Autonomic influences on atrioventricular conduction in conscious dogs

1983 ◽  
Vol 244 (1) ◽  
pp. H102-H108 ◽  
Author(s):  
J. X. Thomas ◽  
W. C. Randall
Keyword(s):  
Right Atrium ◽  
Sympathetic Nerves ◽  
Atrioventricular Conduction ◽  
Relative Importance ◽  
Cardiac Denervation ◽  
Sympathetic Control ◽  
Parasympathetic Nerves ◽  
Upper Limit ◽  
Cardiac Impulse ◽  
The Right

Autonomic innervation of the atrioventricular (AV) junction modulates conduction of the cardiac impulse, the sympathetic nerves facilitating and parasympathetic nerves impeding conduction. Experiments assessed the relative importance of parasympathetic vs. sympathetic control by pharmacologic blockade with atropine (0.2 mg/kg) or propranolol (1.0 mg/kg) while pacing the right atrium (100-400 beats/min) in normal, conscious resting dogs and in dogs that had undergone chronic, intrapericardial cardiac denervation. Maximum pacing rate with 1:1 atrioventricular conduction was termed Rmax. Control Rmax at rest was 125.69 +/- 9.49 beats/min and was slightly reduced after propranolol to 118.28 +/- 10.98 (P = 0.043). After atropine, Rmax was significantly increased to 344 beats/min. Propranolol and atropine together resulted in an Rmax of 308 beats/min, which was significantly less than after atropine alone. Rmax in cardiac-denervated dogs was 301 beats/min, which was not significantly different from that following total pharmacologic blockade. In conscious, resting, unsedated dogs, the upper limit of AV nodal conduction is associated with the level of parasympathetic rather than sympathetic tone; during exercise the sympathetics assume greater importance.

Synergistic nonuniform shortening of atrial refractory period induced by autonomic stimulation

1991 ◽  
Vol 261 (6) ◽  
pp. H1988-H1993 ◽  
Author(s):  
M. Takei ◽  
Y. Furukawa ◽  
M. Narita ◽  
L. M. Ren ◽  
Y. Karasawa ◽  
...  
Keyword(s):  
Right Atrium ◽  
Refractory Period ◽  
Neural Control ◽  
Sympathetic Nerves ◽  
Autonomic Nerve ◽  
Parasympathetic Nerves ◽  
Nodal Region ◽  
The Individual ◽  
The Right ◽  
Stimulation Of

We investigated the nonuniform effects of autonomic nerve stimulation of the effective refractory period (ERP) of the right atrium in the anesthetized dog. Stimulation of the discrete intracardiac sympathetic nerves to the sinoatrial (SA) nodal region uniformly shortened ERPs at three sites in the right atrium after administration of atropine. Right ansa subclavia (RS) stimulation similarly shortened ERPs in the absence of atropine. Stimulation of the discrete intracardiac parasympathetic nerves to the SA nodal region (SAP stimulation) shortened ERPs of the right atrium in a nonuniform manner. Simultaneous RS and SAP stimulation additively shortened ERPs at each site and decreased sinus rate much more than SAP stimulation alone. Shortening of ERP induced by SAP stimulation was greater than that induced by RS stimulation at similar absolute changes in heart rate. These results suggest that simultaneous activation of sympathetic and parasympathetic nerves nonuniformly shortens the ERP in the right atrium as the algebraic sum of the individual responses to each stimulation. However, parasympathetics exert the principal neural control over atrial ERP.

Effects of pituitary adenylate cyclase-activating polypeptide on canine atrial electrophysiology

2001 ◽  
Vol 281 (4) ◽  
pp. H1667-H1674 ◽  
Author(s):  
Masamichi Hirose ◽  
Zeng Leatmanoratn ◽  
Kenneth R. Laurita ◽  
Mark D. Carlson
Keyword(s):  
Adenylate Cyclase ◽  
Left Atrium ◽  
Conduction Velocity ◽  
Right Atrium ◽  
High Intensity ◽  
Cycle Length ◽  
Vagal Stimulation ◽  
Parasympathetic Nerves ◽  
Pituitary Adenylate Cyclase ◽  
The Right

We hypothesized that pituitary adenylate cyclase-activating polypeptide (PACAP) activates intracardiac postganglionic parasympathetic nerves and has a different effect than cervical vagal stimulation. We measured effective refractory period (ERP) and conduction velocity at four atrial sites [high right atrium (HRA), low right atrium (LRA), high left atrium (HLA), and low left atrium (LLA)] and minimum atrial fibrillation (AF) cycle length at 12 atrial sites during cervical vagal stimulation and after PACAP in 26 autonomically decentralized, open-chest, anesthetized dogs. PACAP shortened ERP to a similar extent at all four sites (HRA, 58 ± 2.0 ms; LRA, 60 ± 6.3 ms; HLA, 68 ± 11.5 ms; and LLA, 60 ± 8.3 ms). Low- and high-intensity vagal stimulation shortened ERP at the HRA, but not in the other atrial sites (low-intensity stimulation: HRA, 64 ± 4.0 ms; LRA, 126 ± 5.1 ms; HLA, 110 ± 9.5 ms; and LLA, 102 ± 11.5 ms; high-intensity stimulation: HRA, 58 ± 4.2 ms; and HLA, 101 ± 4.0 ms). Conduction velocity was not altered by any intervention. Minimum AF cycle length after PACAP was similar in both atria but was shorter in the right atrium than in the left atrium during vagal stimulation. After atropine administration, no interventions changed ERP. These results suggest that PACAP shortens atrial refractoriness uniformly in both atria through activation of intrinsic cardiac nerves, not all of which are activated by cervical vagal stimulation.

