Circulation Journal
Online ISSN : 1347-4820
Print ISSN : 1346-9843
ISSN-L : 1346-9843
Volume 66 , Issue 10
Showing 1-23 articles out of 23 articles from the selected issue
Clinical Investigation
  • Daiji Saito, Teruo Shiraki, Takefumi Oka, Akio Kajiyama, Toshiyuki Tak ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 877-880
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Little is known of the risk factors of recurrent myocardial infarction (MI) among Japanese patients who have survived their first MI. The risk factors for the second MI were studied in 808 of 1,042 consecutive patients who recovered from an acute MI in Iwakuni National Hospital. Multivariate logistic regression analysis revealed that only 3 of 21 variables measured were closely related with the recurrence of MI during a follow-up period of 3.2 ± 4.3 years: (1) transient atrial fibrillation (relative risk (RR) 3.16), (2) previous cerebrovascular accident (RR 3.05), and (3) dyslipidemia (RR 2.19). Of the parameters of dyslipidemia, a low ratio of high-density lipoprotein-holesterol (HDL-C) to low-density lipoprotein-cholesterol (LDL-C) alone indicated subsequent MI. None of age, gender, location of the infarction, hypertension, diabetes mellitus, pulmonary congestion (Killip's class ≥2), peak serum creatine kinase activity, serum total-cholesterol, HDL- and LDL-cholesterol levels, nor smoking habit on admission was a statistically significant predictor for the second MI. The result suggests that more intensive treatment is needed for patients with the 3 risk factors. (Circ J 2002; 66: 877 - 880)
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  • Kinji Ishikawa, Akio Kimura, Takaaki Taniwa, Toshihiko Takenaka, Takah ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 881-885
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Recent trends in the treatment of post-myocardial infarction (MI) patients and the factors accounting for the improvement in outcome are presented. A total of 6,602 post-MI patients (5,320 males, 1,282 females; 58.9±10.4 years of age) enrolled between 1986 and 1999 were followed up for an average of 12.6±16.3 months. The incidence of cardiac events, which included fatal and nonfatal recurrent MIs, sudden death and death by congestive heart failure, was highest (44.9 events/1,000 person · year) in 1986-1987, but decreased steadily to 22.5 events/1,000 person · year by 1997-1999 (Trend p<0.0001). This trend accompanied the increased use of coronary thrombolysis, percutaneous transluminal coronary angioplasty and coronary artery bypass graft surgery, increased prescription of antiplatelet agents (51.5%→83.4%), lipid-lowering agents (29.8%→52.6%) and angiotensin-converting enzyme inhibitors (5.3%→41.0%), and reduced prescription of calcium antagonists (68.5%→41.0%) and nitrates (60.7%→45.7%). These changes in treatment have led to a decreased incidence of angina pectoris, wall motion abnormalities and abnormal Q waves on electrocardiograms. The decline in the incidence of cardiac events among post-MI patients in the 14 years between 1986 and 1999 reflects implementation of new therapeutic modalities proven to be effective in clinical trials and in daily practice. (Circ J 2002; 66: 881 - 885)
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  • Chien-Ming Huang, Mason-Shing Young
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 886-890
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    The present study examined the effect of treatment with angiotensin-converting enzyme inhibitors (ACEIs) on the long-term prognosis in 119 patients with dilated cardiomyopathy (DCM). Conventional therapy was used in 29 patients and 90 patients were treated with ACEIs: 50 were taking captopril and 40 were taking enalapril; 24 were taking ≥75 mg captopril or ≥20 mg enalapril daily (high-dose group) and 66 patients received smaller doses (low-dose group). No significant differences between groups were detected with respect to demographics and clinical signs of congestive heart failure (CHF). During follow-up, 65 patients survived and 54 patients died: 34 patients were in group 1 and 20 patients were in the placebo group. Patients treated with ACEIs had a significantly better survival during the first to third year, but the difference was not significant between the high- and low-dose groups. Comparison of the cumulative probability of death in the enalapril and captopril groups showed a trend of