Supraventricular Tachycardia Research Articles

Diagnosis of Narrow QRS Tachycardia

Narrow QRS tachycardia is a common clinical condition characterized by a heart rate exceeding 100 beats per minute and a QRS complex duration of less than 120 ms. This article provides an overview of the diagnostic approach to narrow QRS tachycardia, focusing on the differentiation between various supraventricular tachycardias, such as atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), atrial tachycardia (AT), and sinus tachycardia. The discussion includes an analysis of the presenting symptoms, electrocardiographic (ECG) findings, and the use of vagal maneuvers and pharmacological agents in diagnosis.

Conflicting responses with simultaneous atrioventricular pacing. What is the mechanism?

A 60-year-old woman presented with recurrent episodes of palpitations, documented short RP, narrow QRS tachycardia and absence of preexcitation in the electrocardiogram during sinus rhythm. During an electrophysiology study, programmed stimulation induced a narrow QRS tachycardia with cycle length of 380 ms, VA interval of 164 ms and earliest atrial activation in the His region. Ventricular overdrive pacing failed to entrain the atrium even with isoprenaline infusion and atrial burst pacing repeatedly terminated the tachycardia. Difference in AH interval with pacing and SVT was 27 msec. Simultaneous atrial and ventricular pacing was done with atrial pacing from the high right atrium and showed a His signal as the first return electrogram suggestive of atrioventricular nodal reentrant tachycardia (AVNRT). The manoeuvre was repeated with atrial pacing from the proximal coronary sinus and showed an atrial signal as the first return electrogram suggestive of atrial tachycardia (AT). What is the explanation for the conflicting results of the two pacing maneuvers?

Direct Comparison of Methods to Differentiate Wide Complex Tachycardias: Novel Automated Algorithms Versus Manual ECG Interpretation Approaches.

Differentiating wide complex tachycardias (WCTs) into ventricular tachycardia (VT) and supraventricular wide tachycardia via 12-lead ECG interpretation is a crucial but difficult task. Automated algorithms show promise as alternatives to manual ECG interpretation, but direct comparison of their diagnostic performance has not been undertaken. Two electrophysiologists applied 3 manual WCT differentiation approaches (ie, Brugada, Vereckei aVR, and VT score). Simultaneously, computerized data from paired WCT and baseline ECGs were processed by 5 automated WCT differentiation algorithms (WCT Formula, WCT Formula II, VT Prediction Model, Solo Model, and Paired Model). The diagnostic performance of automated algorithms was compared with manual ECG interpretation approaches. A total of 212 WCTs (111 VT and 101 supraventricular wide tachycardia) from 104 patients were analyzed. WCT Formula demonstrated superior accuracy (85.8%) and specificity (87.1%) compared with Brugada (75.2% and 57.4%, respectively) and Vereckei aVR (65.3% and 36.4%, respectively). WCT Formula II achieved higher accuracy (89.6%) and specificity (85.1%) against Brugada and Vereckei aVR. Performance metrics of the WCT Formula (accuracy 85.8%, sensitivity 84.7%, and specificity 87.1%) and WCT Formula II (accuracy 89.8%, sensitivity 89.6%, and specificity 85.1%) were similar to the VT score (accuracy 84.4%, sensitivity 93.8%, and specificity 74.2%). Paired Model was superior to Brugada in accuracy (89.6% versus 75.2%), specificity (97.0% versus 57.4%), and F1 score (0.89 versus 0.80). Paired Model surpassed Vereckei aVR in accuracy (89.6% versus 65.3%), specificity (97.0% versus 75.2%), and F1 score (0.89 versus 0.74). Paired Model demonstrated similar accuracy (89.6% versus 84.4%), inferior sensitivity (79.3% versus 93.8%), but superior specificity (97.0% versus 74.2%) to the VT score. Solo Model and VT Prediction Model accuracy (82.5% and 77.4%, respectively) was superior to the Vereckei aVR (65.3%) but similar to Brugada (75.2%) and the VT score (84.4%). Automated WCT differentiation algorithms demonstrated favorable diagnostic performance compared with traditional manual ECG interpretation approaches.

