Satoshi Nagase

Okayama University, Okayama, Okayama, Japan

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Publications (79)361.6 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Objectives This study aimed to determine the usefulness of the combination of several electrocardiographic (ECG) markers on risk assessment of ventricular fibrillation (VF) in patients with Brugada syndrome (BrS). Background Detection of high/low-risk BrS patients using a noninvasive method is an important issue in the clinical setting. Several ECG markers related to depolarization and repolarization abnormalities have been reported, but the relationship and usefulness of these parameters in VF events are unclear. Methods Baseline characteristics of 246 consecutive patients (236 males; mean age, 47.6±13.6 years) with Brugada type ECG, including 13 patients with a history of VF and 40 patients with a history of syncopal episodes, were retrospectively analyzed. During the mean follow-up period of 45.1 months, VF in 23 patients and sudden cardiac death (SCD) in one patient were observed. Clinical/genetic and electrocardiographic parameters were compared with VF/SCD events. Results By univariate analysis, history of VF, history of syncopal episodes, paroxysmal atrial fibrillation , spontaneous type 1 pattern in the precordial leads, ECG markers of depolarization abnormalities (PQ >200 ms, QRS duration ≥120 ms, and fragmented QRS [f-QRS]), and those of repolarization abnormalities (infero-lateral early repolarization [ER] pattern and QT prolongation) were associated with later cardiac events. By multivariable analysis, history of VF, history of syncopal episodes, infero-lateral ER pattern, f-QRS were independent predictors of documented VF and SCD (odds ratio, 19.61, 28.57, 2.87, and 5.21, respectively, P<0.05). Kaplan-Meier curves showed that the presence/absence of infero-lateral ER and f-QRS provided a worse/better prognosis (log-rank test, P<0.01). Conclusions The combination of depolarization and repolarization abnormalities in BrS is associated with later VF events. The combination of these abnormalities is useful for detecting high- and low-risk BrS patients.
    Journal of the American College of Cardiology 01/2014; · 14.09 Impact Factor
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    Satoshi Nagase
    Journal of Cardiology 01/2014; · 2.30 Impact Factor
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    ABSTRACT: In several cases with idiopathic ventricular fibrillation (VF), VF was initiated by premature ventricular contractions (PVCs) from the Purkinje system. However, the precise characteristics of the Purkinje activity in patients with idiopathic VF remain unclear. We performed an electrophysiological study in a patient with idiopathic VF and examined the correlation between the Purkinje potential and the incidence of PVCs/polymorphic ventricular tachycardia (PMVT). In this case of idiopathic VF, the Purkinje activity caused multiform PVCs and PMVT. The The Purkinje activity and slow conduction of Purkinje fibers are associated with the occurrence of multiform PVCs and PMVT.
    Internal Medicine 01/2014; 53(7):725-8. · 0.97 Impact Factor
  • Satoshi Nagase, Kengo F Kusano
    Circulation Journal 12/2013; · 3.58 Impact Factor
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    ABSTRACT: We report the first case of idiopathic ventricular fibrillation (VF) with inferior and lateral early repolarization (ER) in which left ventricular (LV) epicardial electrogram recording was performed. The patient was a 42-year-old male with inferior and lateral ER on ECG and an episode of VF. In electrophysiological study, we recorded prominent J waves and potentials after the QRS complex at the epicardium of lateral LV, but not within the endocardium at the opposite area. These features were accentuated on pilsicainide administration but diminished on constant atrial pacing and isoproterenol administration. The epicardial J wave almost coincided with the ER on ECG. Atrial pacing and isoproterenol diminished ER; however, pilsicainide also diminished ER with accentuated S wave in lead V4. This might be due to the transmural or far-field conduction delay causing the J wave to merge with the S wave. VF was induced with programmed stimulation only from lateral LV epicardium. The epicardial myocardium of the LV might contribute to arrhythmogenesis in this patient.
