Atrial fibrillation: an observational study with outpatients.

BACKGROUND: Atrial fibrillation (AF) is the most common sustained arrhythmia with serious clinical consequences in the absence of treatment. However, there are limited data on the treatment of these patients in Argentina. The objective was to describe the therapeutic management of patients with nonacute AF by Argentinean cardiologists and to determine the incidence of clinical events after 12 months follow-up. METHODS: The Atrial Fibrillation study in Argentina (FARAON) was an observational, descriptive, prospective, national, and multicentric study that included outpatients with AF, followed for 12 months. The study included 38 sites in Argentina. Each researcher included the first 10 patients who met the inclusion criteria of being over 21 and also being an AF carrier documented by electrocardiogram or Holter within 12 months prior to or at the time of enrollment. RESULTS: A total of 373 patients were included, mean age 70 ± 11.5 years, 40% women; 65% had AF rhythm at the time of inclusion, 57% had permanent AF, and 56% were asymptomatic. At the time of enrollment, 40% of physicians opted for rhythm control strategy. ß-blockers and amiodarone were the most used drugs. Patients with rhythm control drugs had higher success rate than those with frequency control drug therapy (80% vs 57%). CONCLUSION: Cardiologists in Argentina receive patients with AF that are mostly permanent AF. More than half of the patients are asymptomatic. They opt primarily by controlling the pace. When choosing antiarrhythmic drugs, nearly half of them indicated amiodarone.

Updated results on catheter ablation of ventricular arrhythmias arising from the papillary muscles of the left ventricle.

BACKGROUND: Catheter ablation of ventricular arrhythmias (VAs) arising from the left ventricle`s (LV) papillary muscles (PM) is challenging. In this study we present results of catheter ablation using multiple energy sources and image-based approaches. METHODS: Fifty-three patients (49 ± 17 years old; 34% females; median LV ejection fraction 53 ± 11%) underwent catheter cryoablation or radiofrequency (RF) ablation with non-contact force sensing (Non-CFS) catheters and cardiac computed tomography integration (CTII) into the electroanatomical mapping system or contact force sensing RF (CFS RF) ablation catheters and intracardiac echo-facilitated 3D electroanatomical mapping. Ventricular arrhythmias foci were mapped at either the anterolateral (ALPM) or posteromedial papillary muscles (PMPM). Ablation was performed using an 8-mm cryoablation catheter (CRYO); a Non-CFS 4-mm open-irrigated RF catheter; or a CFS RF 3.5-mm open-irrigated tip catheter, via transmitral or transaortic approach. RESULTS: Acute success rate was 83% for Non-CFS RF/CTII; 100% for CRYO/CTII (n = 16) and CFS RF/ICE3D (n = 14) (P = 0.03). Catheter stability was achieved in all patients treated with Cryo/CTII. VA recurrence at 12 months follow-up was 48% (n = 11) for Non-CFS RF/CTII; 19% (n = 3) for CRYO/CTII; and 7% (n = 1) for CFS RF/ICE3D (P = 0.02). CONCLUSIONS: Non-CFS/CTII was associated with an increased risk of recurrence of the clinical arrhythmia. Ablation with either CFS RF/ICE3D or CRYO/CTII showed high acute success rates and low recurrence rates during follow-up. Cryoablation provided stable contact and was less arrhythmogenic.

Results of Cryoenergy and Radiofrequency-Based Catheter Ablation for Treating Ventricular Arrhythmias Arising From the Papillary Muscles of the Left Ventricle, Guided by Intracardiac Echocardiography and Image Integration.

