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Takuya Yamazaki

Publications and source records attributed to Takuya Yamazaki.

14 recordsLinked to original sources
PubMed2006

Prognostic Significance of Quantitative QRS Duration.

BACKGROUND: Although QRS duration is known to be a predictor of mortality in patients with left ventricular dysfunction, our purpose was to evaluate the prognostic power of computer-measured QRS duration in a general medical population. METHODS: Analyses were performed on the first electrocardiogram digitally recorded on 46,933 consecutive patients at the Palo Alto Veterans Affairs Medical Center between 1987 and 2000. Patients with electrocardiograms exhibiting Wolff-Parkinson-White were excluded (n = 44), and those with bundle branch block or electronic pacing were considered separately, leaving 44,280 patients for analysis (mean age 56 +/- 15 years; 90% were males). There were 3659 (8.3%) cardiovascular deaths (mean follow-up of 6.0 +/- 3.8 years). RESULTS: A survival plot showed significant separation according to a QRS duration score. After adjustment in the Cox model for age, gender, and heart rate, the QRS duration score was a strong independent predictor of cardiovascular mortality. For every 10-ms increase in QRS duration, there was an 18% increase in cardiovascular risk. The results were similar in patients with an abnormal electrocardiogram, a bundle branch block, and a paced rhythm. CONCLUSION: Quantitative QRS duration was a significant and independent predictor of cardiovascular mortality in a general medical population.

Adult↗
PubMed2005

Prognostic importance of isolated T-wave abnormalities.

Computerized electrocardiograms recorded on 46,950 male veterans were analyzed to demonstrate the prognostic value of T-wave amplitude in a general medical population. There were 3,926 cardiovascular deaths over 6 years. Multivariate survival analysis allowed the development of a T-wave amplitude graphic that provides clinicians with a simple method of estimating the relative risk for cardiovascular mortality from T-wave amplitude in limb lead I.

Aged↗
PubMed2005

Electrocardiographic damage scores and cardiovascular mortality.

BACKGROUND: A number of electrocardiogram (ECG) classification systems have been developed to estimate cardiac injury, infarct size, and left ventricular function. Although many studies have documented an association between clinical, imaging, and autopsy data, few have evaluated their prognostic value. METHODS AND RESULTS: ECGs from 46,933 patients were analyzed using computerized measurements and algorithms. The Simplified Selvester Score, the Cardiac Infarction Injury Score (CIIS), and a Q-wave score were calculated. Other ECG characteristics such as left ventricular hypertrophy and bundle-branch blocks were also evaluated. The main outcome was cardiovascular (CV) mortality. During a mean follow-up of 6 years, the CIIS outperformed all other ECG classifications in determining prognosis. Going from lowest to highest tertile of CIIS, each step had a hazard ratio of 1.39 (CI 1.32-1.45) or a 39% increase in risk per tertile. Using clinically based thresholds, the annual mortality for high-risk CIIS was 4.5% (CI 4.0-4.6) versus 0.3% (CI 0.0-1.3) for those in the low-risk group. CONCLUSIONS: A low-risk damage score was associated with a <1% annual CV mortality and a high-risk damage score with annual CV mortality of >4%. A damage score should be calculated as part of all computerized ECG interpretations.

Aged↗
PubMed2005

Spatial QRS-T angle predicts cardiac death in a clinical population.

OBJECTIVES/BACKGROUND: The purpose of this study was to validate the prognostic value of computer-derived measurements of the spatial alignment of ventricular depolarization and repolarization from the standard 12-lead ECG in a general medical population. METHODS: Analyses were performed on the first ECG digitally recorded from 46,573 consecutive patients since 1987. QRS and T vector were synthesized by deriving XYZ leads from the 12 leads using the inverse Dower weighting matrix. Subset analyses were considered in patients with and those without standard ECG diagnoses (i.e., atrial fibrillation, Q waves, left ventricular hypertrophy, prolonged QRS duration). The main outcome measure was cardiovascular mortality. RESULTS: During a mean follow-up of 6 years, 4,127 cardiovascular deaths occurred. After adjusting for age, heart rate, and gender in a Cox regression analysis, spatial QRS-T angle was the most significant predictor of cardiovascular mortality, outperforming all other ECG measurements and diagnostic statements. In the subset with ECGs free of any standard diagnoses, annual cardiovascular mortality was 0.8% for normal (0-50 degrees ), 2.3% for borderline (50-100 degrees ), and 5.1% for abnormal (100-180 degrees ) QRS-T angle groups. The borderline and abnormal angle groups had 1.5- and 1.9-fold higher risk, respectively, relative to the normal QRS-T angle group after adjustment for age, gender, and heart rate. Similar results were found when patients with standard ECG diagnosis were included or compared. CONCLUSIONS: Spatial QRS-T angle is a significant and independent predictor of cardiovascular mortality that provides greater prognostic discrimination than any of the commonly utilized ECG diagnostic classifications.

