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Objectives: Microcirculatory alterations are associated with adverse outcome in subsets of critically ill patients. The prevalence and significance of microcirculatory alterations in the general ICU population are unknown. We studied the prevalence of microcirculatory alterations in a heterogeneous ICU population and its predictive value in an integrative model of macro- and microcirculatory variables., Design: Multicenter observational point prevalence study., Setting: The Microcirculatory Shock Occurrence in Acutely ill Patients study was conducted in 36 ICUs worldwide., Patients: A heterogeneous ICU population consisting of 501 patients., Interventions: None., Measurements and Main Results: Demographic, hemodynamic, and laboratory data were collected in all ICU patients who were 18 years old or older. Sublingual Sidestream Dark Field imaging was performed to determine the prevalence of an abnormal capillary microvascular flow index (< 2.6) and its additional value in predicting hospital mortality. In 501 patients with a median Acute Physiology and Chronic Health Evaluation II score of 15 (10-21), a Sequential Organ Failure Assessment score of 5 (2-8), and a hospital mortality of 28.4%, 17% exhibited an abnormal capillary microvascular flow index. Tachycardia (heart rate > 90 beats/min) (odds ratio, 2.71; 95% CI, 1.67-4.39; p < 0.001), mean arterial pressure (odds ratio, 0.979; 95% CI, 0.963-0.996; p = 0.013), vasopressor use (odds ratio, 1.84; 95% CI, 1.11-3.07; p = 0.019), and lactate level more than 1.5 mEq/L (odds ratio, 2.15; 95% CI, 1.28-3.62; p = 0.004) were independent risk factors for hospital mortality, but not abnormal microvascular flow index. In reference to microvascular flow index, a significant interaction was observed with tachycardia. In patients with tachycardia, the presence of an abnormal microvascular flow index was an independent, additive predictor for in-hospital mortality (odds ratio, 3.24; 95% CI, 1.30-8.06; p = 0.011). This was not true for nontachycardic patients nor for the total group of patients., Conclusions: In a heterogeneous ICU population, an abnormal microvascular flow index was present in 17% of patients. This was not associated with mortality. However, in patients with tachycardia, an abnormal microvascular flow index was independently associated with an increased risk of hospital death.

Gait abnormalities can be studied by means of instrumented gait analysis. Foot-switches are useful to study the foot-floor contact and for timing the gait phases in many gait disorders, provided that a reliable foot-switch signal may be collected. Considering long walks allows reducing the intra-subject variability, but requires automatic and user-independent methods to analyze a large number of gait cycles. The aim of this work is to describe and validate an algorithm for the segmentation of the foot-switch signal and the classification of the gait cycles. The performance of the algorithm was assessed comparing its results against the manual segmentation and classification performed by a gait analysis expert on the same signal. The performance was found to be equal to 100% for healthy subjects and over 98% for pathological subjects. The algorithm allows determining the atypical cycles (cycles that do not match the standard sequence of gait phases) for many different kinds of pathological gait, since it is not based on pathology-specific templates.

Patient flow within a healthcare facility may follow different and, sometimes, complicated paths. Each path phase is associated with the documentation of the activities carried out during it and may require the consultation of clinical guidelines, medical literature and the use of specific software and decision aid systems. In this study we present the design of a Patient Flow Management System (PFMS) based on Multi Agent Systems (MAS) methodology. System requirements were identified by means of process modeling tools and a MAS consisting of six agents was designed and is under construction. Its main goal is to support both the medical staff during the health care process and the hospital managers in assuring that all the required documentation is completed and available. Moreover, such a tool can be used for the assessment and comparison of different clinical pathways, in order to identify possible improvementsand the optimum patient flow.

The optimization of the clinical staff resources is a very complicated task that can be supported by a set of tools called Patient Classification Systems (PCS). These methods allow the evaluation of the correct number of nurses and healthcare workers needed in order to guarantee an appropriate care level.

Time-frequency plots are widely applied to the non-stationary analysis of signals. These plots may be difficult to interpret, particularly when large data sets have to be considered. The aim of this work is to propose an automatic procedure of feature selection and clustering to be applied to time-frequency plots. We focus on the application of this procedure to plots obtained from a non-stationary analysis of the center-of-pressure signals acquired in upright bipedal stance. From a data set of 168 time-frequency plots we obtained 5 different clusters, each characterized by a few distinctive features. We were able to interpret the results of the clustering relating them to the physiological mechanisms underlying postural sway.

