Biomedical subjects

Marehiko Ueda

Publications and source records attributed to Marehiko Ueda.

13 recordsLinked to original sources

PubMed2007

Appearance of noncompaction-like remodeling of the anatomical right ventricle in a middle-aged subject with modified transposition of the great arteries who did not undergo surgery.

We describe noncompaction-like remodeling of the anatomical right ventricle (ARV) in a middle-aged subject with modified transposition of the great arteries (TGA). A 54 year-old male had been diagnosed with modified TGA at age 40, but no surgery was performed. Enhanced multislice CT revealed the ascending aorta coursing left of the anterior pulmonary trunk. Furthermore, the myocardium of the ARV appeared thickened, but contrast material could be observed in the ARV myocardium, which resembled noncompaction of the left ventricle (LV). We speculated trabecular development of the ARV, such as a Chiari network, and with TGA, the ARV provided systemic circulation through the aorta. The ARV wall may have thickened due to systemic pressure load, resulting in reduction of wall motion of the ARV on transthoracic echocardiogram. Recent advances in multislice CT imaging have revolutionized the exploration of RV anatomy, especially for depicting the three-dimensional appearance of noncompaction-like remodeling of the ARV in modified TGA in addition to transposition of the great arteries.

Humans↗

PubMed2006

Occurrence of de novo sustained monomorphic ventricular tachycardia induced after percutaneous transluminal alcohol septal myocardial ablation for hypertrophic obstructive cardiomyopathy.

We report here a 75-year-old male with hypertrophic obstructive cardiomyopathy of de novo sustained monomorphic ventricular tachycardia (VT) after successful percutaneous transluminal alcohol septal myocardial ablation (PTSMA). In this case history, the necrotic induced by the PTSMA procedure might represent a region of slow conduction that is a circuit of re-entry and therefore stimulation might be spread around. Therefore, the basis of the sustained monomorphic VT was thought to be the presence of a focal necrotic area, itself a complication arising from the PTSMA procedures. In conclusion, the PTSMA procedure may have caused a de novo episode of ventricular arrhythmia.

Aged↗

PubMed2006

Remarkable thickening of right atrial wall in subjects with cardiac amyloidosis complicated with sick sinus syndrome.

We observed a 63-year old male with cardiac amyloidosis who presented with the clinical symptoms of sick sinus syndrome and dyspnea and abnormal thickening of the right atrial wall, which extended to the junction of the superior vena cava. This may explain the relationship of abnormal thickening of the right atrium which extends to the junction of the superior vena cava and right atrium with amyloid deposits in the sinus node and occurrence of sick sinus syndrome.

Amyloidosis↗

PubMed2006

Anatomical remodeling of left atria in subjects with chronic and paroxysmal atrial fibrillation evaluated by multislice computed tomography.

PURPOSE: We used ECG-gated enhance multislice computed tomography (MSCT) to evaluate and compare anatomical change to left atria (LA) including left atrial appendage (LAA) in subjects with chronic and paroxysmal atrial fibrillation (CAF and PAF, respectively). MATERIALS AND METHODS: Retrospective ECG-gated MSCT (Light Speed Ultra 16, General Electric) was performed in 16 subjects with CAF (10 male, median age 68/period of CAF 6 years, 3 severe or moderate mitral stenosis (MS), 3 mitral regurgitation (MR)) and 17 with PAF (11 male, median age 62/period of PAF 3 years, one MS, one MR) 30 s and 8 min after injection of contrast. We evaluated: qualified observed morphology of pectinate muscles (PM) in LAA (well/poorly/non-developed); absolute thickness of LA anterior wall; presence of abnormal late enhancement (LE) of LA wall suggesting fibrotic changes; defect of contrast in LAA only in early phase and LAA enlargement; comparison of LA diameter evaluated by 4-chamber view obtained by transthoracic echocardiogram. RESULTS: CAF group: well-developed PM (19% subjects), poor PM (43%), no PM (38%). PAF group: well-developed PM (41%), poor PM (47%), no PM (12%). Incidences of well- and non-developed PM were significantly less and more in CAF group, respectively. CAF subjects with no PM had longer periods of CAF and larger LA diameter than those with developed PM (p<0.01). By contrast, there was no relation between PM morphology and PAF periods or LA diameter. Incidence and mean thickness of abnormal LE of LA wall were similar in both groups (2.6 mm): 25% (CAF); 24% (PAF). There was a negative correlation in the CAF group between thickness of LA wall and LA diameter (R2=0.19), but not in the PAF group. Contrast defect in LAA only in early phase and enlargement of LAA were observed in 56%, 88% (CAF) and 24%, 41% (PAF); ratios were significantly higher in CAF group (p<0.01). CONCLUSIONS: There were anatomical differences between CAF and PAF groups in MSCT. In CAF group, depending on the period of CAF or degree of LA diameter enlargement, anatomical remodeling (e.g. recession of PM, thinning of LA wall, enlargement of LAA) may appear, which may cause blood flow stagnation, seen as contrast defect in LAA in early phase.

