[Neurally-mediated syncope and occupational accidents: prevention strategies and case report]. / Sincope neuromediata e infortuni sul lavoro: strategie preventive e considerazioni su un caso clinico.

A bus driver came to our observation after an occupational traffic accident due to a syncopal event. The positive result of the tilt testing demonstrated the neurally-mediated nature of the syncope. The accident involved approximately 40 people (all the bus passengers), fortunately without severe injuries or deaths. The described episode indicates the need for a procedural algorithm, commonly approved, applicable in the field of prevention, for those occupational categories with severe accident risk. Indeed, the possibility exists to identify at least a part of the subjects predisposed to neurally-mediated syncope. Fundamental steps for such screening are history taking (looking for previous events, familiarity), the physical examination (useful, for example, to exclude orthostatic hypotension or carotid sinus syncope), and, in particular, the tilt testing, a diagnostic investigation recommended for all the workers who have had a previous syncope and are at high occupational accident risk. Moreover, the reported case recalls the need to strengthen the collaboration between the cardiologist and the occupational health physician.

Test to determine the Markov order of a time series.

The Markov order of a time series is an important measure of the "memory" of a process, and its knowledge is fundamental for the correct simulation of the characteristics of the process. For this reason, several techniques have been proposed in the past for its estimation. However, most of this methods are rather complex, and often can be applied only in the case of Markov chains. Here we propose a simple and robust test to evaluate the Markov order of a time series. Only the first-order moment of the conditional probability density function characterizing the process is used to evaluate the memory of the process itself. This measure is called the "expected value Markov (EVM) order." We show that there is good agreement between the EVM order and the known Markov order of some synthetic time series.

Langevin equations from time series.

We discuss the link between the approach to obtain the drift and diffusion of one-dimensional Langevin equations from time series, and Pope and Ching's relationship for stationary signals. The two approaches are based on different interpretations of conditional averages of the time derivatives of the time series at given levels. The analysis provides a useful indication for the correct application of Pope and Ching's relationship to obtain stochastic differential equations from time series and shows its validity, in a generalized sense, for nondifferentiable processes originating from Langevin equations.

[Primary angioplasty in acute inferior myocardial infarct with anterior ST-segment depression: the long-term follow-up]. / Angioplastica primaria nell'infarto miocardico acuto inferiore con sottoslivellamento anteriore del tratto ST: follow-up a lungo termine.

BACKGROUND: Concomitant anterior ST-segment depression is a marker of severe prognosis in inferior myocardial infarction. PATIENTS AND METHODS: Prospective observational study in patients with inferior acute myocardial infarction and ST-segment depression > or = 4 mm in the anterior leads, who were treated with primary angioplasty. Angiography was performed at hospital discharge and at six months, and a clinical follow-up was obtained at one year after the infarction. RESULTS: Sixty-three patients were included in the study. Pre-hospital and in-hospital delay were 147 +/- 70 minutes (20-355) and 54 +/- 11 minutes (18-80), respectively. Angioplasty was successful in all patients and 48 stents were implanted in 36 patients (57%). Angiography was performed at hospital discharge in 55 patients (87%) and showed a TIMI grade 3 coronary flow in the infarct-related artery in all cases. The left ventricular ejection fraction was 0.55 +/- 0.09 (0.4-0.8). One patient (1.6%) died before discharge, two (3.2%) had ischemic complications (one had non-fatal reinfarction, another had recurrent angina at rest), and three (4.9%) had local vascular complications. At the six-month follow-up, none of the patients had died. One had suffered reinfarction (1.6%) and another had been readmitted for recurrence of angina at rest (1.6%); none had symptoms of stable angina. The ejection fraction was 0.56 +/- 0.12 and eight patients (14%) showed angiographic restenosis. At twelve months, two patients had died (1.6%) and five (8%) had required readmission to hospital. CONCLUSIONS: Primary angioplasty yielded favorable results in this group of patients. Our data confirm the efficacy of primary angioplasty for the treatment of acute myocardial infarction, with a low rate of clinical (3.2%) and angiographic (14%) restenosis at six months, and a high rate (87%) of event-free survival at one year follow-up.

Early aggressive treatment of unstable angina without on-site cardiac surgical facilities: a prospective study of acute and long-term outcome.

