Enfoque en el diagnóstico diferencial de las taquicardias paroxísticas supraventriculares en el Laboratorio de electrofisiología / Differential diagnosis of paroxysmal supraventricular tachycardia at the electrophysiology laboratory

Resumen: Las taquicardias paroxísticas supraventriculares son arritmias frecuentes y producen importante morbilidad. El estudio electrofisiológico permite hacer el diagnóstico su mecanismo para luego realizar la ablación. El diagnóstico no siempre es sencillo y se debe recurrir a múltiples observaciones y maniobras para alcanzarlo. En la siguiente revisión se discuten los principales criterios usados para el diagnóstico del mecanismo de estas taquicardias durante un estudio electrofisiológico.

Abstract: Paroxysmal supraventricular tachycardias are frequently observed arrhythmias associated to significant morbidity. Electrophysiological study allows the diagnosis of the mechanisms underlying the arrhythmia leading toblation. The diagnosis is not always easy and multiple observations and maneuvers are required to uncover it. In the following review, the main criteria used to diagnose the mechanisms of these tachycardias during an electrophysiological study are discussed.

Diagnóstico diferencial de las taquicardias de complejo ancho: un desafío permanente / Wide QRS tachycardia: a diagnostic challenge

El diagnóstico electrocardiográfico correcto de la causa de una taquicardia de complejo QRS ancho (TCA) es fundamental, ya que tanto el manejo, como el pronóstico del paciente, es diferente según su etiología, y define el estudio que debemos realizar. Numerosos criterios y algoritmos han sido descritos para diferenciar el origen de estas taquicardias. Sin embargo, muchos de estos son complejos y difíciles de aplicar para el médico menos experimentado. Esto es particularmente importante en los servicios de emergencia, donde se necesita una definición rápida que permita un manejo agudo apropiado. En la presente revisión analizamos los diferentes mecanismos de las TCA y los principales criterios diagnósticos en el ECG, reforzando, especialmente, aquellos de aplicación rápida y de alto rendimiento diagnóstico.

The correct electrocardiographic diagnosis of the cause of a wide QRS complex tachycardia (WCT) is essential since both management and prognosis of the patient. The correct electrocardiographic diagnosis of the cause of a wide QRS complex tachycardia (WCT) is essential since both management and prognosis is different according to its etiology and defines the study that we should perform. Numerous criteria and algorithms have been described to differentiate the origin of these tachycardias. However, many of these are complex and difficult to apply to the less experienced doctor. This is particularly important in emergency rooms, where a rapid definition is needed to allow proper therapy. In this review we analyze the different mechanisms of WCT and the main EKG diagnostic criteria, emphasizing those which can be applied rapidly and have high diagnostic value.

Crioablación en taquicardia ortodrómica por vía accesoria oculta parahisiana: caso clínico y revisión de la literatura / Crioablation of orthodromic supraventricular tachycardia win an occult accessory pathway

Abstract An 18-year-old woman with recurrent tachycardia was shown to have orthodromic supraventricular tachycardia through an antero-septal occult pathway near the His. Cryoablation was selected to avoid A-V block. The accesory pathway was finally interrupted after 360 sec of cryoablation. No recurrence was documented after a 12 month follow-up

Taquicardia supraventricular em uma criança / Supraventricular tachycardia in a child

Na presente edição de Pediatria São Paulo é apresentado um caso de taquicardia supraventricular tratado por pediatras, o que ocorre com parcela dos casos. As taquicardias supraventriculares (TSV) são as arritmias sintomáticass mais comuns da criança. A frqueência ventricular média pode variar entre 120 a 330 batimentos por minuto (BPM), com média em torno de 240 bpm. São aspecto eletrofisiológico, as TSV ocorrem por mecanismo de reentrada ou são desencadeadas por foco automático.A TSV pode sser bem tolerada...

The Effects of QRS Duration and Pacing Sites on the Acute Hemodynamic Changes during Right Ventricular Pacing

BACKGROUND: Has been reported that patients exhibiting prolonged paced QRS duration tend to have more serious heart disease, and the paced QRS duration can be an effective indicator of impaired left ventricular function. However, the acute and chronic hemodynamic effects of paced QRS duration and pacing sites during right ventricular (RV) pacing remain unknown. METHODS: A total of 14 patients who underwent electrophysiologic study for paroxysmal supraventricular tachycardia were examined. RV pacing was performed at 10 different sites with cycle lengths of 600 ms and 500 ms utilizing a 6-7F deflectable quadripolar electrode catheter. Systolic, diastolic, and mean blood pressures during pacing were measured once the blood pressure was stabilized. RESULTS: During RV pacing, blood pressures (systolic/diastolic/mean) decreased. The change of post-pacing QRS duration and pre-pacing the systolic blood pressure (SBP) were greater in the group with paced QRS duration. The differences overall were greater than 140 ms. The SBP decrease during pacing was larger in the group exhibiting paced QRS duration of greater than 140 ms. The SBP decrease during pacing showed relation to QRS duration during pacing (r=0.500, p=0.001), the change of QRS duration post-pacing (r=0.426, p=0.001), and SBP during sinus rhythm (r=0.342, p=0.001) on linear correlation analysis. The pacing site, on the other hand, did not affect acute hemodynamic changes during pacing. CONCLUSION: Ventricular pacing of less than 40 ms at the area of paced QRS duration is recommended.