The pathophysiology of sepsis-induced acute kidney injury remains poorly understood. As changes in renal perfusion and oxygenation have been shown, we aimed to study the short-term effects of endotoxemia on microvascular and interstitial oxygenation in the cortex and medulla, in conjunction with global and renal hemodynamics. In a 4-h rat model of endotoxemia, we simultaneously assessed renal artery blood flow and microvascular and interstitial oxygen tensions in the renal cortex and medulla using ultrasonic flowmetry, dual wavelength phosphorimetry, and tissue oxygen tension monitoring, respectively. Whereas medullary microvascular and interstitial oxygen tensions decreased promptly in line with macrovascular blood flow, changes in cortical oxygenation were only seen later on. During the entire experimental protocol, the gradient between microvascular PO₂ and tissue oxygen tension remained unchanged in both cortex and outer medulla. At study end, urine output was significantly decreased despite a maintained oxygen consumption rate. In this 4-h rat model of endotoxemia, total renal oxygen consumption and the gradient between microvascular PO₂ and tissue oxygen tension remained unaltered, despite falls in renal perfusion and oxygen delivery and urine output. Taken in conjunction with the decrease in urine output, our results could represent either a functional renal impairment or an adaptive response.

The automated tracing of the carotid layers on ultrasound images is complicated by noise, different morphology and pathology of the carotid artery. In this study we benchmarked four methods for feature selection on a set of variables extracted from ultrasound carotid images. The main goal was to select those parameters containing the highest amount of information useful to classify the pixels in the carotid regions they belong to. Six different classes of pixels were identified: lumen, lumen-intima interface, intima-media complex, media-adventitia interface, adventitia and adventitia far boundary. The performances of QuickReduct Algorithm (QRA), Entropy-Based Algorithm (EBR), Improved QuickReduct Algorithm (IQRA) and Genetic Algorithm (GA) were compared using Artificial Neural Networks (ANNs). All methods returned subsets with a high dependency degree, even if the average classification accuracy was about 50%. Among all classes, the best results were obtained for the lumen. Overall, the four methods for feature selection assessed in this study return comparable results. Despite the need for accuracy improvement, this study could be useful to build a pre-classifier stage for the optimization of segmentation performance in ultrasound automated carotid segmentation.

Biomedical technology is strategically important to the operational effectiveness of healthcare facilities. As a consequence, clinical engineers have become an essential figure in hospital environment: their role in maintenance, support, evaluation, integration, assessment of new, advanced and complex technologies in point of view of patient safety and cost reduction is become inalienable. For this reason, nations have begun to establish Clinical Engineering Department, but, unfortunately, in a very diversified and fragmented way. So, a tool able to evaluate and improve the quality of current services is needed. Hence, this work builds a model that acts as a reference tool in order to assess the quality of an existing Clinical Engineering Department, underlining its defaulting aspects and suggesting improvements.

Chagas disease is a parasitic illness endemic in 21 countries of Central and South America, affecting over 10 million people. Due to the increase of migration flows to Europe, Chagas disease is an emerging public health issue in non endemic countries. In Italy, where no specific policy has yet been developed, the Centre for International Health of the University of Bologna is carrying out the project "Chagas disease in a non endemic country: a study in the district of Bologna". A multidisciplinary and multi-method approach was adopted to estimate the problem and its impact in our territory. A retrospective analysis was performed searching several databases in order to collect information concerning the demographic and epidemiological profile of Latin American migrants coming from endemic countries. At the same time, a preliminary ethnographic research was conducted to start unveiling the main socio-anthropological characteristics of this population, thanks to the involvement of key informants and community associations. According to preliminary findings, Chagas disease is a present and possibly increasing reality in our territory. Due to the particular features of the affected population, socio-cultural variables have to be considered for their impact on the visibility of the condition and on health seeking behaviors.

