Yukio Sekiguchi

University of Tsukuba, Tsukuba, Ibaraki, Japan

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Publications (107)408.13 Total impact

  • Takeshi Machino, Yukio Sekiguchi
    Circulation Journal 06/2015; DOI:10.1253/circj.CJ-15-0645 · 3.69 Impact Factor
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    ABSTRACT: We recently showed that the presence of J waves increases the risk of ventricular fibrillation (VF) occurrence in the early phase of an acute myocardial infarction (AMI). This study aimed to evaluate the clinical characteristics of VF occurrences in the early phase of an AMI between patients with and without J waves. This retrospective, observational study included 281 consecutive patients with an AMI (69±12 years; 207 men) in whom 12-lead ECGs before AMI onset could be evaluated. The patients were classified based on a VF occurrence <48 hours after AMI onset and the presence of J waves. J waves were electrocardiographically defined as an elevation of the terminal portion of the QRS complex of >0.1 mV from baseline in at least 2 contiguous inferior or lateral leads. VF occurred in 24 patients, and J waves were present in 37. VF occurrence was more prevalent in the patients with than without J waves (27% vs. 6%; p<0.001). Among the 244 patients without J waves, peak creatine kinase level (p<0.01), number of diseased coronary arteries (p<0.01), and male sex (p<0.05) were higher in the patients with than without VF occurrence. However, among the 37 patients with J waves, there was no significant difference in these variables. There was no association between the location of J waves and the infarct area. In patients with AMI, those with J waves were more likely to develop VF and less likely to have high-risk clinical characteristics than those without J waves. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Journal of Cardiovascular Electrophysiology 04/2015; DOI:10.1111/jce.12691 · 2.88 Impact Factor
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    ABSTRACT: The aims of this study were to clarify whether the ratio of S- to R-flecainide (S/R ratio) in the serum flecainide concentration was associated with the stereoselectivity of flecainide metabolism, and to investigate the effects of the cytochrome P450 (CYP) 2D6 (CYP2D6) genotype and CYP2D6 inhibitor on the serum flecainide S/R ratio. In vitro studies using human liver microsomes and cDNA-expressed CYP isoforms suggested that variability in the serum flecainide S/R ratio was associated with the stereoselectivity of CYP2D6-mediated flecainide metabolism. We examined the serum flecainide S/R ratio in 143 patients with supraventricular tachyarrhythmia. The S/R ratio was significantly lower in intermediate metabolizers and poor metabolizers (IMs/PMs) than in extensive metabolizers (EMs) identified by the CYP2D6 genotype. The cut-off value for the S/R ratio to allow the discrimination between CYP2D6 EMs and IMs/PMs was 0.99. The S/R ratio in patients with co-administration of bepridil, a potent CYP2D6 inhibitor, was lower than 0.99, regardless of the CYP2D6 genotype status. Other factors, including age, sex, body weight, and renal function, did not affect the serum flecainide S/R ratio. This study suggests that the serum flecainide S/R ratio reflects the CYP2D6 genotype and changes in CYP2D6 activity on co-administration of a CYP2D6 inhibitor. Copyright © 2015 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.
    Drug Metabolism and Pharmacokinetics 04/2015; DOI:10.1016/j.dmpk.2015.04.001 · 2.86 Impact Factor
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    ABSTRACT: On the basis of the electromechanical coupling theory, an activation imaging system has been developed with three-dimensional speckle-tracking echocardiography. The aim of this study was to determine the association between left ventricular (LV) propagation patterns by activation imaging and response to cardiac resynchronization therapy (CRT). This was a retrospective, single-center study. Eighty-one patients undergoing CRT, of whom 50 (61.7%) had left bundle branch block (LBBB), were enrolled. Activation imaging studies were performed with a three-dimensional speckle-tracking echocardiographic system, which allowed visualization of LV activation propagation and measurement of the time from the QRS complex to activation onset. A CRT volume responder was defined as a patient with ≥15% reduction of LV end-systolic volume at 6 months after CRT. Clinical outcomes were assessed with the composite end point of death due to cardiac causes or unplanned hospitalization for cardiac diseases. In patients with LBBB, the main activation pattern (74%) was a U-shaped propagation pattern, which was characterized as propagation from the midseptum to the lateral or posterior wall through the apex. In patients without LBBB, various non-U-shaped propagation patterns were observed in the majority of patients (97%). Among the 41 CRT responders, almost all (87.8%) had the U-shaped propagation pattern. During follow-up (median, 20 months), 29 patients (35.8%) reached the clinical end points. In a multivariate Cox proportional hazards model, a U-shaped propagation pattern was associated with the end points independently of LBBB or LV end-diastolic volume. The U-shaped propagation pattern on three-dimensional speckle-tracking echocardiography was significantly associated with a favorable CRT response. Activation pattern analysis may provide additional information to predict response to CRT. Copyright © 2015 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.
    Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 03/2015; 28(5). DOI:10.1016/j.echo.2015.02.003 · 3.99 Impact Factor
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    ABSTRACT: -In patients with mechanical aortic and mitral valves and left ventricular tachycardia (VT) catheter ablation may be prevented by limited access to the left ventricle. -In our series of six patients, two patients underwent direct surgical ablation and four underwent epicardial catheter ablation via a pericardial window. All patients had abnormal low voltage areas with fractionated or delayed isolated potentials on the apical epicardium. Most of the VTs were targeted by pace mapping. Sites with a good pace match or abnormal electrograms were ablated using an irrigated RF ablation catheter. A microscopic pathological evaluation of the resected tissue from two of the open-heart ablation patients revealed dense fibrosis on the epicardium as compared to the endocardium, supporting the feasibility of an epicardial ablation for the VT. -Epicardial catheter ablation of VT is a potentially useful therapy in patients who have mechanical aortic and mitral valves.
    Circulation Arrhythmia and Electrophysiology 02/2015; 8(2). DOI:10.1161/CIRCEP.114.002517 · 5.42 Impact Factor
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    ABSTRACT: There are many reports on the ECG characteristics of idiopathic outflow tract ventricular arrhythmias (OT-VAs) to predict their origin. However, differentiating near regions using 12-lead ECGs is still complicated. The synthesized 18-lead ECG derived from the 12-lead ECG can provide virtual waveforms of the right-sided chest leads (V3R, V4R, and V5R) and back leads (V7, V8, and V9). The aim of this study was to develop a simple and useful parameter for differentiating OT-VA origins using the 18-lead ECG. We studied 28 and 73 patients with idiopathic VAs in a pacemapping study and validation cohort, respectively. In the pacemapping study, several sites out of five different sites were paced in each patient: the anterior and posterior right ventricular OT (RVOT-ant and RVOT-post), right and left coronary cusps (RCC and LCC), and junction of both cusps (RLJ). The 18-lead ECGs during pacemapping among the five sites were compared for establishing a simple parameter to predict VA origins. A novel parameter using 18-lead ECGs was tested prospectively in 73 patients. In the pacemapping study, the dominant QRS morphology pattern in the synthesized V5R significantly differed among those sites (RVOT-ant:Rs, RVOT-post:rS, RCC:QS, RLJ:qR, and LCC:R). The patients in the validation cohort were divided into five groups depending on those QRS morphology patterns during VAs in the synthesized V5R. Each V5R QRS morphology pattern could predict a precise origin of the OT-VAs with an overall accuracy of 75%. The QRS morphology pattern in V5R was a simple and useful parameter for differentiating detailed OT-VA origins. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.
    Europace 01/2015; DOI:10.1093/europace/euu337 · 3.05 Impact Factor
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    ABSTRACT: -Septal atrial tachycardia (AT) can occur in patients without structural heart disease and in patients with prior catheter ablation of atrial fibrillation. We aimed to assess septal AT that occurs after open-heart surgery. -This study comprised 20 consecutive patients undergoing catheter ablation of macroreentrant AT after open-heart surgery. Relevance to surgical approach, mechanisms, anatomical and electrophysiological characteristics, and outcomes were assessed. Septal AT was identified in 7 patients who had all undergone mitral valve surgery. All septal ATs were localized in the left atrial septum, whereas 10 of 13 non-septal ATs originated from the right atrium. Patients with left septal AT had a thicker fossa ovalis (median: 4.0, 25(th)-75(th) percentile: 3.6-4.2 vs 2.3, 1.6-2.6 mm, p=0.006) and broader area of low voltage (<0.3 mV) in the septum than patients with non-septal AT (82, 76-89 vs 31, 28-36%, p=0.02). Repeated gradual prolongations of the tachycardia cycle length without change of the septal circuit was observed in all patients with septal AT (70, 63-100 vs 15, 10-40 ms, p=0.0008). Although ablation terminated all ATs, recurrence of targeted ATs was more frequent in patients with left septal AT during 30-month follow-up (71 vs 0%, p=0.001). -Left septal AT after open-heart surgery was characterized by a thicker septum, more scar burden in the septum, and repeated prolongations of the tachycardia cycle length during ablation. Such an arrhythmogenic substrate may interfere with transmural lesion formation by ablation and may account for higher likelihood of recurrence of left septal AT.