Safety and feasibility of cardiac electrophysiology procedures in ambulatory surgery centers

BackgroundDespite their improved safety, by and large, cardiac electrophysiology procedures including catheter ablation (CA), are presently performed in hospital outpatient departments. ObjectiveThis large multicenter study investigated the safety and outcomes associated with various cardiac electrophysiology procedures performed at 6 ambulatory surgery centers (ASCs), primarily during the coronavirus disease 2019 pandemic under the Center for Medicare and Medicaid Services Hospitals Without Walls program. MethodsWe retrospectively analyzed the outcomes from consecutive electrophysiology procedures performed in ASCs with same-day discharge, including transesophageal echocardiography, cardioversion, cardiac implantable electronic device (CIED) implantation, electrophysiology studies, and CA for atrial fibrillation (AF), atrial flutter (AFL)/supraventricular tachycardia, ventricular premature complexes (VPCs), and atrioventricular node. ResultsAltogether, 4037 procedures were performed, including 779 transesophageal echocardiography/cardioversion procedures (19.3%), 1453 CIED implantation procedures (36.0%), 26 electrophysiology studies (0.6%), and 1779 CA procedures (44.1%) for AF (75.4%), AFL/supraventricular tachycardia (18.8%), VPC (4.7%), and atrioventricular node (1.1%). Overall, 80.2% of CA procedures were for left-sided atrial arrhythmias (AF/atypical AFL) requiring transseptal catheterization. Left-sided VPC ablation procedures (42.2%) were performed using a transseptal/retrograde approach. Adverse event rates were low, but comparable between CIED implantation and CA (0.76% vs 0.73%; P = .93), as were the incidences of urgent/unplanned postprocedure hospitalization (0.48% vs 0.45%; P = .89), respectively. Moreover, the adverse event rates in ASCs vs hospital outpatient departments did not differ for CIED (0.76% vs 0.65%; P = .71) or CA (0.73% vs 0.80%; P = .79). ConclusionThe results from this large multicenter study suggest that ASCs represent a safe and effective setting to perform a variety of cardiac electrophysiology procedures including CA. These findings bear important implications for healthcare delivery and policy.

Wolff-Parkinson-White Syndrome in the Preterm Neonate.

Wolff-Parkinson-White (WPW) syndrome is a rare cardiac condition arising from abnormal embryologic development of the annulus fibrosus in combination with the cardiac conduction system. The abnormality results in the development of accessory pathways and preexcitation changes which can provoke episodes of tachyarrhythmias. The most common presentation of WPW syndrome is supraventricular tachycardia. Beyond customary abortive therapy, chronic management strategies vary based upon timing and clinical severity of the initial disease presentation. Prompt diagnosis and rate control have a dramatic impact on the outcomes of morbidity and mortality. The purpose of this article is to present a case study of a preterm infant who manifested with WPW syndrome. Additionally, the article will explore the pathophysiology of WPW syndrome and the timing and presentation of common clinical manifestations of the disease, along with current diagnostic and treatment strategies to achieve optimal patient outcomes in the neonatal population.

Nocturnal Cardiac Arrhythmias in Heart Failure With Obstructive and Central Sleep Apnea

Both obstructive and central sleep apnea (OSA and CSA) may contribute to nocturnal cardiac arrhythmias (NCA). Data on the prevalence of clinically important nocturnal atrial and ventricular arrythmias in patients with heart failure with reduced ejection fraction (HFrEF) and obstructive (OSA) or central sleep apnea (CSA) are scarce. In a cohort of patients with HFrEF, how does the prevalence of NCA compare among those with OSA, CSA and those with no to mild sleep apnea? Is the severity of OSA or CSA associated with atrial and ventricular NCA? This cross-sectional analysis is an ancillary study of the ADVENT-HF trial. We compared the prevalence of NCA (excessive supraventricular ectopic activity [ESVEA], defined as premature atrial complexes [PAC] ≥30/h or supraventricular tachycardia ≥20 beats); atrial fibrillation/flutter [AF]; and >10 premature ventricular complexes [PVC/h]) on ECGs from polysomnograms of HFrEF patients between those with OSA (apnea-hypopnea index [AHI≥15]), those with CSA (AHI≥15/h) and those with no to mild sleep apnea (AHI<15, control). Compared to controls (n=76), the prevalence of ESVEA was higher in patients with OSA (n=430) and CSA (n=150), 0%, 9% and 12%, respectively. The prevalences of AF in the control, OSA and CSA groups were 9%, 17% and 27%, and of >10 PVC/h 45%, 59% and 63%, respectively. In multivariable regression analyses PAC/h was associated with OSA severity (obstructive AHI) [22.4% increase per 10 events/h (95% confidence interval: 5.2; 42.3); p=0.009], but neither obstructive nor central AHI were associated with AF or >10 PVC/h. In patients with HFrEF, the prevalences of nocturnal ESVEA, AF and PVC >10/h were higher in those with, than in those without OSA or CSA, and OSA severity was related to the burden of nocturnal atrial ectopy. Severity of OSA or CSA were not significantly related to AF or >10 PVC/h.

