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The coronavirus disease 2019 (COVID-19) pandemic has resulted in a deep restructuring of cardiovascular care, especially in the setting of cardiac arrhythmia units, which are characterized by a wide variety of clinical and interventional activities. We describe the experience of a large university hospital deeply hit during the COVID-19 health crisis (first outbreak of the pandemic), focusing on the exceptional measures implemented and their impact in terms of outcomes. We performed a retrospective study comparing the human and structural resources and the activity of a cardiac arrhythmia unit in a Spanish tertiary hospital for two consecutive periods: from January 12, 2020, to March 8, 2020 (“pre-COVID stage”), and from March 9, 2020, to May 2, 2020 (“COVID stage”). Data were contextualized within the number of confirmed COVID-19 cases in the region of Madrid. The measures implemented were promotion of non–face-to-face consultations, selection of urgent procedures, design of a “COVID-free” circuit for outpatient interventions, and protocolization for patients with COVID-19. A total of 3,526 consultations and 362 procedures were performed. During the COVID stage, the number of consultations remained stable, and the electrophysiology rooms’ activity decreased by 55.2% with a relative increase in the number of urgent-hospitalized cases attended (11.8% COVID-19-positive patients). The electrophysiology rooms’ activity returned to “normal” in the last week of the COVID stage, with no contagion being detected among patients or professionals. In conclusion, the measures implemented allowed us to respond safely and efficiently to the health care needs of patients with arrhythmias during the COVID-19 crisis and may be useful for other institutions facing similar situations.

Resumen Introduccion y objetivos La ivabradina es un inhibidor de la corriente If, principal determinante de la funcion marcapasos del nodulo sinusal, aprobado como antianginoso y para tratar la insuficiencia cardiaca. Existen indicios sobre su capacidad para inhibir la conduccion a traves del nodulo auriculoventricular (NAV). Sobre esta base, el proyecto BRAKE-AF plantea el uso de ivabradina como agente cronotropico negativo en fibrilacion auricular (FA). Metodos Se realizara un ensayo clinico multicentrico de fase III, aleatorizado, abierto, en paralelo, con diseno de no inferioridad, para comparar la ivabradina frente a la digoxina en 232 pacientes con FA permanente no controlada con bloqueadores beta o antagonistas del calcio; el objetivo primario es la reduccion de la frecuencia cardiaca media diurna en un Holter de 24 h a los 3 meses. El ensayo se apoyara en un estudio electrofisiologico que analizara el efecto de la ivabradina en el potencial de accion del NAV humano, utilizando un modelo experimental en celulas de ovario de hamster chino transfectadas con el ADN que codifica la expresion de los distintos canales que componen dicho potencial de accion, registrando las corrientes ionicas mediante la tecnica del parche de membrana. Resultados Se obtendra informacion tanto del efecto de la ivabradina en las corrientes ionicas y el potencial de accion del NAV como de su eficacia y su seguridad en pacientes con FA permanente. Conclusiones Los resultados del proyecto BRAKE-AF podrian permitir que la ivabradina se incluyera en el limitado arsenal de farmacos disponibles actualmente para el control de frecuencia en la FA. Ensayo registrado en ClinicalTrials.gov (Identificador: NCT03718273).

Introduction and objectives Ivabradine is an inhibitor of the If channel, the main determinant of the pacemaker function of the sinus node. The drug has been approved for the treatment of angina and heart failure. There is some evidence of its role as an inhibitor of atrial-ventricular node (AVN) conduction. The aim of the BRAKE-AF project is to assess ivabradine use for rate control in atrial fibrillation (AF). Methods A multicenter, randomized, parallel, open-label, noninferiority phase III clinical trial will be conducted to compare ivabradine vs digoxin in 232 patients with uncontrolled permanent AF despite beta-blockers or calcium channel blockers. The primary efficacy endpoint is the reduction in daytime heart rate measured by 24-hour Holter monitoring at 3 months. This clinical trial will be supported by an electrophysiological study of the effect of ivabradine on the action potential of the human AVN. To do this, an experimental model will be used with Chinese hamster ovarium cells transfected with the DNA encoding the expression of the t channels involved in this action potential and recording of the ionic currents with patch clamp techniques. Results New data will be obtained on the effect of ivabradine on the human AVN and its safety and efficacy in patients with permanent AF. Conclusions The results of the BRAKE-AF project might allow inclusion of ivabradine within the limited arsenal of drugs currently available for rate control in AF. Clinical trial registration: http://www.clinicaltrials.gov . Identifier: NCT03718273 .

