Scholars@Duke
Augustus Oliver Grant

Augustus Oliver Grant

Professor of Medicine
Medicine, Cardiology
grant007@mc.duke.edu
Duke Box 3504, Durham, NC 27710
2301 Erwin Road, 7th Floor, Room #7407, Durham, NC 27710

Selected Publications

Catheter ablation of atrial fibrillation in patients with heart failure and preserved ejection fraction.

Journal Article Heart Rhythm · May 2018 BACKGROUND: Few studies have examined outcomes of catheter ablation for atrial fibrillation (AF) in patients with heart failure (HF) with preserved ejection fraction (HFpEF). OBJECTIVE: The purpose of this study was to compare outcomes of AF ablation in pa ... Full text Link to item Cite

Ranolazine reduces atrial fibrillatory wave frequency.

Journal Article Europace · July 1, 2017 AIMS: Antiarrhythmic medications for the treatment of atrial fibrillation (AF) have limited efficacy and rare but potentially life-threatening side effects. Ranolazine is an antianginal agent that may have antiarrhythmic activity in AF. METHODS AND RESULTS ... Full text Link to item Cite

Amino acids stimulate cholecystokinin release through the Ca2+-sensing receptor.

Journal Article Am J Physiol Gastrointest Liver Physiol · April 2011 Cholecystokinin (CCK) is produced by discrete endocrine cells in the proximal small intestine and is released following the ingestion of food. CCK is the primary hormone responsible for gallbladder contraction and has potent effects on pancreatic secretion ... Full text Link to item Cite

Basic Electrophysiology.

Journal Article Card Electrophysiol Clin · September 2010 Available evidence suggests that the ion channels that generate the normal action potential are also the basis for the arrhythmias that occur in disease states. Therefore, a thorough understanding of the function of the ion channels that generate the actio ... Full text Link to item Cite

The variability of the electrical properties of the pulmonary veins.

Journal Article J Cardiovasc Electrophysiol · September 2009 Full text Link to item Cite

Cardiac ion channels.

Journal Article Circ Arrhythm Electrophysiol · April 2009 Full text Link to item Cite

Ethnicity and arrhythmia susceptibility.

Journal Article J Cardiovasc Electrophysiol · April 2008 Full text Link to item Cite

The influence of cardiograph design and automated algorithms on the incidence and detection of electrode cable reversals in an academic electrocardiogram laboratory.

Journal Article J Electrocardiol · 2008 BACKGROUND: Medical errors have been increasingly identified as a major source of morbidity and mortality in both outpatient and acute care settings. Central to the evaluation of many medical problems, the 12-lead electrocardiogram (ECG) is susceptible to ... Full text Link to item Cite

Inherited arrhythmias: a National Heart, Lung, and Blood Institute and Office of Rare Diseases workshop consensus report about the diagnosis, phenotyping, molecular mechanisms, and therapeutic approaches for primary cardiomyopathies of gene mutations affecting ion channel function.

Journal Article Circulation · November 13, 2007 The National Heart, Lung, and Blood Institute and Office of Rare Diseases at the National Institutes of Health organized a workshop (September 14 to 15, 2006, in Bethesda, Md) to advise on new research directions needed for improved identification and trea ... Full text Link to item Cite

Sodium channel kinetic changes that produce Brugada syndrome or progressive cardiac conduction system disease.

Journal Article Am J Physiol Heart Circ Physiol · January 2007 Some mutations of the sodium channel gene Na(V1.5) are multifunctional, causing combinations of LQTS, Brugada syndrome and progressive cardiac conduction system disease (PCCD). The combination of Brugada syndrome and PCCD is uncommon, although they both re ... Full text Link to item Cite

Effect of blinded peer review on abstract acceptance.

Journal Article JAMA · April 12, 2006 CONTEXT: Peer review should evaluate the merit and quality of abstracts but may be biased by geographic location or institutional prestige. The effectiveness of blinded peer review at reducing bias is unknown. OBJECTIVE: To evaluate the effect of blinded r ... Full text Link to item Cite

Slow sodium channel inactivation and use-dependent block modulated by the same domain IV S6 residue.

