Form Of Supraventricular Tachycardia Research Articles

Clinical Decision Support Requirements for Ventricular Tachycardia Diagnosis Within the Frameworks of Knowledge and Practice: Survey Study.

Ventricular tachycardia (VT) diagnosis is challenging due to the similarity between VT and some forms of supraventricular tachycardia, complexity of clinical manifestations, heterogeneity of underlying diseases, and potential for life-threatening hemodynamic instability. Clinical decision support systems (CDSSs) have emerged as promising tools to augment the diagnostic capabilities of cardiologists. However, a requirements analysis is acknowledged to be vital for the success of a CDSS, especially for complex clinical tasks such as VT diagnosis. The aims of this study were to analyze the requirements for a VT diagnosis CDSS within the frameworks of knowledge and practice and to determine the clinical decision support (CDS) needs. Our multidisciplinary team first conducted semistructured interviews with seven cardiologists related to the clinical challenges of VT and expected decision support. A questionnaire was designed by the multidisciplinary team based on the results of interviews. The questionnaire was divided into four sections: demographic information, knowledge assessment, practice assessment, and CDS needs. The practice section consisted of two simulated cases for a total score of 10 marks. Online questionnaires were disseminated to registered cardiologists across China from December 2022 to February 2023. The scores for the practice section were summarized as continuous variables, using the mean, median, and range. The knowledge and CDS needs sections were assessed using a 4-point Likert scale without a neutral option. Kruskal-Wallis tests were performed to investigate the relationship between scores and practice years or specialty. Of the 687 cardiologists who completed the questionnaire, 567 responses were eligible for further analysis. The results of the knowledge assessment showed that 383 cardiologists (68%) lacked knowledge in diagnostic evaluation. The overall average score of the practice assessment was 6.11 (SD 0.55); the etiological diagnosis section had the highest overall scores (mean 6.74, SD 1.75), whereas the diagnostic evaluation section had the lowest scores (mean 5.78, SD 1.19). A majority of cardiologists (344/567, 60.7%) reported the need for a CDSS. There was a significant difference in practice competency scores between general cardiologists and arrhythmia specialists (P=.02). There was a notable deficiency in the knowledge and practice of VT among Chinese cardiologists. Specific knowledge and practice support requirements were identified, which provide a foundation for further development and optimization of a CDSS. Moreover, it is important to consider clinicians' specialization levels and years of practice for effective and personalized support.

Arrhythmias Occurring in Children during HEMS Intervention: A Retrospective Cohort Study.

Arrhythmias in patients during medical transport remain a challenge for medical personnel. Helicopter emergency medical service (HEMS) crews, as the only medical rescue teams in Poland to conduct rescue flights, keep detailed documentation of monitoring vital functions over short time intervals during the flight. The aim of this study was to determine the characteristics of cardiac arrhythmia in pediatric patients (up to 12 years of age) transported by HEMS operatives, considering life-threatening rhythms and those that occur during out-of-hospital cardiac arrest (OHCA). The analysis of HEMS medical documentation covered 90345 missions carried out from 2011 to 2020. Among all activations, 820 cases of arrhythmias in pediatric patients up to 12 years of age were extracted. Missions for males accounted for 60% of all activations (n = 492), while flights for females accounted for 40% (n = 328). A statistically significant relationship between the number of HEMS flights and the season was demonstrated (p = 0.015). During the study period, pediatric patients mostly experienced cardiac arrhythmias in the form of supraventricular tachycardia (sVT) (n = 504). Asystole (n = 178) and pulseless electrical activity (PEA) (n = 52) ranked second and third in terms of occurrence, respectively. A statistically significant relationship between the type of heart rhythm disorder and age was demonstrated (p < 0.05). Heart rhythm disorders most often affected children between 0 and 3 years of age. As the patient's age increased, the incidence of arrhythmias decreased. Among pediatric patients, supraventricular tachycardia proved to be the predominant arrhythmia during the study period.

