Cardiac responses to electrical stimulation of discrete loci in canine atrial and ventricular ganglionated plexi

1990 ◽  
Vol 259 (5) ◽  
pp. H1365-H1373 ◽  
Author(s):  
C. K. Butler ◽  
F. M. Smith ◽  
R. Cardinal ◽  
D. A. Murphy ◽  
D. A. Hopkins ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Right Ventricular ◽  
Left Atrial ◽  
Right Atrial ◽  
Intramyocardial Pressure ◽  
Cardiac Responses ◽  
Ganglionated Plexi ◽  
The Right ◽  
Ganglionated Plexus ◽  
Stimulation Of

The purpose of the present study was to examine cardiac effects induced by electrical stimulation (1-4 V, 1 ms, 200 Hz) of discrete loci within the ganglionated plexi located on canine atria and ventricles. When 20 loci in the right atrial ventral ganglionated plexi of 11 anesthetized open-chest dogs were stimulated, bradycardia and/or right and left atrial force suppression occurred when, on average, 15% of these loci were stimulated. Bradycardia and atrial force suppression were elicited when, on average, 8% of 15 loci in the left atrial ventral ganglionated plexi of eight dogs was stimulated. When these loci were restimulated after acute decentralization, cardiac responses were attenuated or occasionally eliminated. After atropine (1 mg/kg iv) administration, repeat stimulation of loci in the right but not left atrial ganglionated plexus induced tachycardia. Stimulation of loci in the right ventricular ganglionated plexus after the subsequent administration of desipramine (1 mg/kg iv) in six dogs resulted in an increase in right ventricular conus intramyocardial pressure. After hexamethonium administration (10 mg/kg iv, followed by a continuous infusion of 1 mg.kg-1.min-1), sympathetic responses were no longer elicited from one of the five dogs in which loci in the right atrial ganglionated plexi and from two of the six dogs in which loci of the right ventricular ganglionated plexus had elicited responses. We conclude that atrial and ventricular ganglionated plexi contain efferent parasympathetic, efferent sympathetic, and afferent neurons.

"Summation" of the increase in heart rate from stimulation of atrial receptors

1980 ◽  
Vol 58 (6) ◽  
pp. 666-672
Author(s):  
P. V. Greenwood ◽  
C. T. Kappagoda
Keyword(s):  
Heart Rate ◽  
Left Atrial ◽  
Superior Vena ◽  
Right Atrial ◽  
Propranolol Hydrochloride ◽  
Superior Vena Caval ◽  
The Right ◽  
Atrial Receptors ◽  
Stimulation Of ◽  
Wire Cage

In dogs anaesthetized with chloralose, application of stimuli which are likely to activate left atrial (L.A.) and right atrial (R.A.) receptors (complex unencapsulated endings) has been shown to result in an increase in heart rate. The present investigation was undertaken to determine whether the response elicited by the application of one stimulus (i.e., to the left atrium) could be enhanced by the application of a second stimulus (i.e., to the right atrium) in the same animal.The L.A. receptors were stimulated by distending a small balloon at the right upper pulmonary vein-L.A. junction and the R.A. receptors by "expanding" a spherical wire cage positioned at the superior vena caval (S.V.C.)-R.A. junction. Pressures in the S.V.C., R.A., L.A., and femoral artery were measured and the electrocardiogram monitored.In eight dogs stimulation of L.A. receptors resulted in an increase in heart rate (H.R.) of 18.5 beats/min (SEM 6.0; N = 23). In the same animals stimulation of R.A. receptors resulted in an increase in H.R. of 14.6 beats/min (SEM 2.0; N = 25). Application of both stimuli simultaneously resulted in an increase of 32.2 beats/min (SEM 8.0; N = 13). In four dogs propranolol hydrochloride (0.5 mg/kg) markedly diminished the response. In three dogs the response was abolished by bretylium tosylate (10 mg/kg).It is concluded that the increase in H.R. resulting from the application of these two stimuli could be "summated" and these findings support the proposition that the receptors in the two atria act as a functional entity.

INFLUENCE OF RIGHT VENTRICULAR LEAD IMPLANTATION SITE CHOICE ON PACING EFFICIENCY

2020 ◽  
pp. 13-17
Author(s):  
Dmitrii Aleksandrovich Lopyn ◽  
Stanislav Valerevich Rybchynskyi ◽  
Dmitrii Evgenevich Volkov
Keyword(s):  
Heart Failure ◽  
Right Ventricular ◽  
Longitudinal Strain ◽  
Treatment Options ◽  
Global Longitudinal Strain ◽  
Optimal Method ◽  
Cardiac Stimulation ◽  
Ventricular Lead ◽  
The Right ◽  
Stimulation Of

