Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Pacing and clinical electrophysiology 23 (2000), S. 0 
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The analysis oft wave alternans (TWA) was introduced to identify patients with an increased risk of ventricular tachyarrhythmias. The inducibility of ventricular tach-yarrhythmias and the spontaneous arrhythmic events are correlated with a positive TWA in patients with a reduced left ventricular ejection fraction and survived myocardial infarction. In contrast, this study is the first to investigate the correlation of a survived sudden cardiac death and TWA in patients without coronary heart disease and only slightly decreased left ventricular function. Sixty patients were included in the study. The TWA analysis was performed using the Cambridge Heart system (CH2000). Patients were sitting on a bicycle ergometer and exercised with a gradual increase of workload to maintain a heart rate of at least 105 beats/min. The exercise test was stopped after recording 254 consecutive low noise level heart beats. The electrocardiographic signals were digitally processed using a spectral analysis method. The magnitude of TWA was measured at a frequency of 0.5 cycles/beat. A TWA was defined as positive if the ratio between TWA and noise level was 〉 3.0 and the amplitude of the TWA was 〉 1.8 μV. Twelve (20%) of the included 60 patients showed a positive TWA. The sensitivity concerning a previous arrhythmic event amounted to 65%, the specificity up to 98%, respectively. The alternans ratio was significantly higher in patients with a previous event (30.3 ± 53.2 vs 2.9 ± 5.9, P 〈 0.001) and cumulative alternans voltage (4.67 ± 3.55 vs 1.75 ± 1.88 μV, P 〈 0.001). In 19 patients, invasively investigated by an electro-physiological study, a significant correlation between inducibility of tachyarrhythmias and a positive TWA result was found (Spearman R = 0.51, P = 0.01). In conclusion, the TWA analysis seems to identify patients with nonischemic Cardiomyopathy who are at an increased risk of ventricular tachyarrhythmias.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: For evaluation of patients with an increased risk of sudden cardiac death, the analyses of ventricular late potentials, heart rate variability, and baroreflexsensitivity are helpful. But so far, the prediction of a malignant arrhythmic event is not possible with sufficient accuracy, For a better risk stratification other methods are necessary. In this study the importance of the ChRS for the identification of patients at risk for ventricular tachyarrhythmic events should be investigated. Of 41 patients included in the study, 26 were survivors of sudden cardiac arrest. Fifteen patients were not resuscitated, of whom 6 patients had documented monomorphic ventricular tachycardia and 9 had no ventricular tachyarrhythmias in their prior history. All patients had a history of an old myocardial infarction (〉 1 year ago). For determination of the ChRS the ratio between the difference of the RR intervals in the ECG and the venous pO2 before and after a 5-minute oxygen inhalation via a nose mask was measured (ms/mmHg). The 26 patients with survived sudden cardiac death showed a significantly decreased ChRS compared to those patients without a tachyarrhythmic event (1.74 ± 1.02 vs 6.97 ± 7.14 ms/mmHg, P 〈 0.0001). The sensitivity concerning a survived sudden cardiac death amounted to 88% for a ChRS below 3.0 ms/mmHg. During a 12-month follow-up period, the ChRS was significantly different between patients with and without an arrhythmic event (1.64 ± 1.06 vs 4.82 ± 5.83 ms/mmHg, P 〈 0.01). As a further method for evaluation of patients with increased risk of sudden cardiac death after myocardial infarction the analysis of ChRS seems to be suitable and predicts arrhythmias possibly more sensitive than other tests of neurovegetative imbalance. The predictive importance has to be examined by prospective investigations in larger patient populations.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Herzschrittmachertherapie & Elektrophysiologie 11 (2000), S. 11-30 
    ISSN: 1435-1544
    Keywords: Key words Epicardium – coronary veins – coronary arteries –¶multielectrode/multipolar mapping – basket catheter – microcatheter –¶ablation – ethanol – ventricular tachyarrhythmia ; Schlüsselwörter Epikard – Koronarvenen – Koronararterien –¶Multipolares Mapping – Mikrokatheter – Ablation – Alkohol –¶Basketkatheter – ventrikuläre Tachykardien
