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  • 1
    Electronic Resource
    Electronic Resource
    Radiofrequency Catheter Ablation of Tachycardia in Patients with Congenital Heart Disease (2000)
    Springer
    Pediatric cardiology 21 (2000), S. 557-575 
    Details
    ISSN: 1432-1971
    Keywords: Key words: Congenital heart disease — Radiofrequency current ablation — Incisional tachycardia — Atrial flutter — Ventricular tachycardia — Adult congenital heart disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Patients with anomalies of the heart frequently suffer from arrhythmias that either are associated with a congenital heart defect or result from the course of the disease. For most of the bradyarrhythmias, appropriate timing of the initiation of treatment is more challenging than its eventual execution. In the case of tachycardias, technical aspects of treatment require more attention because the often imperative impact such tachycardias have on quality of life, morbidity, and mortality determine intervention timing. Increasingly, interventional electrophysiology is turned to as a potentially definitive and substrate-related treatment because of antiarrhythmic drug therapy's failure to prevent arrhythmia recurrences and the potential detrimental side effects from drug therapy seen in this particular patient population. Using the experience gained during the past 10 years in the treatment of patients with arrhythmias but without associated structural heart disease, several groups reported their results and difficulties with the application of such therapy to patients with congenital heart defects. In this report, we summarize our hospital's experience with transcatheter radiofrequency current application for treatment of various types of tachyarrhythmias in 139 children and adults with congenital heart defects, emphasizing the current limitations of such therapy and addressing the potential benefits expected from future technology. Patient ages ranged from 5 months to 76 years (mean 25.3 ± 17.7 years), including 56 children and adolescents less than 16 years of age. At least one attempt at surgical palliation or correction was made in 93 patients; the remaining 46 patients had no surgical intervention attempts. A total of 225 different tachycardias were found, 93 of which were based on a congenital arrhythmogenic substrate (e.g., an accessory pathway). Acquired substrates (e.g., scars or myocardial fibrosis) gave rise to the remaining 132 tachycardias. Radiofrequency current ablation (183 sessions) successfully treated 121 of 139 patients. Within a follow-up period of 21 months a recurrence of the intrinsically treated tachycardia was seen in 24 patients (10.7%); 13 of the 24 underwent a successful repeat session. There were no significant procedure-related complications. Young and adult patients with congenital heart disease can be safely and successfully treated for tachycardias with the use of radiofrequency current ablation. Because such treatment meets the specific needs of this patient group, early consideration for this therapy is recommended.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002460010134
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  • 2
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of tocainide in patients with renal dysfunction and during haemodialysis (1983)
    Springer
    European journal of clinical pharmacology 24 (1983), S. 503-507 
    Details
    ISSN: 1432-1041
    Keywords: tocainide ; pharmacokinetics ; renal failure ; antiarrhythmic drug ; haemodialysis ; cirrhosis ; acetyldigoxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The disposition of tocainide was studied in 15 patients with renal dysfunction. In 9 with total renal failure, the plasma half-life ranged from 16.6 to 42.7 h and total plasma clearance from 35 to 94 ml/min. The longest half-lives were found in 1 patient with cirrhosis, 3 taking the enzyme inhibitor allopurinol, and 1 on cimetidine. The mean half-life in the remaining patients was 22.3±4.8 h (±SD). During a 4 h haemodialysis, the half-life in the 9 patients decreased to 8.5±4.6 h, which was calculated to correspond to removal of 25±14% of the drug from the body. In 6 patients with impaired renal function (creatinine clearance 10–55 ml/min) the tocainide half-life ranged from 13.2 to 22.0 h and total plasma clearance from 72 to 122 ml/min. One patient was taking allopurinol and 1 dihydralazine, and the mean half-life in the others was 19.2±4.0 h. The apparent volume of distribution was similar to that found previously in healthy subjects. The results suggest that tocainide elimination is predictably reduced in patients with renal disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609893
