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BACKGROUND: 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. METHODS: 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. RESULTS: 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%). CONCLUSIONS: Automated WCT differentiation algorithms demonstrated favorable diagnostic performance compared with traditional manual ECG interpretation approaches. [ABSTRACT FROM AUTHOR]

Background: This systematic review explores the effects of landiolol administration in individuals presenting with supraventricular tachyarrhythmia (SVT) and concurrent left ventricular dysfunction, without being septic or in a peri-operative period. Methods: We systematically searched PubMed, Cochrane, Web of Science, and Scopus databases, retrieving a total of 15 eligible studies according to prespecified eligibility criteria. Results: Patients treated with landiolol experienced a substantial reduction in heart rate (HR) (mean HR reduction: 42 bpm, 95% confidence intervals (CIs): 37–47, I2 = 82%) and were more likely to achieve the target HR compared to those receiving alternative antiarrhythmic therapy (pooled odds ratio (OR): 5.37, 95% CIs: 2.87–10.05, I2 = 0%). Adverse events, primarily hypotension, occurred in 14.7% of patients receiving landiolol, but no significant difference was observed between the landiolol and alternative antiarrhythmic receiving groups (pooled OR: 1.02, 95% CI: 0.57–1.83, I2 = 0%). No significant difference was observed between the two groups concerning sinus rhythm restoration (pooled OR: 0.97, 95% CI: 0.25–3.78, I2 = 0%) and drug discontinuation due to adverse events (pooled OR: 5.09, 95% CI: 0.6–43.38, I2 = 0%). Conclusion: While further research is warranted, this systematic review highlights the potential benefits of landiolol administration in the management of SVTs in the context of left ventricular dysfunction. [ABSTRACT FROM AUTHOR]

BACKGROUND: The accuracy of noninvasive arrhythmia source localization using a forward-solution computational mapping system has not yet been evaluated in blinded, multicenter analysis. This study tested the hypothesis that a computational mapping system incorporating a comprehensive arrhythmia simulation library would provide accurate localization of the site-of-origin for atrial and ventricular arrhythmias and pacing using 12-lead ECG data when compared with the gold standard of invasive electrophysiology study and ablation. METHODS: The VMAP study (Vectorcardiographic Mapping of Arrhythmogenic Probability) was a blinded, multicenter evaluation with final data analysis performed by an independent core laboratory. Eligible episodes included atrial and ventricular: tachycardia, fibrillation, pacing, premature atrial and ventricular complexes, and orthodromic atrioventricular reentrant tachycardia. Mapping system results were compared with the gold standard site of successful ablation or pacing during electrophysiology study and ablation. Mapping time was assessed from time-stamped logs. Prespecified performance goals were used for statistical comparisons. RESULTS: A total of 255 episodes from 225 patients were enrolled from 4 centers. Regional accuracy for ventricular tachycardia and premature ventricular complexes in patients without significant structural heart disease (n=75, primary end point) was 98.7% (95% CI, 96.0%-100%; P

Background Ultra-high-density mapping enables detailed mechanistic analysis of atrial reentrant tachycardia but has yet to be used to assess circuit conduction velocity (CV) patterns in adults with congenital heart disease. Methods and Results Circuit pathways and central isthmus CVs were calculated from consecutive ultra-high-density isochronal maps at 2 tertiary centers over a 3-year period. Circuits using anatomic versus surgical obstacles were considered separately and pathway length 85% predicted isthmus block in all cases. Over >1 year of follow-up, arrhythmia-free survival was better for homogeneous CV patterns (90% versus 57%; P=0.04). Conclusions Ultra-high-density mapping-guided CV analysis distinguishes atrial reentrant patterns in adults with congenital heart disease with surgical obstacles producing slower and smaller circuits. Very slow central isthmus CV may be essential for atrial tachycardia maintenance in small circuits, and non-isthmus conduction time in tachycardia appears to be useful for rapid assessment of postablation conduction block.

Purpose This article, the first in a 2-part review, aims to reinforce current literature on the pathophysiology of cardiac arrhythmias and various evidence-based treatment approaches and clinical considerations in the acute care setting. Part 1 of this series focuses on atrial arrhythmias. Summary Arrhythmias are prevalent throughout the world and a common presenting condition in the emergency department (ED) setting. Atrial fibrillation (AF) is the most common arrhythmia worldwide and expected to increase in prevalence. Treatment approaches have evolved over time with advances in catheter-directed ablation. Based on historic trials, heart rate control has been the long-standing accepted outpatient treatment modality for AF, but the use of antiarrhythmics is often still indicated for AF in the acute setting, and ED pharmacists should be prepared and poised to help in AF management. Other atrial arrhythmias include atrial flutter (AFL), atrioventricular nodal reentry tachycardia (AVNRT), and atrioventricular reentrant tachycardia (AVRT), which warrant distinction due to their unique pathophysiology and because each requires a different approach to utilization of antiarrhythmics. Atrial arrhythmias are typically associated with greater hemodynamic stability than ventricular arrhythmias but still require nuanced management according to patient subset and risk factors. Since antiarrhythmics can also be proarrhythmic, they may destabilize the patient due to adverse effects, many of which are the focus of black-box label warnings that can be overreaching and limit treatment options. Electrical cardioversion for atrial arrhythmias is generally successful and, depending on the setting and/or hemodynamics, often indicated. Conclusion Atrial arrhythmias arise from a variety of mechanisms, and appropriate treatment depends on various factors. A firm understanding of physiological and pharmacological concepts serves as a foundation for exploring evidence supporting agents, indications, and adverse effects in order to provide appropriate care for patients. [ABSTRACT FROM AUTHOR]