Cardiovascular Diseases↗
PubMed2005

Phase I trial of weekly docetaxel and concurrent radiotherapy for head and neck cancer in elderly patients or patients with complications.

OBJECTIVE: We planned a phase I study of radiotherapy combined with weekly docetaxel for elderly patients or patients with complications to find out the optimal dose. METHODS: Five consecutive weekly administrations of docetaxel were accompanied by radiotherapy for patients diagnosed with squamous cell carcinoma of the head and neck. The starting dose of docetaxel was 10 mg/m(2) with escalation at 2 mg/m(2) per step. RESULTS: Fifteen patients were enrolled in this trial. The maximal tolerated dose was 14 mg/m(2), so the recommended dose was determined as 12 mg/m(2). Hematological toxicity was sufficiently weak. Common dose-limiting toxicity was stomatitis within the radiation field. CONCLUSIONS: This protocol was thought to be practical for elderly patients or those with medical complications.

Aged↗
PubMed2005

T-wave abnormalities are a better predictor of cardiovascular mortality than ST depression on the resting electrocardiogram.

BACKGROUND: ST depression and T-wave amplitude abnormalities are known to be independent predictors of cardiovascular (CV) death, but a direct comparison between them has not been described. METHODS: Analyses were performed on the first electrocardiogram (ECG) digitally recorded on 46,950 consecutive patients at the Palo Alto Veterans Affairs Medical Center since 1987. Females and patients with electrocardiograms exhibiting bundle branch block, left ventricular hypertrophy, electronic pacing, diagnostic Q waves, or Wolff-Parkinson-White syndrome were excluded, leaving 31,074 male patients for analysis (mean age 55 +/- 14). There were 1878 (6.0%) cardiovascular deaths (mean follow-up of 6 +/- 4 years). Electrocardiograms were classified using Minnesota code according to the degree of ST depression and T-wave abnormality, and the nine possible combinations of ST segment and T-wave abnormalities were recoded for analysis. RESULTS: The combination of major abnormalities in ST segments and T-waves carried the greatest hazard [3.2 (CI 2.7-3.8)]. Minor ST depression combined with more severe T-wave abnormalities carried a hazard of 3.1 (CI 2.5-3.7), whereas minor T-wave abnormalities combined with more severe ST depression carried a hazard of only 1.9 (CI 1.6-2.3). CONCLUSION: While both ST segment depression and abnormal T-wave amplitude are clinically important, T-wave abnormalities appear to be greater predictors of cardiovascular mortality.

Aged↗
PubMed2005

Effects of exercise training on left ventricular function evaluated by the Tei index in patients with myocardial infarction.

BACKGROUND: This study investigated the influence of exercise training on left ventricular (LV) function in patients with acute myocardial infarction (AMI) using a new index of cardiac function, the Tei index. METHODS AND RESULTS: The study enrolled 53 consecutive patients (36 males, 17 females; mean age: 65+/-10 years) with AMI. Exercise training was performed for 6 months; peak VO2 and the Tei index were measured at the start of the cardiac rehabilitation program and 1, 3, and 6 months later. The peak VO2 improved from 14.3+/-3.3 to 18.5+/-5.2 ml.min -1.kg-1 after 6 months (p<0.01). Although there were no significant changes in LV ejection fraction over the 6 months, the Tei index improved from 0.50+/-0.18 to 0.41+/-0.19 (p<0.05). When the DeltaTei index was compared among the 3 groups classified by the Tei index at baseline, the values improved in the groups with high/slightly high values compared with the normal group. CONCLUSION: Both cardiac function, as evaluated by the Tei index, and exercise capacity improved after exercise training in patients with AMI. The greater improvement was seen in the population with the higher value (lower cardiac function) according to this index.

Acute Disease↗
PubMed2004

Fitness versus physical activity patterns in predicting mortality in men.