Journal Article J Membr Biol · September 2005 Voltage- and/or conformation-dependent association and dissociation of local anesthetic-class drugs from a putative receptor site in domain IV S6 of the sodium channel and slow conformation transitions of the drug-associated channel have been proposed as m ... Full text Link to item Cite

Electrophysiological basis and genetics of Brugada syndrome.

Journal Article J Cardiovasc Electrophysiol · September 2005 Brugada syndrome is a primary arrhythmic syndrome arising in the structurally normal heart. Any proposed mechanism should account for the major features of the syndrome: localization of the ST segment and T-wave changes to the right precordial leads, assoc ... Full text Link to item Cite

Task Force 7: arrhythmias.

Journal Article J Am Coll Cardiol · April 19, 2005 Full text Link to item Cite

Task force 5: Expert testimony and opinions.

Journal Article J Am Coll Cardiol · October 19, 2004 Full text Link to item Cite

Task force 5: Expert testimony and opinions

Journal Article Circulation · October 19, 2004 Full text Cite

Nicotine inhibits voltage-dependent sodium channels and sensitizes vanilloid receptors.

Journal Article J Neurophysiol · April 2004 Nicotine is an alkaloid that is used by large numbers of people. When taken into the body, it produces a myriad of physiological actions that occur primarily through the activation of neuronal nicotinic acetylcholine receptors (nAChRs). We have explored it ... Full text Link to item Cite

Cardiovascular disease in women: are there solutions?

Journal Article Circulation · February 10, 2004 Full text Link to item Cite

Recent advances in the treatment of arrhythmias.

Journal Article Circ J · August 2003 Advances in endocardial mapping techniques and ablation have greatly increased the indications for catheter-ablation of supraventricular arrhythmias. Rate or rhythm control is a valid treatment option for patients with atrial fibrillation; however, all pat ... Full text Link to item Cite

What happens when cardiac Na channel function is compromised? 2. Numerical studies of the vulnerable period in tissue altered by drugs.

Journal Article Cardiovasc Res · March 15, 2003 OBJECTIVE: The fate of an impulse arising from stimulation is determined by the ability of the wave front to recruit sufficient Na channels from adjacent cells. Previous numerical studies of mutant Na channels revealed both the velocity of a conditioning w ... Full text Link to item Cite

What happens when cardiac Na channels lose their function? 1--numerical studies of the vulnerable period in tissue expressing mutant channels.

Journal Article Cardiovasc Res · January 2003 OBJECTIVE: The vulnerable period (VP) defines an interval during which premature impulses can trigger reentrant arrhythmias leading to ventricular fibrillation and sudden death. The mechanistic basis of the success or failure of impulse propagation during ... Full text Link to item Cite

Long QT syndrome, Brugada syndrome, and conduction system disease are linked to a single sodium channel mutation.

Journal Article J Clin Invest · October 2002 The function of the 12 positive charges in the 53-residue III/IV interdomain linker of the cardiac Na(+) channel is unclear. We have identified a four-generation family, including 17 gene carriers with long QT syndrome, Brugada syndrome, and conduction sys ... Full text Link to item Cite

Molecular biology of sodium channels and their role in cardiac arrhythmias.

Journal Article Am J Med · March 2001 The sodium channel is an integral membrane protein that plays a central role in conduction of the cardiac impulse in working cardiac myocytes and cells of the His-Purkinje system. The channel has two fundamental properties, ion conduction and gating. Speci ... Full text Link to item Cite

Block of wild-type and inactivation-deficient cardiac sodium channels IFM/QQQ stably expressed in mammalian cells.

Journal Article Biophys J · December 2000 The role of inactivation as a central mechanism in blockade of the cardiac Na(+) channel by antiarrhythmic drugs remains uncertain. We have used whole-cell and single channel recordings to examine the block of wild-type and inactivation-deficient mutant ca ... Full text Link to item Cite

Abnormal cardiac Na(+) channel properties and QT heart rate adaptation in neonatal ankyrin(B) knockout mice.

