the left PV ostia was suggested to be high in group B, very low in group A, and relatively low in group C. In group C3, extensive PV ablation might increase the risk of that complication. In conclusion, esophageal leads are useful for determining strategies for PV ablation to avoid esophagus-associated complications, because they enable comprehension of the anatomic relation between the PVs and the esophagus.

Atrial Fibrillation↗
PubMed2006

Incidence, location, and cause of recovery of electrical connections between the pulmonary veins and the left atrium after pulmonary vein isolation.

AIMS: The aim of this study was to reveal the incidence, location, and cause of recovery of the electrical connections (ECs) between the left atrium and the pulmonary veins (PVs) after the segmental ostial PV isolation (PVI). METHODS AND RESULTS: Pulmonary vein mapping and successful PVI were performed using a computerized three-dimensional mapping system (QMS2trade mark) with a basket catheter in 167 PVs in 53 consecutive patients with atrial fibrillation (AF). In 14 patients with recurrent AF after PVI, the same PV mapping and isolation as in the first procedure were performed, and the PV potential maps constructed by QMS2 in two different procedures were compared. Forty-nine recovered ECs were observed in 27 PVs, and all were eliminated by a few local radiofrequency (RF) applications. Thirty-four (69%) of those ECs recovered at the edge of original ECs, and another 15 (31%) recovered at the mid-portion of the continuous broad original ECs. CONCLUSION: Electrical connection recovery occurred most commonly at the edges of original ECs and occasionally at the mid-portion of continuous broad original ECs after PVI probably due to tissue oedema neighbouring the segmental RF lesions. Further RF lesions at the edge of original ECs and linear ablation to the continuous broad ECs may help reduce AF recurrence.

Atrial Fibrillation↗
PubMed2006

Bilateral renal angiomyolipoma coexistent with pulmonary lymphangioleiomyomatosis and tuberous sclerosis.

A case of bilateral renal angiomyolipoma coexistent with pulmonary lymphangioleiomyomatosis and tuberous sclerosis was described, being in shock with massive hematuria. The left giant angiomyolipoma, filling the almost entire abdomen, was complicated with two large hump and moniliform aneurysms. This life-threatening hemorrhage was successfully treated by transcatheter arterial embolization; packing mechanically detachable coils into the aneurysms and embolization of trunk of the left renal artery. Lymphangioleiomyomatosis has been suggested to be an incomplete expression of tuberous sclerosis. Although coexisting renal and pulmonary involvement in tuberous sclerosis is rare, it is important to recognize lymphangioleiomyomatosis as a pulmonary involvement of angiomyolipoma with tuberous sclerosis.

Angiomyolipoma↗
PubMed2006

Electrophysiological pulmonary vein antrum isolation with a multielectrode basket catheter is feasible and effective for curing paroxysmal atrial fibrillation: efficacy of minimally extensive pulmonary vein isolation.

BACKGROUND: How extensive should an appropriate pulmonary vein (PV) ablation be is a matter of controversy. OBJECTIVE: The study's aim was to investigate the efficacy of minimally extensive PV ablation for isolating the PV antrum (PVA) with the guidance of electrophysiological parameters. METHODS: Fifty-five consecutive symptomatic paroxysmal atrial fibrillation (PAF) patients underwent PV mapping with a multielectrode basket catheter (MBC). A 31-mm MBC was deployed in 3-4 PVs as proximally as possible without dislodgement, and the longitudinal PV mapping enabled us to recognize single sharp potentials formed by the total fusion of the PV and left atrial potentials around the PV ostium or the transverse activation patterns that were observed. Those potentials were defined as PVA potentials. Radiofrequency ablation was performed circumferentially targeting PVA potentials with the end point being their elimination. RESULTS: After circumferential PVA ablation, electrical disconnection was achieved in 77% and residual PVA conduction gaps were observed in 23% of all targeted PVs. Those residual conduction gaps were mainly located at the border between ipsilateral PVs (42%) and between the left PVs and left atrial appendage (33%) and were eliminated by a mean of 3 +/- 2 minutes of local radiofrequency deliveries. During the follow-up period (11 +/- 5 months), 46 (84%) patients were free of symptomatic PAF without any anti-arrhythmic drugs. No PV stenosis or spontaneous left atrial flutter occurred. CONCLUSIONS: Electrophysiological PVA ablation with an MBC is feasible and effective for curing PAF because this minimally extensive PVA isolation technique targets the optimal sites, achieving both high efficacy and safety.

Aged↗
PubMed2006

HtrA2 is up-regulated in the rat testis after experimental cryptorchidism.