Background: Supraventricular tachycardia (SVT), manifested as rapid and regular heartbeat, is the most frequent symptomatic tachyarrhythmia requiring medical intervention in children. SVT occurs in 1 in every 250-1,000 children. The heart rate can be as high as 180 beats/minute in children and 220 beats/minute in Infants. Evidence suggests that the primary dose of adenosine should be given as 0.1 mg/kg, administered in an intravenous bolus with a dose up to 6 mg. If the primary dose is insufficient, then the amount is increased by 0.1 mg/kg-0.2 mg/kg to a maximum of 12 mg. Our case demonstrates the response to adenosine after the third dose. Case presentation: A 12-year-old boy, previously diagnosed with recurrent SVT, presented with a complaint of palpitation for the last 30 minutes. There was no obvious trigger for his palpitation on history and examination. He was conscious, well looking with normal blood pressure, and good perfusion. We started the management in accordance with pediatric advanced life support guidelines, in which we noted a partial response after the administration of the second dose of adenosine. Subsequently, a third dose of adenosine of 0.2 mg/kg was administered, terminating SVT and regaining a normal sinus rhythm in the patient. Conclusion: After reviewing recent evidence regarding stable SVT management and adenosine side effects, we found that there is no evidence limiting the use of adenosine to only two doses, especially in a case of short or minimal response following the second dose. [SJEMed 2022; 3(2.000): 166-170]

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Background Existing data on predictors of late mortality and prevention of sudden cardiac death after atrial switch repair surgery for D-transposition of the great arteries (D-TGA) are heterogeneous and limited by statistical power. Methods and Results We conducted a systematic review and meta-analysis of 29 observational studies, comprising 5035 patients, that reported mortality after atrial switch repair with a minimum follow-up of 10 years. We also examined 4 additional studies comprising 105 patients who reported rates of implantable cardioverter-defibrillator therapy in this population. Average survival dropped to 65% at 40 years after atrial switch repair, with sudden cardiac death accounting for 45% of all reported deaths. Mortality was significantly lower in cohorts that were more recent and operated on younger patients. Patient-level risk factors for late mortality were history of supraventricular tachycardia (odds ratio [OR] 3.8, 95% CI 1.4-10.7), Mustard procedure compared with Senning (OR 2.9, 95% CI 1.9-4.5) and complex D-TGA compared with simple D-TGA (OR 4.4, 95% CI 2.2-8.8). Significant risk factors for sudden cardiac death were history of supraventricular tachycardia (OR 4.7, 95% CI 2.2-9.8), Mustard procedure (OR 2.2, 95% CI 1.1-4.1), and complex D-TGA (OR 5.7, 95% CI 1.8-18.0). Out of a total 124 implantable cardioverter-defibrillator discharges over 330 patient-years in patients with implantable cardioverter-defibrillators for primary prevention, only 8% were appropriate. Conclusions Patient-level risk of both mortality and sudden cardiac death after atrial switch repair are significantly increased by history of supraventricular tachycardia, Mustard procedure, and complex D-TGA. This knowledge may help refine current selection practices for primary prevention implantable cardioverter-defibrillator implantation, given disproportionately high rates of inappropriate discharges.

A five-year-old, female-spayed boxer was referred for frequent and medically refractory paroxysmal supraventricular tachycardia. Diagnostic evaluation found no underlying structural heart or systemic diseases. Three-dimensional electroanatomical mapping and radiofrequency ablation were pursued. Activation mapping of normal sinus rhythm demonstrated the location of the sinus node in the posterolateral region of the right atrium. Activation mapping of the tachyarrhythmia identified a centrifugal activation pattern originating from the right atrium at the posterolateral aspect of the tricuspid valve orifice, suggestive of focal atrial tachycardia. A total of 10 ablation lesions were delivered to the earliest activation site. The dog recovered without complications and no recurrence of supraventricular tachycardia was noted on subsequent follow-ups. [ABSTRACT FROM AUTHOR]