significant reduction of mortality by 13% in the enalapril group (p<0.10). These data indicate that ACEIs have a beneficial effect on prolonging the short- and long-term survival in DCM patients, so it is strongly recommended that all patients with DCM should be treated with ACEIs unless contraindicated. In this study, lower doses of ACEI seemed prognostically equivalent to higher doses, and enalapril appeared to be preferable to captopril in the treatment of severe CHF. Additional prospective large studies are necessary to verify the relationship observed here between the optimal dosage as well as the duration of action of different ACEIs and their outcomes. (Circ J 2002; 66: 886 - 890)
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  • Issei Uchida, Hiroshi Takaki, Yoshio Kobayashi, Yoshiaki Okano, Toru S ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 891-896
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Correlations between baseline hemodynamic and oximetric variables during an invasive exercise test and an improvement in peak oxygen uptake (peak Vo2) after exercise training (ET) were examined in 20 patients who participated in a cardiac rehabilitation program after acute myocardial infarction (AMI). Peak Vo2 significantly increased by 23±21% (p<0.01) after ET and the improvement best correlated with the change in O2 extraction fraction ([arterial O2 content - venous O2 content] / arterial O2 content) during an exercise test before ET (r=-0.61, p<0.01). Exercise capacity was improved to a greater extent by ET in patients with a smaller increase in O2 extraction fraction during an exercise test before ET. Thus, O2 extraction fraction during an exercise test before ET may be a useful predictor of the improvement in exercise capacity after ET in post-AMI patients. (Circ J 2002; 66: 891 - 896)
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  • Takahide Ito, Michihiro Suwa, Shuji Suzuki, Mitsuhiro Tanimura, George ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 897-901
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Cyclic variation (CV) of myocardial integrated backscatter (IBS), which reflects intrinsic contractile performance, can predict myocardial viability in patients with a reperfused acute myocardial infarction (MI), but the use of this method has not been validated for chronic left ventricular (LV) dysfunction. The aim of this study was to examine whether myocardial IBS was useful for predicting LV functional recovery after coronary revascularization in 17 patients with prior anterior MI and LV dysfunction (ejection fraction <50%). Within 24 h of the revascularization procedure (percutaneous transluminal coronary angioplasty or coronary stenting), IBS curves were obtained by placing the region of interest on the anterior wall on the short-axis IBS image. The patients had repeat left heart catheterization at 3 or 6 months after the revascularization procedure, and were grouped according to the patterns of the IBS curve within the anterior wall. In 8 patients (group A), the IBS curve had a synchronized pattern with the magnitude of CV ≥3.5, and in the remaining 9 patients (group B), the curve had either an asynchronized pattern or the magnitude of CV was less than 3.5 dB even in the case of synchronized pattern, or both. At baseline, there were no significant differences in LV functional indices between the 2 groups. After the follow-up period, the LV end-systolic volume decreased (75±21 ml to 56±20 ml, p=0.05), LV ejection fraction increased (35±12% to 50±14%, p=0.014), and LV end-diastolic pressure decreased (19±10 mmHg to 13±6 mmHg, p=0.02) in group A, whereas only the LV ejection fraction increased (34±9% to 40±11%, p=0.03) in group B; LV end-systolic volume (72±19 ml to 66±16 ml, p=0.126) and LV end-diastolic pressure (18±12 mmHg to 14±8 mmHg, p=0.184) showed no significant changes. In conclusion, IBS is valuable for predicting LV functional recovery after coronary revascularization in patients with LV dysfunction caused by a remote anterior MI. A large-scale study is be needed to establish these data. (Circ J 2002; 66: 897 - 901)
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  • Jiro Koyama, Jun Watanabe, Aki Yamada, Yoshito Koseki, Yuji Konno, Sun ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 902-907
