Biomedical subjects

Yukihiko Yoshida

Publications and source records attributed to Yukihiko Yoshida.

15 recordsLinked to original sources

PubMed2006

Role of myocardial interstitial edema in conduction disturbances in acute myocarditis.

The presence of myocardial interstitial edema in acute myocarditis (AM) leads to thickening of the ventricular wall, and conduction disturbances, such as complete atrioventricular block (CAV), also frequently develop. This study was undertaken in order to clarify the relationship between conduction disturbances and myocardial interstitial edema in AM. The subjects comprised 50 patients with acute lymphocytic myocarditis. Based on the results of echocardiographic examinations during the acute stage, the patients were divided into a hypertrophy group (n = 29) in which the sum of the thickness of the interventricular septum and left ventricular (LV) posterior wall was >or=24 mm, and a non-hypertrophy group (n = 21) in which the sum of these parameters was <24 mm. Right ventricular endomyocardial biopsies were performed in the acute stage and the degree of interstitial edema was scored histologically. Left ventricular wall thickness and QRS duration in the acute stage were 27.7 +/- 3.6 mm and 124.1 +/- 29.6 ms, respectively, in the hypertrophy group, and 19.9 +/- 2.4 mm (P < 0.001) and 98.6 +/- 21.7 ms (P < 0.01) in the non-hypertrophy group. Complete atrioventricular block was found in 13 of 29 cases (45%) in the hypertrophy group and two of 21 cases (10%) in the non-hypertrophy group (P < 0.01). Myocardial interstitial edema was scored at 1.3 +/- 0.8 points in the hypertrophy group and 0.8 +/- 0.6 points in the non-hypertrophy group (P < 0.05). Left ventricular wall thickness and QRS duration in the convalescent stage decreased to 21.1 +/- 2.6 mm (P < 0.0001) and 97.1 +/- 17.4 ms (P < 0.01) in the hypertrophy group, respectively. Only one case (4%) in the hypertrophy group continued to show CAV during the convalescent stage (P < 0.05). The results of this study suggest that myocardial interstitial edema is implicated in the conduction disturbances that occur in AM.

Acute Disease↗

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

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

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

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↗

PubMed2005

Computerized three-dimensional potential mapping with a multielectrode basket catheter can be useful for pulmonary vein electrical disconnection.

INTRODUCTION: Pulmonary vein (PV) isolation (PVI) has been recently proposed as an effective technique to cure atrial fibrillation (AF). AIMS OF THE STUDY: The aim of this study was to investigate the efficacy of a novel technique utilizing a computerized three-dimensional mapping system (QMS2) with a multielectrode basket catheter (MBC) for PVI and to reveal the relation between the style of breakthrough and the network of the PV musculature. METHODS: Sixty-five consecutive patients with frequent AF attacks underwent PV mapping with a 31-mm MBC, and a three-dimensional color animation of the potential map was constructed by the QMS2. The animation color schema was arranged to minimize the low-amplitude left atrial (LA) potentials and emphasize the high-amplitude PV potentials (PVPs). The longitudinal PVP map enabled us to recognize the true breakthroughs and reveal the network of the PV musculature. RESULTS: A total of 205 PVs (65 left superior PVs, 65 right superior PVs, 57 left inferior PVs and 18 right inferior PVs) were mapped and successful PVI was achieved in all PVs, except one that had no PVPs, with a mean radiofrequency duration of 7 +/- 5 minutes per PV. In about 90% of the PVs, a final radiofrequency application eliminated all the distal PVPs simultaneously because the PVI was performed at the appropriate LA-PV junction. A single segmental breakthrough was detected in 17 PVs, single broad breakthrough in 83 PVs, multiple separate breakthroughs with a distal connection between the PV musculatures extending from each separate breakthrough in 88 PVs and multiple separate breakthroughs without that connection in 16 PVs. During the follow-up period, fifty-one (78%) patients were free of symptomatic AF without any antiarrhythmic drugs after multiple procedures (thirty-three (51%) of those patients after the first procedure) and no PV stenosis was found. CONCLUSIONS: Computerized three-dimensional potential mapping can be useful for PVI because it can not only identify the true breakthrough, but can also confirm the elimination of the breakthroughs by the change in the activation sequence through the network of the PV musculature.

Analysis of Variance↗

PubMed2004

Diagnostic usefulness of postexercise systolic blood pressure response for detection of coronary artery disease in patients with echocardiographic left ventricular hypertrophy.