Journal Article Circ Res · March 3, 2000 The cytoskeleton of the cardiomyocyte has been shown to modulate ion channel function. Cytoskeletal disruption in vitro alters Na(+) channel kinetics, producing a late Na(+) current that can prolong repolarization. This study describes the properties of th ... Full text Link to item Cite

beta-Adrenergic action on wild-type and KPQ mutant human cardiac Na+ channels: shift in gating but no change in Ca2+:Na+ selectivity.

Journal Article Cardiovasc Res · May 1999 OBJECTIVE: Prior studies of the modulation of the Na+ current by sympathetic stimulation have yielded controversial results. Separation of the Na+ and Ca2+ currents poses a problem in myocyte preparations. The gating of cloned Na+ channels is different in ... Full text Link to item Cite

Selecting an antiarrhythmic agent for atrial fibrillation should be a patient-specific, data-driven decision.

Journal Article Am J Cardiol · October 16, 1998 Selecting an antiarrhythmic agent for atrial fibrillation (AF) should be a patient-specific decision. When possible, it should be based on sound rationale and available clinical data. This article details many of the thought processes that must go into thi ... Full text Link to item Cite

Mechanisms of atrial fibrillation and action of drugs used in its management.

Journal Article Am J Cardiol · October 16, 1998 Drugs remain the mainstay of treatment of patients with atrial fibrillation (AF). An understanding of the mechanisms of AF and of atrioventricular (AV) conduction provides a basis for the understanding of the mechanisms of antiarrhythmic drug action. Altho ... Full text Link to item Cite

Multiple effects of KPQ deletion mutation on gating of human cardiac Na+channels expressed in mammalian cells.

Journal Article Am J Physiol Heart Circ Physiol · May 1, 1998 Several aspects of the effect of the KPQ deletion mutation on Na+channel gating remain unresolved. We have analyzed the kinetics of the early and late currents by recording whole cell and single-channel currents in a human embryonic kidney (HEK) cell line ... Full text Link to item Cite

Multiple effects of KPQ deletion mutation on gating of human cardiac Na+ channels expressed in mammalian cells

Journal Article American Journal of Physiology - Heart and Circulatory Physiology · May 1, 1998 Several aspects of the effect of the KPQ deletion mutation on Na+ channel gating remain unresolved. We have analyzed the kinetics of the early and late currents by recording whole cell and single-channel currents in a human embryonic kidney (HEK) cell line ... Cite

Emerging class III antiarrhythmic agents: mechanism of action and proarrhythmic potential.

Journal Article Cardiovasc Drugs Ther · April 1997 The goal of developing an antiarrhythmic agent effective against malignant ventricular arrhythmias while maintaining a low side-effect profile remains elusive. The class III drugs amiodarone and sotalol are the best available agents. However, both drugs po ... Full text Link to item Cite

Mechanisms of action of antiarrhythmic drugs: from ion channel blockage to arrhythmia termination.

Journal Article Pacing Clin Electrophysiol · February 1997 Over the past decade, the strategies for arrhythmia management have been in transition. Physical methods to treat arrhythmias, such as ICDs and RF ablation, have undergone considerable refinement and wider application. Ischemic heart disease and congestive ... Full text Link to item Cite

Potentiation of beta-adrenergic signaling by adenoviral-mediated gene transfer in adult rabbit ventricular myocytes.

Journal Article J Clin Invest · January 15, 1997 Our laboratory has been testing the hypothesis that genetic modulation of the beta-adrenergic signaling cascade can enhance cardiac function. We have previously shown that transgenic mice with cardiac overexpression of either the human beta2-adrenergic rec ... Full text Open Access Link to item Cite

The role of inactivation in open-channel block of the sodium channel: studies with inactivation-deficient mutant channels.

Journal Article Mol Pharmacol · December 1996 Inactivation has been implicated as an important determinant of the block of Na+ channel by local anesthetic-class drugs. This proposition has been difficult to examine because agents used to modify inactivation change other channel properties and both ina ... Link to item Cite

Propafenone: an effective agent for the management of supraventricular arrhythmias.

Journal Article J Cardiovasc Electrophysiol · April 1996 Propafenone is a sodium channel blocking antiarrhythmic drug. It also has beta-adrenergic, potassium channel, and weak calcium channel blocking activity. The drug is metabolized in the liver with rates dependent on the debrisoquin phenotype. The saturable ... Full text Link to item Cite

Cardiac transient outward potassium current: a pulse chemistry model of frequency-dependent properties.

