scholarly journals Sinoatrial node pacemaker cell pool dynamics upon synchronization with vagus nerve rhythm

2019 ◽  
Vol 6 (3) ◽  
pp. 114-116
Author(s):  
krovskii VM ◽  
Nechepurenko AA ◽  
 Tarasov DG ◽  
Korotkov KG ◽  
Abushkevich VG
Keyword(s):  
Vagus Nerve ◽  
High Frequency ◽  
Sinoatrial Node ◽  
Vena Cava ◽  
Video Camera ◽  
Pacemaker Cell ◽  
Cell Dynamics ◽  
Cardiac Synchronization ◽  
Excitation Processes ◽  
Electrical Impulses

Aim: To reveal the dynamics of sinoatrial node pacemaker cell pools upon synchronization with vagus nerve rhythm through the model of vagal-cardiac synchronization. Materials and methods: Observations were carried out on 10 narcotized cats. The animals were tracheostomized and pump-ventilated, and the pericardium accessed via an open-chest transsternal incision. A device (KELSY scanner manufactured by Elsys, St. Petersburg, Russia) accompanied by a microscope and a video-camera, to visualize the luminescence of excitation processes in the sinoatrial node in a high-frequency electromagnetic field (1024 Hz) was placed in the sinoatrial area of a working heart. Luminescent focus in the sinoatrial node was registered as a peripherally cut end of the vagus nerve was stimulated with bursts of electrical impulses (5 impulses, 2 ms, 20 Hz) from an electrostimulator. Results: Luminescence localized at the entrance of the cranial vena cava was visualized in a high-frequency electrical field in narcotized cats. The luminescent focal area was not homogenous and looked like a number of luminescent pools. Upon vagal-cardiac synchronization caused by the stimulation of a peripherally cut end of the vagus nerve with bursts of electrical impulses, the focus was wide and solid. Conclusion: Here, pacemaker cell dynamics were studied in the feline heart. When vagal- cardiac synchronization was activated, synchronization of the heart with vagus nerve rhythm was accompanied by an increase in the early depolarization area in the sinoatrial area of the feline heart. The mechanisms underlying heart rate synchronization are not clearly defined. Rhythm is achieved through actions of the SA node and the vagus nerve. Our data confirm the vagal- cardiac synchronization model.

scholarly journals The method of determining the number of excited efferent cardiac fibers in the vagus nerve of a cat

2019 ◽  
Vol 6 (5) ◽  
pp. 228-230
Author(s):  
Minenko IA ◽  
Pokrovsky VM ◽  
Tarasov DG ◽  
Nechepurenko AA ◽  
Pokhotko AG ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Vagus Nerve ◽  
High Frequency ◽  
Thyroid Cartilage ◽  
Glass Tube ◽  
Heart Rhythm ◽  
Video Camera ◽  
Cervical Region ◽  
High Frequency Electromagnetic Field ◽  
Cardiac Fibers

Objective: Developing method of determination the number of excited efferent cardiac fibers in the cervical region of the vagus nerve of a cat by estimating the area of the glow in the high-frequency electromagnetic field inside the nerve. Materials and methods: The observations were carried out on cats in conditions of superficial (27 cats) or deep anesthesia (13 cats out of 27) and irritation of the vagus nerve with electrical impulses (14 cats out of 27). The right vagus nerve on cat’s neck was allocated and cut at the level of the lower edge of thyroid cartilage. The central end was inserted into a glass tube. Before the cut end in the transverse plane, a scanner from the unit, which creates a high-frequency electromagnetic field was installed. The glow from the scanner were recorded by a video camera through the microscope. At the same time, the ECG was recorded. Based on the ECG signal, for the processing we took the centers of glow related to the heart rhythm. The results were processed in the "STATISTIKA 6.0" program. Results: In superficial anesthesia, the number of excitable efferent fibers was 350 or 70.0% of the available ones. In case of deep anesthesia, 193 or 38.6% accordingly. In case of nerve stimulation above the transection site all available efferent fibers have been excitable. Conclusions: Results of this work suggest a way to identify and determine the number of excitable efferent cardiac fibers in the vagus nerve and their localization on the cross section of the central end of the nerve from the area of luminescence in high-frequency electric field.

scholarly journals Assembly of the Cardiac Pacemaking Complex: Electrogenic Principles of Sinoatrial Node Morphogenesis