    Circulation Arrhythmia and Electrophysiology 11/2014; 8(1). DOI:10.1161/CIRCEP.114.001680 · 5.42 Impact Factor
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    ABSTRACT: Aims The long-term prognosis of subjects with supraventricular premature complexes (SVPCs) remains unclear in the general population. The aim of this study was to examine the prognostic significance of SVPCs in community-based health checkups. Methods and results We assessed 63 197 individuals (mean age, 58.8 ± 9.9 years; 67.6% women) who participated in annual community-based health checkups in 1993 and were followed until 2008. The primary endpoint was stroke death, cardiovascular death (CVD), or all-cause death during a 14-year mean follow-up, and the secondary endpoint was first atrial fibrillation (AF) event in subjects without self-reported heart diseases or AF at baseline. Compared with subjects without SVPCs, the multivariate-adjusted hazard ratios (HRs) [95% confidence interval (CI)] of stroke death, CVD, and all-cause death in subjects with SVPCs were 1.24 (0.98-1.56) for men and 1.63 (1.30-2.05) for women, 1.22 (1.04-1.44) for men and 1.48 (1.25-1.74) for women, and 1.08 (0.99-1.18) for men and 1.21 (1.09-1.34) for women, respectively. Atrial fibrillation occurred in 386 subjects during the follow-up (1.05/1000 person-years). The presence of SVPCs at baseline was the significant predictor of AF onset [HRs (95% CI): 4.87 (3.61-6.57) for men and 3.87 (2.69-5.57) for women]. Propensity score matched analyses also revealed the presence of SVPCs was significantly associated with increased risks of AF incidence and CVD even after adjusting the potential confounders. Conclusion The presence of SVPCs in 12-lead electrocardiograms was a strong predictor of AF development, and associated with increased risk of CVD in general population. © Published on behalf of the European Society of Cardiology. All rights reserved.
    European Heart Journal 10/2014; 36(3). DOI:10.1093/eurheartj/ehu407 · 14.72 Impact Factor
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    ABSTRACT: Background The HRS/EHRA/APHRS Expert Consensus Statement for implantable cardioverter defibrillator (ICD) in Brugada syndrome (BrS) has recently been published. The validity of the Class II indication for ICD is still unknown in BrS patients. Objective To evaluate the validity of the Class II indication for ICD implantation in the Consensus Statement with a large Japanese cohort of BrS. Methods Out of 410 patients with Brugada syndrome, a total of 213 consecutive BrS patients with the Class II indication for ICD implantation (mean age 53± 14 years, 199 men) were enrolled. Clinical outcomes were compared between patients with Class IIa (n = 66) and Class IIb (n = 147) indication according to the Consensus Statement. Results The incidence of cardiac events (documented ventricular tachycarrhythmias or sudden cardiac death) during follow-up of 62 ± 34 months was significantly higher in patients with Class IIa (n = 8, 2.2%/yr) than those with Class IIb indication (n = 4, 0.5%/yr) (p = 0.01). Conclusions We confirmed Class IIa indication identified a group of patients with increased risk compared to Class IIb indication for ICD in the Consensus Statement of 2013. In patients with Class II indication, the combination of a history of syncope and spontaneous type-1 ECG may be an important factor to distinguish intermediate- from low-risk patients with BrS in Japan.