Journal Article Am J Physiol · January 1996 Recent voltage-clamp studies of isolated myocytes have demonstrated widespread occurrence of a transient outward current (I(to)) carried by potassium ions. In the canine ventricle, this current is well developed in epicardial cells but not in endocardial c ... Full text Link to item Cite

Basic concepts in cellular cardiac electrophysiology: Part II: Block of ion channels by antiarrhythmic drugs.

Journal Article Pacing Clin Electrophysiol · September 1995 Antiarrhythmic drugs have relative specificity for blocking each of the major classes of ion channels that control the action potential. The kinetics of block is determined by the state of the channel. Those channel states occupied at depolarized potential ... Full text Link to item Cite

Proarrhythmic response to potassium channel blockade. Numerical studies of polymorphic tachyarrhythmias.

Journal Article Circulation · August 1, 1995 BACKGROUND: Prompted by the results of CAST results, attention has shifted from class I agents that primarily block sodium channels to class III agents that primarily block potassium channels for pharmacological management of certain cardiac arrhythmias. R ... Full text Link to item Cite

Cardiac muscarinic potassium channel activity is attenuated by inhibitors of G beta gamma.

Journal Article Circ Res · May 1995 The cardiac muscarinic potassium channel (IK.ACh) is activated by a G protein upon receptor stimulation with acetylcholine. The G protein subunit responsible for activation (G alpha versus G beta gamma) has been disputed. We used G beta gamma inhibitors de ... Full text Link to item Cite

Asymmetrical electrically induced injury of rabbit ventricular myocytes.

Journal Article J Mol Cell Cardiol · May 1995 Strong defibrillation-type electric field stimulation may injure myocytes when transmembrane potentials during the pulse exceed the threshold for membrane permeabilization. The location of injury may depend on intrinsic transmembrane potential or influx of ... Full text Link to item Cite

Relationship between structure and sodium channel blockade by lidocaine and its amino-alkyl derivatives.

Journal Article J Cardiovasc Pharmacol · November 1994 We examined the relationship between the physicochemical properties and the sodium channel-blocking actions of lidocaine and four of its amino-alkyl derivatives. The homologues differ in lipid solubility (log p 2.7-4.1), pKa (6.9-9.0), and molecular weight ... Full text Link to item Cite

Voltage-independent effects of extracellular K+ on the Na+ current and phase 0 of the action potential in isolated cardiac myocytes.

Journal Article Circ Res · September 1994 A rise in [K+]o, by depolarizing the resting membrane potential and partially inactivating the inward Na+ current (INa), is believed to play a critical role in slowing conduction during myocardial ischemia. In multicellular ventricular preparations, elevat ... Full text Link to item Cite

Late Na channels in cardiac cells: the physiological role of background Na channels.

Journal Article Biophys J · July 1994 Two types of the late Na channels, burst and background, were studied in Purkinje and ventricular cells. In the whole-cell configuration, steady-state Na currents were recorded at potentials (-70 to -80 mV) close to the normal cell resting potential. The q ... Full text Link to item Cite

Open Na+ channel blockade: multiple rest states revealed by channel interactions with disopyramide and quinidine.

Journal Article Am J Physiol · May 1994 In voltage-clamp studies of atrial myocytes exposed to disopyramide or quinidine, pulse-train stimulation revealed use-dependent block that increased with increased pulse amplitude. Use-dependent block also became negligible at hyperpolarized holding poten ... Full text Link to item Cite

Kinetics of interaction of disopyramide with the cardiac sodium channel: fast dissociation from open channels at normal rest potentials.

Journal Article J Membr Biol · November 1993 Block of cardiac sodium channels is enhanced by repetitive depolarization. It is not clear whether the changes in drug binding result from a change in affinity that is dependent on voltage or on the actual state of the channel. This question was examined i ... Full text Link to item Cite

pH dependence of kinetics and steady-state block of cardiac sodium channels by lidocaine.

