A5074500983- Cardiac electrophysiology and arrhythmias
- Acute Kidney Injury Research
- Ion channel regulation and function
- Cardiovascular and exercise physiology
- Cardiac Imaging and Diagnostics
- Advanced MRI Techniques and Applications
- Neuroscience and Neural Engineering
- Traumatic Brain Injury and Neurovascular Disturbances
- Cardiovascular Function and Risk Factors
- Electrochemical Analysis and Applications
- Chronic Kidney Disease and Diabetes
- Cardiovascular Effects of Exercise
- Sports Performance and Training
- Organ Donation and Transplantation
- HIV Research and Treatment
- Cardiac Arrhythmias and Treatments
- Cardiac pacing and defibrillation studies
- Acute Ischemic Stroke Management
- Muscle metabolism and nutrition
- Heart Rate Variability and Autonomic Control
- Congenital Heart Disease Studies
- Muscle activation and electromyography studies
- Neuroscience and Neuropharmacology Research
- Acute Myocardial Infarction Research
- Neonatal Health and Biochemistry
University of Calgary
2012-2025
Sahlgrenska University Hospital
2019-2025
Libin Cardiovascular Institute of Alberta
2017
Karolinska Institutet
1991-2016
Karolinska University Hospital
1990-2016
Danderyds sjukhus
2016
Episcopal Divinity School
2016
Calgary Laboratory Services
2015
Clinica Santa Maria
2015
Isala
2015
Abstract —We have developed a mathematical model of the human atrial myocyte based on averaged voltage-clamp data recorded from isolated single myocytes. Our consists Hodgkin-Huxley–type equivalent circuit for sarcolemma, coupled with fluid compartment model, which accounts changes in ionic concentrations cytoplasm as well sarcoplasmic reticulum. This formulation can reconstruct action potential that are representative recordings majority cells our laboratory and therefore provides...
<i>Background: </i>Magnetic resonance (MR) imaging is frequently used to diagnose arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). However, the reliability of various MR features for diagnosing ARVC/D unknown. The purpose this study was determine which morphologic have greatest interobserver ARVC/D. <i>Methods: </i>Forty-five sets films cardiac images were sent 8 radiologists and 5 cardiologists with experience in field. There 7 cases definite as...
Background and Purpose— There is uncertainty regarding the best way for patients outside of endovascular-capable or Comprehensive Stroke Centers (CSC) to access endovascular treatment acute ischemic stroke. The role nonendovascular-capable Primary (PSC) that can offer thrombolysis with alteplase but not unclear. A key question whether average benefit greater early at closest PSC before transportation CSC (Drip ‘n Ship) bypass direct transport (Mothership). Ideal options were mapped based on...
T-type (CaV3.1/CaV3.2) Ca(2+) channels are expressed in rat cerebral arterial smooth muscle. Although present, their functional significance remains uncertain with findings pointing to a variety of roles.This study tested whether CaV3.2 mediate negative feedback response by triggering sparks, discrete events that initiate hyperpolarization activating large-conductance Ca(2+)-activated K(+) channels.Micromolar Ni(2+), an agent selectively blocks but not CaV1.2/CaV3.1, was first shown...
The effect of slow intravenous infusion contrast medium (CM) (1600 mg I/kg body weight) on cortical blood flow (BF) and medullary BF in rat kidneys was investigated by laser-Doppler flowmetry either renal cortex or exposed papillas (inner medulla). evaluated after ioxaglate, iohexol, ioxithalamate. Mannitol Ringer's solution were used as control substances. examined iopamidol, ioxithalamate, mannitol. measured continuously during a 30-minute period 60-minute experimental period, starting...
The Purkinje system is the fast conduction network of heart which couples to myocardium at discrete sites called Purkinje-Myocyte Junctions (PMJs). However, distribution and number PMJs remains elusive, as does whether a particular PMJ functional. We hypothesized that plays role during reentry functional affect dynamics. used computer finite element model rabbit ventricles in we varied PMJs. Sustained, complex was induced by applying an electric shock maintaining arrhythmia assessed...
Background Arrhythmogenic cardiomyopathy is an inherited heart muscle disorder leading to ventricular arrhythmias and failure, mainly as a result of mutations in cardiac desmosomal genes. Desmosomes are cell-cell junctions mediating adhesion cardiomyocytes; however, the molecular cellular mechanisms underlying disease remain widely unknown. Desmocollin-2 cadherin serving anchor molecule required reconstitute homeostatic intercellular with desmoglein-2. Cardiac specific lack desmoglein-2...
Abstract Background and Aims Transcatheter pulmonary valve implantation (TPVI) is indicated to treat right-ventricular outflow tract (RVOT) dysfunction related congenital heart disease (CHD). Outcomes of TPVI with the SAPIEN 3 that are insufficiently documented were investigated in EUROPULMS3 registry 3-TPVI. Methods Patient-related, procedural, follow-up outcome data retrospectively assessed this observational cohort from 35 centres 15 countries. Results Data for 840 consecutive patients...
