[Sick sinus node syndrome ¿Pacemaker or ablation? Case report]. / Síndrome del nodo sinusal enfermo ¿marcapaso o ablación? Reporte de caso.

The tachycardia-bradycardia syndrome is the most frequent form of presentation of Sick sinus node syndrome and is commonly characterized by episodes of paroxysmal atrial fibrillation followed by significant pauses, especially in older adult patients. Other frequently associated tachyarrhythmias are atrial tachycardia and atrial flutter. The association between orthodromic tachycardia and significant pauses in these patients is an unusual presentation. We present the case of an older adult with bradycardia-tachycardia syndrome and syncope, who presented with a hidden accessory pathway and who, after successful ablation of it, did not present syncope again.

Taquicardia supraventricular sostenida tras inducción anestésica inhalatoria con sevoflurano en paciente pediátrico / Persistent supraventricular tachycardia after volatile inhalational anaesthetic induction with sevoflurane in a pediatric patient

La inducción anestésica inhalatoria con sevoflurano es muy empleada en la población pediátrica. Si bien los efectos sistémicos más comunes son ampliamente conocidos, no se conocen todos los efectos secundarios de este fármaco. Presentamos el caso clínico de un varón de cuatro años que desarrolló un episodio de taquicardia supraventricular sostenida tras la inducción anestésica con sevoflurano, que no cedió hasta que no se retiró el fármaco y se sustituyó el mantenimiento anestésico por una perfusión continua de fármacos hipnóticos intravenosos (propofol y remifentanilo). Desconocemos el mecanismo exacto por el que este episodio ha tenido una relación causal tan clara con la administración de sevoflurano; las posibilidades diagnósticas serían la taquicardia por reentrada intranodal o la existencia de una vía accesoria. No hemos encontrado en la literatura un episodio de taquicardia supraventricular mantenida con una relación causal directa con la administración de sevoflurano como en el caso que presentamos.(AU)

Inhaled anaesthetic induction with sevoflurane is very common in the pediatric population. Sevoflurane systemic effects are widely known, while not all the side effects are known. We present a four year-old child who developed a persistent supraventricular tachycardia af-ter inhaled anaesthetic induction with sevoflurane. The arrhythmia did not end until sevoflurane was stopped and changed to an intravenous continuous perfusion ofhypnotic drugs (propofol and remiphentanyl). The exact mechanism for such a causal relationship with sevoflurane administration is unknown, and possible diagnoses include atrioventricular nodal reentry tachycardia (AVNRT) and the existence of an accessory pathway. An episode of persistent supraventricular tachycardia with a clear causal relationship with sevoflurane administration is not found in the literature.(AU)

Ventricular versus atrial side ablation for treatment of atrioventricular accessory pathways: a randomized controlled clinical trial.

BACKGROUND: The earliest atrial (A)/ventricular (V) activation potentials, or fused A/V potentials, are commonly used as ablation targets for atrioventricular (AV) accessory pathways (APs). However, these targets can be achieved in a relatively wide area of the heart around AV rings at both atrial and ventricular sides. The aim of this study is to analyze the height of intracardiac A and V waves and their correlation to find the most appropriate side for successful delivery of radiofrequency energy, atrial or ventricular edge. METHODS: Ninety patients diagnosed with orthodromic AV re-entrant tachycardia (AVRT) or Wolff-Parkinson-White syndrome were enrolled. Local atrial/ventricular (A/V) amplitude potentials with the earliest activation or fused AV potentials were measured. Patients were randomly assigned into two groups with a 2:1 ratio. In group 1, ablation was done at the site where A was greater than V. In group 2, V was greater than A. Primary endpoint was success at first attempt, achieving antegrade AP conduction block, AV block during right ventricle pacing, or AVRT termination with no AP conduction. RESULTS: Fifty-one patients (56.7%) were male. Thirty patients had an ablation at an atrial site (A > V) and 60 at a ventricular site (V > A). Ablation was more successful at the ventricular site (87% vs 100%, P = 0.011). All 30 patients in the atrial arm and 71% of the ventricular group underwent ablation via the antegrade method. CONCLUSIONS: Success of catheter ablation of APs is higher where V > A (ventricular site of AP), indicating the priority of the ventricular edge of the mitral ring for a better outcome.