BACKGROUND: Although exercise-induced electrocardiographic ST segment changes are used to detect coronary artery disease (CAD), their diagnostic value is markedly decreased in patients with left ventricular (LV) hypertrophy. There have been no reports concerning postexercise systolic blood pressure (SBP) response in patients with ultrasound echocardiographic (UCG) LV hypertrophy and CAD. METHODS: Sixty-six patients with both UCG-LV hypertrophy (LV mass index 134 g/m2 or greater for men or 110 g/m2 or greater for women) and positive ST depression of at least 0.1 mV during treadmill exercise testing were studied. Coronary cineangiograms showed normal coronary arteries in 19 patients (group 1) and significant CAD in 47 patients (group 2). The SBP ratio was calculated by dividing the SBP 3 min after exercise (3 min SBP) by the SBP at peak exercise (peak SBP). RESULTS: There were no significant differences between the two groups in LV mass index, SBP at rest, exercise duration, ST depression (at rest and exercise-induced) or 3 min SBP. However, the SBP ratio was significantly higher in group 2 compared with group 1 (0.87+/-0.11 versus 1.01+/-0.18; P=0.004). Analysis of relative cumulative frequency distributions revealed an SBP ratio of 0.92 as the cutoff point for distinguishing a UCG-LV hypertrophy patient with CAD from one without CAD. The sensitivity, specificity and accuracy with an SBP ratio of 0.92 and an ST segment depression of at least 0.1 mV on treadmill exercise testing for detecting CAD in patients with UCG-LV hypertrophy were 77%, 74% and 76%, respectively. CONCLUSION: These findings suggest that the ratio of early post-exercise SBP to peak exercise SBP may be diagnostically useful in detecting CAD in patients with positive ST depression during an exercise test and UCG-LV hypertrophy.

Adult↗

PubMed2004

Simple and accurate catheter mapping technique to predict atrial fibrillation foci in the pulmonary veins or posterior right atrium.

OBJECTIVES: The purpose of this study was to investigate the efficacy of a novel catheter mapping technique for predicting atrial fibrillation (AF) foci. BACKGROUND: Most AF originates from pulmonary veins (PVs), but some originate from the right atrium. METHODS: We developed an algorithm by correlating the cardiac recordings obtained from multielectrode catheters placed in the posterior right atrium (RA) and esophagus during pacing from the PVs and superior vena cava (SVC) or crista terminalis (CT) in 10 AF patients. We tested the algorithm's accuracy prospectively in 46 AF patients. RESULTS: During pacing from the left PVs, the esophageal potentials preceded all other potentials. During pacing from both the right PVs and SVC-CT, the first component (FP) of the double potential (DP) recorded in the posterior RA preceded all other potentials. The amplitude of the FP was higher than that of the second DP component during pacing from the SVC-CT, whereas the reverse occurred from the right PVs. The activation sequence of the FPs and esophageal potentials was from superior to inferior during pacing from the superior PVs, whereas the reverse occurred from the inferior PVs. The accuracy of predicting 34 foci in the right PVs, 28 foci in left PVs, and 6 foci in SVC-CT was 100% for all, respectively. The accuracy of discriminating foci in the superior PVs from those in the inferior PVs was 97% in the right PVs and 96% in the left PVs. CONCLUSIONS: The technique using mapping catheters placed in the posterior RA and esophagus is feasible and effective for mapping and ablating AF.

Algorithms↗

PubMed2004

Electrophysiologic characteristics of atrial tachycardia originating from the right pulmonary veins or posterior right atrium: double potentials obtained from the posterior wall of the right atrium can be useful to predict foci of atrial tachycardia in right pulmonary veins or posterior right atrium.

INTRODUCTION: The right pulmonary veins (RPVs) and posterior wall of the right atrium (PRA) are anatomically located adjacent to each other. The aim of this study was to demonstrate the electrophysiologic characteristics of atrial tachycardia (AT) originating from the PRA or RPVs. METHODS AND RESULTS: A total of 26 consecutive patients with AT originating from the RPVs or PRA underwent detailed atrial endocardial mapping and successful radiofrequency catheter ablation. Eight foci were found in the PRA and 18 foci in the RPVs. Analysis of P wave configuration showed that lead V1 was the most helpful in distinguishing the AT foci between these two sites. In all cases, double potential (DP) configurations were recorded from several electrodes of a multielectrode catheter placed in the PRA, and the first DP component (FP) was the earliest potential recorded from the right atrium during the tachycardia. The amplitude of the FP was higher than that of the second DP component (SP) for AT foci originating in the PRA, whereas the reverse occurred for those in the RPV. The activation sequence of the FP was from superior to inferior for the AT foci in the superior RPV, whereas the reverse occurred for the AT foci in the inferior RPV. CONCLUSION: P wave configuration in lead V1 is helpful in distinguishing AT foci between those originating in the PRA and RPVs. The DPs obtained from the PRA can be useful in predicting whether AT foci originate from the PRA or RPVs.

Adolescent↗

PubMed2004

Risk factors for patients developing a fulminant course with acute myocarditis.

