Xavier Viñolas Prat

Guías de práctica clínica de la Sociedad Española de Cardiología en arritmias cardíacas

Se presentan las conclusiones consensuadas de un panel de arritmologos, convocados por la Sociedad Espanola de Cardiologia, acerca del enfoque terapeutico de las arritmias cardiacas. El manuscrito se ha dividido en 7 secciones, que representan areas de afinidad en cuanto a terapeutica: 1. Taquicardias supraventriculares no asociadas al sindrome de Wolff-Parkinson-White. 2. Sindromes de preexcitacion. 3. Fluter auricular. 4. Fibrilacion auricular. 5. Arritmias ventriculares no sostenidas. 6. Taquicardias ventriculares sostenidas (en ausenciade sindrome de parada cardiaca). 7. Sindrome de parada cardiaca por taquiarritmia ventricular. En cada una de las secciones se emiten recomendaciones en cuanto a las distintas opciones terapeuticas, farmacologicas y no farmacologicas, asi como en cuanto a los subgrupos de pacientes subsidiarios de cada una de ellas.

A new method of filtering T waves to detect hidden P waves in electrocardiogram signals

AIMS A correct identification of the P wave is crucial for the diagnosis of narrow QRS tachycardias. This is sometimes difficult because atrial activity is hidden in the T wave. The aim of this study is to evaluate the usefulness of a T wave filtering technique based on wavelet transformation to identify atrial activity. METHODS AND RESULTS Forty-two patients with narrow QRS tachycardias and regular atrial activity were studied. A surface electrocardiogram (ECG), intra-atrial recording, and the T wave filtering ECG were compared simultaneously to check the accuracy of the filtering system in detecting atrial activity. The sensitivity of the T wave filtering and P wave detection algorithm was 85.8% [95% confidence interval (CI): 81.2-89.4%] and the specificity was 89.4% (95% CI: 87.1-91.4%), with a global accuracy of 88.5% (95% CI: 86.5-90.3%). The expert cardiologists accuracy in distinguishing between atrioventricular nodal reentry tachycardia and atrioventricular reentry tachycardia was 75% in the surface ECG vs. 100% in the ECG with the T wave filtering process (P<0.01). CONCLUSIONS T wave filtering based on wavelet transformation improves the capacity of the surface ECG to identify atrial activity in cases of regular narrow QRS supraventricular tachycardias.

Pulmonary vein isolation in cases of difficult catheter placement: A new pacing maneuver to demonstrate complete isolation of the veins

BACKGROUND Pulmonary vein electrical isolation is the main goal of atrial fibrillation ablation. To ensure electrical isolation of the pulmonary veins, entrance and exit block should be demonstrated. However, this is sometimes challenging due to the complex anatomy of the pulmonary vein area and the anatomical variations that may preclude the correct position of the commonly used circular multielectrode catheter inside the veins. OBJECTIVE To describe a new pacing maneuver useful to demonstrate complete isolation of ipsilateral veins in cases of difficult catheter placement. METHODS Three representative cases illustrate the usefulness of the maneuver either at the right or left pulmonary veins. RESULTS After the circumferential ablation of ipsilateral veins, the circular catheter is positioned in one vein and the ablation catheter in the other ipsilateral vein. When local capture in one vein can be demonstrated while pacing from the other vein and no conduction to the atria is observed, isolation of both veins can be assured. CONCLUSION This novel maneuver might be of help in assessing complete isolation of the pulmonary veins in cases of difficult circular catheter placement.

Flúter auricular típico en corazón trasplantado

El flúter auricular es la arritmia más frecuente en los pacientes sometidos a trasplante cardíaco ortotópico. Se presenta un caso representativo de un flúter auricular típico con rotación antihoraria alrededor del anillo tricuspídeo en una paciente sometida a trasplante cardíaco ortotópico 13 años antes. El mapa de activación de la arritmia (fig. 1) muestra el encuentro entre las zonas más precoces y más tardías característico de las macrorreentradas. Se representó como «escara» (en gris) la zona correspondiente a la aurícula receptora, que presentaba una taquisistolia auricular con longitud de ciclo ligeramente más lenta que la del flúter y sin relación con IMÁGENES EN CARDIOLOGÍA

Identification of the critical isthmus of a reentrant ventricular tachycardia at a glance

