Mari Iwamoto

Yokohama City University, Yokohama-shi, Kanagawa-ken, Japan

Are you Mari Iwamoto?

Claim your profile

Publications (22)82.59 Total impact

  • Article: Inhibition of phosphodiesterase type 3 dilates the rat ductus arteriosus without inducing intimal thickening.
    [show abstract] [hide abstract]
    ABSTRACT: Background: Prostaglandin E(1) (PGE(1)), via cAMP, dilates the ductus arteriosus (DA). For patients with DA-dependent congenital heart disease (CHD), PGE(1) is the sole DA dilator that is used until surgery, but PGE(1) has a short duration of action, and frequently induces apnea. Most importantly, PGE(1) increases hyaluronan (HA) production, leading to intimal thickening (IT) and eventually DA stenosis after long-term use. The purpose of this study was therefore to investigate potential DA dilators, such as phosphodiesterase 3 (PDE3) inhibitors, as alternatives to PGE(1). Methods and Results: Expression of PDE3a and PDE3b mRNAs in rat DA tissue was higher than in the pulmonary artery. I.p. milrinone (10 or 1mg/kg) or olprinone (5 or 0.5mg/kg) induced maximal dilatation of the DA lasting for up to 2h in rat neonates. In contrast, vasodilation induced by PGE(1) (10μg/kg) was diminished within 2h. No respiratory distress was observed with milrinone or olprinone. Most important, milrinone did not induce HA production, cell migration, or proliferation when applied to cultured rat DA smooth muscle cells. Further, high expression of both PDE3a and PDE3b was demonstrated in the human DA tissue of CHD patients. Conclusions: Because PDE3 inhibitors induced longer-lasting vasodilation without causing apnea or HA-mediated IT, they may be good alternatives to PGE(1) for patients with DA-dependent CHD.  (Circ J 2012; 76: 2456-2464).
    Circulation Journal 07/2012; 76(10):2456-64. · 3.77 Impact Factor
  • Article: Long-term efficacy of plasma exchange treatment for refractory Kawasaki disease.
    [show abstract] [hide abstract]
    ABSTRACT: The treatment of Kawasaki disease patients who fail to respond to initial i.v. immunoglobulin (IVIG) therapy is controversial. The aim of the present study was to investigate the long-term efficacy of plasma exchange (PE) treatment for refractory Kawasaki disease. A total of 125 Kawasaki disease patients refractory to IVIG were treated with PE. Coronary artery lesions (CAL) before PE, in the acute period, and during the late period were examined retrospectively. Residual sequelae requiring medical treatment occurred in six cases in the late period. The outcomes of treatment tended to be better when PE was begun in the early stage. Sequelae remained in 2.8% of patients in whom PE was initiated prior to day 9 after onset, and were present in 15% of patients in whom PE was started on or after day 10. The 105 patients whose coronary arteries were normal before PE had no sequelae (residual sequelae: 0%). Dilatation was present before PE in 14 patients, but remained in only two patients in the late period (residual sequelae, 14.3%). In four of the six patients in whom aneurysms had already formed before PE, the lesions had advanced into giant aneurysms, but in the other two patients they returned to the normal range (residual sequelae, 66.6%). The outcomes of PE for Kawasaki disease refractory to IVIG are favorable, and the effectiveness of this treatment is excellent, particularly if it is initiated before CAL arise.
    Pediatrics International 02/2012; 54(1):99-103. · 0.63 Impact Factor
  • Article: Intrapericardial and retrocardial implantation of implantable cardioverter-defibrillator lead in a child with type 3 long QT syndrome.
    [show abstract] [hide abstract]
    ABSTRACT: A 6-year-old girl with type 3 long QT syndrome was safely and successfully implanted with an implantable cardioverter-defibrillator (ICD) system. Prior to implantation, she had experienced uncontrollable life-threatening arrhythmia in spite of high-dose administration of mexiletine. An ICD coil lead for transvenous use was placed in the intrapericardial and retrocardial space and was connected to a generator placed in front of the posterior sheath of the right abdominal rectal muscle. Administration of a beta-blocker in addition to atrial pacing almost completely eliminated the patient's life-threatening arrhythmia attacks. Intrapericardial and retrocardial implantation of ICD coil leads might be useful for children.
