Taquicardia ventricular por reentrada rama - rama en pacientes con enfermedad de Steinert: serie de tres casos y revisión de la literatura / Bundle branch reentrant ventricular tachycardia in patients with Steinert´s disease: report of three cases and review of the literature

Resumen: Se presentan tres casos clínicos de pacientes con en Enfermedad de Steinert y Taquicardia ventricular recurrente asociada. En los 3 casos el diagnóstico involucró un exhaustivo estudio electrofisiológico que demostró que se trataban de TV rama a rama. Se describen los mecanismos y las maniobras electrofisiológicas para establecer el diagnóstico, como también el tratamiento. Incluye una extensa revisión bibliográfica.

Abstract This is a report of three patients with Steinert´s disease who presented with ventricular tachycardia requiring electrical cardioversion. Extensive electrophysiologic study demonstrated an underlying bundle branch ventricular tachycardia. The mechanisms and the electrophysiological approach to diagnosis are described in detail and the treatment selected is discussed. An extensive review of the literature is included.

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

Clinical research: remote magnetic navigation vs. manually controlled catheter ablation of right ventricular outflow tract arrhythmias: a retrospective study.

Aims: Remote magnetic navigation (RMN) is an alternative to manual catheter control (MCC) radiofrequency ablation of right ventricular outflow tract (RVOT) arrhythmias. The data to support RMN approach is limited. We aimed to investigate the clinical and procedural outcomes in a cohort of patients undergoing RVOT premature ventricular complex/ventricular tachycardia (PVCs/VT) ablation procedures using RMN vs. MCC. Methods and results: Data was collected from two centres. Eighty-nine consecutive RVOT PVCs/VT ablation procedures were performed in 75 patients; RMN: 42 procedures and MCC: 47 procedures. CARTOXPTM or CARTO3 (Biosense Webster) was used for endocardial mapping in 19/42 (45%) in RMN group and 28/47 (60%) in MCC group; EnSiteTM NavXTM (St. Jude Medical) was used in the rest of the cohort. Stereotaxis platform (Stereotaxis Inc., St. Louis, MO, USA) was used for RMN approach. Procedural time was 113 ± 53 min in the RMN group and 115 ± 69 min in MCC (P = 0.90). Total fluoroscopic time was 10.9 ± 5.8 vs. 20.5 ± 13.8 (P < 0.05) and total ablation energy application time 7.0 ± 4.7 vs 11.9 ± 16 (P = 0.67) accordingly. There were two complications in RMN group and five in MCC (P = 0.43). Acute procedural success rate was 80% in RMN vs. 74% in MCC group (P = 0.46). After a median follow-up of 25 months (interquartile range 13-34), the success rate remained 55% in the RMN group and 53% in MCC (P = 0.96). Conclusion: Right ventricular outflow tract arrhythmia ablations were performed using half of fluoroscopic times with Stereotaxis platform RMN compared to manual approach. Acute and chronic success rates as well as complication rates were not significantly different.

Ventricular flutter triggered by fever in a patient with Brugada syndrome.

Brugada syndrome is a clinical-electrocardiographic entity predisposing to malignant ventricular arrhythmias. The typical arrhythmia is polymorphic ventricular tachycardia, which can potentially degenerate to ventricular fibrillation. Monomorphic ventricular tachycardia is uncommon. Our group is reporting the case of a 39-year-old man with known Brugada syndrome who developed ventricular flutter while febrile. Fever has previously been shown to unmask Brugada changes and to induce ventricular arrhythmias. The appearance of monomorphic ventricular tachycardia potentially attributable to sodium-channel dysfunction further confounds the mechanism of arrhythmogenesis in Brugada syndrome. This curious occurrence further underlines the likely complex nature of arrhythmogenesis in Brugada syndrome.

Long-term results of slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia: simple approach.

