Unilateral atrial ectopic rhythm in a golden retriever

Background: Atrial ectopic rhythm is a type of supraventricular arrhythmia, originating in two distinct points in the atrialregion. In the electrocardiographic (ECG) tracing, it is represented by independent depolarizations of sinus P waves andectopic P waves. The occurrence of this disorder is rare, and the diagnosis criteria are the presence of the described waveswithin the basal rhythm. In humans, there have been reports related to severe heart failure with an unfavorable prognosis.The present report aimed to describe the clinical case of a dog with unilateral atrial ectopic rhythm without any underlying cardiac disorder.Case: A 8-year-old male golden retriever was brought to a veterinary clinic for a preoperative evaluation for lipoma removalin the right forelimb. On clinical examination, the owner stated that the patient was active, with no signs of easy fatigueor cough. The canine displayed normophagy, normodipsia, normoquezia, and normouria. On physical examination, hedemonstrated a lymphatic temperament with tachypnea. The temperature and capillary filling time were within the normalrange, with a normokinetic pulse. Cardiac auscultation revealed a mild grade I/VI murmur in mitral focus and an 80-bpmheart rate. Respiratory auscultation revealed the presence of harshy lung sounds. The cough reflex was positive; the Piparotetest, negative. The blood test showed no noticeable changes in blood count and serum biochemistry. Systemic systolicblood pressure was 120 mmHg. On radiographic examination, no evidence of heart or lung abnormalities were identified.After the clinical evaluation, an ECG examination was performed; a unilateral atrial ectopic rhythm was observed withdifferent frequencies between atrial and ventricular rhythm and with P (164°) and P waves (80°). On echocardiographic...(AU)

Unilateral atrial ectopic rhythm in a golden retriever

Background: Atrial ectopic rhythm is a type of supraventricular arrhythmia, originating in two distinct points in the atrialregion. In the electrocardiographic (ECG) tracing, it is represented by independent depolarizations of sinus P waves andectopic P waves. The occurrence of this disorder is rare, and the diagnosis criteria are the presence of the described waveswithin the basal rhythm. In humans, there have been reports related to severe heart failure with an unfavorable prognosis.The present report aimed to describe the clinical case of a dog with unilateral atrial ectopic rhythm without any underlying cardiac disorder.Case: A 8-year-old male golden retriever was brought to a veterinary clinic for a preoperative evaluation for lipoma removalin the right forelimb. On clinical examination, the owner stated that the patient was active, with no signs of easy fatigueor cough. The canine displayed normophagy, normodipsia, normoquezia, and normouria. On physical examination, hedemonstrated a lymphatic temperament with tachypnea. The temperature and capillary filling time were within the normalrange, with a normokinetic pulse. Cardiac auscultation revealed a mild grade I/VI murmur in mitral focus and an 80-bpmheart rate. Respiratory auscultation revealed the presence of harshy lung sounds. The cough reflex was positive; the Piparotetest, negative. The blood test showed no noticeable changes in blood count and serum biochemistry. Systemic systolicblood pressure was 120 mmHg. On radiographic examination, no evidence of heart or lung abnormalities were identified.After the clinical evaluation, an ECG examination was performed; a unilateral atrial ectopic rhythm was observed withdifferent frequencies between atrial and ventricular rhythm and with P (164°) and P waves (80°). On echocardiographic...

Ablação de ectopias juncionais frequentes com reversão de taquicardiomiopatia / Ablation of frequent junctional ectopias with reversal of tachycardiomyopathy

