Emerging role of cardiac computed tomography in heart failure.

Despite medical advancements, the prognosis of patients with heart failure remains poor. While echocardiography and cardiac magnetic resonance imaging remain at the forefront of diagnosing and monitoring patients with heart failure, cardiac computed tomography (CT) has largely been considered to have a limited role. With the advancements in scanner design, technology, and computer processing power, cardiac CT is now emerging as a valuable adjunct to clinicians managing patients with heart failure. In the current manuscript, we review the current applications of cardiac CT to patients with heart failure and also the emerging areas of research where its clinical utility is likely to extend into the realm of treatment, procedural planning, and advanced heart failure therapy implementation.

Electrophysiology devices and the regulatory approval process within the U.S. FDA and abroad.

Almost all electrophysiology (EP) devices need to obtain premarket approval before they can be commercially sold and available for use in the community. The US Food and Drug Administration (FDA) has different paths to market approval depending on the intended use and the associated risks of the device. The European Union and Japan have device approval processes that have many similarities as well as differences to the US regulatory system. This paper describes some of the history and background of the US device approval process with an emphasis on EP devices. It provides an overview of the different regulatory pathways in the USA that are currently being utilized and contrasts them to the procedures often used in the European Union and in Japan. It also touches on the impact of the twenty-first Century Cures Act and how the balance between premarket and postmarket regulatory oversight is continually being examined and refined.

Multiple Shifts of the Earliest Retrograde Atrial Activation Site Along the Tricuspid Annulus During the Fast-Slow Form of Atrioventricular Nodal Reentrant Tachycardia by Radiofrequency Modification.

A 70-year-old woman was admitted for treatment of supraventricular tachycardia. Ventriculoatrial conduction was revealed through programmed ventricular stimulation; the coronary sinus ostium (CSos) was the earliest atrial activation site. The fast-slow forms of atrioventricular nodal reentrant tachycardia (AVNRT) were induced by ventricular extra-stimuli. During tachycardia, the earliest atrial activation site was located at the bottom of CSos. Radiofrequency (RF) energy application to this site resulted in the delay of local electrical potential, prolongation of tachycardia cycle length, and a shift of the earliest retrograde activation site to the roof of CSos. Subsequent ablation induced a similar shift to the inferior tricuspid annulus and to the right posterior septum. Finally, RF energy application to the right posterior septum resulted in the termination of tachycardia, which was not induced afterward. Multiple shifts in the earliest retrograde atrial activation site along the tricuspid annulus after each slow pathway ablation suggested that annular tissue plays a substantial role as a substrate for AVNRT.

High-speed mechano-active multielectrode array for investigating rapid stretch effects on cardiac tissue.

Systematic investigations of the effects of mechano-electric coupling (MEC) on cellular cardiac electrophysiology lack experimental systems suitable to subject tissues to in-vivo like strain patterns while simultaneously reporting changes in electrical activation. Here, we describe a self-contained motor-less device (mechano-active multielectrode-array, MaMEA) that permits the assessment of impulse conduction along bioengineered strands of cardiac tissue in response to dynamic strain cycles. The device is based on polydimethylsiloxane (PDMS) cell culture substrates patterned with dielectric actuators (DEAs) and compliant gold ion-implanted extracellular electrodes. The DEAs induce uniaxial stretch and compression in defined regions of the PDMS substrate at selectable amplitudes and with rates up to 18 s-1. Conduction along cardiomyocyte strands was found to depend linearly on static strain according to cable theory while, unexpectedly, being completely independent on strain rates. Parallel operation of multiple MaMEAs provides for systematic high-throughput investigations of MEC during spatially patterned mechanical perturbations mimicking in-vivo conditions.

Organic Electrochemical Transistor Arrays for In Vitro Electrophysiology Monitoring of 2D and 3D Cardiac Tissues.

