Publications by authors named "Kaoru Takami"

Aims: Several algorithms can differentiate inferior axis premature ventricular contractions (PVCs) originating from the right side and left side on 12-lead electrocardiograms (ECGs). However, it is unclear whether distinguishing the origin should rely solely on PVC or incorporate sinus rhythm (SR). We compared the dual-rhythm model (incorporating both SR and PVC) to the PVC model (using PVC alone) and quantified the contribution of each ECG lead in predicting the PVC origin for each cardiac rotation.

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In persistent AF, the effect of adjunctive ablation in addition to PV isolation (PVI) is controversial. We considered a new modified PVI including complex fractionated atrial electrogram (CFAE) area. In 57 patients with persistent AF undergoing first ablation, CFAE were mapped before ablation and CFAE-guided extensive encircling PVI (CFAE-guided EEPVI) was performed.

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Background: Outcomes related to prophylactic catheter ablation (PCA) for ventricular tachycardia (VT) before implantable cardioverter-defibrillator (ICD) implantation in non-ischemic cardiomyopathy (NICM) are not well characterized. We assessed the efficacy of single endocardial PCA in NICM patients.

Methods: We retrospectively analyzed 101 consecutive NICM patients with sustained VT.

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Background: The upper limit of vulnerability (ULV) closely correlates with the defibrillation threshold (DFT). The aim of this study was to establish the optimal protocol for using the ULV test to predict high DFT (>20 J) without inducing ventricular fibrillation (VF).

Methods And Results: The 10-J and 15-J ULV test with 3 coupling intervals (-20, 0, and +20 ms to the peak of T-wave) and the DFT test were performed in 96 patients receiving implantable cardioverter defibrillator.

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Purpose: Dabigatran is effective for both the prevention of stroke and bleeding in patients with atrial fibrillation (AF). However, the safety and efficacy of the use of dabigatran in the peri-procedural period for radiofrequency catheter ablation (RFCA) of AF is unknown. Therefore, the purpose of this study was to evaluate the safety and efficacy of dabigatran in the peri-procedural period for RFCA of AF and the duration of hospital stay.

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Introduction: Conduction block in the posterior right atrium (RA) plays an important role in perpetuating atrial flutter (AFL). Although conduction blocks have functional properties, it is not clear how the block line changes with the pacing rate, pacing site, and administration of antiarrhythmic drugs.

Methods And Results: Forty patients with typical AFL were enrolled.

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Purpose: Slow pathway (SP) ablation of atrioventricular (AV) nodal reentrant tachycardia (AVNRT) can be complicated by unexpected AV block even at sites >10 mm inferior to the bundle of His (HB), and one cause is thought to be the inferior dislocation of an antegrade fast pathway (A-FP). We assessed locations of FPs guided by CARTO.

Methods: Sites of FPs were mapped guided by CARTO before SP ablation in 18 patients with slow-fast AVNRT.

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Background: Noncontact mapping is useful for the diagnosis of various arrhythmias. Virtual unipolar electrogram morphologies (VUEM) of the conduction block and the turnaround points, however, are not well defined. We compared the VUEM characteristics of a transverse conduction block in the posterior right atrium (RA) with those of contact bipolar electrograms obtained during typical atrial flutter (AFL).

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We describe a case of a 60-year-old male with dilated phase of hypertrophic cardiomyopathy caused by Fabry disease. He was diagnosed to have a cardiac variant of Fabry disease by an enzyme assay and a right ventricular endomyocardial biopsy which revealed specific features of this disease and cardiac involvement was the sole manifestation. He has developed dilated cardiomyopathy with sustained atrial flutter and frequent non-sustained ventricular tachycardia requiring isthmus ablation and cardiac resynchronization therapy with defibrillator.

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Background: The posteromedial right atrium (PMRA) forms a block line during typical atrial flutter (AFL). However, whether upper turnover portion exists at the anterior or posterior superior vena cava (SVC) has not been determined.

Methods: We performed right atrial mapping during AFL in 20 patients (typical AFL, n = 17; reverse typical AFL, n = 3) using an electroanatomical mapping system.

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We investigated the differences in the endocardial substrates between ischemic cardiomyopathy (ICM) and non-ICM (NICM) by using electro-anatomical mapping and pace-mapping. We studied 18 patients (ICM and NICM, 9 each) with monomorphic ventricular tachycardia (VT) documented by 12-leads ECG. Low voltage area was defined by signal amplitude <1.

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Background: The optimal left ventricle (LV) pacing site for cardiac resynchronization therapy (CRT) has been investigated, but less is known about the optimal site in the right ventricle (RV). The present study examined whether electrical resynchronization guided by electroanatomical mapping (CARTO) results in mechanical resynchronization.

Methods And Results: The study group included 13 patients indicated for CRT: 10 with nonischemic cardiomyopathy, 2 with ischemic cardiomyopathy and 1 with cardiac sarcoidosis, (mean LV ejection fraction: 32+/-10%).

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