Orthodromic Atrioventricular Tachycardia in Wolff-Parkinson-White Syndrome with Two Accessory Pathways Participation during the Same AVT

Case report of a 49-year-old patient with Wolff-Parkinson-White syndrome, very symptomatic, with apparent parahisian pathway who, during an electrophysiological study, presented orthodromic atrioventricular tachycardia, featuring two accessory pathways, retrogradely, the parahisian pathway and a hidden left posterolateral pathway, during the same tachycardia, alternating the retrograde pathway of tachycardia without interruption.

Transient complete heart block following catheter ablation of a left lateral accessory pathway.

A 16-year-old female with symptomatic Wolff-Parkinson-White (WPW) syndrome underwent catheter ablation of a left-sided lateral accessory pathway. The accessory pathway was eliminated with the first ablation lesion; however, the patient immediately developed complete heart block (CHB). At first, complete heart block was thought to be due to ablation of left atrial extension of the AV node, and pacemaker therapy was considered. However, careful ECG analysis revealed that the development of CHB was in fact due to bump injury to the AV node during transseptal catheterization. Conservative management allowed resolution of AV nodal conduction without need for a permanent pacemaker.

Accuracy of the Electrocardiogram in Localizing the Accessory Pathway in Patients with Wolff-Parkinson-White Pattern / Acurácia do Eletrocardiograma na Localização da Via Acessória em Pacientes com Padrão de Wolff-Parkinson-White

Abstract Background: There are currently several electrocardiographic algorithms to locate the accessory pathway (AP) in patients with Wolff-Parkinson-White (WPW) syndrome. Objective: To compare the ability of electrocardiographic algorithms in identifying the location of the AP in patients with WPW pattern referred for ablation. Methods: Observational, cross-sectional, retrospective study with 111 patients with WPW syndrome referred for AP ablation. The electrocardiogram (ECG) obtained prior to the ablation was analyzed by an experienced observer who consecutively applied seven algorithms to identify non-invasively the AP. We then compared the location estimated with this assessment with that obtained in the electrophysiological study and calculated the agreement rates. Results: Among the APs, 59 (53.15%) were distributed around the mitral annulus and the remaining 52 (46.85%) were located around the tricuspid annulus. The overall absolute accuracy of the algorithms evaluated varied between 27% and 47%, increasing to between 40% and 76% when we included adjacent locations. The absolute agreement rate by AP location was 2.00-52.20% for septal APs (n = 51), increasing to 5.90-90.20% when considering adjacent locations; 7.70-69.20% for right APs (n = 13), increasing to 42.90-100% when considering adjacent locations; and 21.70-54.50% for left APs (n = 47), increasing to 50-87% when considering adjacent locations. Conclusion: The agreement rates observed for the analyzed scores indicated a low discriminative ability of the ECG in locating the AP in patients with WPW.