Journal Article Am J Physiol · May 1993 The local anesthetic-class antiarrhythmic drugs produce greater depression of conduction in ischemic compared with normal myocardium. The basis for this relatively selective action is uncertain. A model of the pH-dependent interaction of tertiary amine dru ... Full text Link to item Cite

Optical measurements of transmembrane potential changes during electric field stimulation of ventricular cells.

Journal Article Circ Res · February 1993 We evaluated transmembrane potential changes at the ends of isolated rabbit ventricular myocytes during defibrillation-strength shocks given in the cellular refractory period. The myocytes were stimulated (S1 pulse) to produce an action potential. Then a c ... Full text Link to item Cite

Na channel kinetics remain stable during perforated-patch recordings.

Journal Article Am J Physiol · December 1992 The results of studies on modulation of Na channel function are often difficult to interpret due to time-dependent changes in channel kinetics. Although the "tight-seal" whole cell voltage-clamp technique has proved very useful in studying the properties o ... Full text Link to item Cite

Block and modulation of cardiac Na+ channels by antiarrhythmic drugs, neurotransmitters and hormones.

Journal Article Trends Pharmacol Sci · September 1992 The Na+ channel is an important target for the action of antiarrhythmic drugs. Application of contemporary biophysical, biochemical and molecular biological techniques have added considerably to our knowledge of its structure, function, modulation and bloc ... Full text Link to item Cite

Blockade of cardiac sodium channels. Competition between the permeant ion and antiarrhythmic drugs.

Journal Article J Clin Invest · August 1992 A number of basic and clinical studies suggest that elevation of external sodium concentrations, [Na]o, may reverse the cardiotoxic effect of local anesthetic-class drugs. The mechanisms of reversal are uncertain. The blocking action of lidocaine and disop ... Full text Link to item Cite

Kinetics of interaction of the lidocaine metabolite glycylxylidide with the cardiac sodium channel. Additive blockade with lidocaine.

Journal Article Circ Res · June 1992 The recovery of the sodium channel from blockade by local anesthetic antiarrhythmic drugs is voltage dependent. Recovery from lidocaine-induced blockade is accelerated by hyperpolarization, whereas that from glycylxylidide (GX) blockade has been reported t ... Full text Link to item Cite

Cardiac instability amplified by use-dependent Na channel blockade.

Journal Article Am J Physiol · April 1992 Drugs that exhibit use-dependent Na channel blockade, including antiarrhythmic agents, tricyclic antidepressants, opiate-like analgesics, and cocaine, are linked with an increased susceptibility to cardiac arrhythmias and sudden death. Computer simulations ... Full text Link to item Cite

On the mechanism of action of antiarrhythmic agents.

Journal Article Am Heart J · April 1992 Cardiac arrhythmias arise from disturbances in the functioning of the specific ion channels that normally control excitation or from the functional expression of previously latent channels. Antiarrhythmic agents act by blocking the membrane sodium, potassi ... Full text Link to item Cite

A source of bias in the analysis of single channel data: assessing the apparent interaction between channel proteins.

Journal Article Comput Biomed Res · December 1991 A recent study of single sodium channel currents in neuroblastoma cells suggested interaction between ion channels in close proximity to one another (T. Kiss and K. Nagy, Eur. Biophys. J. 12, 13, 1985). The opening of one channel appeared to affect the lik ... Full text Link to item Cite

The electrophysiology of the cardiac sodium channel.

Journal Article Trends Cardiovasc Med · December 1991 Conduction in most regions of the heart is sustained by transient increases in membrane permeability to Na(+). The application of contemporary biophysical and molecular biologic techniques demonstrates that permeability to Na(+) depends on a distinct prote ... Full text Link to item Cite

Models of drug interaction with the sodium channel.

Journal Article Clin Invest Med · October 1991 The local anesthetic-class of anti-arrhythmic drugs block the inward sodium current in nerve and cardiac muscle. A number of models for the interaction of these drugs with the neuronal sodium channel have been extended to cardiac muscle. The models assume ... Link to item Cite

Blockade of cardiac sodium channels by amitriptyline and diphenylhydantoin. Evidence for two use-dependent binding sites.