BACKGROUND: Catheter radiofrequency ablation of ventricular arrhythmias (VAs) arising from the left ventricle's papillary muscles has been associated with inconsistent results. The use of cryoenergy versus radiofrequency has not been compared yet. This study compares outcomes and complications of catheter ablation of VA from the papillary muscles of the left ventricle with either cryoenergy or radiofrequency. METHODS AND RESULTS: Twenty-one patients (40±12 years old; 47% males; median ejection fraction 59±7.3%) with drug refractory premature ventricular contractions or ventricular tachycardia underwent catheter cryoablation or radiofrequency ablation. VAs were localized using 3-dimensional mapping, multidetector computed tomography, and intracardiac echocardiography, with arrhythmia foci being mapped at either the anterolateral papillary muscle or posteromedial papillary muscles of the left ventricle. Focal ablation was performed using an 8-mm cryoablation catheter or a 4-mm open-irrigated radiofrequency catheter, via transmitral approach. Acute success rate was 100% for cryoenergy (n=12) and 78% for radiofrequency (n=9; P=0.08). Catheter stability was achieved in all patients (100%) treated with cryoenergy, and only in 2 (25%) patients treated with radiofrequency (P=0.001). Incidence of multiple VA morphologies was observed in 7 patients treated with radiofrequency (77.7%), whereas none was observed in those treated with cryoenergy (P=0.001). VA recurrence at 6 months follow-up was 0% for cryoablation and 44% for radiofrequency (P=0.03). CONCLUSIONS: Cryoablation was associated with higher success rates and lower recurrence rates than radiofrequency catheter ablation, better catheter stability, and lesser incidence of polymorphic arrhythmias.

Cryoablation for Ventricular Arrhythmias Arising From the Papillary Muscles of the Left Ventricle Guided by Intracardiac Echocardiography and Image Integration.

OBJECTIVES: This case series reports outcomes and complications of catheter cryoablation at the papillary muscles (PM) of the left ventricle (LV). BACKGROUND: Catheter radiofrequency ablation is an effective treatment for ventricular arrhythmias (VAs) arising from the PM of the LV. The use of cryoablation at PMs has not been described. METHODS: Ten patients (70% men; median age: 38 years [range: 34 to 45 years]) with drug-refractory premature ventricular contractions or ventricular tachycardia underwent catheter cryoablation. VAs were localized using 3-dimensional (3D) mapping, multidetector computed tomography, and intracardiac echocardiography, with arrhythmia foci being mapped at either the anterolateral PM or posteromedial papillary muscle (PMPM) of the LV. Focal ablation, up to 240 s with freeze-thaw-freeze cycles was performed using an 8-mm cryoablation catheter via a transmitral approach. RESULTS: Termination of ventricular arrhythmia was observed in all 10 patients during ablation. Median follow-up was 6 months after ablation. The PMPM had higher prevalence of clinical arrhythmias (100% PMPM VAs vs. 10% anterolateral PM VAs). The PM base was the most frequent site of origin of the arrhythmias (60% of patients). Pace-mapping showed ≥11/12 match in all treated PM at the site of effective lesion. All VAs arising from the base of the PM showed Purkinje potentials. There were no post-procedure complications. VA recurred in 1 patient. CONCLUSIONS: Cryoablation for arrhythmias arising from the PMs of the LV can be performed, and is a safe and effective alternative energy source for ablation.

Propafenone versus vernakalant for conversion of recent-onset atrial fibrillation.

INTRODUCTION: An oral loading dose of propafenone 600 mg is used in our center as in other places around the world for conversion of recent-onset atrial fibrillation (AF) in patients without structural heart disease. Vernakalant is a novel, safe, and effective drug used intravenously and has proved to be more rapid in converting recent-onset AF to sinus rhythm compared with placebo and amiodarone. There is no study that compares vernakalant with propafenone. The aim of our study is to compare the time taken for conversion of recent-onset AF in patients treated with vernakalant and propafenone. METHODS: Thirty-six hemodynamically stable patients with recent-onset AF without structural heart disease were prospectively included. A single oral dose of propafenone 600 mg was administered to 19 patients and 17 received intravenous vernakalant. Clinical and laboratory variables, conversion rate, and time to conversion were recorded. RESULTS: Baseline characteristics were similar in both groups. Time to conversion to sinus rhythm was of 166 min (120-300) in the propafenone group versus 9 min (6-18) in the vernakalant group (P = 0.0001). Conversion rate was of 78% in the propafenone group at 8 h and of 93% in the vernakalant group at 2 h; yet, this difference was not statistically significant (P = 0.4). Time to conversion had a direct impact in hospital stay, which was 43% shorter in the vernakalant group (P = 0.0001). CONCLUSION: Time to conversion of AF to sinus rhythm was significantly shorter in the vernakalant group compared with the propafenone group and was associated with shorter hospital stay.

Three-dimensional esophagus reconstruction and monitoring during ablation of atrial fibrillation: combination of two imaging techniques.

