Automatic wide complex tachycardia differentiation using mathematically synthesized vectorcardiogram signals

BackgroundAutomated wide complex tachycardia (WCT) differentiation into ventricular tachycardia (VT) and supraventricular wide complex tachycardia (SWCT) may be accomplished using novel calculations that quantify the extent of mean electrical vector changes between the WCT and baseline electrocardiogram (ECG). At present, it is unknown whether quantifying mean electrical vector changes within three orthogonal vectorcardiogram (VCG) leads (X, Y, and Z leads) can improve automated VT and SWCT classification.MethodsA derivation cohort of paired WCT and baseline ECGs was used to derive five logistic regression models: (i) one novel WCT differentiation model (i.e., VCG Model), (ii) three previously developed WCT differentiation models (i.e., WCT Formula, VT Prediction Model, and WCT Formula II), and (iii) one “all‐inclusive” model (i.e., Hybrid Model). A separate validation cohort of paired WCT and baseline ECGs was used to trial and compare each model''s performance.ResultsThe VCG Model, composed of WCT QRS duration, baseline QRS duration, absolute change in QRS duration, X‐lead QRS amplitude change, Y‐lead QRS amplitude change, and Z‐lead QRS amplitude change, demonstrated effective WCT differentiation (area under the curve [AUC] 0.94) for the derivation cohort. For the validation cohort, the diagnostic performance of the VCG Model (AUC 0.94) was similar to that achieved by the WCT Formula (AUC 0.95), VT Prediction Model (AUC 0.91), WCT Formula II (AUC 0.94), and Hybrid Model (AUC 0.95).ConclusionCustom calculations derived from mathematically synthesized VCG signals may be used to formulate an effective means to differentiate WCTs automatically.     

The provision of a time-critical elective surgical service during the COVID-19 Crisis: a UK experience

IntroductionWith the emergence of the COVID-19 pandemic, all elective surgery was temporarily suspended in the UK, allowing for diversion of resource to manage the anticipated surge of critically unwell patients. Continuing to deliver time-critical surgical care is important to avoid excess morbidity and mortality from pathologies unrelated to COVID-19. We describe the implementation and short-term surgical outcomes from a system to deliver time-critical elective surgical care to patients during the COVID-19 pandemic.Materials and methodsA protocol for the prioritisation and safe delivery of time-critical surgery at a COVID-19 ‘clean’ site was implemented at the Nuffield Health Exeter Hospital, an independent sector hospital in the southwest of England. Outcomes to 30 days postoperatively were recorded, including unplanned admissions after daycase surgery, readmissions and complications, as well as the incidence of perioperative COVID-19 infection in patients and staff.ResultsA total of 128 surgical procedures were performed during a 31-day period by a range of specialties including breast, plastics, urology, gynaecology, vascular and cardiology. There was one unplanned admission and and two readmissions. Six complications were identified, and all were Clavien-Dindo grade 1 or 2. All 128 patients had preoperative COVID-19 swabs, one of which was positive and the patient had their surgery delayed. Ten patients were tested for COVID-19 postoperatively, with none testing positive.ConclusionThis study has demonstrated the implementation of a safe system for delivery of time-critical elective surgical care at a COVID-19 clean site. Other healthcare providers may benefit from implementation of similar methodology as hospitals plan to restart elective surgery.     

Anterior shear of spinal motion segments. Kinematics, kinetics, and resultant injuries observed in a porcine model.

STUDY DESIGN: A basic study of 56 porcine specimens in anterior shear loading. OBJECTIVES: To determine some modulators of the biomechanics of spinal motion segments exposed to acute shear loading and to identify the resultant injuries. SUMMARY OF BACKGROUND DATA: Most research on spinal injury mechanisms has focused on compressive loading, leaving a void in understanding of the effect of shear loading on origin of injury. METHODS: Cervical spines (n = 56) of domestic pigs (6 months old) were loaded to failure in a specially designed jig that restricted their motion to primarily the shear plane. The specimens were tested at load rates of 100 N/sec or 10,810 N/sec and either in a flexed or neutral posture. In addition, the function of the individual structures of the motion segment were determined by serial dissection forming three groups: whole specimens, specimens with no posterior ligaments, and specimens with no posterior ligaments or facet joints. Load-deformation curves were collected using analog-to-digital sampling rates of 50 and 100 Hz. The mode of failure was then documented through systematic dissection of the specimen and/or radiology techniques. Modeling approaches were then used to gain insight into the failure mechanisms. RESULTS: Dynamic loading (10,810 N/sec) and flexion of the specimens were found to increase the ultimate load at failure when compared with quasistatic loading (100 N/sec) and neutral postures. The disc resisted up to 70% of an applied load, with the pars interarticularis responsible for only 30% of the load. Nonetheless, the pars was the primary site of failure. Furthermore, higher load rates also caused endplate avulsion, specifically in the lateral borders of the anulus. CONCLUSIONS: The porcine model appears to reproduce injuries found in the data available on human lumbar material. Fractures in the pars interarticularis may not greatly weaken the joint, given the dominant role of the disc, but compromise its normal kinematics. Clinically, this may explain the occurrence of pars fractures, without total disability.     

