Определение интервалов квазистационарности экономических систем

В работе рассмотрен вопрос определения оптимального интервала адаптации алгоритма динамического управления капиталом для нестационарного случая методами расчета показателя Херста и построения автокорреляционной функции для анализа временных рядов. Проведен анализ влияния выбора интервала адаптации на эффективность алгоритма. Из анализа полученных результатов следует, что метод расчета показателя Херста позволяет более эффективно, чем метод построения автокорреляционной функции, определить интервал стационарности модели функционирования экономической системы.Робота присвячена питанню визначення оптимального інтервалу адаптації алгоритму динамічного керування капіталом для нестаціонарного випадку за допомогою методів розрахунку показника Херста і побудови автокореляційної функції задля аналізу часових рядів. Проведено аналіз впливу вибору інтервалу адаптації на ефективність алгоритму. Порівняння результатів проведеного аналізу дозволяє стверджувати, що метод розрахунку показника Херста дозволяє більш ефективно, ніж метод побудови автокореляційної функції, визначити інтервал стаціонарності моделі функціонування економічної системи

Sex-Based Differences in the Performance of the HEART Score in Patients Presenting to the Emergency Department With Acute Chest Pain

BACKGROUND: Sex-based differences in clinical presentation, pathophysiology, and outcomes of patients with acute chest pain are increasingly being recognized, but are not implemented in guidelines and clinical prediction tools. We evaluated the performance of the HEART score in women versus men, because sex-based differences may exist among the algorithm's components: history, electrocardiogram, age, risk factors, and admission troponin level. METHODS AND RESULTS: The HEART score was retrospectively assessed in 831 women and 1084 men presenting to the emergency department with acute chest pain, assigning patients to the low-, intermediate-, or high-risk category for the occurrence of major adverse cardiac events (MACE) within 6 weeks. MACE, consisting of myocardial infarction, coronary revascularization, and all-cause death, also included events during index visit. Six-week MACE rates were 2 times lower in women than men (10.0% versus 20.8%; P<0.01). Despite similar discriminatory accuracy of the HEART score among women and men (c-statistic, 0.80 [0.75-0.84] versus 0.77 [0.74-0.81]; P=0.43), 6-week MACE rates were significantly lower in women than men across all HEART risk categories: 2.1% versus 6.5% (P<0.01) in the low-risk category, 12.7% versus 21.3% (P<0.01) in intermediate-risk category, and 53.1% versus 77.0% (P=0.02) in the high-risk category. The HEART score-adjusted risk ratio for men was 1.6 (1.3-2.0; P<0.01). CONCLUSIONS: The markedly higher 6-week MACE risk in men across all HEART risk categories should be taken into account when using the HEART score to guide clinical decision making; early discharge with a low-risk HEART score appears less safe for men than women with acute chest pain

Sex-Based Differences in the Performance of the HEART Score in Patients Presenting to the Emergency Department With Acute Chest Pain

BACKGROUND: Sex-based differences in clinical presentation, pathophysiology, and outcomes of patients with acute chest pain are increasingly being recognized, but are not implemented in guidelines and clinical prediction tools. We evaluated the performance of the HEART score in women versus men, because sex-based differences may exist among the algorithm's components: history, electrocardiogram, age, risk factors, and admission troponin level. METHODS AND RESULTS: The HEART score was retrospectively assessed in 831 women and 1084 men presenting to the emergency department with acute chest pain, assigning patients to the low-, intermediate-, or high-risk category for the occurrence of major adverse cardiac events (MACE) within 6 weeks. MACE, consisting of myocardial infarction, coronary revascularization, and all-cause death, also included events during index visit. Six-week MACE rates were 2 times lower in women than men (10.0% versus 20.8%; P<0.01). Despite similar discriminatory accuracy of the HEART score among women and men (c-statistic, 0.80 [0.75-0.84] versus 0.77 [0.74-0.81]; P=0.43), 6-week MACE rates were significantly lower in women than men across all HEART risk categories: 2.1% versus 6.5% (P<0.01) in the low-risk category, 12.7% versus 21.3% (P<0.01) in intermediate-risk category, and 53.1% versus 77.0% (P=0.02) in the high-risk category. The HEART score-adjusted risk ratio for men was 1.6 (1.3-2.0; P<0.01). CONCLUSIONS: The markedly higher 6-week MACE risk in men across all HEART risk categories should be taken into account when using the HEART score to guide clinical decision making; early discharge with a low-risk HEART score appears less safe for men than women with acute chest pain