    Heart rhythm: the official journal of the Heart Rhythm Society 10/2013; · 4.56 Impact Factor
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    ABSTRACT: BACKGROUNDS: Aim of this study was to investigate the prevalence and the prognostic significance of early repolarization (ER) in infero-lateral leads in patients with Brugada syndrome (BrS) and documented ventricular fibrillation (VF). METHODS AND RESULTS: We investigated 10 different twelve-lead electrocardiograms (ECGs) recorded on different days for each patient to identify the presence of ER, which was defined as J-point elevation of ≥ 0.1 mV in inferior (II, III, aVf) or lateral leads (I, aVL, V4-6) in 49 individuals (46 males, 46±13 years) with a type 1 ECG of BrS and previous history of VF. The ER was observed persistently (in all ECGs) in 15 patients (31%, P group), intermittently (at least one, but not in all ECGs) in 16 patients (33%, I group), and not observed in 18 patients (37%, N group), yielding an overall ER incidence of 63% (31/49). During follow up period (7.7 years), recurrence of VF was documented in all 15 patients (100%) with P group, and less in 12 patients (75%) with I group and in 8 patients (44%) with N group. In Kaplan-Meier analysis, P group showed a worse prognosis than N group. (p=0.0001) Either persistent or intermittent ER in infero-lateral lead was an independent predictor of fatal arrhythmic events (Hazard Ratio, 4.88; 95% CI, 2.02 to 12.7, p=0.0004, 2.50; 95%CI, 1.03-6.43, p=0.043, respectively). CONCLUSIONS: The prevalence of ER in infero-lateral leads was high, and especially persistent form of ER was associated with a worse outcome in BrS patients with documented VF.
    Heart rhythm: the official journal of the Heart Rhythm Society 04/2013; · 4.56 Impact Factor
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    ABSTRACT: BACKGROUND: Centrilobular ground-glass opacity (GGO) is one of the characteristic findings in chest high-resolution computed tomography (HRCT) of patients with pulmonary veno-occlusive disease (PVOD) and patients with pulmonary capillary hemangiomatosis (PCH). However, clinical differential diagnosis of these two diseases is difficult and has not been established. In order to clarify their differences, we compared the sizes of GGOs in chest HRCT and the sizes of capillary assemblies in pulmonary vascular casts between patients diagnosed pathologically with PVOD and PCH. METHODS: We evaluated chest HRCT images for four patients with idiopathic pulmonary arterial hypertension (IPAH), three patients with PVOD and three patients with PCH, and we evaluated pulmonary vascular casts of lung tissues obtained from those patients at lung transplantation or autopsy. RESULTS: Centrilobular GGOs in chest HRCT were observed in patients with PVOD and patients with PCH but not in patients with IPAH. We measured the longest diameter of the GGOs. The size of centrilobular GGOs was significantly larger in patients with PCH than in patients with PVOD (5.60±1.43 mm versus 2.51±0.79 mm, P<.01). We succeeded in visualization of the 3-dimensional structures of pulmonary capillary vessels obtained from the same patients with PVOD and PCH undergoing lung transplantation or autopsy and measured the diameters of capillary assemblies. The longest diameter of capillary assemblies was also significantly larger in patients with PCH than in patients with PVOD (5.44±1.71 mm versus 3.07±1.07 mm, P<.01). CONCLUSION: Measurement of the sizes of centrilobular GGOs in HRCT is a simple and useful method for clinical differential diagnosis of PVOD and PCH.
    Cardiovascular pathology: the official journal of the Society for Cardiovascular Pathology 01/2013; · 1.63 Impact Factor
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    ABSTRACT: Acute vasoreactivity testing for patients with pulmonary arterial hypertension (PAH) has been reported to be useful to identify patients with sustained beneficial response to oral calcium-channel blockers (CCBs), but there is a risk of exacerbation during the testing with oral CCBs. Therefore, we developed a testing method utilizing intravenous nicardipine, a short-acting CCB, and examined the safety and usefulness of acute vasoreactivity testing with nicardipine in PAH patients. Acute vasoreactivity testing with nicardipine was performed in 65 PAH patients. Nicardipine was administered by short-time continuous infusion (1 μg·kg(-1)·min(-1) for 5 min and 2 μg·kg(-1)·min(-1) for 5 min) followed by bolus injection (5 μg/kg). Hemodynamic responses were continuously measured using a right heart catheter. Acute responders were defined as patients who showed a decrease in mean pulmonary artery pressure of at least 10 mmHg to an absolute level below 40 mmHg with preserved or increased cardiac output. Two acute responders and sixty-three non-acute responders were identified. There was no hemodynamic instability requiring additional inotropic agents or death during the testing. Acute responders had good responses to long-term oral CCBs. The acute vasoreactivity testing with nicardipine might be safe and useful for identifying CCB responders in PAH patients.
