Infective endocarditis in octogenarians. A retrospective study in a single, high-volume surgical centre

BACKGROUND

Infective endocarditis (IE) is a severe disease associated with high morbidity and mortality. Little is known about the best management of elderly patients with IE. In these patients, surgery may be challenging. Our study aimed to describe IE's features in octogenarians and to identify the independent predictors of mortality, focusing on the prognostic impact of disability.

METHODS

We retrospectively analyzed 551 consecutive patients admitted to a single surgical centre with a definite diagnosis of non-device-related infective endocarditis; of these, 97 (17.6%) were older than 80 years.

RESULTS

In patients under eighty, males were mostly involved with a sex ratio exceeding 2:1. This ratio was inverted in older people, where the female gender represented 53.6% of the total. Enterococci (29.8 vs. 17.4%, p = 0.005) were significantly more frequent than in younger people. Comorbidities were more frequent in elderly patients; consequently, EuroSCORE II was higher (median ± IQR 16.4 ± 21.1 vs. 5.0 ± 10.3, p = 0.001). In octogenarians, IE was more frequently left-sided (97.9 vs. 89.8%, p = 0.011). Octogenarians were more often excluded from surgery despite indication (23.7 vs. 8.1%, p = 0.001) and had higher three-year mortality (45.3 vs. 30.6%, p = 0.005) than younger patients. In elderly patients, age did not independently predict mortality, while exclusion from surgery and a high grade of disability did.

CONCLUSIONS

Octogenarians with IE have specific clinical and microbiological characteristics. Older patients are more often excluded from surgery, and the overall prognosis is poor. Age per se should not be a reason to deny surgery, while disability predicts futility.

Impact of cardiac surgery on left-sided infective endocarditis with intermediate-length vegetations

OBJECTIVE

The best strategy to manage patients with left-sided infective endocarditis (IE) and intermediate-length vegetations (10-15 mm) remains uncertain. We aimed to evaluate the role of surgery in patients with intermediate-length vegetations and no other European Society of Cardiology guidelines-approved surgical indication.

METHODS

We retrospectively enrolled 638 consecutive patients admitted to three academic centres (Amiens, Marseille and Florence University Hospitals) between 2012 and 2022 for left-sided definite IE (native or prosthetic) with intermediate-length vegetations (10-15 mm). We compared four clinical groups: medically (n=50) or surgically (n=345) treated complicated IE, medically (n=194) or surgically (n=49) treated uncomplicated IE.

RESULTS

Mean age was 67±14 years. Women were 182 (28.6%). The rate of embolic events on admission was 40% in medically treated and 61% in surgically treated complicated IE, 31% in medically treated and 26% in surgically treated uncomplicated IE. The analysis of all-cause mortality showed the lowest 5-year survival rate for medically treated complicated IE (53.7%). We found a similar 5-year survival rate for surgically treated complicated IE (71.4%) and medically treated uncomplicated IE (68.4%). The highest 5-year survival rate was observed in surgically treated uncomplicated IE group (82.4%, log-rank p<0.001). The analysis of the propensity score-matched cohort estimated an HR of 0.23 for uncomplicated IE treated surgically compared with medical therapy (p=0.005, 95% CI: 0.079 to 0.656).

CONCLUSIONS

Our results suggest that surgery is associated with lower all-cause mortality than medical therapy in patients with uncomplicated left-sided IE with intermediate-length vegetations even in the absence of other guideline-based indications.

Prognostic impact of cerebral embolism in patients with active infective endocarditis and therapeutic strategies. A retrospective real world study in a surgical centre

Purpose

Infective endocarditis still has high mortality and invalidating complications, such as cerebral embolism. The best strategies to prevent and to manage neurologic complications remain uncertain. This study aimed to identify predictors of septic cerebral embolism and to evaluate the role of surgery in these patients, in a real-world surgical center.

Methods

We retrospectively analyzed 551 consecutive patients admitted to our department with a definite diagnosis of non-device-related infective endocarditis; of these, 126 (23%) presented a neurologic complication.