An unusual co-occurrence of lown-ganong-levine syndrome with neonatal focal lipomatous hypertrophy of interatrial septum with patent foramen ovale

We report an extremely rare co-occurrence of focal lipomatous hypertrophy of the interatrial septum (LHIS) with patent foramen ovale (PFO) in a neonate and electrocardiogram evidence of Lown-Ganong-Levine syndrome (LGL). Although atrial arrythmias in the form of supraventricular tachycardia like atrial premature contractions, atrial fibrillation, and atrioventricular block have been described in lipomatous hypertrophy interatrial septum, co-occurrence of LGL syndrome with LHIS has not been described in literature so far. Baby presented in the cardiology outpatient department for presurgical cardiological evaluation of congenital hydrocephalus. Typically, LHIS spares fossa ovalis and affects both side of the interatrial septum making interatrial septum dumbbell shaped. There is even no literature description of focal hypertrophy of interatrial septum in early infancy and child hood including neonatal period. Our case is a unique illustration of a rare co-occurrence of LGL syndrome in focal lipomatous hypertrophy of interatrial septum in a neonate with PFO.

Importance of the Activation Sequence of the His or Right Bundle for Diagnosis of Complex Tachycardia Circuits.

In this review, we emphasize the unique value of recording the activation sequence of the His bundle or right bundle branch (RB) for diagnoses of various supraventricular and fascicular tachycardias. A close analysis of the His to RB (H-RB) activation sequence can help differentiate various forms of supraventricular tachycardias, namely atrioventricular nodal reentry tachycardia from concealed nodofascicular tachycardia, a common clinical dilemma. Furthermore, bundle branch reentry tachycardia and fascicular tachycardias often are included in the differential diagnosis of supraventricular tachycardia with aberrancy, and the use of this technique can help the operator make the distinction between supraventricular tachycardias and these other forms of ventricular tachycardias using the His-Purkinje system. We show that this technique is enhanced by the use of multipolar catheters placed to span the proximal His to RB position to record the activation sequence between proximal His potential to the distal RB potential. This allows the operator to fully analyze the activation sequence in sinus rhythm as compared to that during tachycardia and may help target ablation of these arrhythmias. We argue that 3 patterns of H-RB activation are commonly identified-the anterograde H-RB pattern, the retrograde H-RB (right bundle to His bundle) pattern, and the chevron H-RB pattern (simultaneous proximal His and proximal RB activation)-and specific arrhythmias tend to be associated with specific H-RB activation sequences. We show that being able to record and categorize this H-RB relationship can be instrumental to the operator, along with standard pacing maneuvers, to make an arrhythmia diagnosis in complex tachycardia circuits. We highlight the importance of H-RB activation patterns in these complex tachycardias by means of case illustrations from our groups as well as from prior reports.

Assessing and Managing Asymptomatic Ventricular Preexcitation in the Young Athlete

Assessing and Managing Asymptomatic Ventricular Preexcitation in the Young Athlete

Long term prognosis in patients with pulmonary hypertension undergoing catheter ablation for supraventricular tachycardia

Various forms of supraventricular tachycardia (SVT) occur in patients with severe pulmonary hypertension (PH). Despite the high efficacy of radiofrequency catheter ablation (RFCA) for SVT, insufficient data exist regarding patients with PH. Thirty SVTs in 23 PH patients (age 47 [35–60] years; mean pulmonary artery pressure 44 [32–50] mmHg) were analyzed. Procedural success rate, short- and long-term clinical outcomes, were evaluated during a median follow-up of 5.1 years. Single-procedure success rate was 83%; 94% (17/18) in typical atrial flutter, 73% (8/11) in atrial tachycardia (AT), and 100% (1/1) in atrioventricular nodal reentrant tachycardia. Antiarrhythmic drugs, serum brain natriuretic peptide levels and number of hospitalizations significantly decreased after RFCA than that before (p = 0.002, 0.04, and 0.002, respectively). Four patients had several procedures. After last RFCA, 12 patients had SVT and 8 patients died. Kaplan–Meier curves showed that patients with SVT after the last RFCA had a lower survival rate compared to those without (p = 0.0297). Multivariate analysis identified any SVT after the last RFCA as significant risk factor of mortality (hazard ratio: 9.31; p = 0.016). RFCA for SVT in patients with PH is feasible and effective in the short-term, but SVT is common during long-term follow-up and associated with lower survival.