Introduction A middle-age woman underwent an electrophysiologic study due to recurrent atypical atrial flutter. Methods and result Radiofrequency ablation of cavotricuspid isthmus and anterior mitral line was performed. During energy delivery on the anterior left atrial wall, interatrial dissociation and complete block of the sinus impulse to the atrioventricular (AV) node was observed. AV node activation became dependent on a subsidiary left atrial rhythm. Conclusion Anatomical location of intra and inter-atrial connections must be taken into account when performing extensive ablation procedures, specially in cases with prior cardiac surgeries.

Funding Acknowledgements Type of funding sources: None. Background Patients with left atrial appendage (LAA) thrombus are excluded for LAA occlusion (LAAO) in clinical trials. However, some of them may require this therapy due to repeated thromboembolisms despite accurate anticoagulation. Aim The aim of the study is to describe the prevalence of LAA thrombosis in patients submitted for LAAO in a high-volume center of LAAO procedures, explaining the employed technique and results in this scenario. Methods Single-center retrospective analysis including all consecutive patients referred for LAAO. Results LAA thrombus was detected by TEE in 8/76 patients referred for LAAO (10.5%). Five of them underwent LAAO despite the presence of thrombus due to clinical conditions. All the procedures were successfully performed with Amulet devices (Table). The following preventive measures were putting in place during the implants: avoidance of contrast injection into the LAA during the procedure (non-touch technique), TEE measure for device size election; and TEE device deployment guidance with special care to the the sheath orientation and depth enabling a slow and single implant of the device partially released in the LAA before complete implantation at the entrance of the LAA (Figure. A&B: Large LAA thrombus partially occupying the landing zone. C: Thrombus sealed by LAAO device. D&E: Non-touch technique: echo-guided progressive deployment of the LAAO device without thrombus shifting). No cerebral protection devices were used. TEE performed one month after the procedure ruled out the presence of residual thrombi or leaks in all cases. There were no events after a median follow-up of 17.1 months (range: 32.3-1.1) Conclusion LAAO in patient with LAA thrombus can be effectively and safely performed, in high-volume centers and with an accurate technique, under accurate TEE guidance. Abstract Figure. LAA thrombus and occlusion technique

We present the case of a 45-year-old male patient with dilated cardiomyopathy who suffers from multiple implantable cardioverter defibrillator (ICD) shocks. The analysis of the ICD tracing and the electrophysiological study allows to conclude that bundle branch re-entrant tachycardia is the most likely diagnosis, even in absence of conduction abnormalities in his basal electrocardiography.

Syncope in octogenarians represents an important problem in terms of comorbidity, quality of life and substantial medical costs, resulting from studies and treatments. An implantable loop ecorder (ILR) may improve diagnostic performance. The objective of the study was to evaluate the results of the ILR in a population of octogenarians. Prospective registry of patients receiving an implantable loop recorder in 40 Spanish centers. 128 octogenarians implanted with a device for clinical evaluation of syncope. Prospective registry recording the incidence of new symptoms or device activations within the first year after the implant, the incidence of new diagnosis and treatments, and an evaluation of the safety of this strategy in this population. Dedicated database for the registry. Forty-two patients (33% of the population) obtained a final etiological diagnosis of the syncope, which led to a specific treatment in 39 (31%) patients. No differences regarding the presence of conduction disturbances or structural heart disease were found in this population. A mortality of 4% was recorded during follow-up. The implantable loop recorder seems to be an effective and safe tool in the management of syncope in the octogenarian population.

We report the entrapment of Pulmonary Vein Ablation Catheter (Medtronic, Minneapolis, MN, USA) and its guidewire within the right pulmonary veins in two patients. The catheters could be retrieved without complications but they were disabled in both cases. This nondescribed incident should be recognized by PVAC users since it may be a source of potential severe complications during pulmonary vein isolation procedures.

