Ablación por cateter de radiofrecuencia de extrasístoles ventriculares con origen en el seno coronario izquierdo

Las extrasístoles ventriculares (EEVV) son frecuentemente asintomáticas y no requieren de tratamiento antiarrítmico. Las EEVV de los tractos de salida son las EEVV idiopáticas más frecuentes en la práctica clínica. La anamnésis, el examen físico y el electrocardiograma son fundamentales en el diagnóstico. Aunque las EEVV de los tractos de salidas ventriculares son consideradas benignas, pueden producir diversos síntomas y desencadenar una cardiomiopatía inducida por las extrasístoles, que lleva a un deterioro de la función sistólica ventricular izquierda y en última instancia, insuficiencia cardiaca. Cuando el tratamiento farmacológico de las EEVV fracasa, nos queda la ablación de arritmias por catéter de radiofrecuencia como única alternativa eficaz. Este es el caso de la paciente de sexo femenino de 62 años, hipertensa, dislipidémica y tabaquista, que demuestra la seguridad de la ablación por catéter de radiofrecuencia, la eficacia terapéutica, y el restablecimiento integro de la función ventricular del corazón.

Premature ventricular complexes (PVC) are frequently asymptomatic and do not require antiarrhythmic treatment. Outflow tract PVC are the most common idiopathic PVC in clinical practice. The anamnesis, physical examination and electrocardiogram are essential in the diagnosis of these patients. Although PVC of the ventricular outflow tracts are considered benign, they can produce various symptoms such as dyspnea on exertion, asthenia, palpitations, dizziness, presyncope or syncope, and in those patients with very high arrhythmic burden (>24% on a 24-hour Holter monitoring), can trigger extrasystole-induced cardiomyopathy, leading to deterioration of left ventricular systolic function and ultimately heart failure. When pharmacological treatment of PVC fails, ablation of arrhythmias by radiofrequency catheter is the only effective alternative. This is the case of the 62-year-old female patient, hypertensive, dyslipidemic and a smoker, which demonstrates the safety of radiofrequency catheter ablation, the therapeutic efficacy, and the complete restoration of the ventricular function of the heart.

Resultados del aislamiento eléctrico de las venas pulmonares en pacientes menores y mayores de 70 años / Outcomes of pulmonary vein electrical isolation in patients younger than and older than 70 years

Resumen Introducción y objetivos: Comparar las características clínicas y los resultados de cohortes contemporáneas de pacientes menores y mayores de 70 años que han sido sometidos a ablación de fibrilación auricular (FA) mediante catéter. Métodos: Se llevó a cabo un estudio de cohortes retrospectivo en pacientes sometidos a ablación con catéter debido a la presencia de FA refractaria. Se realizó un seguimiento mínimo de 12 meses por paciente. Resultados: En el estudio se incluyeron un total de 239 pacientes sometidos a ablación de FA, de los cuales 171 (71,5%) pertenecían al grupo de edad < 70 años y 68 (28,5%) al grupo de edad > 70 años. La edad promedio de la población estudiada fue de 62,4 años (desviación estándar [DE] = 10,87). El grupo < 70 años presentó una edad promedio de 58,03 años (DE = 9,71), mientras que el grupo > 70 años tuvo una edad promedio de 73,4 años (DE = 3,05). Además, se observó una mayor prevalencia de FA paroxística en el grupo de pacientes menores de 70 años, mientras que en el grupo de pacientes mayores de 70 años se encontró una mayor prevalencia de FA persistente. Estas diferencias fueron estadísticamente significativas en ambos casos. Las tasas de recurrencia después del primer procedimiento de ablación fueron similares entre los dos grupos (21,43% en el grupo menor de 70 años frente a 23,53% en el grupo mayor de 70 años, p = 0,79). No se encontraron diferencias significativas en cuanto a complicaciones. El grupo menor de 70 años experimentó 18 complicaciones, mientras que el grupo mayor de 70 años tuvo 5 complicaciones, con un valor de p de 0,472. Conclusión: Los pacientes mayores de 70 años sometidos al primer procedimiento de ablación de FA por catéter presentan resultados clínicos similares a los pacientes menores de 70 años.