Objective: The influence of teaching leadership on the performance of rescuers remains unknown. The aim of this study was to compare leadership instruction with a general technical instruction in a high-fidelity simulated cardiopulmonary resuscitation scenario., Design: Prospective, randomized, controlled superiority trial., Setting: Simulator Center of the University Hospital Basel in Switzerland., Subjects: Two-hundred thirty-seven volunteer medical students in teams of three., Intervention: During a baseline visit, the medical students participated in a video-taped simulated witnessed cardiac arrest. Participants were thereafter randomized to receive instructions focusing either on correct positions of arms and shoulders (technical instruction group) or on leadership and communication to enhance team coordination (leadership instruction group). A follow-up simulation was conducted after 4 mos., Measurements and Main Results: The primary outcome was the amount of hands-on time, defined as duration of uninterrupted cardiopulmonary resuscitation in the first 180 secs after the onset of the cardiac arrest (hands-on time) [corrected]. Secondary outcomes were time to start cardiopulmonary resuscitation, total leadership utterances, and technical skills. Outcomes were compared based on videotapes coded by two independent researchers. After a balanced performance at baseline, the leadership instruction group demonstrated a longer hands-on time (120 secs; interquartile range, 98-135 vs. 87 secs; interquartile range, 61-108; p < .001), a shorter median time to start cardiopulmonary resuscitation (44 secs; interquartile range, 32-62; vs. 67 secs; interquartile range, 43-79; p = .018), and had more leadership utterances (7; interquartile range, 4-10; vs. 5; interquartile range, 2-8; p = .02) in the follow-up visit. The rate of correct arm and shoulder positions was higher in teams with technical instruction (59%; 19 out of 32; vs. 23%; 7 out of 31; p = .003)., Conclusions: Video-assisted leadership and technical instructions after a simulated cardiopulmonary resuscitation scenario showed sustained efficacy after a 4-mo duration. Leadership instructions were superior to technical instructions, with more leadership utterances and better overall cardiopulmonary resuscitation performance.

The automated segmentation of the carotid artery wall from ultrasound images is required for an accurate measurement of the artery intima-media thickness. Segmentation accuracy of automated techniques is usually limited by noise and artifacts. In 2005, the authors developed a methodology called CULEX whose performance was noise sensitive. The final stage of CULEX segmentation was fuzzy clustering of the pixels, to detect the lumen-intima (LI) and media-adventitia (MA) carotid wall interfaces. In this paper, we show the effect of a fuzzy Mamdani-type pre-classifier used to improve the segmentation performance. Thanks to the Mamdami fuzzy pre-classifier, we optimized the de-fuzzyfication threshold, increasing the LI and MA performance by 62% and 3.5%, respectively. The obtained segmentation errors (55.6 ± 69.4 microm for LI and 34.4 ± 24.4 microm for MA), validated against human tracings and on a 200-images dataset containing a mixture of healthy and plaque vessels.

Clinical Engineering (CE) Departments are in charge of healthcare technology management in healthcare facilities. The workload is proportional to the number of activities, the number and complexity of biomedical instrumentation, and the technology intensity of the facility. Clinical engineers and Biomedical equipment technicians work together in order to perform the different activities and to obtain customer satisfaction. This paper describes a model that can be used to estimate the number of engineers and technicians required to start a new CE Department. The estimation is obtained by means of simulation. Starting by several inputs that describe the facility and the quantity and characteristics of the instruments the model is able to provide the number of Clinical engineers and Biomedical equipment technicians.

Health technology management consists of several decision processes including the acquisition of new technology. The purchasing of a new device requires the selection of one among several products taking into account different criteria. When the technology is characterized by large amount of parameters the choice becomes problematical and a support tool is needed. In 2003 Sloane et al. published a study in which they demonstrated the potentialities of the Analytic Hierarchy Process (AHP) to support the selection of a biomedical instrumentation. The work presented here describes the application of AHP to support the quality assessment for the selection of pacemakers and implantable defibrillators and shows that the method is indeed very appropriate for that task.