Results

Cerebral embolism was significantly more frequent in patients with large vegetations (p=0.001), mitral valve infection (p=0.001), and Staphylococcus aureus infection (p=0.025). At multivariable analysis, only vegetation length was an independent predictor of cerebral embolism (HR 1.057, 95% CI 1.025–1.091, p 0.001), with a best predictive threshold of 10 mm at ROC curve analysis (AUC 0.54, p=0.001). Patients with neurologic complications were more often excluded from surgery despite an indication to it (16% vs 8%, p=0.001). If eligible, they were treated within two weeks from diagnosis in similar proportion as patients without cerebral embolism with similar survival rate. Predictors of mortality were hemorrhagic lesions (p=0.018), a GCS&lt;14 (p=0.001) or a severe degree of disability (p=0.001) at presentation. The latter was the only independent predictor of mortality at multivariable analysis (HR 2.3, 95% CI 1.43–3.80, p=0.001).

Conclusions

The present study highlights the prognostic value of clinical functional presentation and the safety of cardiac surgery, when feasible, in patients with septic cerebral embolism.

Funding Acknowledgement

Type of funding sources: None.

Echocardiographic Abnormalities in Adults With Anorexia Nervosa

Anorexia nervosa (AN) is a psychiatric disorder that may lead to cardiac complications. The objective of this study was to evaluate global and regional longitudinal strain changes in patients affected by AN as an early marker of myocardial damage. We prospectively enrolled 48 consecutive patients with AN and 44 age-matched and gender-matched healthy controls. In all subjects, we performed echocardiography, including global longitudinal strain (GLS) measurement. A subset of 33 patients with AN had further echocardiographic examinations during the follow-up. Compared with healthy controls, patients with AN had a greater prevalence of pericardial effusion (9 of 48 vs 0 of 44, p = 0.003), a smaller left ventricular mass (63 ± 15 vs 99 ± 30 g, p < 0.001), a lower absolute value of GLS (-18.9 ± 2.8 vs -20.2 ± 1.8%, p = 0.010) and of basal LS (-15.4 ± 6.0 vs -19.4 ± 2.6%, p < 0.001). The bull's eye mapping showed a plot pattern with blue basal areas in 18 of 48 patients with AN versus 1 of 44 controls (p < 0.001). During the follow-up, of 13 patients with blue areas in the first bull's eye mapping, 11 recovered completely, and of 20 patients with a red bull's eye at the first examination, none presented blue areas at the second one. In conclusion, GLS is significantly altered in patients with AN, and a basal blue pattern on bull's eye mapping identifies more severe cases. These changes seem to be reversible.

Impact of septic cerebral embolism on prognosis and therapeutic strategies of infective endocarditis: a retrospective study in a surgical centre

Background

Infective endocarditis still has high mortality and invalidating complications, such as cerebral embolism. The best strategies to prevent and manage neurologic complications remain uncertain. This study aimed to identify predictors of cerebral septic embolism and evaluate the role of surgery in these patients in a real-world surgical centre.

Methods

We retrospectively analyzed 551 consecutive patients admitted to our department with a definite diagnosis of non-device-related infective endocarditis; of these, 126 (23%) presented a neurologic complication.

Results

Cerebral embolism was significantly more frequent in patients with large vegetations (p = 0.004), mitral valve infection (p = 0.001), and Staphylococcus aureus infection (p = 0.025). At multivariable analysis, only vegetation length was an independent predictor of cerebral embolism (HR per unit 1.057, 95% CI 1.025–1.091, p 0.001), with a best predictive threshold of 10 mm at ROC curve analysis (AUC 0.54, p = 0.001). Patients with neurologic complications were more often excluded from surgery despite an indication to it (16% vs 8%, p = 0.001). If eligible, they were treated within two weeks from diagnosis in similar proportions as patients without cerebral embolism with a similar survival rate. Predictors of mortality were hemorrhagic lesions (p = 0.018), a GCS < 14 (p = 0.001) or a severe degree of disability (p = 0.001) at presentation. The latter was the only independent predictor of mortality at multivariable analysis (HR 2.3, 95% CI 1.43–3.80, p = 0.001).