AIM: The aim of the present study was to elucidate the role of high temperature requirement A2 (HtrA2) in germ cell loss in the heat-stressed testis. METHODS: We examined the expression of HtrA2, caspase-9 activity and proteolytic activity of HtrA2 in the rat testis, and their in vivo responses to experimental cryptorchid treatment. RESULTS: Northern analysis revealed the expression of HtrA2 mRNA peaked at days 1 and 7 after cryptorchid treatment. While expression of HtrA2 mRNA was seen in the spermatogonium, spermatocytes and some spermatids in normal adult rat testis, experimental cryptorchidism treatment resulted in a marked increase in its signal intensity in spermatocytes and some spermatids, and the layers of spermatogonium and early primary spermatocytes became negative at days 1 and 7 after the treatment. However, the spermatogonium, Sertoli cells and interstitial cells appeared to have strong intensities at days 14, 28 and 56 after the treatment. Western analysis revealed the expression of HtrA2 protein peaked at day 2 coinciding with the increase of positive spermatogonium, the appearance of protein-positive interstitial cells, and day 28 coinciding with the reappearance of protein-positive interstitial cells. Caspase-9 activity peaked at day 2 and HtrA2 proteolytic activity peaked at day 28. Consequently, the first peak of HtrA2 mRNA expression was followed by the peak of caspase-9 activity and the second peak was followed by the peak of proteolytic activity; however, the second peak of mRNA expression had considerable chronological difference from that of the protein. CONCLUSION: These findings suggest the probabilities that the heat stress results in germ cell death by a caspase-independent manner with the elevation of HtrA2 proteolytic activity, as well as a caspase-dependent manner with the elevation of caspase-9 activity.

Animals↗
PubMed2006

Asthenospermia in hay fever patients improved by stopping treatment with histamine H1 receptor antagonists.

We report two cases of asthenospermia, which appeared to be associated with exposure to histamine H1 receptor antagonists. A 44-year-old man and a 35-year-old man had continued the treatment with fexofenadine hydrochloride and cetirizine hydrochloride, respectively, under the diagnosis of hay fever. They and their wives had been examined as infertile couples. Infertility evaluations revealed no problems with their wives; the patients, however, were found to have a low sperm motility (<10%). On suspicion of adverse effects of the histamine H1 receptor antagonists, they stopped treatment with these drugs, which resulted in a complete reversal of spermatic dysfunction. Current information identifies the potential fertility hazards of histamine H1 receptor antagonists.

Adult↗
PubMed2006

Focal atrial fibrillation associated with multiple breakout sites at the crista terminalis.

A 34-year-old man with permanent atrial fibrillation (AF) underwent electrophysiologic testing. Spontaneous AF was observed even after successful pulmonary vein (PV) isolation of all four PVs. Intracardiac electrograms recorded from a basket catheter deployed around the crista terminalis during triggered atrial premature beats exhibited low-amplitude potentials which were suggested to reflect focal ectopic activity, preceding high-frequency atrial potentials. The firing from those focal activity sites induced a shift in the breakout sites and conduction block to the right atrium, which suggested the participation of preferential conduction. Radiofrequency catheter ablation targeting the focal origin and preferential conduction sites eliminated the AF.

Adult↗
PubMed2006

Does RV lead positioning provide additional benefit to cardiac resynchronization therapy in patients with advanced heart failure?

BACKGROUND AND OBJECTIVES: The left ventricular (LV) stimulation site is currently recommended to position the lead at the lateral wall. However, little is known as to whether right ventricular (RV) lead positioning is also important for cardiac resynchronization therapy. This study compared the acute hemodynamic response to biventricular pacing (BiV) at two different RV stimulation sites: RV high septum (RVHS) and RV apex (RVA). METHODS AND RESULTS: Using micro-manometer-tipped catheter, LV pressure was measured during BiV pacing at RV (RVA or RVHS) and LV free wall in 33 patients. Changes in LV dP/dt(max) and dP/dt(min) from baseline were compared between RVA and RVHS. BiV pacing increased dP/dt(max) by 30.3 +/- 1.2% in RVHS and by 33.3 +/- 1.7% in RVA (P = n.s.), and decreased dP/dt(min) by 11.4 +/- 0.7% in RVHS and by 13.0 +/- 1.0% in RVA (P = n.s.). To explore the optimal combination of RV and LV stimulation sites, we assessed separately the role of RV positioning with LV pacing at anterolateral (AL), lateral (LAT), or posterolateral (PL) segment. When the LV was paced at AL or LAT, the increase in dP/dt(max) with RVHS pacing was smaller than that with RVA pacing (AL: 12.2 +/- 2.2% vs 19.3 +/- 2.1%, P < 0.05; LAT: 22.0 +/- 2.7% vs 28.5 +/- 2.2%, P < 0.05). There was no difference in dP/dt(min) between RVHS- and RVA pacing in individual LV segments. CONCLUSIONS: RVHS stimulation has no overall advantage as an alternative stimulation site for RVA during BiV pacing. RVHS was equivalent with RVA in combination with the PL LV site, while RVA was superior to RVHS in combination with AL or LAT LV site.

Cardiac Pacing, Artificial↗
PubMed2006

Adenosine can also improve the conduction between the superior vena cava and right atrium after isolation.