Here, a multichannel organic electrochemical transistor (OECT) array is reported for electrophysiological monitoring and mapping of action potential propagation of a wide range of cardiac cells, including cell lines, primary cell lines, and human-sourced stem cell derivatives in 2D and 3D structures. The results suggest that the ability to exploit this OECT-based platform to map 2D action potential propagation provides a viable strategy to better characterize cardiac cells in response to various chronotropic drugs. The effects of chronotropic agents Isoproterenol and Verapamil on cardiac tissues validate the utility of OECT for drug screening capability, and a preliminary demonstration of a 64-channel OECT array to monitor the cardiac action potentials for better spatial resolution is presented. The study demonstrates that OECT will be a viable and versatile platform for applications in medical and pharmacological industries.

A review of bioelectrodes for clinical electrophysiologists.

The theory of bioelectrodes describes the rules governing the passage of electrical charge between electrodes and electrolytes. In this review, we explain the basis of bioelectrodes with focus on clinical electrophysiology. The central concept is the double-layer capacitance that forms in the interface between the electrode and tissue. This phenomenon controls charge transfer between electrodes and tissues and contributes to detrimental effects such as electrode polarization and motion artifacts. Many methods critical to the practice of electrophysiology, including fractally coated pacemaker leads, biphasic stimuli, signal filtering, and the use of nonpolarizable electrodes, are devised to mitigate these problems. Our goal is to provide a robust and intuitive background on these topics for practicing electrophysiologists to help them better understand how catheters and leads work and to assist them with optimizing and troubleshooting electrophysiology systems.

Simultaneous electrical recording of cardiac electrophysiology and contraction on chip.

Prevailing commercialized cardiac platforms for in vitro drug development utilize planar microelectrode arrays to map action potentials, or impedance sensing to record contraction in real time, but cannot record both functions on the same chip with high spatial resolution. Here we report a novel cardiac platform that can record cardiac tissue adhesion, electrophysiology, and contractility on the same chip. The platform integrates two independent yet interpenetrating sensor arrays: a microelectrode array for field potential readouts and an interdigitated electrode array for impedance readouts. Together, these arrays provide real-time, non-invasive data acquisition of both cardiac electrophysiology and contractility under physiological conditions and under drug stimuli. Human induced pluripotent stem cell-derived cardiomyocytes were cultured as a model system, and used to validate the platform with an excitation-contraction decoupling chemical. Preliminary data using the platform to investigate the effect of the drug norepinephrine are combined with computational efforts. This platform provides a quantitative and predictive assay system that can potentially be used for comprehensive assessment of cardiac toxicity earlier in the drug discovery process.

The Current State and Future Potential of Pediatric and Congenital Electrophysiology.

Pediatric electrophysiologists specialize in the diagnosis and treatment of rhythm abnormalities in pediatric, congenital heart disease, and inherited arrhythmia syndrome patients. The field originated out of the unique knowledge base that rhythm management in young patients required. In the 1970s, pediatric electrophysiology was recognized as a distinct cardiac subspecialty and it has evolved rapidly since that time. Despite the considerable growth in personnel, technology, and complexity that the field has undergone, further opportunities to progress pediatric electrophysiology exist. In this review, we highlight some of the clinical focus of pediatric and adult congenital electrophysiologists to date and identify areas within this specialty where the pediatric and congenital electrophysiology community could come together in order to drive improvements in rhythm management for patients.

Non-fluoroscopic catheter tracking for fluoroscopy reduction in interventional electrophysiology.

A technological platform (MediGuide) has been recently introduced for non-fluoroscopic catheter tracking. In several studies, we have demonstrated that the application of this non-fluoroscopic catheter visualization system (NFCV) reduces fluoroscopy time and dose by 90-95% in a variety of electrophysiology (EP) procedures. This can be of relevance not only to the patients, but also to the nurses and physicians working in the EP lab. Furthermore, in a subset of indications such as supraventricular tachycardias, NFCV enables a fully non-fluoroscopic procedure and allows the lab staff to work without wearing lead aprons. With this protocol, we demonstrate that even complex procedures such as ablations of atrial fibrillation, that are typically associated with fluoroscopy times of >30 min in conventional settings, can safely be performed with a reduction of >90% in fluoroscopy exposure by the additional use of NFCV.