Supraventricular tachycardia in children: a report of three cases, diagnosis and current management

The article presents three Omani children with supraventricular tachycardia and discusses the diagnosis and management. Clinical features along with ECG help diagnosis of this common paediatric arrhythmia. Acute management has been facilitated with the introduction of adenosine. However, longterm management continues to be a topic for debate

Cellular electrophysiology of fast pathway ablation of rabbit atrioventricular node

Discrete radiofrequency lesion at the atrial insertion site of the tendon of Todaro in the perfused rabbit preparation lengthens A-H interval, mimicking fast pathway input ablation. This study attempts to define the cellular electrophysiology of the ablation region prior to and after the elimination of fast AV node conduction. In six superfused rabbit AV node preparations, the cellular electrophysiology around the region of the atrial insertion to the tendon of Todaro was recorded using standard microelectrode technique prior to and after ablation. Before ablation, the action potentials recorded in the area of proposed lesion were exclusively from atrial or AN cells. At postablation, the superior margin of the lesion was populated with atrial or AN cells. AN, N, or NH cells bordered the lower part of the lesion. Electrophysiology of surviving cells at the edges of the lesion showed no significant changes in their Vmax, APD50 or APD90 and MDP from preablation values. Fast AV node pathway input ablation in the rabbit heart can be accomplished with a singular lesion around the atrial insertion site of the tendon of Todaro, involving atrial or AN cells. The results of the studies imply that inputs to the compact node may act as a substrate for successful ablation of AV node reentry tachycardia.

Ablation of manifest left free wall accessory pathways with polarity reversal mapping: ventricular approach

Polarity reversal mapping for localization of the left free wall accessory pathway (AP) at the atrial insertion site has been shown to be effective for successful ablation, but this technique requires atrial septal puncture. We evaluated the safety, efficacy, and reproducibility of two dimensional polarity reversal mapping at the ventricular insertion site of the accessory pathway without atrial septal puncture in symptomatic patients with manifested left free wall AP. Polarity reversal mapping under the mitral annulus by transaortic approach was performed in 10 consecutive patients with conventional ablation catheter (6 French, 4 mm tip, 2 mm interelectrode distance), during sinus rhythm or atrial pacing. A low set high, bandpass filter (0.005-400Hz) was used. Radiofrequency (RF) ablation was performed at the site of ventricular electrocardiogram polarity reversal during sinus rhythm. Polarity reversal was identified in all patients at the ventricular side of the mitral annulus. Ablation was successful in all patients without complications. The procedure time was 86.0 +/- 21.1 min, the fluoroscopic exposure time was 16 +/- 12 min, the number of RF applications was 8 +/- 6, the power level 21 +/- 7 watts, and the time to initial AP block was 3.0 +/- 0.9 sec. Polarity reversal mapping is a safe and efficient technique at the ventricular insertion site. This technique might be complementary to the currently-utilized activation mapping technique.

Uso de la adenosina en la taquicardia paroxística supraventricular / Use of adenosine in paroxysmal supraventricular tachycardia

Los autores presentan cuatro casos de pacientes ingresados al Centro de Cuidados Intensivos del Hospital Central de las Fuerzas Armadas, con diagnóstico de taquicardia paroxística supraventricular. En todos los casos se les realizó maniobras vagales, las que fueron inefectivas para yugular dicha arritmia; a un paciente se le realizó verapamil sin éxito. Todos fueron tratados con adenosina, lográndose excelente respuesta terapéutica, no constatándose efectos secundarios en la utilización de dicho fármaco. Si bien el número de casos no es significativo, se plantea el uso de dicho fármaco en la taquicardia paroxística supraventricular en la cual el nodo aurículo ventricular forma parte del circuito de dicha arritmia.Se realiza una revisión bibliográfica de dicho fármaco, planteándose un protocolo para su utilización

Radiofrequency catheter ablation in idiopathic ventricular tachycardia with structurally normal heart.

In conclusion, we reported two cases of idiopathic right and left VT who presented with syncope and palpitation. The surface QRS during VT and electrophysiologic studies showed the site of origin at RVOT in the first case and inferoapical area of left ventricle in the other. RF ablation was an effective treatment in both patients without any serious complication. Both of them are free of symptoms without any medication.

Comparative clinical and electrophysiologic effects of adenosine and verapamil on termination of paroxysmal supraventricular tachycardia.