Acute Disease↗

PubMed2006

Epidemiology of fat replacement of the right ventricular myocardium determined by multislice computed tomography using a logistic regression model.

PURPOSE: We frequently observe fat replacement (FR) of the anterior wall of the right ventricular myocardium (RVM), but its epidemiological significance is not clear. METHODS AND MATERIALS: 49 consecutive subjects (28 males, 36-83 years old, median 67) underwent enhanced ECG-gated multislice CT (Light speed ultra 16, General Electrics, WI) and we retrospectively analyzed the presence of FR of RVM. A logistic model for predicting FR of RVM was constructed using age, sex, hypertension [HT], diabetes mellitus [DM], hyperlipidemia [HL] smoking, obesity (body mass index >25.0) and calcified and non-calcified plaques of coronary arteries (CA). RESULTS: FR of RVM was detected in 21 subjects (12 males, 51-78 years old, median 67), 76% of whom had HT, 38% DM, 43% HL, 48% smoking history, 52% were obese, and 76% had calcified and 24% had non-calcified plaques of CA. Only obesity was significantly higher in FR (p<0.05). A logistic regression model showed, although there was a close association between obesity and an increased incidence of FR, it did not reach statistical significance (p=0.0515, relative risk 5.11). CONCLUSIONS: Obesity is significantly more common in cases of FR, and despite a negative multivariable analysis, may influence FR in the RVM. FR in obesity may occur independently of clinically-significant arrhythmia, which is different from ARVC. Thus, even with FR, obesity must be considered as a diagnosis before ARVC.

Adult↗

PubMed2005

Simultaneous mapping in the left sinus of valsalva and coronary venous system predicts successful catheter ablation from the left sinus of valsalva.

Idiopathic ventricular tachycardia originating from the left epicardium (Epi-VT) can be ablated from the left sinus of Valsalva (LSV) in selected patients. We hypothesized that the analysis of electrograms at the LSV and transitional zone from the great cardiac vein to the anterior interventricular vein (GCV-AIV) could predict the efficacy of radiofrequency catheter ablation (RFCA) from the LSV. Simultaneous mapping in the LSV and coronary venous system was performed in 25 patients (12 VTs and 13 premature ventricular contractions). The earliest ventricular activation (VA) during the arrhythmias was found at the LSV or GCV-AIV in all patients. RF applications from the LSV were successful in 17 patients success group (S-Gr) and failed in 8 failure group (F-Gr). The earliness of the VA recorded in the LSV (VA[LSV]) and in GCV-AIV (VA[GCV-AIV]) was compared between the two groups. (1) The VA[LSV] preceded the QRS onset by 28 +/- 11 ms in S-Gr and 14 +/- 10 ms in F-Gr (P < 0.01). (2) In S-Gr, the VA[GCV-AIV] was earlier than the VA[LSV] in 5 five patients (35%). However, in F-Gr, the VA[GCV-AIV] was earlier than the VA[LSV] in all patients. (3) In patients in whom the earliest VA was found at the LSV or GCV-AIV, a VA [GCV-AIV] preceding the VA[LSV] by less than 10 ms identified successful RFCA from the LSV with a sensitivity of 88 %, specificity of 100%, and high predictive value. With a detailed analysis of the electrograms recorded from the GCV-AIV and LSV, it was possible to identify the successful catheter ablation of Epi-VT from the LSV.

Catheter Ablation↗

PubMed2005

Pulmonary vein morphology before and after segmental isolation in patients with atrial fibrillation.

BACKGROUND: The morphology of the pulmonary veins (PVs) before and after segmental isolation of the PVs has not been sufficiently characterized. METHODS AND RESULTS: Multi-slice computed tomography was performed before and 3 +/- 1 months after ablation in 30 patients with atrial fibrillation who underwent PV isolation. Before ablation, PV narrowing (> or =25% luminal reduction) was found in nine (8%) PVs. After ablation, de novo PV narrowing was found in 24 PVs (26%) and was detected only in the supero-inferior direction in 14 PVs (58%). The diameter reduction inside the PVs after ablation was greater in the supero-inferior direction (14 +/- 12%) than in the antero-posterior direction (9 +/- 13%; P < 0.0001). In the ablated PVs, the PV trunk was shorter than before ablation (P < 0.0001). The reduction in the diameters of both the PV ostium and the ablation site in the ablated PVs, as well as the diameter of the PV ostium in the nonablated PVs, correlated with the decrease in the left atrial diameter. Shortening of the PV trunk correlated with the severity of PV narrowing, but it was not related to the percent diameter reduction of the left atrium. PV narrowing before or after ablation did not result in any clinical consequences. CONCLUSIONS: PV narrowing is present in about 10% of PVs before ablation. Asymmetric luminal reduction and longitudinal shrinkage of the PV trunk occur after ablation. Reverse remodeling of the PV and contraction of the PV wall may contribute to the reduction in the PV diameter. PV morphology should be assessed with multi-directional views to avoid missing heterogeneous legions.