Aims: To evaluate the feasibility of lesion related treatment strategies in patients treated for severe carotid artery disease with angioplasty and stenting (CAS) under embolic protection devices (EPD)., Methods and Results: From December 2001 to August 2004 a total of 377 consecutive patients were enrolled to undergo CAS. The procedure was conducted by using several types of stents (cobalt-alloy frame, nitinol frame) and of EPD (filter-wires, proximal endovascular clamping devices) applied to specific lesions and/or anatomies.Primary endpoint was to assess the death and stroke rate at discharge.Secondary endpoints were to test the feasibility and safety of tailored CAS (angiographic success, any -complication between discharge and 30 days, death of any cause at 30 days).The procedural success was achieved in 377/377 patients (100%).Adverse events included:1. during procedure: 2 TIAs (0.53%)2. at discharge: 1 death procedure related (0.27%), 1 major stroke (0.27%), 2 minor strokes (0.53%), 4 TIAs (1.06%), 1 intracranial hemorrhage (0.27%); all adverse event rate at discharge 2.92%; all strokes and death rate at discharge 1.06%;3. at 30 day f.u.: one death not procedure related (0.27%), 1 minor stroke (0.27%);4. overall procedure related stroke and death rate: 1.33%., Conclusions: Our data suggest that using new materials/devices matched to specific lesions or anatomies is safe and effective.

This paper considers the data and information needs for a broad range of environments, focusing on information-poor environments that may be well resourced in other respects. A generic framework for the establishment of a comprehensive healthcare technology management information system (HTMIS) is suggested.

This paper presents the development of a decision aid tool based on a fuzzy classifier. The goal was to obtain a system that could support a physician who have to make decisions about how to deal with the progression of the disease of a child affected by Duchenne Muscular Dystrophy. First, we used an outranking multicriteria method to select among the possible parameters of muscle fatigue evaluation the subset that provide more reliable information, than we used the selected parameters as membership functions for the fuzzy classifier. The output of the fuzzy classifier consisted of three classes: 1-"close to normal results", 2-"results compatible with moderate pathological conditions", and 3-"results congruent with severe pathological conditions". A first test of the classifier was performed using the data of the twenty examinations of six children and it provided good results. We believe that these results are relevant to the clinical applications and they can be easily extended to different pathologies.

Purpose: To evaluate the impact of cerebral protection devices on the procedural safety and outcome of carotid stent procedures., Methods: From June 1997 to July 2001, 275 consecutive patients (208 men; mean age 71 +/- 7.4 years) underwent percutaneous angioplasty and/or stenting of the extracranial carotid artery. In the first 125 (45.4%) patients, the procedures were performed without cerebral protection. After January 2000, protection devices were routinely used (150 [54.6%] patients), including the Angioguard filter, GuardWire occlusion system, TRAP Vascular Filtration System, EPI Filter Wire, NeuroShield, Parodi Anti-Embolism System, and Medicorp occlusive balloon., Results: The percutaneous procedures were effective in 273 (99.3%) patients. No death or major stroke occurred in either group. In the unprotected group, 5 (4.0%) complications occurred: 3 (2.4%) minor strokes, 1 (0.8%) transient ischemic attack (TIA), and 1 (0.8%) subarachnoid hemorrhage. In the patients treated under cerebral protection, there were 2 (1.3%) complications: 1 (0.7%) minor stroke and 1 (0.7%) subarachnoid hemorrhage. There were 4 (3.2%) periprocedural embolic complications in the unprotected group versus 1 (0.7%) in the protected patients., Conclusions: Our data suggest that percutaneous dilation and stenting of the carotid arteries protected by cerebral protection devices is feasible and effective. In a consecutive series, the use of the cerebral protection systems reduced the acute neurological event rate related to embolic complications by 79%.

Background: Treatment of HIV-1-infected individuals with antiretrovirals can result in sustained suppression of plasma viral RNA at concentrations below the detection limit of available assays. However, continuing virus replication has been detected in patients with viral RNA in plasma suppressed for months to years, and many cell types are known to act as reservoirs or carriers for the virus. In vitro, erythrocytes bind HIV-1 immune complexes, so we tested for a circulating pool of HIV-1 associated with erythrocytes in people with HIV-1 infection., Methods: We investigated 82 chronically HIV-1-infected individuals. Plasma, white cells, and erythrocytes were tested for HIV-1 RNA by RT-PCR., Findings: Erythrocyte-associated HIV-1 RNA was detected in 80 of 82 individuals. In 23, plasma HIV-1 RNA had been undetectable (<20 copies/mL) for up to 32 months; in corresponding erythrocyte samples, there were up to 82878 HIV-1 RNA copies per mL whole blood. HIV-1 associated with erythrocytes in vivo was shown to be infectious. Within the subgroup of patients with undetectable plasma viral load, higher numbers of HIV-1 associated with erythrocytes were correlated with a history of advanced clinical stages of HIV-1 infection (p=0.014)., Interpretation: A pool of HIV-1 is associated with erythrocytes even after long-term suppression of viral RNA in plasma. This finding is direct evidence for continuing virus replication or release in these individuals. Quantification of this viral pool may help to judge suppression of HIV-1 replication in individuals with undetectable plasma HIV-1 RNA.