2021 ◽  
Vol 8 (4) ◽  
pp. 40
Author(s):  
Marietta Easterling ◽  
Simone Rossi ◽  
Anthony J Mazzella ◽  
Michael Bressan
Keyword(s):  
Cardiac Tissue ◽  
Sinoatrial Node ◽  
Cardiac Pacemaker ◽  
Tissue Level ◽  
Rhythmic Contraction ◽  
Entire Volume ◽  
Impulse Generation ◽  
Cardiac Pacemaking ◽  
Electrical Impulses ◽  
Sufficient Strength

Cardiac pacemaker cells located in the sinoatrial node initiate the electrical impulses that drive rhythmic contraction of the heart. The sinoatrial node accounts for only a small proportion of the total mass of the heart yet must produce a stimulus of sufficient strength to stimulate the entire volume of downstream cardiac tissue. This requires balancing a delicate set of electrical interactions both within the sinoatrial node and with the downstream working myocardium. Understanding the fundamental features of these interactions is critical for defining vulnerabilities that arise in human arrhythmic disease and may provide insight towards the design and implementation of the next generation of potential cellular-based cardiac therapeutics. Here, we discuss physiological conditions that influence electrical impulse generation and propagation in the sinoatrial node and describe developmental events that construct the tissue-level architecture that appears necessary for sinoatrial node function.

Atrial ectopic foci in the canine heart: hierarchy of pacemaker automaticity

1980 ◽  
Vol 238 (6) ◽  
pp. H788-H793 ◽  
Author(s):  
S. B. Jones ◽  
D. E. Euler ◽  
W. C. Randall ◽  
G. Brynjolfsson ◽  
E. L. Hardie
Keyword(s):  
Inferior Vena ◽  
Sinoatrial Node ◽  
Vena Cava ◽  
Intrinsic Rate ◽  
Canine Heart ◽  
Average Heart Rate ◽  
Vena Cava Inferior ◽  
Cardiac Pacemakers ◽  
Junctional Rhythm ◽  
Adjacent Tissue

The sinoatrial node (SAN) and adjacent tissue of the sulcus terminalis were surgically excised in sequential multiple sections to study the location and intrinsic rate of emerging pacemakers in the acute open-chest dog. Under chloralose anesthesia total of 17 ectopic atrial pacemakers emerged in 12 dogs ranging in location from the anterior interatrial band, midsulcus terminalis, and junction of the inferior vena cava-inferior right atrium. Four AV junctional and one idioventricular pacemakers also emerged in these experiments. Each successively inferior focus had a slower rate than the SAN. The average heart rate of the atrial ectopic pacemakers was 73 +/- 4% of the SAN but that the AV junctional pacemakers was 56 +/- 4% of the SAN (P less than 0.05). The greatest reductions in rate were achieved with total excision of the SAN and entire sulcus terminalis, but in only 50% of the animals did this result in a junctional rhythm. The location and rate of atrial ectopic foci support the notion that the AV junctional region is not the fastest pacemaker in the absence of the classically defined SAN and suggest that atrial ectopic pacemakers are intermediate in the hierarchy of cardiac pacemakers in the dog.

High frequency irreversible electroporation (H-FIRE) as a novel method of targeted cell death.

2016 ◽  
Vol 34 (4_suppl) ◽  
pp. 277-277
Author(s):  
Imran A Siddiqui ◽  
Russell C. Kirks ◽  
Erin H Baker ◽  
Eduardo Latouche ◽  
Matt Dewitt ◽  
...  
Keyword(s):  
Cell Death ◽  
High Frequency ◽  
Irreversible Electroporation ◽  
Vital Signs ◽  
Cardiac Monitoring ◽  
Vascular Integrity ◽  
Cancer Cell Death ◽  
Novel Method ◽  
Vascular Structures ◽  
Cardiac Synchronization

277 Background: Irreversible electroporation unlike ablation is excellent in inducing cell death via apoptosis. It, however, has disadvantages of electrical conduction via cardiac and nervous tissue. This results in requiring cardiac monitoring and general anesthesia and paralytics while performing electroporation. We hypothesized a novel high-frequency IRE (H-FIRE) system employing ultra-short bipolar pulses would obviate the need for cardiac synchronization and paralytics while maintaining measurable effect on cell death. Methods: Female swine (55-65Kg) were used. Two H-FIRE electrodes were inserted into the liver (1.5-cm spacing). In the absence of paralytics H-FIRE pulses were delivered (2250V, 2-5-2 pulse configuration) at different on times (100 vs. 200μs) or number of pulses (100 vs. 300). Next electrodes were placed across major hepatic vascular structures and H-FIRE performed. At conclusion tissue was resected and analyzed histologically. Results: 24 H-FIREs were performed (mean ablation time 275 secs). No EKG abnormalities or changes in vital signs were measured during H-FIRE procedures. In 1/24 H-FIREs minor twitching of the rectus abdominis was recorded coinciding with pulse delivery. Histologically, tissues had effective electroporation as evidenced by cell death and caspase activity. Blinded scoring was performed for necrosis and apoptosis. Areas of cell death were predictable. No significant vascular damage or coagulated/thermally-desiccated blood was detected within major vessels following H-FIRE. Conclusions: H-FIRE is a novel way of liver electroporation. It produces predictable cell apoptosis without the requirement of paralytics and alteration of electrocardiographic signals as compared to traditional electroporation, while preserving underlying vascular integrity. Its application in cancer cell death needs to be further studied, but it has a potential for clinical use in targeting tumors with minimal morbidity and associated cardiac and neurologic side effects.

