Utility and feasibility of the CartoUnivu™ system for atrial flutter ablation in patients with mechanical prosthetic valves.

Ablation of macroreentrant atrial tachycardia in patients with mechanical prosthetic valves represents a challenge for electrophysiologists, because of the complexity of the procedure and the potential complications. Moreover, the need for fluoroscopy in this type of procedure is greater, due to the risk of interference between the prosthetic valve and the ablation or mapping catheter. We present two cases of patients with mechanical prosthetic valves and atrial flutter who underwent successful ablation with no complications using the CartoUnivu™ tool, which integrates the electroanatomical map and the fluoroscopy image.

Effect of pulmonary vein catheter ablation on kidney function in patients with atrial fibrillation. A prospective cohort study.

INTRODUCTION AND OBJECTIVES: Several studies have linked the presence of atrial fibrillation (AF) with reduced estimated glomerular filtration rate (eGFR). Our objective was to compare changes in eGFR in patients with AF after pulmonary vein (PV) ablation depending on the success of the technique, as well as to examine the relationship between eGFR and several biomarkers. METHODS: Prospective cohort of patients with AF referred to our center for PV ablation with a 1-year follow-up. We estimated eGFR using the Chronic Kidney Disease Epidemiology Collaboration formula at baseline and at 3 and 12 months. Biomarkers (B-type natriuretic peptide, corin, and galectin-3) were measured before ablation and at 12 months. RESULTS: We studied 124 patients (age 55±10 years, 69.4% men). Seventy-five had paroxysmal AF (60.5%). The mean baseline eGFR was 90.8 [77.8-100.0] mL/min/1.73 m2. The eGFR increased at the end of follow-up, with a statistically significant difference between patients with recurrence at 12 months and those without (-1.1 [-6.0 to 8.8] mL/min/1.73 m2 vs 7.1 [-0.6 to 14.2] mL/min/1.73 m2, P=.017). The improvement in eGFR at 12 months was inversely proportional to baseline eGFR. B-type natriuretic peptide and corin levels improved at 12 months, while galectin-3 levels worsened, which was unrelated to eGFR. CONCLUSIONS: In patients with AF treated with PV ablation, an overall improvement in eGFR was observed, which was more marked in the subgroup without recurrences, although without significant differences on multivariate analysis.

Efecto de la cardioversión eléctrica programada de fibrilación auricular sobre la función renal / Effect of programmed electrical cardioversion of atrial fibrillation on renal function

Resumen Introducción: Estudios previos han relacionado la presencia de fibrilación auricular (FA) con una tasa de filtrado glomerular estimada (TFGe) reducida. Objetivo: comparar la evolución de la TFGe en pacientes con FA persistente tras cardioversión eléctrica (CVE) programada en función de la existencia o no de recurrencias, así como la evolución de varios biomarcadores. Materiales y métodos: Cohorte prospectiva de pacientes con FA persistente remitidos a nuestro centro para CVE programada con seguimiento de un año. La TFGe se obtuvo mediante la fórmula CKD-EPI en el momento basal y a los 3 y 12 meses. Se midieron biomarcadores antes de la CVE y a los 12 meses. Resultados: Se incluyeron 92 pacientes con FA persistente, edad media de 64 ± 11 años. Al año de seguimiento y en el total de pacientes, la TFGe se redujo de 86,5 [74,6-97,6 a 84,5 [71,7-95,1 ml/min/1,73 m2 (p = 0,002) y la creatinina aumentó de 0,80 [0,72-0,94] mg/dl a 0,83 [0,74-0,97] mg/dl (p = 0,005). La TFGe se redujo al final del seguimiento, sin diferencia estadísticamente significativa entre los pacientes que presentaron recurrencia a los 12 meses y los que no. Las cifras de BNP y corina mejoraron a los 12 meses, mientras que las de galectina-3 no cambiaron, sin relación con la TFGe. Conclusiones: En los pacientes con FA persistente tratados con CVE programada se observó un empeoramiento de la TFGe al año de seguimiento. Los niveles de BNP y corina mejoraron al año de seguimiento. No hubo diferencias en los niveles de galectina-3.

Abstract Introduction: Previous studies have linked the presence of atrial fibrillation (AF) with a reduced estimated glomerular filtration rate (eGFR). Objective: to compare the evolution of eGFR in patients with persistent AF after elective electrical cardioversion (ECV) based on the existence or not of recurrences, as well as the evolution of various biomarkers. Materials and methods: Prospective cohort of patients with persistent AF referred to our center for elective EVC with a 1-year follow-up. The eGFR was obtained using the CKD-EPI formula at baseline and at 3 and 12 months. Biomarkers were measured before ECV and at 12 months. Results: 92 patients with persistent AF were included, mean age 64 ± 11 years. At one year of follow-up and in all patients, the eGFR decreased from 86.5 [74.6-97.6 to 84.5 [71.7-95.1 ml/min/1.73 m2 (p = 0.002) and creatinine increased from 0.80 [0.72-0.94] mg/dl to 0.83 [0.74-0.97] mg/dl (p = 0.005). The eGFR was reduced at the end of the follow-up, with no statistically significant difference between the patients who had recurrence at 12 months and those who did not. BNP and corin levels improved at 12 months, while galectin-3 did not change, unrelated to eGFR. Conclusions: In patients with persistent AF treated with elective ECV, a worsening of eGFR was observed at one year of follow-up. BNP and corin levels improve at one year of follow-up, there were no differences in galectin-3 levels.

