The Critical Use of the His Bundle Electrogram

The technique for electrode catheter recording of consistent and stable His bundle activity presently used in the clinical laboratory was initially developed as an investigational tool. In the clinical laboratory, the His bundle electrogram, in conjunction with the surface electrocardiogram--a technique that has been termed His bundle-electrocardiography by Castellano--has provided a more accurate means of localizing the site of conduction abnormality in patients with various forms of heart block. In addition, this technique has been utilized to study various physiological and pharmacological interventions, arrhythmias, and the Wolff-Parkinson-White syndrome

The Gouaux-Ashman Phenomenon: His Bundle Recordings

In conclusion, it is important to state the use of His bundle-electrocardiography in differentiating supraventricular beats with aberration from ventricular beats requires a critical approach to the interpretations of deflections appearing in the P-R segment. The use of quantitative rather than qualitative tests is essential when only the His bundle recording is used as opposed to the simultaneously recorded activity from the proximal bundle branches. In some cases, His bundle pacing may be helpful in reproducing spontaneously occurring aberrant patterns

Mechanisms of Supraventricular Tachycardia

In summary, we have found a close association between the stress of A-V nodal conduction and the occurrence of atrial dispersion or aberration. We could not explain atrial dispersion on the basis of incomplete recovery of atrial activity, slowing of atrial conduction, or the occurrence of atrial fusion. We postulate that the phenomenon of dispersion of atrial activation is related to the functional dissociation within the A-V node seen during situations which stress A-V conduction. This phenomenon may represent a mechanism whereby a second area of turnaround other than the A-V node is involved in reentry atrial tachyarrhythmias. Indeed, such a mechanism could provide a physiological basis for the concept of the atrial bridge being involved in supraventricular tachycardias and reciprocal beating

Human hair follicle biomagnetism: potential biochemical correlates

Background: The S100 protein family is linked to energy transfer in cells of vertebrates at a molecular level. This process involves the electron transfer chain and therefore, as inferred from Faraday’s Law, electron movement will induce electromagnetic fields (EMFs). Biological entities emit photoelectrons that can be tracked and visualized by small paramagnetic nano-sized iron particles. Methods: We have developed an optical microscopic approach for imaging electromagnetic activity of hair follicles utilizing nano-sized iron particles (mean diameter 2000nm) in Prussian Blue Stain solution (PBS Fe 2000). Results: We found that the human hair follicle emits electromagnetic fields (EMFs) based on metabolic activity within the follicle, which is associated with the activity of selective S-100 proteins. Conclusions: Our results link the molecular biochemical energy associated with the S100 family of proteins and biomagnetism of human hair follicles

Slow Conduction through an Arc of Block: A Basis for Arrhythmia Formation Post-Myocardial Infarction

Introduction The electrophysiologic basis for characteristic rate-dependent, constant-late-coupled (390 + 54 milliseconds) premature ventricular beats (PVBs) present 4–5 days following coronary artery occlusion were examined in 108 anesthetized dogs. Methods and results Fractionated/double potentials were observed in injured zone bipolar and composite electrograms at prolonged sinus cycle lengths (1,296 ± 396 milliseconds). At shorter cycle lengths, conduction of the delayed potential decremented, separating from the initial electrogram by a progressively prolonged isoelectric interval. With sufficient delay of the second potential following an isoelectric interval, a PVB was initiated. Both metastable and stable constant-coupled PVBs were associated with Wenckebach-like patterns of delayed activation following an isoelectric interval. Signal-averaging from the infarct border confirmed the presence of an isoelectric interval preceding the PVBs (N = 15). Pacing from the site of double potential formation accurately reproduced the surface ECG morphology (N = 15) of spontaneous PVBs. Closely-spaced epicardial mapping demonstrated delayed activation across an isoelectric interval representing “an arc of conduction block.” Rate-dependent very slow antegrade conduction through a zone of apparent conduction block (N = 8) produced decremental activation delays until the delay was sufficient to excite epicardium distal to the original “arc of conduction block,” resulting in PVB formation. Conclusion The present experiments demonstrate double potential formation and rate-dependent constant-coupled late PVB formation in infarcted dog hearts. Electrode recordings demonstrate a prolonged isoelectric period preceding PVB formation consistent with very slow conduction (<70 mm/s) across a line of apparent conduction block and may represent a new mechanism of PVB formation following myocardial infarction

