Can Electrocardiographic Criteria Predict Adverse Cardiac Events and Positive Cardiac Markers?

OBJECTIVES: To determine electrocardiogram (ECG) predictors of positive cardiac markers and short-term adverse cardiac events in an undifferentiated chest pain population presenting to emergency departments (EDs). The authors hypothesized that specific ECG findings, other than those previously identified in higher-risk populations, would be predictive of cardiac outcomes and positive cardiac markers. METHODS: This study used data from a prospectively collected, retrospectively analyzed Internet-based data registry of undifferentiated chest pain patients (i*trACS). Logistic regression modeling was performed to determine the ECG findings that were predictive of 1) positive cardiac markers and 2) short-term adverse cardiac events. RESULTS: ST-segment elevation (STE), ST-segment depression (STD), pathological Q-waves (PQW), and T-wave inversion were associated with increased odds of percutaneous coronary intervention or catheterization, myocardial infarction, or coronary artery bypass grafting. The odds of creatine kinase-MB (CK-MB) measuring positive were increased if STE, STD, or PQW were present [odds ratio (OR) 2.495, 2.582, and 1.295, respectively]. A right bundle branch block tended to decrease the odds of CK-MB measuring positive (OR 0.658). A similar pattern of results was observed for troponin I (OR 3.608 for STE, 3.72 for STD, 1.538 for PQW). Troponin T showed an increased odds of measuring positive if any of STE, STD, left bundle branch block, or T-wave inversion were evident (OR 2.313, 2.816, 1.80, and 1.449, respectively). CONCLUSIONS: Initial ECG criteria can be used to predict short-term cardiac outcomes and positive cardiac markers. These findings can be important aids in the risk-stratification and aggressive treatment regimens of chest pain patients presenting to EDs.     

Distance-adjusted motor threshold for transcranial magnetic stimulation.

OBJECTIVE: To examine the relationship between coil-cortex distance and effective cortical stimulation using transcranial magnetic stimulation (TMS) in the left and right motor cortex. We also compare the effect of coil-cortex distance using 50 and 70 mm figure-eight stimulating coils. METHODS: Coil-cortex distance was manipulated within each participant using 5 and 10 mm acrylic separators placed between the coil and scalp surface. The effect of cortical stimulation was indexed by resting motor threshold (MT). RESULTS: Increasing distance between the coil and underlying cortex was associated with a steep linear increase in MT. For each additional millimetre separating the stimulating coil from the scalp surface, an additional approximately 2.8% of absolute stimulator output (approximately 0.062 T) was required to reach MT. The gradient of the observed distance effect did not differ between hemispheres, and no differences were observed between the 50 and 70 mm TMS coils. CONCLUSIONS: Coil-cortex distance directly influences the magnitude of cortical stimulation in TMS. The relationship between TMS efficacy and coil-cortex distance is well characterised by a linear function, providing a simple and effective method for scaling stimulator output to a distance adjusted MT. SIGNIFICANCE: MT measured at the scalp-surface is dependent on the underlying scalp-cortex distance, and therefore does not provide an accurate index of cortical excitability. Distance-adjusted MT provides a more accurate index of cortical excitability, and improves the safety and efficacy of MT-calibrated TMS.     

A novel mutation in the last exon of ATRX in a patient with α-thalassemia myelodysplastic syndrome

Abstract:  We describe a patient with acquired alpha-thalassemia myelodysplastic syndrome (ATMDS). A previously healthy 66-year-old man presented with hemoglobin of 9.3 g/dL, mean corpuscular volume 59 fL, and a bone marrow aspirate with increased erythroid precursors and hypolobulated megakaryocytes. Hemoglobin H inclusions were seen in most red cells after 1% brilliant cresyl blue supravital stain of the peripheral blood. At the molecular level, we identified of a novel mutation in the most 3' exon of the ATRX gene ( C GA→ T GA substitution in codon 2407) resulting in a premature termination codon (p.R2407X). This case provides further evidence for a link between ATRX mutations and ATMDS, and suggests a possible role for the conserved Q-box element in ATRX function.     

The effect of light intensity on double bond conversion and flexural strength of a model, unfilled dental resin.

