Narrow Complex Research Articles

Rectangular Slot based Beam Focusing Dual-Band Phase Gradient Metasurface

This study proposes method for enhancing the performance of previously developed or produced weapon systems without developing new detection equipment by using Phase Gradient Metasurfaces(PGMS). Metasurface has been studied and utilized a lot to improve the detection performance of inorganic systems, but its utilization is low due to its narrow bandwidth and complex structure. To address some of these limitations, dual-band power focusing PGMS is proposed. Its frequency independent unit cell characteristic enables creating metasurface that concentrates signals in dual-band. The designed PGMS was validated through near-field and far-field measurement, confirming signal concentration at the specified focal length and improved gain in the dual bands.

Untethered & Stiffness-Tunable Ferromagnetic Liquid Robots for Cleaning Thrombus in Complex Blood Vessels.

Thrombosis is a significant threat to human health. However, the existing clinical treatment methods have limitations. Magnetic soft matter is used in the biomedical field for years, and ferromagnetic liquids exhibit tunable stiffness and on-demand movement advantages under magnetic fields. In this study, a ferromagnetic liquid robot (FMLR) is developed and applied it to thrombus removal in complex blood vessels. The FMLR consisted of Fe3O4 magnetic nanoparticles and dimethyl silicone oil. The FMLR can pass through a narrow complex maze through shape deformation by tailoring the intensity and direction of the external magnetic field. Finite element simulation analysis is used to validate the mechanism of controllable FMLR movements. Importantly, the storage modulus of FMLR can be tuned from 0.1 to 2018Pa by varying the external magnetic intensity, ensuring its effectiveness in removing rigid and stubborn thrombi present on the vascular walls. Toward medical robotic applications, FMLR can be used in telerobotic neurointerventional. Experiments demonstrating the capability of FMLR to remove thrombi in the ear veins of rabbits are conducted. This study introduces an efficient approach for thrombus elimination, broadening the utilization of FMLRs within the realm of clinical medicine.

Clinical, electrocardiographic, and diagnostic imaging features and outcomes in cats with electrocardiographic diagnosis of ventricular pre-excitation: a retrospective study of 23 cases (2010–2022)

Introduction/ObjectivesVentricular pre-excitation (VPE) occurs when atrial electrical impulses prematurely excite the ventricles through an aberrant muscle bundle known as an accessory pathway (AP). Orthodromic atrioventricular reciprocating tachycardia is a re-entrant, narrow complex supraventricular tachycardia (SVT), maintained through retrograde conduction over an AP. The study aimed to describe patient signalments, clinical signs, electrocardiographic (ECG) and diagnostic imaging features, treatments, prognostic variables, and outcomes in cats with ECG diagnosis of VPE. AnimalsTwenty-three cats diagnosed with VPE between January 2010 and August 2022 were included in this study. Materials and MethodsThis was a multicenter, retrospective study with twenty-three cats diagnosed with VPE between January 2010 and August 2022. Ventricular pre-excitation diagnosis was based on ECG evidence of shortened PR interval, delta wave, and prolonged QRS duration. The median survival time (MST) was estimated by the Kaplan-Meier curve. Log-rank tests were performed to assess for an association between clinical signs or presence of structural heart disease on the MST. ResultsFourteen (60.8%) cats with VPE also had SVT documented on ECG, with 7 of 14 with ECG confirmation of orthodromic atrioventricular reciprocating tachycardia. Four (17.4%) cats had suspected AP-mediated tachyarrhythmia based on associated clinical signs. Common presenting signs included collapse (15/23; 65.2%) and respiratory distress (14/23; 60.8%). Five (21.7%) cats were asymptomatic. Heart rate during SVT ranged from 310 to 420 bpm (median: 375 bpm). Initial treatment included atenolol (10/18), sotalol (5/18), diltiazem (2/18), and amiodarone (1/18). From the date of diagnosis, MST was 1872 days (5.1 years). ConclusionsThe majority of cats with VPE also had symptomatic SVT. The prognosis for cats with VPE is considered good with an MST of greater than five years.