    Pediatric Cardiology 08/2011; 32(7):1048-52. · 1.30 Impact Factor
  • Article: Detection of extra components of T wave by independent component analysis in congenital long-QT syndrome.
    [show abstract] [hide abstract]
    ABSTRACT: The main ECG criteria for the diagnosis of long-QT syndrome (LQTS) include abnormal T-wave morphology as well as prolonged QT interval. The T wave in LQTS probably includes additional components of the myocardial repolarization process, which are derived from aberrant ion currents. We investigated whether independent component analysis (ICA) can extract such abnormal repolarization components. Digital ECG data were obtained as a time series from 10 channels using 20 surface electrodes in 22 patients with genetically confirmed LQTS type 1 (LQT1) and 30 normal subjects. In each case, T-wave area was analyzed by radical ICA after noise reduction by the wavelet thresholding method. Furthermore, inverse ICA was applied to determine the origin of each independent component (IC). Radical ICA revealed that a T-wave consisted of 4 basic ICs in all control subjects, whereas ≥ 5 (mostly 6) ICs were identified in all 22 patients with LQT1. The extra ICs, which were not evident in normal subjects, were assumed to contribute to the formation of abnormal T-wave morphology. The extra ICs were identified even in patients with normal QTc values and in those taking β-blockers. Inverse ICA indicated that the additional ICs originate predominantly from the late phase of the T wave of the left ventricle. Extra ICs appear during repolarization in all patients with LQT1 but not in normal subjects. ICA is a potentially useful multivariate statistical method to differentiate patients with LQT1 from normal subjects.
    Circulation Arrhythmia and Electrophysiology 04/2011; 4(4):456-64. · 6.46 Impact Factor
  • Article: Idiopathic ventricular tachycardia in children.
    Mari Iwamoto
    Circulation Journal 02/2011; 75(3):544-5. · 3.77 Impact Factor
  • Article: Calcium-alkali syndrome-like symptoms manifested by daily alphacalcidol and thiazide.
    [show abstract] [hide abstract]
    ABSTRACT: A 73-year-old man was admitted with complaints of a 2-month history of generalized weakness and numbness. Laboratory examination revealed hypercalcemia, metabolic alkalosis, and kidney injury, similar to the traditional milk-alkali syndrome. The clinical history and the response to therapy indicated that alphacalcidol and thiazide taken daily were the cause. Recently, it has been recommended the term "milk-alkali syndrome" be replaced by "calcium-alkali syndrome", which broadens the definition of the condition. This case suggests that the calcium-alkali syndrome can occur without calcium and alkali, but rather with alphacalcidol and a thiazide diuretic.
    Internal Medicine 01/2010; 49(9):837-40. · 0.94 Impact Factor
  • Article: Clinical characteristics and genetic background of congenital long-QT syndrome diagnosed in fetal, neonatal, and infantile life: a nationwide questionnaire survey in Japan.