INTRODUÇÃO: Ectopias juncionais (EJs) possuem origem nas fibras de Purkinje da junção atrioventricular (AV), ocasionadas por hiperautomatismo ou atividade deflagrada e podem evoluir com taquicardiomiopatia. A ablação é uma alternativa de tratamento e envolve cautela pelo risco de bloqueio AV. DESCRIÇÃO: Mulher de 45 anos com queixas de palpitações e cansaço, extrassístoles supraventriculares de alta densidade no Holter (39%), disfunção ventricular ao ecocardiograma (FEVE 47%), refratária ao uso de amiodarona 200mg/dia e metoprolol 50mg/dia foi encaminhada para ablação. O estudo eletrofisiológico demonstrou intervalos básicos normais (PR:190ms; PA:34ms; AH:102ms; HV:54ms; QRS:72ms; QT:360ms). Durante a monitorização, a paciente apresentava ritmo sinusal com ectopias juncionais de complexos QRS estreito (72ms) e QRS largo (120ms) com padrão de bloqueio do ramo esquerdo. Realizou-se o mapeamento do potencial de Purkinje sendo observada maior precocidade (56ms) na porção distal da junção AV (local com eletrograma atrial de baixa amplitude). Aplicações de radiofrequência (10W a 20W, 60°C), com cateter terapêutico de 4 mm, eliminaram as ectopias após 2 segundos. Durante as aplicações, ocorreu bloqueio da condução pelo ramo direito e alargamento do intervalo PR. Os intervalos básicos ao término do procedimento foram PR:250ms; PA:40ms; AH:150ms; HV:60ms; QRS:130ms; QT:408ms). O Holter previamente à alta hospitalar demonstrou ectopias juncionais de baixa densidade (3%) e períodos de bloqueio atrioventricular de segundo grau tipo I. Após 30 dias, a paciente permaneceu sem medicações, assintomática, com extrassístoles infrequentes ao exame físico, ritmo sinusal com bloqueio de ramo direito, teste ergométrico com frequência máxima atingida de 162bpm e evoluiu com normalização da função ventricular. CONCLUSÃO: A ablação por radiofrequência de EJs refratárias é factível e possibilitou a normalização da função ventricular no caso apresentado. Deve-se avaliar a relação risco/benefício pela possibilidade de bloqueio AV total.

Ectopias atriais e associação com fibrilação atrial / Atrial ectopes and atrial fibrillation association

Instabilidade elétrica atrial é um termo recentemente incorporado na prática médica para descrever o amplo espectro de arritmias atriais que se sobrepõem. Essa relação já era intuitiva entre flutter atrial e fibrilação atrial (que deu berço ao anteriormente chamado "fibrilo-flutter"), e, mais recentemente, associou taquicardias atriais e fibrilação atrial. Essa relação é de suma importância, posto que o diagnóstico de fibrilação atrial implica estratégias para prevenção de eventos embólicos. Com novos métodos de rastreio, o diagnóstico de fibrilação atrial se mostrou mais frequente (monitorização prolongada, monitores implantáveis, telemetria de marcapassos). A presença de extrassistolia atrial e taquicardia atrial se torna um desafio: apesar da relação intuitiva de maior risco para fibrilação atrial e eventos cerebrovasculares, a evidência científica para tal se tornou mais robusta recentemente. Este artigo tem a intenção de agregar a evidência de melhor qualidade disponível para facilitar a seleção da estratégia adequada ante um paciente portador de taquicardia e extrassistolia atrial e avaliar adequadamente seu risco

Atrial electrical instability is a recently incorporated term in medical practice to describe the broad spectrum of overlapping atrial arrhythmias. This relationship was already intuitive between atrial flutter and atrial fibrillation (which gave birth to the so-called "fibril-flutter"), and has more recently been related to atrial tachycardias and atrial fibrillation. This relationship is extremely important, since the diagnosis of atrial fibrillation implies in strategies to prevent embolic events. With new screening methods, the diagnosis of atrial fibrillation has become more frequent (prolonged monitoring, implantable monitors, pacemaker telemetry). The presence of atrial extrasystoles and atrial tachycardia is a challenge: despite the intuitive relationship of higher risk for atrial fibrillation and cerebrovascular events, the scientific evidence became more robust recently. This article intends to aggregate the best quality evidence available to facilitate the choice of an appropriate strategy for a patient with tachycardia and atrial extrasystoles and to adequately assess their risk

Taquiarritmias Atriais: Diagnóstico e Tratamento / Atrial Tachyarrhythmias: Diagnosis and Treatment

As taquiarritmias atriais representam um grupo heterogêneo de arritmias dentro das taquicardias supraventriculares, que apresentam como característica comum a ausência do nó atrioventricular como parte integrante do circuito destas arritmias. Dentre elas, destacam-se as taquicardias atriais, que podem ser focais ou macrorreentrantes. O eletrocardiograma é uma ferramenta importante nesta diferenciação, assim como o estudo eletrofisiológico, valendo-se de técnicas de mapeamento eletroanatômico (MEA), cada vez mais apuradas para este diagnóstico. As taquicardias atriais focais representam especial desafio diagnóstico e terapêutico. Padrões eletrocardiográficos, avaliação dos padrões da arritmia durante monitorização eletrocardiográfica prolongada, avaliação dos padrões de resposta a fármacos e avaliação da ativação atriale da resposta a manobras durante estudo eletrofisiológico constituem a base do seu diagnóstico. Com o desenvolvimento de novas técnicas e taxas de sucesso crescente, a ablação por radiofrequência tem se tornado, nos últimos anos, o tratamento de escolha para pacientes com taquicardia atrial focal sintomática, especialmente nos casos de taquicardia atrial incessante, pelo risco potencial de desenvolvimento de taquicardiomiopatia. Este artigo tem por objetivo realizar revisão da literatura quanto aos aspectos mais atuais no diagnóstico e tratamento das principais taquiarritmias atriais...