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    The significance of heart-rate turbulence (HRT) in patients with chronic heart failure (CHF) was evaluated to examine whether it is sensitive to the risk of ventricular tachycardia (VT). HRT is reported to predict the prognosis after myocardial infarction (MI), but its prognostic value in patients with CHF remains unknown. HRT was measured in 50 CHF patients (left ventricular ejection fraction <50% and/or left ventricular end-diastolic diameter >55 mm, 34 cardiomyopathy, 16 post-MI) and 21 patients without obvious heart diseases (control). HRT slope and HRT onset were measured by the original definitions using digitized Holter ECG recordings. Cardiac pump function was assessed by echocardiography. The value of the HRT slope was significantly lower in CHF than in control (3.7±1.7 vs 16.4±5.3, mean ± SD, p<0.01). The value of the HRT onset in patients with CHF was significantly higher than that in control patients (-1.1±1.9 vs -3.6±1.7, mean ± SD, p<0.05). The HRT slope and onset in CHF patients with VT were nearly identical to those without VT. The HRT slope appears to be a powerful prognostic marker that shows significant differences between CHF subgroups when divided by clinical events; that is, CHF death and CHF hospitalization. However, it has limited value for predicting fatal ventricular arrhythmias. (Circ J 2002; 66: 902 - 907)
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  • You-Bin Deng, Hui-Juan Xiang, Qing Chang, Chun-Lei Li
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 908-912
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Previous studies in patients with a history of Kawasaki disease (KD) have focused on the endothelial function of the coronary arteries and that of the systemic arteries is not fully understood. Furthermore, the effect of vitamin C on systemic vascular endothelial function after KD has not yet been elucidated. In the present study, 39 patients (age, 7.1±2.7 years) at 1-10 years after acute KD were compared with 17 matched healthy subjects (7.0±3.1 years). High-resolution ultrasonography was used to analyze brachial artery responses to reactive hyperemia (with increased flow causing endothelium-dependent dilation) and sublingual nitroglycerin (causing endothelium-independent dilation) after KD, and to investigate whether the acute administration of vitamin C can restore systemic endothelial dysfunction. The percent change in diameter of the brachial artery induced by reactive hyperemia in the patients with a history of KD (6.2±3.9%) was significantly less than that in the control group (14.1±6.8%, p<0.0001). No significant difference could be found in the percent change in diameter induced by sublingual nitroglycerin between the controls (33.2±13.7%) and the patients (30.6±9.2%, p=0.49). There was no significant difference in percent change in diameter of the brachial artery induced by reactive hyperemia between the patients who received gamma globulin (6.0±4.0) and those who did not (7.9±3.3, p=0.33). Intravenous infusion of vitamin C significantly increased the percent change in diameter of the brachial artery induced by reactive hyperemia in 19 patients with history of KD (6.6±3.5% to 13.0±5.5%, p<0.0001). After placebo administration in 20 patients with history of KD there was no significant increase in the percent change in the diameter of the brachial artery induced by reactive hyperemia (6.5±4.5% to 7.3±4.9%, p=0.20). The decreased percent change in the diameter of the brachial artery induced by reactive hyperemia in patients with a history of KD compared with the healthy children indicates that systemic endothelial dysfunction exists after KD. Although it is not influenced by early treatment with high-dose gamma globulin in the acute stage of KD, systemic vascular endothelial function can be restored by acute intravenous administration of vitamin C. (Circ J 2002; 66: 908 - 912)
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  • Xiaoyan Zhou, Yutaka Otsuji, Shiro Yoshifuku, Toshinori Yuasa, Hui Zha ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 913-916