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  • 3
    Electronic Resource
    Electronic Resource
    Katheterablation bei Vorfhofflimmern: Schon ein Standardverfahren? (1998)
    Springer
    Herzschrittmachertherapie & Elektrophysiologie 9 (1998), S. S31 
    Details
    ISSN: 1435-1544
    Keywords: Key words Catheter ablation ; atrial fibrillation ; surgical „maze” atrial compartmentalization ; Schlüsselwörter Katheterablation ; Vorhofflimmern ; „Maze“-Operation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Hintergrund : Vorhofflimmern ist mit einer Häufigkeit von 2–4% aller Personen älter als 60 Jahre die am weitesten verbreitete Herzrhythmusstörung. Die Therapie mit Antikoagulantien führt zu einer deutlichen Reduktion der Morbidität und Mortalität bei diesen Patienten. Die Symptome sind sehr vielfältig; die Reaktionen auf die Antiarrhythmika nicht vorhersehbar. Alternative Behandlungsmöglichkeiten zur medikamentösen Therapie sind die Katheterablation mittels Hochfrequenzstrom, der implantierbare Vorhofdefibrillator und die „Maze“-Operation. Ergebnisse verschiedener Studien: Der Einsatz des Vorhofdefibrillators wird derzeit untersucht, obwohl seine klinische Anwendbarkeit fragwürdig ist. Die „Maze“-Operation hat sich als eine effektive kurative Therapie des permanenten und paroxymalen Vorhofflimmerns erwiesen. Allerdings ist dieses Verfahren nur bei ausgewählten Fällen indiziert und sollte nur in speziellen Zentren durchgeführt werden. Die Ziele der Katheterablation sind zweifach: 1) die Herabsetzung und Regulierung der Kammerfrequenz und 2) die primäre Beseitigung des anatomisch-elektrophysiologischen Substrates des Vorhofflimmerns. Der zuerst genannte Aspekt wird durch eine Modifikation der Leitungseigenschaften oder durch Ablation des AV-Knoten mit Implantation eines Schrittmachers erreicht. Bei beiden Methoden wurde von einer klinischen Verbesserung von 80% berichtet. Ein vielversprechendes Verfahren zur kurativen Therapie des Vorhofflimmerns stellt die „Maze“-Operation im Katheterlabor dar. Erste Ergebnisse zeigen, daß die Technik anwendbar ist, obwohl die Effizienz verbessert werden muß. Eine mögliche Anwendung dieser Technik wird erleichtert durch die kürzlich eingeführte computergestützte Mapping-Technik, die eine dreidimensional elektroanatomische Rekonstruktion der Herzkammer erlaubt.
    Notes: Background: Atrial fibrillation is the most common arrhythmia in humans, with a prevalence of 2% to 4% after the age of 60. Anticoagulation therapy has proven effective to reduce morbidity and mortality associated with this arrhythmia. Symptoms vary widely among patients and respond unpredictably to antiarrhythmic drug therapy. Strategies alternative to drug treatment include radiofrequency catheter ablation, implantable atrial defibrillator, and surgical „maze“ atrial compartmentalization. Methods: The implantable atrial defibrillator is presently being investigated as a potential tool, although its clinical applicability remains questionable. Surgical compartmentalization has proven effective to cure atrial fibrillation of the permanent and the paroxysmal type; however, due to its invasivness, this procedure is indicated in very selected cases and performed in few centers. The objective catheter ablation for the therapy of atrial fibrillation is twofold: 1) the reduction and regularization of heart rate; and 2) the primary treatment of the electroanatomical substrate generating and sustaining atrial fibrillation. The former objective is achieved through radiofrequency-induced „modification“ or permanent interruption (together with pacemaker implantation) of the atrioventricular conduction. Clincial improvement in about 80% of cases has been reported with both methods. The primary treatment of atrial fibrillation has been recently proposed based on a replication of the surgical compartmentalization model using catheter techniques. Preliminary results show that the technique is feasible, although its effectiveness must be improved. Possible applications of this technique are facilitated by the recent introduction of a nonfluoroscopic computer-assisted mapping techniques allowing three-dimensional electroanatomical reconstruction of the target chamber.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003990050088