Abnormalities of the cardiac rhythm are relatively common in children, with an estimated incidence of almost 1 in 4000 births. Most of these are supraventricular, and about half of children will experience their first episode as an infant. Symptoms, particularly in younger children, may be hard to detect. Delay in diagnosis can lead to ventricular dysfunction, heart failure and acute collapse. This short review provides an overview of the types of cardiac arrhythmias commonly encountered in children, provides practical advice for diagnosis, including the utility of different types of cardiac monitoring devices and outlines the management options. [ABSTRACT FROM AUTHOR]

The genetic basis of supraventricular and ventricular ectopy (SVE, VE) remains largely uncharacterized, despite established genetic mechanisms of arrhythmogenesis. To identify novel genetic variants associated with SVE/VE in ancestrally diverse human populations, we conducted a genome-wide association study of electrocardiographically identified SVE and VE in five cohorts including approximately 43,000 participants of African, European and Hispanic/Latino ancestry. In thirteen ancestry-stratified subgroups, we tested multivariable-adjusted associations of SVE and VE with single nucleotide polymorphism (SNP) dosage. We combined subgroup-specific association estimates in inverse variance-weighted, fixed-effects and Bayesian meta-analyses. We also combined fixed-effects meta-analytic t-test statistics for SVE and VE in multi-trait SNP association analyses. No loci reached genome-wide significance in trans-ethnic meta-analyses. However, we found genome-wide significant SNPs intronic to an apoptosis-enhancing gene previously associated with QRS interval duration (FAF1; lead SNP rs7545860; effect allele frequency = 0.02; P = 2.0 × 10-8) in multi-trait analysis among European ancestry participants and near a locus encoding calcium-dependent glycoproteins (DSC3; lead SNP rs8086068; effect allele frequency = 0.17) in meta-analysis of SVE (P = 4.0 × 10-8) and multi-trait analysis (P = 2.9 × 10-9) among African ancestry participants. The novel findings suggest several mechanisms by which genetic variation may predispose to ectopy in humans and highlight the potential value of leveraging pleiotropy in future studies of ectopy-related phenotypes.

The physiological changes during pregnancy predispose a woman for the development of new-onset or recurrent arrhythmia. Supraventricular arrhythmia is the most common form of arrhythmia during pregnancy and, although often benign in nature, can be concerning. We describe three complex cases of supraventricular arrhythmia during pregnancy and review the currently available literature on the subject. In pregnancies complicated by arrhythmia, a plan for follow-up and both maternal and fetal monitoring during pregnancy, delivery and post partum should be made in a multidisciplinary team. Diagnostic modalities should be used as in non-pregnant women if there is an indication. All antiarrhythmic drugs cross the placenta, but when necessary, medical treatment should be used with consideration to the fetus and the mother's altered pharmacodynamics and kinetics. Electrical cardioversion is safe during pregnancy, and electrophysiological study and catheter ablation can be performed in selected patients, preferably with zero-fluoroscopy technique. Sometimes, delivering the fetus (if viable) is the best therapeutic option. In this review, we provide a framework for the workup and clinical management of supraventricular arrhythmias in pregnant women, including cardiac, obstetric and neonatal perspectives. [ABSTRACT FROM AUTHOR]

Knowledge of the anatomy of the 'conduction tissues' of the heart is a 20th century phenomenon. Although controversies still continue on the topic, most could have been avoided had greater attention been paid to the original descriptions. All cardiomyocytes, of course, have the capacity to conduct the cardiac impulse. The tissues specifically described as 'conducting' first generate the cardiac impulse, and then deliver it in such a fashion that the ventricles contract in orderly fashion. The tissues cannot readily be distinguished by gross inspection. Robust definitions for their recognition had been provided by the end of the first decade of the 20th century. These definitions retain their currency. The sinus node lies as a cigar-shaped structure subepicardially within the terminal groove. There is evidence that it is associated with a paranodal area that may have functional significance. Suggestions of dual nodes, however, are without histological confirmation. The atrioventricular node is located within the triangle of Koch, with significant inferior extensions occupying the atrial vestibules and with septal connections. The conduction axis penetrates the insulating plane of the atrioventricular junctions to continue as the ventricular pathways. Remnants of a ring of cardiomyocytes observed during development are also to be found within the atrial vestibules, particularly a prominent retroaortic remnant, although that their role has still to be determined. Application of the initial criteria for nodes and tracts shows that there are no special 'conducting tissues' in the pulmonary venous sleeves that might underscore the abnormal rhythm of atrial fibrillation. [ABSTRACT FROM AUTHOR]