Journal Article Circ Res · September 1991 Cardiac toxicity is a frequent manifestation in amitriptyline overdose and is felt to be due, in part, to sodium channel blockade by the drug. Another agent with sodium channel blocking properties, diphenylhydantoin, has been used clinically to reverse car ... Full text Link to item Cite

Proarrhythmic response to sodium channel blockade. Theoretical model and numerical experiments.

Journal Article Circulation · September 1991 BACKGROUND: The use of flecainide and encainide was terminated in the Cardiac Arrhythmia Suppression Trial because of an excess of sudden cardiac deaths in the active treatment group. Such events might arise from reentrant rhythms initiated by premature st ... Full text Link to item Cite

Lidocaine blockade of continuously and transiently accessible sites in cardiac sodium channels.

Journal Article J Mol Cell Cardiol · February 1991 Lidocaine binds to sodium channels in a voltage dependent manner where depolarization enhances block and hyperpolarization relieves block. Voltage--clamp studies demonstrate that there are two components of block: one involving interaction with a binding s ... Full text Link to item Cite

The cardiac sodium channel: a target for antiarrhythmic drug action.

Journal Article Pacing Clin Electrophysiol · November 1990 Full text Link to item Cite

Extracellular pH modulates block of both sodium and calcium channels by nicardipine.

Journal Article Am J Physiol · October 1990 Slowing of the recovery of the Na channel from local anesthetic block at low external pH has been well described. In contrast the Ca channel has been reported not to show such an effect. Because of the absence of this response, a two-site model for the int ... Full text Link to item Cite

Use of ionic currents to identify and estimate parameters in models of channel blockade.

Journal Article Am J Physiol · August 1990 Models of ion channel blockade are frequently validated with observations of ionic currents resulting from electrical or chemical stimulation. Model parameters for some models (modulated receptor hypothesis) cannot be uniquely determined from ionic current ... Full text Link to item Cite

Effects of amiloride on pH regulation in canine cardiac Purkinje fibers.

Journal Article J Pharmacol Exp Ther · July 1990 Myocardial cells utilize membrane transport systems for proton extrusion as well as internal buffers to preserve pH homeostasis. Our laboratory had shown previously that amiloride (0.01-1.0 mM) causes a time- and dose-dependent increase in action potential ... Link to item Cite

An object oriented user interface for analysis of biological data.

Journal Article Comput Biomed Res · February 1990 In a previous paper we described a self-documented file and a collection of general purpose programs or tools that facilitates the management and analysis of biological data. The tools can be specified in a pipeline to accomplish a specific analysis task. ... Full text Link to item Cite

Evolving Concepts of Cardiac Sodium Channel Function

Journal Article Journal of Cardiovascular Electrophysiology · January 1, 1990 Full text Cite

Marked QRS complex abnormalities and sodium channel blockade by propoxyphene reversed with lidocaine.

Journal Article J Clin Invest · November 1989 The opiate analgesic propoxyphene produces cardiac toxicity when taken in overdose. We recently observed a patient with propoxyphene overdose in whom marked QRS widening was reversed by lidocaine. The reversal is apparently paradoxical as both agents block ... Full text Link to item Cite

Blockade of cardiac sodium channels by lidocaine. Single-channel analysis.

Journal Article Circ Res · November 1989 The mechanism of interaction of lidocaine with cardiac sodium channels during use-dependent block is not well defined. We examined the blockade of single cardiac sodium channels by lidocaine and its hydrophobic derivative RAD-242 in rabbit ventricular myoc ... Full text Link to item Cite

Blockade of rabbit atrial sodium channels by lidocaine. Characterization of continuous and frequency-dependent blocking.

Journal Article Circ Res · September 1989 Lidocaine block of the cardiac sodium channel is believed to be primarily a function of channel state. For subthreshold potentials, block is limited to the inactivated state, whereas above threshold, block results from the combination of open- and inactiva ... Full text Link to item Cite

Characterization of concentration- and use-dependent effects of quinidine from conduction delay and declining conduction velocity in canine Purkinje fibers.

Journal Article J Clin Invest · June 1989 The dynamic response of squared conduction velocity, theta 2, to repetitive stimulation in canine Purkinje fibers with quinidine was studied using a double-microelectrode technique. With stimulation, a frequency-dependent monoexponential increase in conduc ... Full text Link to item Cite

Calcium channels reconstituted from the skeletal muscle dihydropyridine receptor protein complex and its alpha 1 peptide subunit in lipid bilayers.

