Makoto Hirai

Social Insurance Chukyo Hospital, Nagoya, Aichi, Japan

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Publications (100)412.55 Total impact

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    ABSTRACT: Patients with greater improvement of cardiac function after cardiac resynchronization therapy (CRT) implantation are identified as "super-responders." However, it remains unclear which kind of preimplant assessments could accurately predict outcomes after CRT. Thus, we aimed to examine the essential predicting factors for super-response to CRT, and to construct an accurate predictable model.
    Pacing and Clinical Electrophysiology 09/2014; · 1.75 Impact Factor
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    ABSTRACT: Background Several algorithms for localizing accessory pathways (APs) are based on the delta wave morphology, R/S ratio, and QRS polarity. However, they are somewhat complicated, and an accurate determination of the delta wave morphology is occasionally difficult. The aims of this study were to develop a simple algorithm for localizing APs using only the R/S ratio, and to test the accuracy of the algorithm prospectively. Methods We studied 142 patients with a single anterogradely conducting AP on a 12-lead ECG. R/S ratios were analyzed in leads V1, V2, and aVF (R/S-V1, R/S-V2, and R/S-aVF). AP locations were divided into five regions based on fluoroscopic anatomy. Results A new algorithm was developed by correlating R/S-V1, R/S-V2, and R/S-aVF with successful ablation sites in 88 initial consecutive patients. All 55 patients with left free wall APs showed R/S-V1 ≥0.5, and 47 (98%) of 48 patients with left anterior or lateral APs showed R/S-aVF ≥1. In contrast, all seven patients with left posterolateral or posterior APs showed R/S-aVF <1. All nine patients with right-and-left midseptal or posteroseptal APs showed R/S-V1 <0.5 and R/S-V2 ≥0.5. Of 12 patients with right anterior, lateral or anteroseptal APs, 10 (83%) showed R/S-V1 <0.5, R/S-V2 <0.5 and R/S-aVF ≥1. Finally, nine (75%) of 12 patients with right posterolateral or posterior APs showed R/S-V1 <0.5, R/S-V2 <0.5, and R/S-aVF <1. Then this algorithm was tested prospectively in 54 patients. Overall, the sensitivity was 94%, and the specificity was 98%. Conclusions This ECG algorithm provides a simple and accurate way to identify the AP localization.
    Journal of Arrhythmia 12/2013;
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    ABSTRACT: Background: In recent years, there has been a series of recalls of popular implantable cardioverter defibrillators leads, and several reports have demonstrated an increasing rate of failure of such leads over time in Caucasian patients. However, little is known about the performance of these leads in Asian patients. The aim of this study was to investigate the rate of failure of the recalled leads and the characteristics as compared with non-recalled leads in Japanese patients. Methods and Results: A retrospective chart review was conducted in 214 patients (75 Sprint Fidelis, 8 Riata, and 131 Sprint Quattro leads) who underwent implantation and follow-up at Nagoya University Hospital. During the follow-up period, 14 Sprint Fidelis leads (19%) and 1 Riata lead (13%) failed, but no abnormality was found in the Sprint Quattro, non-recalled leads. Five patients (4 Sprint Fidelis and 1 Riata, 33% of lead failure patients) received inappropriate shocks. The 3-, 4-, and 5-year lead survival rates in Sprint Fidelis leads were 95.1% (95% confidence interval [CI]: 89.6%-100%), 89.8% (95% CI: 82.1%-97.6%), and 88.0% (95% CI: 79.6%-96.4%), respectively. A previous device implantation before Sprint Fidelis lead was the only significant predictor for lead fracture (hazard ratio, 5.33; 95% CI: 1.55-18.4; P=0.008). Conclusions: The rate of Sprint Fidelis lead failure continues to increase over time in Japanese patients.