Electrophysiological characterization of spontaneously contracting cell aggregates obtained from rainbow trout larvae with multielectrode arrays.

BACKGROUND/AIMS: Safety pharmacology requires novel model systems for the detection of cardiac side effects. Ranging from cell-based systems to model organisms, no model available to date reflects the complexity of the human heart and evokes the great need for improved and more affordable systems. Many drugs interact with hERG potassium channels and consequently cause life threatening ventricular arrhythmias, further highlighting the importance of suitable model systems. METHODS: Spontaneously Contracting Cell aggregates (SCC) as a 3D in vitro heart-syncytium obtained from rainbow trout larvae represent a novel model system for cardiac safety pharmacology. SCCs can be harvested cost-effectively and kept in culture for several weeks while retaining their functionality and displaying contraction rates similar to the human heart. RESULTS: Extracellular field potential recordings with multielectrode arrays revealed significant prolongation of field potential duration upon administration of common hERG potassium channel blockers. Infusion of 1 µM Dofetilide and 10 µM Terfenadine prolonged field potentials 10 fold and 2 fold, respectively. In addition, SCCs enabled analysis of autonomous contraction frequencies. CONCLUSION: Thus, SCCs represent a novel and low-cost cardiac model system of the human heart for application in safety pharmacology.

Registro Español de Ablación con Catéter. XII Informe Oficial de la Sección de Electrofisiología y Arritmias de la Sociedad Española de Cardiología (2012) / Spanish Catheter Ablation Registry. 12th Official Report of the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias (2012)

Introducción y objetivos. Se detallan los resultados del Registro Nacional de Ablación del año 2012. Métodos. La recogida de datos se llevó a cabo mediante dos sistemas. De manera retrospectiva con la cumplimentación de un formulario y de manera prospectiva a través de una base de datos común. La elección de una u otra fue voluntaria para cada uno de los centros. Resultados. Se recogieron datos de 74 centros. El número total de procedimientos de ablación fue 11.042, con una media de 149 ± 103 procedimientos. Los tres sustratos abordados con más frecuencia fueron la taquicardia intranodular (n = 2.842; 25,7%), la ablación del istmo cavotricuspídeo (n = 2.485; 23%) y las vías accesorias (n = 1.999; 18%). El cuarto sustrato fue la ablación de fibrilación auricular (n = 1.852; 17%), que mostró un incremento del 21% con respecto a los datos de 2011. La ablación de arritmias ventriculares ha permanecido estable, pero han disminuido los procedimientos sobre las asociadas a cicatriz tras infarto. La tasa total de éxito fue del 94,9%; la de complicaciones mayores, del 1,9% y la de mortalidad, del 0,04%. Conclusiones. El registro del año 2012 mantiene una línea de continuidad ascendente en el número de ablaciones realizadas y muestran, en líneas generales, una elevada tasa de éxito y bajo número de complicaciones. Continúa el aumento del abordaje de sustratos más complejos, especialmente de la fibrilación auricular (AU)

Introduction and objectives. This article presents the findings of the 2012 Spanish Catheter Ablation Registry. Methods. Data were collected in 2 ways: retrospectively using a standardized questionnaire, and prospectively using a central database. Each participating center selected its own preferred method of data collection. Results. Seventy-four Spanish centers voluntarily contributed data to the survey. A total of 11 042 ablation procedures were analyzed, averaging 149 (103) per center. The 3 main conditions treated were atrioventricular nodal reentrant tachycardia (n=2842; 25.7%), cavotricuspid isthmus (n=2485; 23%), and accessory pathways (n=1999; 18%). Atrial fibrillation was the fourth most common substrate treated (n=1852; 17%), representing a slight increase. The number of ventricular arrhythmia ablation procedures was similar to that of 2011, but there was a decrease in procedures for ventricular tachycardia associated with postinfarction scarring. The overall success rate was 94.9%, major complications occurred in 1.9%, and the overall mortality rate was 0.04%. Conclusions. Data from the 2012 registry show that the number of ablations performed continued to increase. Overall, they also show a high success rate and a low number of complications. Ablation of complex substrates continued to increase, particularly in the case of atrial fibrillation (AU)