Background: Individuals with supraventricular tachycardia (SVT) may face difficulties when making decisions about their treatment options. Purpose: To evaluate the decision support provided by a cardiovascular nurse to a patient experiencing decisional conflict about catheter ablation for SVT. Methods: In this Ottawa Decision Support Framework-guided case study, decision support was provided using decision coaching and a patient decision aid (PDA) and evaluated using the Decision Support Analysis Tool (DSAT)-10 and changes in the patient's Sure of myself; Understand information; Risk-benefit ratio; Encouragement (SURE) test. Results: The patient's SURE test score improved from 0/4 to 3/4 after the intervention. The patient chose not to have a catheter ablation, as the inconvenience of the procedure and perceived necessity were highly valued. The DSAT-10 revealed that high-quality decision support was provided. Implications for Practice: Decision coaching combined with a PDA may reduce decisional conflict and promote informed values-based decisions for people with SVT considering catheter ablation. [ABSTRACT FROM AUTHOR]

Objective: The role of age in clinical characteristics and catheter ablation outcomes of atrioventricular nodal re-entrant tachycardia (AVNRT) or orthodromic atrioventricular re-entrant tachycardia (AVRT) has been assessed in retrospective studies categorising age by arbitrary cut-offs, but contemporary analyses of age-related trends are lacking. We aimed to study the relationship of age with epidemiological, clinical features and catheter ablation outcomes of AVNRT and AVRT.Methods: We recruited 600 patients (median age 56 years, 60% female) with a confirmed diagnosis of AVNRT (n=455) or AVRT (n=145) by means of an electrophysiological study. They were interrogated for arrhythmia-related symptoms with a structured questionnaire and followed up to 1 year. We analysed age as a continuous variable using regression models and adjusting for relevant covariables.Results: Both typical and atypical forms of AVNRT upraised with age while AVRT decreased (p<0.001 by regression). Female sex predominance in AVNRT was not observed in older patients. Overall, these tachycardias became more symptomatic with ageing despite a longer tachycardia cycle length (p<0.001) and regardless of the presence of structural heart disease, with a higher proportion of dizziness, syncope, chest pain or dyspnoea (p<0.005 for all) and a lower presence of palpitations or neck pounding (p<0.001 for both). Age was not associated with catheter ablation acute success, periprocedural complications or 1-year recurrence rates (p>0.05 for all).Conclusions: Age, evaluated as a continuous variable, had a significant association with the clinical profile of patients with AVNRT and AVRT. Nevertheless, catheter ablation outcomes and complications were not significantly related to patients' age. [ABSTRACT FROM AUTHOR]

Introduction: Supraventricular tachycardia (SVT) is one of the arrhythmias that can occur in newborns. Most SVT incidents in the neonatal period are spontaneously resolved around the first year of life, but since tachycardia can frequently occur before complete resolution, appropriate medication use is required. However, no clear guidelines or consensus on the treatment of neonatal SVT have been established yet. Methods: From January 2011 to December 2021, demographic data and antiarrhythmic medications used were retrospectively analyzed for 18 newborns diagnosed with SVT at a single center. Results: A total of four medications (propranolol, amiodarone, flecainide, and atenolol) were used as maintenance therapy to prevent tachycardia recurrence, and propranolol was the most used, followed by amiodarone. Thirty-nine percent of the patients were controlled with monotherapy, but the remainder required two or more medications. The median period from medication initiation after diagnosis to the last tachycardia event was 15.5 days, and the median total duration of medication use was 362 days. None of the patients experienced any side effects of antiarrhythmic medications. The total duration of medication use was statistically significant according to the mechanism of SVT, and the usage time of the increased automaticity group was shorter than that of the re-entry group. Conclusion: Since most neonatal SVT resolves within 1 year, it is significant to provide prophylactic medication to prevent tachycardia recurrence at least until 1 year of age, and depending on the patient, the appropriate combination of medications should be identified. [ABSTRACT FROM AUTHOR]

Idiopathic left ventricular tachycardia (previously known as fascicular VT) is characterized by right bundle branch block (RBBB) left axis ventricular tachycardia (VT) with a relatively narrow QRS (120–140 ms) in young patients and sensitive to verapamil. Objective: To remind that not all tachyarrhythmias with relatively narrow QRS are derived from supraventricular. Cases: First case of 23 years old man with chief complain palpitation and presyncope with narrow QRS ventricular tachycardia electrocardiography (ECG). Second case of 16 years old man with chief complain palpitation with narrow QRS ventricular tachycardia ECG, both of them are getting better after administration of diltiazem and verapamil. Conclusions: Idiopathic left ventricular tachycardia is associated with presyncope, palpitation and was successfully terminated with verapamil. Medical management is variable in its outcomes and given the age of the population affected. Narrow QRS complex tachycardia not always from supraventricular, we should think about ventricular tachycardia especially ILVT if there is no structural heart disease.