Failure to treat ventricular tachycardia or ventricular fibrillation by implantable cardioverter-defibrillators

BackgroundNormally functioning implantable cardioverter-defibrillators (ICDs) with intact lead systems occasionally fail to deliver therapy for ventricular tachycardia/fibrillation (VT/VF) or deliver it only after clinically significant delays (failure-to-treat). ObjectiveWe aimed to investigate ICD failure-to-treat VT/VF in a large patient cohort. MethodsWe searched the US Food and Drug Administration's online Manufacturer and User Facility Device Experience (MAUDE) database from 2019 to 2023 for manufacturer-verified reports in which normally functioning ICDs failed to treat VT/VF. ResultsWe identified 854 reports classified as deaths (n = 96 [11.2%]), injuries (n = 585 [68.5%]), or malfunctions (n = 173 [20.4%]) for normally functioning ICDs. The most common causes were misclassification as supraventricular tachycardia (SVT) or atrial fibrillation (AF; 54.8%), undersensing (21.1%), and failure to satisfy programmed rate/duration criteria (8.7%). Most events caused by misclassification as SVT/AF (89.5%) and failure to satisfy rate/duration criteria (70.3%) were VT; most caused by undersensing were either VF (54.4%) or not specified as VT or VF (19.4%). Undersensing caused 65.6% of deaths, although it represented only 21.1% of reports. In the United States, the number of reports increased faster than that of ICD patients. ConclusionIn the largest reported series of failure-to-treat VT/VF by normally functioning ICDs, the most common cause was misclassification of VT as SVT/AF; the most common cause of death was undersensing of VF. Although relatively few patients with normally functioning ICDs experience failure-to-treat VT/VF, the absolute number of verified MAUDE reports suggests that more work is needed to quantify the magnitude of the problem, to identify root causes, and to develop solutions.

A 72-year-old Woman with Dyspnea and Thrombocytosis

&lt;p&gt;原發性血小板增多症的臨床表徵並不典型且早期診斷不易，往往多數病人於診斷前已發生動靜脈血栓形成及出血併發症。本個案一位72歲女性，有高血壓及胃食道逆流病史並按時門診追蹤服藥，五天前注射新冠疫苗後，呼吸喘、乾咳併胸悶至診所就醫未改善，於急診初步診斷急性支氣管炎。入院後感心悸且胸悶，藉由病史詢問、檢驗及理學檢查，顯示心肌酵素正常但心電圖呈現陣發性心室上心搏過速，安排冠狀動脈血管攝影攝影後排除急性心肌梗塞，但呼吸急促未見好轉呈現低血氧，經胸腔電腦斷層為肺栓塞。疑似新冠疫苗後引起的免疫併發症，直到右手食指及中指末梢腫、痛且發紺症狀出現，筆者再次重新檢視病史資料，發現血小板異常，透過骨髓穿刺切片是發現巨核細胞（megakaryocyte）增生，病理報告判斷為骨髓增生性腫瘤，基因檢測結果為JAK2V617F 突變，最後確診是原發性血小板增多症併發肺栓塞，接受Hydroxyurea合併口服抗凝血劑治療，症狀改善且血小板數值趨於穩定。藉此案例分享提醒當發現病人有不明血栓產生時須考慮將相關血液疾病列入鑑別診斷，期能及早發現疾病，掌握治療時機。&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;&lt;p&gt;The clinical symptoms of essential thrombocythemia are not typical and early diagnosis is difficult.Most patients have arteriovenous thrombosis and bleeding complications before diagnosis. In this case, a 72-year-old woman had a history of hypertension and gastroesophageal reflux and was taking medication regularly at the outpatient clinic. After being injected with the COVID-19 vaccine five days ago, her breathing, dry cough, and chest tightness did not improve when she went to the clinic. She was initially diagnosed with acute bronchitis in the emergency department. After being admitted to the hospital, she felt palpitations and chest tightness. The medical history, examination and physical examination showed that myocardial enzymes were normal, but the electrocardiogram showed Parox-ysmal supraventricular tachycardia. Coronary angiography was arranged to rule out acute myocardial infarction, but the shortness of breath persisted with hypoxemia, and the computed tomography of the chest showed pulmonary embolism. Immune complications caused by the COVID-19 vaccine were suspected, symptoms of swelling, pain and cyanosis appeared in the distal part of the right index fin-ger and middle finger appeared. The author re-examined the medical history data and found abnormal platelets. Through bone marrow aspiration and sectioning, megakaryocyte hyperplasia was found. Pa-thology report determined that the patient suffered from myeloproliferative neoplasm, and the genetic test result was the JAK2V617F mutation. The patient was finally diagnosed with essential thrombocythe-mia complicated by pulmonary embolism. She was treated with Hydroxyurea combined with oral an-ticoagulants. The symptoms improved and the platelet level stabilized. This case serves as a reminder that when a patient is found to have unknown thrombosis, related blood diseases must be considered in the differential diagnosis, so that the disease can be detected early and proper treatments can be pro-vided.&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Exploring the impact of electrocardiographic parameters on the risk of common arrhythmias: a two-sample Mendelian randomization study.

