Normal limits of ejection fraction and volumes determined by gated SPECT in clinically normal patients without cardiac events: A study based on the J-ACCESS database

金沢大学大学院医学系研究科がん制御学Purpose: Quantitative gated single-photon emission computed tomography (SPECT) is known to have high accuracy and precision for measurement of the principal cardiac functional parameters. We hypothesised that normal values for EF and LV volumes may differ among nationalities, and that optimal threshold values specific to the study population are required. Methods: Among 4,670 consecutively registered patients for a J-ACCESS (Japanese investigation regarding prognosis based on gated SPECT) study from 117 hospitals, a total of 268 (149 women, 119 men) were selected who had no baseline cardiac diseases and had experienced no cardiac events during the preceding 3-year period. A gated SPECT study was performed with 99mTc-tetrofosmin and analysed with Cedars Sinai Medical Center\u27s quantitative gated SPECT (QGS) software. The results in respect of ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV) and stroke volume (SV), and EDV, ESV and SV normalised by body surface area (EDVI, ESVI and SVI), were calculated and summarised to obtain normal limits. Results: EF for women and men was 74 ± 9% and 63 ± 7%, respectively (p < 0.0001). EDV, ESV and SV were significantly smaller in women than in men. Based on multiple regressions for linear models, the primary and secondary predictors of EF, EDVI, ESVI were gender and age. By stepwise multiple regression analysis, a statistically significant third predictor for EDV, ESV, SV and SVI was body weight. No colinearity was found between age and body weight. Important factors for the studied Japanese population included a high incidence of small hearts in women and the relatively advanced age of the population (the mean age ±SD was 64.1 ± 10.0 years for women and 60.9 ± 11.7 years for men). Conclusion: EF and volumes determined by gated SPECT with QGS were significantly affected by gender and age, with body weight as a third predictor for volumes. Moreover, the normal limits were so specific for the population studied that standards appropriate for the study in question should be utilised. © 2007 Springer-Verlag

Prognostic value of myocardial perfusion and ventricular function in a Japanese multicenter cohort study (J-ACCESS): the first-year total events and hard events

金沢大学医薬保健研究域医学系Objective: To determine the prognostic value of myocardial ischemia, function and coronary risk factors on total and hard cardiac events using myocardial perfusion imaging in a Japanese population. Methods: A prospective cohort study was performed in 117 Japanese hospitals, each with a nuclear cardiology facility. A total of 4,031 patients with suspected or confirmed ischemic heart disease were registered. The patients were followed up for a year to investigate total and hard events, and those who had any events were followed up for 3 years to evaluate subsequent hard events. A stress-rest gated myocardial perfusion study was performed with 99mTc-tetrofosmin using gated single-photon emission computed tomography (SPECT) and analyzed by semi-quantitative scores. Results: During the 1-year follow-up period, 263 (6.5%) patients had total events comprising all-cause death, non-fatal myocardial infarction (MI), heart failure, unstable angina, angina pectoris and coronary revascularization. Cardiac death occurred in 23 patients (0.6%) and non-fatal MI in 11 (0.3%). Among patients with ejection fraction (EF) of <45% and a summed difference score (SDS) of ≥2, 18.7% (2.4% for cardiac death and 0.6% for non-fatal MI) experienced total events compared with 3.9% (0.3% for cardiac death and 0.2% for non-fatal MI; P < 0.0001) of those with EF ≥ 45% and SDS < 2. Multivariate analysis identified EF, SDS, age, history of revascularization and diabetes as significant predictors of all events, while the significant predictors were age and EF for hard events. When the patients who had heart failure in the first year were followed up, 9 of 41 (22.0%) experienced cardiac death in the subsequent 3-year follow-up period. Conclusions: Myocardial ischemia defined by SDS and ventricular function were the main predictors of total events despite the relatively low incidence of hard events in this Japanese population. In patients with cardiac events in a year, closer attention should be paid to subsequent hard events particularly in patients with heart failure. © 2009 The Japanese Society of Nuclear Medicine

Frequency-dependent changes in calcium cycling and contractile activation in SERCA2a transgenic mice