BackgroundAccessory pathways can lie near or within the coronary sinus (CS). Radiofrequency catheter ablation of accessory pathways is a well-established treatment option, but this procedure can cause damage to adjacent coronary arteries.ObjectiveThe purpose of this study was to evaluate the anatomic relationship between the coronary arteries and the CS.MethodsRetrospective data of patients who underwent catheter ablation of supraventricular tachycardia between June 2011 and August 2013 was reviewed. In addition, detailed analysis of coronary computed tomographic angiography (CTA) data from 50 patients was performed.ResultsBetween June 2011 and August 2013, 427 patients underwent catheter ablation of supraventricular tachycardia, of whom 105 (age 28 ± 17 years, 60% male) had accessory pathway-mediated tachycardia. Of these, 23 patients had accessory pathways near the CS, and 60% (N = 14) underwent concurrent coronary angiography. In 4 patients, the posterolateral (inferolateral) branch (PLA) of the right coronary artery was in close proximity to the CS, and 2 patients (18%) had stenosis of the PLA at the site of ablation. On CTA at their closest proximity, the PLA was 1.9 ± 1.3 mm and the left circumflex artery (LCx) was 2.0 ± 0.8 mm from the body of the CS, in right and left coronary artery-dominant patients, respectively. CS ostium and PLA were 3.6 ± 1.9 mm apart. In left-dominant patients, LCx and CS ostium were 3.8 ± 1.2 mm apart.ConclusionThe PLA and LCx are in close proximity to the anteroinferior aspect of the CS ostium and proximal CS. The relationship of the CS and coronary arteries should be evaluated before ablation at these sites.

Ventricular preexcitation secondary to anterograde conduction through an accessory pathway was diagnosed in two Golden Retriever dogs. Both dogs demonstrated similar segmental myocardial thinning and systolic dyskinesia of the basal interventricular wall on echocardiography. These changes are widely recognised in people with ventricular preexcitation but have not been previously described in dogs. Ventricular preexcitation should be considered as a potential cause for segmental wall motion abnormalities in these two dogs. [ABSTRACT FROM AUTHOR]

Clinical case: 5-month-old female patient diagnosed with Ebstein’s Anomaly from the first day of life. She was referred to a pediatric cardiology center where she reported dilatation of the right atrium, tricuspid regurgitation, and atrial septal defect. Due to slow evolution and not having a surgical team, she was discharged. Reason for reporting: Report a patient with Ebstein´s anomaly with early diagnosis and a slow but unfavorable clinical evolution, without immediate surgery, due to the major complications that the malformation can cause, such as cyanosis and supraventricular tachycardia. Conclusion: Ebstein’s anomaly is a rare malformation that affects both sexes and of unknown etiology. The anatomical severities are varied, with differences in severity between patients, and early diagnosis and treatment are extremely important. [ABSTRACT FROM AUTHOR]

Supraventricular arrhythmias are frequent, and symptomatic patients often need medical therapy or catheter ablation. The recently published 2019 European Society of Cardiology (ESC) Guidelines for the management of patients with supraventricular tachycardia (SVT) give a comprehensive overview of current developments in the field and provides recommendations for the management of adults with SVT. In this paper, we briefly summarized major new recommendations and significant changes from the former ESC guideline published 16 years ago.

We present the case of a healthy 28-day-old female full-term neonate who was admitted to the neonatal intensive care unit for severe metabolic acidosis, hypoglycemia, and an initial sinus rhythm. The first diagnostic hypothesis was hypovolemic shock, and fluid resuscitation was started immediately. During fluid therapy, cardiovascular collapse occurred with supraventricular tachycardia. The latter was successfully treated with adenosine and beta-blockers. After 8 days, electrocardiography showed ventricular pre-excitation, and Wolff-Parkinson-White syndrome was diagnosed. A novel variant of the MYL2 gene that is related to hypertrophic cardiomyopathy and conduction defect was found after discharge. Cardiogenic shock should be considered, despite being a rare cause of shock in neonates. [ABSTRACT FROM AUTHOR]

Case: A 34-year-old woman with no significant past medical history presented to the hospital with sudden onset of palpitations with associated dyspnea and chest discomfort. She denied any similar previous episodes. Initial electrocardiogram (EKG) was consistent with a short R-P interval supraventricular tachycardia (SVT). Her transthoracic echocardiogram (TTE) revealed no structural abnormalities, TSH levels were normal, and urine drug screen was negative for any recreational drugs. However, the patient had been taking phentermine for weight loss.Discussion: The exact mechanism is not clear; however, we postulate that the sympathomimetic effects of phentermine likely contribute to SVT induction through enhanced AV nodal conduction or increased atrial ectopy. Conclusions: The only medication she was taking at home was phentermine, and the palpitations did not recur after discontinuation of the drug during follow-up. It is important to collect a thorough medication history when patients present with AV nodal reentrant tachycardia (AVNRT) or other SVT. [ABSTRACT FROM AUTHOR]

The article presents a case of a 62-year-old male who was rushed to the emergency department due to sudden onset palpitations and chest discomfort to discuss a unique case of supraventricular tachycardia (SVT) and its drug treatment called adenosine. Also cited are the possible adverse effects of adenosine like transient atypical atrioventricular (AV) block.