    Journal of Pharmacological Sciences 10/2012; · 2.15 Impact Factor
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    ABSTRACT: Background- We investigated the acute effects of implantable cardioverter-defibrillator shock on myocardium, cardiac function, and hemodynamics in relation to left ventricular systolic function. Methods and Results- We studied 50 patients who underwent implantable cardioverter-defibrillator implantation and defibrillation threshold (DFT) testing: 25 patients with left ventricular ejection fraction (LVEF) ≥45% and 25 patients with LVEF <45%. We measured cardiac biomarkers (creatine kinase, creatine kinase-MB, myoglobin, cardiac troponin T and I, and N-terminal probrain natriuretic peptide). Left ventricular relaxation was assessed by global longitudinal strain rate during the isovolumetric relaxation period using speckle-tracking echocardiography. Blood sampling and echocardiography were performed before, immediately after, and 5 minutes and 4 hours after DFT testing. Mean arterial pressure was measured directly during DFT testing. Cardiac biomarkers showed no significant changes in either group. LVEF was decreased until 5 minutes after DFT testing and had recovered to the baseline at 4 hours in the group with reduced LVEF (P<0.001), whereas LVEF reduction was not observed in the group with preserved LVEF (P=0.637). Global isovolumetric relaxation period was decreased until 5 minutes after DFT testing and had recovered to the baseline at 4 hours in both groups (preserved LVEF: 0.39±0.14 versus 0.23±0.13* versus 0.23±0.13* versus 0.40±0.13 s(-1), *P<0.001 versus baseline; reduced LVEF: 0.15±0.05 versus 0.08±0.04† versus 0.09±0.04† versus 0.15±0.05 s(-1), †P<0.001 versus baseline, repeated-measures ANOVA). Time to recovery of mean arterial pressure to the baseline was prolonged in the group with reduced LVEF (P<0.001). Conclusions- Implantable cardioverter-defibrillator shock transiently impairs cardiac function and hemodynamics especially in patients with systolic dysfunction, although significant tissue injury is not observed.
    Circulation Arrhythmia and Electrophysiology 07/2012; 5(5):898-905. · 5.95 Impact Factor
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    ABSTRACT: Syncope in patients with Brugada syndrome is usually associated with ventricular tachyarrhythmia, but some episodes of syncope can be related to autonomic disorders. The purpose of this study was to investigate the characteristics of syncope to differentiate high-risk syncope episodes from low-risk events in patients with Brugada syndrome. We studied 84 patients with type 1 electrocardiogram and syncope. Patients were divided into 2 groups: patients with prodrome (prodromal group; n = 41) and patients without prodrome (nonprodromal group; n = 43). Ventricular fibrillation (VF) was documented at index event in 19 patients: 4 patients (21%) with documented VF experienced a prodrome prior to the onset of VF, whereas 15 patients (79%) did not have symptoms prior to documented VF (P <.01). Twenty-seven patients in the prodromal group and 7 patients in the nonprodromal group were considered to have syncope related to autonomic dysfunction. Syncope in other patients was defined as unexplained syncope. During the follow-up period (48 ± 48 months), recurrent syncope due to VF occurred in 13 patients among patients with only unexplained syncope and was more frequent in the nonprodromal group (n = 10) than in the prodromal group (n = 3; P = .044). In multivariate analysis, blurred vision (hazard ratio [HR] 0.20) and abnormal respiration (HR 2.18) and fragmented QRS (HR 2.39) were independently associated with the occurrence of VF. Syncope with prodrome, especially blurred vision, suggests a benign etiology of syncope in patients with Brugada syndrome.
    Heart rhythm: the official journal of the Heart Rhythm Society 11/2011; 9(5):752-9. · 4.56 Impact Factor
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    ABSTRACT: Intermittent arm ischemia before percutaneous coronary intervention induces remote ischemic preconditioning (RIPC) and attenuates myocardial injury in patients with myocardial infarction. Several studies have shown that intermittent arm ischemia increases coronary flow and is related to autonomic nerve system. The aim of this study was to determine whether intermittent arm ischemia induces vasodilatation of other arteries and to assess changes in the autonomic nerve system during intermittent arm ischemia in humans. We measured change in the right brachial artery diameter during intermittent left arm ischemia through three cycles of 5-min inflation (200 mmHg) and 5-min deflation of a blood-pressure cuff using a 10-MHz linear array transducer probe in 20 healthy volunteers. We simultaneously performed power spectral analysis of heart rate. Ischemia-reperfusion of the left arm significantly dilated the right brachial artery time-dependently, resulting in a 3.2 ± 0.4% increase after the 3rd cycle. In the power spectral analysis of heart rate, the high-frequency domain (HF), which is a marker of parasympathetic activity, was significantly higher after the 3rd cycle of ischemia-reperfusion than baseline HF (P = 0.02). Intermittent arm ischemia was accompanied by vasodilatation of another artery and enhancement of parasympathetic activity. Those effects may play an important role in the mechanism of RIPC.