Arrhythmic risk during pregnancy in patients with congenital heart disease.

Arrhythmias play asignificant role in the morbidity and mortality of patients with adult congenital heart disease (CHD). Pregnancy-associated physiological changes in hormonal status, hemodynamics, and myocardial structure further enhance arrhythmic risk in CHD patients, leading to increased adverse maternal and foetal events and making arrhythmias one of the most common complications during pregnancy. Nearly all CHD patients are affected by asymptomatic rhythm disturbances during the ante-, peri-, or post-partum periods, and almost one tenth of patients develop sustained, symptomatic arrhythmias requiring treatment. The majority of arrhythmias originate from the atrium, mostly in the form of supraventricular tachycardia or atrial fibrillation. Patients with CHD often tolerate these even more poorly during pregnancy than before pregnancy. Sustained ventricular tachycardia or ventricular fibrillation are rare, but potentially life-threatening for mother and foetus. Risk stratification models developed specifically for arrhythmias during pregnancy in CHD patients are lacking, but direct or indirect signs of heart failure, previous history of arrhythmia, and complex CHD may be associated with higher arrhythmic risk in these patients. Rigorous individual assessment before, and careful monitoring during pregnancy in amultidisciplinary team is crucial to ensure the best possible pregnancy outcome for patients with CHD.

Essentials of Paroxysmal Supraventricular Tachycardia for the Pediatrician.

Paroxysmal supraventricular tachycardia (SVT) is the most common clinical arrhythmia in young patients. With an estimated prevalence of roughly 1 in 500 children, a pediatrician may knowingly or unknowingly see several patients who are affected each year. SVT symptoms can sometimes be vague or conflated with common pediatric complaints. Different forms of SVT are predominant at different ages, sometimes complicating timely recognition and referral. Differing pathophysiology and age distribution impact risk of complications such as heart failure, or rarely, sudden death. Treatment choices continue to evolve as new medications, monitoring devices, and ablation technologies continue to mature. This review focuses on the most common types of paroxysmal SVT: atrioventricular nodal reentrant tachycardia, atrioventricular reciprocating tachycardia, and Wolff-Parkinson White syndrome. Atrial arrhythmia mechanisms are also briefly outlined. It is meant to provide practical guidelines for the diagnosis and management of patients with SVT from infancy through adolescence. [Pediatr Ann. 2021;50(3):e113-e120.].