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    To investigate the effects of atrial fibrillation (AF) on the mitral and tricuspid valves, the corresponding annular dilatation and valvular regurgitation were compared with 2-dimensional and Doppler echocardiography in 31 consecutive patients with lone AF and 28 normal controls. Mid-systolic mitral and tricuspid annular areas were measured from 2 diameters in 2 orthogonal apical echocardiograms. Percent (%) mitral regurgitant (MR) or tricuspid regurgitant (TR) jet area to the left or right atrial area was evaluated and % MR or TR jet area >20% was considered moderate or significant. Both the mitral and tricuspid annular areas in patients with lone AF were significantly larger compared with the controls (mitral: 9.5 ±1.2 vs 6.6±0.9 cm2, lone AF vs control, p<0.01) (tricuspid: 12.0±2.0 vs 7.5±0.9 cm2, p<0.01). The % increase in the annular area relative to the mean normal value was significantly greater in the tricuspid valve (44±18 vs 60±28%, p<0.01). Moderate or severe MR was not observed and the incidence of moderate or severe valve regurgitation (% jet area >20%) was significantly higher in the tricuspid valve (0/31 vs 11/31, MR vs TR, p<0.01) in patients with lone AF. The % TR jet area showed significant correlation with tricuspid annular area (r2 = 0.65, p<0.001). Lone AF is associated with annular dilatation of both mitral and tricuspid valves, but the annular dilatation and valvular regurgitation are significantly greater in the tricuspid valve. (Circ J 2002; 66: 913 - 916)
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  • Satoshi Kurisu, Ichiro Inoue, Takuji Kawagoe, Masaharu Ishihara, Yuji ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 917-920
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    The impact of coronary stenting on microvascular circulation in the infarct area was compared with that of balloon angioplasty in 94 patients with acute myocardial infarction (AMI) who underwent coronary revascularization within 6 h of onset: 49 patients were treated with balloon angioplasty alone, and 45 were treated with coronary stenting. Microvascular circulation after revascularization was assessed by Thrombolysis in Myocardial Infarction (TIMI) flow grade analysis and ST segment analysis. TIMI flow grade was assessed on the final angiographic image after coronary intervention, and the ST segment was assessed on the 12-lead electrocardiogram recordings just before revascularization and on return to the coronary care unit. The distributions of TIMI flow grade and change in ΣST (5.1±10.8 vs 5.1±9.9 mm) were similar between the 2 groups. Predischarge left ventricular ejection fraction (54±14 vs 54±15%) and in-hospital outcome were also similar between the 2 groups. The data suggest that coronary stenting did not influence microvascular circulation (improvement or detriment) in patients with reperfused AMI. (Circ J 2002; 66: 917 - 920)
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  • Nobuhiko Hayashida, Hideki Teshima, Shingo Chihara, Hiroshi Tomoeda, T ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 921-925
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    It is well known that the use of cardiopulmonary bypass (CPB) influences renal function and occasionally results in renal failure following cardiac surgery. Coronary artery bypass grafting (CABG) without CPB may avoid this and preserve the perioperative renal function. The present study enrolled 52 patients undergoing CABG without CPB (OPCAB group) and matched them for renal function and prognostic variables with 53 patients undergoing conventional CABG (CABG group). Perioperative renal function and early clinical results were assessed. The OPCAB group had significantly less increase in creatinine levels (0.16±0.05 vs 0.45±0.06 mg/dl; p=0.01) and greater creatinine clearance (81.6±7.3 vs 56.3±4.8 ml/min; p=0.01) postoperatively. Postoperative recovery of free water clearance was more prompt in the OPCAB group. The duration of intubation and intensive care unit stay was significantly shorter, and the creatine kinase-MB release and blood transfusion requirements were significantly less in the OPCAB group. The OPCAB technique preserved glomerular filtration rate and prevented the increase in creatinine levels. The results suggest that the technique enables earlier patient recovery and gives superior renal protection compared with conventional CABG. (Circ J 2002; 66: 921 - 925)
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  • Kimiaki Komukai, Koichi Hashimoto, Takahiro Shibata, Keiji Iwano, Mako ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 926-929