Atrial tachyarrhythmias are a heterogeneous group within the supraventricular tachycardia group that share in common the absence of the atrioventricular node as an integral componente of the arrhythmia circuit. Among them, special attention is given to atrial tachycardias (AT), which may present as focal or macroreentrant. The electrocardiogram (EKG) is an important tool in this differentiation, as is the electrophysiological study using techniques of electroanatomical mapping (EAM), both of which are becoming increasingly accurate in this diagnosis. The diagnosis and treatment of focal atrial tachycardias are challenging. The diagnosis is based on electrocardiographic patterns, evaluation of the patterns of arrhythmia during prolonged electrocardiographic monitoring, evaluation of the patterns of response to drugs, and evaluation of the atrial activation and the response to maneuvers during electrophysiological testing. With the development of new techniques, and the increasing success rates, radiofrequency ablation (RFA) has become the gold standard therapy in recent years for patients with symptomatic focal atrial tachycardia, particularly in cases of incessant atrial tachycardia, due to the potential risk for the development of tachycardia-induced cardiomyopathy.The objective of this article is to present a review of the literature, emphasizing the current aspects of diagnosis and therapy for atrial tachyarrhythmias...

Taquicardia auricular en el periodo neonatal. Presentación de un caso / Atrial Tachycardia in the neonatal period. A case presentation

Los trastornos del ritmo en la época neonatal son relativamente frecuentes y comprenden un espectro clínico variado, generalmente benigno, pero hay situaciones de gravedad, que debemos saber identificar y tratar. En la mayoría de los casos, en la actualidad, se cuenta con el diagnostico prenatal e incluso la posibilidad de iniciar tratamiento intraútero. Son más frecuentes en la población prematura y en general desaparecen en los primeros días de vida. Se muestra el caso de un recién nacido a término con buen peso al nacer que presenta un episodio de taquicardia auricular durante las primeras 24 horas de vida. Se describe el manejo del paciente y se realiza un breve comentario del tema (AU)

The rhythm´s disorders during neonatal period are relatively frequent and they include a varied clinical spectrum, generally benign, but there are gravity situations, which we must be able to identify and treat. In most cases, nowadays, we have prenatal diagnosis and even the possibility of initiating an intrauterine treatment. They are more frequent in the premature population and generally they disappear in the first days of life. It is shown a case of a term birth newborn with good birth weight who presents an episode of atrial tachycardia during the first 24 hours of life. It is described the patient´s management and it is done a brief comment of the topic (AU)

[Tachycardiomyopathy as a reversible cause of heart failure: report of one case]. / Taquicardiomiopatía, causa reversible de insuficiencia cardiaca: caso clínico.

Tachycardiomyopathy is a potentially reversible cause of heart failure. It can be induced by supraventricular or ventricular arrhythmias. When these are treated, systolic function improves or normalizes. We report a 20 year-old male with deterioration of left ventricular function and dilated cardiomyopathy secondary to an incessant atrial tachycardia that was treated with radiofrequency catheter ablation. After the procedure, the patient experienced a significant improvement of his ventricular function.

Taquicardiomiopatía, causa reversible de insuficiencia cardiaca: caso clínico / Tachycardiomyopathy as a reversible cause of heart failure: Report of one case

Tachycardiomyopathy is a potentially reversible cause of heart failure. It can be induced by supraventricular or ventricular arrhythmias. When these are treated, systolic function improves or normalizes. We report a 20year-old male with deterioration of left ventricular function and dilated cardiomyopathy secondary to an incessant atrial tachycardia that was treated with radiofrequency catheter ablation. After the procedure, the patient experienced a significant improvement of his ventricular function.

Distinct pharmacologic substrate in lidocaine-sensitive, repetitive atrial tachycardia.