ОСОБЕННОСТИ НАРУШЕНИЙ СЕРДЕЧНОЙ ДЕЯТЕЛЬНОСТИ У ДЕТЕЙ ШКОЛЬНОГО ВОЗРАСТА, ПЕРЕНЕСШИХ СТРЕСС ВОЕННЫХ ДЕЙСТВИЙ

Влияние сильнейшего стрессового фактора на состояние здоровья детей, находившихся в эпицентре боевых действий в регионе Донбасса, в настоящее время является весьма актуальным и недостаточно изученным. Целью данного исследования явилась оценка психосоматического состояния здоровья детей 7-16 лет, в том числе деятельности сердечно-сосудистой системы. Обследовано 113 детей, проживающих в зоне военного конфликта. Проведено общее клиническое исследование состояния здоровья, включая психопатологические тесты и методики, адаптированные согласно возрасту, оценку физического развития (соматометрические и физиометрические данные), электрокардиографию, эхокардиографию и кардиоинтервалографию. В результате проведенного исследования выявлены психоэмоциональные нарушения (у 100%) и функциональные нарушения сердечно-сосудистой системы у 104 (92,04%) детей основной группы, с преобладанием жалоб на кардиалгии, сердцебиение, цефалгии, повышенную утомляемость, возбуждение, нарушения сна. Анализ электрокардиограмм выявил нарушения сердечного ритма в виде наджелудочковой тахикардии (34,51%), блокады правой ножки пучка Гиса (29,47%), атриовентрикулярной блокады и блокады левой ножки пучка Гиса (17,70%), миграции водителя ритма (9,73%), эктопических ритмов (6,19%), экстрасистолии (8,85%); изменения процессов деполяризации предсердий (51,33%) и реполяризации желудочков (64,60%); удлинение интервала QT (12,39%). Зарегистрировано снижение уровня физического развития в основной группе. У детей, длительно находившихся в стрессовой ситуации военного конфликта, значительно чаще встречалась соматическая патология, в частности патология нервной системы (89,38%) – расстройства вегетативной нервной системы и транзиторные тики; невротические, связанные со стрессом, и соматоформные расстройства – у 24,21% детей (реакция на тяжелый стресс и нарушения адаптации). У 58,41% детей выявлены хронические очаги инфекции носоглотки – хронические тонзиллиты; у 52,21% – заболевания органов пищеварения (дискинезия желчного пузыря и желчных путей, классифицируемые в МКБ-10 как «другие уточненные болезни желчного пузыря», а также функциональные расстройства кишечника в виде функциональных диарей); у 38,93% – нарушения костно-мышечной системы (деформирующие дорсопатии, а именно сколиозы, кифозы и лордозы); у 14,16% – болезни мочеполовой системы (циститы, острые тубулоинтерстициальные нефриты). Вегетативный гомеостаз характеризовался преобладанием симпатикотонического тонуса (48,67%) и гиперсимпатикотонической вегетативной реактивности. Длительное нахождение в зоне боевых действий значительно снизило адаптационные возможности детей, что привело к развитию дистресса.

Alternative Treatment Options for Atrioventricular-Nodal-Reentry Tachycardia: An Emergency Medicine Review

BackgroundAtrioventricular-nodal-reentry tachycardia (AVNRT) is a form of supraventricular tachycardia (SVT) that is relatively common in the emergency department (ED). It is rarely indicative of underlying electrical or structural pathology. ObjectiveThis review evaluates the literature and controversies concerning treatment of AVNRT in the ED. DiscussionFor treatment of narrow-complex tachycardia, Advanced Cardiovascular Life Support guidelines recommend the use of vagal maneuvers, followed by adenosine. Recent literature suggests that nondihydropyridine calcium channel blockers, such as verapamil and diltiazem, may be as effective as adenosine, without the negative short-term side effects. Multiple studies have demonstrated that although adenosine is rapid acting, there is no statistically significant difference in conversion rate between adenosine and calcium channel blockers. Both medications result in a conversion rate above 90%, but there are significantly more minor adverse effects, such as flushing or chest discomfort, with adenosine. Calcium channel blockers are a viable option for treatment for AVNRT, especially in refractory states. Beta-blockers have been evaluated but should not be used routinely due to lower efficacy. AVNRT is the most common tachydysrhythmia in pregnancy, and vagal maneuvers and adenosine are first line. Electrical cardioversion should be utilized for hemodynamically unstable patients. Most patients with AVNRT may be discharged with appropriate follow-up. ConclusionSeveral studies demonstrate that nondihydropyridine calcium channels (verapamil and diltiazem) are equally as efficacious as adenosine in converting AVNRT to sinus rhythm, without the negative (albeit short-lived) side effects. If given over 20 min, the risk for hypotension is low.

Human His-Purkinje System: Abnormalities of Conduction, Rhythm Disorders and Case Studies.