    [show abstract] [hide abstract]
    ABSTRACT: Data on the clinical presentation and genotype-phenotype correlation of patients with congenital long-QT syndrome (LQTS) diagnosed at perinatal through infantile period are limited. A nationwide survey was conducted to characterize how LQTS detected during those periods is different from that in childhood or adolescence. Using questionnaires, 58 cases were registered from 33 institutions. Diagnosis (or suspicion) of LQTS was made during fetal life (n=18), the neonatal period (n=31, 18 of them at 0 to 2 days of life), and beyond the neonatal period (n=9). Clinical presentation of LQTS included sinus bradycardia (n=37), ventricular tachycardia/torsades de pointes (n=27), atrioventricular block (n=23), family history of LQTS (n=21), sudden cardiac death/aborted cardiac arrest (n=14), convulsion (n=5), syncope (n=5), and others. Genetic testing was available in 41 (71%) cases, and the genotype was confirmed in 29 (71%) cases, consisting of LQT1 (n=11), LQT2 (n=11), LQT3 (n=6), and LQT8 (n=1). Ventricular tachycardia/torsades de pointes and atrioventricular block were almost exclusively observed in patients with LQT2, LQT3, and LQT8, as well as in those with no known mutation. In LQT1 patients, clues to diagnosis were mostly sinus bradycardia or family history of LQTS. Sudden cardiac death/aborted cardiac arrest (n=14) was noted in 4 cases with no known mutations as well as in 4 genotyped cases, although the remaining 6 did not undergo genotyping. Their subsequent clinical course after aborted cardiac arrest was favorable with administration of beta-blockers and mexiletine and with pacemaker implantation/implantable cardioverter-defibrillator. Patients with LQTS who showed life-threatening arrhythmias at perinatal periods were mostly those with LQT2, LQT3, or no known mutations. Independent of the genotype, aggressive intervention resulted in effective suppression of arrhythmias, with only 7 deaths recorded.
    Circulation Arrhythmia and Electrophysiology 12/2009; 3(1):10-7. · 6.46 Impact Factor
  • Article: T-type Ca2+ channels promote oxygenation-induced closure of the rat ductus arteriosus not only by vasoconstriction but also by neointima formation.
    [show abstract] [hide abstract]
    ABSTRACT: The ductus arteriosus (DA), an essential vascular shunt for fetal circulation, begins to close immediately after birth. Although Ca(2+) influx through several membrane Ca(2+) channels is known to regulate vasoconstriction of the DA, the role of the T-type voltage-dependent Ca(2+) channel (VDCC) in DA closure remains unclear. Here we found that the expression of alpha1G, a T-type isoform that is known to exhibit a tissue-restricted expression pattern in the rat neonatal DA, was significantly up-regulated in oxygenated rat DA tissues and smooth muscle cells (SMCs). Immunohistological analysis revealed that alpha1G was localized predominantly in the central core of neonatal DA at birth. DA SMC migration was significantly increased by alpha1G overexpression. Moreover, it was decreased by adding alpha1G-specific small interfering RNAs or using R(-)-efonidipine, a highly selective T-type VDCC blocker. Furthermore, an oxygenation-mediated increase in an intracellular Ca(2+) concentration of DA SMCs was significantly decreased by adding alpha1G-specific siRNAs or using R(-)-efonidipine. Although a prostaglandin E receptor EP4 agonist potently promoted intimal thickening of the DA explants, R(-)-efonidipine (10(-6) m) significantly inhibited EP4-promoted intimal thickening by 40% using DA tissues at preterm in organ culture. Moreover, R(-)-efonidipine (10(-6) m) significantly attenuated oxygenation-induced vasoconstriction by approximately 27% using a vascular ring of fetal DA at term. Finally, R(-)-efonidipine significantly delayed the closure of in vivo DA in neonatal rats. These results indicate that T-type VDCC, especially alpha1G, which is predominantly expressed in neonatal DA, plays a unique role in DA closure, implying that T-type VDCC is an alternative therapeutic target to regulate the patency of DA.
    Journal of Biological Chemistry 07/2009; 284(36):24025-34. · 4.77 Impact Factor
  • Article: Catheter-related bacteremia caused by Agrobacterium radiobacter in a hemodialysis patient.
    [show abstract] [hide abstract]
    ABSTRACT: Agrobacterium radiobacter, a Gram-negative bacillus, is recognized as an emerging opportunistic human pathogen that has a propensity to cause infections in patients with indwelling foreign devices. Here, we describe the first reported case of catheter-related bacteremia caused by A. radiobacter in a hemodialysis patient with a long-term tunneled-cuffed hemodialysis catheter. This case shows that A. radiobacter should be included in the list of pathogens that can cause catheter-related bacteremia in hemodialysis patients.