Supersensitivity to l-norepinephrine of the denervated sinoatrial node

1965 ◽  
Vol 208 (2) ◽  
pp. 255-259 ◽  
Author(s):  
David E. Donald ◽  
John T. Shepherd
Keyword(s):  
Vagus Nerve ◽  
Sinoatrial Node ◽  
Sinus Node ◽  
Sympathetic Nerves ◽  
Cardiac Denervation ◽  
Cervical Vagotomy ◽  
Cervical Ganglia ◽  
The Right ◽  
Cardiac Nerves ◽  
Stimulation Of

Following attempted denervation of the heart by the technic of regional neural ablation, dogs with incomplete cardiac denervation were shown to have the same supersensitivity to l-norepinephrine as dogs in which the denervation of the heart was complete. Dogs with chronic bilateral stellate ganglionectomy or those pretreated with reserpine had cardiac acceleration in response to the administration of tyramine or to stimulation of the stellate cardiac nerves, but did not demonstrate supersensitivity to l-norepinephrine. No supersensitivity was seen in dogs with chronic bilateral cervical vagotomy. Excision of the right stellate and caudal cervical ganglia and the immediately adjacent right vagus nerve resulted in supersensitivity to l-norepinephrine. In these animals cardiac acceleration resulted from stimulation of the left stellate cardiac nerves or from the administration of tyramine. The supersensitivity was lost after excision of the sinoatrial node. It is concluded that one can uniquely denervate the sinus node and that dogs so treated will develop supersensitivity to l-norepinephrine despite the presence of functional sympathetic nerves to the rest of the heart.

ANATOMY OF THE ATRIOVENTRICULAR NODE AND ATRIOVENTRICULAR CONDUCTION SYSTEM

2003 ◽  
Vol 13 (12) ◽  
pp. 3665-3674 ◽  
Author(s):  
SIEW YEN HO ◽  
KAREN P. McCARTHY ◽  
ANEEL ANSARI ◽  
PENNY S. THOMAS ◽  
DAMIAN SÁNCHEZ-QUINTANA
Keyword(s):  
Cardiac Arrhythmias ◽  
Right Atrium ◽  
Atrioventricular Node ◽  
Ventricular Myocardium ◽  
Conduction System ◽  
Atrioventricular Conduction ◽  
Laboratory Animals ◽  
Atrial Myocardium ◽  
The Right

The anatomy of the atrioventricular conduction system was first described nearly a hundred years ago. Since then, it has been an occasional subject of controversy mainly through a lack of adherence to the original definitions based on histology. The gross landmarks for locating the atrial component of the conduction system are found in the right atrium. The components and structure of the system in human are comparable to that found in commonly used laboratory animals. The conduction system is composed of specialized myocytes. Its atrial component, the atrioventricular node, is in contact with atrial myocardium. Having penetrated the atrioventricular insulating plane, the major ventricular bundles are encased in fibrous sheaths that separate the specialized myocytes from the ordinary myocardium. Only at the distal ramifications of the bundle branches do the fibrous sheaths disappear, allowing continuity with ventricular myocardium. Being the only muscular pathway connecting atrial with ventricular myocardium, knowledge of its structure can help in developing potential therapies for some forms of cardiac arrhythmias.

WITHDRAWN: Enlargement of the Right Atrium – Diverticulum or Aneurysm?

2002 ◽  
Author(s):  
R KOBZA ◽  
E OECHSLIN ◽  
R PRETRE ◽  
D KURZ ◽  
R JENNI
Keyword(s):  
Right Atrium ◽  
The Right

Closure of Secundum Atrial Septal Defect with Autologous Right Atrial Patch: Case Report

2005 ◽  
Vol 8 (2) ◽  
pp. 96 ◽  
Author(s):  
Osman Tansel Dar�in ◽  
Alper Sami Kunt ◽  
Mehmet Halit Andac
Keyword(s):  
Atrial Septal Defect ◽  
Right Atrium ◽  
Septal Defect ◽  
Complete Recovery ◽  
Interatrial Septum ◽  
Right Atrial ◽  
Atrial Wall ◽  
Residual Shunt ◽  
Asd Closure ◽  
The Right