AIMS: The aim of this study was to report the short- and long-term results of slow pathway radiofrequency (RF) ablation in patients with atrioventricular (AV) nodal reentrant tachycardia (AVNRT) using a simplified approach (2 catheters and short applications of RF). MATERIALS AND METHODS: This was a retrospective study that included consecutive patients with AVNRT. We used an anatomical approach with only 2 catheters. Decremental AV nodal conduction and atrial-His conduction interval jump were measured. To detect the onset of the QRS, we used surface lead II. During the stimulation protocol, we performed S2-QRS and S3-QRS measurements. An increase in the S3-QRS3 interval of 50 milliseconds or greater in response to a decrease in the S2-QRS2 coupling interval of 10 milliseconds was defined as a discontinuous AV nodal function curve and taken as evidence of dual antegrade AV pathways. Atrioventricular nodal reentrant tachycardia was demonstrated by the presence of dual AV nodal physiology, atrial echoes, and tachycardia induction with a 1:1 AV relationship and a VA interval of less than 70 milliseconds. Short RF applications (10-15 seconds) were delivered at an intermediate point between the posteroseptal and medioseptal regions of the Koch triangle. The applications were considered effective when junctional rhythm appeared. The end point was the demonstration of slow pathway modification without AVNRT induction. RESULTS: Three hundred forty-four patients (age, 49.22 ± 17.47 years; 254 were female) were included. Discontinuous AV nodal function curves were found in 271 patients (78.77%), and short-term success was achieved in all patients. The anterograde jump in AV nodal conduction was abolished after RF in 222 patients (81.91%), and discontinuous AV nodal conduction and single AV nodal echo beats persisted in 49 cases (18%). The mean number of RF application was 7.79 ± 2.23, the mean number of effective applications was 4.63 ± 0.62, and the mean RF application time was 54.92 ± 8.03 seconds. The total procedure and fluoroscopy time was 29.45 ± 9.6 and 10.87 ± 2.36 minutes, respectively. After the procedure, all patients were followed up for a mean of 46.44 ± 18.89 months, and 7 patients (2%) presented AVNRT recurrences. Complications were observed in 4 patients (1.16%); no permanent AV block was observed. CONCLUSION: In this study, slow pathway RF ablation using a simplified approach technique is an effective and safe approach for the treatment of AVNRT.

[Is the head-up tilt-test necessary in patients whit clinical diagnosis of vasovagal syncope? Results using a non-sensitized protocol]. / ¿Es necesaria la prueba de inclinación en pacientes con diagnóstico clínico de síncope vasovagal? Resultados utilizando un protocolo no sensibilizado.

INTRODUCTION: Tilt table testing is a simple, non-invasive, low risk test. A not sensitized protocol has been presented in order to shorten the duration of the test. OBJECTIVE: To determine the usefulness of a not sensitized tilt table testing and to compare the results with the pre-test probability, given by the Calgary's score. METHODS: We included patients≥15 years-old with syncope or presyncope with high probability pretest for a vasovagal origin, using the Calgary' score. RESULTS: Seventy patients were analyzed; age 39±20 years old, 66% female. More than 94% of the patients presented a score≥-1, but only 30% of the tilt tests were positive. A score≥-2 was not associated with the result of tilt test. Most of the patients presented a score of 1 (52) and 2 (11), resulting in positive tilt test 32% y 9%, respectively. Among patients with low pre-test probability there was a greater number of negative results (100% with a score of -2 and 50% with score of -5). CONCLUSIONS: This study showed that in patients with vasovagal syncope suggested by clinical assessment, a not sensitized tilt test did not provide additional information, with a significant number of false negatives.