Background: Carotid angioplasty and stenting are still not widely accepted treatments for carotid stenosis. This registry was aimed at investigating the efficacy of endovascular therapy of the extracranial carotid arteries in a non-selected population., Methods: One hundred nineteen consecutive patients (93 males and 26 females, mean age 70.4 +/- 7.2 years) were enrolled to undergo percutaneous angioplasty and/or stenting of the extracranial carotid artery. The primary endpoint of this study was to evaluate the feasibility, safety and efficacy of carotid elective angioplasty and stenting in a "real life group" of patients (> 50 years, without strict target vessel selection or inclusion criteria) with carotid occlusive disease. During a 6-12 month follow-up period late major adverse events were evaluated, either related to the endovascular treatment or due to other pathological conditions., Results: Percutaneous procedure was effective in 118/119 patients (99.16%). Procedural success rate was 99.16%, in-hospital major neurological symptomatic complications 0%, in-hospital minor neurological symptomatic complications 3.36% (two minor strokes, one transient ischemic attack and one subarachnoid hemorrhage). The follow-up observation time ranged from 6 to 36 months following the percutaneous procedure. Overall follow-up data showed absence of late major adverse events related to carotid disease (stroke, permanent neurological damage, death), in-stent restenosis 5.04%, balloon expandable stent crush 0.84%, stent migration 0.84%., Conclusions: Our data confirm that percutaneous dilation and stenting of the carotid artery represent an effective method which, during the periprocedural phase and the follow-up, does not expose the patient to any greater risk of complications than traditional surgery.

Severe atherosclerotic lesion of carotid artery is the main cause of stroke and transient ischemic attack (TIA). Its incidence may reach 5-7% per annum in patients with carotid artery stenosis higher than 70% with or without symptoms. While time-honored carotid endarterectomy is still regarded as the "gold standard" therapy for most of the patients, carotid angioplasty with stent may be the only alternative to this treatment when endarterectomy is too risky or impossible. Although percutaneous angioplasty has been fully acknowledged as far as coronary or peripheral artery disease is concerned, the issue is still controversial in the endovascular treatment of carotid artery disease with regard to its indications, devices to be used and long-term results. Assessment of risk relating to carotid angioplasty with stent in comparison to carotid endarterectomy continues to be difficult, since materials and methods for this approach have not been standardized yet. Our initial experience in carotid angioplasty with stent performed in 21 consecutive patients by using devices for coronary angioplasty is extremely encouraging.

The occurrence of legionnaires' disease has been described previously in passengers of cruise ships, but determination of the source has been rare. A 67-year-old, male cigarette smoker with heart disease contracted legionnaires' disease during a cruise in September 1995 and died 9 days after disembarking. Legionella pneumophila serogroup 1 was isolated from the patient's sputum and the ship's water supply. Samples from the air-conditioning system were negative. L. pneumophila serogroup 1 isolates from the water supply matched the patient's isolate, by both monoclonal antibody subtyping and genomic fingerprinting. None of 116 crew members had significant antibody titers to L. pneumophila serogroup 1. One clinically suspected case of legionnaires' disease and one confirmed case were subsequently diagnosed among passengers cruising on the same ship in November 1995 and October 1996, respectively. This is the first documented evidence of the involvement of a water supply system in the transmission of legionella infection on ships. These cases were identified because of the presence of a unique international system of surveillance and collaboration between public health authorities.