    Circulation Journal 11/2013; · 3.58 Impact Factor
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    ABSTRACT: Background: Cardiac resynchronization therapy (CRT) has been reported to improve symptoms and cardiac performance in patients with severe heart failure (HF), but CRT recipients with advanced HF do not always experience improved mortality rates. Cystatin C has recently been involved in HF, but the association of serum cystatin C level with adverse events and long-term prognosis after CRT is unknown. This study investigated whether cystatin C level can predict mortality and cardiovascular events after CRT. Methods and Results: A total of 117 consecutive patients receiving a CRT device for the treatment of advanced HF were assessed according to cystatin C level and long-term outcome after implantation of the device. Over a median follow-up of 3.2 years, 34 patients (29.1%) died and 59 patients (50.4%) developed cardiovascular events. Kaplan-Meier survival analysis indicated that elevated cystatin C level was significantly associated with higher all-cause mortality and prevalence of cardiovascular events, including hospitalization for progressive HF. After multivariate Cox regression analysis, serum cystatin C level and QRS duration, but not conventional echocardiographic parameters, were found to independently predict all-cause death or cardiovascular events. Of importance, only cystatin C level was an independent predictor of all-cause mortality after CRT. Conclusions: Cystatin C level independently predicts cardiac mortality or morbidity in patients receiving CRT. The assessment of cystatin C level could provide valuable information about long-term prognosis after CRT.
    Circulation Journal 08/2013; · 3.58 Impact Factor
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    ABSTRACT: To differentiate acute from chronic damage to the myocardium in patients with myocardial infarction (MI) using DE and T2w MR. Short-axis T2w and DE MR images were acquired twice after the onset of MI in 36 patients who successfully underwent emergency coronary revascularisation. The areas of infarct and oedema were measured. The oedema-infarct ratio (O/I) of the left ventricular area was calculated by dividing the oedema by the infarct area. The oedema size on T2w MR was significantly larger than the infarct size on DE MR in the acute phase. Both the oedema size on T2w MR and the infarct size on DE MR in the acute phase were significantly larger than those in the chronic phase. The O/I was significantly greater in the acute phase compared with that in the chronic phase (P < 0.05). An analysis of relative cumulative frequency distributions revealed an O/I of 1.4 as a cut-off value for differentiating acute from chronic myocardial damage with the sensitivity, specificity, and accuracy of 85.1%, 82.7% and 83.9%, respectively. The oedema-infarct ratio may be a useful index in differentiating acute from chronic myocardial damage in patients with MI. MR can differentiate reversible from irreversible myocardial damage after myocardial infarction. MR is a useful modality to noninvasively differentiate the infarct stages. The O/I is an important index to decide therapeutic strategies.
    European Radiology 12/2011; 22(4):789-95. · 4.34 Impact Factor
  • Heart Rhythm 12/2011; 8(12):e15. · 5.05 Impact Factor
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    ABSTRACT: Although the circadian variation of catecholamine has been reported, that of the pulse wave velocity (PWV) has not. Brachial ankle (ba) PWV is associated with well-established indices of central stiffness. It is not known whether arterial stiffness is associated with catecholamine. The aim of the present study was to evaluate the changes in baPWV and those on the plasma epinephrine and norepinephrine levels in the morning and evening in hypertensive patients (HPs) and normotensive subjects (NSs). The baPWV and blood pressure (BP) were measured in 14 NSs (14 males, 39 ± 5 years) and 10 HPs (9 males and 1 female, 55 ± 13 years) at 06:00 h, noon, 18:00 h, and midnight, respectively. The plasma epinephrine and norepinephrine levels were measured in 14 NSs and 5 HPs at 06:00 h and 18:00 h, respectively. There was no significant difference in BPs at 06:00 h, noon, 18:00 h, and midnight in either NSs or HPs. The baPWV at 06:00 h was significantly lower than that at noon, 18:00 h, and midnight in NSs (P = 0.01, 0.04, and 0.0008, respectively). The plasma epinephrine and norepinephrine levels at 06:00 h were markedly lower than those at 18:00 h in NSs (P = 0.002 and 0.003, respectively). There were no significant changes in the baPWV of HPs at 06:00 h, noon, 18:00 h, or midnight. The plasma epinephrine and norepinephrine levels at 06:00 h were notably lower than those at 18:00 h in HPs (P = 0.004 and 0.01, respectively). Only NSs showed a significant reduction in the baPWV with a decrease in the plasma catecholamine levels in the morning, suggesting that the baPWV of NSs may be correlated with the variation of the plasma catecholamine levels.