Lidocaine-sensitive, repetitive atrial tachycardia is an uncommon arrhythmia. The electrophysiologic substrate is still unknown, and the pharmacologic responses have not been fully explored. The aim of this study was to investigate the effects of intravenous adenosine and verapamil in patients with lidocaine-sensitive atrial tachycardia. In 9 patients with repetitive uniform atrial tachycardia, the response to intravenous adenosine (12 mg), lidocaine (1 mg/kg body weight), and verapamil (10 mg) were sequentially investigated. Simultaneous 12-lead electrocardiogram (ECG) was recorded at baseline and continuously monitored thereafter. Tracings were obtained at regularly timed intervals right after the administration of each drug to evaluate changes in the arrhythmia characteristics. Repetitive atrial tachycardia was abolished by intravenous lidocaine in the 9 patients within the first 2 minutes after the end of injection. Adenosine suppressed the arrhythmia in 2 patients and shortened the runs of atrial ectopic activity in 1 patient, while verapamil was effective in 2 patients, 1 of them insensitive to adenosine and the other 1 sensitive to this agent. In 5 patients, the arrhythmia was abolished by radiofrequency ablation at different sites of the right atrium. Lidocaine-sensitive atrial tachycardia may eventually be also suppressed by adenosine and/or verapamil. This suggests that this enigmatic arrhythmia may be caused by different underlying electrophysiologic substrates and that at least in some cases, delayed afterdepolarizations seem to play a determining role.

Ablación con catéter de las taquicardias auriculares focales guiada por mapeo electroanatómico / Electroanatomic mapping and radiofrequency catheter ablation of focal atrial tachycardias

Focal atrial tachycardia is defined as supraventricular tachycardia originating from discrete sites from which activation spreads to both atrial. In most clinical series, atrial tachycardia account for about 5% of all supraventricular arrythmias. This tachycardia can occur in children or adults within and without structural heart disease. Three potential mechanisms are described for its origin: abnormal automaticity, triggered activity or microreentry. Catheter ablation has an important role in the management of focal atrial tachycardia and is now considered to be a first line therapy, can be improved with electroanatomical mapping system (CARTO) that allows reconstruction of the chamber geometry and allow visualization of the activation sequence; and can to improve the efficacy of catheter ablation.

Radiofrequency ablation of nonautomatic focal atrial tachycardia in children with structurally normal hearts.

INTRODUCTION: The majority of children presenting with paroxysmal supraventricular tachycardia (SVT) have either accessory-pathway-mediated tachycardia or AV node reentry tachycardia. The purpose of this study is to report an unusual mechanism of SVT found in children with structurally normal hearts. METHODS AND RESULTS: Records of all patients undergoing an electrophysiology study (EPS) at our institution between 2000 and 2004 were reviewed to identify those with nonautomatic focal atrial tachycardia (NAFAT). Five patients (three males) with an average age of 13.8 years (median 15 years, range 7-18 years) were identified. All presented with paroxysmal palpitations. They all had structurally normal hearts. At EPS, SVT was reproducibly induced with programmed atrial stimulation (single, double, or triple extrastimuli) in all patients. The average cycle length was 276 +/- 9 ms. Adenosine terminated SVT in 2. A 3-D electro-anatomical system mapping was used in all cases. The right atrium (RA) was mapped in all and the left in two. Foci were mapped to the posterior high RA, lateral RA, lower mid RA septum, inferior to the sinus node, and in the right and left posteroseptal areas. Average number of radiofrequency lesions placed was 8.6 +/- 5. The success rate was 80%; there was one late recurrence. No procedural complications were observed. CONCLUSIONS: NAFAT is a rare form of tachycardia that should be considered in the differential diagnosis of children presenting with SVT. It is amenable to mapping and radiofrequency ablation.

[Electroanatomic mapping and radiofrequency catheter ablation of focal atrial tachycardias]. / Ablación con catéter de las taquicardias auriculares focales guiada por mapeo electroanatómico.

Focal atrial tachycardia is defined as supraventricular tachycardia originating from discrete sites from which activation spreads to both atrial. In most clinical series, atrial tachycardia account for about 5% of all supraventricular arrythmias. This tachycardia can occur in children or adults within and without structural heart disease. Three potential mechanisms are described for its origin: abnormal automaticity, triggered activity or microreentry. Catheter ablation has an important role in the management of focal atrial tachycardia and is now considered to be a first line therapy, can be improved with electroanatomical mapping system (CARTO) that allows reconstruction of the chamber geometry and allow visualization of the activation sequence; and can to improve the efficacy of catheter ablation.