PURPOSE: To compare the contributions of fitness level and physical activity patterns to all-cause mortality. METHODS: Of 6213 men referred for exercise testing between 1987 and 2000, 842 underwent an assessment of adulthood activity patterns. The predictive power of exercise capacity and activity patterns, along with clinical and exercise test data, were assessed for all-cause mortality during a mean (+/-SD) follow-up of 5.5 +/- 2 years. RESULTS: Expressing the data by age-adjusted quartiles, exercise capacity was a stronger predictor of mortality than was activity pattern (hazard ratio [HR] = 0.56; 95% confidence interval [CI]: 0.38 to 0.83; P < 0.001). In a multivariate analysis that considered clinical characteristics, risk factors, exercise test data, and activity patterns, exercise capacity (HR per quartile = 0.62; CI: 0.47 to 0.82; P < 0.001) and energy expenditure from adulthood recreational activity (HR per quartile = 0.72; 95% CI: 0.58 to 0.89; P = 0.002) were the only significant predictors of mortality; these two variables were stronger predictors than established risk factors such as smoking, hypertension, obesity, and diabetes. Age-adjusted mortality decreased per quartile increase in exercise capacity (HR for very low capacity = 1.0; HR for low = 0.59; HR for moderate = 0.46; HR for high = 0.28; P < 0.001) and physical activity (HR for very low activity = 1.0; HR for low = 0.63; HR for moderate = 0.42; HR for high = 0.38; P < 0.001). A 1000-kcal/wk increase in activity was approximately similar to a 1 metabolic equivalent increase in fitness; both conferred a mortality benefit of 20%. CONCLUSION: Exercise capacity determined from exercise testing and energy expenditure from weekly activity outperform other clinical and exercise test variables in predicting all-cause mortality.

Aged↗
PubMed2004

Treadmill scores in elderly men.

OBJECTIVES: This study seeks to further characterize the role of exercise testing in the elderly for prognosis and diagnosis of coronary artery disease. BACKGROUND: Recent exercise testing guidelines have recognized that statements regarding the elderly do not have an adequate evidence-based quality because the studies they are based on have limitations in sample size and design. The Duke Treadmill Score has been recommended for risk stratification, but recent evidence has suggested that it does not function in the elderly. METHODS: The study population consisted of male veterans (1872 patients >or=65 years; 3798 patients <65 years) who underwent routine clinical exercise testing with a mean follow-up of six years. A subset who underwent coronary angiography as clinically indicated (elderly, n = 405; younger, n= 809) were included. The primary outcome for all subjects was cardiovascular mortality with coronary angiographic findings as the outcome in those selected for angiography. RESULTS: In survival analysis, exercise-induced ST depression was prognostic in both age groups only when cardiovascular death was considered as the end point. Peak metabolic equivalents were the most significant predictor for both age groups only when all-cause death was considered as the end point. New age-specific prognostic scores were developed and found to be predictive for cardiovascular mortality in the elderly. Moreover, in the angiographic subset of the elderly, a specific diagnostic score provided significantly better discrimination than exercise ST measurements alone. For any new score, there is a need for validation in another elderly population. CONCLUSIONS: The mortality end point affected the choice of prognostic variables. This study demonstrates that exercise test scores can be helpful for the diagnosis and prognosis of coronary disease in the elderly.

Aged↗
PubMed2004

Do the right precordial leads during exercise testing contribute to detection of coronary artery disease?

BACKGROUND: It is still unknown whether or not the additional right precordial leads (RPL) during exercise testing contribute to detection of coronary artery disease (CAD). HYPOTHESIS: The aim of this study was to evaluate the RPL during exercise testing for the detection of CAD. METHODS: The study included 157 consecutive patients (116 men and 41 women, mean age 66 years) suspected of having CAD, who underwent conclusive treadmill exercise testing (heart rate reached at least 85% of the predicted maximum or positive electrocardiogram [ECG] changes were exhibited) and coronary angiography. During exercise testing, the ECG was recorded with the standard 12 leads and 4 RPL (V3R, V4R, V5R, V6R). RESULTS: Of the 157 patients, 67 had CAD (> 75% stenosis in at least one major coronary artery), and 64 had positive ST changes in the standard ECG leads during exercise testing. Using the conventional 12-lead method, sensitivity and specificity were 76 and 86%, respectively. Only three patients exhibited positive changes in the RPL leads; all had > 0.1 mV ST elevation in one of the RPL leads with > 0.1 mV ST elevation in aVR. Two of these patients had significant right coronary artery lesions and the other had a lesion of the left anterior descending artery which perfused the inferior as well as the anteroseptal area. In the standard 12 leads, one of the patients with an abnormal RPL and a right coronary lesion was negative, while the other two patients were positive. Combining RPL with the conventional 12-lead method, sensitivity and specificity were 78 and 86%, respectively. Therefore, RPL did not improve the accuracy of the exercise ECG. CONCLUSION: The use of RPL during exercise testing may contribute to the detection of ischemia perfused by the right coronary artery; however, it does not improve the diagnostic accuracy of the exercise test.

Aged↗
PubMed2004

Electrocardiographic arrhythmia risk testing.