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Continuous ATP injection is used clinically for Tl imaging or coronary flow measurement and because the effect on human hemodynamics is unknown, the present study investigated it in 14 patients undergoing heart catheter examination. Continuous ATP injection induced chest symptoms in 13 of the patients and second-degree atrioventricular block in one, but these complications disappeared immediately after the end of ATP infusion. Continuous ATP injection decreased aortic pressure, but increased pulmonary artery pressure, right atrial pressure and pulmonary capillary wedge pressure. ATP increased heart rate, stroke volume and cardiac output, the latter the result of an increase in preload, a decrease in afterload, and the increase in heart rate. (Circ J 2002; 66: 926 - 929)
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  • Yoichi Goto, Hitoshi Sumida, Kenji Ueshima, Hitoshi Adachi, Ryuji Noha ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 930-936
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    The purpose of this study was to determine the incidence of subacute stent thrombosis related to exercise testing (ETT) or exercise training in cardiac rehabilitation (exercise cardiac rehabilitation (ECR)) and to clarify the appropriate timing of ETT and ECR in patients with acute myocardial infarction (AMI) treated with coronary stenting, because the safety and appropriate timing of ETT and ECR after coronary stenting for AMI have not been established. Forty-six institutes performing emergency percutaneous coronary intervention (PCI) for AMI were surveyed for the incidence of exercise-related subacute stent thrombosis and the timing of the start of ETT and ECR in patients with AMI in 1996-1998. Among the total 13,685 patients with AMI, 4,360 (31.9%) underwent coronary stenting. Of the 132 (3.0%) subacute stent thromboses that developed within 1 month after stenting, only one event was related to maximal ETT and occurred in a patient not receiving ticlopidine. No stent thrombosis occurred in association with submaximal ETT or ECR. In 7 institutes, maximal ETT was routinely performed at 14 days after stenting for AMI without any adverse events, and in 6 institutes, ECR was routinely started within 7 days without any adverse events. This survey found that only 21.0% of all AMI patients participated in ECR. In conclusion, subacute stent thrombosis related to ETT or ECR is extremely rare (0-0.02%) in patients with AMI, especially when they are receiving ticlopidine, and therefore ETT and ECR for stented patients with AMI need not be delayed (ie, approximately 7 days after stenting for submaximal ETT and ECR, and 14 days after stenting for maximal ETT). The rate of participation of post-AMI patients in ECR is low in Japan, even in major hospitals that are actively working in the field. (Circ J 2002; 66: 930 - 936)
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  • Tatsuya Sasaki, Takashi Kubo, Tetsuya Miyamoto, Kazuo Komamura, Kaduo ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 937-942
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    The aim of this study was to determine whether left atrial (LA) function contributes to pulmonary circulatory pressure during pacing-tachycardia and exercise capacity in patients with idiopathic dilated cardiomyopathy (DCM). Thirty-two patients with DCM and in sinus rhythm had limited exercise capacity because of dyspnea. The correlation between peak oxygen consumption (VO2) and the variables of cardiac function by cardiac catheterization and 2-dimensional, Doppler echocardiography, and plasma neurohumoral factor levels was tested, as was the correlation between non-invasive LA functional parameters and pulmonary circulatory pressure during pacing-tachycardia. A significant correlation was observed between VO2 and LA dimension (r=-0.45, p<0.01), the peak velocities of LA appendage empty flow during atrial systole (r=0.63, p<0.0001) and the pulmonary venous forward flow in early ventricular systole (PVS1; r=0.74, p<0.0001), as well as plasma brain natriuretic peptide (BNP) concentrations. The predictable equation to VO2 with the multiple regression analysis was : VO2=-0.01 BNP+0.21 PVS1+15.4 (r=0.81, p<0.0001). Furthermore, LA functional variables derived from pulmonary venous flow, especially PVS1, but not plasma BNP concentration, were useful for predicting the degree of the increase in pulmonary circulatory pressure during pacing-tachycardia. Therefore, it is suggested that LA function contributes to exercise capacity through its influence on pulmonary hemodynamic reserve in patients with DCM with sinus rhythm whose exercise is limited by dyspnea. (Circ J 2002; 66: 937 - 942)