¿Es necesaria la prueba de inclinación en pacientes con diagnóstico clínico de síncope vasovagal?: Resultados utilizando un protocolo no sensibilizado / Is the head-up tilt-test necessary in patients whit clinical diagnosis of vasovagal syncope?: Results using a non-sensitized protocol

Introducción:La prueba de inclinación es un estudio no invasivo, sencillo y de bajo riesgo, donde la utilización de protocolos no sensibilizados sirven para acortar los tiempos de la prueba. Objetivo:Determinar en pacientes con síncope la utilidad de la prueba de inclinación no sensibilizada con fármacos y comparar los resultados con la probabilidad clínica pre-test. Métodos:Se incluyeron pacientes >15 años de edad, con síncope o presíncope, con clínica sugestiva de origen vasovagal, utilizando la escala de Calgary. Resultados:Se analizaron 70 pacientes; edad: 39 ± 20 años, 66% mujeres. De los pacientes, 94% presentó una puntuación >-1, pero sólo 30% de las pruebas fueron positivas. Una puntuación >-2 no se asoció con el resultado de la prueba. La mayoría de los pacientes presentaron una puntuación de 1 (52) y 2 (11), resultando en una prueba positiva en 32% y 9%, respectivamente. En pacientes con probabilidad pre-test baja, hubo mayor número de pruebas negativas (100% con una puntuación de -2 y 50% con puntuación de -5). Conclusiones:El estudio mostró que en pacientes con síncope vasovagal, sugerido por la evaluación clínica, la prueba de inclinación no sensibilizada no proporcionó información adicional, con un número significativo de falsos negativos.

Introduction:Tilt table testing is a simple, non-invasive, low risk test. A not sensitized protocol has been presented in order to shorten the duration of the test. Objective:To determine the usefulness of a not sensitized tilt table testing and to compare the results with the pre-test probability, given by the Calgary's score. Methods:We included patients >15 years-old with syncope or presyncope with high probability pretest for a vasovagal origin, using the Calgary' score. Results:Seventy patients were analyzed; age 39 ± 20 years old, 66% female. More than 94% of the patients presented a score >-1, but only 30% of the tilt tests were positive. A score >-2 was not associated with the result of tilt test. Most of the patients presented a score of 1 (52) and 2 (11), resulting in positive tilt test 32% y 9%, respectively. Among patients with low pre-test probability there was a greater number of negative results (100% with a score of -2 and 50% with score of -5). Conclusions: This study showed that in patients with vasovagal syncope suggested by clinical assessment, a not sensitized tilt test did not provide additional information, with a significant number of false negatives.

Progressive conduction disturbance in myotonic dystrophy.

Myotonic dystrophy (DM), the commonest dystrophy in adults, is an autosomal dominant disease characterized by a variety of multisystemic features. Two main genetically distinct forms of DM have been identified: type 1 (DM1), the classic form first described by Steinert, and type 2 (DM2), identified by Ricker. DM1 is caused by trinucleotide expansion of cytosine- -thymine-guanine (CTG) in the myotonic dystrophy protein kinase gene, whereas in DM2 the expansion of tetranucleotide repeats (CCTG) in the zinc finger protein 9 gene was identified. Both mutations are dynamic and are located in non-coding parts of the genes. Phenotype variability of DM1 and DM2 is caused by a molecular mechanism due to mutated RNA toxicity. DM1 is characterized by myotonia and multi-organ damage with major cardiac involvement. The disease is usually slowly progressive and life expectancy is reduced by the increased mortality associated with cardiopulmonary complications. Sudden death can occur as a consequence of cardiac-conduction abnormalities. We present the ECG of a 26 year-old male with DM1 and progressive conduction system disturbance characterized by syncopal episodes.

[Atrial fibrillation prevalence and treatment with oral anticoagulation in patients with permanent pacemakers]. / Frecuencia de fibrilación auricular y tratamiento con anticoagulantes orales en pacientes con marcapasos definitivo.