Abstract Introduction and objectives: The objective of this study is to compare the clinical characteristics and outcomes of contemporary cohorts of patients undergoing catheter ablation for atrial fibrillation (AF), stratified by age (< 70 years and ≥ 70 years). Methods: This retrospective cohort study included patients who underwent catheter ablation for refractory AF. The minimum follow-up duration per patient was 12 months. Results: A total of 239 patients were included in the study, with 171 (71.5%) in the < 70 years group and 68 (28.5%) in the ≥ 70 years group. The mean age of the study population was 62.4 years (SD 10.87). The < 70 years group had a mean age of 58.03 years (SD 9.71), while the ≥ 70 years group had a mean age of 73.4 years (SD 3.05). Furthermore, a higher proportion of paroxysmal AF was observed in patients < 70 years, whereas a higher proportion of persistent AF was found in patients ≥ 70 years. These differences were statistically significant. The recurrence rates after the initial ablation procedure were similar between the two groups (21.43% in the < 70 years group vs. 23.53% in the ≥ 70 years group, p = 0.79). Additionally, there were no significant differences in terms of complications. The < 70 years group experienced 18 complications, while the ≥ 70 years group had 5 complications (p = 0.472). Conclusion: The findings of this study suggest that patients aged 70 years and older who undergo their first catheter ablation procedure for AF demonstrate similar clinical outcomes compared to patients younger than 70 years.

[Outcomes of pulmonary vein electrical isolation in patients younger than and older than 70 years]. / Resultados del aislamiento eléctrico de las venas pulmonares en pacientes menores y mayores de 70 años.

Introduction and Objectives: The objective of this study is to compare the clinical characteristics and outcomes of contemporary cohorts of patients undergoing catheter ablation for atrial fibrillation (AF), stratified by age (< 70 years and ≥ 70 years). Methods: This retrospective cohort study included patients who underwent catheter ablation for refractory AF. The minimum follow-up duration per patient was 12 months. Results: A total of 239 patients were included in the study, with 171 (71.5%) in the < 70 years group and 68 (28.5%) in the ≥ 70 years group. The mean age of the study population was 62.4 years (SD 10.87). The < 70 years group had a mean age of 58.03 years (SD 9.71), while the ≥ 70 years group had a mean age of 73.4 years (SD 3.05). Furthermore, a higher proportion of paroxysmal AF was observed in patients < 70 years, whereas a higher proportion of persistent AF was found in patients ≥ 70 years. These differences were statistically significant. The recurrence rates after the initial ablation procedure were similar between the two groups (21.43% in the < 7 0 years group vs. 23.53% in the ≥ 70 years group, p = 0.79). Additionally, there were no significant differences in terms of complications. The < 70 years group experienced 18 complications, while the ≥ 70 years group had 5 complications (p = 0.472). Conclusion: The findings of this study suggest that patients aged 70 years and older who undergo their first catheter ablation procedure for AF demonstrate similar clinical outcomes compared to patients younger than 70 years.

Introducción y objetivos: Comparar las características clínicas y los resultados de cohortes contemporáneas de pacientes menores y mayores de 70 años que han sido sometidos a ablación de fibrilación auricular (FA) mediante catéter. Métodos: Se llevó a cabo un estudio de cohortes retrospectivo en pacientes sometidos a ablación con catéter debido a la presencia de FA refractaria. Se realizó un seguimiento mínimo de 12 meses por paciente. Resultados: En el estudio se incluyeron un total de 239 pacientes sometidos a ablación de FA, de los cuales 171 (71,5%) pertenecían al grupo de edad <70 años y 68 (28,5%) al grupo de edad >70 años. La edad promedio de la población estudiada fue de 62,4 años (desviación estándar [DE] = 10,87). El grupo <70 años presentó una edad promedio de 58,03 años (DE = 9,71), mientras que el grupo >70 años tuvo una edad promedio de 73,4 años (DE = 3,05). Además, se observó una mayor prevalencia de FA paroxística en el grupo de pacientes menores de 70 años, mientras que en el grupo de pacientes mayores de 70 años se encontró una mayor prevalencia de FA persistente. Estas diferencias fueron estadísticamente significativas en ambos casos. Las tasas de recurrencia después del primer procedimiento de ablación fueron similares entre los dos grupos (21,43% en el grupo menor de 70 años frente a 23,53% en el grupo mayor de 70 años, p = 0,79). No se encontraron diferencias significativas en cuanto a complicaciones. El grupo menor de 70 años experimentó 18 complicaciones, mientras que el grupo mayor de 70 años tuvo 5 complicaciones, con un valor de p de 0,472. Conclusión: Los pacientes mayores de 70 años sometidos al primer procedimiento de ablación de FA por catéter presentan resultados clínicos similares a los pacientes menores de 70 años.