Currently the electrophysiological treatment options have been considered to be the most effective for many patients with arrhythmogenic cardiomyopathies, as well as in those with arrhythmias on the background of heart failure. Currently, the dependence of efficiency of the pacemakers on the location of the electrodes has been proven. In order to study the effect of a myocardial dysynchrony on the effectiveness of pacing depending on the location of the right ventricular electrode, an investigation has been performed. This study comprised the patients with a complete atrioventricular block, preserved ejection fraction of the left ventricle (more than 50 %), with no history of myocardial infarction, who were implanted with the two−chamber pacemaker. It has been established that the best results were achieved with a stimulation of the middle and lower septal zone of the right ventricle, the worst ones were obtained with a stimulation of its apex. It has been found that the dynamics of the magnitude of segmental strains and a global longitudinal strain coincided with the dynamics of other parameters of the pacemaker effectiveness, which indicated the pathogenetic value of myocardial dysynchrony in the progression of heart failure after implantation of the pacemaker. Therefore it could be concluded that the studying of myocardial mobility by determining a longitudinal strain for assessing the functional state of the myocardium and the effectiveness of pacing is highly advisable. It is emphasized that the use of the latest strains−dependent techniques for cardiac performance evaluation in the patients with bradyarrhythmia have a great potential to predict the development of chronic heart failure and to choose the optimal method of physiological stimulation of the heart. Key words: right ventricular lead, cardiac stimulation, myocardial dyssynchrony.

Cobra head deformity of atrial septal occluder: blessing in disguise

2020 ◽  
pp. 1-2
Author(s):  
Uma Devi Karuru ◽  
Saurabh Kumar Gupta
Keyword(s):  
Atrial Septal Defect ◽  
Left Atrial ◽  
Septal Defect ◽  
Atrial Septum ◽  
Right Atrial ◽  
Septal Occluder Device ◽  
Occluder Device ◽  
The Right

Abstract It is not uncommon to have prolapse of the atrial septal occluder device despite accurate measurement of atrial septal defect and an appropriately chosen device. This is particularly a problem in cases with large atrial septal defect with absent aortic rim. Various techniques have been described for successful implantation of atrial septal occluder in such a scenario. The essence of all these techniques is to prevent prolapse of the left atrial disc through the defect while the right atrial disc is being deployed. In this brief report, we illustrate the use of cobra head deformity of the device to successfully deploy the device across the atrial septum.

Control of atrial natriuretic factor by right and left atrial distension in pregnant sheep

1995 ◽  
Vol 268 (6) ◽  
pp. R1411-R1417
Author(s):  
D. Javeshghani ◽  
S. Mukaddam-Daher ◽  
L. Fan ◽  
Z. Guan ◽  
J. Gutkowska ◽  
...  
Keyword(s):  
Atrial Natriuretic Factor ◽  
Left Atrial ◽  
Atrial Pressure ◽  
Right Atrial ◽  
Natriuretic Factor ◽  
Pregnant Sheep ◽  
Vascular Catheters ◽  
The Right ◽  
Left Atrial Distension ◽  
Atrial Natriuretic

Previous studies of the atrial stretch-atrial natriuretic factor (ANF) relationship during pregnancy have employed volume expansion and measured only right atrial pressure (RAP). Consequently, we studied nonpregnant (n = 7) and 115- to 125-day pregnant (n = 7) sheep and assessed the ANF response to changes of RAP and left atrial pressure (LAP) induced by graded balloon inflation. Ewes prepared with vascular catheters and atrial balloons were studied after recovery from preparatory surgical procedures. The basal levels of mean arterial pressure (MAP, 83 +/- 3 mmHg), RAP (2.1 +/- 0.7 mmHg), LAP (4.7 +/- 0.9 mmHg), and heart rate (HR, 102 +/- 6 beats/min) were similar in nonpregnant and pregnant sheep. Pregnancy also resulted in elevation of ANF concentration from 25 +/- 6 to 57 +/- 4 fmol/ml. With right atrial distension, the RAP-ANF relationships were similar in both nonpregnant and pregnant sheep, with a 10-mmHg increase in RAP increasing ANF by an average of 95 +/- 9 fmol/ml. In nonpregnant sheep, the LAP-ANF relationship was more responsive than RAP-ANF because a 10-mmHg increase in LAP resulted in a 193 +/- 10 fmol/ml increase in ANF. Moreover, during pregnancy, the LAP-ANF relationship was significantly more sensitive because a 10-mmHg increase in LAP resulted in a 433 +/- 15 fmol/ml elevation of ANF. These data demonstrate that plasma ANF levels are more responsive to distension of the left atria than to the right. More importantly, the ANF response to left, but not right, atrial distension is enhanced by pregnancy.