This review covers many of the arrhythmias and conduction abnormalities related to His-Purkinje System. These include junctional premature complexes, junctional and fascicular tachycardias, bundle branch reentry (BBR), and the role of apparent conduction in various forms of supraventricular tachycardias (SVT) with or without involvement of accessory pathways (AP).

IS THERE A DIFFERENCE IN TACHYCARDIA CYCLE LENGTH DURING SUPRAVENTRICULAR TACHYCARDIA IN CHILDREN WITH ATRIO-VENTRICULAR RECIPROCATING TACHYCARDIA AND ATRIO-VENTRICULAR NODAL RE-ENTRY TACHYCARDIA?

Atrio-ventricular reciprocating tachycardia (AVRT) and Atrio-ventricular nodal re-entry tachycardia (AVNRT) are the two most common forms of Supraventricular Tachycardia (SVT) in children. There is limited adult data suggesting the tachycardia cycle length (TCL) of AVRT is shorter than AVNRT, though

Cost-Effectiveness of Radiofrequency Ablation for Supraventricular Tachycardia in Guatemala: Patient Outcomes and Economic Analysis from a Low- to Middle-Income Country

BackgroundRadiofrequency ablation (RFA) is an established but expensive treatment alternative for many forms of supraventricular tachycardia (SVT). Currently, no studies exist on the cost-effectiveness of RFA compared with that of medical treatment (MT) in adult Latin American population. MethodsBetween 2007 and 2012, we identified 103 adults who underwent RFA for SVT in the National Unit of Cardiovascular Surgery (Unidad Nacional de Cirugía Cardiovascular [UNICAR]) in Guatemala. A decision tree was developed with all clinical outcome parameter estimates obtained from the Adult Electrophysiology Clinic. Cost data were obtained from UNICAR’s administration. A cost-effectiveness analysis that evaluated costs and quality-adjusted life-years to compare interventions in terms of their incremental cost-effectiveness ratios was conducted. ResultsThe first RFA had an 83% success rate, and a cumulative success rate of 94% was achieved with a second. The cost of the RFA procedure itself was $5411. RFA gained 1.46 quality-adjusted life-years and saved $7993 compared with MT for patients with SVT. This demonstrates that in Guatemala, RFA dominates MT in the management of SVT. Using assumptions based largely on the outcomes in UNICAR, we found that RFA is highly cost-effective. This is a consistent finding, even after varying assumptions about efficacy, complication rates, and quality of life. ConclusionsRFA dominates MT by improving quality of life and reducing expenditures when used to treat patients with severe symptoms of SVT in Guatemala. The robustness of these finding to variations in parameter assumptions suggests that these findings may hold in other similar settings.

Efficacy, Time, Cost and Radiation Exposure of Combined Limited Fluoroscopy with Non-fluoroscopic Three-dimensional Imaging in Paediatric Supraventricular Tachycardia Ablation – Best of Both Worlds

Objective: Catheter ablation for supraventricular tachycardias (SVTs) traditionally has utilised fluoroscopic imaging (FI). However, radiation concerns have recently contributed to the evolution of non-fluoroscopic three-dimensional imaging (3DI) systems. A few recent studies have advocated non-FI in lieu of FI. To date, there are only a few studies reporting use of limited FI with 3DI usage in children undergoing SVT ablations. This study evaluates time, efficacy, cost and safety of limited FI plus 3DI for SVT ablation in the young.Methods: Electrophysiology study (EPS) and ablation data for standard forms of SVT from October 2009 to June 2012 were reviewed. Patient radiation time, radiation dose area product (DAP), EPS time, anaesthesia duration and cost, and ablation success rates were evaluated.Results: A total of 81 patients (mean age 13.2 ± 3.4 years) underwent ablation. Type of SVT, gender, age, acute success, adverse events and recurrences were recorded post-ablation for over 2.5 years. Acute procedural success was 93.8 %. Of these, chronic sustained success was 85.5 %. As expected, limited FI plus 3DI was associated with some radiation exposure (2.47 ± 2.78 milliGray-m2) but less than historically associated with paediatric tachycardia ablations.Conclusion: A conscious awareness to use limited FI combined with 3DI is associated with excellent long-term success, lack of complications and marked decrease in radiation exposure. Although 3DI-only has some appeal, use of combined limited radiation is associated with some advantages overall. Potential adverse effects of limited radiation need to be weighed in when deciding which imaging or combination to use.