Two Arrhythmias, One Diagnosis, All from Surface ECGs

A 48-year-old male with known supraventricular tachycardia presented with wide complex tachycardia and he was cardioverted. The patient was initially diagnosed with both ventricular tachycardia and supraventricular tachycardia. After reviewing electrocardiograms, a correct diagnosis of orthodromic atrioventricular reciprocating tachycardia with left-sided accessory pathway was made which was confirmed and successfully ablated in subsequent electrophysiological study. Not all wide complex tachycardias are ventricular tachycardia. If the rate of narrow complex supraventricular tachycardia becomes slower with the development of a bundle branch block, it is diagnostic for the presence and participation of the ipsilateral accessory pathway, which is called Coumel’s law

Safety of adenosine for pediatric tachyarrhythmia treatment in the emergency department: a multi-hospital 10-year cross-sectional study

BackgroundSupraventricular tachycardia is the most common dysrhythmia in children. Initial vagal maneuvers are successful less than half of the time. Adenosine, a potent AV nodal blocker with a short half-life, is recommended as first line pharmacotherapy. Minor side effects from adenosine are common, but report of serious side effects such as sustained ventricular tachycardia, torsades de pointes, syncope or hypotension are confined to small case series or studies greater than 20 years old. We aimed to specifically identify the incidence of serious side effects of adenosine in children in the emergency department.MethodsBetween 2002 and 2022, all children less than 18 years old who received adenosine for tachyarrhythmia treatment in two emergency departments were included. The electronic record was reviewed for demographic information, patient history, treatments given, and side effects or complications were observed. Electrocardiograms before, during and after adenosine administration were reviewed.Results77 patients met inclusion criteria. There were 74 patients with an initial rhythm of typical SVT. The other three patients included one with a junctional rhythm, one with atrial fibrillation, and one with an undetermined narrow complex tachycardia. 49 patients had cardiac rhythm monitoring during adenosine administration. 17 of these patients had three or more consecutive ventricular beats following adenosine, however no patients required treatment. No patients had syncope. One patient had brief hypotension after adenosine that normalized without intervention. Four patients were electrically cardioverted after adenosine, all for persistent dysrhythmias: two for persistent SVT with hypotension, one for atrial fibrillation and one for an undetermined rhythm. Twelve patients were placed on continuous antiarrhythmic medication for persistent SVT. Age, gender, prior SVT history, initial adenosine dose, and need for additional doses were not significant risk factors for a prolonged sinus pause or greater than two ventricular beats.ConclusionsAdenosine treatment in typical supraventricular tachycardia in pediatric patients is safe.

What an anesthesiologist should know about pediatric arrhythmias.

Identifying and treating pediatric arrhythmias is essential for pediatric anesthesiologists. Pediatric patients can present with narrow or wide complex tachycardias, though the former is more common. Patients with inherited channelopathies or cardiomyopathies are at increased risk. Since most pediatric patients present for anesthesia without a baseline electrocardiogram, the first identification of an arrhythmia may occur under general anesthesia. Supraventricular tachycardia, the most common pediatric tachyarrhythmia, represents a broad category of predominately narrow complex tachycardias. Stimulating events including intubation, vascular guidewire manipulation, and surgical stimulation can trigger episodes. Valsalva maneuvers are unreliable as treatment, making adenosine or other intravenous antiarrhythmics the preferred acute therapy. Reentrant tachycardias are the most common supraventricular tachycardia in pediatric patients, including atrioventricular reciprocating tachycardia (due to a distinct accessory pathway) and atrioventricular nodal reentrant tachycardia (due to an accessory pathway within the atrioventricular node). Patients with ventricular preexcitation, often referred to as Wolff-Parkinson-White syndrome, have a wide QRS with short PR interval, indicating antegrade conduction through the accessory pathway. These patients are at risk for sudden death if atrial fibrillation degenerates into ventricular fibrillation over a high-risk accessory pathway. Automatic tachycardias, such as atrial tachycardia and junctional ectopic tachycardia, are causes of supraventricular tachycardia in pediatric patients, the latter most typically noted after cardiac surgery. Patients with inherited arrhythmia syndromes, such as congenital long QT syndrome, are at risk of developing ventricular arrhythmias such as polymorphic ventricular tachycardia (Torsades de Pointes) which can be exacerbated by QT prolonging medications. Patients with catecholaminergic polymorphic ventricular tachycardia are at particular risk for developing bidirectional ventricular tachycardia or ventricular fibrillation during exogenous or endogenous catecholamine surges. Non-selective beta blockers are first line for most forms of long QT syndrome as well as catecholaminergic polymorphic ventricular tachycardia. Anesthesiologists should review the impact of medications on the QT interval and transmural dispersion of repolarization, to limit increasing the risk of Torsades de Pointes in patients with long QT syndrome. This review explores the key anesthetic considerations for these arrhythmias.