Registro Español de Desfibrilador Automático Implantable. IX Informe Oficial de la Sección de Electrofisiología y Arritmias de la Sociedad Española de Cardiología (2012) / Spanish Implantable Cardioverter-defibrillator Registry. Ninth Official Report of the Spanish Society of Cardiology Electrophysiology and Arrhythmias Section (2012)

Introducción y objetivos. Se presentan los resultados del Registro Español de Desfibrilador Automático Implantable de 2012 elaborado por la Sección de Electrofisiología y Arritmias de la Sociedad Española de Cardiología. Métodos. Se envió de forma prospectiva a la Sociedad Española de Cardiología la hoja de recogida de datos cumplimentada voluntariamente por cada equipo implantador. Resultados. El número de implantes comunicados fue de 4.216 (el 80,84% del total de implantes estimado). La tasa de implantes fue 91,2 por millón de habitantes y la estimada, 113. Los primoimplantes fueron el 69,4%. Se obtuvieron datos de 161 hospitales (6 menos que en 2011). La mayoría de los implantes (83,4%) se realizaron en varones. La media de edad fue 61,8 ± 13,4 años. La mayoría de los pacientes presentaban disfunción ventricular grave o moderada-grave y clase funcional II de la New York Heart Association. La cardiopatía más frecuente fue la isquémica, seguida de la dilatada. Las indicaciones por prevención primaria han disminuido este año respecto al incremento continuo de años anteriores y son el 58,1% de los primoimplantes. Los implantes realizados por electrofisiólogos han seguido aumentado, y ahora son el 81% del total. Conclusiones. El Registro Español de Desfibrilador Automático Implantable de 2012 recoge información del 80,8% de los implantes realizados en España. Es el segundo año de nuestra serie en que el número de implantes disminuye ligeramente respecto al año previo. Este año también han disminuido los realizados por indicación de prevención primaria (AU)

Introduction and objectives. To summarize the findings of the Spanish Implantable Cardioverter-defibrillator Registry for 2012 compiled by the Electrophysiology and Arrhythmias Section of the Spanish Society of Cardiology. Methods. Prospective data recorded voluntarily on single-page questionnaires were sent to the Spanish Society of Cardiology by each implantation team. Results. Overall, 4216 device implantations were reported, representing 80.8% of the estimated total number of implantations. The reported implantation rate was 91.2 per million population and the estimated total implantation rate was 113 per million. The proportion of first implantations was 69.4%. We collected data from 161 hospitals (6 fewer than in 2011). The majority of implantable cardioverter-defibrillator recipients were men (83.4%). Mean age was 61.8 (13.4) years. Most patients had severe or moderate-to-severe ventricular dysfunction and were in New York Heart Association functional class II. Ischemic heart disease was the most frequent underlying cardiac condition, followed by dilated cardiomyopathy. The number of indications for primary prevention decreased over the previous year and now account for 58.1% of first implantations. Overall, 81% of the implantable cardioverter-defibrillator were implanted by cardiac electrophysiologists. Conclusions. The 2012 Spanish Implantable Cardioverter-defibrillator Registry includes data on 80.8% of all implantable cardioverter-defibrillators implantations performed in Spain. This is the second consecutive year in which the number of implantations has slightly decreased compared to the previous year. This year, the percentage of implantations for primary prevention indications also decreased (AU)