    Internal Medicine 02/2009; 48(6):455-7. · 0.94 Impact Factor
  • Article: Calcium-alkali syndrome due to vitamin D administration and magnesium oxide administration.
    American Journal of Kidney Diseases 02/2009; 53(4):711-4. · 5.43 Impact Factor
  • Article: [Case of Henoch-Schönlein purpura nephritis successfully treated with tonsillectomy and steroid pulse therapy].
    [show abstract] [hide abstract]
    ABSTRACT: A 30-year-old Japanese man was admitted to our hospital because of fever, sore throat, abdominal pain, purpura skin lesion of the lower legs, and macrohematuria. On admission, his urine was positive (++) for protein; the sediment contained 100 red blood cells per high-power field, and the daily proteinuria level was 1.7 g. Renal biopsy was performed, and we diagnosed Henoch-Schönlein purpura nephritis (HSPN). Six months after the renal biopsy, the patient underwent a tonsillectomy. The pathological diagnosis of the resected tonsils was chronic tonsillitis. After tonsillectomy, the daily proteinuria had decreased to 0.1 g and the sediment contained only 10-19 red blood cells per high-power field. High-dose methylprednisolone therapy (500 mg/day for 3 days for three courses) was started two weeks after the tonsillectomy, followed by oral prednisolone at the initial dose of 30 mg on alternate days. The oral prednisolone was tapered gradually over 1 year. Antiplatelet drug (dipyridamole, 300 mg/day) and angiotensin II receptor antagonist (olmesartan, 10 mg/day) were also administered. This combination therapy resulted in a significant decrease in proteinuria and disappearance of microhematuria. The patient finally achieved clinical remission. Recent reports have shown that in patients with IgA nephropathy, combined tonsillectomy and methylprednisolone pulse therapy have an effect on clinical remission. In addition, it has been suggested that HSPN and IgA nephropathy represent a spectrum of clinical presentations of similar disorders. The result of this case indicated that this combination therapy had a favorable effect on clinical remission in adult patients with HSPN.
    Nippon Jinzo Gakkai shi 02/2009; 51(4):484-9.
  • Article: Long-term electrocardiographic follow-up from childhood of an adult patient with Brugada syndrome associated with sick sinus syndrome.
    [show abstract] [hide abstract]
    ABSTRACT: We had the unique opportunity of following the electrocardiographic (ECG) course of a 13-year-old male with sinus dysfunction and atrial flutter who subsequently developed a Brugada-type ECG pattern associated with sick sinus syndrome at 25 years old. Family history showed that the patient's mother and maternal grandfather suddenly died while sleeping at night. When the patient was 13 years old, he lost consciousness after running a marathon. The patient was diagnosed with sinus dysfunction and atrial flutter, and he underwent pacemaker implantation at 15 years old. ECG examinations performed between 13 and 20 years old showed incomplete right bundle branch block and ST elevation with early depolarization. On ECG examinations performed when the patient was 21 years old and thereafter, the V(2) lead always showed a saddleback-type ST elevation. At 25 years old, the late potential was positive and the electrophysiological study induced ventricular fibrillation. A challenge test with pilsicainide showed remarkable ST elevation by the V(2) lead. The 24-h Holter ECG monitoring showed remarkable ST elevation after eating a snack and during night time when the patient was asleep. The patient was diagnosed with Brugada syndrome and an implantable cardioverter-defibrillator was implanted. Genetic analysis did not reveal mutation of the SCN5A gene.
    Circulation Journal 01/2009; 73(3):575-9. · 3.77 Impact Factor
  • Source
    Article: Maternal vitamin A alters gene profiles and structural maturation of the rat ductus arteriosus.