    Heart and Vessels 10/2011; 27(5):493-8. · 2.13 Impact Factor
  • Heart rhythm: the official journal of the Heart Rhythm Society 10/2011; · 4.56 Impact Factor
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    ABSTRACT: Although several ECG algorithms have been proposed for differentiating the origins of outflow tract ventricular arrhythmia (OT-VA), their accuracy still is limited in cases with cardiac rotation. The purpose of this study was to assess whether a novel "cardiac rotation-corrected" transitional zone (TZ) index would be a useful marker for differentiating right ventricular outflow tract (RVOT) origin from aortic sinus cusp (ASC) origin. Surface ECGs of OT-VAs with left bundle branch block morphology and inferior axis in 112 patients who were successfully ablated in the RVOT (n = 87) or the ASC (n = 25) were analyzed. The TZ index was defined according to the site of R-wave transition of sinus beats and OT-VAs. The TZ index was significantly lower in the ASC origin than in the RVOT origin (-1.2 ± 0.9 vs 0.3 ± 0.7, P <.0001). A cutoff value of the TZ index <0 predicted the ASC origin with 88% sensitivity and 82% specificity. The previously reported R-wave duration index ≥ 50% had a high specificity of 85% but a low sensitivity of 44%, and R/S-wave amplitude index ≥ 30% had 68% sensitivity and 79% specificity. The area under the curve by receiver operating characteristic curve analysis was 0.90 for the TZ index, which was significantly higher than the R-wave duration index and R/S-wave amplitude index of 0.74 and 0.76, respectively. This novel TZ index can be a more useful marker for differentiating RVOT origin from ASC origin.
    Heart rhythm: the official journal of the Heart Rhythm Society 11/2010; 8(3):349-56. · 4.56 Impact Factor
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    ABSTRACT: Mechanical dyssynchrony is an important factor in the response to cardiac resynchronization therapy (CRT). However, no echocardiographic measure can improve prediction of case selection for CRT. The purpose of this study was to assess the efficacy of a newly combined echocardiographic index for ventricular dyssynchrony and contractility using speckled tracking strain analysis to predict responders to CRT. Forty-seven patients with severe heart failure in New York Heart Association functional class III/IV, left ventricular ejection fraction </=35%, and QRS duration >/=130 ms were included in the study. Echocardiography was performed, and a novel index (i-Index), the product of radial dyssynchrony and radial strain, was calculated. Responder to CRT was defined as a patient with a >/=15% decrease in left ventricular end-systolic volume at 6-month follow-up. Thirty-two patients (68%) were classified as responders. The i-Index was significantly higher in responders than in nonresponders (3,450 +/- 1180 vs 1,481 +/- 841, P <.001). The area under receiver operator characteristic curve was 0.92 for the i-Index, which was better than the index of radial dyssynchrony only (0.74). A cutoff value of i-Index >2,000 predicted responders with 94% sensitivity and 80% specificity. The index using only radial dyssynchrony had 81% sensitivity and 53% specificity. Furthermore, i-Index decreased in responders (1,985 +/- 1261, P <.001) but not in nonresponders (1,684 +/- 866, P = .48). Our findings suggest that a novel combined index by radial strain echocardiography might be a predictor of response to CRT. The value of this novel echocardiographic index requires further assessment in larger studies.
    Heart rhythm: the official journal of the Heart Rhythm Society 05/2010; 7(5):655-61. · 4.56 Impact Factor
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    Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/2010; 55(10).
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    ABSTRACT: Identification of arrhythmogenic pulmonary veins (PVs) initiating atrial fibrillation is helpful for catheter ablation. The aim of this study was to examine the possibility to recognize the arrhythmogenic PV using Holter ECG. In 20 patients, P-wave characteristics were studied during pacing from four PVs. Holter ECG was recorded using two leads: the modified CC5 (Lead 1) and NASA (Lead 2), and the P-wave amplitude and duration were evaluated. In Lead 1, P-waves produced by left PV pacing were significantly lower in amplitude than right PV pacing (-3 +/- 75 vs. 86 +/- 43 microV, P < 0.001). In Lead 2, pacing in superior PVs produced P-waves with higher amplitude than inferior PVs (210 +/- 74 vs. 125 +/- 66 muV, P < 0.001). The criteria proposed by the morphological characteristics of P-waves identified putative arrhythmogenic PVs with an accuracy of 78%. It might be possible to identify putative arrhythmogenic PVs by modified Holter ECG recording.