Atrial Fibrillation (AF) is the most important risk factor for stroke and thromboembolic events (TE). The aims of this study were to determine the prevalence of AF among patients with permanent pacemakers (PPM), the percentage of anticoagulated patients and the prevalence on TE in this population. The secondary purpose was to determine the "level of knowledge" about indications of anticoagulation for AF patients. This was a descriptive and retrospective study on a consecutive series of patients referred for PPM implantation. Cardiovascular risk factors, indications for pacing, prior history of AF, TE and anticoagulation indication were analyzed. In order to determine possible causes for not indicating anticoagulation, an electronic survey was sent to all doctors that usually refer patients for PPM implant and follow-up to our clinic. Among 934 patients, 26% (244) presented AF of which 34% were anticoagulated. 77.3% presented a CHADS2 score of > or = 2 while only 2% had absolute contraindication for anticoagulation. The prevalence of TE was 9%. More than 60% of the doctors answered the survey. More than 40% acknowledged the CHADS, score but only 33% were able to recognize all variables included in the score and 23% were able to determine when to indicate anticoagulation properly. A low anticoagulation rate was detected among patients with AF and PPM with a high prevalence of TE and stroke. An extremely low adherence to international guidelines was detected among doctors that usually deal with this sort of patients.

Frecuencia de fibrilación auricular y tratamiento con anticoagulantes orales en pacientes con marcapasos definitivo / Atrial fibrillation prevalence and treatment with oral anticoagulation in patients with permanent pacemakers

La fibrilación auricular (FA) es el factor de riesgo más importante para eventos tromboembólicos (ETE). El objetivo del presente estudio fue determinar la prevalencia de FA en pacientes con marcapasos definitivo (MCD), el porcentaje de anticoagulación y la prevalencia de ETE. El objetivo secundario fue determinar el nivel de conocimiento relacionado con las indicaciones de anticoagulación oral (AO) en pacientes con FA. Estudio descriptivo y retrospectivo de una serie consecutiva de pacientes. Se evaluaron factores de riesgo cardiovascular, motivos de indicación del MCD, antecedentes de FA, ETE y régimen de anticoagulación. Para determinar las potenciales causas de no AO, se realizó una encuesta a todos los médicos que habitualmente derivan sus pacientes a nuestro servicio. De 934 pacientes, el 26% (244) presentó FA, con una tasa de AO del 34%. El 77,3% presentaban un score CHADS2 ³2, solo el 2% presentó contraindicaciones para AO y la prevalencia de ETE fue del 9%. El 63% de los médicos contestó la encuesta. El 41% conocían el score CHADS2, el 33% pudo describir los parámetros clínicos que evalúa y un 23% respondieron correctamente el puntaje necesario para indicar AO. Se detectó una baja tasa de anticoagulación oral en pacientes con FA y MCD, con una elevada prevalencia de ETE y un sorprendente desconocimiento por parte de los médicos tratantes de las recomendaciones actuales de tratamiento.

Atrial Fibrillation (AF) is the most important risk factor for stroke and thromboembolic events (TE). The aims of this study were to determine the prevalence of AF among patients with permanent pacemakers (PPM), the percentage of anticoagulated patients and the prevalence on TE in this population. The secondary purpose was to determine the “level of knowledge” about indications of anticoagulation for AF patients. This was a descriptive and retrospective study on a consecutive series of patients referred for PPM implantation. Cardiovascular risk factors, indications for pacing, prior history of AF, TE and anticoagulation indication were analyzed. In order to determine possible causes for not indicating anticoagulation, an electronic survey was sent to all doctors that usually refer patients for PPM implant and follow-up to our clinic. Among 934 patients, 26% (244) presented AF of which 34% were anticoagulated. 77, 3% presented a CHADS2 score of ³2 while only 2% had absolute contraindication for anticoagulation. The prevalence of TE was 9%. More than 60% of the doctors answered the survey. More than 40% acknowledged the CHADS2 score but only 33% were able to recognize all variables included in the score and 23% were able to determine when to indicate anticoagulation properly. A low anticoagulation rate was detected among patients with AF and PPM with a high prevalence of TE and stroke. An extremely low adherence to international guidelines was detected among doctors that usually deal with this sort of patients.

Proarrhythmia Induced by Propafenone: What is the Mechanism?

Propafenone, a Class IC antiarrhythmic drug, is an orally active sodium channel-blocking agent. It is effective in supraventricular tachyarrhythmias and is particularly useful in converting atrial fibrillation to sinus rhythm. In therapeutic doses, it may cause non-cardiac and cardiac toxicity, including proarrhythmia.