Conclusions

The present study highlights the prognostic value of functional presentation and the safety of cardiac surgery, when feasible, in patients with cerebral septic embolism.

Paper-based genetic assays with bioconjugated gold nanorods and an automated readout pipeline

Paper-based biosensors featuring immunoconjugated gold nanoparticles have gained extraordinary momentum in recent times as the platform of choice in key cases of field applications, including the so-called rapid antigen tests for SARS-CoV-2. Here, we propose a revision of this format, one that may leverage on the most recent advances in materials science and data processing. In particular, we target an amplifiable DNA rather than a protein analyte, and we replace gold nanospheres with anisotropic nanorods, which are intrinsically brighter by a factor of ~ 10, and multiplexable. By comparison with a gold-standard method for dot-blot readout with digoxigenin, we show that gold nanorods entail much faster and easier processing, at the cost of a higher limit of detection (from below 1 to 10 ppm in the case of plasmid DNA containing a target transgene, in our current setup). In addition, we test a complete workflow to acquire and process photographs of dot-blot membranes with custom-made hardware and regression tools, as a strategy to gain more analytical sensitivity and potential for quantification. A leave-one-out approach for training and validation with as few as 36 sample instances already improves the limit of detection reached by the naked eye by a factor around 2. Taken together, we conjecture that the synergistic combination of new materials and innovative tools for data processing may bring the analytical sensitivity of paper-based biosensors to approach the level of lab-grade molecular tests.

Infective endocarditis in intravenous drug abusers: clinical challenges emerging from a single-centre experience

Background

Intravenous drug abuse (IDA) is a known risk factor for infective endocarditis (IE) and is associated with frequent relapses, but its prognostic impact is still debated. The potential futility of surgery in this population is a further issue under discussion. We aimed to describe the clinical characteristics, the therapeutic strategy, and the prognosis associated with IDA in IE.

Methods

We retrospectively analysed 440 patients admitted to a single surgical centre for definite active IE from January 2012 to December 2020.

Results

Patients reporting IDA (N = 54; 12.2%) were significantly younger (p < 0.001) and presented fewer comorbidities (p < 0.001). IDA was associated with a higher proportion of relapses (27.8 vs. 3.3%, p < 0.001) and, at multivariable analysis, was an independent predictor of long-term mortality (HR 2.3, 95%CI 1.1–4.7, p = 0.015). We did not register multiple relapses in non-IDA patients. Among IDA patients, we observed 1 relapse after discharge in 9 patients, 2 relapses in 5 patients and 3 relapses in 1 patient. In IDA patients, neither clinical and laboratory variables nor the occurrence of even multiple relapses emerged as indicators of an adverse risk–benefit ratio of surgery in patients with surgical indication.

Conclusions

IE secondary to IDA affects younger patients than those with IE not associated with IDA. Probably due to this difference, IE secondary to IDA is not associated with significantly higher mortality, whereas the negative, long-term prognostic impact of IDA emerges in multivariate analysis. Considering the good prognosis of patients with uncomplicated IE treated medically, surgery should be reserved to patients with a strict- guidelines-based indication. However, since there are no clear predictors of an unfavourable risk–benefit ratio of surgery in patients with surgical indication, all patients with a complicated IE should be operated, irrespective of a history of IDA.

Endocarditis with spondylodiscitis: clinical characteristics and prognosis

Background

The association of infective endocarditis (IE) with spondylodiscitis (SD) was first reported in 1965, but few data are available about this issue. This study aimed to evaluate the prevalence of SD in patients with IE, and to determine the clinical features and the prognostic impact of this association.

Methods

We retrospectively analysed 363 consecutive patients admitted to our Department with non-device-related IE. Radiologically confirmed SD was revealed in 29 patients (8%). Long-term follow-up (average: 3 years) was obtained by structured telephone interviews; in 95 cases (13 of whom had been affected by SD), follow-up echocardiographic evaluation was also available.