BACKGROUND: The early invasive diagnostic approach with extensive use of myocardial revascularization in patients with unstable angina is a matter of debate. Both the advantages of this strategy and the choice of the best candidates are controversial. The widespread applicability of this approach in Italian hospitals is also questionable, due to limited availability of facilities for interventional cardiology. METHODS: A prospective, observational study was done on a cohort of consecutive patients, who were admitted with a diagnosis of unstable angina and treated with an early aggressive approach at a center with interventional cardiology facilities without cardiac surgery. The aim of the study was to evaluate both the immediate and long-term clinical outcome of patients and the efficiency of our therapeutic approach. RESULTS: Two-hundred and two patients were enrolled and 85% were in Braunwald class III. Coronary angiography was performed in 171 patients (85%) at 2.1 +/- 2.4 days after admission: it showed one-, two- and three-vessel disease in 40, 29 and 22% of cases, respectively; 9% of patients had no severe coronary lesion. Left ventricular ejection fraction was 0.58 +/- 0.13. Medical treatment, coronary by-pass surgery and percutaneous myocardial revascularization were chosen in 36, 24 and 40% of cases, respectively. Coronary angioplasty was performed in our center in 58 (73%) of 80 patients at 6.8 +/- 5.6 days after admission and stents were used in 42 cases (74%). Overall hospital stay was 10.4 +/- 4 days. Cumulated adverse events (death and non-fatal myocardial infarction) occurred in 2.5 and 7% of patients during the initial admission and in the following year, respectively. CONCLUSIONS: An early aggressive approach to patients with unstable angina is feasible in a hospital with interventional cardiology in the absence of cardiac surgical facilities. The immediate favorable clinical results of this strategy in an intermediate-risk cohort seem to persist at one-year follow-up.

Prevalence of late potentials after myocardial infarction treated with systemic thrombolysis or primary percutaneous transluminal coronary angioplasty.

BACKGROUND: The presence of late potentials (LP) after myocardial infarction (MI) is related to an occluded infarct-related coronary artery (IRA). However, the effects of the signal-averaged electrocardiogram (SAECG) of systemic thrombolysis are contradicting. Reperfusion in the IRA is more frequently observed after primary percutaneous transluminal coronary angioplasty (PTCA) than after systemic thrombolysis. The aim of this prospective study was to compare the prevalence of LP in survivors of acute MI treated with either systemic thrombolysis or primary PTCA. METHODS: Between October 1994 and January 1997, 134 patients (pts) with acute MI were treated with reperfusion therapy within 12 hours of the onset of symptoms: seventy-four pts received systemic thrombolysis and 60 underwent primary PTCA. All pts (mean age 61 +/- 10 years, 120 males) had a control coronary angiography 9 +/- 5 and 10 +/- 4 days after acute MI, respectively. The recorded signals were amplified, averaged and filtered with bi-directional Butterworth filtering (band-pass filter range of 40-250 Hz). LPs were defined as the presence of 2 or 3 of the following criteria: filtered duration of the QRS complex > 114 ms, root mean square voltage of signals in the last 40 ms of the QRS < or = 20 mV and duration of the low amplitude signals > 38 ms. RESULTS: The two groups of pts did not differ significantly with respect to age, gender, presence of either diabetes or hypertension, site of MI, previous MI, Killip class, time to treatment, peak CK-MB level, incidence of reinfarction, extent of coronary artery disease and left ventricular ejection fraction. One hundred pts (75%) had patency (TIMI 3 grade flow) of the IRA at control coronary angiography. Twenty-seven pts (20%) had LP: 16 pts (22%) among those treated with systemic thrombolysis and 11 pts (18%) among those treated with primary PTCA (p = ns). Pts treated with primary PTCA had higher patency rates [95% (57/60) vs 58% (43/74); p = 0.00002] and less severe residual stenosis (19 +/- 15% vs 72 +/- 18%; p = 0.0001) in the IRA. LP were found in 15 pts (15%) with TIMI 3 grade flow and in 12 pts (35%) with TIMI 0-2 grade flow (p = 0.017). By multivariate analysis, including 18 clinical and electrocardiographic variables, an occluded IRA was the only independent predictor of the development of LP (Wald chi 2: 6.1453; p = 0.0132). CONCLUSION: Results of this prospective study suggest that primary PTCA alone does not reduce the prevalence of LP when compared to systemic thrombolysis. Only the patency of the IRA, as determined before the hospital discharge, affected the development of LP after acute MI.