Limitations of Baseline Impedance, Impedance Drop and Current for Radiofrequency Catheter Ablation Monitoring: Insights from In silico Modeling.

Background: Baseline impedance, radiofrequency current, and impedance drop during radiofrequency catheter ablation are thought to predict effective lesion formation. However, quantifying the contributions of local versus remote impedances provides insights into the limitations of indices using those parameters. Methods: An in silico model of left atrial radiofrequency catheter ablation was used based on human thoracic measurements and solved for (1) initial impedance (Z), (2) percentage of radiofrequency power delivered to the myocardium and blood (3) total radiofrequency current, (4) impedance drop during heating, and (5) lesion size after a 25 W−30 s ablation. Remote impedance was modeled by varying the mixing ratio between skeletal muscle and fat. Local impedance was modeled by varying insertion depth of the electrode (ID). Results: Increasing the remote impedance led to increased baseline impedance, lower system current delivery, and reduced lesion size. For ID = 0.5 mm, Z ranged from 115 to 132 Ω when fat percentage varied from 20 to 80%, resulting in a decrease in the RF current from 472 to 347 mA and a slight decrease in lesion size from 5.6 to 5.1 mm in depth, and from 9.2 to 8.0 mm in maximum width. In contrast, increasing the local impedance led to lower system current but larger lesions. For a 50% fat−muscle mixture, Z ranged from 118 to 138 Ω when ID varied from 0.3 to 1.9 mm, resulting in a decrease in the RF current from 463 to 443 mA and an increase in lesion size, from 5.2 up to 7.5 mm in depth, and from 8.4 up to 11.6 mm in maximum width. In cases of nearly identical Z but different contributions of local and remote impedance, markedly different lesions sizes were observed despite only small differences in RF current. Impedance drop better predicted lesion size (R2 > 0.93) than RF current (R2 < 0.1). Conclusions: Identical baseline impedances and observed RF currents can lead to markedly different lesion sizes with different relative contributions of local and remote impedances to the electrical circuit. These results provide mechanistic insights into the advantage of measuring local impedance and identifies potential limitations of indices incorporating baseline impedance or current to predict lesion quality.

Real-world data meta-analysis: procedural success and clinical outcomes after radiofrequency ablation of atrial fibrillation in South America.

OBJECTIVE: To profile patients' characteristics, in-hospital results, and recurrence rates after radiofrequency ablation of atrial fibrillation (RAAF) in South America. METHODS: We comprehensively searched for single-center studies from South America with ≥10 patients receiving RAAF, published or presented from January 1, 2010, through June 29, 2020, excluding those reports aimed to specific populations such as permanent atrial fibrillation, structural cardiopathies, or re-do procedures. RESULTS: Main pooled estimates from a random-effects meta-analysis that included 3909 patients from 27 cohorts (from 5 countries): a) Patients characteristics: age 57.6 years (95% CI 55.7-59.5), male gender 71.5% (95% CI 67.0-75.6%), hypertension 54.2% (95% CI 45.4-62.8%), paroxysmal atrial fibrillation 79.8% (95% CI 71.3-94.5%), CHADS score 1.2 (95% CI 0.5-1.9), b) Acute procedural success 91.1% (95% CI 82.2-95.8%), c) In-hospital complications: stroke 0.6% (95% CI 0.3-1.2%), cardiac tamponade 2.3% (95% CI 1.4-3.7), hematoma 3.5% (95% CI 2.0-6.1), pseudoaneurysm 1.2% (95% CI 0.6-2.3), arteriovenous fistula 2.5% (95% CI 1.6-4.1). There were no cases of esophageal-atrial fistula nor death. Pooled estimate for arrhythmia recurrence (excluded 3-months blanking period) at 12 months was 19.9% (95% CI 17.0-23.1). CONCLUSION: In-hospital results of RAAF reported for South American centers were worse than published international registries, even when included populations profile was of lower risk, as reflected in younger age and less prevalence of non-paroxysmal AF. Late recurrence rates seemed appropriate. This study provides a real-life framework for the analysis of the performance of this technology in the region.

Epicardial ablation of incessant left atrial appendage tachycardia in a case with tachycardiomyopathy.

