1,721,001 research outputs found
Atrial fibrillation burden during the post-implant period after CRT using device-based diagnostics
No full textAims: Cardiac resynchronization therapy (CRT) is increasingly used in congestive heart failure (CHF) patients (with cardiac dyssynchrony). In addition to delivering therapy, CRT devices offer a variety of diagnostic tools for continuous long-term monitoring of clinically relevant information (i.e., occurrence and duration of arrhythmia episodes). Methods and Results: Eighty-four patients with drug-refractory CHF in NYHA-class II-IV received a CRT device. The response to CRT was assessed by determining NYHA class at baseline and at 3 months follow-up. Atrial fibrillation (AF) burden (defined as time of AF per day) was continuously measured by the device. A significant gradual reduction of AF burden (from 9.88 +/- 12.61 to 4.20 +/- 9.24 [hours/day]) and number of patients experiencing AF episodes (from 26 to 13) were observed during CRT. Conclusions: (1) Diagnostic features for long-term monitoring of physiological variables provide useful information on the state and course of AF and may improve disease management. (2) AF burden reduces over time during the first 3 months after CRT implantation
Importance of AV and VV optimization during biventricular pacing systems
No full textBei Patienten mit fortgeschrittener und therapierefraktärer chronischer Herzinsuffizienz eröffnete sich mit der Einführung der biventrikulären Stimulation die kardiale Resynchronisationstherapie als ein neuer viel versprechender therapeutischer Ansatz und wurde in die Behandlungsrichtlinien aufgenommen. Die modernen Therapiedevices bieten mittlerweile die Möglichkeit eine individuelle biventrikuläre Stimulation mit unterschiedlicher zeitlicher Aktivierung des Linken und rechten Ventrikel (VV-Intervall) und der Zeitintervalle zwischen Vorhöfen und Ventrikel (AV Intervall) im Rahmen der sogenannten sequentiellen biventrikulären Stimulation durchzuführen. Die akuten hämodynamischen Auswirkungen der sequentiellen CRT, aber auch eventuelle Änderungen im zeitlichen Verlauf wurden im Rahmen dieser Arbeit untersucht.
Die invasive Messung der linksventrikulären maximalen Anstiegsgeschwindigkeit ergab sowohl nach einem Monat (+ 12,1%) als auch nach vier Monaten (+ 3,33 %) eine Zunahme unter simultaner biventrikulärer Stimulation als Ausdruck der gesteigerten Inotropie. Erfolgte dann eine Optimierung der AV und VV Zeiten zeigte sich in der 1 Monatskontrolle eine weitere Zunahme von dp/dt um 6,11 % gegenüber der simultanen biventrikulären Stimulation. Dieser Effekt der Optimierung ließ sich auch nach 4 Monaten nachweisen, hier ergab sich eine Zunahme der Anstiegsgeschwindigkeit um 6,99 % durch eine Optimierung gegenüber der simultanen Stimulation.
Im zeitlichen Verlauf konnte durch eine erneute Optimierung des biventrikulären Systems eine Zunahme der linksventrikulären Anstiegsgeschwindigkeit von 4,1% gegenüber der ursprünglich optimierten Programmierung erzielt werden.in patients with advanced and refractory chronic heart failure initiated with the introduction of biventricular pacing in cardiac resynchronization therapy as a promising new therapeutic approach and was inducted into the treatment guidelines. The modern therapeutic devices now offer the ability to carry out an individual biventricular pacing with different temporal activation of the left and right ventricles (VV interval) and the time intervals between the atria and ventricles (AV interval) within the so-called sequential biventricular pacing. The acute hemodynamic effects of sequential CRT, as well as any changes over time were examined in the context of this work.
The noninvasive measurement of left ventricular maximum rate of rise was found), both after one months (+ 12.1% and after four months (+ 3.33%) an increase in simultaneous biventricular pacing as an expression of increased inotropy. Then carried out an optimization of AV and VV time showed in the 1 months control, a further increase of dp / dt, at 6.11% compared to simultaneous biventricular pacing. This effect of optimization could be detected even after 4 months, this resulted in an increase in the rate of rise to 6.99% by optimizing to the simultaneous stimulation.
Over time could be achieved by re-optimization of biventricular system, an increase of left ventricular rate of rise of 4.1% over the originally optimized programming
Acute coronary syndrom without significant : stenosischaracterization and prognosis
No full textIn den westlichen Industrieländern stellen kardiovaskuläre Erkrankungen und hierbei insbesondere der akute Myokardinfarkt eine häufige Ursache für Morbidität und Mortalität dar. Eine rasche Diagnose ist für die Prognose akuter Koronarsyndrome entscheidend, wobei eine Differentialdiagnose von Nicht-ST-Hebungsinfarkten und anderen Troponin-positiven Koronarsyndromen oftmals sehr schwierig ist.