Among the most compelling challenges facing cardiologists today is identification of which patients are at highest risk for sudden death. Automatic implantable cardioverter-defibrillators are now indicated in many of these patients, yet the role of noninvasive risk stratification in classifying patients at high risk is not well defined. The purpose of this review is to evaluate the various electrocardiographic (ECG) techniques that appear to have potential in assessment of risk for arrhythmia. The resting ECG (premature ventricular contractions, QRS duration, damage scores, QT dispersion, and ST segment and T wave abnormalities), T wave alternans, late potentials identified on signal-averaged ECGs, and heart rate variability are explored. Unequivocal evidence to support the widespread use of any single noninvasive technique is lacking; further research in this area is needed. It is likely that a combination of risk evaluation techniques will have the greatest predictive power in enabling identification of patients most likely to benefit from device therapy.

Arrhythmias, Cardiac↗
PubMed2004

Effect of age and end point on the prognostic value of the exercise test.

BACKGROUND: The clinical and exercise test variables chosen for predicting prognosis vary in the available studies. This could be due to the effect of age of the patients tested and the choice of outcomes used as end points in these follow-up studies. OBJECTIVE: To evaluate the effect of age and end points on exercise test variables chosen as significantly and independently associated with time to death. METHODS: Analyses were performed on the first treadmill test performed on consecutive male veterans at the Palo Alto and Long Beach Veterans Affairs Medical Centers since 1987. After removal of patients with congestive heart failure, coronary interventions, left bundle-branch block, atrial fibrillation, myocardial infarction and/or Q wave, and digoxin use, 3,745 male subjects remained. The outcomes were cardiovascular and all-cause mortality. The study population was divided into subsets according to age; exercise test and clinical variables were analyzed within the age subsets using the Cox hazard model. RESULTS: The mean age at the time of testing was 57 +/- 12 years (+/- SD) and they were followed up for a mean of 6.6 years. There were 544 all-cause deaths, with 206 of the deaths being due to cardiovascular causes (38%). When the study group was classified into subsets based on age, exercise capacity (in metabolic equivalents [METs]) was chosen by the Cox hazard model most consistently in the age groups using either end point. Even when age was added to the Duke treadmill score, prediction of death did not improve in those > 70 years of age because of the nonlinear relationship between age, the exercise test variables, and time to death. The most important age cut points for clinically important differences in exercise test predictors appeared to be 70 years and 75 years of age. In the patients 70 to 75 years of age, peak METs was the only variable predictive of all-cause mortality, and exercise-induced ST-segment depression was the only predictor of cardiovascular death; in the patients > 75 years of age, none of the exercise test responses were predictive of either death outcome. CONCLUSION: Both age and the outcome selected as an end point affect the exercise test responses chosen for scores to predict prognosis. Differences in age of the subjects tested and/or the outcome selected as the end point can explain the differences in the studies using exercise testing to predict prognosis.

Adult↗
PubMedDate not supplied

Single-institute phase I/II trial of alternating chemoradiotherapy with 5-FU and nedaplatin for esophageal carcinoma.

AIM: To assess the efficacy and feasibility of alternating chemoradiotherapy for esophageal cancer. MATERIALS AND METHODS: Patients, with previously untreated esophageal cancer, Eastern Cooperative Oncology Group performance status of 0 to 2, age 20 to 75 years and sufficient organ function, were eligible for this study. Three cycles of systemic chemotherapy with the continuous infusion of 3500 mg/m2 of 5-fluorouracil (5-FU: days 1-5) and a 6-h infusion of nedaplatin (NDP; day 6: 120-140 mg/m2), were accompanied by thoracic irradiation of 63 Gy in 35 fractions over 7 weeks. Radiation therapy was stopped during systemic chemotherapy (alternating setting). In the phase I part, the dose of nedaplatin was increased to define dose-limiting toxicities. For the phase II part, patients with distant metastasis were excluded. RESULTS: From 1998 through 2002, 40 patients were recruited for this protocol study. The median patient age was 54 years (range, 49-65 years) for the phase I and 58 years (range, 44-73 years) for the phase II trials. There were 35 men and 5 women in this study. For the phase I part (n = 15), the maximal tolerated dose of NDP was 140 mg/m2; thus, the recommended dose was 130 mg/m2. Twenty-five patients were treated with the recommended doses in the phase II part of the study. Ten patients had T4 disease and 14 patients had stage IV disease in the phase II part of the study. The overall survival rates at 1 and 2 years were 58.9% and 45.9%, respectively. The most frequent toxicities were leukopenia (grade 3 or greater: 80%), followed by thrombocytopenia (56%), granulocytopenia (56%) and anemia (28%). Radiation esophagitis of grade 3 or greater developed in 6 patients (24%). Two patients died of radiation pneumonitis. The actual dose intensities of NDP and 5-FU were 68.8% and 73.3%, respectively. CONCLUSION: This intensive treatment for esophageal cancer was feasible and effective; however, moderate-to-severe toxicity occurred. This protocol warrants further clinical evaluation in a multi-institutional prospective study.

Adult↗