Atrial tachycardias originated at the left atrial appendage (LAA) are uncommon; often they are incessant and might induce tachycardiomyopathy, as discussed by Hillock et al. (Heart Rhythm;3(4):467-469, 2006). A case of a 21-year-old woman with incessant atrial tachycardia is presented, refractory to medical therapy, echocardiography showed global dilation with LV ejection fraction of 20%. After two failed endocardial ablations, an epicardial access was attempted. The earliest activation site was located at the tip of the epicardial aspect of the LAA. RFCA was successful at this site. The patient remains asymptomatic during a follow-up of 10 months; the ventricular function was completely recovered after 6 months (LVEF of 50%).

Atrial-oesophageal fistula following percutaneous radiofrequency catheter ablation of atrial fibrillation: the risk still persists.

Aims: Atrial-oesophageal fistula is a serious complication related to ablation of atrial fibrillation. As its occurrence is rare, there is a great lack of information about their mechanisms, incidence, presentations, and treatment. The objective of this manuscript is to present a series of cases of atrial-oesophageal fistula in Brazil, focusing on incidence, clinical presentation, and follow-up. Methods and results: This is a retrospective multicentre registry of atrial-oesophageal fistula cases that occurred in eight Brazilian centres from 2003 to 2015. Ten cases (0.113%) of atrial-oesophageal fistula were reported in 8863 ablation procedures in the period. Most of the subjects were male (70%) with age 59.6 ± 9.3 years. Eight centres were reference units in atrial fibrillation ablation with an experience over than 200 procedures at the time of fistula occurrence. Oesophageal temperature monitoring was performed in eight cases using coated sensors in six. The first atrial-oesophageal fistula clinical manifestation was typically fever (in six patients), with a median onset time of 16.5 (12­43) days after ablation. There was a delay of 7.8 ± 3.3 days between the first manifestation and the diagnosis in five patients. The treatment was surgical in six cases, clinical in three and stenting in one. Seven patients died (70%) and two developed permanent neurological sequelae. Conclusion: Atrial-oesophageal fistula remains a serious complication following AF ablation despite the incorporation of protective measures and increased technical experience of the groups. The high morbidity and mortality despite the treatment indicates the need to develop adequate preventive strategies.

Differentiating origins of outflow tract ventricular arrhythmias: a comparison of three different electrocardiographic algorithms

Our objective is to evaluate the accuracy of three algorithms in differentiating the origins of outflow tract ventricular arrhythmias (OTVAs). This study involved 110 consecutive patients with OTVAs for whom a standard 12-lead surface electrocardiogram (ECG) showed typical left bundle branch block morphology with an inferior axis. All the ECG tracings were retrospectively analyzed using the following three recently published ECG algorithms: 1) the transitional zone (TZ) index, 2) the V2 transition ratio, and 3) V2 R wave duration and R/S wave amplitude indices. Considering all patients, the V2 transition ratio had the highest sensitivity (92.3%), while the R wave duration and R/S wave amplitude indices in V2 had the highest specificity (93.9%). The latter finding had a maximal area under the ROC curve of 0.925. In patients with left ventricular (LV) rotation, the V2 transition ratio had the highest sensitivity (94.1%), while the R wave duration and R/S wave amplitude indices in V2 had the highest specificity (87.5%). The former finding had a maximal area under the ROC curve of 0.892. All three published ECG algorithms are effective in differentiating the origin of OTVAs, while the V2 transition ratio, and the V2 R wave duration and R/S wave amplitude indices are the most sensitive and specific algorithms, respectively. Amongst all of the patients, the V2 R wave duration and R/S wave amplitude algorithm had the maximal area under the ROC curve, but in patients with LV rotation the V2 transition ratio algorithm had the maximum area under the ROC curve.

Resultados preliminares de la seguridad y eficacia en el tratamiento híbrido endoluminal de la incompetencia de la vena safena mayor / Preliminary results of the safety and efficacy with a hybrid treatment of insufficiency of the great saphenous vein