Objective: This study was undertaken to investigate the mechanism of altered contractility in hearts from transgenic mice overexpressing the sarcoplasmic reticulum (SR) Ca²⁺ ATPase (SERCA2a). In particular, we sought to determine whether the reported increase in contractility is freqnency-dependent, as might be expected if attributable to changes in SR Ca²⁺ loading. Methods: Intracellular [Ca²⁺] and contractile force were measured at room temperature (22 °C) simultaneously in fura-2-loaded isometrically-contracting trabeculae dissected from the hearts of FVB/N control (n=6) or SERCA2a transgenic (n=6) mice. Results: SERCA transgenics exhibit a positive force-frequency relationship, but this was flat in age- and strain-matched controls. SERCA transgenics exhibit a sizable increase in calcium transient amplitude relative to controls, with a concomitant increase in force generation at higher frequencies of stimulation. Amplitudes of Ca²⁺ transients (transgenics: 1.56 ± 0.09 μmol/l, controls: 1.21 ± 0.14) and twitches (transgenics: 21.71 ± 0.91 mN/mm², controls: 13.74 ± 1.67) were significantly different at 2.0 Hz stimulation (P < 0.05). Conclusion: An increase in SERCA expression increases the ability of the sarcoplasmic reticulum to store calcium, such that more calcium is available to be released during each heartbeat at higher stimulation rates.Facultad de Ciencias MédicasCentro de Investigaciones Cardiovasculare

Comparison of the prognostic value of cardiac iodine-123 metaiodobenzylguanidine imaging and heart rate variability in patients with chronic heart failure A prospective study

AbstractObjectivesWe sought to prospectively compare the prognostic value of cardiac iodine-123 (I-123) metaiodobenzylguanidine (MIBG) imaging with that of heart rate variability (HRV) in patients with mild-to-moderate chronic heart failure (HF).BackgroundCardiac I-123 MIBG imaging, which reflects cardiac adrenergic nerve activity, provides prognostic information on chronic HF patients. Reduced HRV, indicating derangement in cardiac autonomic control, was also reported to be associated with a poor prognosis in chronic HF patients.MethodsAt study entry, I-123 MIBG imaging and 24-h Holter monitoring were performed in 65 chronic HF outpatients with a radionuclide left ventricular ejection fraction <40%. The cardiac MIBG heart to mediastinum ratio (H/M) and washout rate (WR) were obtained from MIBG imaging. The time and frequency domain parameters of HRV were calculated from 24-h Holter recordings.ResultsAt a mean follow-up of 34 ± 19 months, WR (p < 0.0001), H/M on the delayed image (p = 0.01), and normalized very-low-frequency power (n-VLFP) (p = 0.047) showed a significant association with the cardiac events (sudden death in 3 and hospitalization for worsening chronic HF in 10 patients) on univariate analysis. Multivariate analysis revealed that WR was the only independent predictor of cardiac events, although the predictive accuracy for the combination of abnormal WR and n-VLFP significantly increased, compared with that for abnormal WR (82% vs. 66%, p < 0.05).ConclusionsCardiac MIBG WR has a higher prognostic value than HRV parameters in patients with chronic HF. The combination of abnormal WR and n-VLFP would be useful to identify chronic HF patients at a higher risk of cardiac events

Cardiovascular events in Japanese asymptomatic patients with type 2 diabetes: a 1-year interim report of a J-ACCESS 2 investigation using myocardial perfusion imaging

金沢大学医薬保健研究域医学系Purpose Diabetic patients have a high risk for cardiovascular events. The role of myocardial perfusion imaging was investigated in asymptomatic diabetic patients to evaluate short-term prognosis in a Japanese population. Methods A total of 506 asymptomatic patients ≥50 years of age who had carotid artery maximum intima-media thickness ≥1.1 mm, urinary albumin excretion of ≥30 mg/g creatinine, with additional criteria of abdominal obesity, low HDL cholesterol, high triglyceride level, and hypertension were enrolled and followed up over a 3-year period. Gated SPECT with stress-rest protocol was performed and analyzed by summed defect scores and QGS software. One-year cardiovascular events were analyzed. Results Myocardial ischemia was observed in 17% of patients, and abnormal perfusion findings of ischemia and/or scar were observed in 32% of patients. By the end of the 1-year follow-up, 33 (6.5%) cardiovascular events occurred including 6 all-cause deaths. Patients with summed stress score (SSS) >8 had a higher incidence of either death or cardiovascular events. Event-free survival rates for SSS 0–3, 4–8, 9–13, and ≥14 were 0.96, 0.95, 0.82, and 0.76, respectively. Multivariate Cox regression analysis showed that significant variables were SSS, history of cerebrovascular accident, and electrocardiographic abnormality at rest. Conclusion The 1-year interim summary showed that cardiovascular events were significantly higher in patients with SPECT abnormality, although hard cardiac event rate was relatively low. Targeted treatment strategy is required for asymptomatic but potentially high-risk diabetic patients

Transition density of diffusion on Sierpinski gasket and extension of Flory's formula

Some problems related to the transition density u(t,x) of the diffusion on the Sierpinski gasket are considerd, based on recent rigorous results and detailed numerical calculations. The main contents are an extension of Flory's formula for the end-to-end distance exponent of self-avoiding walks on the fractal spaces, and an evidence of the oscillatory behavior of u(t,x) on the Sierpinski gasket.Comment: 11 pages, REVTEX, 2 postscript figure