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Epikardiale Strukturen sind bislang wenig betretenes Gebiet, wenn es um Mapping oder Ablation tachykarder Herzrhythmusstörungen geht. Bei einem kleineren Teil von Patienten mit offensichtlich epikardialem Verlauf arrhythmogener Strukturen kann es jedoch notwendig werden, Koronarvenen oder -arterien aufzusuchen, um den Arrhythmiefokus zu lokalisieren und ggf. auch dort zu beseitigen. Bisher liegen nur Einzelerfahrungen zum Koronarvenen-Mapping bei ventrikulären Tachykardien vor. Insbesondere die nicht ischämischen Herzerkrankungen, z.B. die Chagas-Erkrankung, die dilatative Kardiomyopathie und idiopathische ventrikuläre Tachykardien, weisen nicht selten einen epikardialen Ursprung bzw. Durchbruch auf. Ein multipolares Mapping mit 2–3 French Mikrokathetern mit bis zu 16 Polen ermöglicht es, nahezu alle Koronarvenenabschnitte zu erreichen und den Arrhythmiefokus zu lokalisieren. In Ausnahmefällen kann auch ein Mikrokatheter-Mapping in Koronararterien durchgeführt werden, um die Lokalisation postinfarzieller ventrikulärer Tachykardien zu orten. Möglich ist auch ein direkter Zugang in den Epiperikardraum mittels transkutaner Perikardpunktion, um ein nicht durch anatomische Gefäßstrukturen limitiertes Mapping des gesamten Epikards durchführen zu können. Während das Koronarvenen-Mapping sicher, zuverlässig und aussagekräftig bei epikardial lokalisierten Arrhythmieherden durchgeführt werden kann, bedarf es für die verschiedenen ablativen Verfahren in epikardialen Strukturen noch weiterer Evaluierung hinsichtlich Sicherheit und Effizienz.¶   Das multipolare Basket-Mapping bedient sich eines flexiblen Körbchens bestehend aus bis zu 8 Armen, die mit multiplen Elektroden besetzt sind. Über einen Führungskatheter in den linken oder rechten Ventrikel eingeführt entfaltet sich das Körbchen und legt sich dem Endokard an. Nach Induktion der ventrikulären Tachykardien kann innerhalb weniger Sekunden die Lokalisation des Quellgebietes durchgeführt werden. Daher ist mit diesem Verfahren auch ein Mapping kurz dauernder ventrikulärer Tachykardien möglich. Erste Ergebnisse zeigen, dass das Basket-Mapping effektiv und relativ sicher ist. Derzeit sind computergestützte Animationsverfahren in Erprobung, um die Fülle der registrierten Signale in ein dreidimensionales Koordinatensystem zu transferieren, welches die topographische Steuerung des Ablationskatheters erleichtert.¶   Vor einer klinischen Etablierung sind weitere Entwicklungen und methodenvergleichende Untersuchungen erforderlich.
    Notes: Summary Epicardial structures are only rarely used for mapping and ablation of supraventricular and ventricular arrhythmias with the exception of WPW syndromes. However in a small percentage of patients obviously presenting an epicardial course of their arrhythmogenic structures, it may become necessary to seek out coronary veins and arteries in order to localize and eventually directly ablate the foci. Only single experiences are available in coronary vein mapping for ventricular tachycardias. In particular non-ischemic conditions like Chagas‘ disease, dilative cardiomyopathy and idiopathic left ventricular tachycardias tend to demonstrate an epicardial origin respectively breakthrough. By multipolar mapping using 2–3 French microcatheters with up to 16 poles, almost all coronary vein regions and arrhythmogenic foci can be reached respectively identified. In exceptional cases, microcatheter mapping may also be carried out in coronary arteries for localizing ventricular tachycardias for example due to remote myocardial infarction. Recently a direct approach to the epicardial space by transthoracic pericardial puncture has been introduced to perform a complete mapping of the epicardial surface not being limited by vascular structures. While coronary vein mapping can be considered a safe, reliable and helpful aid in identifying and localizing epicardial arrhythmogenic foci, the different ablative procedures still need to be evaluated and standardized with respect to safety and efficacy.¶   Multipolar basket mapping means an endocardial mapping procedure using a flexible basket consisting of up to 8 arms provided with multiple electrodes. After introducing the basket through a guiding catheter into the ventricle, the basket is distended and attached to the endocardium. An induced ventricular tachycardia may be mapped in seconds making this technique advantageous for nonsustained ventricular tachycardias. Initial results indicate basket mapping to be efficacious and relatively safe. At present, computer-based animation techniques are being evaluated for the transfer of the large amount of endocardial signal data registered into a three-dimensional coordinate system in order to guide the ablation catheter. Before basket mapping may be considered a clinically established tool, further developments and studies comparing basket with other mapping techniques are needed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...