Introducción: en el tratamiento de la incompetencia de la safena mayor la radiofrecuencia y el láser se han asociado a neuralgia y otras complicaciones, debido a extensión de la lesión térmica. La escleroterapia con espuma abre un nuevo horizonte en el tratamiento de venas más complejas, alcanzando sin dolor las dilataciones epifasciales. Existe preocupación acerca de si esta técnica en el manejo de lesión troncular, eleva la posibilidad de una reapertura de la unión safeno-femoral. Nuestro grupo desarrolló un abordaje híbrido con termo-ablación con radiofrecuencia y esclero-espuma. Métodos: se incluyeron 87 pacientes con clasificación CEAP de C2-C4 con incompetencia y dilatación de la safena mayor documentado por ecografía dúplex. El manejo híbrido se realizó mediante acceso percutáneo ecoasistido de la safena mayor con el catéter corto de radiofrecuencia VNUS ClosureFAST, 2 cm distal a la unión safeno-femoral y bajo anestesia infiltrativa. Se llevó a cabo la termo-ablación de la unión safeno-femoral y safena mayor subyacente. Previo a la extracción del catéter se inyectaron 8 cc de espuma de cloruro de lapirio al 1 % en todos los casos (tasa de preparación con técnica de Tessari de 4:1). El seguimiento se llevó a cabo durante seis meses e incluyó dúplex de la pierna tratada para establecer la oclusión de la safena mayor y unión safeno-femoral. Resultados: 83 pacientes completaron el seguimiento. A 78 pacientes se les detectó oclusión de la safena mayor y unión safeno-femoral al sexto mes postoperatorio y cinco requirieron una segunda dosis de espuma en el segmento recanalizado. Siete pacientes reportaron dolor en el área inguinal en el postoperatorio inmediato. No se presentaron complicaciones mayores. Conclusiones: este es un reporte preliminar de un procedimiento híbrido que involucra el uso de energía térmica para ocluir completamente la unión safeno-femoral y tratar en el mismo tiempo quirúrgico la safena mayor y dilataciones epifasciales asociadas, sin la necesidad de utilizar energía térmica en el tronco safeno o el uso de flebectomía complementaria. La tasa de oclusión parece prometedora, pero es necesario un mayor seguimiento para poder establecer su verdadero alcance.

ABSTRACT Background: Treating the insufficiency of the Greater saphenous vein (GSV), using radiofrequency (RF) and LASER ablation have been associated to neuralgia and other complications due to the extension of the thermal injury. Foam sclerotherapy opened a new trend in the treatment of larger veins, reaching superficial varicosities, but the treatment of the GSV, raises the possibility of a quick reopening of the saphenofemoral junction (SFJ). Our group developed an approach that merges the benefits of thermal injury and foam sclerotherapy. Methods: 87 patients classified as C2-C4 (CEAP classification), 73 female, mean age: 58.4 with incompetence and dilatation of GSV where included in this study. Our Hybrid procedure was performed using ultrasound guided percutaneous access of GSV with a new short RF catheter (VNUS Closure FAST) distal to the SFJ under local anaesthesia. Thermal occlusion of the saphenofemoral junction (SFJ) and GSV subjacent segment was achieved. Just before retrieving the device, we injected 8cc of 1 % Lapidium Chloride foam using physiological gas. Duplex ultrasound was carried out to assess GSV and SFJ occlusion; follow-up was at completed 6 months. Results: 83 patients completed the follow-up period. 78 patients had their GSV and SFJ occluded at 6 months demonstrated by duplex ultrasound and 5 required a second dose of foam sclerotherapy. Four patients were lost during follow-up due to change of address. Seven patients reported pain in the groin area immediately after the procedure. There were no major complications. Conclusions: This is a preliminary report of a hybrid procedure that involves use of thermal energy to occlude the SFJ and treat at the same time the GSV and associated varicosities, without the need for further thermal usage of the venous trunk or the use of phlebectomy. This hybrid procedure combines the best of this two techniques, minimizing their disadvantages and potentiating their advantages. The occlusion rate seems promising but further studies should evaluate its effectiveness in time.

Estudio electrofisiológico y ablación de actividad eléctrica anormal en venas pulmonares de pacientes con fibrilación auricular paroxística idiopática / Electrophysiologic study and ablation therapy in idiopathic paroxystic atrial fibrillation

Objetivo: Informar la ablación en las venas pulmonares (VPs) en pacientes con fibrilación auricular paroxística (FAP). Material y métodos: Catorce pacientes (38±12 años [intervalo 8-52, 11 hombres, 3 mujeres) con FAP idiopática, sintomática y refractarios a antiarrítmicos y con estudio electrofisiológico. En 13 se encontró actividad eléctrica anormal (AEA) en VPs mediante catéteres especiales de cartografía y se realizó ablación. Resultados: Se identificó AEA en VP’s (13 pacientes, 86%) y en vena cava superior (un paciente, 6.6%). Un procedimiento fue suspendido por taquicardia ventricular. La ablación fue exitosa en 7 de los 12 pacientes restantes. Los cinco pacientes con ablación inicial fallida fueron llevados a un segundo procedimiento que fue exitoso en dos. En un paciente fue necesario un tercer procedimiento que resultó exitoso. Una paciente tuvo pericarditis con derrame ligero que no requirió drenaje. Conclusión: La ablación de FAP es un procedimiento seguro con una tasa de éxito combinada (con y sin antiarrítmicos) en esta población y a largo plazo, del 71%.

