Nishiyama, Takahiko



School of Medicine, Endowed Research Laboratory for Arrhythmia Advanced Therapeutics (Shinanomachi)


Project Senior Assistant Professor (Non-tenured)/Project Assistant Professor (Non-tenured)/Project Lecturer (Non-tenured)

Career 【 Display / hide

  • 2005.04

    Keio University School of Medicine

Academic Background 【 Display / hide

  • 1999.04

    Keio University School of Medicine


  • 2008.04

    Keio University Graduate School of Medicine

    Graduate School, Graduated, Doctoral course

Academic Degrees 【 Display / hide

  • 博士, 慶應義塾大学医学部


Papers 【 Display / hide

  • Effect of Compliance to Updated AHA/ACC Performance and Quality Measures Among Patients With Atrial Fibrillation on Outcome (from Japanese Multicenter Registry)

    Inohara, T., Kimura, T., Ueda, I., Ikemura, N., Tanimoto, K., Nishiyama, N., Aizawa, Y., Nishiyama, T., Katsumata, Y., Fukuda, K., Takatsuki, S. and Kohsaka, S.

    Am J Cardiol 120 ( 4 ) 595 - 600 2017.08

    ISSN  0002-9149

     View Summary

    Performance measures (PMs) are used to accelerate translation of scientific evidence into clinical practice. However, it remains unknown how they are applied in the real world and whether the compliance to these metrics will lead to improved patient's outcome in atrial fibrillation (AF). Within the Japanese multicenter AF registry (n = 1,874), adherence of the AF PMs (based on 2016 American Heart Association/American College of Cardiology criteria) and its association with quality of life scaling and clinical outcomes was evaluated. The patient was deemed "adherent" when all applicable components of the PMs for outpatient settings (CHA2DS2-VASc risk score documentation [PM-4], anticoagulation prescribed [PM-5], and monthly international normalized ratio (INR) for warfarin treatment [PM-6]) were satisfied. The Atrial Fibrillation Effect on Quality of Life (AFEQT) questionnaire was assessed at baseline and 1 year. About a half of patients (46.1%) were adherent to the AF PMs. PMs were more frequently achieved in patients managed with rhythm control compared with rate control. The achievement rate for each component was 53.9% for PM-4, 85.6% for PM-5, and 90.3% for PM-6, respectively. Although AFEQT global scores at baseline were similar (median 79.2 [interquartile ranges 66.7 to 88.5] vs 77.1 [64.8 to 88.0], p = 0.227), AFEQT global scores at 1-year follow-up were significantly greater in adherence group than those in nonadherence group (89.2 [78.5 to 96.6] vs 86.7 [76.7 to 95.0], p = 0.021). This tendency was consistent regardless of therapeutic strategies. There remains an important opportunity to improve the quality of care in patients with AF. Adherence to the AF PMs might lead to the improvement of patient's quality of life.

  • Mitral isthmus ablation using a circular mapping catheter positioned in the left atrial appendage as a reference for conduction block

    Nishiyama, T., Kimura, T., Fujisawa, T., Nakajima, K., Kunitomi, A., Kashimura, S., Katsumata, Y., Nishiyama, N., Aizawa, Y., Fukuda, K. and Takatsuki, S.

    Oncotarget 8 ( 32 ) 52724 - 52734 2017.08

    ISSN  1949-2553

     View Summary

    BACKGROUND: For perimitral atrial flutter (PMFL) developing after catheter ablation of atrial fibrillation (AF), to create a complete conduction block at the mitral isthmus (MI) is mandatory to terminate it, however, it is still challenging. METHODS: This study consisted of 80 patients (74 male, 61 +/- 8.1 years) undergoing MI ablation. After a circular mapping catheter was positioned at the neck of the left atrial appendage (LAA), the MI ablation was performed on the MI line just below the LAA neck targeting the earliest activation recording site of the LAA catheter during pacing from the coronary sinus (CS). When ablation during CS pacing was not successful, an RF delivery during LAA pacing was applied targeting the earliest activation site just below the MI line. If the endocardial approach failed, an RF application inside the CS was attempted. RESULTS: With the endocardial approach, acute success was achieved in 51/80 patients (64%). Additional epicardial ablation from the CS was performed in 26/29 (90%) endocardially unsuccessful patients and conduction block at the MI was achieved in 21/26 (81%). Overall, complete conduction block at the MI was achieved in 72/80 patients (90%). At a mean follow-up of 16 +/- 6 months, 20 patients (25%) had recurrence of atrial arrhythmias (AT: 12, AF: 8), and 10 (AT: 7, AF : 3) underwent a second procedure in which an LMI block line was completed in 3 (33%). PMFL was diagnosed in 6 out of 7 AT patients. No complications were observed. CONCLUSIONS: Creating linear lesions just beneath the neck of the LAA was highly successful under the guidance of a circular mapping catheter in the LAA using a steerable sheath. An RF application from the CS was needed in less than half of the cases.