Frequency of Atypical AVNRT in Patients Presenting with Narrow Complex Tachycardia

ABSTRACT Objective: To determine the frequency of atypical AVNRT in patients presenting with Narrow Complex Tachycardia. Study Design: Descriptive Cross Sectional Place and Duration of Study: Department of Cardiology, MTI-Hayatabad Medical Complex, Peshawar, from March, 2021 to March, 2022. Methodology: Ninety-three patients of either aged 30 to 80 years diagnosed with narrow complex tachycardia by consultant cardiac electrophysiologist on ECG showing QRS duration of less than 120 milliseconds were included in this study. Patients were managed as per standard protocol which included comprehensive clinical evaluation such as patient history, physical examination and invasive electrophysiological study for the diagnosis and characterization of atypical Atrioventricular Nodal Reentrant Tachycardia (AVNRT). Results: A total of ninety-three patients were studied with mean age of 43.08 years (SD = 9.07). Among the participants, 58.1% were male, while 41.9% were female. Majority of patients had Slow-Fast AVNRT (7.5%) followed by Fast-Slow AVNRT (3.2%), and Slow-Slow AVNRT in 2.2% patients. Conclusion: This study underscored the importance of gender-specific variations in the prevalence of different AVNRT types and highlighted the impact of gender as a potential influencing factor in the manifestation of specific types of AVNRT within the study population.

Narrow complex tachycardia with alternating atrial activation: What is the mechanism?

Narrow complex tachycardia with alternating atrial activation: What is the mechanism?

Assessment of current pediatric electrocardiogram (ECG) interpretation practices

BackgroundDespite improvements in digital electrocardiograms (ECGs), current standard of care requires physician confirmation. Mismatched expectations between ordering providers and ECG readers, often pediatric cardiologists and electrophysiologists (EPs), are common, especially since there are no standardized practices for pediatric ECG reading. ObjectivesThe aim of this study was to understand current practices in pediatric ECG reading. MethodsAn electronic survey was sent to members of the Pediatric and Congenital Electrophysiology Society (PACES). Participation was optional; results were recorded from 12/19/22–1/9/23. Only complete and non-duplicate entries were included. ResultsA total of 127 responses were received, 93 were analyzed. Most responses were from centers in North America (n = 65, 70 %), including the US (n = 58, 62 %), Canada (n = 6, 6 %), and Mexico (n = 1, 1 %). The remaining were from Europe (n = 18, 19 %), Asia (n = 7, 8 %), Australia (n = 2, 2 %), and South America (n = 1, 1 %). Most (n = 46, 49 %) were from small centers (0–25 ECGs read per day), 27 respondents (29 %) were from medium centers (26–50 ECGs read per day), 20 respondents (22 %) were from large centers (>50 ECGs read per day). The majority (n = 65, 70 %) reported >3 readers/day for inpatient and emergency department ECGs. 49 % (n = 46) of centers read ECGs >2 times/day on weekdays with more variable practice on weekends. For critical/time sensitive findings, most centers (n = 90, 97 %) used verbal communication +/− the EMR. There was consensus (≥50 % agreement) that the following findings are critical/time sensitive: QTc >500 ms, T-wave alternans, narrow complex tachycardia, wide complex tachycardia, pre-excited atrial fibrillation, focal ischemic changes, second degree heart block type II, complete heart block, and pacemaker malfunction. ConclusionReading practices are variable. Critical/time sensitive findings are most often communicated verbally, however, there is no agreed upon standard. There was consensus in critical/time-sensitive findings. Improved understanding of common practices and resource allocation may lead to increased consistency in pediatric ECG reading.

Adenosine response to narrow complex tachycardia: Who blinks first?

Adenosine response to narrow complex tachycardia: Who blinks first?