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  • Naoki Isobe, Shigeru Oshima, Koichi Taniguchi, Hiroshi Hoshizaki, Hito ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 943-948
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Nicorandil is an antianginal drug that exerts both a conventional nitrate effect and an independent ATP-dependent potassium channel-opening effect. The present study examined the effects of nicorandil on left ventricular regional work (RW) during coronary angioplasty in 22 patients with angina pectoris who were scheduled for angioplasty to the left anterior descending artery. The patients were randomly assigned to receive either nitroglycerin (group NG, n=12, 0.5 μg · kg-1 · min-1) or nicorandil (group NR, n=10, 1.5 μg · kg-1 · min-1). Inflation was performed for 60 s and the data were collected every 10 s. The RW was derived from the relation between mean wall stress and area strain. The RW of the interventricular septum decreased after balloon inflation and was at its minimum after the 60 s inflation (group NR: 1.24±0.72 mJ/cm3, group NG: 0.63±0.25 mJ/cm 3). After balloon deflation, the septal RW of both groups increased, and recovered to the baseline condition at about 30 s. At 20 s after deflation, the septal RW in group NR (3.58±1.17 mJ/cm3) was significantly higher than that in group NG (2.25±0.59 mJ/cm3) (p<0.05). An intravenous infusion of nicorandil led to good recovery of RW from ischemia compared with that obtained with nitroglycerin. (Circ J 2002; 66: 943 - 948)
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  • Tadashi Fujiwara, Hisataka Sasao, Akita Endo, Tohru Hasegawa, Yuka Kik ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 949-953
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Results of trials using the ACS MULTI-LINK (ML) stent, one of the new generation stents, were similar to or slightly better than those of trials using the Palmaz-Shatz stent. The purpose of this study was to evaluate relatively long-term (2 years) clinical outcomes of patients with coronary artery disease treated with the ML stent and to determine independent factors correlated with target lesion revascularization and cardiac events. The present study consisted of 82 consecutive patients who had undergone successful coronary ML stent implantation from January 1997 to December 1999. During the follow-up period, cardiac events occurred in 16 (19.5%) patients. All patients underwent follow-up angiography and 12 (14.6%) of the 82 patients underwent target lesion revascularization. Multiple logistic regression analysis showed that aggregation of risk factors (≥3 risk factors) (p=0.0274, odds ratio=5.14) and percent diameter stenosis >20% (p=0.0395, OR=4.586) were the significant explanatory factors of target lesion revascularization. In addition, aggregation of risk factors (≥3 risk factors) exhibited a tendency to correlate with cardiac events (p=0.0528) on multiple logistic regression analysis. The results of the present study suggest that target lesion revascularization after coronary ML stent implantation was influenced by aggregation of major coronary risk factors and residual percent diameter stenosis and that long-term clinical outcome is influenced by the aggregation of risk factors. (Circ J 2002; 66: 949 - 953)
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Experimental Investigation
  • Eisaku Satoh, Kyoichi Ono, Feng Xu, Toshihiko Iijima
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 954-958
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Transient receptor potential protein 4 (TRPC4) has been identified as a candidate for the capacitative calcium entry (CCE) channels, but its functional role is still controversial. Using a RT-PCR technique, a novel isoform of TRPC4, designated rTRPC4 γ, was isolated. It was nearly identical to full-length rTRPC4 (rTRPC4α), except that it lacked 53 nucleotides that correspond to the predicted linker between the second and third transmembrane domain of rTRPC4α, and its mRNA was expressed in brain and heart. This splice variant encoded a potential protein of 400 residues that consists of an amino-terminal cytoplasmic domain and 2 transmembrane domains by a frameshift mutation. When rTRPC4 γ cDNA was transiently transfected to HEK-293 cells, thapsigargin (TG)-induced Ca2+ entry was suppressed significantly. By contrast, expression of rTRPC4α did not affect TG-induced Ca2+ entry. To investigate the subcellular localization, plasmids were constructed with green fluorescence protein (GFP) as an amino-terminal fusion to rTRPC4 variants. GFP-rTRPC4γ fusion protein, unlike GFP-rTRPC4 α, was localized to the cytoplasm as well as plasma membrane. These results suggest that rTRPC4γ may play a modulatory role in CCE channel activity in the brain and heart. (Circ J 2002; 66: 954 - 958)