OBJECTIVE: Two visible light sources (tungsten-quartz-halogen and xenon-arc plasma) with vastly different intensities (200 and 1800 mW/cm(2)) but similar spectral outputs, were used to examine the effects of light intensity on conversion and flexural strength of a model dental resin formulation (75/25wt% bis-GMA/TEGDMA). METHODS: The exact same polymer samples were used to correlate double bond conversion (measured with near-IR spectroscopy) to flexural strength, both immediately after light exposure and after storage. RESULTS: In general, polymers which were irradiated with the high light intensity source exhibited greater double bond conversion. However, increasing the light intensity also increased the maximum temperature reached during polymerization. Therefore, the greater double bond conversion was caused by a combination of both photo and thermal effects. Regardless of the light intensity, a single linear relationship existed between conversion and final flexural strength (measured 4 days after cure) over the conversion range analyzed (50-80%). However, deviations from linearity were noted in several samples that were tested immediately after exposure. SIGNIFICANCE: These findings illustrate that light intensity does not affect the final flexural strength of a dental resin as long as the final conversions are similar.     

Intracranial Angioplasty and Stenting in the Awake Patient

BACKGROUND AND PURPOSE: Endovascular treatment for intracranial atherosclerosis is evolving, but complications remain an issue. Most interventions are performed under general anesthesia, preventing intraprocedural clinical evaluations. We describe our approach to intracranial angioplasty and stenting, using local rather than general anesthesia, and intraprocedural neurological assessment. METHODS: We prospectively collected procedural and outcome information on all patients undergoing intracranial angioplasty and stenting. Patients underwent interventions under local anesthesia with mild intravenous sedation or analgesia only if needed. Intraoperative neurological evaluations were performed, and symptomatology was used to guide the interventional technique. RESULTS: Forty-eight arteries in 40 patients with a mean age of 65.2 years were treated. Thirty-two anterior and 16 posterior circulation segments were treated. Technical success was achieved in 100% of patients with reduction of the mean pretreatment stenosis from 85 +/- 8.6% to 7 +/- 10.1%. Stents were deployed in 40 segments; five patients were treated with drug-eluting stents. The cobalt-chromium coronary stents were the easiest to deliver. Thirty-seven patients were treated under local anesthesia and, of those, 61.4% experienced intraprocedural symptoms that led to some alteration of the interventional technique. Headache was the most common symptom, and, when persistent, it heralded the occurrence of subarachnoid hemorrhage. There were seven total neurological complications, but only five (10.5%) led to permanent morbidity (4 strokes) or mortality (1 death). CONCLUSIONS: Intracranial angioplasty and stenting can be successfully performed using coronary techniques and equipment including drug-eluting stents. Local anesthesia permits neurological evaluations and often leads to the adjustment of the interventional technique, potentially making the procedure safer.     

EEG source imaging: correlating source locations and extents with electrocorticography and surgical resections in epilepsy patients.

SUMMARY: It is desirable to estimate epileptogenic zones with both location and extent information from noninvasive EEG. In the present study, the authors use a subspace source localization method (FINE), combined with a local thresholding technique, to achieve such tasks. The performance of this method was evaluated in interictal spikes from three pediatric patients with medically intractable partial epilepsy. The thresholded subspace correlation, which is obtained from FINE scanning, is a favorable marker, which implies the extents of current sources associated with epileptic activities. The findings were validated by comparing the results with invasive electrocorticographic (ECoG) recordings of interictal spike activity. The surgical resections in these three patients correlated well with the epileptogenic zones identified from both EEG sources and ECoG potential distributions. The value of the proposed noninvasive technique for estimating epileptiform activity was supported by satisfactory surgery outcomes.     

Comparison of morning versus afternoon cecal intubation rates

Background  

Many factors impacting cecal intubation rates have been examined in detail; however, little information exists regarding the effect of the timing of the procedure. We sought to examine any difference in cecal intubation rates between morning and afternoon colonoscopies and identify factors contributing to a discrepancy.     

Respiratory sinus arrhythmia during speech production.

The amplitude of the respiratory sinus arrhythmia (RSA) was investigated during a reading aloud task to determine whether alterations in respiratory control during speech production affect the amplitude of RSA. Changes in RSA amplitude associated with speech were evaluated by comparing RSA amplitudes during reading aloud with those obtained during rest breathing. A third condition, silent reading, was included to control for potentially confounding effects of cardiovascular responses to cognitive processes involved in the process of reading. Calibrated respiratory kinematics, electrocardiograms (ECGs), and speech audio signals were recorded from 18 adults (9 men, 9 women) during 5-min trials of each condition. The results indicated that the increases in respiratory duration, lung volume, and inspiratory velocity associated with reading aloud were accompanied by similar increases in the amplitude of RSA. This finding provides support for the premise that sensorimotor pathways mediating metabolic respiration are actively modulated during speech production.