    [show abstract] [hide abstract]
    ABSTRACT: Retinoic acid (RA), a metabolite of vitamin A, has been proposed to regulate vascular remodeling and reactivity of the ductus arteriosus (DA). Using rat Affymetrix GeneChips, we found that a considerable number of genes in DA varied their expression levels in accordance with developmental mode: namely, preterm-, term-, and postnatal-dominant clusters. Among a total of 8,740 probe sets, maternal vitamin A administration (MVA) changed the expression levels of 91 genes (116 probe sets) >2.5-fold. About half of preterm- and term-dominant genes responded to MVA, whereas only 5% of postnatal-dominant genes responded to MVA, indicating that fetal-dominant genes were susceptible to RA signals. The expression levels of 51 genes in MVA-treated DA at preterm were similar to the expression levels in nontreated DA at term, indicating that the global gene profile at preterm resembled that of the control animal at term. We observed neointima formation in MVA-treated DA at preterm in accordance with upregulation of fibronectin and hyaluronic acid, whereas it was rarely observed in nontreated DA at preterm. Five fetal cardiac myofibrillar genes were also upregulated in MVA-treated in vivo DA, whereas they were developmentally downregulated in nontreated DA. The present study indicates that MVA-mediated alteration in gene profile was associated with early structural maturation of DA, although MVA-mediated maturation may differ from normal vascular remodeling of DA.
    Physiological Genomics 10/2007; 31(1):139-57. · 2.73 Impact Factor
  • Article: Chronic activation of the prostaglandin receptor EP4 promotes hyaluronan-mediated neointimal formation in the ductus arteriosus.
    [show abstract] [hide abstract]
    ABSTRACT: PGE, a potent vasodilator, plays a primary role in maintaining the patency of the ductus arteriosus (DA). Genetic disruption of the PGE-specific receptor EP4, however, paradoxically results in fatal patent DA (PDA) in mice. Here we demonstrate that EP4-mediated signals promote DA closure by hyaluronic acid-mediated (HA-mediated) intimal cushion formation (ICF). Chronic EP4 stimulation by ONO-AE1-329, a selective EP4 agonist, significantly enhanced migration and HA production in rat DA smooth muscle cells. When HA production was inhibited, EP4-mediated migration was negated. Activation of EP4, adenylyl cyclase, and PKA all increased HA production and the level of HA synthase 2 (HAS2) transcripts. In immature rat DA explants, ICF was promoted by EP4/PKA stimuli. Furthermore, adenovirus-mediated Has2 gene transfer was sufficient to induce ICF in EP4-disrupted DA explants in which the intimal cushion had not formed. Accordingly, signals through EP4 have 2 essential roles in DA development, namely, vascular dilation and ICF. The latter would lead to luminal narrowing, helping adhesive occlusion and permanent closure of the vascular lumen. Our results imply that HA induction serves as an alternative therapeutic strategy for the treatment of PDA to the current one, i.e., inhibition of PGE signaling by cyclooxygenase inhibitors, which might delay PGE-mediated ICF in immature infants.
    Journal of Clinical Investigation 12/2006; 116(11):3026-34. · 15.39 Impact Factor
  • Article: Multiple transcripts of Ca2+ channel alpha1-subunits and a novel spliced variant of the alpha1C-subunit in rat ductus arteriosus.
    [show abstract] [hide abstract]
    ABSTRACT: Voltage-dependent Ca(2+) channels (VDCCs), which consist of multiple subtypes, regulate vascular tone in developing arterial smooth muscle, including the ductus arteriosus (DA). First, we examined the expression of VDCC subunits in the Wistar rat DA during development. Among alpha(1)-subunits, alpha(1C) and alpha(1G) were the most predominant isoforms. Maternal administration of vitamin A significantly increased alpha(1C)- and alpha(1G)-transcripts. Second, we examined the effect of VDCC subunits on proliferation of DA smooth muscle cells. We found that 1 microM nitrendipine (an L-type Ca(2+) channel blocker) and kurtoxin (a T-type Ca(2+) channel blocker) significantly decreased [(3)H]thymidine incorporation and that 3 microM efonidipine (an L- and T-type Ca(2+) channel blocker) further decreased [(3)H]thymidine incorporation, suggesting that L- and T-type Ca(2+) channels are involved in smooth muscle cell proliferation in the DA. Third, we found that a novel alternatively spliced variant of the alpha(1C)-isoform was highly expressed in the neointimal cushion of the DA, where proliferating and migrating smooth muscle cells are abundant. The basic channel properties of the spliced variant did not differ from those of the conventional alpha(1C)-subunit. We conclude that multiple VDCC subunits were identified in the DA, and, in particular, alpha(1C)- and alpha(1G)-subunits were predominant in the DA. A novel spliced variant of the alpha(1C)-subunit gene may play a distinct role in neointimal cushion formation in the DA.