Machine-learning guided differentiation between photoplethysmography waveforms of supraventricular and ventricular origin

Abstract Aims To test, whether a neural network-based classifier could aid in distinguishing photoplethysmographic (PPG) pulse waveforms of ventricular from those of supraventricular origin. Methods Thirty patients undergoing invasive electrophysiological studies for documented narrow complex tachycardias between May and December 2021 at a university medical centre were included in the trial. PPG waveforms were recorded using a PPG wristband (Empatica E4) in parallel to 12-lead surface electrograms (ECGs) and intracardiac electrograms from diagnostic catheters. Pulse waves were then annotated to either supraventricular (sinus rhythm, atrial pacing) or ventricular origin (ventricular pacing) based on invasive electrogram recordings, ECGs and stimulation protocols. 21147 data sets were split into test, training and validation data sets and used to develop, train and validate a convolutional neural network (CNN) for classifying PPG waveforms according to their origin into sinus rhythm, atrial or ventricular pacing. Results Datasets were complete for 27 patients. 74% were female and median age was 53 (range 18, 78) years, median BMI was 27±5, 19% had arterial hypertension, 11% had diabetes and 15% had coronary artery disease. During the electrophysiological study, typical AV-nodal re-entrant tachycardias could be induced in 63% of patients, 15% had inducible atrial tachycardias and the other patients had no inducible tachyarrhythmias. Our CNN-based classifier was able to correctly predict the origins of pulse waves in 95±1% for sinus rhythm, 96±1% for atrial paced rhythms and 95±1% for ventricular rhythms. Conclusion A neural network-based classifier trained on ground truth PPG data obtained by using invasive EP measurements for annotation could accurately predict atrial or ventricular origin from PPG waveforms alone.Graphical abstract

Research on Online Measurement Method for Small Workpiece Circular Holes Based on Machine Vision

<p>In modern manufacturing, due to the narrow format, short size, and complex surface structure of small-sized workpieces, automatic detection of surface defects, dimensions, etc. on small-sized workpieces faces difficulties, making it difficult to meet the requirements of fully automated production lines. Especially, there is no good solution to the problem of high-precision automatic measurement of geometric features of circles and arcs on small-sized workpieces. This article takes the engine end cover circular hole thermal component as the research object, builds a hardware platform for image acquisition of small-sized workpieces based on machine vision, proposes an online size measurement method for small-sized circular holes, and realizes the measurement of the position size and aperture size of small-sized product shell workpieces. In order to achieve the above methods, this article builds a visual detection hardware system and describes a detailed machine vision hardware selection scheme. Then, the images collected by the system are preprocessed, including image denoising, image correction, and image feature extraction. Then, for the processed images, an improved Hough transform fitting method is used to obtain the online size of features. In order to visualize the results, the detection system and software are designed according to the actual application scenario. The overall scheme of this article is efficient and reasonable, and the detection result error is within a reasonable range.</p> <p> </p>

Case report: Para Hisian Atrial Tachycardia

Case report: Para Hisian Atrial Tachycardia

Ectopic Atrial Tachycardia in Children: A Literature Review

Introduction: Ectopic atrial tachycardia (EAT) is an unusual and potentially risky arrhythmia that can result in left ventricular dysfunction if not properly managed. In adults, EAT is mainly caused by diseased atrial myocardium and responds poorly to antiarrhythmic drugs. The characteristics of EAT in children might be different from those in adults because of their immature myocardium and the different electrophysiologic characteristics of their conduction tissue. Purpose: To present the data on the natural history and treatment of EAT in children. Material and method: The study material consisted of reviewed articles on the topic found on the globally accepted electronic databases, PubMed, Medline and Google Scholar regarding the Ectopic atrial tachycardia in children and its treatment. Results: The diagnosis of atrial ectopic tachycardia is based on the presence of a narrow complex tachycardia (in the absence of aberrancy or pre-existing bundle branch block) with visible P waves at an inappropriately rapid rate. The rates range from 120 to 300 beats per minute (bpm) and are typically higher than 200 bpm, although physiologic rates may be observed. EAT in children without underlying heart disease can be effectively treated using antiarrhythmic drugs. Spontaneous resolution of EAT after medication in children was frequent (75%). Conclusion: EAT in children without underlying heart disease can be effectively treated using antiarrhythmic drugs. The results of studies suggest that a stepwise approach using digoxin, a beta-blocker, and a class I antiarrhythmic drug may be the most effective treatment for EAT