Resumo Fundamento: Existem atualmente vários algoritmos eletrocardiográficos para localizar a via acessória (VA) em pacientes com síndrome de Wolff-Parkinson-White (WPW). Objetivo: Comparar a capacidade discriminativa dos algoritmos eletrocardiográficos na localização da VA no padrão de WPW em pacientes encaminhados para ablação. Métodos: Estudo observacional, transversal e retrospectivo, incluindo 111 pacientes com síndrome de WPW encaminhados para ablação da VA. O eletrocardiograma (ECG) prévio à ablação foi analisado por um observador experiente que aplicou consecutivamente sete algoritmos para identificar a VA de forma não invasiva. A localização estimada com esta avaliação foi comparada à obtida no estudo eletrofisiológico e as taxas de acerto foram calculadas. Resultados: Entre as VAs, 59 (53,15%) estavam distribuídas ao redor do anel mitral e as restantes 52 (46,85%) em torno do anel tricúspide. O acerto global absoluto dos algoritmos em estudo variou entre 27% e 47%, aumentando para 40% a 76% quando incluímos localizações adjacentes. O acerto absoluto em função da localização da VA foi o seguinte: para as VAs septais (n = 51) variou entre 2% e 52,20% (5,90% e 90,20% incluindo localizações adjacentes), para as VAs direitas (n = 13) variou entre 7,70% e 69,20% (42,90% e 100%, incluindo localizações adjacentes), para as VAs esquerdas (n = 47) variou entre 21,70% e 54,50% (50% a 87%, incluindo as localizações adjacentes). Conclusões: Os índices de acerto observados para os escores analisados indicaram uma reduzida capacidade discriminativa do ECG na localização da VA em pacientes com WPW.

Risk Stratification for Arrhythmic Events in Patients With Asymptomatic Pre-Excitation: A Systematic Review for the 2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

OBJECTIVE: To review the literature systematically to determine whether noninvasive or invasive risk stratification, such as with an electrophysiological study of patients with asymptomatic pre-excitation, reduces the risk of arrhythmic events and improves patient outcomes. METHODS: PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (all January 1, 1970, through August 31, 2014) were searched for randomized controlled trials and cohort studies examining noninvasive or invasive risk stratification in patients with asymptomatic pre-excitation. Studies were rejected for low-quality design or the lack of an outcome, population, intervention, or comparator of interest or if they were written in a language other than English. RESULTS: Of 778 citations found, 9 studies met all the eligibility criteria and were included in this paper. Of the 9 studies, 1 had a dual design-a randomized controlled trial of ablation versus no ablation in 76 patients and an uncontrolled prospective cohort of 148 additional patients-and 8 were uncontrolled prospective cohort studies (n=1594). In studies reporting a mean age, the range was 32 to 50 years, and in studies reporting a median age, the range was 19 to 36 years. The majority of patients were male (range, 50% to 74%), and <10% had structural heart disease. In the randomized controlled trial component of the dual-design study, the 5-year Kaplan-Meier estimates of the incidence of arrhythmic events were 7% among patients who underwent ablation and 77% among patients who did not undergo ablation (relative risk reduction: 0.08; 95% confidence interval: 0.02 to 0.33; P<0.001). In the observational cohorts of asymptomatic patients who did not undergo catheter ablation (n=883, with follow-up ranging from 8 to 96 months), regular supraventricular tachycardia or benign atrial fibrillation (shortest RR interval >250 ms) developed in 0% to 16%, malignant atrial fibrillation (shortest RR interval ≤250 ms) in 0% to 9%, and ventricular fibrillation in 0% to 2%, most of whom were children in the last case. CONCLUSIONS: The existing evidence suggests risk stratification with an electrophysiological study of patients with asymptomatic pre-excitation may be beneficial, along with consideration of accessory-pathway ablation in those deemed to be at high risk of future arrhythmias. Given the limitations of the existing data, well-designed and well-conducted studies are needed.

Risk stratification for arrhythmic events in patients with asymptomatic pre-excitation: A systematic review for the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