Observational studies have shown that heart rate (HR), heart rate variability (HRV), P-wave terminal force, P-wave duration, T-wave amplitude and PR interval are associated with risk factors for atrial fibrillation (AF) or bradycardia. Arrhythmias are associated with many causes of hospitalization. However, observational studies are susceptible to confounding factors that have not yet been identified. The objective of this study was to clarify the causal relationships by Mendelian randomization analysis. We conducted a two-sample and multivariate Mendelian randomization (MVMR) analysis using genome-wide association study (GWAS) data from a European population to assess the total and direct causal effects of HR, three HRV traits, P-wave terminal force, P-wave duration, T-wave top amplitude in five-lead modes, and the PR interval on the risk of AF (N=191,205), bradycardia (N=463,010), and supraventricular tachycardia (SVT) (N=463,010). The results of the univariate MR analysis revealed the following significant causal effects: the higher the genetically predicted PR interval, the lower the risk of AF; the higher the HR and T-wave top amplitude (aVR leads and V3 + V4 + aVL leads), the lower the risk of bradycardia; and the higher HR and the lower PR interval, the higher the risk of SVT. The multivariate MR results indicated that the HRV_standard deviation of the normal-to-normal (SDNN) interval had an independent causal effect on the risk of AF [odds ratio (OR): 0.515; 95% confidence interval (CI): 0.278-0.954; P=0.03], and the T-wave top amplitude in the aVR leads (OR: 0.998; 95% CI: 0.996-0.999; P<0.001) and the HRV_SDNN (OR: 0.988; 95% CI: 0.976-1.000; P=0.045) had independent causal effects on the risk of bradycardia. The HRV_SDNN had an independent causal effect on AF, while the HRV_SDNN and T-wave top amplitude in the aVR leads had independent causal effects on bradycardia, which suggests that some of the electrocardiographic parameters have preventive effects on the incidence of AF and bradycardia.

The nightmare of catheter ablation in a young male with incessant supraventricular tachycardia.

A case report involving incessant multi-types of supraventricular tachycardia and acute decompensated heart failure required a rescuing electrophysiology study and ablation. Ventricular fibrillation occurred due to coronary spasm, complicating the deteriorating heart. However, aggressive therapies, including extracorporeal support and the timely elimination of the culprit accessory pathway, successfully resolved the patient's condition.

A Rapid Response Mobile Application Improves First-Year Resident Clinical Performance During Simulated Care Events: A Randomized Controlled Trial.