OBJECTIVE: The purpose of the study was to determine the accuracy of a novel three-dimensional (3D) imaging integration technique of the esophagus combining multislice computed tomography (CT) scan of the esophagus into the three-dimensional (3D) electroanatomic map just before pulmonary vein (PV) isolation. METHODS: We included 94 consecutive patients with symptomatic atrial fibrillation (AF) who underwent ablation. All patients had a CT performed prior procedure that was integrated to the 3D reconstruction electromechanical map of the atrium and the esophagus (Verismo(TM), EnSite® NavX version 7.0 J, St. Jude Medical Inc.). During the procedure, a quadripolar electrophysiology catheter placed in the esophagus was used for mapping and to monitor esophagus position. Integrated (fusion) images were used to determinate the esophagus position compared to the left atrium posterior wall and its relationship with PV ostiums. We compared esophagus position by CT and fusion images. RESULTS: Procedural success was 97.9% with no fatal complications. Esophagus locations were as follows: left 57%, right 7%, oblique course 11% and central 25%. Agreements in esophageal position between CT and fusion imaging techniques were 83.3% and 64% for patients with a recent (≤48 h) and non-recent CT assessment (>48 h), respectively. Throughout the procedure, esophagus stability was 88.8% (lateral displacement<15 mm). Ablative strategy was modified in 51% of the cases due to awareness of esophagus location. CONCLUSION: Guidance of AF ablation with 3D fusion images was safe and effective. CT images of the esophagus, especially if acquired within 48 h before ablation, ensure appropriate intraprocedural localization of the esophagus.

Predictores de recurrencia y resultados en la ablación de la fibrilación auricular paroxística / Predictors of Recurrence and Outcomes in Catheter Ablation of Paroxysmal Atrial Fibrillation

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Experiencia preliminar de crioablación con catéter balón en fibrilación auricular paroxística: serie de 100 casos / Preliminary Experience with Cryoballoon Ablation in Paroxysmal Atrial Fibrillation: 100-case series

Introducción: La evaluación de nuevas fuentes de energía para el tratamiento de la fibrilación auricular paroxística (FAP) es de gran interés clínico. La crioablación con catéter balón se presenta como una alternativa atractiva para los pacientes con FAP refractaria al tratamiento farmacológico. Objetivos: Describir la experiencia inicial llevada a cabo en nuestra institución desde noviembre de 2013 hasta mayo de 2015 con la utilización de la técnica de crioablación con catéter balón en pacientes con FAP y evaluar la seguridad, la eficacia y las características del procedimiento. Material y métodos: Estudio retrospectivo observacional de un solo centro en el que se examinaron los 100 primeros casos consecutivos realizados con criobalón Arctic Front® de 28 mm (Medtronic, Inc.) desde noviembre de 2013 hasta mayo de 2015. Se definió éxito inmediato al aislamiento de la totalidad de las venas pulmonares. La recurrencia de fibrilación auricular se evaluó en el grupo de 72 pacientes que tuvieron un seguimiento de más de 6 meses. Resultados: La duración del procedimiento fue de 78,03 ± 19,84 minutos con un tiempo de fluoroscopia de 20,79 ± 11,91 minutos y una dosis de radiación total de 202,93 ± 81 mGy La tasa de éxito inmediato fue del 100%. La tasa de complicaciones fue del 1% a raíz de una parálisis diafragmática transitoria. En el seguimiento de los pacientes con más de 6 meses del procedimiento, la tasa libre de fibrilación auricular fue del 81,95%. Conclusiones: Nuestra experiencia inicial con crioablación resultó segura y eficaz, con una tasa de éxito inmediato elevada y una tasa de complicaciones baja. El procedimiento resultó ser de corta duración y la tasa libre de fibrilación auricular en el seguimiento fue más que aceptable.

Background: The evaluation of novel energy sources for the treatment of paroxysmal atrial fibrillation (PAF) is of great clinical interest. Cryoballoon ablation appears as an attractive alternative for patients with PAF refractory to pharmacological therapy Objectives: The purpose of this study was to describe the initial cryoballoon ablation experience performed at our institution from November 2013 to May 2015 in patients with PAF, evaluating the safety, efficacy and characteristics of the procedure. Methods: This was a retrospective, observational study analyzing the first 100 consecutive cases performed with 28-mm Arctic Front™ cryoballoon (Medtronic, Inc.) from November 2013 to May 2015. Immediate success was defined as isolation of all pulmonary veins. Atrial fibrillation recurrence was assessed in 72 patients with more than 6 months follow-up. Results: The procedure lasted 78.03±19.84 min with fluoroscopy duration of 20.79±11.91 min and a total radiation dose of 202.93±81 mGy The rate of acute success was 100%. The complication rate was 1% due to transient diaphragmatic paralysis. The AF-free rate was 81.95% in patients with over 6-months follow-up. Conclusions: Our initial experience with cryoballoon ablation was safe and effective with a high rate of acute success and low rate of complications. The procedure was short and the AF-free rate was more than acceptable.