Background Atrial rate-responsive pacing (RRP) has proved to be safe in pacemaker recipients with chronotropic incompetence. Although RRP is available in all current implantable cardioverter defibrillators (ICDs), the outcomes of this pacing mode in ICD patients are unknown. The aim is to evaluate the relationship between atrial RRP and atrial arrhythmias in ICD recipients. Methods Dual-chamber and triple-chamber ICD patients were included in this multicenter cohort study. Patients with permanent atrial fibrillation (AF) or VVI pacing mode were excluded. The number and duration of atrial tachycardia (AT)/AF episodes were assessed. Results Data from 415 patients and 80,707 AT/AF episodes (median duration: 0.4 hours) were collected after a 21.3 ± 14.1-month follow-up. Atrial RRP was programmed in 90 (21.7%) patients and was associated with a higher atrial pacing percentage in the overall study population (51.2 ± 33.8% vs 18.4 ± 25.7%, P 23 hours) were previous AF (odds ratio [OR]: 7.98; 95% confidence interval [CI]: 4.11–15.47; P < 0.001) and atrial RRP (OR: 3.58; 95% CI: 1.82–7.03; P < 0.001). RRP was related to a lower sustained AT/AF episodes-free survival both in patients with a history of AF (43% vs 70%, P = 0.035) and without a history of AF (82% vs 97%, P = 0.004) at 2 years. Conclusions Atrial RRP in ICD patients was related to a higher incidence of sustained atrial arrhythmias. This pacing mode may have an atrial proarrhythmic effect on ICD patients, especially among those with a history of AF.

Background Left ventricular assist devices (LVAD) are increasingly used in patients with advanced heart failure, many of whom have been or will be implanted with an implantable cardioverter defibrillator (ICD). Interaction between both devices is a matter of concern. Subcutaneous ICD (S-ICD) obtains its signals through subcutaneous vectors, which poses special challenges with regards to adequate performance following LVAD implantation. Case summary We describe the case of a 24-year-old man implanted with an S-ICD because of idiopathic dilated cardiomyopathy, severe biventricular dysfunction, and self-limiting sustained ventricular tachycardias. After the implantation of a HeartMate 3™ (Left Ventricular Assist System, Abbott) several months later, the S-ICD became useless because of inappropriate sensing due to electromagnetic interference and attenuation of QRS voltage. Discussion We reviewed the reported cases in PubMed about the concomitant use of S-ICD and LVAD. Seven case reports about the performance of S-ICD in patients with an LVAD were identified, with discordant results. From these articles, we analyse the potential causes for these differing results. Pump location and operating rates in LVAD, as well as changes in the subcutaneous-electrocardiogram detected by the S-ICD after LVAD implantation are related to sensing disturbances when used in the same patient.

Aims Phrenic paralysis is a known complication of central venous catheterization, but it is not listed as a complication related to cardiac implantable electronic device (CIED) implants. The aim of this study is to describe the incidence, causes, clinical picture, and management of phrenic paralysis occurring in this scenario. Methods and results We retrospectively analysed data from our CIED implantation database and identified those patients who suffered phrenic paralysis during the implantation procedure. Four of 891 patients (subclavian puncture in 626) developed phrenic paralysis during pacemaker or defibrillator implant procedures. Severe respiratory failure needing ventilatory support occurred in two, being the phrenic paralysis transient in all of the cases. Conclusions Transient phrenic paralysis may occur during CIED implantation probably related to the infiltration of local anaesthesia in the subclavian area. Mechanism, prevention, and management are discussed.

Aims Changes in the anatomical relationship between left phrenic nerve and coronary veins may occur due to the reverse remodelling observed in super-responders to cardiac resynchronization therapy (CRT) and might be the underlying mechanism in patients developing late-onset phrenic nerve stimulation (PNS) without evidence of lead dislodgement (LD). In this study, we sought to evaluate the role of super-response (SR) to CRT as a potential predictor of late-onset PNS. Methods and results Consecutive patients implanted with a left ventricular (LV) lead in a single centre were retrospectively analysed. Phrenic nerve stimulation was classified as 'early' when it occurred within 3 months of implantation and 'late' for occurrences thereafter. 'Late' PNS was considered related to LD (LD-PNS) when LV threshold differed by > 1 V or impedance >250 Ω from baseline values or in case of radiological displacement. Cases not meeting the former criteria were classified as 'non-LD-PNS'. Super-response was defined as a decrease ≥30% of the left ventricluar end-systolic volume at 1-year echocardiography. At 32 ± 7 months follow-up, PNS occurred in 20 of 139 patients. Late non-LD-PNS incidence was significantly higher in the SR group (8/61; 13.1%) when compared with the non-SR (1/78; 1.3%) (P = 0.010). Super-response remained the only predictor of non-LD-PNS at multivariate analysis (odds ratio: 11.62, 95% confidence interval 1.41-95.68, P = 0.023). Conclusion Incidence of late non-LD-PNS is higher among SR to CRT, suggesting a potential role of the changes in the anatomical relationship between left phrenic nerve and coronary veins.