Purpose: This study quantified the bacterial load and protein deposits on 1- and 15-day disposable contact lenses after use in normal wearers., Methods: Sixteen patients were randomly assigned to a 1-day contact lens (1-Day Acuvue) in one eye and to a 15-day contact lens (Acuvue) in the contralateral eye. Only one specified solution was allowed for the care of 15-day lenses. All patients were evaluated every month for 6 months (at times T1, T2, T3, T4, T5, T6). At times T1, T3, and T5, the lenses were removed in a sterile fashion and sent for laboratory quantification of Staphylococcus aureus and Pseudomonas aeruginosa. At T2, T4, and T6, quantification of protein deposits was determined, and at T0 and T6, impression cytology of the conjunctiva was performed., Results: P. aeruginosa was not identified on any lens. At T1, T3, and T5, S. aureus was significantly greater on the 1-day versus 15-day lenses (p < 0.001). In contrast, protein deposits were significantly greater on the 15-day lenses at all time points (T2, T6: p < 0.01; T4: p < 0.05). Impression cytology of the 15-day lens eyes revealed a worsening trend compared to the 1-day lens; however, no statistically significant differences were found between the two groups (p = 0.29)., Conclusion: Results of this study suggest that the use of cleaning and preservative solutions can alter the ocular surface bacterial environment of the contact lens wearer and that these changes are not a direct consequence of contact lens wear. The bactericidal activity of these solutions could, with time, also affect ocular surface cells, leading to contact lens intolerance and ocular surface disease.

Renal artery stenosis is the most common surgically or interventionally curable cause of hypertension. Screening and diagnostic tests are still needed to establish the presence of renal artery stenosis. The aim of our study was to evaluate sensitivity, specificity and diagnostical accuracy of renal artery duplex scanning for diagnosis of renal artery stenosis in hypertensive patients. Between January 2, 1988 and December 31, 1989 we performed renal artery duplex scanning in 128 hypertensive patients in whom were present clinical data suggestive of renal artery stenosis. Angiographic evaluation was performed within 3 months in 23 patients with a positive duplex, and in 15 patients with a negative duplex but highly suggestive for renal artery stenosis clinical data. Studies were performed with an Ultramark 8 duplex scanner (ATL). Data of this report are relative to the analyses performed of 76 renal arteries. Duplex scanning had a sensitivity of 90% and specificity of 96% to detect renal artery stenosis. Diagnostic accuracy was 93% for 50% to 60% stenosis and 100% for occlusion or 60% to 99% renal artery stenosis. Duplex scanning for diagnosis of renal artery stenosis shows agreement with angiography. Duplex scanning, which can distinguish high grade stenosis from occlusion, is able to select patients for possible percutaneous transluminal angioplasty before angiography, and we consider duplex scanning a valid, noninvasive screening or diagnostic test for renovascular hypertension.

We are proposing a personal computer local network system for collecting data and managing of both cardiovascular in- and outpatients. The six PCs used as work stations are located in the following areas: reception desk, ergometry, holter, echocardiography, secretarial and coronary care unit and cardiology department. Starting from a commercially available DBMS program, an "Iceberg" applied program was first made in a single personal computer and then transferred to a local network. The tree-structured data base includes the cardiopathies list, the vasculopathies list, some cardiovascular clinical data and all information regarding cardiological instrumental tests. The data are descriptive, numeric, date, text and comment. The operative program allows us to change the data base without the help of the software house staff, so the system is adaptable to cardiological departments with different instrumental equipment and sections. The report of instrumental tests and the issuing of the discharge letter are made with the local work station, with simultaneous compiling, storing and printing. It is then possible, using any work station, to restore and print quickly a summary of all data concerning each patient. This summary permits us, in nearly all cases, to identify the patient's history and present condition, as well as the diagnostical steps taken.

10 patients with documented ischaemic heart disease were undergone to atrial pacing (AP) before and after administration of nifedipine. The lactate utilization (%L), ischaemic ST, angor were tested in the same conditions before and after the drug. Six patients presented negative lactate utilization (-%L) during AP before the drug and four had decreased %L during recovery. -%L was removed by the drug, in those without -%L nifedipine is able to provocate the same paradoxically. Nevertheless angor disappears n all cases while the ischaemic ST is irregulary eliminated. Paradoxical -%L after nifedipine was not assumed as result of damage of the coronary flow, as ischaemic ST and angor disappear. Probably this is the sign of byochemical block of piruvate-deydrogenasy due to the Ca++ antagonist action of nifedipine. Nifedipine favorable action was explained by the increased %L in patients with low %L during recovery time, that is expression of a increased aerobic metabolism.