OBJECTIVE: To review the literature systematically to determine whether noninvasive or invasive risk stratification, such as with an electrophysiological study of patients with asymptomatic pre-excitation, reduces the risk of arrhythmic events and improves patient outcomes. METHODS: PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (all January 1, 1970, through August 31, 2014) were searched for randomized controlled trials and cohort studies examining noninvasive or invasive risk stratification in patients with asymptomatic pre-excitation. Studies were rejected for low-quality design or the lack of an outcome, population, intervention, or comparator of interest or if they were written in a language other than English. RESULTS: Of 778 citations found, 9 studies met all the eligibility criteria and were included in this paper. Of the 9 studies, 1 had a dual design-a randomized controlled trial of ablation versus no ablation in 76 patients and an uncontrolled prospective cohort of 148 additional patients-and 8 were uncontrolled prospective cohort studies (n=1,594). In studies reporting a mean age, the range was 32 to 50 years, and in studies reporting a median age, the range was 19 to 36 years. The majority of patients were male (range, 50% to 74%), and <10% had structural heart disease. In the randomized controlled trial component of the dual-design study, the 5-year Kaplan-Meier estimates of the incidence of arrhythmic events were 7% among patients who underwent ablation and 77% among patients who did not undergo ablation (relative risk reduction: 0.08; 95% confidence interval: 0.02 to 0.33; p<0.001). In the observational cohorts of asymptomatic patients who did not undergo catheter ablation (n=883, with follow-up ranging from 8 to 96 months), regular supraventricular tachycardia or benign atrial fibrillation (shortest RR interval >250 ms) developed in 0% to 16%, malignant atrial fibrillation (shortest RR interval ≤250 ms) in 0% to 9%, and ventricular fibrillation in 0% to 2%, most of whom were children in the last case. CONCLUSIONS: The existing evidence suggests risk stratification with an electrophysiological study of patients with asymptomatic pre-excitation may be beneficial, along with consideration of accessory-pathway ablation in those deemed to be at high risk of future arrhythmias. Given the limitations of the existing data, well-designed and well-conducted studies are needed.

Risk Stratification for Arrhythmic Events in Patients With Asymptomatic Pre-Excitation: A Systematic Review for the 2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

OBJECTIVE: To review the literature systematically to determine whether noninvasive or invasive risk stratification, such as with an electrophysiological study of patients with asymptomatic pre-excitation, reduces the risk of arrhythmic events and improves patient outcomes. METHODS: PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (all January 1, 1970, through August 31, 2014) were searched for randomized controlled trials and cohort studies examining noninvasive or invasive risk stratification in patients with asymptomatic pre-excitation. Studies were rejected for low-quality design or the lack of an outcome, population, intervention, or comparator of interest or if they were written in a language other than English. RESULTS: Of 778 citations found, 9 studies met all the eligibility criteria and were included in this paper. Of the 9 studies, 1 had a dual design-a randomized controlled trial of ablation versus no ablation in 76 patients and an uncontrolled prospective cohort of 148 additional patients-and 8 were uncontrolled prospective cohort studies (n=1,594). In studies reporting a mean age, the range was 32 to 50 years, and in studies reporting a median age, the range was 19 to 36 years. The majority of patients were male (range, 50% to 74%), and <10% had structural heart disease. In the randomized controlled trial component of the dual-design study, the 5-year Kaplan-Meier estimates of the incidence of arrhythmic events were 7% among patients who underwent ablation and 77% among patients who did not undergo ablation (relative risk reduction: 0.08; 95% confidence interval: 0.02 to 0.33; p<0.001). In the observational cohorts of asymptomatic patients who did not undergo catheter ablation (n=883, with follow-up ranging from 8 to 96 months), regular supraventricular tachycardia or benign atrial fibrillation (shortest RR interval >250 ms) developed in 0% to 16%, malignant atrial fibrillation (shortest RR interval ≤250 ms) in 0% to 9%, and ventricular fibrillation in 0% to 2%, most of whom were children in the last case. CONCLUSIONS: The existing evidence suggests risk stratification with an electrophysiological study of patients with asymptomatic pre-excitation may be beneficial, along with consideration of accessory-pathway ablation in those deemed to be at high risk of future arrhythmias. Given the limitations of the existing data, well-designed and well-conducted studies are needed.

Intermittent, subtle change of ST segment in narrow QRS regular tachycardia

No abstract available.