    Heart Rhythm 10/2014; 11(10). DOI:10.1016/j.hrthm.2014.06.033 · 4.92 Impact Factor
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    ABSTRACT: Stereoselective analyses of flecainide enantiomers were performed using reversed-phase high-performance liquid chromatography (HPLC) equipped with a polysaccharide-based chiral column (Chiralpak AS-RH) and fluorescence detector. Excitation and emission wavelengths were set at 300 and 370 nm, respectively. Flecainide enantiomers in serum and urine were extracted using diethyl ether. The mobile phase solution, comprising 0.1 m potassium hexafluorophosphate and acetonitrile (65:35, v/v), was pumped at a flow rate of 0.5 mL/min. The recoveries of flecainide enantiomers were greater than 94%, with the coefficients of variation (CVs) <6%. The calibration curves of flecainide enantiomers in serum and urine were linear in the concentration range 5-500 ng/mL and 0.75-15 µg/mL (r > 0.999), respectively. CVs in intra-day and inter-day assays were 1.8-5.8 and 3.4-7.5%, respectively. In a pharmacokinetic study, the ratios of (S)- to (R)-flecainide (S/R ratio) in the area under the curve and the amount of flecainide enantiomers excreted in urine were lower in a subject carrying CYP2D6*10/*10 than in subjects carrying CYP2D6*1/*2. The S/R ratio of trough serum flecainide concentration ranged from 0.79 to 1.16 in patients receiving oral flecainide. The present HPLC method can be used to assess hepatic flecainide metabolism in a pharmacokinetic study and therapeutic drug monitoring. Copyright © 2014 John Wiley & Sons, Ltd.
    Biomedical Chromatography 09/2014; 28(9). DOI:10.1002/bmc.3143 · 1.66 Impact Factor
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    ABSTRACT: Background To determine an appropriate M-mode method in assessing left ventricular (LV) dyssynchrony in left bundle branch block (LBBB), and to assess feasibility of the method to predict cardiac resynchronization therapy (CRT) responses. Methods and results Fifty-one patients with LBBB were enrolled. Among them 31 patients underwent CRT. In addition to original septal to posterior wall motion delay (SPWMD), first peak-SPWMD was proposed as time of difference between the first septal displacement and the maximum displacement of the posterior. If an early septal point was not present, anatomical M-mode was used to visualize an early septal displacement spreading scan-area until inferoseptal wall. CRT responders were defined as LV end-systolic volume reduction (>15%) at 6 months after CRT. Twenty patients (65%) were identified as CRT responders. First peak-SPWMD in responders was significantly higher than those in nonresponders, although SPWMD did not differ between groups. Strong predicting ability of first peak-SPWMD was revealed (first peak-SPWMD: 80/90/83%; SPWMD: 35/100/58%), and area under the curve in receiver operating characteristic analysis of first peak-SPWMD (0.88) was significantly higher than that of SPWMD (0.61) (p < 0.05). Conclusion In patients with LBBB, time differences between early septal and delayed displacement of posterolateral wall on M-mode images were the appropriate dyssynchrony parameter, and could improve the predictive ability for CRT responses.
    Journal of Cardiology 09/2014; 64(3-4). DOI:10.1016/j.jjcc.2013.12.013 · 2.57 Impact Factor
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    ABSTRACT: BACKGROUND Although several reports address characteristic 12-lead electrocardiographic findings of outflow tract ventricular arrhythmias (OT-VAs), the accuracy of electrocardiogram-based algorithms to predict the OT-VA origin is sometimes limited. OBJECTIVE This study aimed to develop a magnetocardiography (MCG) based algorithm using a novel adaptive spatial filter to differentiate between VAs originating from the aortic sinus cusp (ASC-VAs) and those originating from the right ventricular outflow tract (RVOT-VAs). METHODS This study comprised 51 patients with an OT-VA as the target of catheter ablation. An algorithm was developed by correlating MCG findings with the successful ablation site. The arrhythmias were classified as RVOT-VAs or ASC-VAs. Three parameters were obtained from 3-dimensional MCG imaging: depth of the origin of the OT-VA in the anteroposterior direction; distance between the earliest atrial activation site, that is, sinus node, and the origin of the OT-VA; and orientation of the arrhythmia propagation at the QRS peak. The distance was indexed to the patient's body surface area (in mm/m(2)). RESULTS Origins of ASC-VAs were significantly deeper (81 +/- 6 mm/m(2) vs 68 +/- 8 mm/m(2); P < .01) and farther from the sinus node (55 +/- 9 mm/m(2) vs 41 9 mm/m(2); P < .01) than those of RVOT-VAs. ASC-VA propagation had a tendency toward rightward axis. Receiver operating characteristic analyses determined that the depth of the origin was the most powerful predictor, with a sensitivity of 90% and a specificity of 73% (area under the curve = 0.90; P < .01). Discriminant analysis combining all 3 parameters revealed the accuracy of the localization to be 94%. CONCLUSION This MCG-based algorithm appeared to precisely discriminate ASC-VAs from RVOT-VAs. Further investigation is required to validate the clinical value of this technique.