Results

At univariable analysis, the combination of IE with SD was associated with male gender (p = 0.017), diabetes (p = 0.028), drug abuse (p = 0.009), Streptococcus Viridans (p = 0.009) and Enterococcus (p = 0.015) infections. At multivariable analysis, all these factors independently correlated with presence of SD in patients with IE. Mortality was similar in patients with and without SD. IE relapses at 3 years were associated with the presence of SD (p = 0.003), Staphylococcus aureus infection (p < 0.001), and drug abuse (p < 0.001) but, at multivariable analysis, only drug abuse was an independent predictor of IE relapses (p < 0.001; HR 6.8, 95% CI 1.6–29). At echocardiographic follow-up, SD was not associated with worsening left ventricular systolic function or valvular dysfunction.

Conclusions

The association of IE with SD is not rare. Hence, patients with IE should be screened for metastatic infection of the vertebral column, especially if they have risk factors for it. However, SD does not appear to worsen the prognosis of patients with IE, either in-hospital or long-term.

Predictors of mortality and adverse events in patients with infective endocarditis: a retrospective real world study in a surgical centre

Purpose

Mortality in infective endocarditis (IE) is still high, and the long term prognosis remains uncertain. This study aimed to identify predictors of long-term mortality for any cause, adverse event rate, relapse rate, valvular and ventricular dysfunction at follow-up, in a real-world surgical centre.

Methods

We retrospectively analyzed 363 consecutive episodes of IE (123 women, 34%) admitted to our department with a definite diagnosis of non-device-related IE. Median follow-up duration was 2.9 years. Primary endpoints were predictors of mortality, recurrent endocarditis, and major non-fatal adverse events (hospitalization for any cardiovascular cause, pace-maker implantation, new onset of atrial fibrillation, sternal dehiscence), and ventricular and valvular dysfunction at follow-up.

Results

Multivariate analysis independent predictors of mortality showed age (HR per unit 1.031, p < 0.003), drug abuse (HR 3.5, p < 0.002), EUROSCORE II (HR per unit 1.017, p < 0.0006) and double valve infection (HR 2.3, p < 0.001) to be independent predictors of mortality, while streptococcal infection remained associated with a better prognosis (HR 0.5, p < 0.04). Major non-fatal adverse events were associated with age (HR 1.4, p < 0.022). New episodes of infection were correlated with S aureus infection (HR 4.8, p < 0.001), right-sided endocarditis (HR 7.4, p < 0.001), spondylodiscitis (HR 6.8, p < 0.004) and intravenous drug abuse (HR 10.3, p < 0.001). After multivariate analysis, only drug abuse was an independent predictor of new episodes of endocarditis (HR 8.5, p < 0.001). Echocardiographic follow-up, available in 95 cases, showed a worsening of left ventricular systolic function (p < 0.007); severe valvular dysfunction at follow-up was reported only in 4 patients, all of them had mitral IE (p < 0.03).

Conclusions

The present study highlights some clinical, readily available factors that can be useful to stratify the prognosis of patients with IE.

Feasibility and outcome of mitral valve repair in patients with infective endocarditis

Background

Valve repair is the treatment of choice for native mitral valve regurgitation. The feasibility of repair when the defect is caused by acute infective endocarditis (IE) is debated. This study aims to compare the outcome of repair and replacement procedures, to report the rate of repair in a single surgical center, and to review the literature on this topic.

Results

We retrospectively analyzed 108 patients with native mitral IE, potentially eligible for surgical repair. Of these 108, 90 (83%) underwent surgery, and 18 were treated conservatively. Among the 90 surgical patients, 57 (63%) underwent valve replacement and 33 valve repair (37%). The mean follow-up duration was 3 years. The two primary endpoints were mortality and freedom from recurrent endocarditis. Secondary endpoints were the post-operative incidence of major adverse events (hospitalization for any cause, pacemaker implantation, new onset of atrial fibrillation, sternal dehiscence), left ventricular systolic function (LVSF), and valvular function at 1-year echocardiographic follow-up. All-cause mortality was lower for valve repair, although not significantly (p = 0.86), as well as nonfatal adverse events (p = 0.92) and relapse rate (p = 0.20) at 3 years. We did not find differences between the two groups at echocardiographic follow-up, neither for left ventricular systolic function (p = 0.22), nor for valvular continence (p = 0.28).