OBJECTIVE: To analyze the results of radiofrequency catheter ablation (RFCA) of the pulmonary veins (PV) in patients with paroxysmal atrial fibrillation (PAF). MATERIAL AND METHODS: We describe 4 patients (38 +/- 12 years, interval 8-52; 11 men) with symptomatic PAF, refractory to antiarrhythmic drugs. Special mapping catheters were used and ablation was performed at the ostium/antrum of those veins with abnormal electrical activity (AEA). RESULTS: AEA in one or more PV was identified in 13 patients (86%); in one patient AEA was also found in the superior vena cava (6.6%). One procedure was complicated by unstable ventricular tachycardia and was notfinished. Success was accomplished in 10, in 5 after the first ablation, in 4 after the second, and in one after a third procedure. One patient had pericarditis with a small pericardial effusion that did not require intervention. CONCLUSIONS: RFCA is a useful and relatively safe procedure for the treatment of PAF and the only one with curative potential. The long-term rate of success (with or without antiarrhythmics) in this series was 71%. These results justify catheter ablation in selected patients with symptomatic PAF unresponsive to medical treatment.

Seguimiento a largo plazo en 413 pacientes con vía accesoria atrioventricular sometidos a ablación con radiofrecuencia

Objetivo: se analizan los resultados clínicos y el seguimiento a largo plazo de los pacientes que fueron sometidos a ablación endocárdica mediante radiofrecuencia para el tratamiento de la taquicardia paroxística supraventricular por vía accesoria atrioventricular. Material y métodos: se incluyeron 413 pacientes a quienes se les realizó ablación con radiofrecuencia de vías accesorias atrioventricular de abril de 1992 a diciembre de 1995. Resultados: de los 413 pacientes seleccionados, 234 (57%) eran hombres y 179 (43%) eran mujeres, con edad promedio de 31.3 ± 16.3 años (límites 2 a 69 años). Se localizó un total de 437 vías accesorias atrioventriculares, 389 (93)% eran únicas y en 24 enfermos estuvieron presentes dos vías accesorias. La ablación tuvo éxito inmediato en 381 vías atrioventriculares (87%), durante el seguimiento promedio de siete años, se observó recurrencia de 51 vías atrioventriculares (13%), de estas 41 (80%) recurrieron en los primeros tres meses. A cincuenta y seis pacientes se les realizó una segunda sesión de ablación, con éxito de 35 (62.5%) y nueva recurrencia en 2 (5.7%). Son 365 vías accesorias (83.5) que permanecen sin recurrencia de taquicardia o preexcitación. Conclusiones: durante el seguimiento, los efectos de la ablación exitosa con RF se preservan en el tiempo. La taquicardia identificada en recurrencia siempre correspondió al mecanismo de reentrada a través de la vía accesoria.

Objective: the aim of this study was shown clinical characteristics and follow-up of patients with atrioventricular reentrant tachycardia (AVRT) who underwent radiofrequency catheter ablation (RCA) therapy. Material and Methods: from April 1992 to December 1995, 413 patients with AVRT underwent RCA therapy. Results: two hundred thirty four men (57%) and one hundred seventy nine women (43%) aged 31.3 ± 16-3 years were studied. 437 single accessory pathways were found; 24 had multiple accessory pathways. Ablation therapy was successful in 381 accessory pathways. During follow-up of 7 years, AVRT recurred in 51 patients (13%) and in 80% this occurred within the first 3 months after the procedure. 56 patients underwent a second RCA therapy with success in 35 patients (83.5); two reoccurred (5.7%); 365 accessory pathways (83.5) remained without evidence of preexcitation AVRT. Conclusions: during follow-up, these patients with successful ablation therapy remained without symptoms. In patients who underwent a second RCA therapy, atrioventricular reentrant mechanism was always present.