Преступления в таможенной сфере: характеристика, выявление, ответственность

Объектом исследования является таможенный орган как средство обеспечения экономической безопасности. Цель работы - выявление проблем, возникающих у таможенных органов, как органов дознания при расследовании преступлений в сфере экономической деятельности и разработка рекомендаций, направленных на повышение эффективности правоохранительной деятельности таможенных органов как органов дознания. В процессе исследования был проведен анализ нормативно-правовой базы, регулирующей деятельность таможенных органов, а также практика расследования уголовных дел. В результате исследования были выявлены проблемы, возникающие у таможенных органов при расследовании преступлений и предложены рекомендации по решению этих проблем.The object of the research is customs authorities as tool of providing of economic safety. The goal of the work is the identification of problems, which customs authorities face while the process of investigation of crimes in economic sphere and developing some recommendations aimed to raise the efficiency of customs authorities’ activity. In the researching process there was an analysis of the regulatory framework, which adjusts the customs authorities’ activity and the practice of investigation of crimes in economic sphere. As a result of the research some problems, which customs authorities face while the process of investigation, were revealed and there are some offers aimed to solve this problems

Sodium-Calcium Exchange Initiated by the Ca2+Transient An Arrhythmia Trigger Within Pulmonary Veins

ObjectivesThe hypothesis that an increased or prolonged Ca2+transient during an abbreviated action potential can give rise to early afterdepolarizations (EADs) and triggered arrhythmia by enhanced forward sodium-calcium (Na-Ca) exchange was examined.BackgroundBecause pulmonary veins have the shortest action potential of any cardiac tissue, we examined this hypothesis in canine pulmonary vein sleeves during interventions further shortening the action potential and increasing the calcium transient.MethodsExtracellular bipolar electrode, intracellular microelectrode, and isometric force (a surrogate marker for the Ca2+transient) recordings were obtained from superfused canine pulmonary veins.ResultsAn elevation and prolongation of the terminal phase of repolarization (EADs) were observed during interventions increasing contractile force; isoproterenol or norepinephrine (3.2 × 10−11to 3.2 × 10−7M), hypothermia, and pacing (post-extrasystolic potentiation, post-pacing pause). The EAD formation was prevented by ryanodine (10 μM) or reversed by transiently increasing [Ca2+]ofrom 1.35 to 5 mM (inhibition of forward Na-Ca exchange). Pacing-induced EADs were enhanced by re-introduction of normal Tyrode solution (Na+= 130 mM) after substitution of 30 mM NaCl with 30 mM LiCl (stimulation of forward Na-Ca exchange). With norepinephrine or isoproterenol (3.2 × 10−8M) + acetylcholine (10−7M) (to enhance the Ca2+transient and further shorten the abbreviated action potential, respectively), tachycardia-pause initiated arrhythmia (1,132 ± 153 beats/min) lasting >1 s was observed. Rapid firing was prevented by either suppression of the Ca2+transient (ryanodine) or transiently increasing [Ca2+]o.ConclusionsThe data show EAD formation in superfused canine pulmonary veins, enhanced by an increased Ca2+transient and increased Na-Ca exchange current. With subsequent shortening of the action potential with acetylcholine, tachycardia-pause triggers rapid firing within the PV sleeve

Prevention and Reversal of Atrial Fibrillation Inducibility and Autonomic Remodeling by Low-Level Vagosympathetic Nerve Stimulation

