Smith's Criteria Research Articles

LEFT BUNDLE BRANCH BLOCK AND ACUTE CORONARY SYNDROME: WHAT IS THE ROLE OF MODIFIED SGARBOSSA–SMITH CRITERIA AND THE WELLENS‘ PATTERN?

Abstract A 55–year–old man presented to the emergency room with intermittent chest pain that started the day before. His medical history included hypertension, and dyslipidemia. The initial electrocardiogram (ECG) showed sinus rhythm (75 bpm) with pre–existing left bundle branch block (LBBB), without modified Sgarbossa–Smith criteria, despite the hyperacute appearance of T waves in V2–V4 (Fig. 1). Additionally, there were alterations in ventricular repolarization in the lateral region, morphologically not fully justifiable by the mentioned conduction delay. Echocardiography revealed normal left and right ventricular systolic function and no valvular abnormalities. Laboratory tests showed a pathological release of myocardial necrosis enzymes, with a typical rise–and–fall curve (10 pg/mL, 100 pg/mL, 200 pg/mL; normal range: 1.7–34.2 pg/mL). Therefore, the patient was admitted to the intensive cardiac care unit (ICCU) with a working diagnosis of non–ST–segment elevation myocardial infarction (NSTEMI). There were no recurrent angina episodes or signs/symptoms of heart failure on physical examination. During hospitalization, ECG and echocardiography were repeated. The follow–up ECG (12 hours after admission) showed persistent LBBB with biphasic T waves in leads V2–V5 with slight negative deflection at the end. This T wave abnormality can be interpreted as Wellens’ ECG Type A (Fig. 3A). The echocardiogram remained unchanged. Consequently, the catheterization lab was activated for urgent coronary angiography. The examination revealed subocclusion of the mid–segment of the left anterior descending artery (LAD). A drug–eluting stent was deployed in the culprit lesion (Fig. 2), restoring coronary flow completely (TIMI Flow 3). The subsequent hospital stay proceeded without complications. The ECG performed before discharge showed a typical LBBB, with normalization of T waves in precordial leads (Fig 3B). The presented case is about ECGs containing a pre–existing LBBB pattern in a patient with chest pain. The modified Sgarbossa–Smith criteria were not met in either the first recorded ECG or the second, whereas Wellens’ signs were detectable. Wellens’ syndrome can be diagnosed in a case of LBBB and help detect a high–grade LAD stenosis even if modified Sgarbossa–Smith criteria are not met.

A RARE CASE OF DE NOVO ISCHEMIC LEFT BUNDLE BRANCH BLOCK RELATED TO A RIGHT CORONARY LESION

Introduction: ischemic left bundle branch block (LBBB) is left coronary occlusion. We report an atypical case of de novo ischemic LBBB in relation to a tight right coronary lesion. Material and methods: Mr H, 53 years old with no modifiable risk factors, consulted for a typical angina pain evolving since 4 hours. The per-critical ECG showed a complete de novo LBBB with criteria of acute coronary ischemia. Coronary angiography showed a tight lesion of the right coronary artery that was stented with a good evolution marked by the regression of symptoms and signs of LBBB ischemia. Discussion: Ischemic LBBB is a coronary emergency requiring urgent coronary reperfusion. The diagnosis is facilitated by the commonly used Sgarbossa and Smith criteria. An occlusion of the anterior interventricular artery is most often incriminated. There is no evidence of a relationship with a right coronary lesion. The literature is poor in the description of the culprit lesions in ischemic LBBB.

Refinement and derivation of statistical resolution limits for circular or rectilinear correlated sources in CES data models

This paper analyzes the deterministic (DCRB) and the stochastic (SCRB) Cramér-Rao bound on direction-of-arrival (DOA) estimation for two equi-powered correlated complex circular or rectilinear sources affected by complex circular white noise in different complex elliptically symmetric (CES) data models. Beginning by decomposing these CRBs, into factors depending on signal and noise parameters, and on geometric parameters of the array, some new interpretable closed-form expressions are derived in particular scenarios. These expressions provide useful insight into the behavior of these CRB’s dependence on the correlation factor. Approximate closed-form expressions of these CRBs for small DOA separation are also derived. These results lead to new formulas for statistical resolution limit (SRL) based on the Smith criterion at which an unbiased DOA estimation algorithm can resolve two closely-spaced circular or rectilinear sources. These SCRB-derived formulas are much less optimistic than those which have so far been deduced only from the DCRB under the assumption of known sources.