[Effects on high resolution electrocardiogram of coronary angioplasty in acute myocardial infarct]. / Effetti sull'elettrocardiogramma ad alta risoluzione dell'angioplastica coronarica nell'infarto miocardico acuto.

BACKGROUND: The lower prevalence of ventricular late potentials (LPs) in signal-averaged electrocardiograms (SAECG) observed in patients (pts) treated with systemic thrombolysis, as compared with SAECGs in conventionally treated pts, has been attributed to the patency of the infarct-related artery. Mechanical reperfusion, achieved by means of either primary or rescue percutaneous transluminal coronary angioplasty (PTCA), is associated with higher permeability rates and reduced residual stenosis in the infarct-related artery, when compared to systemic thrombolysis. The aim of this retrospective study was to assess the prevalence of LPs in pts recovering from a first high-risk acute myocardial infarction (AMI) treated with primary or rescue PTCA. METHODS: Fifty-nine pts (48 pts with clinical signs or electrocardiographic evidence of high-risk AMI or in whom systemic thrombolysis was inadvisable, and 11 pts in whom systemic thrombolysis failed) underwent emergency PTCA within 10 hours of the onset of symptoms. All pts (mean age 61 +/- 9 years, 48 M) were monitored via coronary angiography 9 +/- 4 days after AMI. The SAECG was obtained 10 +/- 4 days after AMI. LPs were defined as the presence of 2 or 3 of the following criteria: filtered duration of the QRS complex > 114 ms, duration of the low amplitude signals > 38 ms and mean square-root voltage of signals in the last 40 ms of the QRS < or = 20 microV. RESULTS: Primary and rescue PTCA were performed 3 +/- 1.7 and 6.3 +/- 2 hours after AMI, respectively (p = 0.000). Fifty-six pts (95%) had patency (TIMI 3 grade flow) of the infarct-related artery (mean residual stenosis: 18.3 +/- 14.2%) confirmed by control coronary angiography, while the infarct-related artery was occluded in three pts. Sixteen out of 59 pts (27%) had LPs: 14/56 (25%) with TIMI 3 grade flow and 2/3 (67%) with TIMI 0 grade flow. Pts with and without LPs were comparable for age, sex, infarct location, Killip Class, mean peak CK-MB, time to control coronary angiography, time to SAECG, left ventricular ejection fraction, presence of multivessel disease, infarct-related artery and mean residual stenosis in infarct-related artery. LPs were observed more frequently after rescue PTCA than after primary PTCA (64 vs 19%; p = 0.005). Time to treatment was significantly longer in pts with LPs than in those without (4.9 +/- 2.6 vs 3.2 +/- 1.7 hours; p = 0.025). Multivariate analysis indicated that the type of PTCA (primary vs rescue PTCA) was the only independent predictor for the development of LPs. CONCLUSION: In this study, the prevalence of LPs in pts with patency of the infarct-related artery after primary or rescue PTCA was surprisingly high. Delay to treatment and type of PTCA affected the presence of LPs. The association between infarct-related artery status and prevalence of LPs has not been analyzed, due to the low number of pts with coronary artery occlusion in the control coronary angiography.

Time domain signal-averaged electrocardiogram in predicting arrhythmic events after myocardial infarction: role of the duration of the filtered QRS complex.

Several studies showed that time domain analysis of the signal-averaged ECG may identify groups of patients with low and high risk for arrhythmic events after myocardial infarction (MI). However, the signal averaging methods were not uniform and the definition of abnormal signal-averaged ECG was empiric. To identify the best quantitative signal-averaged variable in predicting arrhythmic events (sustained ventricular tachycardia, ventricular fibrillation and witnessed, instantaneous death) 262 patients surviving acute MI were prospectively evaluated. Twelve clinical variables, left ventricular ejection fraction (LVEF), complex ventricular arrhythmias (CVA) on Holter monitoring and three conventional signal-averaged variables (either at 25-250 or 40-250 Hz) were entered in a Cox proportional hazards regression model. During a mean follow-up of 20.3 +/- 13.7 months 16 (6.1%) patients had arrhythmic events. All six signal-averaged variables were independent predictors of arrhythmic events and the filtered QRS duration (fQRSD) > or = 120 ms at 40 Hz high pass filtering resulted the most predictive. In a regression analysis, including the best signal-averaged variable, LVEF and CVA, only fQRSD > or = 120 ms at 40 Hz and LVEF independently predicted arrhythmic events. Sensitivity, specificity, positive predictive value and odds ratio for fQRSD > or = 120 ms at 40 Hz were 63, 90, 29 and 11%, respectively, and for the combination of fQRSD > or = 120 ms at 40 Hz and LVEF < 40%, were 73, 95, 47 and 39%, respectively. In conclusion, the fQRSD > or = 120 ms at 40 Hz best predicts arrhythmic events in the post-infarction period. The combination of signal-averaged ECG and LVEF is recommended to stratify patients at risk of arrhythmic events after MI.