scholarly journals The Warden Procedure through a Posterolateral Thoracotomy Approach

2014 ◽  
Vol 41 (5) ◽  
pp. 499-501 ◽  
Author(s):  
Sowmya Ramanan ◽  
Navaneetha Sasikumar ◽  
Soman Rema Krishna Manohar ◽  
Kotturathu Mammen Cherian
Keyword(s):  
Superior Vena Cava ◽  
Septal Defect ◽  
Sinoatrial Node ◽  
Superior Vena ◽  
Vena Cava ◽  
Posterolateral Thoracotomy ◽  
Venous Obstruction ◽  
Venae Cavae ◽  
Anomalous Pulmonary Venous Connection ◽  
Sinoatrial Node Dysfunction

The Warden procedure for the correction of a right-sided partial anomalous pulmonary venous connection to the high superior vena cava is well established. It has the advantages of avoiding sinoatrial node dysfunction and pulmonary and systemic venous obstruction. In the case related here, a 3-year-old girl presented with a superior vena cava type of sinus venosus atrial septal defect and an anomalously draining right upper pulmonary vein, with bilateral superior venae cavae. Our approach to the Warden procedure was through a right posterolateral thoracotomy, which provided additional advantages.

Effect of Auricular Acupuncture on Gastrointestinal Motility and Its Relationship with Vagal Activity

2013 ◽  
Vol 31 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Han Li ◽  
Yin-Ping Wang
Keyword(s):  
Vagus Nerve ◽  
High Frequency ◽  
Low Frequency ◽  
Autonomic Nerve ◽  
Auricular Acupuncture ◽  
Vagal Activity ◽  
Nerve Function ◽  
Gi Transit ◽  
The Relationship ◽  
Gi Motility

Background Vagus nerve stimulation is capable of regulating autonomic nerve function. In Traditional Chinese Medicine, the effect of auricular acupuncture (AA) is mediated by the vagus. This study was designed to investigate the effect of AA on gastrointestinal (GI) motility and the relationship of this effect with the vagus nerve. Methods 50 rats were divided into five groups for observation of the effects of different types of acupuncture and influencing factors: control, AA, somatic acupuncture (SA), atropine and atropine+AA. The acupuncture points used for AA were ST (Stomach) and SI (Small intestine), while the acupuncture point used for SA was ST36. Electroacupuncture was performed for 15 min. A model of reduced GI motility was established using ethanol, and GI transit rate was used to measure GI motility. Heart rate variability (HRV) and the effect of atropine administration were investigated to study the relationship between AA and vagal activity. Results The GI transit rate increased in both the AA and SA groups compared with control, and no significant difference was found between their effects. In addition, after atropine administration, AA was found to be ineffective in influencing the GI transit rate. In the HRV analysis, no significant differences were found in the absolute low frequency normalised units, high frequency normalised units or the low frequency/high frequency component ratio in the AA or SA groups compared with control. After administration of atropine AA still had no effect on HRV. Conclusions The function of AA in improving GI motility is similar to that of SA, and this effect can be blocked by the presence of atropine, indicating that this effect is regulated by the vagus. However, HRV did not reflect the acupuncture-induced changes in vagal nerve function.

scholarly journals Synchronization of sinoatrial node pacemaker cell clocks and its autonomic modulation impart complexity to heart beating intervals

Heart Rhythm ◽  
2014 ◽  
Vol 11 (7) ◽  
pp. 1210-1219 ◽  
Author(s):  
Yael Yaniv ◽  
Ismayil Ahmet ◽  
Jie Liu ◽  
Alexey E. Lyashkov ◽  
Toni-Rose Guiriba ◽  
...  
Keyword(s):  
Sinoatrial Node ◽  
Autonomic Modulation ◽  
Pacemaker Cell ◽  
Heart Beating
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