  • Discrimination between QRS and T Waves Using a Right Parasternal Lead for S-ICD in a Patient with a Single Ventricle

    Nishiyama, T., Kimura, T., Nishiyama, N., Aizawa, Y., Fukuda, K. and Takatsuki, S.

    Pacing Clin Electrophysiol 40 ( 7 ) 904 - 907 2017.07

    ISSN  0147-8389

     View Summary

    The subcutaneous implantable cardioverter-defibrillator (S-ICD) is a useful option for patients with a single ventricle (SV) in which transvenous leads are contraindicated because of intracardiac shunts. We report a case in which a right parasternal lead placement was indicated for an S-ICD in a resuscitated patient with an SV. There were significant changes in the magnitude of R to T waves ratio in the right compared to the left parasternal lead position. Screening in the right parasternal position is effective for selecting appropriate patients with congenital heart disease for S-ICD implantations.

  • Tachycardia-Induced J-Wave Changes in Patients With and Without Idiopathic Ventricular Fibrillation

    Aizawa, Y., Takatsuki, S., Nishiyama, T., Kimura, T., Kohsaka, S., Kaneko, Y., Inden, Y., Takahashi, N., Nagase, S., Aizawa, Y. and Fukuda, K.

    Circ Arrhythm Electrophysiol 10 ( 7 )  2017.07

    ISSN  1941-3084

     View Summary

    BACKGROUND: To know the underlying mechanisms of J waves, the response to atrial pacing was studied in patients with idiopathic ventricular fibrillation (IVF) and patients with non-IVF. METHODS AND RESULTS: In 8 patients with IVF, the J-wave amplitude was measured before, during, and after atrial pacing. All patients had episodes of ventricular fibrillation without structural heart disease. The responses of J waves were compared with those of the 17 non-IVF control subjects who revealed J waves but no history of cardiac arrest and underwent electrophysiological study. The IVF patients were younger than the non-IVF patients (28+/-10 versus 52+/-14 years, respectively; P=0.002) and had larger J waves with more extensive distribution. J waves decreased from 0.35+/-0.26 to 0.22+/-0.23 mV (P=0.025) when the RR intervals were shortened from 782+/-88 to 573+/-162 ms (P=0.001). A decrease (>/=0.05 mV) in the J-wave amplitude was observed in 6 of the 8 patients. In addition, 1 patient showed a distinct reduction of J waves in the unipolar epicardial leads. In contrast, J waves were augmented in the 17 non-IVF subjects from 0.27+/-0.09 to 0.38+/-0.10 mV (P<0.001): augmented in 9 and unchanged in the 8 subjects. The different response patterns of J waves to rapid pacing suggest different mechanisms: early repolarization in IVF patients and conduction delay in non-IVF patients. CONCLUSIONS: The response to atrial pacing was different between the IVF and non-IVF patients, which suggests the presence of different mechanisms for the genesis of J waves.

  • A subtype of idiopathic ventricular fibrillation and its relevance to catheter ablation and genetic variants

    Nishiyama, T., Aizawa, Y., Ito, S., Katsumata, Y., Kimura, T. and Takatsuki, S.

    HeartRhythm Case Rep 3 ( 5 ) 277 - 281 2017.05

    ISSN  2214-0271

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Papers, etc., Registered in KOARA 【 Display / hide

Research Projects of Competitive Funds, etc. 【 Display / hide

  • 心筋分化における環状RNAの分子メカニズムの解明


    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

  • Long noncoding RNA in cardiac regeneration


    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (B), Principal investigator


Courses Taught 【 Display / hide