[Spanish Catheter Ablation Registry. Fifth official report of the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias (2005)]. / Registro Español de Ablación con Catéter. V Informe Oficial de la Sección de Electrofisiología y Arritmias de la Sociedad Española de Cardiología (2005).

INTRODUCTION AND OBJECTIVES: The findings (i.e., success and complication rates) of the 2005 Spanish Catheter Ablation Registry, as prepared by the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias, are presented. METHODS: As in previous years, data were collected in two ways: retrospectively using a standardized questionnaire sent to electrophysiology laboratories by the Working Group on Electrophysiology and Arrhythmias, and prospectively from a central database. Each participating center selected its own preferred method of data collection. RESULTS: Forty-seven centers contributed data to the registry. A total of 6162 ablation procedures were analyzed, averaging 131 (88) per center. As in previous reports, the three main conditions treated were atrioventricular nodal reentrant tachycardia (n=1795, 29%), accessory pathways (n=1591, 26%), and typical atrial flutter (n=1378, 22%). Atrial fibrillation was the fourth most common condition treated (n=480, 8%). The overall success rate was 93%, major complications occurred in 1.05%, and the mortality rate was 0.03%. CONCLUSIONS: With more than 6000 ablation procedures recorded and with the participation of a greater number of centers throughout the country, the Spanish Catheter Ablation Registry is becoming increasingly representative and is consolidating its value as a point of reference. The number of catheter ablations carried out for atrial fibrillation in Spain is continuing to grow.

[Spanish catheter ablation registry. Fourth official report of the spanish society of cardiology working group on electrophysiology and arrhythmias (2004)]. / Registro Español de Ablación con Catéter. IV Informe Oficial de la Sección de Electrofisiología y Arritmias de la Sociedad Española de Cardiología (2004).

INTRODUCTION: This article details the findings (i.e., success and complication rates) of the 2004 Spanish Catheter Ablation Registry, which was established by the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias. This is the fourth consecutive annual report. MATERIAL AND METHOD: Similar to last year, data were collected in two ways: retrospectively using a standard questionnaire, and prospectively using a central database containing details of each ablation procedure. Each center was asked to participate by selecting one of these methods. RESULTS: Thirty-six centers contributed voluntarily to the registry. Overall, 4147 ablation procedures were reported, giving a mean of 115 [66] procedures per center. The three main conditions treated were AV node reentry tachycardia (32%), the presence of accessory pathways (25%), and common atrial flutter (23%). Success rates were 98%, 89% and 91%, respectively. The overall success rate was 90%, with a major complication rate of 1.4% and a mortality rate of 0.07%. CONCLUSIONS: Although the participation rate was slightly lower than in previous years, the comparability of data collected on a substantial number of ablation procedures (more than 4000) with earlier registry data confirm the validity and consistency of the register.

[Spanish Registry on Catheter Ablation. Second official report of the Working Group on Electrophysiology and Arrhythmias of the Spanish Society of Cardiology (2002)]. / Registro Español de Ablación con Catéter. II Informe Oficial de la Sección de Electrofisiología y Arritmias de la Sociedad Española de Cardiología (2002).

INTRODUCTION AND OBJECTIVES: We present the results (success rates and complication rates) for the second consecutive year of the 2002-Spanish Catheter Ablation Registry, developed by the Spanish Society of Cardiology. MATERIAL AND METHOD: Data were collected retrospectively by questionnaires sent to all interventional cardiology laboratories in Spain. The outcomes and complications of ablation procedures performed during 2002 were classified according to the substrate or mechanism of arrhythmia treated. RESULTS: Forty-three centers voluntarily submitted completed questionnaires. The number of procedures analyzed was 4970, performed at 42 centers, for a mean of 118 78 procedures per center. Global outcome rates were success in 93%, major complications in 1.2%, and death in 0.04% of the patients. The three main substrates treated were AV nodal reentry (29%), accessory pathways (28%) and common atrial flutter (24%). CONCLUSIONS: The 2002 Spanish National Catheter Ablation Registry reports the activity of the majority (90%) of interventional cardiology laboratories in Spain. The efficacy of catheter ablation procedures in Spain is high, and the complication and mortality rates are low.

[Spanish Registry of Catheter Ablation. Third Official Report of the Working Group on Electrophysiology and Arrhythmias of the Spanish Society of Cardiology (2003)]. / Registro Español de Ablación con Catéter. III Informe Oficial de la Sección de Electrofisiología y Arritmias de la Sociedad Española de Cardiología (2003).