Impact of Prophylactic Central Neck Lymph Node Dissection on Early Recurrence in Papillary Thyroid Carcinoma

Background  

Although the role of prophylactic central neck lymph node dissection (CNLD) in the treatment of papillary thyroid carcinoma (PTC) is controversial, many surgeons perform routine prophylactic CNLD. The present study compares local recurrence rates in PTC patients undergoing total thyroidectomy with and without prophylactic CNLD.     

18F‐fluorodeoxyglucose positron emission tomography imaging in brain tumours: The Western Australia positron emission tomography/cyclotron service experience

¹⁸F‐fluorodeoxyglucose positron emission tomography (FDG‐PET) scans in the first 49 patients referred with either possible brain tumour or brain tumour recurrence were reviewed. FDG‐PET imaging was reported with reference to anatomical imaging. Based on the report the FDG study was classified as either positive or negative for the presence of tumour. Thirty‐eight cases were included in the analysis, 21 having pathological data and 17 with diagnostic clinical follow up. Eleven were excluded, as they had inadequate follow‐up data. Of the 21 cases with pathology, 18 were shown to have tumour. In this group there were five false‐negative scans and two false‐positive PET scans. Seventeen cases were assessed by clinical follow up, nine were considered to have been tumour. There were two false negatives with one false positive. The overall sensitivity, specificity and positive and negative predictive values were 74, 73, 87 and 53% respectively. This is similar to figures previously quoted in published work. Despite relatively limited numbers, the utility of FDG PET imaging in our hands is similar to published reports. With a positive predictive value of 87%, a positive FDG study indicates a high likelihood that there is brain tumour present. A negative study does not exclude the presence of tumour.     

Changes in lumbar lordosis modify the role of the extensor muscles

Study Design. Fiber angles of longissimus thoracis and iliocostalis lumborum at L3 were documented in vivo, using high resolution ultrasound, with the lumbar spine in neutral curve and when fully flexed.

Objectives. To evaluate the effect of changes in lumbar curvature on the mechanics of these muscles.

Background. Full flexion modifies the failure tolerance of the lumbar spine, determines the load distribution among muscle and passive tissues, and modulates the types of tissue damage that occur. Related to this issue are the possible changes in muscle line of action with full flexion which changes the ability of the spine to support shear loads.

Methods. Nine normal men and 5 normal women were scanned in three positions: (1) an upright standing posture; (2) with the hips flexed to approximately 30° and the spine fully flexed; (3) hips flexed but the spine returned to a neutral curvature.

Results. Mean longissimus/iliocostalis fiber angles for upright standing, hips flexed-spine flexed, and hips flexed-spine neutral lordosis were 25.7°, 10.7° and 28.3°, respectively.

Conclusions. Anterior shear load on the lumbar spine has been recently shown to be highly related to the risk of reporting a back injury. Bending forward allowing the spine to fully flex changes the line of action of the largest lumbar extensor muscles compromising their role to support anterior shear forces.Relevance

Fiber angles of longissimus thoracis and iliocostalis lumborum were documented with high resolution ultrasound at L3, with the spine in neutral curvature and fully flexed. Full lumbar flexion changes the line of action of these muscle compromising their role to support anterior shear forces on the spine – anterior shear forces have been recently documented to be highly related to the risk of reporting a back injury.     

hsp70, hsp32, and grp78 are increased in thermally injured skin with and without antithrombin(human) concentrate infusion

An acquired deficiency of antithrombin (AT), an anti-inflammatory protein, develops in patients with thermal injuries. Skin thermotolerance is regulated by heat shock protein (hsp) genes. hsp70, hsp32, hsp27, and glucose-regulated protein78 (grp78) were studied in burned and unburned human skin to determine whether correction of the AT deficiency modulated the intensity of expression of these proteins. Fifty-four human skin samples were prepared by Western blot analysis: 11 unburned and 22 burned control skin samples and 7 unburned and 14 burned skin samples from patients treated with AT(Human), or AT(H). The intensity of hsp32 expression in burned AT(H)-treated skin (P < .001) and in burned control skin (P < .01) was significantly increased compared with unburned control skin. The intensity of expression of hsp70 was statistically significant in burned AT(H)-treated skin compared with unburned control skin (P < .02), as was that of grp78 (P < .01). Thermally injured skin with or without AT(H) treatment had an increased expression of hsp70, hsp32, and grp78 compared with unburned control skin.     

Abnormal cervical cytology leading to the diagnosis of gastric cancer

There have been nine cases reported in the English literature in which the finding of malignant cells on cervical/vaginal cytology led to the diagnosis of primary gastric cancer. We report on a patient with gastric carcinoma, metastatic to the cervix, in which the diagnosis was suspected by the finding of signet ring cells on a Papanicolaou smear of the cervix. Prior to treatment of this patient, concordance of signet ring carcinoma on cervical and ascitic fluid cytology and on cervical and gastric biopsies was documented; this has not been reported previously. Thirty-four additional cases of gastric carcinoma metastatic to the cervix are reviewed. This paper is presented to remind the clinician that, however rare, metastases from the gastrointestinal tract to the uterine cervix do occur.