A noninvasive magnetic resonance imaging (MRI) method to assess the distribution of perfusion and metabolic demand (Q˙/V˙o 2 ) in exercising human skeletal muscle is described. This combines two MRI techniques that can provide accurate multiple localized measurements Q˙/V˙o during steady-state plantar flexion exercise. The first technique, 31 P chemical shift imaging, permits acquisition comparable phosphorus spectra from voxels simultaneously. Because phosphocreatine (PCr) depletion...
The effect of i.v. injection contrast media (CM, 1,600 mg I/kg b.w.) on proximal and distal tubular hydrostatic pressure (PTHP, DTHP) in the rat was investigated using a micropuncture technique. PTHP DTHP after diatrizoate, iohexol, ioxaglate, or mannitol returned to control values within approximately 20 min. However, following iotrolan still elevated above levels 35 min while remained throughout experiment (50 min). Iotrolan has lower osmotic potential than other CM when given equivalent...
Dilated cardiomyopathy (DCM) leads to dilation of the cardiac chambers and congestive heart failure. Recent reports have associated mutations in SCN5A gene, which codes for major sodium channel Nav1.5, with DCM. Although DCM is most common form cardiomyopathy, no animal studies established this functional connection.We produced transgenic mice that ectopically express transcriptional repressor Snail heart. These animals display severe DCM, ECG abnormalities, conduction defects, revealed by...
An imaging system suitable for recordings from Langendorff-perfused rat hearts using the voltage-sensitive dye 4-[β-[2-(di- n-butylamino)-6-naphthyl]vinyl]pyridinium (di-4-ANEPPS) has been developed. Conduction velocity was measured under hyper- and hypokalemic conditions, as well at physiological reduced temperature. Elevation of extracellular [K + ] to 9 mM 5.9 caused a slowing conduction 0.66 ± 0.08 0.43 0.07 mm/ms (35%), reduction temperature 32°C 37°C 0.64 0.46 0.05 (28%). Ventricular...
Eight healthy men performed supine one‐legged training on a bicycle ergometer 45 min per leg four times week for 4 week. The and lower body were inside pressure chamber, the opening of which was sealed at level crotch. One trained with impeded blood flow (I‐leg), induced by an increased (50 mmHg) chamber pressure, highest tolerable intensity. contralateral same power under normal (N‐leg). Before after biopsies taken from vastus lateralis both legs maximal exercise tests executed legs....
Diabetes mellitus is a growing epidemic with severe cardiovascular complications. Although much known about mechanical and electrical cardiac dysfunction in diabetes, few studies have investigated propagation of the signal diabetic heart associated changes intercellular gap junctions. This study was designed to investigate these issues, using hearts from control rats. Diabetic conditions were induced by streptozotocin (STZ), given i.v. 7-14 days before experiments. Optical mapping...
The effects of slow (10 min) i.v. infusions contrast media (CM, 1 600 mg I/kg b.w.) on single nephron glomerular filtration rate (SNGFR) in the rat kidney were investigated using a micropuncture technique. Diatrizoate, iohexol, or ioxaglate did not change SNGFR, although tendency towards transient suppression was seen during infusion phase. Iotrolan infusion, however, decreased SNGFR (p < 0.05) and value still remained below control 25 min after start infusion. is nonionic dimeric CM has...
Healthy young men executed supine one-legged cycle training four times per week for 4 wk with legs and the ergometer inside a pressure chamber, opening of which was sealed by rubber membrane at level crotch. Each session started one leg under ischemic conditions induced increased chamber (50 mmHg) highest intensity tolerable 45 min. Then other trained same power profile but normal atmospheric pressure. Before after period, both exercise tests muscle biopsies were taken from vastus lateralis....
Fitting parameter sets of non-linear equations in cardiac single cell ionic models to reproduce experimental behavior is a time consuming process. The standard procedure adjust maximum channel conductances action potentials (APs) recorded isolated cells. However, vastly different parameters can produce similar APs. Furthermore, even with an excellent AP match case cell, tissue behaviour may be very different. We hypothesize that this uncertainty reduced by additionally fitting membrane...
To study short and long term results after surgical closure of isolated ventricular septal defects (VSDs) from 1976 to 1996, especially in relation changes preoperative evaluation during this period.Retrospective study.Tertiary referral centre for paediatric cardiac care.All children under 18 years age who had corrective surgery VSD between 1996.Preoperative evaluation, indications surgery, diagnostic errors, early late results.A significant decrease the use invasive studies favour...
Two independent mathematical models of the electrophysiology human atrial cell have been published. Although these two are based on very similar data, they can result in some apparently contradictory findings, which fundamental importance to and pharmacology. In particular, simulations with given rise different conclusions regarding role rapidly activating sustained outward K+ current, Isus, determining action–potential duration. Different rate dependence action potential also this paper, we...