A5038979638- Cardiac electrophysiology and arrhythmias
- Cardiac Arrhythmias and Treatments
- ECG Monitoring and Analysis
- Cardiac Imaging and Diagnostics
- Cardiac pacing and defibrillation studies
- Ion channel regulation and function
- Heart Rate Variability and Autonomic Control
- Antifungal resistance and susceptibility
- Advanced MRI Techniques and Applications
- Neuroscience and Neural Engineering
- Fungal Infections and Studies
- Cardiomyopathy and Myosin Studies
- Cardiovascular Function and Risk Factors
- Dialysis and Renal Disease Management
- Multiple Myeloma Research and Treatments
- Respiratory viral infections research
- EEG and Brain-Computer Interfaces
- Nail Diseases and Treatments
- Clostridium difficile and Clostridium perfringens research
- Peptidase Inhibition and Analysis
- Mycobacterium research and diagnosis
- stochastic dynamics and bifurcation
- Non-Invasive Vital Sign Monitoring
- HIV-related health complications and treatments
- Plant Pathogens and Fungal Diseases
University of Arkansas for Medical Sciences
2015-2022
Conway Regional Health System
2021
University of Arkansas at Fayetteville
2020
University of Arkansas Medical Center
2018-2019
Office of Infectious Diseases
2017
National Institutes of Health
2016
National Center for Advancing Translational Sciences
2016
University of Utah
1981-2015
DaVita Clinical Research (United States)
2011-2014
Mayo Clinic
2013
The Karhunen-Loeve technique of random process representation was investigated as a method quantitatively characterizing body surface potential maps. One hundred ninety-two lead maps from 124 normal subjects and 97 patients with independently documented heart disease were used in the study. Each map frame QRS ST-T 34 test set represented linear sum orthonormal distributions derived covariance matrix estimated all frames 221 training A 16:1 reduction spatial data achieved rms errors 45 21...
A theoretical model of the T wave based on sequence depolarization and multiple action potentials in appropriate time phase has been presented. The methods used to derive waves loops from QRS complex experimental animals have described, derived were closely similar recorded these animals. findings indicate utility understanding normal suggest it may be useful accounting for abnormal waves.
Body surface potential maps provide more detailed regional cardiac electrophysiologic information than the standard electrocardiogram. We performed a large-scale study of normal population to form comparison base for evaluation clinical utility this technique. analyzed body from 1113 subjects 10 80 years old detail map features as function age, sex, and habitus. Maps were by visual inspection spatial temporal data reduction technique that allows statistical features. On average, both QRS...
The use of limited leads for estimating total body surface potential distributions was investigated as a practical solution to the problem associated with extensive electrocardiographic sampling used in mapping. Two practical, lead sets 32 each were derived and contrasted set 30 precordial similar those ST-segment QRS mapping infarct size, nine simulating conventional 12-lead examinations. two arrays, one which excluded posterior sites recumbent patients, showed little difference ability...
Canine ventricular refractory periods were measured during test site drive, drive of single ectopic sites, fusion from two and an the site. Refractory period duration was dependent on driving modes employed. 2.63 +/- 0.73%, 3.42 0.87%, 3.54 100%, 4.68 1.36% (mean SD) shorter sites 2, 4, 6, 40-60 mm, respectively, than drive. During average 2.44 1.04 msec less a (P 0.005). When activation, induced by located within 4 mm or site, also significantly 0.05). as much 10 when occurred 1 their...
The electrophysiologic basis of ischemic ST-segment displacement was investigated in 40 open chest dogs.Epicardial and subendocardial electrograms were recorded with direct current coupled amplifiers during partial complete coronary artery occlu- sion.The time course magnitude DC potential changes, the effects on potentials heart rate ischemia investigated.TQ segment depression, representing loss resting membrane potential, found to be consistent most specific mechanism "ST displacement" due...
We measured QRST deflection areas in cardiac surface electrograms of dogs and determined their relation to changes refractory period induced by localized myocardial warming. Refractory were highly correlated with an average correlation 0.95 over multiple activation sequences. For a single sequence, change was also ST-T area, but sequences this reduced the pooled variance 18 times greater than that area. No between area absolute value various sites evident. Findings suggest particular set...
The physiological basis of serial T-wave abnormalities associated with myocardial infarction was studied. After coronary artery ligation in dogs, ventricular functional refractory periods (FRPs) were measured at five to eight epicardial, intramural, and endocardial sites. FRPs during acute ischemia shortened an average 26 msec. 24 72 hr after msec longer ischemic than nonischemic Alterations recovery times analyzed terms a repolarization model which related the form action potential...
The relation between nonuniform epicardial activation and ventricular repolarization properties was studied in 14 pentobarbital anesthetized dogs with a computer model. In 11 dogs, isochrone maps of sequence were constructed from electrograms recorded the pulmonary conus 64 electrodes on an 8 X grid 2-mm electrode separation. heart paced multiple sites periphery array. Uniformity estimated times at test their eight neighboring sites. Acceleration shortened deceleration prolonged refractory...
Distributions of QRS, ST-T and QRST areas 192 lead body surface ECG's were measured in dogs for multiple activation orders. Qualitatively, the distributions area found to be strikingly similar over all orders contrast QRS or areas. Quantitative results showed that variability was consistently less than those either ST-T. The factor responsible deflection is ventricular sequence while are both recovery properties. Since total largely independent it likely quantity an index significance this...
Isopotential mpas based on 192-200 body surface electrocardiograms were obtained for 20 dogs during multiple patterns of ventricular activation. The purposes the study to determine whether cardiac location events responsible potentials had a recognizable influence potential and examine electrical occurring simultaneously in regions. Substantially different effects activity various regions evidenced by maxima minima isopotential lines early portions excitation initiated at sites. Simultaneous...
A patient with asplenia and multiple red blood cell transfusions acquired babesiosis infection Babesia divergens–like/MO-1 organisms not microti, the common United States species. He had no known tick exposure. This is believed to be first transfusion-transmitted case fifth documented of B. infection.
The survival benefit of combination antifungal therapy for invasive mucormycosis (IM) in patients with hematologic malignancy (HM) and hematopoietic cell transplant (HCT) is not well defined.This multicenter, retrospective study included HM HCT recipients proven or probable IM between January 1, 2007 December 31, 2017 from 10 centers across North America.Sixty-four (n = 47) 17) defined by 2008 European Organization Research Treatment Cancer/Mycoses Study Group (EORTC/MSG) consensus...
Three-dimensional membrane-based simulations of action potential propagation in ventricular myocardium were performed. Specifically, the effects intramural rotation fiber axes and inhomogeneous conductivity on timing pattern epicardial activation examined. Models built, with approximately 400,000 microscopic elements arranged rectangular parallelepipeds each model. Simulations used nonlinear Ebihara Johnson membrane equations for fast sodium current. Constructed models had histological...