Aislamiento de las venas pulmonares como tratamiento de la fibrilación auricular / Pulmonary Vein Isolation for Treatment of Atrial Fibrillation / Pulmonary Vein Isolation for Treatment of Atrial Fibrillation

Entre marzo de 2009 y diciembre de 2010 se realizaron en forma consecutiva 94 procedimientos de aislamiento de las venas pulmonares como tratamiento de la fibrilación auricular paroxística y persistente, que constituyen la experiencia inicial del Instituto Cardiovascular de Buenos Aires y cuya casuística actual asciende a aproximadamente 180 por año. Nuestra población estuvo constituida mayoritariamente por hombres, con una edad promedio de 55 años. El 71,9% de la población no tenía antecedentes de enfermedad cardiovascular. La forma de presentación fue paroxística en el 65,3% de los casos, con una historia de arritmia de 7 años en promedio y habiendo cumplido tratamiento con tres fármacos antiarrítmicos diferentes que no incluían betabloqueantes ni bloqueantes cálcicos. El número de episodios de fibrilación auricular fue en promedio de 6 por año. La tasa de éxito durante el procedimiento fue del 97,87%. La tasa de éxito primario a los 12 meses fue del 84,04%, del 88,32% para el grupo sin cardiopatía y del 64,8% para el grupo con cardiopatía. El seguimiento promedio fue de 18 ± 6 meses. En nuestra experiencia, el aislamiento de las venas pulmonares es una modalidad de tratamiento con una aceptable tasa de éxito primario en casos muy selectos.

Between March 2009 and December 2010, 94 consecutive procedures of pulmonary vein isolation were performed for treatment of paroxysmal and persistent atrial fibrillation. These interventions constitute the initial experience of the Instituto Cardiovascular de Buenos Aires, where 260 procedures are currently performed each year. Our population consisted mainly of men with an average age of 55.58 years; 71.9% had no history of cardiovascular disease. Paroxysmal atrial fibrillation occurred in 65.3% of cases over an average of 7 years. All patients had received three different antiarrhythmic agents excluding beta blockers or calcium channel antagonists. The average number of episodes of atrial fibrillation was 6 per year. The success rate during the procedure was 97.87%. The primary success rate at 12 months was 84.04%, 88.32% for the group without heart disease and 64.8% for the group with heart disease. Mean follow-up was 18±6 months. In our experience, pulmonary vein isolation is a treatment strategy for very selective cases with an acceptable primary success rate.

Prueba de adenosina en el síncope de origen desconocido: ¿queda algún espacio para su indicación? / Is There Any Room for Adenosine Test in Syncope of Unknown Origin?

Introducción Algunos pacientes con síncope inexplicado desarrollan distintos grados de bloqueo AV paroxístico con la infusión en bolo de 18 mg de adenosina. Este hallazgo tuvo un valor predictivo positivo bajo en ensayos recientes, aunque su utilización no estuvo normatizada. Objetivo Presentar la experiencia en nuestra institución en el seguimiento de pacientes con un primer episodio de síncope de origen desconocido (SOD) maligno, a quienes se les realizó sistemáticamente una prueba de adenosina. Material y métodos Se incluyeron en forma prospectiva y consecutiva pacientes que presentaban síncope inexplicado con traumatismo grave, sin antecedentes sincopales previos, sin sospecha de etiología vagal, sin cardiopatía orgánica, con estudios neurológicos y cardiológicos normales (incluido tilt test sensibilizado), a los que se les realizó una prueba de adenosina. La prueba se efectuó al final del estudio electrofisiológico. Se infundieron en bolo 18 mg de adenosina por la vena femoral bajo monitorización electrocardiográfica continua; se definió prueba positiva al desarrollo de bloqueo AV completo con pausa mayor de 6 segundos. Resultados Entre 1999 y 2009 se les realizó una prueba de adenosina a 29 pacientes (edad promedio 63 ± 12 años, 17 mujeres). La prueba fue positiva en 17, con una pausa promedio de 10.185± 3.430 mseg. La edad promedio de este grupo fue de 64 ± 13 años, 13 eran mujeres. En los 12 pacientes restantes (59 ± 11 años), la prueba fue negativa, con una pausa promedio de 2.570 ± 1.067 mseg. Todos recibieron recomendaciones higiénico-dietéticas para la prevención del síncope neuromediado y en 9 pacientes con prueba de adenosina positiva se implantó un marcapasos definitivo. El seguimiento fue de 51 ± 37 meses. Sólo 2 pacientes tuvieron recurrencia del síncope, ambos con prueba de adenosina positiva y sin implante de marcapasos. Conclusiones Los pacientes con síncope de origen desconocido y riesgo inicial alto representan en el seguimiento una población de riesgo clínico bajo, con una tasa de recurrencia muy baja, independientemente de la estrategia terapéutica implementada.