Malignant granular cell tumor of the arm – case report

Abstract Granular cell tumor (GCT) is a rare form of soft tissue cancer that is usually benign. Its malignant evolution is encountered in less than 2% of cases, having a more rapid and unfavorable evolution. Clinical presentation betraying malignant features could be increased tumor size, rapid growth, deep localization, and female gender. This paper presents the case of a 52-year-old patient with a hard, rapidly evolving tumor in the left arm. The diagnosis of granular cell tumor was made based on histopathological examination using the Fanburg and Smith criteria to differentiate the formation as malignant, but with certainty this was subsequently confirmed by the existence of a metastasis. Surgical excision was performed and the evolution was favorable. Evolution and treatment differ depending on the benign or malignant form, but surgical treatment with wide local excision is recommended. This may be followed by chemotherapy or radiotherapy, and follow-up of patients for the rest of their lives is mandatory.

Research on the Neal&Smith Criterion Application on Aircraft Flight Control System Handling Qualities Assessment

This paper utilized Neal&Smith criterion to quantify handling qualities of some aircraft augmented with Control and Stability Augmentation System (CSAS) over the flight envelop. Some aircraft mathematical model which augmented by longitudinal pitch Rate Command-Attitude Hold(RCAH) controller are employed. The aircraft handling qualities are described in terms of transfer functions of the pilot mathematical model, which includes a pilot’s neuromuscular delay, phase and gain compensation terms. If desirable closed loop dynamic performance can be obtained by the pilot mathematical model described by transfer function characteristics, then the satisfactory closed loop dynamic performance will also be achievable for the human pilot with decent workload. Consequently, the assessment results can be used to identify CSAS controller’s satisfactory effect domain, and furthermore, in aid of CSAS gain scheduling strategy design.

A systematic review of the association between a single strenuous event and the development of an inguinal hernia: A medicolegal grey area

Abstract Background Inguinal hernia is a common surgical presentation. Evidence for its causation regarding occupational and recreational physical exposures is limited. The aim of this study is to conduct a systematic review objectively evaluating the evidence for a causal link between a single strenuous event and the development of an inguinal hernia. Method A systematic review was carried out in accordance with PRISMA guidelines. PubMed, Ovid Embase, SCOPUS, and Cochrane Library were searched. In addition, the ISRCTN register, ClinicalTrials.gov, ICTR Platform, and EU Clinical Trials Register were searched. Identified publications were collated and both reviewers independently reviewed their contents. Findings 5508 records were identified, resulting in 5 studies being selected. These 5 studies were all case series. Of 957 patients identified, 1003 hernias were described, of which 983 were inguinal hernias which 255 (26%) were attributed by patients to a single strenuous event. Only two of these studies applied Smith's Criteria (causation of a hernia from a single strenuous event): officially reported, severe pain at the time of the event, no prior history of inguinal hernia, and the diagnosis was made by a doctor within 30 days (preferably 3 days). Only 2 of 54 patients (4%) met all four criteria and so could be considered as having an inguinal hernia relating to a single strenuous event. Conclusion Many patients associate hernias to a single episode, however upon application of more stringent criteria such as Smith's, a much smaller proportion are deemed to be actually attributable to a single strenuous event.

MIMO radar target localization and performance evaluation under SIRP clutter

Multiple-input multiple-output (MIMO) radar has become a thriving subject of research during the past decades. In the MIMO radar context, it is sometimes more accurate to model the radar clutter as a non-Gaussian process, more specifically, by using the spherically invariant random process (SIRP) model. In this paper, we focus on the estimation and performance analysis of the angular spacing between two targets for the MIMO radar under the SIRP clutter. First, we propose an iterative maximum likelihood as well as an iterative maximum a posteriori estimator, for the target's spacing parameter estimation in the SIRP clutter context. Then we derive and compare various Cramér–Rao-like bounds (CRLBs) for performance assessment. Finally, we address the problem of target resolvability by using the concept of angular resolution limit (ARL), and derive an analytical, closed-form expression of the ARL based on Smith's criterion, between two closely spaced targets in a MIMO radar context under SIRP clutter. For this aim we also obtain the non-matrix, closed-form expressions for each of the CRLBs. Finally, we provide numerical simulations to assess the performance of the proposed algorithms, the validity of the derived ARL expression, and to reveal the ARL's insightful properties.