Die vorliegende Arbeit charakterisiert in einer retrospektiven Analyse Patienten mit Troponin-positivem akuten Koronarsyndrom mit Ausschluss von signifikanten Koronarstenosen hinsichtlich klinischer, elektrokardiographischer und laborchemischer Parameter mit dem Versuch einer Prognoseeinschätzung. Dabei erfolgte ein Vergleich zu Patienten mit erfolgter perkutaner Koronarintervention im Rahmen eines Nicht-ST-Hebungsinfarktes. Es wurden insgesamt 1437 Patienten analysiert, welche im Zeitraum von Mai 2002 bis September 2005 in die Klinik für Kardiologie des Herzzentrums Bad Berka mit akutem Thoraxschmerz und einer Erhöhung von Troponin I eingewiesen wurden. Von diesem Patientenkollektiv erfüllten 636 Patienten zunächst die Kriterien eines Nicht-ST-Hebungsinfarktes. Innerhalb von 12 Stunden wurde bei allen Patienten eine Koronarangiographie durchgeführt, welche eine Einteilung des Kollektivs in zwei Gruppen ermöglichte:
• Patienten mit akutem Coronarsyndrom ohne signifikante Stenosen ("ACSOS"; n=127)
• Patienten mit einer oder mehreren hämodynamisch relevanten Stenose(n), die einer perkutanen Coronarintervention mit Stentimplantation unterzogen wurden ("NSTEMI mit PCI"; n=509)
Bei der Analyse der "ACSOS"- mit der "NSTEMI"-Gruppe gab es keine Unterschiede hinsichtlich des Alters (66,4 vs. 65,9 Jahre; p=0,69), des Nikotinkonsums (25,3 vs. 22,7%; p=0,75) und der linksventrikulären Ejektionsfraktion (56,6 vs. 57,7%; p=0,93). Auch beim Vergleich der Troponinwerte (11,8 vs. 9,7 ng/ml; p=0,95), der CKmax (6,1 vs. 7,1µmol/l; p=0,78) sowie von CKMB (2,7 vs. 2,5%; p=0,76) waren keine signifikanten Unterschiede auffällig. ST-Strecken-Senkungen (21,3 vs.15,5%; p=0,14) und Q-Zacken (11,0 vs. 5,3%; p=0,26) im Ruhe-EKG wurden tendenziell mehr in der "ACSOS"-Gruppe festgestellt. Der vergleichsweise größere Anteil von T-Negativierungen in der "ACSOS"-Gruppe war hochsignifikant (53,5 vs. 40,6%; p=0,009). Auffällig waren die hochsignifikanten Unterschiede zugunsten der "ACSOS"-Guppe bezüglich des Nachweises von Vorhofflimmern (24,4 vs. 10,8%; p<0,001) und der Schwere der initial beklagten pectanginösen Beschwerden (76,4 vs. 40,2%; p<0,001). Auch die CRP-Werte wurden in der "ACSOS"-Gruppe signifikant höher im Vergleich zur "NSTEMI"-Gruppe gemessen (21,9 vs. 16,3mg/l; p=0,004). Bei der Betrachtung der kardiovaskulären Risikofaktoren gab es im NSTEMI-Kollektiv hochsignifikant mehr Patienten mit Diabetes mellitus (39,1 vs. 20,5%; p<0,001), arterieller Hypertonie (89,1 vs. 69,3%; p<0,001) und Hyperlipidämie (61,1 vs. 43,3%; p<0,001). Auch regionale Wandbewegungstörungen wurden hochsignifikant mehr bei den Patienten mit NSTEMI nachgewiesen (75,2 vs. 47,2%; p<0,001).
Die Tako-Tsubo-Kardiomyopathie und die virusinduzierte Myokarditis waren die häufigsten Krankheitsbilder in der "ACSOS"-Gruppe.
Im Follow-up gab es in der "NSTEMI"-Gruppe signifiikant mehr Myokardreinfarkte (8,5 vs. 3,4%; p=0,005) und Rehospitalisierungen aus kardialer Ursache (70,3 vs. 6,1%; p<0,001). Keine Unterschiede gab es bei der Mortalität (4,2 vs. 4,9%; p=1,0).
Zusammenfassend ist anhand der eigenen Ergebnisse in Übereinstimmung mit den Daten aus der Literatur festzustellen, dass die Genese des akuten Thoraxschmerzes mit Troponinerhöhung bei Patienten ohne angiographischen Nachweis einer signifikanten Koronarstenose in den meisten Fällen unklar bleibt. Es konnte nachgewiesen werden, dass man anhand der Schwere des Angina-pectoris-Anfalles und der Höhe des Troponinwertes nicht automatisch auf das Vorliegen eines Myokardinfarktes schließen kann. Der Nachweis der klassischen kardiovaskulären Risikofaktoren Diabetes mellitus, arterielle Hypertonie und Hyperlipidämie machen einen Myokardinfarkt wahrscheinlicher, schließen aber eine andere Genese nicht aus.
Patienten mit durchgemachtem NSTEMI haben ein vergleichsweise höheres Risiko für das Auftreten eines Myokard-Reinfarktes und für Rehospitalisierungen aus kardialer Ursache. Der erhöhte Nachweis des C-reaktiven Proteins in der "ACSOS"-Gruppe lässt inflammatorische Prozesse vermuten. Besonders hervorzuheben ist in den eigenen Ergebnissen der deutlich erhöhte Anteil von Patienten mit Vorhofflimmern in der "ACSOS"-Gruppe.