Rapid response teams (RRTs) are critical to the timely and appropriate management of acutely decompensating patients. In the academic setting, the vital role of RRT leader is often filled by a junior resident physician who may lack the necessary medical knowledge and experience. Cognitive aids help improve guideline adherence and may support resident performance as they transition into leadership roles. This study evaluated the impact of a rapid response mobile application on intern performance during simulated rapid response events. This randomized controlled trial compared the performance of interns in two simulated rapid response scenarios with and without access to the rapid response mobile application. The scenarios included anaphylaxis and supraventricular tachycardia (SVT). Simulations were video recorded and coded by trained raters. Interns in all specialties at our institution. Outcomes included (1) time to ordering critical medications (epinephrine and adenosine), (2) overall clinical performance using a checklist-based performance measure, and (3) usability of the mobile application. Enrollment and data collection occurred between November 2022 and February 2023. Forty-four interns from 12 specialties were randomized to the intervention group (N = 22) and the control group (N = 22). Time to order critical medications was significantly reduced in the intervention group compared to control for anaphylaxis (P < 0.005) and SVT (P < 0.005). The intervention group had significantly higher performance scores compared to the control group for the anaphylaxis portion (P < 0.006). Usability scores for the rapid response toolkit were good. Access to a rapid response mobile application improved the quality of care administered by interns during two simulated rapid response scenarios as determined by a decrease in time to ordering critical medications and improved performance scores. The intervention group found the mobile application to be usable. This work adds to existing literature supporting the use of technology-based cognitive aids to improve patient care.

Preclinical Safety Evaluation of Etripamil Nasal Spray in Cynomolgus Macaques (Macaca fascicularis) to Assess for Safety in Patients With Paroxysmal Supraventricular Tachycardia.

Etripamil is a calcium channel blocker currently in Phase 3 trials for the treatment of paroxysmal supraventricular tachycardia (PSVT). Systemic and local toxicity following once-weekly intranasal administration of etripamil was evaluated in cynomolgus macaques to support clinical development. Groups of animals (N = 8, 4 males and 4 females) were administered etripamil into the left nostril weekly at dose levels of 0 (vehicle), 1.9, 3.8, or 5.7mg/kg/dose for 26 doses. Persistence, reversibility, and progression of findings were examined following a 28-day recovery period. Clinical signs were transient and were related to the intranasal administration (e.g., nasal discharge, sneezing, etc.) of etripamil. There were no macroscopic or systemic microscopic findings at any dose. Etripamil-related adaptive and reactive local changes affecting the nasal cavity, larynx, and nasopharynx were observed at ≥1.9mg/kg/dose. Minimal to severe dose-dependent nasal epithelial damage was observed, mainly affecting respiratory and transitional epithelium. Following the 28-day recovery period, microscopic changes were confined to the left nasal cavity and nasopharynx. These changes were significantly lower in incidence and severity, with noticeable reversal of the adaptive and reactive changes, indicating partial to complete recovery of the epithelial lining. Based on the lack of systemic toxicity and the minimal and transient nasal changes, the systemic, no observable adverse effect level (NOAEL) of etripamil in monkeys was the high dose, 5.7mg/kg/dose. The NOAEL for local toxicity was 1.9mg/kg/dose. Collectively, these data support further study of etripamil in human trials as a potential treatment for PSVT.

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.

Antiarrhythmic drugs in the present day

Cardiac arrhythmias cause asignificant proportion of hospitalizations and physician contacts worldwide. By using antiarrhythmic drugs, cardiac arrhythmias can be effectively treated and the frequency of recurrences reduced. Atrial fibrillation and heart failure represent diseases in which antiarrhythmic drugs are more often used on along-term basis. The aim of this article is to provide an overview of the most common antiarrhythmic drugs and their uses as well as to provide recommendations for adequate handling and use, especially in the outpatient setting. In addition to long-term use, some antiarrhythmic drugs are also administered for the acute management of supraventricular or ventricular tachycardia. Relevant contraindications, side effects and interactions must be considered, meaning that patients should be followed up when using these potent drugs. This article shows in detail what to consider when using antiarrhythmic drugs in order to ensure not only effective but also safe treatment.