Background Few patients with unexplained syncope develop different degrees of paroxysmal AV block after the infusion of 18 mg of adenosine. Recent trials have reported that the positive predictive value of this finding is low; yet the use of the test has not been standardized. Objective To present our experience with follow-up of patients with a first episode of malignant syncope of unknown origin (SUO) who underwent adenosine test. Material and Methods We included patients with unexplained syncope and severe trauma in a consecutive and prospective fashion. None of the patients had a previous history of syncope, and vasovagal syncope was not suspected. Structural heart diseases were ruled out. Neurological and cardiovascular tests were normal (including sensitized TT). All the participants underwent adenosine test after the electrophisiologic study. A bolus of 18 mg of adenosine was administered via the femoral vein under continuous electrocardiographic monitoring. A positive test was defined by the development of complete AV block with pauses longer than 6 seconds. Results Between 1999 and 2009, adenosine test was performed in 29 patients (mean age 63±12 years, 17 were women). The test was positive in 7 patients, and the mean duration of pauses was 10.185±3.430 ms. Mean age in this group was 64±13 years, 13 were women. The test was negative in the remaining 12 patients (59±11 years, mean pauses 2.570±1.067 ms. All patients were received information about hygienic and dietetic measures to prevent neurocardiogenic syncope, and a definite pacemaker was implanted in 9 patients with positive adenosine test. Follow-up was 51±37 months. Syncope recurrence occurred in only 2 patients with positive adenosine test who did not undergo pacemaker implantation. Conclusions Patients with syncope of unknown origin and initial high risk represent a population of low clinical risk during followup, with low recurrence rate regardless of the therapeutic strategy used.

Taquicardia ventricular asociada con la utilización de sibutramina / Ventricular Tachycardia Associated with SibutramineTreatment / Ventricular Tachycardia Associated with Sibutramine- Treatment

La prevalencia de obesidad se encuentra en aumento en las últimas décadas y la importancia que se le da a la imagen corporal lleva a que se utilicen adyuvantes a la dietoterapia para lograr descensos de peso más rápidos y efectivos. Dentro de estas medidas se incluye la sibutramina, un medicamento cuyo mecanismo de acción consiste en la inhibición de la recaptación de serotonina y noradrenalina. Es a través de su acción simpaticomimética que entre sus reacciones adversas presenta efectos a nivel cardiovascular que han llevado a que se recibieran alertas de diversos organismos de control. En esta presentación se describe el caso de una mujer que sufrió episodios de taquicardia ventricular monomorfa luego de iniciar un tratamiento con sibutramina. En el examen con métodos complementarios no se evidenció patología estructural, el estudio electrofisiológico no indujo TV y luego de suspendida la droga no volvió a presentar fenómenos arrítmicos.

The prevalence of obesity is increasing in the last decades. The importance of the body image makes people use adjuvants to diet to reduce weight more quickly and effectively. Sibutramine is a drug that inhibits serotonin and norepinephrine reuptake. The stimulation of the sympathetic nervous system produces adverse effects on the cardiovascular system that have been reported by diverse monitoring agencies. We describe the case of a woman who presented monomorphic ventricular tachycardia after initiating treatment with sibutramine. The complementary tests showed no evidence of structural heart disease and the electrophysiology study did not induce VT. The patient did not present arrhythmias after the drug was discontinued.