Initial experience with MediGuide in SVT: data from a multicenter registry

Background: Currently fluoroscopy-based catheter visualization is the standard modality in invasive electrophysiological procedures. Since May 2012 a new technology for non-fluoroscopic visualization of diagnostic and ablation catheters is available. The MediGuide®-system projects the catheter tips on prerecorded cine loops in a high time resolution; it has been introduced as real time 4D tracking. Methods: We report on MediGuide®-based SVT cases (AVRT; AVRT; WPW, EAT and typical atrial flutter) from 2 European centers. In all patients diagnostic and/or ablation catheters with a special sensor were used to perform the ablation procedures. All procedural data such as acute success, duration of the procedure, fluoroscopy time and –dose and patients' characteristics were analyzed. Procedure-related complications during the hospital stay were revealed. Results: A total of 23 patients were analyzed. Those patients were predominantly male (65%), aged 58±14 years and were ablated with the MediGuide® system for 6 AVNRT (26%), 4 AVRT/WPW (17%), 1 EAT (4%) and 13 typical atrial flutter (57%). The acute success rate was 100%. The median fluoroscopy time was 0,5±1,4min, the median fluoroscopy dose was 200±561cGy cm2. Mean procedure time was 74,6±25min. No complications during the hospital stay were recorded. ![Figure][1] Figure 1. MediGuide Conclusion: In different forms of supraventricular tachycardias the MediGuide® contributed to a dramatic reduction in irradiation exposure. At a median fluoroscopy time of 30s all SVT cases were effectively performed with no complications; the fluoroscopy burden can significantly be reduced not only for the patient but also for the nurses and the physicians. The overall procedure times are not prolonged due to the application of the MediGuide® system. [1]: pending:yes

Supraventricular Tachycardia

Supraventricular tachycardias (SVTs) comprise a group of arrhythmias for which the atria and/or atrioventricular (AV) node are integral to sustaining the rhythm. These arrhythmias typically have a benign natural history but account for a considerable proportion of patients presenting with symptoms including palpitations, shortness of breath, chest discomfort, dizziness, and, on occasion, syncope. They affect a broad range of patients, from young, otherwise healthy adults and children to elderly patients with multiple comorbidities. Although medical management with AV nodal blocking medications or antiarrhythmic medications is a reasonable first-line approach, catheter ablation is a definitive, most often curable option that has minimal risk and offers the chance of avoiding long-term medications. This chapter covers the epidemiology, diagnosis, and management of SVTs, which include atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), atrial tachycardia (AT), and others (atrial flutter, inappropriate sinus tachycardia, and junctional tachycardia). Atrial fibrillation, which is more prevalent than all other SVTs combined, are discussed elsewhere. Figures describe the differential diagnosis of tachycardia with narrow and wide QRS complexes, the relationship between the response to intravenous adenosine and the cause of tachycardia, the mechanism of tachycardia induction in patients with dual AV node conduction pathways, and the management of atrial flutter. Electrocardiograms illustrate features of various forms of SVT. This review contains 11 highly rendered figures (included 6 twelve-lead ECGs), 1 table, and 69 references.

Lone Atrial Fibrillation in the Young – Perhaps Not So “Lone”?