Conclusions

In our experience, the mid-term outcome of repair in IE is comparable to valve replacement and should be considered whenever possible, as in degenerative valve disease. The review of the literature supports this strategy.

Embolic risk stratification and prognostic impact of early surgery in left-sided infective endocarditis

BACKGROUND

In patients with left-sided infective endocarditis (IE) and heart failure associated with large vegetations, early surgery prevents embolic events. However, optimal timing of surgery for other indications is still unresolved particularly when the presence of large vegetations represents the sole indication.

METHODS

We retrospectively analyzed 308 consecutive patients admitted to our department with definite left-sided IE. Of these patients, 243 (79%) underwent cardiac surgery (complicated IE), 34 patients with uncomplicated IE received medical treatment, 24 were not operated due to prohibitive general conditions and 7 refused surgery. Long-term follow-up was obtained by structured telephone interviews.

RESULTS

During the 6-year follow-up (average 121.8 weeks ± 76), patients not operated because of general conditions or refusal had the worst prognosis, while outcome in operated patients for complicated IE was comparable to that of uncomplicated IE treated medically. Early (<2 weeks from diagnosis) surgery was associated with better survival compared to delayed surgery (HR 0.58, p = 0.23). Embolic events were detected at admission in 38% of cases; Staphylococcus Aureus etiology and vegetation size were independently associated with embolism (OR 2.4, p = 0.01; OR 1, p=0.008 respectively).

CONCLUSIONS

Compared to uncomplicated medically-treated patients, complicated IE showed comparable survival when managed aggressively by surgical intervention, whereas a conservative approach was associated with an adverse prognosis. Staphylococcus Aureus infection and vegetation size were independent predictors of systemic embolism. Our data support aggressive surgical management of complicated IE patients and highlight the importance of etiological characterization in clinical decision-making.

Comprehensive Analysis of Radiomic Datasets by RadAR

Quantitative analysis of biomedical images, referred to as radiomics, is emerging as a promising approach to facilitate clinical decisions and improve patient stratification. The typical radiomic workflow includes image acquisition, segmentation, feature extraction, and analysis of high-dimensional datasets. While procedures for primary radiomic analyses have been established in recent years, processing the resulting radiomic datasets remains a challenge due to the lack of specific tools for doing so. Here we present RadAR (Radiomics Analysis with R), a new software to perform comprehensive analysis of radiomic features. RadAR allows users to process radiomic datasets in their entirety, from data import to feature processing and visualization, and implements multiple statistical methods for analysis of these data. We used RadAR to analyze the radiomic profiles of more than 850 patients with cancer from publicly available datasets and showed that it was able to recapitulate expected results. These results demonstrate RadAR as a reliable and valuable tool for the radiomics community. SIGNIFICANCE: A new computational tool performs comprehensive analysis of high-dimensional radiomic datasets, recapitulating expected results in the analysis of radiomic profiles of >850 patients with cancer from independent datasets.

Occupational exposure in MR facilities due to movements in the static magnetic field

PURPOSE

The exposure of operators moving in the static field of magnetic resonance (MR) facilities was assessed through measurements of the magnetic flux density, which is experienced as variable in time because of the movement. Collected data were processed to allow the comparison with most recent and authoritative safety standards.

METHODS

Measurements of the experienced magnetic flux density B were performed using a probe worn by volunteers moving in MR environments. A total of 55 datasets were acquired nearby a 1.5 T, 3 T, and 7 T whole body scanners. Three different metrics were applied: the maximum intensity of B, to be compared with 2013/35/EU Directive exposure limit values for static fields; the maximum variation of the vector B on every 3s-interval, for comparison with the ICNIRP-2014 basic restriction aimed at preventing vertigo effects; two weighted-peak indices (for "sensory" and "health" effects: SENS-WP, HLTH-WP), assessing compliance with ICNIRP-2014 and EU Directive recommendations intended to prevent stimulation effects.