BACKGROUND: A fulminant course can be difficult to predict at the onset of acute myocarditis, so the aim of the present study was to identify the predictive clinical symptoms/signs or laboratory findings. METHODS AND RESULTS: Thirty-nine patients with acute lymphocytic myocarditis, excluding 8 who manifested shock at admission, were studied. The fulminant group was defined as 12 patients who developed shock after admission, requiring intraaortic balloon pumping or percutaneous cardiopulmonary support, and the non-fulminant group comprised the 27 patients without shock. Various parameters at admission were compared between the 2 groups, together with multiple logistic regression analysis, excluding 6 patients with partially missing values. In the fulminant group, C-reactive protein (7.0 +/- 7.0 vs 2.3 +/- 2.2 mg/dl, p<0.01) and creatine kinase (1,147 +/- 876 vs 594 +/- 568 IU/L, p<0.05) concentrations were higher, intraventricular conduction disturbances were more frequent (9/12 vs 7/27 patients, p<0.01) and the left ventricular ejection fraction was lower (40.7 +/- 13.9 vs 50.1 +/- 10.6%, p<0.05) than in the non-fulminant group. In the multiple logistic regression analysis model with the presence/absence of a fulminant course considered as the independent variable, and C-reactive protein, creatine kinase, intraventricular conduction disturbances, and left ventricular ejection fraction as dependent variables, a high-risk group (expected proportion of fulminant course > or = 0.5) and a low-risk group (<0.5) could be differentiated. A fulminant course occurred in 9/13 (69%) patients in the high-risk group, but in only 2/20 (10%) patients in the low risk group (p<0.001). CONCLUSIONS: The risk of a fulminant course of acute myocarditis was high in patients with elevated C-reactive protein, and creatine kinase concentrations, decreased left ventricular ejection fraction, and intraventricular conduction disturbances at the time of admission.

Acute Disease↗

PubMed2003

Changes in the peripheral eosinophil count in patients with acute eosinophilic myocarditis.

In many cases, the diagnosis of eosinophilic myocarditis is suggested by an elevated peripheral blood eosinophil count. However, no detailed studies have been performed on the sequential changes in the initial peripheral blood eosinophil count over the course of the disease. We measured the peripheral blood eosinophil count at the time of presentation in eight patients with eosinophilic myocarditis proven by endomyocardial biopsy and intermittently thereafter. The eosinophil count at the time of onset was <500/mm(3) in four patients, >500/mm(3) but <1,000/mm(3) in three patients, and > or =1,000/mm(3) in one patient. In three of the four patients with an initial eosinophil count of <500/mm(3), an increase to > or =500/mm(3) occurred 7-12 days after the onset. The remaining patient did not develop peripheral eosinophilia. In conclusion, in the early stage of eosinophilic myocarditis, peripheral hypereosinophilia is not present initially in some patients, and may not develop during the course of the illness in a subset of these patients.

Acute Disease↗

PubMed2002

Changes in repolarization properties with long-term cardiac memory modify dispersion of repolarization in patients with Wolff-Parkinson-White syndrome.

INTRODUCTION: Transient T wave changes after cessation of preexcitation have been attributed to cardiac memory. However, there have been no reports on the effects of long-term cardiac memory on repolarization dispersion before and after catheter ablation in patients with Wolff-Parkinson-White (WPW) syndrome. METHODS AND RESULTS: We investigated 47 patients with an accessory pathway (AP; 24 manifest left-sided, 14 manifest right-sided, and 9 concealed left-sided). Repolarization dispersion was analyzed by two methods, recovery time (RT) dispersion and newly proposed T wave width (WT), from 87-lead body surface maps before, 1 day after, and 7 days after catheter ablation. RT dispersion and WT were significantly correlated before, 1 day after, and 7 days after catheter ablation (r = 0.78). In patients with preexcitation, RT dispersion and WT increased significantly (P < 0.05) 1 day after catheter ablation (178 +/- 32 msec and 172 +/- 30 msec) compared with those before (154 +/- 24 msec and 156 +/- 18 msec) and 7 days after catheter ablation (147 +/- 19 msec and 156 +/- 16 msec), respectively. However, there were no significant changes in RT dispersion and WT before and after catheter ablation in concealed WPW syndrome. CONCLUSION: The findings suggest that the abrupt changes in activation sequence increase repolarization dispersion in the presence of previous cardiac memory, and that the dispersion decreases days or weeks after alteration of activation sequence by catheter ablation, with development of new cardiac memory in patients with manifest WPW syndrome.

Adaptation, Physiological↗

PubMed2002

[Intravenous vegetation of methicillin-resistant Staphylococcus aureus induced by central venous catheter in a patient with implantable cardioverter-defibrillator: a case report].

A 54-year-old woman with an implantable cardioverter-defibrillator was admitted because of convulsion. Previously, she had suffered methicillin-resistant Staphylococcus aureus (MRSA) sepsis induced by a central venous catheter. Despite removal of the central venous catheter and administration of vancomycin, fever and increased C-reactive protein level persisted. MRSA had probably infected the implantable cardioverter-defibrillator system. Gallium scintigraphy showed accumulation at the right subclaviculan area, although local inflammatory signs were absent. Intravascular ultrasonography demonstrated intravenous vegetation at the bifurcation of the right subclavian vein and right internal jugular vein. Antibiotic therapy was not curative, so she underwent extirpation of the intravenous vegetation, which cured the systemic inflammation. Intravascular ultrasonography was useful to differentiate central venous catheter-related infection from implantable cardioverter defibrillator-related infection.

Catheterization, Central Venous↗