Mapeo electroanatómico 3D y ablación percutánea transtorácica de taquicardia auricular en pacientes post cirugía de Fontan / Electro anatomic 3-D mapping and percutaneous transthoracic ablation of atrial tachycardia after Fontan surgery

Introducción: La incidencia de taquicardias auriculares (TA) luego de la operación de Fontan es alta. El acceso a la aurícula pulmonar (AuP) requiere de una punción transeptal o acceso aórtico retrógrado. Se presentan resultados iniciales con una técnica percutánea que permite el acceso a la AuP para mapeo y ablación por radiofrecuencia (ARF). Métodos: Seis EEF con mapeo 3D electroanatómico (CARTO) y ARF se efectuaron en 5 pacientes (1.2 a 17 años). Todos tenían un Fontan (túnel lateral) y TA. Vía transtoráxica se posicionó en la AuP un catéter Navistar para mapeo, estimulación y ARF. Se indujo TA con estimulación programada e isoproterenol. La secuencia de activación, áreas de bloqueo eléctrico y anatómico, y la ubicación del electrograma de His fueron definidas con mapeo 3D electroanatómico. Las zonas de interés fueron estudiadas con técnicas de “entrainment”. Luego de la ARF, el éxito se definió como la imposibilidad de reinducir TA. Resultados: Se encontró taquicardia por reentrada auricular en 5 casos y taquicardia ectópica en uno. La ARF fue exitosa en todos ellos. Hubo 1 pneumotórax y hemotórax en dos casos. En un paciente se observó recurrencia de la TA a los 3 meses, que requirió una segunda ARF, sin nueva recidiva. Ningún paciente esta recibiendo tratamiento antiarrítmico. Resumen: El acceso transtorácico percutáneo a la AuP parece apropiado para mapear y tratar las taquicardias auriculares en pacientes con cirugía de Fontan.

Clasificación de las taquicardias auriculares / Classification of atrial tachycardias

La classificación electrocardiográfica tradicional de las taquicardias auriculares (taquicardia y flúter auricular) no refleja con precisión su mecanismo electrofisiológico. Mediante la cartografia de activación y las técnicas de encarrilamiento podemos diferenciar 2 tipos principales de taquicaria auricular: taquicardia auricular focal y macrorreentrante. Aunque la taquicardia auricular macrorreentrante más comúm es el flúter auricular típico, existen otros muchos tipos de taquicardias macrorreentrantes definidos por la localización del circuito. No hay ninguna característica del ECG, ya sea morfológica o de frecuencia que permita una separación nítida de los mecanismos subyacentes. Sin embargo es posible señalas algunas características clínicas y electrocardiográficas que se associan con frecuencia a un tipo concreto de taquicardia auricular.

Electrocardiogram during tachycardia in patients with anterograde conduction over a Mahaim fiber: old criteria revisited.

OBJECTIVES: The aim of this study was to prospectively evaluate the sensitivity, specificity, and positive and negative predictive values of previously described ECG criteria to identify preexcited tachycardia due to decrementally conducting accessory pathways (QRS axis between 0 and -75 degrees , QRS width < or = 0.15 seconds, an R wave in lead I, an rS pattern in lead V(1), RS > 1 QRS transition > V(4), and cycle length between 220 and 450 ms). BACKGROUND: Preexcited tachycardia associated with decrementally conducting right-sided accessory pathways usually shows a rather "narrow" QRS complex and can be difficult to differentiate from supraventricular tachycardia (SVT) with left bundle branch block (LBBB) aberrant conduction. METHODS: We analyzed three groups of patients: 32 patients with an atriofascicular pathway (group I); 8 patients with long (n = 3) or short (n = 5) decrementally conducting right-sided AV pathway (group II); and a control group that consisted of 35 patients with SVT and LBBB (group III). RESULTS: Presence of all six criteria had 87.5% sensitivity in group I and a 0% sensitivity in group II. There were four false negatives in group I. The negative predictive value was 82.5%, with six false positives in group III (five patients with an aberrant LBBB-shaped tachycardia with ventriculoatrial conduction over an accessory AV pathway). The criterion cycle length was not helpful. CONCLUSIONS: Criteria for identifying a tachycardia with anterograde conduction over a Mahaim fiber are helpful only in atriofascicular pathways, with a sensitivity of 87.5% and a negative predictive value of 82.5%. The major cause of false positives was a tachycardia with aberrant LBBB conduction and ventriculoatrial conduction over an accessory AV pathway.