    Heart rhythm: the official journal of the Heart Rhythm Society 05/2014; 11(9). DOI:10.1016/j.hrthm.2014.05.032 · 4.92 Impact Factor
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    ABSTRACT: Background-We recently showed that the presence of early repolarization (ER) increases the risk of ventricular fibrillation occurrences in the early phase of acute myocardial infarction (AMI). This study aimed to clarify whether an association exists between ER and occurrences of ventricular tachyarrhythmias or sudden death in the chronic phase of AMI. Methods and Results-This study retrospectively enrolled 1131 patients (67+/-12 years; 862 men) with AMIs surviving 14 days post-AMI. The primary end point was the occurrence of sustained ventricular tachyarrhythmias or sudden death >14 days after the AMI onset. We evaluated the presence of ER from the predischarge ECG (mean 10+/-3 days post-AMI). ER was defined as an elevation of the terminal portion of the QRS complex of >0.1 mV in inferior or lateral leads. After a median follow-up of 26.2 months, 26 patients had an episode of ventricular tachyarrhythmias or sudden death. A multivariable Cox regression analysis revealed the presence of ER (hazard ratio, 5.37; 95% confidence interval, 2.27-12.69; P<0.001), Killip class on admission of >I (hazard ratio, 2.75; 95% confidence interval, 1.24-6.07; P=0.013), and a left ventricular ejection fraction of <35% (hazard ratio, 11.83; 95% confidence interval, 5.16-27.13; P<0.001) were significantly associated with event occurrences. As features of the ER pattern, ER in the inferior leads, high-amplitude ER, a notched morphology, and ER without ST-segment elevation were associated with an increased risk of event occurrences. Conclusions-ER observed at a mean of 10 days post-AMI may be a marker for a subsequent risk of ventricular tachyarrhythmias or sudden death.
    Circulation Arrhythmia and Electrophysiology 05/2014; 7(4). DOI:10.1161/CIRCEP.113.000939 · 5.42 Impact Factor
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    ABSTRACT: Background Fatal arrhythmia is commonly observed in cardiac sarcoidosis, but clinical effects of a systematic treatment approach are still uncertain. This study sought to describe both clinical and electrophysiological characteristics and outcomes of systematic treatment approach to ventricular tachycardia (VT) associated with cardiac sarcoidosis. Methods and Results We enrolled 37 consecutive patients (11 men; age, 5611 years) with a diagnosis of sustained VT associated with cardiac sarcoidosis. Clinical effects of a systematic treatment approach including medical therapy (both steroid and antiarrhythmic agents), in association with radiofrequency catheter ablation, were evaluated. All patients received antiarrhythmic agents, and 34 received steroid therapy. During a 39-month follow-up, 23 (62%) patients were free from any VT episodes with medical therapy. Multivariable Cox regression analyses revealed that the absence of gallium-67 myocardial uptake was an independent predictor for VT recurrence (hazard ratio, 7.51; 95% confidence interval, 1.65-34.26; P<0.01). Fourteen patients who experienced VT recurrences even while on drug therapy underwent radiofrequency catheter ablation. Electrophysiological study revealed that the mechanisms of VTs could be classified into 2 subgroups: Purkinje-related or scar-related VT. The QRS duration of VT was narrower in Purkinje-related than in scar-related VTs (157 +/- 23 versus 183 +/- 22 ms; P<0.05). After a 33-month follow-up subsequent to the radiofrequency catheter ablation, 6 of 14 patients experienced VT recurrence. The number of VTs sustained during electrophysiological study was higher in the patients with VT recurrence than in those without (3.7 +/- 1.4 versus 1.9 +/- 0.8; P<0.01). Conclusions A systematic treatment approach to cardiac sarcoidosis with VT successfully suppressed VT recurrences in the majority of patients studied.