Cramér–Rao bound and statistical resolution limit investigation for near-field source localization

In this paper, we investigate the performance analysis for near-field source localization in terms of the mean square error and resolvability. We first derive and analyze non-matrix, closed-form expressions of the deterministic Cramér–Rao bound for two closely spaced, time-varying near-field sources in the context of linear arrays. Numerical simulations confirm the validity of the obtained expressions. Using these expressions and based on Smith's criterion, we discuss the behavior of the statistical resolution limit with respect to some features of interest, namely, the correlation factor, the central frequency, the minimum resolution limit boundary and the array geometry. Finally, to avoid the complexity of the optimal geometry design procedure, we propose a fast, nearly optimal, array design scheme to enhance the capacity of resolvability under given constraints (e.g., number of sensors and array aperture).

On the Angular Resolution Limit for Array Processing in the Presence of Modeling Errors

In this correspondence, we study the impact of modeling errors on the angular resolution limit (ARL) for two closely spaced sources in the context of array processing. Particularly, we follow two methods based on the well-known Lee and Smith's criteria using the Cramer-Rao lower bound (CRB) to derive closed-form expressions of the ARL with respect to (w.r.t.) the error variance. We show that, as the signal-to-noise ratio increases, the ARL does not fall into zero (contrary to the classical case without modeling errors) and converge to a fixed limit depending on the method for which we give a closed-form expression. One can see that at high SNR, the ARL in the Lee and Smith sense are linear as a function of the error variance. We also investigate the influence of the array geometry on the ARL based on the Lee's and Smith's criteria.

Pilot modeling based on time-delay synthesis

A review of some human pilot models of the years 1970–1990 – the Kleinman–Baron–Levison optimal control model, the Davidson–Schmidt modified optimal control model, and the Hess optimal control model – has been presented from the perspective of a new model based on the optimal control synthesis of time-delay systems. In the first of the listed models, the ‘central nervous’ reaction of the pilot is naturally defined as a pure time delay in the measurement equation of the system. In the framework of the optimal control theory, the pilot’s behavior is modeled by linear quadratic regulator gain and Kalman–Bucy filter with a linear predictor. Starting from this optimal model of the 1970s, the other two models assumed the Padé approximation of the pure time delay, thus eliminating the linear predictor. In this article, the pure time delay of pilot reaction was reconsidered and divided, for convenience, into two equal parts: for the output measurement equation and for the input control. The pilot model problem has been first defined in the framework of rigorous time-delay synthesis and then solved by making reference to the control separation and duality principles. A closed-form expression of the solution is thereby obtained. The proposed model was then compared by numerical simulations with Kleinman and Hess consacrated models. The analysis of the results shows that this new pilot model is described by a simplified representation, instead denoting similar performance versus previous optimal models – which contains additional insertions as Kleinman–Baron predictor or Padé approximation, respectively. Finally, joint evaluation of the proposed model and Kleinman and Hess models with respect to the well-known Neal–Smith criterion confirms the consistency and viability of the employed strategy as a possible tool for pilot-induced oscillations phenomenon investigation.

Gut peptides in the control of food intake: 30 years of ideas

The demonstration of the ability of exogenous cholecystokinin (CCK) to inhibit food intake began a series of investigations into whether and how gut and brain peptides affected ingestive behavior. In that original demonstration, Gerry Smith and colleagues both established criteria for evaluating roles for gut peptides in food intake and shifted the focus of feeding controls to factors that contribute to limiting meal size. Although new gut peptides with novel mechanisms and durations of action have been identified in the past few years, Smith's criteria and his distinction between direct and indirect controls of meal size continue to provide a framework for understanding how such peptides may contribute to overall feeding control.

The range of congenital malformations associated with cleft lip and palate

The congenital malformations associated to cleft lip and cleft palate cover a wide range of pathologies with incidence and acuteness that vary according to the authors. In the 284 patients followed and/or referred to the Cleft Consultation of Dona Estefânia Hospital, 78 had associated malformations (27.5%). In three cases there was consanguinity in parents. A familial incidence of cleft and/or other congenital malformations was found in 13 and 10 patients respectively. Thirty patients had malformative syndromes. In the remaining 48, 127 associated congenital malformations (M.C.A.) were identified, in accordance with the Smith criteria, 81 major and 46 minor. The most frequent associated malformations are those of the face (25.9%) and of the cardiovascular system (16.5%). The multiple anomalies (of various systems) are the most frequent (47.9%), followed by the isolated anomaly (29.1%) and the multiple of one system (22.9%). In what concerns the association of syndromes with the type of cleft, primary, secondary or total palate, those of the secondary were the most frequent, particularly that of the Pierre Robin sequence (S.P.R.)--19 in 36 secondary cleft palate.