Fastigial nucleus-mediated respiratory responses depend on the medullary gigantocellular nucleus

2001 ◽  
Vol 91 (4) ◽  
pp. 1713-1722 ◽  
Author(s):  
Fadi Xu ◽  
Tongrong Zhou ◽  
Tonya Gibson ◽  
Donald T. Frazier
Keyword(s):  
Electrical Stimulation ◽  
Ibotenic Acid ◽  
Major Effect ◽  
Fastigial Nucleus ◽  
Respiratory Response ◽  
The Right ◽  
Spontaneously Breathing ◽  
Respiratory Responses ◽  
Gigantocellular Nucleus ◽  
Stimulation Of

Electrical stimulation of the rostral fastigial nucleus (FNr) alters respiration via activation of local neurons. We hypothesized that this FNr-mediated respiratory response was dependent on the integrity of the nucleus gigantocellularis of the medulla (NGC). Electrical stimulation of the FNr in 15 anesthetized and tracheotomized spontaneously breathing rats significantly altered ventilation by 35.2 ± 11.0% ( P < 0.01) with the major effect being excitatory (78%). This respiratory response did not significantly differ from control after lesions of the NGC via bilateral microinjection of kainic or ibotenic acid (4.5 ± 1.9%; P > 0.05) but persisted in sham controls. Eight other rats, in which horseradish peroxidase (HRP) solution was previously microinjected into the left NGC, served as nonstimulation controls or were exposed to either 15-min repeated electrical stimulation of the right FNr or hypercapnia for 90 min. Histochemical and immunocytochemical data showed that the right FNr contained clustered HRP-labeled neurons, most of which were double labeled with c-Fos immunoreactivity in both electrically and CO2-stimulated rats. We conclude that the NGC receives monosynaptic FNr inputs and is required for fully expressing FNr-mediated respiratory responses.

Rebound cardiovascular responses following stimulation of canine vagosympathetic complexes or cardiopulmonary nerves

1985 ◽  
Vol 63 (9) ◽  
pp. 1122-1132 ◽  
Author(s):  
J. A. Armour ◽  
W. C. Randall
Keyword(s):  
Electrical Stimulation ◽  
Arterial Pressure ◽  
Cardiovascular System ◽  
Cardiovascular Responses ◽  
Systemic Arterial Pressure ◽  
Cardiac Responses ◽  
Stimulation Of

Electrical stimulation of a canine vagosympathetic complex or a cardiopulmonary nerve can elicit a variety of negative chronotropic and inotropic cardiac responses, with or without alterations in systemic arterial pressure. In the period immediately following cessation of such a stimulation "rebound" tachycardia, increased inotropism above control values in one or more regions of the heart, and (or) elevation in systemic arterial pressure can occur. These "rebound" phenomena are abolished by propranolol or ipsilateral chronic sympathectomy. It is proposed that "vagal" poststimulation "rebound" of the canine cardiovascular system is primarily the result of activation of sympathetic neural elements present in the vagosympathetic complexes or cardiopulmonary nerves.

scholarly journals Tricuspid Valve Dysplasia in a Dog

2019 ◽  
Vol 47 ◽  
Author(s):  
Gabriela De Carvalho Cid ◽  
Luciano Da Silva Alonso ◽  
Ana Paula De Castro Pires ◽  
Mariana Siqueira d'Avila Taïna Gonçalves ◽  
Taïna Gonçalves ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Tricuspid Valve ◽  
Right Atrial ◽  
Pulmonary Insufficiency ◽  
Papillary Muscles ◽  
Ventricular Enlargement ◽  
Pathological Findings ◽  
Chordae Tendineae ◽  
Clinicopathological Findings ◽  
The Right