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  • Sang-Hyun Kim, Hyo-Soo Kim, Myoung-Mook Lee
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 959-964
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Molecular switches between the troponin T and I isoforms are known to occur in various conditions, but the results from studies of failing human hearts with various etiologies are contradictory and it is not certain whether troponin isoform changes occur. Therefore, the molecular switching of troponin isoforms during normal development and heart failure (HF) after myocardial infarction were investigated in Sprague-Dawley rats at the fetal, neonate, and normal adult stages, and in a postinfarction adult HF group. During normal development, switching from the fetal to the adult pattern of the troponin T and I isoforms was observed. Immunoblotting of postinfarction failing hearts revealed a marked increase in the fetal isoform of cardiac TnT (cTnT) (fetal/adult cTnT isoforms: normal adult = 0.61±0.09 vs postinfarction HF = 1.59±0.13, p<0.001). Also, the amount of the adult troponin I (TnI) isoform decreased significantly in the postinfarction failing heart. In the semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) with glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) as an internal standard, the mRNA of fetal cTnT increased in the postinfarction failing heart (fetal cTnT/GAPDH: control = 0.22 vs HF rat = 0.84, p<0.05). Therefore, molecular switching of the troponin T and I isoforms occurred during the normal development of the rat, and there was re-expression of the fetal pattern of the isoforms in the postinfarction failing heart of the adult rat. (Circ J 2002; 66: 959 - 964)
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  • Takayuki Ohwada, Toshiyuki Ishibashi, Hiroyuki Yaoita, Joji Shindo, Hi ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 965-971
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    It remains to be clarified how angiotensin-converting enzyme inhibitor-induced function (ie, increased NO related action or the inhibition of angiotensin II AT1 receptor dependent action) affects apoptosis of smooth muscle cells in the neointima following arterial injury. Saline (control), enalapril, L-arginine, combined enalapril and L-arginine, or losartan was administered for 14 days to Sprague-Dawley rats after balloon carotid injury and the ratio of intima to media areas (I/M), inducible NO synthase (iNOS) concentrations and %TUNEL were measured. I/M decreased similarly in the enalapril, L-arginine and losartan groups, and the combination of enalapril and L-arginine resulted in the largest I/M decrease. TUNEL positivity was increased compared with controls in the following order: losartan, L-arginine, enalapril and combination of enalapril and L-arginine. The intensity of immunostaining for iNOS was increased approximately 1.9-fold compared with the control in the combined enarapril and L-arginine group as well as in the enalapril group. These data suggest that the apoptosis in the neointima is different for L-arginine, losartan and enalapril under similar conditions and was higher under treatment with enalapril, not only via the action of NO or blocking of the AT1, but also by upregulation of iNOS. (Circ J 2002; 66: 965 - 971)
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Case Report
  • Tohru Takaseya, Masaru Nishimi, Takemi Kawara, Eiki Tayama, Shuji Fuku ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 972-973
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Spontaneous coronary artery dissection (SCAD) is a rare cause of myocardial infarction (MI). A 66-year-old Japanese man, who had had an anterior wall MI caused by SCAD of the left anterior descending coronary artery, developed left ventricular aneurysm 5 years later, with depressed left ventricular function and thrombus observed on echocardiography. Left endoventricular circular patch plasty according to Dor's technique was performed without coronary artery bypass grafting, because of the absense of significant coronary artery stenosis on the preoperative coronary angiogram. The clinical course of SCAD in the late phase is generally favorable, but because the prognosis of SCAD is uncertain, patients with SCAD should be carefully followed. (Circ J 2002; 66: 972 - 973)
