1,720,988 research outputs found
Clinical experience with downsized lower energy output implantable cardioverter defibrillators. Ventak Mini II Clinical Investigators
No full textTechnical improvements in cardioverter defibrillators technology has resulted in decrease in can size coupled with improved electrodes technology. A decrease in maximum energy output allows further decrease in device size. The aim of this study was to evaluate the feasibility of a single lead transvenous implant employing a downsized cardioverter-defibrillator (volume 59 cm3), with a related decrease in maximum energy output (29-31 joules as stored energy and 25-27 joules as delivered energy)
Lone paroxysmal atrial fibrillation episodes: Mechanisms of onset and patterns of atrial activation
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Left superior vena cava persistence in patients undergoing pacemaker or cardioverter-defibrillator implantation: a 10-year experience
No full textObjective: The persistence of a left superior vena cava (I,SVC) has been observed in 0.3% of the general population as established by autopsy. In the adult population, it is an important anatomic finding if a left superior approach to the heart is considered. The aim of the study was to evaluate the prevalence of a LSVC in patients undergoing pacemaker (PM) and cardioverter-defibrillator (CD) implantation. Design: We observed the prevalence of LSVC during a 10-year period; each patient undergoing PM or transvenous CD implantation received a left cephalic/left subclavian venous approach to the heart. With this technique, LSVC persistence is easily diagnosed during lead placement. Results: A total of 1,139 patients consecutively underwent PM implantation during 10 years: 4 patients had persistent LSCV (0.34%). Among 115 patients undergoing CD implantation, 2 patients with LSVC (1.7%) were observed, Overall LSVC persistence was found in 6 of 1,254 patients (0.47%), Two patients, one of whom had no light superior vena cava (RSVC), received a left-sided PM, whereas two other patients received right-sided devices. Both CD patients received a left-sided active-can device: the first patient with a right-sided lead tunneled to the left pectoral pocket, as a result of poor catheter handling through the LSVC and coronary sinus, and the second patient with a screw-in lead from]LSVC. Long-term follow-up of these patients (average +/- SD, 41 +/- 26 months) revealed absence of lead dislodgment and appropriate device function regardless of lead implantation site. Conclusions: Persistence of LSVC in adults undergoing PM/CD implantation is similar to that of the general population (0.47% in our study), The left-sided implant can be achieved by stylet shaping and by use of active fixation leads in most patients, with a reliable outcome at short term in addition to appropriate device performance at follow-up. Assessment of the RSVC is advisable when planning a right-sided implantation, since a minority of patients lacks this vessel
High defibrillation threshold at cardioverter defibrillator implantation under amiodarone treatment: Favorable effects of D,L-sotalol
No full textA 57-year-old man with primary dilated cardiomyopathy and obesity received an implantable cardioverter defibrillator because of recurrent, poorly tolerated ventricular tachycardia despite continuous treatment with amiodarone. When the device was implanted, assessment of the ability to defibrillate induced ventricular fibrillation showed high energy requirements, with a lack of conventional safety margin between energies effective at defibrillation testing and maximal device output. Treatment with oral amiodarone was withdrawn and substituted with oral sotalol. A repeat defibrillation test, performed 54 days after amiodarone withdrawal and during D,L-sotalol treatment, showed a reduction in defibrillation energy requirements. In view of this experience, replacement of amiodarone treatment with an alternate class Ill agent (D,L-sotalol or other agents, if available) can be considered as a possible option in case of high defibrillation threshold at the time of the implantation in a patient receiving continuous amiodarone treatment
Una medesima «pulsione di verità». La Resistenza come evento e la sua trasfigurazione rappresentativa
No full textPartendo dalla constatazione avanzata da Gabriele Pedullà secondo la quale la scelta per la lotta partigiana e quella per la sua trasfigurazione rappresentativa sarebbero mosse dalla medesima “pulsione di verità” (cfr. G. Pedullà, "Racconti della Resistenza", Einaudi, 2005), il saggio indaga la dimensione ontologica – la verità – e quella antropologico-filosofica – la pulsione – che innervano l’assunto in questione. In altri termini, sia analizza quale struttura ontologica stia alla base della verità che sostanzia la Resistenza e gli sforzi narrativi che la eleggono come proprio oggetto, assumendo come presupposto la natura evenemenziale della lotta resistenziale. La tesi che si cerca di dimostrare è la seguente: nella Resistenza agisce la forza di un evento – così come messo in evidenza da Jean Starobinski nel saggio "Introduction à la poésie de l’évenément" (1943) e poi argomentato dal filosofo francese Alain Badiou ("L’essere e l’evento" e "L’etica. Saggio sulla coscienza del male") –, ovvero di una modificazione della struttura ontologica della situazione storica che divelle “il ritmo delle cose e del tempo” (Calvino), che suscita, a sua volta, una modificazione della struttura antropologica del soggetto resistente, colto nel suo costituirsi come soggetto (il partigiano “avviene e viene”, come rappresentato icasticamente da Andrea Zanzotto). Un processo, quest’ultimo, che interroga le stesse capacità esperienziali e narrative dell’umano, che vengono analizzate in una lettura comparata del saggio "Il narratore. Considerazioni sull’opera di Nicolaj Leskov" di Walter Benjamin e della "Prefazione" del 1964 al "Sentiero dei nidi di ragno" di Calvino
Clinical evaluation of morphology discrimination: An algorithm for rhythm discrimination in cardioverter defibrillators
No full textThe aim of this study was to test the new morphology discrimination diagnostic algorithm for ICDs that differentiates supraventricular tachycardias (SVTs) from VTs by analysis of ventricular depolarization complexes morphology. Twenty-five patients implanted with a St. Jude Ventritex single chamber ICD were studied during electrophysiological evaluation at predischarge and were followed for 7 +/- 4 months. Sensitivity and specificity for VT detection and overall diagnostic accuracy of the morphology discrimination algorithm were calculated on 326 detected events. At electrophysiological evaluation, the algorithm was tested during 67 episodes of right atrial pacing, during 119 episodes of RV pacing (at basal interventricular septum and RV apex) and during 27 episodes of sustained AF: specificity was 98%, sensitivity was 66%, and diagnostic accuracy was 80%. Ah episodes of AF were correctly diagnosed as SVT. Exclusion of detections related to pacing at the basal interventricular septum, resulted in a specificity of 98%, a sensitivity of 85%, and a diagnostic accuracy of 93%. During follow-up, evaluation of the morphology discrimination algorithm on 113 spontaneous episodes (31 VTs, 31 AF, 7 SVTs, and 44 sinus tachycardias) exhibited a specificity of 89%, a sensitivity of 100%, and a diagnostic accuracy of 92%. In conclusion, the morphology discrimination algorithm exhibits a high specificity in discriminating VTs from SVTs, although with a corresponding reduction in sensitivity. The preliminary experience on spontaneous episodes is promising. To correct for the reduction in sensitivity, it is advisable to use this algorithm in parallel with other algorithms for rhythm discrimination (sudden onset, stability) coupled with extended high rate
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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