    Europace 11/2009; 12(1):124-9. · 2.77 Impact Factor
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    ABSTRACT: The relationship between vagal modification and paroxysmal atrial fibrillation (PAF) recurrence after segmental pulmonary vein (PV) isolation (S-PVI) was investigated. S-PVI was performed in 77 PAF patients using a multielectrode basket or circular catheter to achieve electrical disconnection of all 4 PVs independent of eliminating vagal reflexes. Serial Holter-recordings were obtained at baseline, immediately and 1, 3, 6, and 12 months after S-PVI to analyze the heart rate variability. Fifty-one patients were free from symptomatic PAF (Group A) and 26 had late PAF recurrences (Group B) at 12-month follow-up. Immediately after S-PVI, the root mean square of the successive differences (rMSSD) and high-frequency (HF) power, which reflected parasympathetic nervous activity, were significantly lower in Group A than in Group B (rMSSD: 33.6+/-26.0 vs 60.6+/-23.2 ms, P<0.05; ln HF: 8.73+/-0.84 vs 9.31+/-0.95 ms2, P<0.05). There were no significant differences in the average heart rate or ratio of the low-frequency to HF powers between the 2 groups. By multivariate analysis, only the HF immediately after S-PVI was an independent predictor of PAF recurrence (hazard ratio 1.707, 95% confidence interval 1.057-2.756, P<0.05). Vagal modification after S-PVI could also help prevent late recurrence of PAF.
    Circulation Journal 03/2009; 73(4):632-8. · 3.58 Impact Factor
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    ABSTRACT: The atrial fibrillation (AF) recurrence rate after pulmonary vein isolation (PVI) has been relatively high and in some unsuccessful PVI cases, antiarrhythmic drugs that were ineffective before PVI may become effective (hybrid therapy). The purpose of this study was to investigate the relationship between the brain natriuretic peptide (BNP) level and the effect of the hybrid therapy. In 28 lone AF patients undergoing hybrid therapy, the plasma BNP level was measured before PVI and before and 3 months after administering an antiarrhythmic drug. Fifteen patients were free of AF after the hybrid therapy (effective group), and 13 still had recurrent AF after (noneffective group). At baseline, in all patients the BNP level was elevated, and there were no significant differences in the BNP level between the 2 groups. The BNP level was significantly decreased after PVI in the effective group (56.8 +/- 23.1 versus 37.5 +/- 16.7 pg/mL, P < 0.05) but not in the noneffective group (74.3 +/- 47.8 versus 79.7 +/- 54.4 pg/mL, NS). The elevated BNP level normalized in all effective group patients. The criterion consisting of a net value of < 60.0 pg/mL or a reduction in the BNP level of > 10.0 pg/mL after PVI predicted the effective group patients with a high accuracy. A significant reduction in the BNP level after PVI may be a useful predictor of the responders to antiarrhythmic drug therapy in patients with recurrent AF after PVI. The hybrid therapy may be effective in patients whose PVs serve as a dominant AF substrate.
    International Heart Journal 04/2008; 49(2):143-51. · 1.23 Impact Factor
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    ABSTRACT: This study investigated the electrophysiologic characteristics and outcome of superior vena cava (SVC) segmental ostial isolation (SOI) in patients with SVC-initiated paroxysmal atrial fibrillation (PAF). Ninety-five patients with PAF underwent pulmonary vein (PV) SOI using a basket catheter whether the PAF originating from PVs was observed or not. Fifteen of those patients also underwent SVC SOI in the same manner due to evidence of SVC origin PAF. The SVC musculature networks and electrical connections with the atrium (multiple separate electrical connections in 10, multiple separate musculature networks with separate electrical connections in 1, and a continuous broad electrical connection in 4 SVCs) were similar to those of the PV musculature. However, the occurrence of an electrical connection recovery after SOI in patients with recurrent atrial fibrillation was lower for SVCs (25%) than PVs (58%). Superior vena cava SOI appears to have a lower recurrent conduction rate than PV SOI.