El aislamiento de las venas pulmonares como tratamiento de la fibrilación auricular refractaria / Pulmonary vein isolation in patients with refractory atrial fibrillation

Introducción: La fibrilación auricular (FA) es la arritmia sostenida más común. En pacientes seleccionados, se realiza ablaci¢n por cat‚ter a nivel de las venas pulmonares, en donde se genera actividad ect¢pica que la produce. Se presenta la experiencia en el tratamiento de la FA mediante el aislamiento de venas pulmonares en 152 casos consecutivos. Materiales y m‚todos: La población estuvo constituida por 152 pacientes (122 hombres), edad promedio de 55.58 años. El 81.9 por ciento de la población no presentaba cardiopatía estructural. La forma de presentación fue paroxística en el 65.95 por ciento de los casos, con una historia de arritmia de 7 años en promedio, habiendo cumplido tratamiento con 3 fármacos antiarrítmicos diferentes. Se realizó mapeo no fluoroscópico y ablación de la porción antral de cada vena pulmonar, en forma secuencial. Resultados: La tasa de éxito durante el procedimiento fue el 97.87 por ciento. Se presentaron 12 complicaciones, 4 de ellas derrame pericárdico; ninguno requirió cirugía correctiva. El seguimiento promedio fue de 18+6 meses. En 24 horas pacientes se presentó recurrencia de la FA después del tercer mes de seguimiento; es decir, la tasa de éxito global primario a 12 meses fue 84.04 por ciento para el grupo en cardiopatía y del 64.8 para el grupo con cardiopatía. Conclusión: El aislamiento de las venas pulmonares es una modalidad de tratamiento con una aceptable tasa de éxito primario en casos seleccionados.

Introduction: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. In selected patients, catheterablation was performed at the sites of the pulmonary veins where ectopic activity triggers AF. Our experience with AFtreatment by pulmonary vein isolation in 152 consecutive cases is presented and discussed.Methods. Our population consisted mainly of men (122 of 152 patients), with an average age of 55.6 years. Paroxysmal AFwas present in 65.9% of the cases and 81.9% of the population had a structurally normal heart. AF had been present foran average of 7 years. All of the patients fulfilled a treatment period protocol in which three different antiarrhythmic drugswere used first. Nonfluoroscopic mapping and antral pulmonary vein isolation were performed sequentiallyResults. The procedural success rate was 97.9%. There were 12 complications, including 4 pericardial effusions but nonerequired surgical repair. The mean follow-up period was 18±6 months. AF recurred in 24 patients after the third monthof follow-up. There was an 84.04% success rate at 12 months: 88.3% for the group with a normal heart and 64.1% for thegroup with a cardiomyopathy.Conclusion. Isolation of the pulmonary veins can be achieved in appropriately selected cases with AF and has anacceptable rate of success.

El aislamiento de las venas pulmonares como tratamiento de la fibrilación auricular refractaria en un centro de Argentina

Entre marzo de 2009 y marzo de 2011 se realizaron en forma consecutiva 152 intervenciones de aislamiento de venas pulmonares para el tratamiento de la fibrilación auricular (FA) paroxística y persistente, como parte de la experiencia del Instituto Cardiovascular de Buenos Aires (ICBA), cuyo número de procedimientos es de aproximadamente 360 por año. Nuestra población estuvo constituida mayoritariamente por hombres con una edad promedio de 55,58 años; 81,9% de la población no presentaba antecedentes de enfermedad cardiovascular. La forma de presentación fue paroxística en 65,95% de los casos, con una historia de arritmia de siete años en promedio y habiendo cumplido tratamiento con tres fármacos antiarrítmicos diferentes que no incluían betabloqueantes ni bloqueantes cálcicos. El número de episodios de FA fue en promedio de seis por año. La tasa de éxito durante el procedimiento fue de 97,87%. La tasa de éxito global primario a 12 meses fue 84,04%; 88,32% para el grupo sin cardiopatía y 64,8% para el grupo con cardiopatía. El seguimiento promedio fue de 18 ± 6 meses. En nuestra experiencia, el aislamiento de las venas pulmonares es una modalidad de tratamiento con una aceptable tasa de éxito primaria en casos muy selectos.