    The Journal of Physiological Sciences 09/2011; 61(6):507-13. · 1.09 Impact Factor
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    ABSTRACT: Remodeling of the pulmonary artery by an inappropriate increase of pulmonary artery smooth muscle cells (PASMCs) is problematic in the treatment of idiopathic pulmonary arterial hypertension (IPAH). Effective treatment that achieves reverse remodeling is required. The aim of this study was to assess the pro-apoptotic effects of imatinib, a platelet-derived growth factor (PDGF)-receptor tyrosine kinase inhibitor, on PASMCs obtained from patients with IPAH. PASMCs were obtained from 8 patients with IPAH undergoing lung transplantation. Cellular proliferation was assessed by (3)H-thymidine incorporation. Pro-apoptotic effects of imatinib were examined using TUNEL and caspase-3,7 assays and using transmission electron microscopy. Treatment with imatinib (0.1 to 10 μg/mL) significantly inhibited PDGF-BB (10 ng/mL)-induced proliferation of PASMCs from IPAH patients. Imatinib (1 μg/mL) did not induce apoptosis in quiescent IPAH-PASMCs, but it had a pro-apoptotic effect on IPAH-PASMCs stimulated with PDGF-BB. Imatinib did not induce apoptosis in normal control PASMCs with or without PDGF-BB stimulation. PDGF-BB induced phosphorylation of Akt at 15 min, and Akt phosphorylation was inhibited by imatinib in IPAH-PASMCs. Akt-I-1/2 (1 μmol/L), an Akt inhibitor, in the presence of PDGF-BB significantly increased apoptotic cells compared with the control condition. Thus, Akt-I-1/2 could mimic the effects of imatinib on PASMCs. Imatinib has anti-proliferative and pro-apoptotic effects on IPAH-PASMCs stimulated with PDGF. The inhibitory effect of imatinib on Akt phosphorylation induced by PDGF plays an important role in the pro-apoptotic effect.
    International journal of cardiology 03/2011; 159(2):100-6. · 6.18 Impact Factor
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    ABSTRACT: Patients with Brugada syndrome (BS) often have spontaneous changes in their electrocardiogram (ECG). To evaluate the significance of ECG alterations, we investigated the relationships between the ECG and the occurrence of ventricular fibrillation (VF) in both patients and an experimental model of BS. In study 1, we evaluated ECG alterations in BS patients with (VF+, n = 33) and without (VF-, n = 41) spontaneous VF. We defined type 0 ECG as coved-type ST elevation without a negative T wave, which represents the existence of loss-of-dome (LOD) type action potentials (APs). In study 2, we optically mapped epicardial APs and recorded transmural ECGs in 34 canine right ventricular tissues with a drug-induced BS model by a combination of pinacidil and pilsicainide. In study 1, changes in ST level ≥0.2 mV were more frequent in the VF+ group than in the VF- group (P <.01). Spontaneous ECG alterations and appearances of types 1 and 0 ECGs were more frequent in the VF+ group than in the VF- group (P <.01). In study 2, BS model with spike-and-dome (SAD) epicardial APs exhibited type 1 ECG. Deepening of the phase 1 notch of the APs induced heterogeneous conversion of the APs (SAD→LOD) and resulted in ECG conversion from type 1 to type 0. Significant AP heterogeneity often appeared during AP alterations and initiated phase 2 reentry. Tissues having ventricular tachycardia (VT; n = 20) had more frequent alterations in APs and ECG than in tissues without VT (n = 14; P <.01). ECG alterations, especially conversion between types 0 and 1, are associated with significant AP heterogeneity that can initiate VF in BS.