Resumen Introduccion y objetivos Se ha demostrado que los desfibriladores automaticos implantables reducen la mortalidad de ciertos pacientes con cardiopatia. El recambio de su bateria es una situacion frecuente en la practica clinica, hasta un 30% de los implantes. El beneficio/riesgo del desfibrilador no es constante en el tiempo, y debe revaluarse en el momento del recambio. El objetivo del estudio es conocer las caracteristicas clinicas y la incidencia de terapias del desfibrilador en los pacientes sometidos a un recambio de generador. Metodos Se realizo un estudio retrospectivo multicentrico basado en los pacientes del registro nacional UMBRELLA, sometidos a recambio por agotamiento de la bateria del desfibrilador. Se analizo la incidencia de arritmias ventriculares mediante monitorizacion a distancia. Se analizaron los factores de riesgo de arritmia ventricular sostenida tras el recambio. Resultados Se incluyo a 354 pacientes (media de edad, 61,8 ± 14,5 anos; varones, 80%; prevencion secundaria, 42%; arritmias ventriculares en el generador explantado, 62%). Tras un seguimiento de 25 meses, 70 pacientes (20%) presentaron terapias apropiadas y 8 (2,3%) tuvieron descargas inapropiadas. El sexo masculino, la presencia de cardiopatia estructural, la insuficiencia cardiaca y la ausencia de resincronizacion fueron predictores independientes de la aparicion de arritmias ventriculares. Conclusiones Una quinta parte de los pacientes tiene terapias apropiadas de desfibrilador en los primeros 2 anos desde el recambio de generador. El conocimiento de los factores asociados a la aparicion de arritmias tras el recambio puede ser util para optimizar el rendimiento de la terapia.

Introduction and objectives Implantable cardioverter-defibrillators reduce mortality in some patients with heart disease. Battery replacement is a frequent occurrence in clinical practice and is required in up to 30% of implants. The benefit/risk ratio of defibrillators varies over time and should be reevaluated at the time of replacement. The aim of this study was to determine the clinical characteristics and incidence of defibrillator therapies in patients who underwent generator replacement. Methods This multicenter retrospective study involved patients from the UMBRELLA national registry who underwent replacement due to defibrillator battery depletion. The incidence of ventricular arrhythmias was determined via remote monitoring. Risk factors for sustained ventricular arrhythmia after replacement were analyzed. Results A total of 354 patients were included (mean age [standard deviation], 61.8 [14.5] years; men, 80%; secondary prevention, 42%; ventricular arrhythmias in the explanted generator, 62%). After a 25-month follow-up, 70 patients (20%) received appropriate therapies and 8 (2.3%) received inappropriate discharges. Male sex, structural heart disease, heart failure, and the absence of resynchronization were independent predictors of ventricular arrhythmia occurrence. Conclusions One-fifth of patients had appropriate defibrillator therapies in the first 2 years after generator replacement. Determination of the factors associated with arrhythmia occurrence after replacement may be useful to optimize implantable cardioverter-defibrillator treatment.

Background Catheter ablation (CA) is a highly effective therapy for the treatment of paroxysmal atrial fibrillation (AF) when compared with antiarrhythmic drug therapy (ADT). No randomized studies have compared the two strategies in persistent AF. The present randomized trial aimed to compare the effectiveness of CA vs. ADT in treating persistent AF. Methods and results Patients with persistent AF were randomly assigned to CA or ADT (excluding patients with long-standing persistent AF). Primary endpoint at 12-month follow-up was defined as any episode of AF or atrial flutter lasting >24 h that occurred after a 3-month blanking period. Secondary endpoints were any atrial tachyarrhythmia lasting >30 s, hospitalization, and electrical cardioversion. In total, 146 patients were included (aged 55 ± 9 years, 77% male). The ADT group received class Ic (43.8%) or class III drugs (56.3%). In an intention-to-treat analysis, 69 of 98 patients (70.4%) in the CA group and 21 of 48 patients (43.7%) in the ADT group were free of the primary endpoint ( P = 0.002), implying an absolute risk difference of 26.6% (95% CI 10.0–43.3) in favour of CA. The proportion of patients free of any recurrence (>30 s) was higher in the CA group than in the ADT group (60.2 vs. 29.2%; P < 0.001) and cardioversion was less frequent (34.7 vs. 50%, respectively; P = 0.018). Conclusion Catheter ablation is superior to medical therapy for the maintenance of sinus rhythm in patients with persistent AF at 12-month follow-up. Clinical Trial Registration Information NCT00863213 ([http://clinicaltrials.gov/ct2/show/[NCT00863213][2]][2]). []: http://clinicaltrials.gov/ct2/show/NCT00863213