Doing a double take: when transthoracic echocardiography fails for mitral valve annuloplasty ring endocarditis with Streptococcus pyogenes: a case report

BackgroundThis case highlights several complications of a late and rare presentation of culture-negative Streptococcus pyogenes endocarditis of a previously repaired mitral valve with an annuloplasty ring including recurrent cardioembolic strokes, which was initially missed on transthoracic echocardiography.Case presentationA 66-year-old Caucasian female with prior mitral valve prolapse status post mitral valve annuloplasty and left atrial appendage occlusion, followed by two strokes, presented with supraventricular tachycardia that resolved spontaneously. During an inpatient admission, she developed symptoms of another stroke, and imaging studies were suggestive of recurrent cardioembolic phenomenon. Additional workup revealed two small intra-atrial masses adherent to the mitral annuloplasty ring missed on prior evaluation for recurrent stroke. She underwent surgical repair in the setting of a chronic culture-negative infectious endocarditis with Streptococcus pyogenes and recovered well with no further cardioembolic phenomenon.ConclusionThis case serves to highlight the importance of having a higher index of suspicion in any cardiac prosthesis patient for endocarditis when presenting with symptoms such as recurrent stroke, arrhythmias, and abnormal cardiac lab work. It also demonstrates the need for appropriate imaging with transthoracic echocardiography followed by transesophageal echocardiography and reviews surgical indications to diagnose and treat culture-negative endocarditis.

SVT quest: The adventure diagnosing narrow QRS tachycardia.

In the field of cardiac electrophysiology, there is a universal desire: the discovery of a flawless diagnostic maneuver for supraventricular tachycardias (SVTs). This is not merely a wish but a shared odyssey. To improve diagnostic accuracy and achieve sufficient sensitivity and specificity, numerous diagnostic maneuvers have been proposed. However, each has its limitations and prompts a search for new diagnostic techniques. This continuous cycle of discovery and refinement, which we titled "SVT Quest" is reviewed in chronological sequence. This adventure in diagnosing narrow QRS tachycardia unfolds in 3 steps: Step 1 involves differentiating atrial tachycardia from other SVTs based on the observations such as V-A-V or V-A-A-V response, ΔAA interval, VA linking, the last entrainment sequence, and response to the atrial extrastimulus. Step 2 focuses on differentiating orthodromic reciprocating tachycardia from atrioventricular nodal reentrant tachycardia based on the observations such as tachycardia reset upon the premature ventricular contraction during His refractoriness, uncorrected/corrected postpacing interval, differential ventricular entrainment, orthodromic His capture, transition zone analysis, and total pacing prematurity. Step 3 characterizes the concealed nodoventricular/nodofascicular pathway and His-ventricular pathway-related tachycardia based on observations such as V-V-A response, ΔatrioHis interval, and paradoxical reset phenomenon. There is no single diagnostic maneuver that fits all scenarios. Therefore, the ability to apply multiple maneuvers in a case allows the operator to accumulate evidence to make a likely diagnosis. Let's embark on this adventure!

Accuracy of a Single-Lead ECG Device for Diagnosis of Cardiac Arrhythmias Compared Against Cardiac Electrophysiology Study

Single-lead electrocardiogram (ECG) devices may allow detection and diagnosis of cardiac rhythms. However, data on their accuracy for detecting cardiac arrhythmias beyond atrial fibrillation are limited. We aimed to determine the accuracy of the AliveCor KardiaMobile (AC) (AliveCor Inc, Mountain View, CA, USA) for the diagnosis of arrhythmias against gold standard cardiac electrophysiology study (EPS). Patients undergoing clinically indicated EPS underwent simultaneous rhythm recording with an AC, standard 12-lead ECG, and EP catheters for intracardiac electrograms. Rhythms recorded during EPS were classified based on electrogram, 12-lead ECG, and clinical findings. Blinded reviewers provided differential diagnoses for the single-lead AC tracings; a separate reviewer compared diagnoses made between the AC tracings and EPS findings. In 49 patients, 843 cardiac rhythms were captured during 502 AC recordings. Analysis of tracings containing sinus rhythm (n=273) returned an overall accuracy of 92%, with sensitivity and specificity values of 93% and 92%, respectively. Accuracy for tracings per rhythm was atrial fibrillation 91% (n=51); supraventricular tachycardia accuracy was 89% (n=191), ventricular tachycardia 91% (n=198), ventricular fibrillation 98% (n=11), and asystole 100% (n=5). Accuracy for supraventricular ectopy was 93% (n=28) and for premature ventricular complexes was 91% (n=86). Overall accuracy was 94% for solitary rhythms and 93% in tracings from patients with baseline bundle branch block. When compared against the gold standard EPS diagnosis, the interpretation of arrhythmias recorded by an AliveCor single-lead ECG device had reasonable diagnostic accuracy.