Periaortitis fibrosa con infiltración en las válvulas aórtica y mitral / Fibrotic periaortitis infiltrating into the aortic and mitral valves

No disponible

Dronedarona: una opción en el tratamiento de las arritmias ventriculares / Dronedarone: an option in the treatment of ventricular arrhythmias

No disponible

Novedades en alteraciones del ritmo cardiaco: electrofisiología cardiaca, arritmias y estimulación cardiaca / Innovations in heart rhythm disturbances: cardiac electrophysiology, arrhythmias, and cardiac pacing

En este artículo se revisan los trabajos más relevantes en el campo de las arritmias publicados en 2012, incluyendo aritmología clínica, técnicas de ablación, estimulación cardiaca y genética de la muerte súbita (AU)

This article reviews the most relevant articles published in 2012 in the field of arrhythmias, on subjects that include clinical arrhythmology, ablation, cardiac pacing, and the genetics of sudden cardiac death (AU)

Taquicardia ventricular en la enfermedad coronaria / Ventricular tachycardia in coronary artery disease

Las arritmias ventriculares contribuyen de manera importante en la morbilidad y mortalidad de los pacientes con enfermedad coronaria. La fibrilación ventricular es la causa de la mayor parte de las muertes que se producen en la fase aguda de la isquemia, mientras que la taquicardia ventricular monomorfa sostenida, debida a una reentrada generada en el tejido cicatrizal aparece sobre todo en el contexto de un infarto de miocardio cicatrizado, principalmente en pacientes con una fracción de eyección ventricular izquierda más baja. A pesar de los importantes avances que se han producido en la educación sanitaria de la población y en el tratamiento del infarto de miocardio, el riesgo de taquicardia ventricular en la población global con enfermedad coronaria continúa siendo un problema importante en la práctica clínica. La evaluación inicial del paciente que presenta una taquicardia ventricular requiere un electrocardiograma de 12 derivaciones, que puede ser útil para confirmar el diagnóstico, sugerir la presencia de una posible cardiopatía subyacente, e identificar la localización del circuito de taquicardia ventricular. El estudio electrofisiológico invasivo suele ser crucial para determinar el mecanismo de la arritmia una vez inducida, y para guiar la ablación. El abordaje utilizado para la ablación de la taquicardia ventricular depende de varios factores, como la inducibilidad, la sostenibilidad y la tolerancia clínica a la taquicardia ventricular. Este artículo revisa también otras opciones terapéuticas para los pacientes con taquicardia ventricular asociada a la enfermedad coronaria, como el tratamiento farmacológico antiarrítmico, la ablación quirúrgica y las indicaciones actuales de desfibrilador automático implantable (AU)

Ventricular arrhythmias are important contributors to morbidity and mortality in patients with coronary artery disease. Ventricular fibrillation accounts for the majority of deaths occurring in the acute phase of ischemia, whereas sustained, monomorphic ventricular tachycardia due to reentry generated in the scar tissue develops most often in the setting of healed myocardial infarction, especially in patients with lower left ventricular ejection fraction. Despite determinant advances in population education and myocardial infarction management, the ventricular tachycardia risk in the overall population with coronary artery disease continues to be a major problem in clinical practice. The initial evaluation of a patient presenting with ventricular tachycardia requires a 12-lead electrocardiogram, which can be helpful to confirm the diagnosis, suggest the presence of potential underlying heart disease, and identify the location of the ventricular tachycardia circuit. An invasive electrophysiologic study is usually crucial to determine the mechanism of the arrhythmia once induced and to provide guidance for ablation. The approach for ventricular tachycardia ablation depends on several factors, including inducibility, sustainability, and clinical tolerance of ventricular tachycardia. The paper also reviews other therapeutic options for patients with ventricular tachycardia associated with coronary artery disease, including antiarrhythmic drug therapy, surgical ablation, and current implantable cardioverter-defibrillator indications (AU)