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  • Masahiro Ikeda, Hirokazu Ohashi, Yasushi Tsutsumi, Takahiro Kawai, Mas ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 974-976
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Cardiac rupture after acute myocardial infarction (AMI) in patients with aortic valve stenosis (AS) is uncommon and only 2 survival cases after surgery have been reported to date. The present patient, a 69-year-old woman with aortic valve stenosis (AS), suffered an acute myocardial infarction and despite a successful baloon angioplasty to the proximal left anterior descending artery, the condition progressed into congestive heart failure. Echocardiography demonstrated AS with a valve area of 0.7 cm2 and a left ventricular aneurysm with a thin and dyskinetic anterior to apical wall. An urgent operation was performed and the opening of the pericardium revealed oozing rupture of the aneurysm. An endoventricular circular patch plasty combined with aortic valve replacement was successfully performed, and good results during 2-year follow-up were achieved. Physiological repair with exclusion of the infarcted area is essential to achieve a good long-term outcome in such a critical case. Special care should be taken with AMI in a patient with AS because of the possible occurrence of aneurysm and rupture of the left ventricle. (Circ J 2002; 66: 974 - 976)
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  • Keisuke Shioji, Yasushi Matsuura, Tomoyuki Iwase, Shouji Kitaguchi, Ha ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 977-980
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    A 31-year-old woman suspected to have acute myocarditis was admitted to hospital and was managed with intra-aortic balloon pumping and a percutaneous cardiopulmonary support system because of sustained ventricular tachycardia. After immunoglobulin treatment, cardiac function and systematic inflammation were improved. The left ventricular endomyocardial biopsy revealed massive necrosis and degeneration of myocardial cells, and extensive infiltration of inflammatory cells. The clinicopathology of this patient was thought to be fulminant myocarditis. Serial serum thioredoxin (TRX) analysis showed that the serum level was high during the acute phase, and decreased during the chronic phase. Immunohistochemistry for TRX in the biopsy samples showed that inflammatory cells and cardiomyocytes were positively stained. (Circ J 2002; 66: 977 - 980)
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  • Hiroyuki Watanabe, Satoshi Kibira, Takashi Saito, Hiroshi Shimizu, Toy ...
    Type: scientific monograph
    Subject area: None
    2002 Volume 66 Issue 10 Pages 981-984
    Published: 2002
    Released: October 17, 2002
    JOURNALS FREE ACCESS
    Sustained ventricular tachycardia (VT) developed in a 63-year-old woman. The 2-dimensional echocardiogram revealed left mid-ventricular obstructive hypertrophy and a discrete apical chamber. A continuous wave Doppler signal across the mid-ventricular narrowing exhibited early systolic ejection flow and diastolic paradoxical jet flow from the apex to the basal chamber, implying a significant systolic and diastolic intraventricular gradient with a high apical pressure. The left ventriculogram confirmed a mid-ventricular obstruction with an apical aneurysm. Invasive assessment of intraventricular pressure showed a peak-to-peak gradient greater than 100 mmHg. Treatment with antiarrhythmic agents could not prevent the VT, but dual-chamber pacing reduced the intraventricular pressure gradient and suppressed the VT completely. Continuous wave Doppler showed that the early systolic ejection flow from the apex had disappeared, that there was isovolumetric relaxation flow toward the apex and that there was attenuation of the diastolic paradoxical jet flow toward the basal chamber. Such findings by continuous wave Doppler can be useful in pacing therapy for evaluating changes in the severity of mid-ventricular obstruction. (Circ J 2002; 66: 981 - 984)
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