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

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

Outcome of Neonatal Registry Through Electronic Medical Registry at Neonatal Intensive Care Units, Children's Hospital of Ain Shams University

Abstract Background The neonatal mortality rate is 19 deaths per 1000 live births worldwide. Studies have shown that neonatal registry network systems can provide the necessary data for establishing evidence- based strategies to decrease the complications in high-risk neonates and consequently reduce neonatal mortality rate. Aim of the Work To determine the frequency and distribution of neonatal critical illnesses in Neonatal Intensive Care Unit (NICU) of Ain Shams University. Patients and Methods This descriptive study was conducted in NICU, Children's Hospital, Ain Shams University. The data collected from initiated neonatal registry through electronic medical record to reach sample size number (381) patients. The current study was conducted after approval by the Department of Pediatrics, and the local Ethics and Research Committee, Faculty of Medicine, Ain Shams University. Results The mean ± (SD) age at admission was 5.52 ± 6.9 days, gestational age was 36.19 ± 2.47 weeks, more than half of our patients were males (55.6%) and females represented in (44.4%). Two- thirds (64.2%) of our participants were full term, and preterm were only (35.7%). The main etiology of NICU admission was respiratory disease (35.7%), followed by neonatal sepsis (25.2%), neonatal jaundice (21%), congenital anomalies (12.3%), CNS diseases (6.8%), inborn errors of metabolism (1%) and mortality rate was 10.5%. Four cases had inborn errors of metabolism in the form of: Maple syrup urine disease (one case), organic academia (one cases) and 2 cases referred to genetic clinic for further assessment. Congenital heart diseases in our study was reported in (7.9%) of neonates. The main etiology among them was reported in following order: PDA / pulmonary hypertension (26.7%), VSD (13.3%), Fallot tetralogy (10%), transposition of great arteries (10%), supraventricular tachycardia (6.7%) then many etiologies represented in 3.3% as Ebstein anomaly, right single ventricle, heart block, pulmonary artery stenosis, arrhythmia, tricuspid atresia and left hypoplastic heart disease. Conclusion This study showed the ability of the electronic medical record to store large amounts of data which creates a potential for information overload in the intensive care (ICU) setting. This will stimulate and facilitate research on neonatal critical illness and its management, mortality and morbidity outcomes of neonates admitted to NICUs in Children's Hospital, Ain Shams University, Egypt.

Rare Variant in MRC2 Associated With Familial Supraventricular Tachycardia and Wolff-Parkinson-White Syndrome.

Accessory pathways are a common cause of supraventricular tachycardia (SVT) and can lead to sudden cardiac death in otherwise healthy children and adults when associated with Wolff-Parkinson-White syndrome. The goal of this study was to identify genetic variants within a large family with structurally normal hearts affected by SVT and Wolff-Parkinson-White syndrome and determine causality of the gene deficit in a corresponding mouse model. Whole exome sequencing performed on 2 distant members of a 3-generation family in which multiple members were affected by SVT or Wolff-Parkinson-White pattern (preexcitation) on ECG identified MRC2 as a candidate gene. Serial electrocardiograms, intracardiac electrophysiology studies, echocardiography, optical mapping studies, and histology were performed on both Mrc2 mutant and WT (wild-type) mice. A rare HET (heterozygous) missense variant c.2969A>G;p.Glu990Gly (E990G) in MRC2 was identified as the leading candidate gene variant segregating with the cardiac phenotype following an autosomal-dominant Mendelian trait segregation pattern with variable expressivity. In vivo electrophysiology studies revealed reentrant SVT in E990G mice. Optical mapping studies in E990G mice demonstrated abnormal retrograde conduction, suggesting the presence of an accessory pathway. Histological analysis of E990G mouse hearts showed a disordered ECM (extracellular matrix) in the annulus fibrosus. Finally, Mrc2 knockdown in human cardiac fibroblasts enhanced accelerated cell migration. This study identified a rare nonsynonymous variant in the MRC2 gene in individuals with familial reentrant SVT, Wolff-Parkinson-White ECG pattern, and structurally normal hearts. Furthermore, Mrc2 knock-in mice revealed an increased incidence of reentrant SVT and bypass tract formation in the setting of preserved cardiac structure and function.