ObjectivesWe hypothesized that autonomic atrial remodeling can be reversed by low-level (LL) vagosympathetic nerve stimulation (VNS).BackgroundPreviously, we showed that VNS can be antiarrhythmogenic.MethodsThirty-three dogs were subjected to electrical stimulation (20 Hz) applied to both vagosympathetic trunks at voltages 10% to 50% below the threshold that slowed sinus rate or AV conduction. Group 1 (n = 7): Programmed stimulation (PS) was performed at baseline and during 6-h rapid atrial pacing (RAP). PS allowed determination of effective refractory period (ERP) and AF inducibility measured by window of vulnerability (WOV). LL-VNS was continuously applied from the 4th to 6th hours. Group 2 (n = 4): After baseline ERP and WOV determinations, 6-h concomitant RAP+LL-VNS was applied. Sustained AF was induced by injecting acetylcholine (ACh) 10 mM into the anterior right ganglionated plexus (Group 3, n = 10) or applying ACh 10 mM to right atrial appendage (Group 4, n = 9).ResultsGroup 1: The ERP progressively shortened and the ΣWOV (sum of WOV from all tested sites) progressively increased (p < 0.05) during 3-h RAP then returned toward baseline during 3-h RAP+LL-VNS (p < 0.05). Group 2: 6-h concomitant RAP+LL-VNS did not induce any significant change in ERP and ΣWOV. Group 3 and Group 4: AF duration (AF-D) and cycle length (AF-CL) were markedly altered by 3-h LL-VNS (Group 3: baseline: AF-D = 389 ± 90 s, AF-CL = 45.1 ± 7.8 ms; LL-VNS: AF-D = 50 ± 15 s, AF-CL = 82.0 ± 13.7 ms [both p < 0.001]; Group 4: baseline: AF-D = 505 ± 162 s, AF-CL = 48.8 ± 6.6 ms; LL-VNS: AF-D = 71 ± 21 s, AF-CL = 101.3 ± 20.9 ms [both p < 0.001]).ConclusionsLL-VNS can prevent and reverse atrial remodeling induced by RAP as well as suppress AF induced by strong cholinergic stimulation. Inhibition of the intrinsic cardiac autonomic nervous system by LL-VNS may be responsible for these salutary results

Inducibility of Paroxysmal Atrial Fibrillation by Isoproterenol and its Relation to the Mode of Onset of Atrial Fibrillation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73118/1/j.1540-8167.2007.01089.x.pd

Ganglionated Plexi Modulate Extrinsic Cardiac Autonomic Nerve Input Effects on Sinus Rate, Atrioventricular Conduction, Refractoriness, and Inducibility of Atrial Fibrillation

ObjectivesThis study sought to systematically investigate the interactions between the extrinsic and intrinsic cardiac autonomic nervous system (ANS) in modulating electrophysiological properties and atrial fibrillation (AF) initiation.BackgroundSystematic ganglionated plexi (GP) ablation to evaluate the extrinsic and intrinsic cardiac ANS relationship has not been detailed.MethodsThe following GP were exposed in 28 dogs: anterior right GP (ARGP) near the sinoatrial node, inferior right ganglionated plexi (IRGP) at the junction of the inferior vena cava and atria, and superior left ganglionated plexi (SLGP) near the junction of left superior pulmonary vein and left pulmonary artery. With unilateral vagosympathetic trunk stimulation (0.6 to 8.0 V, 20 Hz, 0.1 ms in duration), sinus rate (SR), and ventricular rate (VR) during AF were compared before and after sequential ablation of SLGP, ARGP, and IRGP.ResultsThe SLGP ablation significantly attenuated the SR and VR slowing responses with right or left vagosympathetic trunk stimulation. Subsequent ARGP ablation produced additional effects on SR slowing but not VR slowing. After SLGP + ARGP ablation, IRGP ablation eliminated VR slowing but did not further attenuate SR slowing with vagosympathetic trunk stimulation. Unilateral right and left vagosympathetic trunk stimulation shortened the effective refractory period and increased AF inducibility of atrium and pulmonary vein near the ARGP and SLGP, respectively. The ARGP ablation eliminated ERP shortening and AF inducibility with right vagosympathetic trunk stimulation, whereas SLGP ablation eliminated ERP shortening but not AF inducibility with left vagosympathetic trunk stimulation.ConclusionsThe GP function as the “integration centers” that modulate the autonomic interactions between the extrinsic and intrinsic cardiac ANS. This interaction is substantially more intricate than previously thought