On the basis of the personal experience of 36 patients with sick sinus syndrome, the role of length, seat, frequency of atrial stimulation (AS) on the duration of correct sinus node recovery time (CSNRT) were examined. The length of AS has little importance for values over 2 minutes. In 2 cases the CSNRT were pathological only if the position had been changed from the lateral wall of the right atrium to the middle right atrium. The frequency of AS is very important for the duration of pathological and maximal CSNRT. Therefore it is better to give every patient the major range of frequencies of AS as for a correct quantitative determination of sinus dysfunction so as not to lose some falsely negative results.

Personal experience in 12 cases of atrial flutter treated with various types of atrial electrostimulation is reported. In 6 cases the sinusal rhythm was obtained immediately. In the remaining cases sinusal rhythm was also obtained with atrial fibrillation from a minimum of 2 minutes to a maximum of 48 hours.

A new technique for recording His bundle and right branch potential through the veins of the arm instead of by the femoral route is described. Recordings were carried out in 70 patients. In 10, His potential was recorded simultaneously by the femoral and brachial routes. Potentials proved to be similar as regards morphology and duration; A-V conduction time proved identical while there were slight variations in His node conduction time since the atriogram revealed varying intrinsic deflexions. It is thus possible to confirm that the recording of His potential by the brachial route offers various advantages: 1) it takes less time than the femoral route; 2) it is an excellent alternative if, for various reasons, the patient cannot be examined by the femoral route; 3) His potential can be monitored more easily because of the greater stability of the catheter and the provisional electrosimulation using the same catheter when necessary; 4) contemporaneous recording of right branch and His bundle potential is possible in association with the femoral technique with better results than those obtained using multipolar catheters; 5) it is without complications: i.e. the phlebitis, phlebothrombosis, a-v fistula, and pulmonary emboly which, however rarely, may occur when using the femoral route.

78 patients who underwent disc prostheses replacement, 36 in mitral area, 58 in aortic area were studied by echocardiography. The Authors found 5 cases of malfunction, 3 in mitral area and 2 in aortic area. Regarding mitral malfunctions in 1 case a valve thrombosis was found; in 2 cases there was a partial leak. Regarding aortic malfunctions there was paravalvular leak. In mitral area malfunctions the Authors found alterations of the disc morphology during diastolic opening time associated with alteration of opening time. An increased diastolic closure velocity in 2 cases of paraprosthetic leak was found. A diagnostic element in the case with thrombosis was variability of maximal disc escursion during the same recording, because opening time variability never got over 10 m. seconds. In aortic area malfunctions the Authors found a constant fluttering of anterior mitral leaflet, a sinergic septal motion with the posterior wall and in 1 case the presence of disc opening before the first component of the first sound. The Authors underline the importance of simultaneous eco-phonocardiographic examination and the check-ups for the time to be.

10 patients with documented heart disease were undergone to atrial pacing (AP) combined to metabolic study. A negative lactate utilization (-%L) noticed in SC (coronary synus) represents a sure proof of a subordinate pacing ischaemia. As the negative lactate utilization is absent a significative reduction of %L during AP or its persistence in recovery and a rise of L/P are further parameters of a subordinate pacing ischaemia. The Authors consider the usefulness of combining a metabolic study to AP in assessing the RC (coronary reserve).

12 patients with normal QRS either in basal condition or during atrial pacing, undergone on single premature atrial stimulation, showed several types of intraventricular aberrancies. These have been revalued with atrial premature stimulation introduced over a progressively increasing frequency of fixed atrial stimulation (extrastimulus method), sometimes after atropine. In 9 cases it was possible to eliminate completely the above mentioned aberrancies, having thus a clear reduction of the refractory periods regarding their responsible structures. In 3 cases this was not possible, owing to a less significant reduction of the refractory periods. Such fenomenon is considered as the only parameter able to identify probable initial organic facts of the His-Purkinje system.