Palpitações persistentes após ablação por cateter com radiofreqüência / Persistence of Palpitations After Successful Radiofrequency Catheter Ablation

PURPOSE: The aim of this study was to determine prevalence and the underlying mechanism of persistent palpitations after successful radiofrequency ablation of reentrant nodal tachycardia and atrioventricular tachycardia. METHODS: One hundred twenty consecutive patients (mean age of 36 +/- 16 years) who underwent radiofrequency catheter ablation of atrioventricular or reentrant nodal tachycardia constituted the analyzed group. Prevalence of palpitations was investigated during out-clinic visits and telephone interviews. Patients complaining of palpitations were divided in 2 groups: 1) those in whom palpitations lasted more than 30 seconds, and 2) those in whom the paroxysms lasted < 30 seconds (group II). All patients underwent clinical evaluation, ECG and Holter monitoring. Transesophageal atrial pacing and electrophysiologic stimulation were carried out when judged necessary. RESULTS: During a follow up period of 9 +/- 4 months, 52 patients complained of palpitations. In 31 group I patients, palpitations were related to ventricular and atrial premature beats as shown during Holter monitoring. In group II patients, eight had recurrence, five presented a new arrhythmia not recognized previously to the ablative procedure and two patients had their symptoms related to arrhythmias recognized before ablation but taken as asymptomatic. The mechanism of palpitations was not identified in six patients. CONCLUSION: Palpitations may persist in 43of patients who undergo radiofrequency ablation to treat reentrant nodal tachycardia and atrioventricular tachycardia. Recurrence and treatment are more likely when palpitations last longer than 30 seconds.

Análise das características do ritmo juncional em pacientes com taquicardia por reentrada nodal submetidos a ablação da via lenta por radiofreqüência / Characteristics of Junctional Rhythm During Radiofrequency Catheter Ablation of Slow Pathway in Atrioventricular Nodal Reentrant Tachycardia

PURPOSE--To study the quantitative and qualitative aspects of junctional rhythm (JR) during radiofrequency (RF) catheter ablation of slow pathway in atrioventricular nodal reentrant tachycardia. METHODS--Twenty five patients, 5 males, ages ranging from 15 to 76 years, with recurrent atrioventricular nodal reentrant tachycardia, underwent to RF catheter ablation of slow pathway. During RF applications (40V, duration 60s) electrocardiographic was continuously recorded. The recordings were posteriorly used to study the presence and characteristics of JR (number of episodes, frequency and time of onset) at the effective and ineffective RF sessions. All variables were expressed as median and mean +/- SD. Univariate analysis of the effects of each variable on success or failure of ablation were performed using x2 test. A p value < 0.05 was considered significant. RESULTS--One hundred forty nine RF sessions were performed, 25 effective and 124 ineffective (mean per patient 6, range 1 to 22). JR was present in 18 of 25 effective and 44 of 124 ineffective sessions (p < 0.05). Mean time of appearance was 12s, occurring later this time in 9 of 18 effective and in 10 of 44 ineffective sessions (p < 0.05). Mean number of episodes was 3, occurring higher number in 7 of 18 effective and in 4 of 44 ineffective sessions (p < 0.05). Median of frequency of JR was 100bpm; 11 of 18 effective and 15 of 44 ineffective sessions presented higher frequencies (p < 0.05). CONCLUSION--JR during slow pathway ablation is a sensitive marker of ablation success. JR predictor of success has higher number of episodes, higher frequency and later time of appearance than that one of ineffective sessions.