Supraventricular tachycardia (SVT) usually presents to the emergency department as a result of a combination of symptoms, including palpitations, dyspnea, and chest pain. Less frequent symptoms include lightheadedness, near-syncope, or syncope due to reduced cerebral perfusion. Accurate diagnosis of SVT guides acute treatment. Although many doctors are good at pattern recognition on electrocardiograms (ECGs), having a methodical approach to think through SVT is extremely helpful. [ABSTRACT FROM AUTHOR]

Fetal supraventricular tachycardia (SVT) and atrial flutter (AF) can be associated with significant morbidity and mortality. Digoxin is often used as first-line therapy but can be ineffective and is poorly transferred to the fetus in the presence of fetal hydrops. As an alternative to digoxin monotherapy, we have been using sotalol at presentation in fetuses with SVT or AF with, or at risk of, developing hydrops to attempt to achieve more rapid control of the arrhythmia. The present study was a retrospective review of the clinical, echocardiographic, and electrocardiographic data from all pregnancies with fetal tachycardia diagnosed and managed at a single center from 2004 to 2008. Of 29 affected pregnancies, 21 (16 SVT and 5 AF) were treated with sotalol at presentation, with or without concurrent administration of digoxin. Of the 21, 11 (6 SVT and 5 AF) had resolution of the tachycardia within 5 days (median 1). Six others showed some response (less frequent tachycardia, rate slowing, resolution of hydrops) without complete conversion. In 1 fetus with a slow response, the mother chose pregnancy termination. The 5 survivors with a slow response were all difficult to treat postnatally, including 1 requiring radiofrequency ablation as a neonate. One fetus developed blocked atrial extrasystoles after 1 dose of sotalol and was prematurely delivered for fetal bradycardia. Three grossly hydropic fetuses with SVT showed no response and died within 1 to 3 days of treatment. In conclusion, transplacental sotalol, alone or combined with digoxin, is effective for the treatment of fetal SVT and AF, with an 85% complete or partial response rate in our series.

The Task Force for the management of patients with supraventricular tachycardia of the European Society of Cardiology (ESC)Developed in collaboration with the Association for European Paediatric and Congenital Cardiology (AEPC)

Objective: This study set out to analyze the therapeutic options of patients with neonatal atrial flutter (AFL), considering the diagnostic methods available and the prognosis of these patients. Methodology: A retrospective study was performed by reviewing the medical records of a series of seven patients with atrial fibrillation (AF) diagnosed during fetal or neonatal period. The follow-up time of these patients ranged from 7 months to 3 years and 8 months (mean: 1 year). The clinical data for the diagnosis included sustained heart rate greater than 180 bpm, which was confirmed in all patients by a 12-lead electrocardiogram. Results: Four (57.1%) of the 7 patients studied were male. Most of the patients revealed cardiac arrhythmia during the intrauterine period when screened by fetal ultrasound in the third trimester of gestation (5 patients, i.e. 71.2%). Only the mother of Patient 2 was administered digoxin before childbirth. The atrial rate of the tachyarrhythmia revealed a mean of 375 bpm, with an increase of up to 500 bpm. Atrioventricular conduction presented a 2:1 ratio in all patients, with variations of 3:1 and 4:1 observed in Patients 1, 3 and 6. The ventricular rate ranged from 188 to 250 bpm. All patients revealed typical and counter-clockwise electrocardiogram characteristics. Synchronized electrical cardioversion was the treatment of choice in 6 patients (85.7%), with a dose of 1 J/kg. Conclusion: Early diagnosis, prior treatment, and synchronized electrical cardioversion indicate an excellent prognosis, and prolonged maintenance treatment may be unnecessary.

Thalassemia is an inherited blood disorder with worldwide distribution. Transfusion and chelation therapy have radically improved the prognosis of β-thalassemic patients in the developed world, but this has led to the development of new chronic cardiac complications like atrial fibrillation (AF). Prevalence of AF in patients with β-thalassemia is higher than in the general population, ranging from 2 to 33%. Studies are lacking, and the little evidence available comes from a small number of observational studies. The pathophysiology is not well understood but, while iron overload seems to be the principal mechanism, AF could develop even in the absence of iron deposition. Furthermore, the clinical presentation is mainly paroxysmal, and patients are highly symptomatic. The underlying disease, the pathophysiology, and the clinical presentation require a different management of AF in β-thalassemia than in the general population. Rhythm control should be preferred over rate control, and the most important antiarrhythmic therapy is represented by chelation drugs. Thromboembolic risk is high, but the available risk scores are not validated in β-thalassemia, and the choice of anticoagulation therapy should be considered early. The main purpose of this review is to summarize the actual knowledge about AF in β-thalassemia, with a specific focus on the clinical management of these complex patients.

