Narrow QRS Tachycardia with Alternate Wide QRS Beats: What is the Mechanism?

A 44-year old lady underwent electrophysiology study for recurrent palpitations and documented narrow QRS regular tachycardia. The baseline ECG showed subtle preexcitation that was easily manifest on atrial pacing. The retrograde atrial activation sequence during ventricular pacing was eccentric suggesting retrograde conduction over the accessory pathway. A regular narrow QRS tachycardia with cycle length 280 ms was easily inducible on programmed atrial stimulation. The earliest ventricular activation during sinus rhythm & atrial pacing, and the retrograde atrial activation during ventricular pacing & tachycardia were diagnostic of left free wall accessory pathway and orthodromic atrioventricular reciprocating tachycardia (AVRT). During an episode of tachycardia, an ablation catheter was placed in the region of the lateral mitral annulus using retrograde trans-aortic approach. Once the ablation catheter was stabilized in that region, an interesting change in the AVRT was seen with appearance of wide QRS complexes of right bundle branch block (RBBB) morphology and left axis deviation in the alternate beats (Figure 1). The atrial activation sequence during both narrow and wide QRS beats was same with earliest activation in the distal coronary sinus. What is the mechanism of the alternate wide QRS beats during the AVRT

On optimal bidding in sequential procurement auctions

a b s t r a c t We investigate the problem of optimal bidding for a firm that in each period procures items to meet a random demand by participating in a finite sequence of auctions. We develop a new model for a firm where its item valuation derives from the sale of the acquired items via their demand distribution, sale price, acquisition cost, salvage value and lost sales. We establish monotonicity properties for the value function and the optimal dynamic bid strategy and we present computations

Guillain-Barré syndrome: a rare association of COVID-19 pneumonia at presentation

COVID-19 is a global pandemic which has varied array of symptoms. A neurotropic presentation has also been described of which the most common is stroke. In this brief communication we report a case of COVID-19 who presented to our hospital with features suggestive of Guillain-Barré syndrome. A 76 year old male presented with chief complains of weakness in both lower limbs. On detailed examination the patient had LMN type quadriparesis without sensory involvement. Diagnosis of GBS was confirmed by CSF and NCV studies and other cases of quadriparesis were ruled out by appropriate investigations and treatment of the same was started. Respiratory examination revealed bilateral basal crepitations and CXR revealed B/L lower zone haziness so a secondary diagnosis of B/L Atypical Pneumonitis suspected COVID-19 was kept. A COVID-19 RTPCR turned out to be negative initially. However, looking at respiratory signs and symptoms along with increase in inflammatory markers a repeat COVID RTPCR was planned which turned out to be positive. Patient was further managed on the line of COVID-19 pneumonitis. He responded well to the treatment and is now asymptomatic on follow up. Nervous system involvement in COVID-19 may have been grossly underestimated. Over the course of this pandemic, an increasing number of COVID-19 patients are being reported with neurological complications. Physicians should be aware of atypical presentation where patient complained of weakness first and had respiratory symptoms later as in our case where early detection of atypical presentations help in better management

Analysis and design optimization of enhanced swing CMOS LC oscillators based on a phasor based approach

Analysis and design optimization of enhanced swing, low power CMOS LC oscillators is presented. A phasor analysis based approach for determining the amplitude and phase noise of these oscillators is used. MOSFET operation in cut-off, linear and saturation regions is included. The calculated steady state output amplitude and phase noise from this analysis are in good agreement with Cadence Spectre simulations for different bias conditions. Application of this analysis to the design optimization of LC oscillators is demonstrated.Keywords: ISF, Phasor model, PPV, Spectrum conversion, Design oriented analysis, Voltage biased, Enhanced swing oscillator, Oscillator design, Amplitude analysis, X-coupled, Phase noise, Colpitts oscillator, LC oscillator, Design optimizatio

350 mV, 5 GHz Class-D Enhanced Swing Differential and Quadrature VCOs in 65 nm CMOS

A new enhanced swing class-D VCO which operates from a supply voltage as low as 300 mV is presented. The architectural advantages are described along with an analysis for the oscillation frequency. Prototype differential and quadrature variants of the proposed VCO have been implemented in a 65 nm RF CMOS process with a 5 GHz VCO oscillation frequency. At a 350 mV supply, the measured phase noise performance for the quadrature VCO with a 5% tuning range is -137.1 dBc/Hz at 3 MHz offset with a power dissipation of 2.1 mW from a 0.35 V supply. The highest resulting figure-of-merit (FoM) is 198.3 dBc/Hz.©2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works

Antimicrobial Stewardship Training for Infectious Diseases Fellows: Program Directors Identify a Curriculum Need

A needs assessment survey of infectious diseases (ID) training program directors identified gaps in educational resources for training and evaluating ID fellows in antimicrobial stewardship. An Infectious Diseases Society of America-sponsored core curriculum was developed to address that need

Use of Novel Strategies to Develop Guidelines for Management of Pyogenic Osteomyelitis in Adults: A WikiGuidelines Group Consensus Statement.

Importance Traditional approaches to practice guidelines frequently result in dissociation between strength of recommendation and quality of evidence. Objective To construct a clinical guideline for pyogenic osteomyelitis management, with a new standard of evidence to resolve the gap between strength of recommendation and quality of evidence, through the use of a novel open access approach utilizing social media tools. Evidence Review This consensus statement and systematic review study used a novel approach from the WikiGuidelines Group, an open access collaborative research project, to construct clinical guidelines for pyogenic osteomyelitis. In June 2021 and February 2022, authors recruited via social media conducted multiple PubMed literature searches, including all years and languages, regarding osteomyelitis management; criteria for article quality and inclusion were specified in the group's charter. The GRADE system for evaluating evidence was not used based on previously published concerns regarding the potential dissociation between strength of recommendation and quality of evidence. Instead, the charter required that clear recommendations be made only when reproducible, prospective, controlled studies provided hypothesis-confirming evidence. In the absence of such data, clinical reviews were drafted to discuss pros and cons of care choices. Both clear recommendations and clinical reviews were planned with the intention to be regularly updated as new data become available. Findings Sixty-three participants with diverse expertise from 8 countries developed the group's charter and its first guideline on pyogenic osteomyelitis. These participants included both nonacademic and academic physicians and pharmacists specializing in general internal medicine or hospital medicine, infectious diseases, orthopedic surgery, pharmacology, and medical microbiology. Of the 7 questions addressed in the guideline, 2 clear recommendations were offered for the use of oral antibiotic therapy and the duration of therapy. In addition, 5 clinical reviews were authored addressing diagnosis, approaches to osteomyelitis underlying a pressure ulcer, timing for the administration of empirical therapy, specific antimicrobial options (including empirical regimens, use of antimicrobials targeting resistant pathogens, the role of bone penetration, and the use of rifampin as adjunctive therapy), and the role of biomarkers and imaging to assess responses to therapy. Conclusions and Relevance The WikiGuidelines approach offers a novel methodology for clinical guideline development that precludes recommendations based on low-quality data or opinion. The primary limitation is the need for more rigorous clinical investigations, enabling additional clear recommendations for clinical questions currently unresolved by high-quality data

On optimal bidding in sequential procurement auctions

We investigate the problem of optimal bidding for a firm that in each period procures items to meet a random demand by participating in a finite sequence of auctions. We develop a new model for a firm where its item valuation derives from the sale of the acquired items via their demand distribution, sale price, acquisition cost, salvage value and lost sales. We establish monotonicity properties for the value function and the optimal dynamic bid strategy and we present computations. © 2012 Elsevier B.V. All rights reserved