[Quality assurance and cost control in invasive and interventional cardiology]. / Quality assurance e controllo dei costi in cardiologia invasiva ed interventistica.

We report our experience of Quality Assurance in a Cardiac Catheterization Laboratory of the National Health Service. An attempt was made to apply these criteria to the medical activities as well as to the management and economic aspects of our work. Limits and perspectives of this experience are discussed as a contribution to ongoing debate among cardiologists and public health Authorities.

Fortification of precooked maize flour with coarse defatted maize germ.

The possibility of improving the dietary value of precooked maize flour through fortification with 11% coarse defatted maize germ was investigated. The results of tests in humans presented here show that the total iron absorption from the fortified preparation is similar to that from the precooked maize alone, but with the advantage of being richer in several nutrients: protein (25%), zinc (61%), potassium (47%) and magnesium (112%), as well as fiber (34%). Fortification lowers (by 20%) rather than raises the cost of the flour, and may be an important contribution to the diet of those populations where maize bread is a major component of the diet.

[Soy and corn flour precooked with microwaves and its use in the preparation of arepas]. / Precocción de harina de soya y maíz por microonda, y su uso en la preparación de arepas.

Unhusked corn and soy grits were used as raw material, with a particle size ranging between 10 and 20 mesh (ASTM). The results obtained in this study reveal that microwave heating is effective in destroying the antinutritional factors present in soybeans. The trypsin inhibitor activity, in effect, was reduced to a 76% inactivation. The hemagglutinating titer was labile to the heating process, showing values of +8 to +3 for the full-fat soy flour and precooked soy flour, respectively. The quality of soy protein was measured by the protein efficiency ratio (PER) showing values of 2.63 for the precooked soy flour, and 2.46 to 2.21 for the precooked corn:soy blends (70:30 and 50:50). These uncooked blends present values of 1.17 and 1.04. The enriched corn:soy flour had a PER value of 1.60, in comparison to casein (PER = 2.90). The microwave heating improved the digestibility of the soy flour and blends. There were no significant differences (P less than or equal to 0.05) in relation to the functionality of the precooked flour and mixtures. The results obtained revealed that the applied process markedly improve the functional properties and nutritional value of the enriched flour, and of the "arepas" prepared from them.

Precocción de harine de soya maíz por microonda, y su uso en la preparación de arepas / Precooked of soy flour and corn by the microwave and its use in the preparation of arepas

Se utilizó sémola de maíz y soya descascarada, con una granulometría entre 10 y 20 mesh (ASTM). El proceso de calentamiento por microonda es efectivo para destruir los factoes antinutricionales de la soya. La actividad inhibidora de la tripsina se redujo en un 76%. El título hemaglutinante resultó ser termolábil, obteniéndose valores de +8 a +3 para la soya integral y precocida, respectivamente. La calidad de la proteína medida por el índice de eficiencia proteínica (PER) dio valores de 2.63 para la harina de soya precocida, y de 2.46 y 2.21 para las mexclas maíz: soya (70:30 y 50:50). Estas mezclas crudas tenían valores de 1.17 y 1.04 respectivamente. La harina de maíz enriquecida con 10% de soya precocida presentó un valor de PER de 1.60; con soya precocida los valores de PER no difirieron (P < ou = 0.05) de los valores de PER de la caseína. La soya y mezclas maíz : soya acusaron una lata digestibilidad que no difiere significativamente (P < ou = 0.05) en relación a los índices de absorción de agua, solubilidad en agua, pegajosidad, separación de agua y expansibilidad de la harina y las diferentes mezxlas. Los resultados revelaron que el proceso de calentamiento en microondas mejora notablemente las propiedades funcionales y nutricionales de la harina enriquecida y de las arepas elaboradas con ésta