    AJP Heart and Circulatory Physiology 05/2006; 290(4):H1660-70. · 3.71 Impact Factor
  • Article: Risk factors for arrhythmia and late death in patients with right ventricle to pulmonary artery conduit repair--Japanese multicenter study.
    [show abstract] [hide abstract]
    ABSTRACT: Arrhythmia and late cardiac deaths are thought to be major complications in patients after right ventricle (RV) to pulmonary artery (PA) conduit repair, although the incidence and predictors of these complications remain unknown. The aim of this study was to clarify the incidence and risk factors for arrhythmia and late deaths in patients with the RV to PA conduit repair through a Japanese multicenter study. Three hundred fifty-one hospital survivors who underwent the RV to PA conduit repair before 1995 were studied. Survival rate after repair was 92% at 10 years, 88% at 20 and 25 years, respectively. Late death was observed in 30 (8.5%) including 4 patients with sudden death (SD). Higher right ventricular pressure (p = 0.02), larger cardio-thoracic ratio after repair (p = 0.02) and higher incidence of brady- or tachy-arrhythmia and SD (9/30) were associated with late death. Six (1.7%) patients developed ventricular tachycardia or ventricular fibrillation (VT/Vf). There were 22 patients who had 23 new-onset supraventricular tachy-arrhythmia (SVT). Right ventricular hypertension (p = 0.04) was associated with VT/Vf or SD. Male sex (p < 0.01), absence of previously aorto-pulmonary shunt (p < 0.05), older age at repair (p < 0.01) or longer length of follow-up (p < 0.01) were associated with SVT. Arrhythmia and late sudden death are relatively common late after the RV to PA conduit repair. Our data support recent surgical strategies of earlier primary operation and timely reoperation for progressive right ventricular outflow stenosis that may reduce the incidence of late arrhythmias and SD.
    International Journal of Cardiology 02/2006; 106(3):373-81. · 7.08 Impact Factor
  • Article: Long-term course and clinical characteristics of ventricular tachycardia detected in children by school-based heart disease screening.
    [show abstract] [hide abstract]
    ABSTRACT: The prognosis of ventricular tachycardia (VT) in children with overt heart disease is generally good, so the aim of this study was to review the prognosis and necessity of treatment of VT that detected by school-based heart disease screening. Of the 48 cases of pediatric VT that have been followed for 2-30 years, 17% were diagnosed at the first school-based screening test (12-lead ECG at rest) and the remainder who had premature ventricular contractions (PVC) on the resting 12-lead ECG required Holter ECG test and exercise stress ECG test to detect VT. In 90% of cases, VT in healthy children is idiopathic non-sustained VT and more than half of the present cases showed natural disappearance of the VT during follow up. In particular, cases of monomorphic PVC or maximum PVC runs less than 5 had a good prognosis. The cases of polymorphic VT and VT with heart disease continued for the long term. Treatment is unnecessary for monomorphic VT with the maximum number of salvos less than 5. The necessity for treatment depends on the symptoms and profile of the VT. The prognosis for polymorphic VT and underlying heart disease is not good and may require implantable cardioverter defibrillator.
    Circulation Journal 04/2005; 69(3):273-6. · 3.77 Impact Factor
  • Article: Prevalence of right bundle-branch block and right precordial ST-segment elevation (Brugada-type electrocardiogram) in Japanese children.