RESULTS

Peak values of |B| were greater than 2 T in nine of the 55 datasets. All the datasets at 1.5 T and 3 T were compliant with the limit for vertigo effects, whereas six datasets at 7 T turned out to be noncompliant. At 7 T, all 36 datasets were noncompliant for the SENS-WP index and 26 datasets even for the HLTH-WP one.

CONCLUSIONS

Results demonstrate that compliance with EU Directive limits for static fields does not guarantee compliance with ICNIRP-2014 reference levels and clearly show that movements in the static field could be the key component of the occupational exposure to EMF in MR facilities.

Evaluation of human exposure to complex waveform magnetic fields generated by arc-welding equipment according to European safety standards

In this paper, a procedure is described for the assessment of human exposure to magnetic fields with complex waveforms generated by arc-welding equipment. The work moves from the analysis of relevant guidelines and technical standards, underlining their strengths and their limits. Then, the procedure is described with particular attention to the techniques used to treat complex waveform fields. Finally, the procedure is applied to concrete cases encountered in the workplace. The discussion of the results highlights the critical points in the procedure, as well as those related to the evolution of the technical and exposure standards.

Quasi-Static Electromagnetic Dosimetry: From Basic Principles to Examples of Applications

An overview of quasi-static electromagnetic dosimetry is presented. After an introductive description of quantities and standards and a quick look at experimental and analytical approaches, attention is focused on numerical dosimetry. The process that leads to the calculation of results is analyzed in its basic steps, including the representation of the human body by means of a realistic voxel phantom. The most popular numerical methods are then described. An analysis of different methods in the same framework emphasizes common features and differences. This can help in choosing a more suitable method to solve a particular problem. An example of an application is finally reported.

Weighted-peak assessment of occupational exposure due to MRI gradient fields and movements in a nonhomogeneous static magnetic field

PURPOSE

A procedure for assessing occupational exposure due to magnetic resonance imaging (MRI) gradient magnetic fields and movement-induced effects in the static magnetic field is proposed and tested.

METHODS

The procedure was based on the application of the weighted-peak method in time domain. It was tested in two 1.5 T total-body and one 3 T head-only scanner MRI facilities in Rome (Italy). Exposure due to switched gradient fields was evaluated in locations inside the magnet room where operators usually stay during particular medical procedures (e.g., cardiac examinations of anesthetized patients); MRI sequences were selected to approach as far as possible a representative worst case exposure scenario. Movement-induced effects were evaluated considering the actual movements of volunteer operators during work activity, by measuring the perceived time-varying magnetic field by a head-worn probe. The analysis of results was based on ICNIRP 1998 and 2010 guidelines, following a weighted-peak approach and including an ad hoc extension to the latter ones, needed to verify compliance in the frequency range 0-1 Hz.

RESULTS

Exposures due to switched gradient fields in 1.5 T MRI scanners mostly resulted noncompliant with ICNIRP 1998 occupational reference levels, being, at the same time, always compliant with ICNIRP 2010 ones. Gradient field levels and ICNIRP indexes were significantly lower for the 3 T unit, due to its small dimensions, as that unit was a head-only scanner. Movement-induced effects resulted potentially noncompliant only in the case the operator moved the head inside the bore of a 1.5 T scanner.

CONCLUSIONS

The procedure had proven to be a sound approach to exposure assessment in MRI. Its testing allowed to draw some general considerations about exposures to gradient magnetic fields and movement-induced effects.

Exposure to electromagnetic fields from laptop use of "laptop" computers

Portable computers are often used at tight contact with the body and therefore are called "laptop." The authors measured electromagnetic fields (EMFs) laptop computers produce and estimated the induced currents in the body, to assess the safety of laptop computers. The authors evaluated 5 commonly used laptop of different brands. They measured EMF exposure produced and, using validated computerized models, the authors exploited the data of one of the laptop computers (LTCs) to estimate the magnetic flux exposure of the user and of the fetus in the womb, when the laptop is used at close contact with the woman's womb. In the LTCs analyzed, EMF values (range 1.8-6 μT) are within International Commission on Non-Ionizing Radiation (NIR) Protection (ICNIRP) guidelines, but are considerably higher than the values recommended by 2 recent guidelines for computer monitors magnetic field emissions, MPR II (Swedish Board for Technical Accreditation) and TCO (Swedish Confederation of Professional Employees), and those considered risky for tumor development. When close to the body, the laptop induces currents that are within 34.2% to 49.8% ICNIRP recommendations, but not negligible, to the adult's body and to the fetus (in pregnant women). On the contrary, the power supply induces strong intracorporal electric current densities in the fetus and in the adult subject, which are respectively 182-263% and 71-483% higher than ICNIRP 98 basic restriction recommended to prevent adverse health effects. Laptop is paradoxically an improper site for the use of a LTC, which consequently should be renamed to not induce customers towards an improper use.