Grid-Based Non-Uniform Probabilistic Roadmap-Based AGV Path Planning in Narrow Passages and Complex Environments

In this paper, we propose a Grid-based Non-uniform Probability Density Sampling Probabilistic Roadmap algorithm (GN-PRM) in response to the challenges of difficult sampling in narrow passages and low-probability map generation in traditional Probabilistic Roadmap algorithms (PRM). The improved algorithm incorporates grid-based processing for map segmentation, employing non-uniform probability density sampling based on the different attributes of each block to enhance sampling probability in narrow passages. Additionally, considering the computational cost and frequent ineffective searches in traditional PRM algorithms during pathfinding, this paper optimizes the time required for query route planning by altering connection strategies to improve the algorithm’s runtime. Finally, the simulation results indicate that, with a reduction of over 50% in undirected line segments and a reduction of over 85% in runtime, the GN-PRM algorithm achieves a 100% success rate in complex planning scenarios with a sampling point value of K = 500. In comparison, the traditional PRM algorithm has a success rate of no more than 10%, with a sampling point value of K = 500.

Performance modeling of flame-assisted fuel cells based on a swirl burner

Aiming at the problems of a narrow operating range and complex modeling of Flame-assisted Fuel Cells (FFCs), an FFC system based on a swirl burner is proposed, and neural network algorithms are used to construct the prediction model for the polarization curve of the FFC system. First, the output voltage and power values of the FFC system are measured under different working conditions, and various experimental parameters are collected to form a dataset; second, the correlation analysis method is used to screen out the parameters that are highly correlated with the output voltage as the input variables of the neural network; finally, the prediction model of the polarization curve is constructed, and back propagation (BP), long short term memory, and 1D-CNN algorithms are chosen to examine the applicability of various neural networks for the FFC system. The experimental and polarization characteristic curve prediction results show that the FFC system can obtain a maximum output voltage of 10.6 V and power of 7.71 W. The average relative errors of the three algorithms are 5.23%, 4.08%, and 6.19%, respectively, with the BP neural network algorithm showing the best generalization ability. The study provides support for the application of the FFC system in aerospace and other fields.

Alternative routes to intravenous procedural sedation to cardiovert unstable wide complex tachycardia – case report and review of literature

Background: Cardioversion is the treatment of choice in an unstable patient with arrhythmia. It requires analgesia and sedation, which is usually given via intravenous route. However, when there is a failure to get vascular access, alternatives routes to intravenous (IV) sedation and analgesia are needed. Case Presentation: A 59 year old male patient was presented to the emergency department (ED) complaining of chest pain and palpitation. His electrocardiogram (ECG) showed new onset rapid narrow complex atrial fibrillation, which then converted to wide complex tachycardia. Initially, the patient remained hemodynamically stable, but his blood pressure dropped, when cardioversion was indicated. In this case, intranasal (IN) and intraosseous (IO) routes were used, both of which are uncommon to be used for sedation in an unstable patient. The sedatives bioavailability and dosage via non intravenous (non-IV) routes are not commonly used, hence, literature was reviewed to find out the appropriate sedative dosage via non-IV routes specifically in IN and IO route for moderate sedation in ED, to facilitate procedures like cardioversion. Conclusion: It was believed that IN and IO routes are good alternatives to intravenous routes when timely vascular access can't be secured and when emergency medication administration is required.

Alternative routes to intravenous procedural sedation to cardiovert unstable wide complex tachycardia – case report and review of literature

Background: Cardioversion is the treatment of choice in an unstable patient with arrhythmia. It requires analgesia and sedation, which is usually given via intravenous route. However, when there is a failure to get vascular access, alternatives routes to intravenous (IV) sedation and analgesia are needed. Case Presentation: A 59 year old male patient was presented to the emergency department (ED) complaining of chest pain and palpitation. His electrocardiogram (ECG) showed new onset rapid narrow complex atrial fibrillation, which then converted to wide complex tachycardia. Initially, the patient remained hemodynamically stable, but his blood pressure dropped, when cardioversion was indicated. In this case, intranasal (IN) and intraosseous (IO) routes were used, both of which are uncommon to be used for sedation in an unstable patient. The sedatives bioavailability and dosage via non intravenous (non-IV) routes are not commonly used, hence, literature was reviewed to find out the appropriate sedative dosage via non-IV routes specifically in IN and IO route for moderate sedation in ED, to facilitate procedures like cardioversion. Conclusion: It was believed that IN and IO routes are good alternatives to intravenous routes when timely vascular access can't be secured and when emergency medication administration is required.