    Journal of electrocardiology 11/2007; 40(4):319-25. · 1.08 Impact Factor
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    ABSTRACT: The left atrial appendage (LAA) is one of the major sources of focal atrial tachycardias (ATs). The purpose of this study was to investigate the detailed electrophysiologic characteristics and catheter ablation of focal ATs originating from the LAA. The study population consisted of 47 consecutive patients with 50 focal ATs originating from the left atrium (LA): LAA in 13, left pulmonary veins (PVs) in 14, right PVs in 12, and mitral annulus in 11. Programmed electrical stimulation and pharmacologic testing were performed to examine the mechanism of LAA AT. Left atriography was performed prior to radiofrequency ablation to identify the focus in the LAA. The mechanism of LAA AT was automaticity in 11 and triggered activity in 2. The 13 LAA foci were located mainly at the LAA base: 11 on the medial side and 2 on the lateral side. Atrial activation sequences within the distal coronary sinus were helpful in differentiating these LAA foci. The criterion of a negative P wave in leads I and aVL indicating an LAA AT focus was associated with sensitivity of 92.3%, specificity 97.3%, positive predictive value 92.3%, and negative predictive value 97.3%. No complications occurred in any of the 13 patients. All 13 patients were free of atrial arrhythmias without any antiarrhythmic drugs during follow-up of 8 +/- 3 years. LAA ATs have typical electrophysiologic and electrocardiographic characteristics that are helpful in guiding radiofrequency catheter ablation.
    Heart Rhythm 11/2007; 4(10):1284-91. · 5.05 Impact Factor
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    ABSTRACT: Background:Pulmonary vein (PV) isolation (PVI) has been demonstrated to be an effective technique for curing atrial fibrillation (AF). AF foci that cannot be isolated by PVI (non-PV foci) can become the cause of AF recurrence. The purpose of this study was to investigate the characteristics of non-PV AF foci.Methods and Results:Two hundred consecutive patients with symptomatic AF underwent electrophysiologic studies. In all patients, successful ostial or antral PVI was achieved with a multielectrode basket catheter (MBC). In 45 patients, spontaneous AF was induced even after PVI. In 23 of those patients, 30 AF foci were found in the left atrium (LA) (12 in the PV antrum, and 18 in the LA wall). Twenty-six of those foci were eliminated by focal ablation guided by an MBC. Five of those foci (four in the PV antrum and one in the LA posterior wall) were speculated to be located epicardially because a small potential preceding the LA potential was recorded from the MBC electrodes during AF initiation at the successful ablation site where single large potentials were recorded during sinus rhythm and a longer duration of radiofrequency energy delivery was needed to eliminate them.Conclusions:MBC mapping with induction of spontaneous AF may be useful for identifying non-PV AF foci in the LA after PVI. In some of those non-PV foci, mainly around the PVI lesions, a few electrophysiologic findings suggesting an epicardial location were observed. This may be a rationale for the efficacy of extensive PV ablation
    Pacing and Clinical Electrophysiology 10/2007; 30(11):1323 - 1330. · 1.75 Impact Factor
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    ABSTRACT: The dimensions and electrophysiological characteristics of the antral region of human pulmonary veins (PVs) were investigated. Fifty-five consecutive patients with symptomatic paroxysmal atrial fibrillation underwent PV isolation targeting the PV antrum potentials with a 31 mm multielectrode basket catheter (MBC). The most distal and proximal electrode pairs along the MBC spline where radiofrequency ablation was carried out were identified and the longitudinal distance between those ablation sites (Ld) was measured. When the Ld was > or =6 mm, the PV antrum was defined as noncoaxial. In 56% of the left superior PVs, 42% of the right superior PVs, 63% of the left inferior PVs and 56% of the right inferior PVs, a noncoaxial PV antrum was identified. In each PV, the radiofrequency ablation delivery duration and energy to complete the PV antrum isolation were significantly larger in the PVs with a noncoaxial PV antrum than in those with a coaxial PV antrum. The PV antrum is noncoaxial to the PV in >50% of the PVs, a feature that may increase the complexity of the circumferential isolation technique.