    [show abstract] [hide abstract]
    ABSTRACT: The prevalence of Brugada-type electrocardiogram (ECG) in schoolchildren remains unclear. This study aimed to further investigate this condition. We studied the prevalence of Brugada-type ECG in 20,387 children (10,434 males and 9,953 females, 9.7 +/- 3.2 [SD] years old) during a school health examination in Kanagawa Prefecture, Japan, in 2002. We considered right bundle-branch block and ST-segment elevation of the J point of > or =0.1 mV in leads V1 through V3 as Brugada-like ECG, and an ECG was considered to be Brugada-type when the 12-lead ECG fully meet the criteria for the Brugada syndrome as recently published in a consensus report. Only 2 children (0.0098%, 95% confidence interval (CI): 0 to 0.023%) completely conformed to the criteria for Brugada-type ECG. Brugada-like ECG was found in 11 (10 male) of 20,387 children (0.054%, 95% CI: 0.022 to 0.086%). The prevalence in males was significantly higher than that in females, even in children (0.096% vs 0.010%, p=0.012). Stratified according to age, there was tendency for the prevalence of Brugada-like ECG to increase up to puberty (first graders, 0.01%; fourth graders, 0.05%; seventh graders, 0.08%; tenth graders, 0.23%; p=0.068). The prevalence of Brugada-type ECG in Japanese children was much lower than that reported in the adult population.
    Circulation Journal 04/2004; 68(4):275-9. · 3.77 Impact Factor
  • Article: Arrhythmias late after repair of tetralogy of fallot: a Japanese Multicenter Study.
    [show abstract] [hide abstract]
    ABSTRACT: Arrhythmia is a major late complication in adults with repaired tetralogy of Fallot, although a large-scale study has not been carried out in Japan. A nationwide multicenter study with 512 operative survivors was performed. Actuarial survival rate at 30 years (maximum follow-up) was 98.4%. Fifty-four patients (10.5%) had clinically important arrhythmias, including 23 patients with bradycardia caused by sick sinus syndrome or atrioventricular block (AVB). A patient with complete AVB (CAVB) without pacemaker implantation (PMI) died later. Two patients had sustained ventricular tachycardia (VT) and syncope was reported in 18 patients with ventricular arrhythmias (VA). Atrial tachyarrhythmias were observed in 13 patients. Older age at operation was a risk factor for atrial fibrillation/flutter, longer postoperative survival duration for VA, and QRS duration >120 ms for VT. Perimembranous ventricular septal defect was related to CAVB. Right ventricular outflow patch was not a risk factor. Importantly, 60% of the subjects had QRS duration <120 ms. The prevalence of serious arrhythmias is low in Japanese TOF patients as compared with the results from Western countries. CAVB without PMI and VT are the major risk factors for late morbidity and mortality. The excellent result could be related to the narrow QRS after surgery.
    Circulation Journal 02/2004; 68(2):126-30. · 3.77 Impact Factor
  • Article: Who is at risk for cardiac events in young patients with long QT syndrome?
    [show abstract] [hide abstract]
    ABSTRACT: The objective of this study was to determine who is at risk for cardiac events among young patients with long QT syndrome (LQTS) with or without a past history of LQTS-related cardiac events. The subjects were young patients with LQTS who had visited one of 36 hospitals from January 1997 to August 2000 in Japan. To predict the risk factors for cardiac events, stepwise regression analyses were performed for a total of 197 cases. There were 7 of 129 cases (5%) without a past history and 32 of the 68 (47%) cases with a past history of LQTS-related cardiac events that experienced new events after diagnosis (p<0.0001). Patients with a family history showed a higher incidence of symptoms both before and after diagnosis than patients with sporadic occurrence. Analyses revealed that noncompliance with medication and a lower age at diagnosis were significant predictors for the group with a past history. A negative predictive value <4 points was 100% in the group without a past history. To prevent future cardiac events, compliance with medication must be improved in those with a past history. A total LQTS score <4 points was useful to predict the absence of cardiac events in the group without a past history.
    Circulation Journal 12/2003; 67(12):1007-12. · 3.77 Impact Factor