A 61-year-old male with prior inferior myocardial infarction was referred for catheter ablation of a monomorphic ventricular tachycardia (VT). His left ventricular ejection fraction was 45% and a cardiac magnetic resonance showed late gadolinium enhancement at the inferobasal left ventricle. Detailed endocardialmapping of the left ventricle was performed during sinus rhythm, using the multielectrode catheter Pentaray and the CARTO 3 mapping system (Biosense Webster, Inc., Diamond Bar, CA, USA). A low-voltage area (<1.5 mV) was identified at the inferobasal left ventricle. During VT, tiny diastolic potentials were recorded along the entirely VT cycle length at the septal border of the scar (Figure 1A and B). Following the sequence of activation of the diastolic potentials recorded by the multipolar catheter, we were able to reconstruct the activation along the critical isthmus of the VT that was confirmed by entrainment maneuvers. Interestingly, spontaneous termination of the VT showed that most of the diastolic potentials recorded during VT were canceled by the ventricular electrogram during sinus rhythm at the same location, and therefore, difficult to identify by voltage criteria. This emphasizes how the configuration of the recorded electrograms is influenced by the wave front activation and suggests that at least part or the isthmuswas functional. Pacing during sinus rhythm from different poles of the Pentaray catheter identified nonexcitable tissue in close proximity to the critical isthmus, leading to a better delimitation of the substrate involved in the VT circuit. Radiofrequency applications across the isthmus terminatedVTand rendered the tachycardia not inducible. The case illustrates the potential of the simultaneous recording from multiple small electrodes in improving our understanding of the VT substrate.

Updated performance of the Micra transcatheter pacemaker in the real-world setting: A comparison to the investigational study and a transvenous historical control

BACKGROUND Early results of the Micra Investigational Device Exemption (IDE) study and Micra Post-Approval Registry (PAR) demonstrated excellent safety and efficacy performance; however, intermediate-term results across a large patient population in the real-world setting have not been evaluated. OBJECTIVES We report updated performance of the Micra transcatheter pacemaker from a worldwide PAR and compare it with the IDE study as well as a transvenous historical control. METHODS The safety objective of the analysis was system- or procedure-related major complications through 12 months postimplantation. We compared the major complication rate with that of the 726 patients from the IDE and with a reference data set of 2667 patients with transvenous pacemakers by using a Fine-Gray competing risk model. RESULTS The Micra device was successfully implanted in 1801 of 1817 patients (99.1%). The mean follow-up period was 6.8 ± 6.9 months. Through 12 months, the major complication rate was 2.7% (95% confidence interval [CI] 2.0%-3.7%). The risk of major complications for Micra PAR patients was 63% lower than that for patients with transvenous pacemakers through 12 months postimplantation (hazard ratio 0.37; 95% CI 0.27-0.52; P < .001). The major complication rate trended lower in the PAR than in the IDE study (hazard ratio 0.71; 95% CI 0.44-1.1; P = .160), driven by the lower pericardial effusion rate in the PAR. There were 3 cases of infection associated with the procedure, but none required device removal and there were no battery or telemetry issues. Pacing thresholds were low and stable through 12 months postimplantation. CONCLUSION Performance of the Micra transcatheter pacemaker in international clinical practice remains consistent with previously reported data. Major complications were infrequent and occurred 63% less often compared to transvenous systems. CLINICAL TRIAL REGISTRATION Micra Transcatheter Pacing System Post-Approval Registry ClinicalTrials.gov identifier: NCT02536118; Micra Transcatheter Pacing Study ClinicalTrials.gov identifier: NCT02004873.

Imagen de seudocaptura por microdesplazamiento del electrodo en un marcapasos VDD

Los nuevos marcapasos secuenciales auriculoventriculares(AV) han mejorado la individualizacionen el modo de estimulacion para cada paciente. Lacomplejidad de los sistemas hace en ocasiones dificildetectar algunas malfunciones. En el caso clinicoque presentamos se expone como un fallo decaptura por microdesplazamiento del electrodopuede pasar desapercibido en un control sencillode marcapasos, al unirse varios factores como presentarconduccion AV normal en ese momento, laconcordancia entre la espicula y el QRS conducidoy la similar morfologia entre el complejo QRS conducidoy el estimulado.