Purpose: The present study aimed to compare the demographic, medical history, clinical features, and treatment management of paroxysmal supraventricular tachycardia (PSVT) in the emergency department of a teaching hospital in Riyadh, Saudi Arabia. A secondary purpose was to evaluate Adenosine response among numerous variables that might be used as predictors of the conversion. Methods: All PSVT cases presented to the Department of Emergency Medicine at King Khalid University Hospital, during the period from January 1, 2016, until December 31, 2016, were included in the study. Patients were assigned into two groups: adenosine sensitive (AS-group) and adenosine resistant (AR-group) according to adenosine conversion response. Results: A total of 38 patients were admitted during the study period. Fisher's exact test results showed that there were no signifi cant (P > 0.05) differences among the AS-group and AR-group in the demographics, past medical history and clinical features, and post-ablation condition, except for the previous usage of the other anti-arrhythmic drugs to convert the last PSVT in the AR-group. The first bolus of adenosine had higher sensitivity and specificity, compared to the second bolus. Further, the second bolus of adenosine was not specific for short-term treatment of PSVT. Conclusions: Differences in adenosine sensitivity among PSVT patients were independent of demographic, past medical history, and clinical features of PSVT patients. Thus, the difference in adenosine response among groups may be attributed to the heterozygosity in conducting pathways. The first bolus of adenosine had high sensitivity and specificity, compared to the second bolus, and their optimal levels were predictable by HR deceleration.

Supraventricular tachycardia (SVT) is a common medical condition. Diagnosis and treatment often occur simultaneously. To a great degree, long-term treatment options depend on the history of symptoms and the patient's desire, rather than on the specific type of SVT. [ABSTRACT FROM AUTHOR]

Objectives: To study the association of time intervals on adenosine therapy with the occurrence of refractory supraventricular tachycardia (SVT) in children.Methods: We reviewed 334 episodes of presumed SVT requiring adenosine in children (<18 years) who visited 4 academic hospital emergency departments (EDs) from July 2013 through June 2017. Refractory SVT was defined as an SVT episode persisting after 2 doses of adenosine. Clinical and electrocardiographic findings, and symptom-to-adenosine (symptom-to-ED plus ED-to-adenosine) time of refractory and responsive SVT episodes were compared. Multivariable logistic regression was performed to identify factors associated with the occurrence of refractory SVT.Results: Of 211 SVT episodes, 42 episodes of refractory SVT (19.9%) were noted (overall sinus conversion rate, 79.6%). The refractory episodes were associated with a higher frequency of known structural heart diseases (9.5% vs. 1.8%; P = 0.030) and a longer median ED-to-adenosine time (15.5 vs. 11.0 min; P = 0.018). The association of the ED-to-adenosine time with refractory SVT remained significant after adjustment (for increment of 1 min; aOR, 1.02; 95% CI, 1.007-1.04).Conclusions: Delayed adenosine therapy is associated with the occurrence of refractory SVT in children, supporting the need for prompt adenosine therapy. [ABSTRACT FROM AUTHOR]

Background: An association between paroxysmal supraventricular tachycardias (PSVT) and elevated cardiac troponin I (cTnI) has been reported in small studies, even in the absence of significant coronary artery or structural heart disease. We sought to explore the prognostic significance of elevated cTnI among patients presenting with PSVT.Methods: This is a retrospective single-center observational study conducted between January 2014 and Decemebr 2016. 165 patients (60% men, mean age 55 ± 17 year-old) with an acute episode of regular supraventricular tachyarrhythmia were admitted to the emergency department at Rambam Medical Center. 131 patients had at least one serum cTnI value measured. Of those, 57 had a positive result, defined as serum cTnI of more than 0.028 ng/dL.Results: Multivariate analysis showed that heart rate > 150 beats per minute (bpm) on admission (OR = 3.9; 95% CI 1.1.6-9.5; p < 0.003) and history of coronary artery disease (CAD) (OR = 3.4; 95% CI 1.2-10.1; p = 0.026) were the only independent predictors of cTnI elevation. After mean follow-up period of 23 ± 7 months, the combined primary outcome of death, coronary intervention (PCI) or myocardial infarction (MI) occurred in 7 patients (12.3%) out of 57 patients with positive cTnI and in zero patients with negative cTn (p = 0.002). Cox proportional hazard model showed that elevated cTnI on admission was an independent predictor of adverse outcomes only in patients with known coronary artery disease (CAD) (HR = 3.3, p = 0.05).Conclusion: Elevated cTnI among patients presenting with PSVT appears to have prognostic significance only in patients with history of CAD. In this patient group elevated cTnI is associated with increased risk of adverse cardiac outcomes. We therefore believe serum cTnI should be measured selectively, such as in patients with symptoms of ischemic chest pain and a high pretest likelihood of having CAD. [ABSTRACT FROM AUTHOR]