    Circulation Arrhythmia and Electrophysiology 05/2014; 7(3). DOI:10.1161/CIRCEP.113.000734 · 5.42 Impact Factor
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    ABSTRACT: Although radiofrequency ablation creates myocardial necrosis leading to troponin T (TnT) release into the systemic circulation, the significance of TnT elevation after atrial fibrillation (AF) ablation is unknown. To demonstrate a possible mechanism of reverse structural remodeling in the left atrium (LA) by evaluating post-procedure TnT elevation. This study included 106 patients with an enlarged LA (paroxysmal AF, n=43; persistent AF, n=63). All patients underwent pulmonary vein isolation alone in the index procedure. LA volume indexed to body surface area (LAVi) was measured by echocardiography before ablation and 6 months after sinus rhythm restoration. Patients were divided into responders (n=53) or nonresponders (n=53) based on a cut-off value of 23% reduction in LAVi. TnT was measured 12 hours post procedure. LAVi decreased from 43±13 to 33±12 mL/m(2) (P<0.0001). TnT level was higher in responders than in nonresponders (1.31±0.34 vs 0.88±0.29 μg/L, P<0.0001) and correlated linearly with % reduction in LAVi (R=0.54, P<0.0001). Also in multivariate analysis, TnT level was the only independent predictor for responders (OR, 90.1; 95% CI 14.95-543.3; P<0.0001). TnT level in patients who required a repeat procedure (n=30) was lower than that in patients who did not only in the persistent AF group (0.92±0.38 vs 1.16±0.37 μg/L, P=0.01). Greater elevation of TnT level was related both to favorable outcomes after ablation and to greater reversal of structural remodeling. Post-procedure TnT level may be reflective of the preservation of healthy LA myocardium.
    Heart rhythm: the official journal of the Heart Rhythm Society 04/2014; 11(8). DOI:10.1016/j.hrthm.2014.04.015 · 4.92 Impact Factor
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    ABSTRACT: Background Although radiofrequency ablation creates myocardial necrosis leading to troponin T (TnT) release into the systemic circulation, the significance of TnT elevation after atrial fibrillation (AF) ablation is unknown. Objective To demonstrate a possible mechanism of reverse structural remodeling in the left atrium (LA) by evaluating post-procedure TnT elevation. Methods This study included 106 patients with an enlarged LA (paroxysmal AF, n=43; persistent AF, n=63). All patients underwent pulmonary vein isolation alone in the index procedure. LA volume indexed to body surface area (LAVi) was measured by echocardiography before ablation and 6 months after sinus rhythm restoration. Patients were divided into responders (n=53) or nonresponders (n=53) based on a cut-off value of 23% reduction in LAVi. TnT was measured 12 hours post procedure. Results LAVi decreased from 43±13 to 33±12 mL/m2 (P<0.0001). TnT level was higher in responders than in nonresponders (1.31±0.34 vs 0.88±0.29 μg/L, P<0.0001) and correlated linearly with % reduction in LAVi (R=0.54, P<0.0001). Also in multivariate analysis, TnT level was the only independent predictor for responders (OR, 90.1; 95% CI 14.95–543.3; P<0.0001). TnT level in patients who required a repeat procedure (n=30) was lower than that in patients who did not only in the persistent AF group (0.92±0.38 vs 1.16±0.37 μg/L, P=0.01). Conclusion Greater elevation of TnT level was related both to favorable outcomes after ablation and to greater reversal of structural remodeling. Post-procedure TnT level may be reflective of the preservation of healthy LA myocardium.
    Journal of the American College of Cardiology 04/2014; 63(12). DOI:10.1016/S0735-1097(14)60401-0 · 15.34 Impact Factor
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    ABSTRACT: The present case report describes a 53-year-old man with drug-resistant heart failure. Electrocardiogram showed complete right-bundle branch block and left anterior fascicular block. A cardiac resynchronization therapy (CRT) device was implanted in him because echocardiography showed obvious left ventricular dyssynchrony between septal and lateral walls. After CRT implantation, dyssynchrony was improved and ejection fraction was increased. Evaluation of coexisting left hemiblock and left ventricular dyssynchrony may be needed in patients with atypical indications for CRT. <Learning objective: Cardiac resynchronization therapy (CRT) for patients with complete right-bundle branch block (CRBBB) is still controversial. Presence of hemiblock and left ventricular dyssynchrony between the pacing sites may be essential to determine CRT indication even in patients with CRBBB.