Following the ablation of the right inferior pulmonary vein (RIPV) with a second-generation cryoballoon (180 s, −46°C), a piece …

Resumen Introduccion El pulmonary vein ablation catheter (PVAC) es un cateter decapolar circular que pretende simplificar el procedimiento de ablacion de venas pulmonares «punto a punto». Metodos Analisis retrospectivo de las ablaciones de fibrilacion auricular con PVAC en un centro. Se avanzo el PVAC a la auricula izquierda mediante puncion transeptal. Se identificaron los antros con una angiografia retrograda. Se analizo la conduccion venoatrial mediante estimulacion desde el seno coronario y desde la auricula derecha alta o en ritmo sinusal. Resultados Se incluyeron 18 pacientes (58 ± 15 anos) con fibrilacion auricular paroxistica (13; 72%) o persistente (5; 28%). Se ablacionaron 65 venas. Tras abatir los electrogramas antrales, se demostro bloqueo en 47 venas (72%). Hubo un hematoma femoral como unica complicacion. El 70% de los pacientes mantienen ritmo sinusal sin farmacos antiarritmicos (seguimiento 5 ± 1,9 meses). Discusion La experiencia inicial con el PVAC es positiva con respecto a su eficacia y seguridad.

La electrofisiologia cardiaca se esta desarrollando rapidamente como una subespecialidad dentro de la cardiologia que requiere formacion y entrenamiento adicionales. Por ello, es necesario promover y garantizar una capacitacion y una cualificacion de sus profesionales suficientes y homogeneas, que deben ser reconocidas o acreditadas como elementos de informacion para administraciones sanitarias, profesionales y usuarios. Este documento, desarrollado por la Seccion de Electrofisiologia y Arritmias de la Sociedad Espanola de Cardiologia, presenta un sistema especifico de acreditacion en electrofisiologia cardiaca para profesionales y centros de formacion. Para ser acreditado, el profesional debe ser especialista en cardiologia, haber recibido formacion especifica durante al menos 1 ano en un centro acreditado para ello y superar una prueba teorica de excelencia. Por su parte, el centro acreditado para la formacion debe estar encuadrado dentro de un servicio de cardiologia con una minima capacitacion asistencial, docente e investigadora, que se detalla en este documento.

This article contains a review of the most important developments in clinical arrhythmology and interventional cardiac electrophysiology that have been reported during the past year. Special emphasis has been placed on clinical conditions that are most prevalent in the general population as well as on progress that has been achieved using the main therapeutic approaches, whether pharmacologic or interventional.

Tras demostrar la eficacia del desfibrilador automatico implantable para reducir la mortalidad en ciertos grupos de pacientes, esencialmente con los sistemas monocamerales, se discuten las ventajas y limitaciones de los sistemas bicamerales en diferentes situaciones. Asimismo, se plantean las crecientes indicaciones de los sistemas con terapia de resincronizacion anadida. Asegurar la eficacia de la desfibrilacion de un dispositivo ha sido objeto de diferentes estudios y uno de los pilares durante el implante. Sin embargo, la metodologia empleada para su determinacion ha sido variable, ha evolucionado y hasta ha llegado a cuestionarse su comprobacion. Uno de los elementos importantes que ha de tenerse en cuenta en el momento del implante es la aparicion de complicaciones, tanto de forma inmediata como a largo plazo. Se resume y analiza la abundante bibliografia al respecto, recalcandose su incidencia y su posible prevencion. Estos aspectos resultan esenciales para reducir la morbilidad relacionada con el implante.