Background: Atrioventricular nodal reentrant tachycardia (AVNRT) is treatable by catheter ablation. Advances in mapping‐system technology permit fluoroless workflow during ablations. As national practice trends toward fluoroless approaches, easily obtained, reproducible methods of slow‐pathway identification, and ablation become increasingly important. We present a novel method of slow‐pathway identification and initial ablation results from this method. Methods and Results: We examined AVNRT ablations performed at our institution over a 12‐month period. In these cases, the site of the slow pathway was predicted by latest activation in the inferior triangle of Koch during sinus rhythm. Ablation was performed in this region. Proximity of the predicted site to the successful ablation location, complication rates, and patient outcomes were recorded. Junctional rhythm was seen in 40/41 ablations (98%) at the predicted site (mean, 1.3 lesions and median, 1 lesion per case). One lesion was defined as 5 mm of ablation. The initial ablation was successful in 39/41 cases (95%); in two cases, greater or equal to 2 echo beats were detected after the initial ablation, necessitating further lesion expansion. In 8/41 cases (20%), greater than one lesion was placed during initial ablation before attempted reinduction. Complications included one transient heart block and one transient PR prolongation. During follow‐up (median, day 51), one patient had lower‐extremity deep‐vein thrombosis and pulmonary embolus, and one had a lower‐extremity superficial venous thrombosis. There was one tachycardia recurrence, which prompted a redo ablation. Conclusions: Mapping‐system detection of late‐activation, low‐amplitude voltage during sinus rhythm provides an objective, and fluoroless means of identifying the slow pathway in typical AVNRT. [ABSTRACT FROM AUTHOR]

Supraventricular arrhythmias are frequent, and symptomatic patients often need medical therapy or catheter ablation. The recently published 2019 European Society of Cardiology (ESC) Guidelines for the management of patients with supraventricular tachycardia (SVT) give a comprehensive overview of current developments in the field and provides recommendations for the management of adults with SVT. In this paper, we briefly summarized major new recommendations and significant changes from the former ESC guideline published 16 years ago. [ABSTRACT FROM AUTHOR]

Tachyarrhythmias are seen both by children with structural heart disease and with anatomically normal heart. They can be divided into supraventriculars, which originate between the sinus and the atrioventricular node, and ventricular arrhythmias whose focus is situated below the level of the atrioventricular node. Most often supraventricular tachycardia is characterized by narrow QRS-complexes, with the exception of cases with aberrant conduction, while the hallmark of ventricular tachycardia is wide and deformed QRS-complexes. Adenosine is the drug of choice for termination of tachycardia with participation of the atrioventricular node. By the remaining arrhythmias the drug facilitates the diagnosis by delaying the conduction through the atrioventricular node. Amiodarone is effective by both supraventricular and ventricular arrhythmias. Definitive treatment of most arrhythmias can be achieved through electrophysiology study with radiofrequency ablation. [ABSTRACT FROM AUTHOR]

Differential diagnosis of supraventricular tachycardia (SVT) and ventricular tachycardia (VT) is of paramount importance for appropriate patient management. Several diagnostic algorithms for discrimination of VT and SVT based on surface electrocardiogram (ECG) analysis have been proposed. Following established diagnosis of VT, a specific origination tachycardia site can be supposed according to QRS complex characteristics. This review aims to cover comprehensive and comparative description of the main VT diagnostic algorithms and to present ECG characteristics which permit to suggest the most common VT origination sites. [ABSTRACT FROM AUTHOR]

Patients with supraventricular tachycardia commonly present to the ED. There is a lack of consensus regarding assessment of these patients. Our aim was to determine the utility of troponin and four other investigations (full blood examination, electrolyte levels, thyroid function tests and chest X‐rays) commonly requested for these patients. MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials (January 1992–March 2017) were searched for randomised controlled trials and observational studies (of sample size greater than 10). Our search strategy yielded no randomised controlled trials and seven observational studies with significant statistical heterogeneity among selected studies (I2 87.3%, P < 0.001). Included studies investigated a total of 1155 patients. All studies reported on the utility of troponin testing in this patient population. The pooled proportion of patients investigated with troponin was 0.66 (95% confidence interval 0.44–0.88). The pooled proportion of positive troponin tests was 0.32 (95% confidence interval 0.23–0.41). Only one study reported on the utility of the remaining four investigations with abnormal results as follows: thyroid stimulating hormone 14%, haemoglobin 6%, white cell count 19% and chest X‐ray 22%. Investigations are commonly requested for patients presenting with supraventricular tachycardia. Troponin testing is commonly performed with a high proportion of positive findings although these results did not appear to be associated with major adverse cardiac events. Heterogeneity among studies and low levels of evidence precluded conclusions on full blood examinations, electrolyte levels, thyroid testing and utility of chest X‐rays in this patient population. [ABSTRACT FROM AUTHOR]