Background: Although various synthetic materials and pericardium have been used for atrial septal defect (ASD) closure, investigators are continuing to search for an ideal material for this procedure. We report and evaluate a case in which autologous right atrial wall tissue was used for ASD closure. Case: In this case, we closed a secundum ASD of a 22-year-old woman who also had right atrial enlargement due to the defect. After establishing standard bicaval cannulation and total cardiopulmonary bypass, we opened the right atrium with an oblique incision in a superior position to a standard incision. After examining the secundum ASD, we created a flap on the inferior rim of the atrial wall. A stay suture was stitched between the tip of the flap and the superior rim of the defect, and suturing was continued in a clockwise direction thereafter. Considering the size and shape of the defect, we incised the inferior attachment of the flap, and suturing was completed. Remnants of the flap on the inferior rim were resected, and the right atrium was closed in a similar fashion. Results: During an echocardiographic examination, neither a residual shunt nor perigraft thrombosis was seen on the interatrial septum. The patient was discharged with complete recovery. Conclusion: Autologous right atrial patch is an ideal material for ASD closure, especially in patients having a large right atrium. A complete coaptation was achieved because of the muscular nature of the right atrial tissue and its thickness, which is a closer match to the atrial septum than other materials.

Right Coronary Artery Fistula Draining into the Right Atrium and Associated with Mitral Valve Stenosis: A Case Report

2007 ◽  
Vol 10 (4) ◽  
pp. E325-E328 ◽  
Author(s):  
Ali Gürbüz ◽  
Ufuk Yetkin ◽  
Ömer Tetik ◽  
Mert Kestelli ◽  
Murat Yesil
Keyword(s):  
Case Report ◽  
Coronary Artery ◽  
Mitral Valve ◽  
Right Coronary Artery ◽  
Right Atrium ◽  
Coronary Artery Fistula ◽  
Mitral Valve Stenosis ◽  
The Right

Early Predictive Biochemical, Electrocardiographic and Echocardiographic Markers for Cardiac Damage in Patients with Pulmonic Silicosis

2019 ◽  
Vol 70 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Venera Cristina Dinescu ◽  
Ileana Puiu ◽  
Sorin Nicolae Dinescu ◽  
Diana Rodica Tudorascu ◽  
Elena Catalina Bica ◽  
...  
Keyword(s):  
Heart Disease ◽  
Right Ventricle ◽  
Control Group ◽  
Cardiac Damage ◽  
Right Heart ◽  
Pulmonary Heart Disease ◽  
Upper Limit ◽  
Echocardiographic Parameters ◽  
The Right ◽  
Chronic Pulmonary Heart Disease

The aim of this study was to identify correlations between electrocardiographic and echocardiographic changes in patients with silicosis prior to the occurrence of chronic pulmonary heart disease. We conducted a prospective, descriptive, analytical study, in which we included a group of 67 patients consecutively admitted to the Health Promotion and Occupational Medicine Clinic between December 2016 and January 2018, aged 47 to 78 years.There was a biochemical and electrocardiographic evaluation for each patient as well as a right ventricle echocardiographic evaluation (diameters, volumes, function). A control group, including 25 patients with benign minor diseases that required a cardiologist consultation, was also used. From the electrocardiographic point of view, slight changes were observed regarding the waves of electrical activity of the right ventricle. Taking into account the degree of ventilatory dysfunction (depending on FEV1), changes in right heart echocardiographic parameters were identified. Thus, in what the most important right ventricular parameters, including the tricuspid annular plane systolic excursion (TAPSE) or the RV index of myocardial performance (RVMPI) were concerned, values at the upper limit of normality were recorded in most patients with moderate and severe ventilatory dysfunction. Values of echocardiographic parameters of the right heart at the upper limit of normality, correlated with the degree of ventilatory dysfunction, are early markers for cardiovascular damage in patients with pulmonary silicosis prior to the occurrence of chronic pulmonary heart disease also known ascor pulmonale.

Safe Use of the Assimilative Capacity of the Marine Environment for Waste Disposal – Is It Feasible?

1986 ◽  
Vol 18 (4-5) ◽  
pp. 233-244 ◽  
Author(s):  
J. E. Portmann ◽  
R. Lloyd
Keyword(s):  
Marine Environment ◽  
Salt Marshes ◽  
Safety Margin ◽  
Assimilative Capacity ◽  
Anthropogenic Inputs ◽  
Upper Limit ◽  
Safe Limits ◽  
Control Authority ◽  
The Right ◽  
To Receive

For centuries the sea has absorbed a variety of inputs from rivers, streams, salt marshes and the atmosphere. It is generally accepted that additional limited inputs by man are unlikely to have a significant effect on the marine environment. Various control systems have been constructed to provide a framework within which the regulation of anthropogenic inputs can be achieved. These are briefly reviewed. With care, and in the light of past experience in both freshwater and marine environments, reasonable assumptions or estimations can be applied where uncertainties exist; safe limits can therefore be set for discharges. Case histories are used to illustrate the contention that it is possible to assess the assimilative capacity of a marine area to receive wastes. There is a major distinction to be drawn between contamination and pollution of the marine environment. Moreover, acknowledgement of the assimilative capacity concept in the marine environment does not automatically provide dischargers with the right to utilise that capacity either in part or to the upper limit. What it does is indicate the upper limit which must not be exceeded if pollution is to be avoided, and provide an indication to the control authority of the safety margin involved in the discharge limits they set accordingly.

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