    Circulation Journal 09/2007; 71(9):1430-6. · 3.58 Impact Factor
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    ABSTRACT: Mapping of premature ventricular contractions (PVCs) originating from the right ventricular outflow tract (RVOT) sometimes is not easy because of an unstable incidence and multiple foci of the PVCs. The aim of this study was to evaluate the effectiveness of electroanatomic mapping in catheter ablation of those PVCs. One hundred patients with 134 RVOT origin PVCs were randomly allotted to undergo either conventional (group I; 50 patients with 65 PVCs) or electroanatomic mapping (group II; 50 patients with 69 PVCs). In group II, electroanatomic mapping of the RVOT was performed using auto-freeze maps in patients with frequent PVCs, and pace mapping was performed marking the pacing sites on the remap which was made by extracting the anatomic frame out of the baseline map during sinus rhythm in patients with infrequent PVCs. Successful ablation was achieved in 44 (88%) group I patients and 48 (96%) group II patients (p = 0.14). The fluoroscopy and procedure times and those per PVC morphology were all significantly shorter in group II than group I overall (p < 0.0001 for all comparisons), and in each patient group with infrequent PVCs, frequent PVCs or unstable PVCs (p < 0.05-0.0001). The number of RF applications and that per PVC was significantly smaller in group II than group I (5.3 +/- 1.8 vs 6.2 +/- 2.4, and 4.4 +/- 1.2 vs 5.2 +/- 2.1; p < 0.05). The use of electroanatomic mapping may reduce the fluoroscopy and procedure times in the ablation of RVOT PVCs, but there is no evidence that it improves the overall efficacy of the procedure.
    Journal of Interventional Cardiac Electrophysiology 09/2007; 19(3):187-94. · 1.39 Impact Factor
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    ABSTRACT: The purpose of this study was to examine the relationship between the origin and breakout site of idiopathic ventricular tachycardia (VT) or premature ventricular contractions (PVCs) originating from the myocardium around the ventricular outflow tract. The myocardial network around the ventricular outflow tract is not well known. We studied 70 patients with idiopathic VT (n = 23) or PVCs (n = 47) with a left bundle branch block and inferior QRS axis morphology. Electroanatomical mapping was performed in both the right ventricular outflow tract (RVOT) and aortic sinus cusp (ASC) during VT or PVCs. The earliest ventricular activation (EVA) was recorded in the RVOT in 55 patients (group R) and in the ASC in 15 (group A). In all group R patients, the closest pace map and successful ablation were achieved at the EVA site. Although a successful ablation was achieved at the EVA site in all group A patients, the closest pace map was obtained at the EVA site in 8 and RVOT in 7 (with an excellent pace map in 4). The stimulus to QRS interval was 0 ms during pacing from the RVOT and 36 +/- 8 ms from the ASC. The distance between the EVA and perfect pace map sites in those 4 patients was 11.9 +/- 3.0 mm. Ventricular arrhythmias originating from the ASC often show preferential conduction to the RVOT, which may render pace mapping or some algorithms using the electrocardiographic characteristics less reliable. In some of those cases, an insulated myocardial fiber across the ventricular outflow septum may exist.
    Journal of the American College of Cardiology 09/2007; 50(9):884-91. · 14.09 Impact Factor

Publication Stats

1k Citations
412.55 Total Impact Points

Institutions

  • 2007–2011
    • Social Insurance Chukyo Hospital
      Nagoya, Aichi, Japan
  • 1991–2010
    • Nagoya University
      • • Division of Cardiology
      • • Division of of Internal Medicine
      Nagoya-shi, Aichi-ken, Japan
  • 2002–2009
    • Nagoya Second Red Cross Hospital
      Nagoya, Aichi, Japan
    • Peptide Institute, Inc.
      Ibaragi, Ōsaka, Japan
  • 2007–2008
    • University of Alabama at Birmingham
      • Department of Medicine
      Birmingham, AL, United States
  • 2004–2005
    • National Cerebral and Cardiovascular Center
      Ōsaka, Ōsaka, Japan
  • 1992–1997
    • The University of Tokyo
      • Department of Biological Sciences
      Edo, Tōkyō, Japan
  • 1992–1996
    • Fujita Health University
      • Institute for Comprehensive Medical Science (ICMS)
      Nagoya, Aichi, Japan