In einer zusammenfassenden Bewertung konnte diese Arbeit nachweisen, dass die im Klinikalltag verfügbaren nichtinvasiven Diagnostika keine sichere Unterscheidung zwischen einem NSTEMI und einem ACS ohne Nachweis von signifikanten Koronarstenosen ermöglichen. Es ist somit abschließend zu betonen, dass die Durchführung einer Koronarangiographie im Rahmen der Akutdiagnostik des akuten Koronarsyndroms weiterhin unverzichtbar ist.In the Western industrialized nations, cardiovascular disease, and in particular acute myocardial infarction, is a major cause of morbidity and mortality. Early diagnosis is critical for the prognosis of acute coronary syndromes, but it is often very difficult to make a differential diagnosis of non-ST elevation infarction and other coronary syndromes with elevated troponin levels.
This paper makes a retrospective analysis of patients suffering from acute coronary syndrome with elevated troponin levels, excluding significant coronary stenosis. Reference is made to clinical, electrocardiographic and laboratory parameters and an attempt at a prognosis is made. The research involved a comparison of patients who had received percutaneous coronary intervention due to a non-ST elevation infarction. A study was made of 1,437 patients who were admitted to the Cardiology Clinic in Bad Berka between May 2002 and September 2005 suffering from acute thoracic pain and elevated levels of troponin I. Of these, 636 patients fulfilled the initial criteria, in that they were suffering from a non-ST elevation infarction. A coronary angiography was carried out on each patient within 12 hours, after which the patients were divided into two groups:
• Patients with acute coronary syndrome without significant stenosis ("ACSOS"; n=127)
• Patients with one or more haemodynamically-relevant stenoses that were treated with a percutaneous coronary intervention with stent insertion ("NSTEMI with PCI"; n=509)
An analysis of the "ACSOS" and "NSTEMI" groups showed no differences due to age (66.4 vs. 65.9 years old; p=0.69), nicotine consumption (25.3 vs. 22.7%; p=0.75) and left ventricular ejection fraction (56.6 vs. 57.7%; p=0.93). There were also no significant differences when comparing levels of troponin (11.8 vs. 9.7 ng/ml; p=0,95), maximum CK (6.1 vs. 7.1µmol/l; p=0.78) and CKMB (2.7 vs. 2.5%; p=0.76). ST segment depression (21.3 vs. 15.5%; p=0.14) and Q-waves (11.0 vs. 5.3%; p=0.26) during resting ECG were more prevalent in the "ACSOS" group. The comparatively higher amount of negative T-waves in the "ACSOS" group was highly significant (53.5 vs. 40.6%; p=0.009). Highly significant differences were noted in favour of the "ACSOS" group with regard to atrial fibrillation (24.4 vs. 10.8%; p<0.001) and the severity of the initial anginal pain (76.4 vs. 40.2%; p<0.001). CRP levels were also significantly higher in the "ACSOS" group than in the "NTEMI" group (21.9 vs. 16.3mg/l; p=0.004). With respect to cardiovascular risk factors, the NSTEMI group contained highly significantly more patients suffering from diabetes mellitus (39.1 vs. 20.5%; p<0.001), arterial hypertension (89.1 vs. 69.3%; p<0.001) and hyperlipidemia (61.1 vs. 43.3%; p<0.001). Regional wall motion abnormalities were also found to be highly significantly more than in patients with NSTEMI (75.2 vs. 47.2%; p<0.001).
Takotsubo cardiomyopathy and virus-induced myocarditis were the most common diseases in the "ACSOS" group.
Follow-up examinations showed that the "NSTEMI" group had significantly more myocardial reinfarctions (8.5 vs. 3.4%; p=0.005) and rehospitalisations due to cardiac conditions (70.3 vs. 6.1%; p<0.001). There was no difference in mortality (4.2 vs. 4.9%; p=1.0).
In summary, own research and data from previous studies show that the cause of thoracic pain with elevated troponin levels in patients without angiographic evidence of significant coronary stenosis remains unclear in most cases. It was demonstrated that it should not be automatically assumed that a myocardial infarction has taken place based on the severity of the angina attack and on the patient's troponin levels. Classic cardiovascular risk factors such as diabetes mellitus, arterial hypertension and hyperlipidemia increase the likelihood of myocardial infarction, but do not exclude the possibility of another cause.
Patients who have undergone NSTEMI have a relatively higher risk of myocardial reinfarction and of rehospitalisation due to cardiac conditions. The increased levels of C-reactive proteins in the "ACSOS" group suggest the presence of inflammatory processes. The considerably higher numbers of patients with atrial fibrillation in the "ACSOS" group should be particularly noted.
In a final assessment, this paper showed how the non-invasive diagnostic procedures that are normally used in clinics are not able to clearly distinguish between an NSTEMI and an ACS without evidence of significant coronary stenosis. In conclusion, it should be stressed that it remains essential to continue carrying out coronary angiographies as part of the acute diagnosis of acute coronary syndrome
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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