Between March 2009 and March 2011 we carried out 152 cases of pulmonary veins isolation (PVI), as treatment of the paroxysmal or persistent atrial fibrillation (AF). Our population was constituted mainly by men with an average age of 55,58 years old. The 81,9% of the population presented normal heart. Paroxysmal atrial fibrillation was present in 65,95% of the cases. Atrial fibrillation was present by an average of 7 years. All of them, had fulfilled a treatment with three different antiarrhythmic drugs none of them being beta blockers or calcium channel blockers. The number of episodes of AF was in average 6 per year. The rate of success during the procedure was 97,87%. The primary 12 months success rate was 88,32% for the group with normal heart and 64,08% for the group with cardiomyopathy. In our experience the isolation of the pulmonary veins is an attainable treatment in very select cases with an acceptable rate of success.

Runaway pacemaker: a forgotten phenomenon?

Runaway is an uncommon pacemaker dysfunction, characterized by fast and erratic spikes at non-physiological rates. This infrequent but potentially lethal failure mode may be related to low battery voltage. Four single chamber pacemaker patients were analyzed (Medtronic Minix ST 8330, Minneapolis, MN, had been implanted in two patients and two CPI Triumph VR 1124, St Paul, MN, in the other two). They had been admitted because of presyncopal episodes. Typical high rate stimuli at 2000 ppm alternating with pacing at 60-65 ppm were recorded in all ECGs. Lead system tests were normal. The pulse generators had to be replaced.

Transcranial Doppler monitoring during head upright tilt table testing in patients with suspected neurocardiogenic syncope.

The aim of the present study was to evaluate the mechanism of cerebrovascular autoregulation in patients with neurocardiogenic syncope using bilateral transcranial Doppler (TCD) monitoring during head upright tilt table testing (HUT). Two hundred and six patients were prospectively studied. One hundred and fifty-nine subjects (77%) had a prior history of syncope and 47 (23%) had presyncope. Ninety-nine patients (48%) had syncope or presyncope during HUT with a 76% fall in diastolic middle cerebral artery blood flow velocity (D-MCA-BFV). Systolic MCA-BFV (S-MCA-BFV) fell by 33%. Deepening of the dicrotic notch in the Doppler waveform always preceded the fall in D-MCA-BFV. Patients without syncope or presyncope (n=96) had smaller changes in cerebral blood flow velocities during HUT and only twenty-two subjects had transient deepening of the dicrotic notch. Eleven subjects had presyncope during HUT due to an exaggerated response to nitrates with progressive arterial hypotension without bradycardia and changes during TCD monitoring that were intermediate between positive and negative HUT. In conclusion, patients with neurocardiogenic syncope have changes in cerebral blood flow during the event. TCD monitoring during HUT helps to assess these alterations.

Utilidad de los electrogramas almacenados de marcapasos definitivos para la evaluación de arritmias y decisión de conductas terapéuticas / Usefulness of stored electrograms in patients with permanent pacemakers for the assessment of arrhythmias and therapeutic decision making

Introducción y objetivo: Con el advenimiento de la nueva generación de marcapasos definitivos con capacidad dealmacenamiento de eventos (MPCA) ha surgido una nueva herramienta diagnóstica en el seguimiento de los pacientes. El presente trabajo se realizó con el objetivo de conocer las alteraciones del ritmo en pacientes portadores de MPCA. Material y métodos: En 53 pacientes consecutivos, desde junio de 2002 a enero de 2004, la recolección de electrogramas (EGM) se activó en el momento del implante del marcapasos y se determinóasí la necesidad de alguna intervención terapéutica. El período de seguimiento fue de 8 ± 6 meses; 39 de los marcapasos correspondían a modo DDD y 14 a VDD, todos ellos con recolección de electrogramas activada. Se excluyeron los registros que evidenciaran mal funncionamiento del generador y también aquellos con diagnóstico dudoso por falta del comienzo dela arritmia (onset). Resultados: De los trazados analizados, se detectaron 20 arritmias auriculares sostenidas (fibrilación auricular, 11; taquicardia o aleteo auricular, 9), 3 taquicardias ventriculares sostenidas, 3 TV no sostenidas y 2 taquicardias mediadas por marcapasos. En todas las arritmias encontradasse decidió una intervención terapéutica única o combinada: en 4 se realizó ablación por radiofrecuencia, en 22 se indicó tratamiento farmacológico y en 37, la arritmia requirió la reprogramación del marcapasos.Conclusión: El análisis de los electrogramas almacenados es una herramienta muy útil para evidenciar eventos arrítmicos y decidir conductas terapéuticas.