    Journal of Cardiology Cases 04/2014; 9(4). DOI:10.1016/j.jccase.2013.12.013
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    ABSTRACT: Radiofrequency catheter ablation of an atrial tachycardia (AT) and atrial fibrillation (AF) was performed in a patient with a history of pulmonary vein isolation for paroxysmal AF. The AT exhibited a centrifugal pattern with the posterolateral LA as the earliest activation site. The AT was not terminated by ablation at the endocardial earliest site, but its cycle length was prolonged by ablation at an opposite site within the Vein of Marshall. Finally, the AT was terminated by an energy application at a site 7 mm posteroinferior to the initial earliest activation site. We analyzed the local potentials of each energy delivery site in detail.
    Heart and Vessels 04/2014; 30(3). DOI:10.1007/s00380-014-0498-3 · 2.11 Impact Factor
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    ABSTRACT: Background: Linear ablation of atrial flutter usually targets a 6 o'clock position on the cavotricuspid isthmus on left anterior oblique view, but the difficulty of the ablation often requires a variation in successful ablation line position from 5 to 7 o'clock. Methods and Results: This study included 94 patients without structural heart disease. A linear lesion was created in turn at the 6, 7, and 5 o'clock positions until bidirectional block of the isthmus was completed; the final lesion was defined as the successful ablation line. The degree of counterclockwise heart rotation (CCW-HR) was evaluated in a blinded fashion according to the angle between the vertical line crossing the His bundle catheter and the line connecting the His bundle catheter and coronary sinus ostium. Successful ablation lines were obtained at the 6 o'clock position in 59 patients (63%); the 7 o'clock position in 19 patients (20%; the oldest group with a moderate radiofrequency burden); and the 5 o'clock position in the remaining 16 (17%; the youngest group with the largest radiofrequency burden). Age-related increase in CCW-HR was the only independent predictor of a more septal successful ablation line (OR, 7.1; 95% CI: 3.3-14.3; P<0.01). Conclusions: Variation in successful ablation line position was affected by age-related CCW-HR; its evaluation might reduce radiofrequency burden, especially in the young and elderly.
    Circulation Journal 02/2014; 78(4). DOI:10.1253/circj.CJ-13-1077 · 3.69 Impact Factor
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    ABSTRACT: -In patients with atrial fibrillation (AF), most thrombus forms in the left atrial appendage (LAA). However, the relation of LAA morphology with LAA thrombus is unknown. -We prospectively enrolled 633 consecutive patients who were candidates for catheter ablation for symptomatic drug-resistant AF. Transesophageal echocardiography (TEE) was performed to assess LAA thrombus. LAA structure was assessed by three-dimensional TEE. LAA orifice area, depth, volume, and number of lobes were measured on reconstructed three-dimensional images. Clinical characteristics and echocardiographic measures were compared to determine variables predicting LAA thrombus. Excluded were 69 (10.9%) patients who met the exclusion criteria. Finally, this study comprised 564 patients in whom LAA thrombus was observed in 36 (6.4%) patients. Multivariate analysis revealed CHADS2 score (P=0.002), left ventricular ejection fraction (P=0.01), degree of spontaneous echo contrast (P=0.02), left atrial volume (P=0.02), and number of LAA lobes (P<0.001) to be independently associated with thrombus formation. Most patients with LAA thrombus (32/34, 94.4%) had ≥3 LAA lobes, whereas LAA thrombus was observed in only 2 (0.7%) of 296 patients with 1 or 2 lobes. LAA volume significantly decreased in patients maintaining sinus rhythm after catheter ablation (P=0.0009). Number of LAA lobes did not change in any patient. -Complex LAA morphology characterized by an increased number of LAA lobes was associated with the presence of LAA thrombus, independently of clinical risk and blood stasis. This study suggests that LAA morphology might be a congenital risk factor for LAA thrombus formation in patients with AF.
    Circulation Cardiovascular Imaging 02/2014; 7(2). DOI:10.1161/CIRCIMAGING.113.001317 · 6.75 Impact Factor

Publication Stats

721 Citations
408.13 Total Impact Points

Institutions

  • 2006–2015
    • University of Tsukuba
      • • Department of Cardiovascular Surgery
      • • Institute of Clinical Medicine
      Tsukuba, Ibaraki, Japan
  • 2012
    • Osaka City University
      • Graduate School of Medicine
      Ōsaka, Ōsaka, Japan
  • 2009
    • Philadelphia ZOO
      Filadelfia, Pennsylvania, United States
  • 2005
    • Musashino Red Cross Hospital
      Edo, Tōkyō, Japan
    • National Cerebral and Cardiovascular Center
      Ōsaka, Ōsaka, Japan