Journal Article Ann N Y Acad Sci · 1989 In the first part of this study, we show that sDHPR and pDHPR preparations reconstituted into lipid bilayers formed on the tips of patch pipettes exhibit two divalent cation-selective conductance levels of 9 and 20 pS, similar in single-channel conductance ... Full text Link to item Cite

Mechanisms of closure of cardiac sodium channels in rabbit ventricular myocytes: single-channel analysis.

Journal Article Circ Res · June 1987 We have examined the kinetics of closure of sodium channels using single-channel recordings in cell-attached and excised membrane patches of rabbit ventricular myocytes. Sodium-channel closure was dependent on membrane potential. The closing rate initially ... Full text Link to item Cite

Ligand binding to transiently accessible sites: mechanisms for varying apparent binding rates.

Journal Article J Theor Biol · February 7, 1987 Many biological processes are characterized by models where ligand has continuous access to binding sites. Use-dependent processes such as ion channel blockade appear to represent a class of processes where binding site access is transient and is dependent ... Full text Link to item Cite

Transesophageal electrocardiography and cardiac pacing: discussion

Journal Article Circulation · January 1, 1987 Cite

An upper limit for the electrogenic Na-K pump contribution to maximum diastolic potential in feline cardiac Purkinje fibers in steady state.

Journal Article Can J Physiol Pharmacol · May 1986 We have estimated an upper limit for the electrogenic contribution of the Na-K pump to diastolic transmembrane potential. We simultaneously monitored the maximum diastolic potential and the extracellular space potassium activity during exposure to a very h ... Full text Link to item Cite

Influence of buffers on dV/dt(max) recovery kinetics with lidocaine in myocardium

Journal Article American Journal of Physiology - Heart and Circulatory Physiology · December 1, 1985 Buffers are reported to modify electrical function of heart tissue. Since electrophysiological actions of antiarrhythmic drugs are examined in different buffer systems, we set out to examine the influence of buffers on lidocaine's electrophysiological acti ... Cite

Phasic ion channel blockade. A kinetic model and parameter estimation procedure.

Journal Article Mol Pharmacol · October 1985 For excitable membranes, use and frequency dependence represent a progressive incorporation of drug into gated ion channels with repetitive stimulation. In contrast to receptors where access to ligand is continuous in time, we define guarded receptors, suc ... Link to item Cite

Influence of buffers on dV/dtmax recovery kinetics with lidocaine in myocardium.

Journal Article Am J Physiol · September 1985 Buffers are reported to modify electrical function of heart tissue. Since electrophysiological actions of antiarrhythmic drugs are examined in different buffer systems, we set out to examine the influence of buffers on lidocaine's electrophysiological acti ... Full text Link to item Cite

Lipid solubility modulates pH potentiation of local anesthetic block of Vmax reactivation in guinea pig myocardium.

Journal Article Circ Res · October 1984 Current theories envision recovery from local anesthetic block of sodium channels via slow hydrophilic and fast hydrophobic paths. Extracellular pH reduction which increases cationic/neutral anesthetic form should especially prolong recovery kinetics of hi ... Full text Link to item Cite

Mechanisms of use-dependent block of sodium channels in excitable membranes by local anesthetics.

Journal Article Biophys J · July 1984 Many local anesthetics promote reduction in sodium current during repetitive stimulation of excitable membranes. Use-, frequency-, and voltage-dependent responses describe patterns of peak INa when pulse width, pulse frequency, and pulse amplitude are vari ... Full text Link to item Cite

Unitary sodium channels in isolated cardiac myocytes of rabbit.

Journal Article Circ Res · December 1983 Transmembrane ionic movements are thought to occur through special membrane areas or channels. Until recently, it has not been possible to study the properties of individual ionic channels, directly. We have used the extracellular patch clamp technique to ... Full text Link to item Cite

Patent ductus arteriosus in the elderly.

Journal Article South Med J · November 1983 Full text Link to item Cite

Sinus node dysfunction.