Objetivo - Estudar quantitativa e qualitativamente as características do ritmo juncional (RJ) ocorrido durante o procedimento de ablação por cateter da via lenta, em pacientes com taquicardia por reentrada nodal. Métodos - Vinte e cinco pacientes (5 homens, 15 a 76 anos) foram submetidos a ablação por cateter da via lenta, utilizando radiofreqüência (RF). Durante as sessões de RF de 40V, com 1min de duração, foi realizado o registro eletrocardiográfico contínuo, na velocidade de 25mm/s. Os registros serviram, posteriormente, para análise da presença e das características do RJ (número de episódios, freqüência e tempo de aparecimento após o início da RF), nas sessões eficazes e ineficazes. As variáveis estudadas foram expressas em mediana, média e desvio-padrão. A análise univariada do efeito das mesmas no sucesso da ablação foi realizada, utilizando-se o teste do qui-quadrado. Valor de p<0,05 foi considerado significante. Resultados - Foram realizadas 149 sessões de RF (média de 6/paciente, variando de 1 a 22), sendo 25 eficazes e 124 ineficazes. O RJ esteve presente em 18 de 25 sessões eficazes e em 44 de 124 ineficazes (p<0,05). A média do tempo de aparecimento do RJ após o início da RF foi de 12s, aparecendo em tempo superior à média em 9 de 18 sessões eficazes e em 10 de 44 ineficazes (p<0,05). A média do número de episódios de RJ foi 3, sendo maior que a média em 7 de 18 sessões eficazes e em 4 de 44 ineficazes (p<0,05). A mediana da freqüência do RJ foi de 100bpm, sendo maior que esse valor em 11 de 18 sessões eficazes e em 15 de 44 ineficazes (p<0,05). Conclusão - O RJ durante ablação com RF é um marcador sensível do sucesso do procedimento. O RJ preditor de sucesso apresenta número maior de episódios, freqüência cardíaca mais elevada e aparece mais tardiamente durante o pulso de RF, quando comparado ao que resulta ineficaz

Terapia ablativa do flutter atrial tipo I com radiofreqüência / Type I Atrial Flutter Ablation Therapy with Radiofrequency

PURPOSE--To present initial experience on radiofrequency (RF) ablation of atrial flutter (AFL) guided by anatomic and electrophysiologic parameters. METHODS--Eight patients (six males), mean-age of 42 +/- 17.5 years with chronic type I AFL (mean cycle length of 251 +/- 14.3 msec, range 240 to 280 msec) were undergone to RF catheter ablation applied between inferior vena cava (IVC) and tricuspid annulus (TA). Two had persistent and two the paroxysmal form. Two had surgical corrected congenital heart disease (atrial septal defect in 2 and ventricular septal defect in 1). Four had systolic dysfunction and 2, an atrial tachycardia associated with the AFL. RESULTS--Areas of slow conduction represented by fractionated potentials were recorded between IVC and TA in all patients. RF ablation was successful in 8/8 patients (100). The mean number of RF applications was 9.2 +/- 6.2 (4-24). The successful ablation site was located in the isthmus between IVC and TA in seven patients and in the lateral wall in the patient with ASD. Successful sites had an early atrial activation preceding the atrial electrogram (range from -65 to -82 ms). In one patient the RF energy was successfully delivered between the atriotomy scar (AS) and IVC. After three months follow-up six remained free of recurrent AFL. One pt had type 1 AFL recurrence and one with ASD had a type II AFL. The Type II AFL was successfully ablated between AS and IVC. CONCLUSION--Fractionated potentials were commonly observed between IVC and T; AFL ablation can be guided by anatomic landmarks or electrophysiologic parameters; electrograms recorded at successful sites were early and never fractionated; the long-term evaluation must be analyzed prospectively.

Ablação com radiofreqüência do flutter atrial tipo I / Radiofrequency catheter ablation of type I atrial flutter

PURPOSE--To verify the efficacy and safety of the creation of a barrier with radiofrequency (RF) in the tricuspid annulus and the vena cava ostium (TA-IVC). METHODS--Nine consecutive patients, 7 males, with age ranging from 36 to 76 years, with paroxysmal (7 patients) or permanent (2) type I atrial flutter (negative P wave in lead II, III and F) were submitted to RF ablation of TA-IVC istmo. One deflectable catheter with 4mm size tip was introduced into the right ventricle apex and pulled back to the inferior vena cava. When the atrial electrogram was detected the RF application was started. The RF was applied (20 watts during 60s) up to the proximity of inferior vena cava ostium. The end point was to stop atrial flutter. Then a vigorous atrial stimulation protocol, including isoproterenol infusion was used. In the next day, patients were submitted to transesophageal stimulation with the same protocol. RESULTS--Atrial flutter was interrupted in all patients (100//) with 4 to 28 (mean 16.7 +/- 7.7) applications. Eight patients (88.8//) with one session and 1 (11.1//) with two sessions. The mean time spent to stop the atrial flutter with one application was 30.5 +/- 18.5s. There were no complications. After a mean follow up of 3 +/- 1.6 month all patients (100//) are asymptomatic. Two of them are taking propranolol to control symptomatic atrial and ventricular ectopic beats. CONCLUSION--RF ablation of the TA-IVC istmo is efficient and safe in a short term follow up to interrupt and prevent re-induction and recurrence of type I atrial flutter