The efficacy and electrophysiologic effects of adenosine and verapamil in termination of paroxysmal supraventricular tachycardia (SVT) were compared in 18 patients (age 18-48 years, mean 33 +/- 9 years) with recurrent sustained and inducible SVT. Ten patients had atrioventricular nodal reentrant tachycardia (AVNRT) and 8 had atrioventricular reentrant tachycardia involving a retrograde accessory pathway (cycle length of SVT 280-360 msec; mean 315 +/- 20 msec). Each patient served as his own control. After induction of SVT, adenosine was administered first (6 mg i.v. bolus). If the tachycardia was not terminated, a bolus of 12 mg was given. Ten minutes later, verapamil (5 mg i.v. over 30 sec) was administered after reinduction of SVT. If the tachycardia was not terminated, a 5 mg dose was repeated every 5 minutes upto 20 mg. Adenosine terminated the SVT in 16 cases (6 mg - 7 patients, 12 mg - 9 patients). Verapamil was effective in 11 patients (5 mg - 6 patients, 10 mg - 4 patients, 15 mg - 1 patient, 20 mg - nil). The overall efficacy of adenosine (89%) was significantly greater than that of verapamil (61%; p < 0.05). Adenosine terminated the tachycardia more quickly than verapamil (mean 24 +/- 11 sec versus 142 +/- 40 sec; p < 0.01). Termination of tachycardia by both drugs was related to antegrade block of the atrioventricular node in all patients except one with AVNRT in whom adenosine blocked the retrograde fast pathway. Ventricular premature beats were seen transiently in 5 patients following adenosine. Transient side effects such as flushing, burning and chest pain were frequently observed with adenosine and correlated with the termination of tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Ablaçäo por radiofrequência de taquicardia supraventricular incessante por via anômala de conduçäo retrógrada decremental / Radiofrequency Ablation of Incessant Supraventricular Tachycardia Due to Decremental Retrograde Conduction Via Anomalous Pathways

Woman, 46 years-old with incessant supraventricular tachycardia and tachycardiomyopathy. The diagnosis of a concealed retrograde long conduction time accessory pathway was obtained with the delay of the next atrial activation by delivering a ventricular premature beat during His bundle refratoriness. During electrophysiologic investigation the earliest atrial activation was found to be within the coronary sinus ostium. Two 25 watts applications of radiofrequency were followed by the interruption of the incessant supraventricular tachycardia. The patient has remained symptom free without recurrence for 60 days. Radiofrequency was effective for the treatment of this tachycardia

Resultados tardios da fulguraçäo da junçäo atrioventricular em pacientes com taquicardias supraventriculares utilizando choques de alta energia / Long Term Follow -up After Direct Current Catheter Ablation (High Energy) of the Atrioventricular Junction in Patients with Supraventricular Tachycardias

Purpose - To evaluate the long term efficacy and safety at long term after atrioventricular junction fulguration (complete AV block induction, using high energy shocks, to control drug-resistant supraventricular tachyarrythmias. Methods - Twenty-eigth patients, 17 (60,7%) men, with mean age 48,1 years, were submitted to one up to six ablation sessions with high energy shocks. The total delivered energy per patient was 1304 ± 868 J. Each shock ranged from 100 to 400J. Results - After 12 months, at least, 60,6% of patients were in complete atrioventricular block; three (10,8%) were assymptomatics without complete AV block, and infive (17,8%) the ablation was unsuccessful. Conclusion - AV junction ablation with high energy shocks is safe and efficient in long term follow-up

Objetivo - Avaliar a eficácia a longo prazo da fulguração da junção AV (indução de BAVT), utilizando choques de alta energia, para controle de arritmias supraventriculares refratárias a drogas. Métodos - Vinte e oito pacientes, 17 (60,7%) do sexo masculino, com média etária de 48,1 anos, foram submetidos a uma até seis sessões de fulquração da junção AV, com choques de alta energia. Cada paciente recebeu em média de um a dez choques. A energia total aplicada por paciente variou de 100 a 3200 J (1304 ± 868 J); cada choque foi de 100 a 400J. Resultados - No mínimo após 12 meses, 60,6% dos pacientes permaneceram em BAVT; 3 (10,8%) pacientes apresentam-se assintomáticos, com alterações na condução AV, sem apresentar BAVT. Em 5 (17,8%) pacientes o procedimento foi ineficaz. Conclusão - A fulguração da junção AV (indução de BA VT) com choques de alta energia é procedimento seguro e eficaz a longo prazo

Arritmias infantiles: taquicardias supraventriculares y ventriculares fibrilación. Aleteo / Disrhythmias in children: supraventricular and ventricular tachycardia fibrilation. Flutter

Los autores hacen una revisión de las arritmias propias de la infancia, en cuanto a etiología, patogenia, interpretación del CG. Manifestaciones clínicas, bases del tratamiento y prevención