Development and validation of a clinical history form for the diagnosis of congestive heart failure.

Our aim was to develop and validate a new diagnostic tool for congestive heart failure (CHF) based only on clinical examination, medical history and current drug use. In the developmental phase, we enrolled 520 consecutive patients with heart disease of different etiology; the diagnosis of CHF was made by means of Smith's clinical and radiological criteria, and the Boston criteria, with a substantial interscale agreement (kappa = 0.89). The initial version of our Form included 37 items on clinical examination, medical history and drug use information. After an item reduction process, the final version of the Clinical History Form (CH Form) included 15 items, each with a score 1 to 4. The CH Form score showed a progressive, significant increase as NYHA Class increased. With a cut-off of 4 points, sensitivity was 88.6% and specificity 86.8% against Smith's criteria for diagnosis of CHF. Substantial interrater agreement was observed for all the 15 items (kappa > 0.6) on a subsample of 250 patients. In the validation phase, we studied an independent sample of 72 patients with heart disease. The CH Form was significantly correlated with left ventricular ejection fraction (r = 0.42; p < 0.0005) and peak oxygen consumption (r = 0.69; p < 0.0001). In the 64 (89%) patients who underwent non-emergent right-heart catheterization, the CH Form score was significantly correlated with pulmonary capillary wedge pressure (r = 0.84; p < 0.0001). The CH Form may represent a useful instrument for the diagnosis of CHF.

Flight controller design for uncertain and nonlinear plants with pilot compensation

Nonlinear quantitative feedback theory (QFT) is used to design a flight control system for the nonlinear model of the YF-16 aircraft (A/C) with C* as the controlled output. The resulting closed loop stability augmentation system (SAS), Pe(S), becomes part of the outer loop containing the pilot. The Neal-Smith pilot model for a compensatory tracking task is used to develop a technique which allows the designer to synthesize compensation in the outer loop, which includes a free compensator Fp(S). The latter is chosen to minimize pilot workload, increase system bandwidth, and improve handling qualities ratings as per the Neal–Smith criteria, for the tracking task. The available pilot compensation abilities are then available for further increasing of system bandwidth to improve overall capabilities. This approach can be used at the early stages of flight control design, thus saving time and money over the current practice. Simulations in the time and frequency domains demonstrate that the desired performance is attained.

Prediction and occurrence of pilot-induced oscillations in a flight test aircraft

Flight testing of a high-performance aircraft was conducted several years ago and again during the past two years. During the first flight tests, a pilot-induced oscillation was experienced in the pitch axis during the time between the landing flare and touchdown. During the more recent flight tests two pilot-induced oscillations were experienced in the pitch axis during up-and-away flight. One of these occurred while the pilot attempted to track a cockpit display. Math models of the aircraft were used with three handling qualities criteria to determine the predicted handling qualities of the aircraft. These predictions were compared with flight test results. The handling qualities criteria used were the equivalent systems, bandwidth, and R. Smith criteria. The handling qualities predicted by each of these criteria agreed well with flight test results. The R. Smith criteria were especially interesting because they predicted the likelihood of pilot-induced oscillation explicitly and correctly and also predicted the frequency of each pilot-induced oscillation correctly. The predictions and flight test results also highlighted the impact that pilot displays can have on handling qualities. g n/a.

On necessary and sufficient conditions for group selection efficacy

The statement “group selection predominates over individual selection” is formulated within a class of patch-structured models. Conditions involving both “selfish” and “altruistic” predator characteristics are then shown to be necessary and sufficient for group selection predominance in this class of models. Maynard Smith's criterion M < 1 (Group selection, Quart. Rev. Biol., June 1976, pp. 277–283) is shown to be sufficient but not necessary for group selection predominance.

Evaluation of a String Test in Nonbleeding Individuals

Using the commercially available gastrointestinal string, type 2, we evaluated the string test without fluorescein in 15 volunteers who had no evidence of gastrointestinal tract disease or bleeding. Six subjects (40 %) had significant blood stains on the string using Smith's criteria. Such a large proportion of false positive results emphasizes the limited diagnostic usefulness of this variation of the string test.