INTRODUCTION: The results of the Third Spanish Catheter Ablation Registry, developed by the Working Group on Electrophysiology and Arrhythmias, are presented for the third consecutive year (2003). MATERIAL AND METHOD: In contrast to previous years, data were collected in two different ways at the discretion of the participating center. Retrospective were obtained with a standard questionnaire, as in previous years. Prospective data were obtained from a database of records completed after each ablation was performed. Results and complications are presented according to different arrhythmic substrates. RESULTS: Thirty-nine centers participated in the registry (25 supplied prospective data and 14 retrospective data), representing more than 80% of all electrophysiological laboratories in Spain. A total number of 4354 ablations were recorded (111 procedures per center, 2723 from the prospective registry and 1631 from the retrospective one). The substrate most frequently treated was AV nodal reentry tachycardia (31.6%, 98% success), followed by accessory pathways (26%, 89% success) and atrial macro-reentry tachycardia (23%, 90% success). The incidence of complications was 1.7% and mortality was 0.11%. With the prospective registry we obtained more comprehensive information individualized for each procedure (age, sex, underlying cardiomyopathy, anticoagulation, sedation, type of catheter, etc.). CONCLUSIONS: The high rate of participation in the registry and the consistency of the results with previous years help to consolidate the registry as a reference for the rest of the scientific community. The results from the prospective registry showed better-quality information and more detailed reporting of results and complications.

Functional characterization of a novel frameshift mutation in the C-terminus of the Nav1.5 channel underlying a Brugada syndrome with variable expression in a Spanish family.

INTRODUCTION: We functionally analyzed a frameshift mutation in the SCN5A gene encoding cardiac Na(+) channels (Nav1.5) found in a proband with repeated episodes of ventricular fibrillation who presented bradycardia and paroxysmal atrial fibrillation. Seven relatives also carry the mutation and showed a Brugada syndrome with an incomplete and variable expression. The mutation (p.D1816VfsX7) resulted in a severe truncation (201 residues) of the Nav1.5 C-terminus. METHODS AND RESULTS: Wild-type (WT) and mutated Nav1.5 channels together with hNavß1 were expressed in CHO cells and currents were recorded at room temperature using the whole-cell patch-clamp. Expression of p.D1816VfsX7 alone resulted in a marked reduction (≈90%) in peak Na(+) current density compared with WT channels. Peak current density generated by p.D1816VfsX7+WT was ≈50% of that generated by WT channels. p.D1816VfsX7 positively shifted activation and inactivation curves, leading to a significant reduction of the window current. The mutation accelerated current activation and reactivation kinetics and increased the fraction of channels developing slow inactivation with prolonged depolarizations. However, late INa was not modified by the mutation. p.D1816VfsX7 produced a marked reduction of channel trafficking toward the membrane that was not restored by decreasing incubation temperature during cell culture or by incubation with 300 µM mexiletine and 5 mM 4-phenylbutirate. CONCLUSION: Despite a severe truncation of the C-terminus, the resulting mutated channels generate currents, albeit with reduced amplitude and altered biophysical properties, confirming the key role of the C-terminal domain in the expression and function of the cardiac Na(+) channel.

Genetic testing of patients with long QT syndrome.

Congenital long QT syndrome is mainly caused by mutations in the KCNQ1, KCNH2 and SCN5A genes. The aim of this study was to investigate the prevalence of mutations in these three genes in patients with long QT syndrome or idiopathic ventricular fibrillation seen at our center. The study included nine patients with long QT syndrome and four with idiopathic ventricular fibrillation. The first-degree relatives of genotype-positive probands were also investigated. Missense mutations were found in seven patients with long QT syndrome and two with idiopathic ventricular fibrillation. Overall, 71.4% of mutations were in KCNH2 and 28.6% were in SCN5A. No mutations in KCNQ1 were found. Only two mutations had been previously observed. Mutations were also found in six of the 19 relatives studied. In conclusion, our initial experience shows that genetic testing had a high sensitivity for diagnosing long QT syndrome. Mutations were found most frequently in the KCNH2 gene.

Síndrome de QT largo secundario a hipocalcemia / Long - QT Syndrome Secondary to Hypocalcemia

El síndrome de QT largo es causa de muerte súbita por arritmias ventriculares y puede ser de origen congénito o adquirido. Entre las causas adquiridas, las más frecuentes son los trastornos iónicos y los fármacos. En esta presentación se describe el caso de una paciente con síndrome de QT largo secundario a hipocalcemia por hipoparatiroidismo primario. Es indispensable la detección de posibles causas secundarias y reversibles de síndrome de QT largo, que son más frecuentes que el origen genético, dado que tienen tratamiento etiológico eficaz y se evitan medidas diagnósticas y terapéuticas innecesarias.

Long-QT syndrome is a congenital or acquired disorder that produces sudden death due to ventricular arrhythmias. Electrolyte disturbances and medications are the most common causes of acquired long-QT syndrome. We describe the case of a patient with long-QT syndrome secondary to hypocalcemia caused by primary hypoparathyroidism. The secondary causes of long-QT syndrome should be thoroughly examined as they are more common than the genetic causes. Also, as they are reversible with adequate etiological treatment, their correct identification avoids unnecessary diagnostic and therapeutic measures.