Detection of Ischemic ST-Segment Changes Using a Novel Handheld ECG Device in a Porcine Model

Background: Portable, smartphone-sized electrocardiography (ECG) has the potential to reduce time to treatment for patients suffering acute cardiac ischemia, thereby lowering the morbidity and mortality. In the UMC Utrecht, a portable, smartphone-sized, multi-lead precordial ECG recording device (miniECG 1.0, UMC Utrecht) was developed. Objectives: The purpose of this study was to investigate the ability of the miniECG to capture ischemic ECG changes in a porcine coronary occlusion model. Methods: In 8 animals, antero-septal myocardial infarction was induced by 75-minute occlusion of the left anterior descending artery, after the first or second diagonal. MiniECG and 12-lead ECG recordings were acquired simultaneously before, during and after coronary artery occlusion and ST-segment deviation was evaluated. Results: During the complete occlusion and reperfusion period, miniECG showed large ST-segment deviation in comparison to 12-lead ECG. MiniECG ST-segment deviation was observed within 1 minute for most animals. The miniECG was positive for ischemia (ie, ST-segment deviation ≥1 mm) for 99.7% (Q1-Q3: 99.6%-99.9%) of the occlusion time, while the 12-lead was only positive for 79.8% (Q1-Q3: 81.1%-98.7%) of the time (P = 0.018). ST-segment deviation reached maxima of 10.5 mm [95% CI: 6.5-14.5 mm] vs 5.0 mm [95% CI: 2.0-8.0 mm] for the miniECG vs 12-lead ECG, respectively. Conclusions: MiniECG ST-segment deviation was observed early and was of large magnitude during 75 minutes of porcine transmural antero-septal infarction. The miniECG was positive for ischemia for the complete occlusion period. These findings demonstrate the potential of the miniECG in the detection of cardiac ischemia. Although clinical research is required, data suggests that the miniECG is a promising tool for the detection of cardiac ischemia.</p

Sensitivity, specificity, predictive values and AUCs of hs-cTnT, myoglobin and 5 novel biomarkers in patients with symptom onset within 3 hours.

<p>Values are given as percentage or number (95%CI)</p><p>Abbreviations: hs-cTnT, high-sensitive cardiac troponin; PlGF, placental growth factor; sFlt-1, soluble Fms-like tyrosine kinase-1; NT-proBNP, N-terminal prohormone B-type Natriuretic Peptide; GDF-15, growth differentiation factor-15; PPV, positive predictive value; NPV, negative predictive value; AUC, area under the receiver operating curve (ROC).</p><p>Sensitivity, specificity, predictive values and AUCs of hs-cTnT, myoglobin and 5 novel biomarkers in patients with symptom onset within 3 hours.</p

Median biomarker concentrations and inter quartile ranges stratified by ACS status.

<p>Values are given as median (Inter Quartile Range); p-value calculated with Mann-Whitney <i>U</i>-test</p><p>Abbreviations: hs-cTnT, high-sensitive cardiac troponin; PlGF, placental growth factor; sFlt-1, soluble Fms-like tyrosine kinase-1; NT-proBNP, N-terminal prohormone B-type Natriuretic Peptide; GDF-15, growth differentiation factor-15.</p><p>Median biomarker concentrations and inter quartile ranges stratified by ACS status.</p

Receiver-operating-characteristic curves of the clinical model with the various biomarkers, high sensitive cardiac troponin T (hs-cTnT), placental growth factor (PlGF), fms-like tyrosine kinase-1 (sFlt-1), myoglobin, N-terminal prohormone B-type Natriuretic Peptide (NT-proBNP), growth differentiation factor-15 (GDF-15) and copeptin.

<p>(The ROC curve shown is from the first imputation set)</p

Flow chart of patient selection from all patients with symptoms suggestive of ACS to enrolled patients.

<p>Flow chart of patient selection from all patients with symptoms suggestive of ACS to enrolled patients.</p