Background: Congenital cardiac diseases are a common cause of death in puppies. Tricuspid valve dysplasia is characterized by thickening and displacement of the leaflets of the tricuspid valve, agenesis of the valves, and incomplete separation of valve components. Papillary muscles may fuse and display shortened or absent chordae tendineae that contribute to tricuspid regurgitation. Diagnostic features of tricuspid valve dysplasia include cardiomegaly with massive right atrium enlargement on thoracic radiography and tricuspid insufficiency on an ultrasound. We aimed to describe clinicopathological findings in a dog (Canis familiaris) with tricuspid dysplasia.Case: We aimed to describe tricuspid valve dysplasia in a dog referred for necropsy at the Anatomical Pathology Sector of The Rural Federal University of Rio de Janeiro, Brazil, with a clinical history of abdominal swelling, dyspnea, cyanosis, ascites, and prostration. Echocardiography and abdominal ultrasound revealed right ventricular enlargement, hepatomegaly, and splenomegaly. Examination of the heart showed prominent enlargement, thickening and dilation of the right chambers, thickening of the tricuspid leaflets, and moderately shortened chordae tendineae. The liver was enlarged, with a nutmeg pattern, and foci of clotting and fibrin adhesions in the lateral right lobule.Discussion: Epidemiological, clinical, and pathological findings were consistent with tricuspid valve dysplasia. Although structural abnormalities of the tricuspid and mitral valves are well known in fetuses and neonates, congenital and secondary tricuspid malformations are rare in dogs. The survival rate is associated with the severity of heart lesions. Tricuspid valve dysplasia is mostly observed in large-breed dogs (>20 kg), particularly in Labrador Retrievers, Boxers, and German Shepherds. Regardless, most dogs with tricuspid valve dysplasia are of a pure-breed, which differs from our findings because our dog was a mongrel. Our dog displayed signs of dyspnea, cyanosis, abdominal swelling, prostration, and enlarged liver and spleen on ultrasound examination. Tricuspid valve dysplasia led to heart enlargement and right congestive heart failure, with consequent ascites, abdominal swelling, weakness, lethargy, jugular venous distension, and hepatomegaly. Overall, the heart showed prominent enlargement, thickening and dilation of the right chambers, thickening of the tricuspid leaflets, and moderately shortened chordae tendineae. The liver had a nutmeg pattern. Tricuspid valve dysplasia is characterized by malformation of the tricuspid valve leaflets, chord tendineae, or papillary muscles. Malformed tricuspid valves are known to result in variable degrees of regurgitation, leading to right atrial overflow and ventricular eccentric hypertrophy. Differential diagnosis includes myocarditis, tricuspid valve endocarditis, tricuspid endocardiosis, tricuspid valve prolapse and right ventricular dysplasia, right ventricular enlargement with tricuspidal regurgitation due to pulmonary insufficiency, and arrhythmogenic right ventricular cardiomyopathy. Signs of heart murmurs (irregular sounds of the heart) on clinical examination may indicate an irregular blood flow pattern, and imaging tests may be necessary for assessing the presence and severity of any lesions. The epidemiologic, clinical, and pathological findings were consistent with those of tricuspid valve dysplasia. 

scholarly journals Effect of Low-Level Electrical Stimulation of the Arotic Root Ventricular Ganglionated Plexi on Electrical and Structural Remodling in Dogs with Heart Failure

2016 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Heart Failure ◽  
Nervous System ◽  
Electrical Stimulation ◽  
Autonomic Nervous System ◽  
Aortic Root ◽  
General Argument ◽  
Low Level ◽  
Ganglionated Plexi ◽  
Atrial Enlargement ◽  
Stimulation Of

Low-level electrical stimulation (LL-ES) of aortic root ventricular ganglionated plexi (GP) was proved to be antiarrhythmic in the initiation of AF mediated by autonomic nervous system. However,it is still uncertain whether LL-ES of the ventricular GP can reverse the structural remodeling of myocardial fibrosis and atrial enlargement following heart failure by attenuating the sympathetic tone. Therefore,this review will give an general argument on this topic.

scholarly journals Sensory and motor electrophysiological mapping of the cerebellum in humans

2020 ◽  
Author(s):  
Reiko Ashida ◽  
Peter Walsh ◽  
Jonathan C.W. Brooks ◽  
Richard J. Edwards ◽  
Nadia L. Cerminara ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Evoked Potentials ◽  
Posterior Fossa ◽  
Posterior Lobe ◽  
Posterior Fossa Surgery ◽  
Motor Mapping ◽  
Human Cerebellum ◽  
Limb Muscles ◽  
The Right ◽  
Stimulation Of

AbstractDamage to the cerebellum during posterior fossa surgery can lead to ataxia and in paediatric cases, the risk of cerebellar mutism syndrome. Animal electrophysiological and human imaging studies have shown compartmentalisation of sensorimotor and cognitive functions within the cerebellum. In the present study, electrophysiological monitoring of sensory and motor pathways was carried out to assess the location of limb sensorimotor representation within the human cerebellum, as a potential approach for real time assessment of neurophysiological integrity to reduce the incidence of cerebellar surgical morbidities.Thirteen adult and paediatric patients undergoing posterior fossa surgery were recruited. For sensory mapping (n=8), electrical stimulation was applied to the median nerves, the posterior tibial nerves, or proximal and distal limb muscles and evoked field potential responses were sought on the cerebellar surface. For motor mapping (n=5), electrical stimulation was applied to the surface of the cerebellum and evoked EMG responses were sought in facial and limb muscles.Evoked potentials on the cerebellar surface were found in two patients (25% of cases). In one patient, the evoked response was located on the surface of the right inferior posterior cerebellum in response to stimulation of the right leg. In the second patient, stimulation of the extensor digitorum muscle in the left forearm evoked a response on the surface of the left inferior posterior lobe. In the motor mapping cases no evoked EMG responses could be found.Intraoperative electrophysiological mapping, therefore, indicates it is possible to record evoked potentials on the surface of the human cerebellum in response to peripheral stimulation.

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