Detection of supraventricular arrhythmias with apple watch

Abstract Introduction With the recent developments in wearable technology, detecting arrhythmias has become much easier. Although smartwatches are commonly used to detect patients with atrial fibrillation, there is no consensus on their efficiency in detecting supraventricular tachycardias (SVT). Methods & Results Electrophysiological procedures were performed on 47 patients that have been previously documented to have SVT by a 12-lead ECG. All patients had sinus rhythm before the procedure. A narrow complex SVT which patients had at least once was induced by electrophysiological methods. Induced SVTs were recorded with a 6th-generation Apple Watch as one rhythm strip. Among the induced tachycardias, 27 typical AVNRT, 11 AVRT and 9 AT/AFLwere diagnosed. These records obtained from the smartwatch were evaluated by 3 cardiology residents and 3 attending cardiologists. Evaluated records were predicted among attending physicians with a minimum sensitivity of 66.0% and maximum sensitivity of 76.6%. Among residents, minimum and maximum sensitivity rates were 68.1% and 74.5%, respectively. The reliability between residents and attendings was assessed separately using Fleiss’s kappa method. The interrater reliability was found to be Kappa=0.465 (p<0.001), 95% CI (0.30-0.63) within the group of residents and Kappa=0.519, (p<0.001), 95% CI (0.35-0.68) within the group of attendings. Overall Kappa value was 0.417 (p<0.001), 95% CI (0.34-0.49), indicating a significantly important moderate level of agreement (p<0.001). Conclusion To the best of our knowledge, this is the first study showing how accurately clinicians can interpret the recording of SVTs with wearable devices such as smart watches, whose definitive diagnosis was made invasively by electrophysiological study. As presented in our study, induced, and subsequently recorded SVTs were predicted with high sensitivity and a moderate reliability rate. Adoption of smartwatches could significantly limit the delays in diagnosis and treatment of patients admitted to the hospitals with complaints of palpitations that cannot be documented.Statistics

Abstract 15372: The Lewis Lead

The Lewis lead is a modified ECG configuration that can enhance the amplitude of the atrial electrical activity and is useful when the atrial activity cannot be discerned in the standard ECG. The configuration involves applying the right arm electrode on the manubrium, left arm electrode to the 5th intercostal space on the right sternal border, left leg electrode over the right lower costal margin and right leg electrode in the standard position. The ECG is then interpreted in lead I and II. Herein we present a case where the Lewis lead aided in the diagnosis of complete heart block with underlying atrial fibrillation. Case Presentation: A 75 year old female with severe tricuspid regurgitation was admitted for tricuspid valve replacement. She had previous paroxysmal atrial fibrillation status post pulmonary vein isolation. The preoperative ECG revealed normal sinus rhythm. Postoperatively, ECG demonstrated a narrow complex ventricular rhythm at 70 beats per minute. No atrial activity could be clearly discerned (Image 1). The epicardial atrial wire placed intraoperatively was not functioning, therefore atrial electrogram could not be obtained. It was unclear from repeat ECGs if there was sinus arrest or atrial fibrillation in the atria. The Lewis lead was then utilized and revealed underlying atrial fibrillation (Image 1); together, this was consistent with atrial fibrillation and complete heart block with a junctional escape rhythm. The rhythm did not recover and there was progressive conduction system disease with widening of the QRS and episodes of severe bradycardia. She underwent pacemaker implantation. Discussion: By utilizing the Lewis lead we were able to establish the atrial rhythm and differentiate between atrial fibrillation and sinus arrest. The Lewis lead can also help narrow the differential for wide complex tachycardia by magnifying the p wave, thus making it easier to detect ventriculoatrial dissociation, a hallmark feature of ventricular tachycardia.