Evaluation and characterization of fetal exposures to low frequency magnetic fields generated by laptop computers

Portable - or "laptop" - computers (LCs) are widely and increasingly used all over the world. Since LCs are often used in tight contact with the body even by pregnant women, fetal exposures to low frequency magnetic fields generated by these units can occur. LC emissions are usually characterized by complex waveforms and are often generated by the main AC power supply (when connected) and by the display power supply sub-system. In the present study, low frequency magnetic field emissions were measured for a set of five models of portable computers. For each of them, the magnetic flux density was characterized in terms not just of field amplitude, but also of the so called "weighted peak" (WP) index, introduced in the 2003 ICNIRP Statement on complex waveforms and confirmed in the 2010 ICNIRP Guidelines for low frequency fields. For the model of LC presenting the higher emission, a deeper analysis was also carried out, using numerical dosimetry techniques to calculate internal quantities (current density and in-situ electric field) with reference to a digital body model of a pregnant woman. Since internal quantities have complex waveforms too, the concept of WP index was extended to them, considering the ICNIRP basic restrictions defined in the 1998 Guidelines for the current density and in the 2010 Guidelines for the in-situ electric field. Induced quantities and WP indexes were computed using an appropriate original formulation of the well known Scalar Potential Finite Difference (SPFD) numerical method for electromagnetic dosimetry in quasi-static conditions.

A simplified procedure for dosimetric evaluations on ELF sources with complex waveforms

The endorsement of the 2004/40 European Directive has renewed the interest in numerical electromagnetic dosimetry. In this field, a need is clearly perceived for dosimetric approaches able to reduce costs and the time necessary for this type of evaluations. In the low and intermediate frequency ranges, EM dosimetry makes use of quasi-static techniques in the frequency domain, which become onerous when dealing with sources emitting multiple frequencies. A procedure is then proposed, able to greatly simplify the numerical process needed to perform a dosimetric calculation involving a complex waveform. The procedure is based on the use of an 'equivalent' field intensity at an arbitrarily chosen 'reference' frequency and allows executing a single-frequency dosimetric evaluation able to take into account, with some approximations, the complete spectral contents of the source signal.

Review of open problems in assessing compliance with 2004/40/EC directive exposure limit values for low-frequency current density by means of numerical techniques

The endorsement process of the 2004/40/EC Directive (still in progress) has led to a critical analysis of the ICNIRP Guidelines, on which the directive is based. In particular, some known problems affect the applicability of the numerical techniques needed for checking compliance with limits at low frequency. A review of these open problems is presented in the paper, highlighting how such problems deal more with pre-processing and post-processing steps than with the core numerical calculation of the current density.

Magnetic fields dispersed by high-voltage power lines: an advanced evaluation method based on 3-D models of electrical lines and the territory

An advanced numerical evaluation tool is proposed for calculating the magnetic flux density dispersed by high-voltage power lines. When compared to existing software packages based on the application of standardized methods, this tool turned out to be particularly suitable for making accurate evaluations on vast portions of the territory, especially when the contribution of numerous aerial and/or underground lines must be taken into account. The aspects of the tool of greatest interest are (1) the interaction with an electronic archive of power lines, from which all the information necessary for the calculation is obtained; (2) the use of three-dimensional models of both the power lines and the territory crossed by these; (3) the direct interfacing with electronic cartography; and finally (4) the use of a representation procedure for the results that is based on contour maps. The tool had proven to be very useful especially for Environmental Impact Assessment procedures relative to new power lines.