To determine if pediatric patients with a history of lone atrial fibrillation (AF) have other forms of supraventricular tachycardia (SVT) that may potentially trigger AF. A multicenter review of patients with lone AF who underwent electrophysiology (EP) study from 2006-2011 was performed. age ≤21 years, normal ventricular function, structurally normal heart, history of AF, and EP study and/or ablation performed. congenital heart disease or cardiomyopathy. Patient demographics, findings at EP study and follow-up data were recorded. Eighteen patients met inclusion criteria. The mean age was 17.9±2.2 years, weight was 82±21 kg, body mass index was 27±6, and 15 (83%) were males. Eleven (61%) were overweight or obese. Seven (39%) had inducible SVT during EP study: 5 atrioventricular nodal re-entry tachycardia (71%) and 2 concealed accessory pathways with inducible atrioventricular re-entry tachycardia (29%). All 7 patients with inducible SVT underwent radiofrequency ablation. There were no complications during EP study and/or ablation for all 18 patients. The mean follow-up was 1.7±1.5 years and there were no recurrences in the 7 patients who underwent ablation. There were 2 recurrences of AF in patients with no other form of SVT during EP study. Inducible SVT was found in 39% of pediatric patients undergoing EP study for lone AF. EP study should be considered for pediatric patients presenting with lone AF.

Maternal arrhythmias detected with electrocardiography during labour: Are they significant clinically?

SummaryThis study examines the maternal and fetal effects of arrhythmias detected by electrocardiographic (ECG) monitoring during labour in parturients at term, with no cardiovascular pathology. Pregnant cases were classified into three groups based on determined stages of labour and a standard 12-lead surface electrocardiogram and long-lead 2 rhythm strips were recorded during the labour. Cardiac arrhythmia of any kind was detected in 82.3% of patients in all stages of labour. Sinus tachycardia was the most commonly observed arrhythmia. Arrhythmias in the form of supraventricular tachycardia, T-wave inversion and ventricular extrasystole were also detected. The highest rate of arrhythmia was recorded for the active phase and 2nd phase of labour. Arrhythmias that are detected by ECG during or after the labour in patients with no cardiovascular pathology display a benign nature and do not create any clinical risk for the mother and the baby.

Focal Atrial Tachycardia I: Clinical Features, Diagnosis, Mechanisms, and Anatomic Location

Atrial tachycardia (AT) may be focal or macroreentrant. In this review we will concentrate on focal AT. The diagnosis of focal AT may be made from a standard electrocardiogram (ECG); however, in some cases differentiation from other forms of supraventricular tachycardia may be difficult. Focal AT may be due to several different mechanisms, including abnormal automaticity, triggered activity, and microreentry. Focal AT does not occur randomly throughout the atria but has a characteristic anatomic distribution. In this review, we particularly focus on the clinical features, diagnosis, mechanisms, and anatomic location of focal AT.

Successful catheter ablation of a slow AV-nodal pathway from the left posteroseptal region

We present the case of a 44 year old woman with recurrent episodes of supraventricular tachycardia due to AV-nodal reentry (AVNRT). She was refractory to conventional medical treatment and referred to our hospital with the view to catheter ablation of the slow AV-nodal pathway. AVNRT of the common type was easily induced performing stimulation from the high right atrium and proximal coronary sinus. Other forms of supraventricular tachycardia were definitely ruled out during further electrophysiologic study. Repetitive RF applications around the right posteroseptal region failed to cure the tachycardia which remained inducible with a typical jump in the AH interval. Extensive RF applications from posteroinferior to the midseptum including the area of the proximal coronary sinus and its os were ineffective as well.AVNRT was transiently but reproducibly eliminated while burns were applied to the high midseptum but AVNRT reoccured within 20 minutes. Finally after retrograde passage of the aortic valve with a 4 mm tip ablation catheter, RF was applied to the left postero to midseptal region. An accelerated junctional rhythm was immediately observed and AVNRT remained non-inducible from that time onwards. It is concluded that an atypical posterior extension of the AV node with predominant leftatrial course might be responsible for this unusual success of slow pathway elimination from left posteroseptal.