    Heart rhythm: the official journal of the Heart Rhythm Society 02/2011; 8(7):1014-21. · 4.56 Impact Factor
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    ABSTRACT: It is estimated that approximately half of the deaths in patients with HF are sudden and that the most likely causes of sudden death are lethal ventricular tachyarrhythmias such as ventricular tachycardia (VT) or fibrillation (VF). However, the precise mechanism of ventricular tachyarrhythmias remains unknown. The KCNH2 channel conducting the delayed rectifier K(+) current (I(Kr)) is recognized as the most susceptible channel in acquired long QT syndrome. Recent findings have revealed that not only suppression but also enhancement of I(Kr) increase vulnerability to major arrhythmic events, as seen in short QT syndrome. Therefore, we investigated the existence of a circulating KCNH2 current-modifying factor in patients with HF. We examined the effects of serum of HF patients on recombinant I(Kr) recorded from HEK 293 cells stably expressing KCNH2 by using the whole-cell patch-clamp technique. Study subjects were 14 patients with non-ischemic HF and 6 normal controls. Seven patients had a history of documented ventricular tachyarrhythmias (VT: 7 and VF: 1). Overnight treatment with 2% serum obtained from HF patients with ventricular arrhythmia resulted in a significant enhancement in the peaks of I(Kr) tail currents compared to the serum from normal controls and HF patients without ventricular arrhythmia. Here we provide the first evidence for the presence of a circulating KCNH2 channel activator in patients with HF and ventricular tachyarrhythmias. This factor may be responsible for arhythmogenesis in patients with HF.
    PLoS ONE 01/2011; 6(5):e19897. · 3.53 Impact Factor
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/2011; 57(14).
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/2011; 57(14).
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/2011; 57(14).
  • Journal of the American College of Cardiology 12/2010; 56(25):2143-5. · 14.09 Impact Factor
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    ABSTRACT: A 45-year-old man with dilated cardiomyopathy was admitted to our hospital due to congestive heart failure (CHF). Despite the optimal medical treatment, his condition had not improved because of severe left ventricular dysfunction. Because he experienced non-sustained ventricular tachycardia (VT), a biventricular implantable cardioverter-defibrillator (Bi-V ICD) was implanted for reduction of dyssynchrony and primary prevention of lethal tachyarrhythmia. After discharge, he developed CHF and was transported to our hospital by ambulance. In the ambulance, monomorphic sustained VT with 200 bpm suddenly occurred. The ICD detected it as fast VT and anti-tachycardia pacing (ATP) was delivered. After the ATP therapy, RR intervals of VT became irregular and prolonged. Ventricular fibrillation-like electrical activity was recorded by a far-field electrogram from the defibrillator, but the tachycardia cycle length exceeded 400 ms which is under the tachycardia detection rate. The device failed to deliver a shock and the patient had to be rescued with an external shock. This is a rare case of fast VT that degenerated into undetectable life-threatening tachyarrhythmia by ATP.
    Journal of Cardiology Cases 12/2010; 2(3):e159–e162.
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    ABSTRACT: Acquired long QT syndrome (LQTS) is a disease due to a secondary repolarization abnormality induced by various predisposing factors. In contrast to congenital LQTS, risk factors that produce acquired LQTS include organic heart diseases that often exhibit depolarization abnormality. Although various repolarization parameters have been evaluated in acquired LQTS, the existence of depolarization abnormality in association with torsades de pointes (TdP) has not been reported. The purpose of this study was to evaluate both repolarization (QT components) and depolarization parameters (fragmented QRS [fQRS]) in acquired LQTS patients with markedly prolonged QT interval. Seventy patients with acquired severe QT prolongation (QTc ≥ 550 ms) were studied. Thirty-two patients had syncope or TdP (syncope group). Thirty-eight patients did not have any symptoms (asymptomatic group). The existence of fQRS and QT components (QT, QTc, Tpe [interval between peak and end of T wave] intervals, and U-wave voltage) was analyzed. The syncope group had more frequent fQRS (81%) than did the asymptomatic group (21%, P < .01) and the incidence of fQRS was not different before and after removal of predisposing factors. The incidence of organic heart disease was not different between the two groups. No differences in QTc interval were noted between the syncope and asymptomatic groups, although the syncope group had longer QT and Tpe intervals and higher U wave than the asymptomatic group (P < .01). Acquired predisposing factors promoted repolarization abnormality (especially prolongation of QT and Tpe intervals), and the existence of fQRS had an important role in the development of TdP in patients with acquired LQTS.
    Heart rhythm: the official journal of the Heart Rhythm Society 12/2010; 7(12):1808-14. · 4.56 Impact Factor

Publication Stats

1k Citations
361.60 Total Impact Points

Institutions

  • 2002–2012
    • Okayama University
      • Department of Cardiovascular Medicine
      Okayama, Okayama, Japan
  • 2006
    • The University of Tokyo
      • Department of Cardiovascular Medicine
      Tokyo, Tokyo-to, Japan