Analysis of Variance↗

PubMed2005

Three-dimensional visualization of the coronary venous system using multidetector row computed tomography.

BACKGROUND: This study was undertaken to investigate the applicability and image quality of contrast-enhanced visualization of the coronary venous system (CVS) by multidetector row computed tomography (MDCT). METHODS AND RESULTS: A total of 70 patients underwent MDCT and for each patient, 6 data sets were created throughout the cardiac cycle. The number and location of coronary veins were evaluated in 3-dimensional images using the 6 data sets. The quality of all images reconstructed from the 6 data sets was too poor to evaluate the CVS in 6 patients (9%). In the remaining 64 patients (91%), the diameter of the CVS was usually greater in the images reconstructed from data acquired during systole than in those reconstructed from data acquired during diastole. However, artifacts were observed more often in images from systole than from diastole. The coronary sinus and middle cardiac vein were visible in all 64 patients. The left marginal and posterior veins also were identified in 54 (84%) and 60 patients (94%), respectively. CONCLUSIONS: MDCT can be used as a non-invasive modality for evaluating the CVS anatomy in most patients.

Adult↗

PubMed2004

Significance of two potentials for predicting successful catheter ablation from the left sinus of Valsalva for left ventricular epicardial tachycardia.

The aim of this study was to identify the characteristics of electrograms that may be helpful in predicting successful ablation of idiopathic ventricular tachycardia from the aortic sinus of Valsalva. Data were obtained from 23 patients with symptomatic ventricular tachycardia or premature ventricular contractions (LV-VT) who underwent RF catheter ablation from the left sinus of Valsalva. Electrograms before and after application of RF energy during sinus rhythm and during LV-VT were analyzed. Complete elimination of LV-VT was finally achieved in 21 (91%) patients. The incidence of presystolic potentials preceding the QRS complex of LV-VT (P1 potential) was 90% for the 21 successful ablation sites, which did not differ from the incidence for the 24 unsuccessful sites (79%; P = 0.5). During sinus rhythm, a potential following the QRS complex (P2 potential) was more often recorded at the successful ablation site than at an unsuccessful ablation site before and after application of RF energy (before, P < 0.05; after, P < 0.001). The appearance of the P2 potential or a delay in the preexisting P2 potential after application of RF energy was observed only at the successful ablation sites (P < 0.001). In 18 control individuals who had no LV-VT, no P2 potential was recorded within the left sinus of Valsalva. Although the P1 potential may be useful for identifying the successful ablation site, its sensitivity is low. The appearance of the P2 potential or an increasingly delayed P2 potential after application of RF energy may be more useful than the P1 potential for predicting successful ablation.

Catheter Ablation↗

PubMed2004

Prevalence and characteristics of idiopathic outflow tract tachycardia with QRS alteration following catheter ablation requiring additional radiofrequency ablation at a different point in the outflow tract.

Subtle variations in QRS morphology occurs during idiopathic outflow tract ventricular tachycardia (OTVT), but no studies have clarified the prevalence and characteristics of the OTVT with altered QRS morphology following radiofrequency catheter ablation (RFA), which then require an additional RF application at a different portion of the outflow tract to abolish OTVT. Of 202 patients with a monomorphic VT or premature ventricular contraction (PVC) originating from the outflow tract, 6 (3%) showed changes in QRS morphology in the OTVT following RFA, requiring an additional RF application to the outflow tract at a different portion. In all six patients, RFA was applied for the first or second OTVT to a right or left ventricular endocardial site, with the other site being the left sinus of Valsalva. In each patient, OTVT before or after the changes in QRS morphology had characteristic ECG findings originating from a particular portion of the outflow tract. Changes in QRS morphology consistently included an increase or decrease in R wave amplitude in all inferior leads. Detailed continuous observation of QRS morphology in OTVT, especially R wave amplitude in inferior leads, is important for identifying changes of QRS morphology during catheter ablation. Mapping and ablation at a different portion of the outflow tract is then needed for cure.

Adult↗

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↗

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

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↗