A 64-year-old man with atrial tachycardia (AT) 3 years after a superior vena cava (SVC) isolation for atrial fibrillation underwent electrophysiologic testing. SVC mapping with a basket catheter revealed a more frequent activation in the SVC than in either of the atria during the AT and consequently the recovered conduction between the SVC and right atrium. The conduction improved from 3 or 4-1 conduction to 2-1 conduction after adenosine was administered. Ectopic firing in the SVC persisted even after restoration of sinus rhythm by the successful SVC isolation, which was confirmed by adenosine.

Adenosine↗
PubMed2006

The distal protection during primary percutaneous coronary intervention alleviates the adverse effects of large thrombus burden on myocardial reperfusion.

BACKGROUND: The presence of intracoronary large thrombus burden (LTB) in the infarct-related artery increases the risk of distal embolization and no-reflow during percutaneous coronary intervention (PCI). Evaluation of whether the distal protection (DP) during primary PCI reduces adverse effects of LTB on myocardial reperfusion and infarct size was investigated. METHODS AND RESULTS: A consecutive series of 88 patients with acute myocardial infarction undergoing primary PCI using DP were compared with 81 consecutive patients treated by primary PCI alone. The DP use showed similar post-procedural myocardial blush grade (MBG)-3 and infarct size, but improved corrected thrombolysis in myocardial infarction frame count (cTFC) (29+/-11 vs 35+/-20, p=0.011) and the incidence of ST-segment resolution (80.7% vs 66.7%, p=0.038). In patients with LTB present, however, the DP use reduced occurrences of no-reflow (0% vs 11.8%, p=0.036) and distal embolization (4.8% vs 17.6%, p=0.129), resulting in higher occurrences of MBG-3 (61.9% vs 35.3%, p=0.021) and ST-segment resolution (78.6% vs 50.0%, p=0.009), lower cTFC values (30+/-8 vs 40+/-22, p=0.012) and smaller infarct size (12.2+/-11.2 vs 18.7+/-11.1, p=0.015). CONCLUSIONS: With an improved myocardial reperfusion and smaller infarct size in patients with LTB, the DP during primary PCI might be a better strategy in this particular setting compared with conventional strategy.

Acute Disease↗
PubMed2006

Can segmental pulmonary vein ablation reduce the recurrence of atrial fibrillation when using a higher RF power, larger tip electrode catheter, and additional RF deliveries?: the limitations of point-by-point RF ablation.

The aim of this study was to investigate whether segmental ostial catheter ablation (SOCA) designed to prevent the electrical connections (ECs) between the left atrium and pulmonary veins (PVs) might help increase the efficacy of SOCA in paroxysmal atrial fibrillation (PAF). PV mapping and successful SOCA were performed with a basket catheter in 108 consecutive patients with PAF. Radiofrequency energy was delivered using a maximum output of 30 W with a 4 mm tip catheter (group I; 47) or 40 W with an 8 mm tip catheter (group II; 61). Only in the group II patients were additional radiofrequency deliveries to the specific sites where the ECs tended to recover performed after successful SOCA. After the first procedure, PAF recurred in 47% of the group I patients and 32% of the group II patients. In all 27 patients who underwent repeat procedures, EC recoveries were observed more frequently in group I than in group II (69% versus 49%; P < 0.05). After multiple procedures, there was more freedom from PAF in group II (84%) than in group I (66%) (P < 0.05). SOCA with a higher RF power, larger tip catheter, and additional RF deliveries could achieve a more effective SOCA.

Aged↗
PubMed2006

[Inflammatory myofibroblastic tumor of the renal pelvis].

Inflammatory myofibroblastic tumor (IMT) of the genitourinary tract is rare and has been classified into separate groups based on their anatomical site and postulated aetiology. Herein, we present a case of IMT of the renal pelvis. A 44-year-old man presented with gross hematuria. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) revealed a tumor of the left renal pelvis. Under the diagnosis of left renal pelvic tumor, he underwent left nephrectomy and ureterectomy. Microscopic examination revealed fascicular spindle cell proliferation in an oedematous myxoid background with an infiltrate of plasma cells. The spindle cells were strongly positive for smooth muscle actin (SMA) and vimentin, and negative for desmin and anaplastic lymphoma kinase (ALK). Diagnosis of the lesion was IMT of the renal pelvis.

Adult↗
PubMed2006

[Primary leiomyosarcoma of the spermatic cord with an unusually indolent clinical course].

A 33-year-old man referred to our hospital with a painful swelling of the left scrotal content which had gradually enlarged during the past 4 years. Physical examination revealed a hard, irregular, nontender mass of 5x4 cm in the left scrotum. The mass was fixed to the left epididymis and spermatic cord. Local excision was performed and histologcal examination revealed leiomyosarcoma originating from the spermatic cord. Distant metastases were not observed. Because of the reportedly high propensity for local recurrence, we performed radical orchiectomy and adjuvant radiation. The patient has been alive for 13 months with no evidence of disease.

Adult↗