Journal Article Cardiol Clin · May 1983 The syndrome of sinus node dysfunction has become increasingly recognized as a cause of symptoms and morbidity, particularly in the elderly population. This syndrome does not represent a homogeneous disease entity. Increased investigation has shown that ma ... Link to item Cite

Bystander accessory pathway during AV node re-entrant tachycardia.

Journal Article Pacing Clin Electrophysiol · May 1983 Between 1970 and July 1980, wide QRS tachycardia due to re-entry confined to the AV node with bystander involvement of an accessory atrioventricular pathway (AAV) was documented in three of 290 patients with the Wolff-Parkinson-White syndrome studied at Du ... Full text Link to item Cite

The electrophysiologic basis and management of symptomatic recurrent tachycardia in patients with Ebstein's anomaly of the tricuspid valve.

Journal Article Am J Cardiol · April 1, 1982 Twenty-two patients with Ebstein's anomaly were evaluated because of recurrent tachycardia. A total of 30 accessory pathways were present in 21 of the 22 patients. Twenty-six accessory pathways were of the atrioventricular (A-V) type while four were Mahaim ... Full text Link to item Cite

Role of Mahaim fibers in cardiac arrhythmias in man.

Journal Article Circulation · July 1981 Twelve patients with evidence of Mahaim fibers are reported, six with nodoventricular (NV) fibers and six with fasciculoventricular (FV) fibers. All patients with NV fibers had left bundle branch block morphology, and a sustained reentrant tachycardia with ... Full text Link to item Cite

Use of the esophageal lead in the diagnosis of mechanisms of reciprocating supraventricular tachycardia.

Journal Article Pacing Clin Electrophysiol · July 1980 Recent studies have emphasized the role of concealed accessory pathways in reciprocating supraventricular tachycardia. Diagnosis has generally required multicatheter electrophysiologic study. We recorded esophageal electrograms during study in 16 patients ... Full text Link to item Cite

The estimation of sinoatrial conduction time in rabbit heart by the constant atrial pacing technique.

Journal Article Circulation · September 1979 This study compared estimates of sinoatrial conduction time (SACT) obtained by constant atrial pacing (CAP) and premature atrial stimulation (PAS) with measured SACT in isolated rabbit right atrial preparations. Transmembrane potentials and surface electro ... Full text Link to item Cite

Sinus node disease.

Journal Article Herz · February 1979 Sinus node dysfunction may be clinically asymptomatic or may lead to serious arrhythmias and sudden death. Symptomatology relates to the resulting brady- or tachyarrhythmias. Clinical and electrocardiographic assessements fail to identify the cause in many ... Link to item Cite

An analysis of the effects of acetylcholine on conduction and refractoriness in the rabbit sinus node.

Journal Article Circ Res · January 1979 The effects of acetylcholine (ACh) on sinus node automaticity, atrio-sinus conduction, and refractoriness were studied in 41 isolated rabbit right atrial preparations. Average control rate was 126 beats/min, and ACh 5 x 10(-8) M, 5 x 10(-7) M, and 5 x 10(- ... Full text Link to item Cite

Effect of pH and [K+] on procainamide uptake by mammalian myocardium

Journal Article Federation Proceedings · January 1, 1979 Cite

Effects of droperidol on depolarization-induced automaticity, maximum upstroke velocity (Vmax) and the kinetics of recovery of Vmax in guinea-pig ventricular myocardium.

Journal Article J Pharmacol Exp Ther · April 1978 The neuroleptic drug droperidol has been shown to have clinically useful antiarrhythmic activity. Prior reports have resulted in conflicting conclusions regarding actions on ventricular myocardial fibers. The present study was carried out to determine whet ... Link to item Cite

The effects of quinidine and verapamil on electrically induced automaticity in the ventricular myocardium of guinea pig.

Journal Article J Pharmacol Exp Ther · February 1976 The effects of 2 to 10 muM verapamil (1-5 mg/l) and 3.8 to 7.6 muM quinidine (2-4 mg/l) on automaticity in ventricular myocardial fibers were examined. Papillary muscles from guinea pigs were mounted in a sucrose gap chamber and transmembrane potential was ... Link to item Cite