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  • 4
    Electronic Resource
    Electronic Resource
    Arrhythmien als Indikator für eine Reperfusion nach akutem Myokardinfarkt? (1989)
    Springer
    Journal of molecular medicine 67 (1989), S. 1199-1204 
    Details
    ISSN: 1432-1440
    Keywords: Myocardial infarction ; Arrhythmia ; Fibrinolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary For the purposes of the European double blind and randomized study 27 patients with acute myocardial infarction underwent thrombolysis with rt-PA (60 mg over 90 minutes i.v.) or placebo. To evaluate whether arrhythmias, especially ventricular arrhythmias indicate coronary reperfusion after thrombolysis a 24 hour Holter monitoring was performed from the beginning of the rt-PA or placebo infusion. Typical reperfusion arrhythmias were thought to be idioventricular rhythms (rate 〈110/min), ventricular tachycardia (rate 〉110/min) or bradycardic rhythm disturbances (rate 〈50/min). The effect of thrombolysis on reperfusion of the infarct related artery was evaluated 90 minutes after the infusion by coronary angiography. After 90 minutes of rt-PA or placebo infusion in 16/16 patients treated with rt-PA and 2/11 patients, who received placebo, was the infarct atery patent. 16/18 patients with a patent artery presented a total of 105 arrhythmic events. 47% of the arrhythmias obviously due to reperfusion were classified as idioventricular rhythms. In contrast only 3/9 patients with an occluded infarct artery presented 25 arrhythmic events. The time of occurence was not different during the running rt-PA infusion compared to placebo. The following interval up to 24 hours showed no difference in incidence and type of the arrhythmias. No relationship was found between reperfusion arrhythmias and salvage of myocardium during 90 minutes of rt-PA or placebo infusion. It is concluded: 1. 89%, i.e. in 16 patients with a patent infarct artery reperfusion arrhythmias were found within 90 minutes after the onset of the infusion therapy. 2. Reperfusion arrhythmias seemed to be independant of myocardial salvage. 3. Absence of idioventricular rhythms or ventricular tachycardia is highly suggestive of an occluded infarct vessel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01716207
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  • 5
    Electronic Resource
    Electronic Resource
    Anatomische Verteilung, Leitungseigenschaften und Rezidivverhalten nach Ablation von multiplen im Vergleich zu singulären akzessorischen Leitungsbahnen (1997)
    Springer
    Zeitschrift für Kardiologie 86 (1997), S. 221-230 
    Details
    ISSN: 1435-1285
    Keywords: Key words Accessory pathway — radiofrequent current — catheter ablation — comparative study ; Schlüsselwörter Akzessorische Leitungsbahn — Hochfrequenzstrom — Katheterablation — vergleichende Untersuchung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary In 1076 consecutive patients referred for radiofrequency current catheter ablation, the anatomical distribution and conduction properties of accessory pathways (APs) as well as the mode of recurrence after ablation were retrospectively analyzed and compared in patients with multiple and single APs. Except for 17 patients with Ebstein's anomaly, the prevalence of patients of multiple APs in this cohort was 5.4%. Patients with multiple APs, as opposed to patients with a single AP, had significantly more often APs located on the right free wall (23% versus 10%) and — since the prevalence of septal APs was identical in both groups — less frequently APs located on the left free wall (44% versus 56%). Also, concealed APs were significantly more often encountered in patients with multiple APs (45% versus 24%). Recurrence of conduction across an AP which had presumably been ablated was observed in both groups with statistically equal incidence of 〈 5%. In 11 patients with multiple APs, the additional AP was only found at the repeat session. These "new" APs were mostly concealed (9 out of 11) and necessitated an intervention predominantly late after the initial ablation session. Intermittent concealed conduction appears to be a likely explanation for this phenomenon. Patients with multiple APs exhibit a higher incidence of right free-wall and concealed APs, yet they stand the same, approximately 95%, chance of cure as do patients with a single AP. Nearly 25% of repeat sessions in patients initially thought to have a single AP are caused by the late manifestation of an additional AP.
    Notes: Zusammenfassung In dieser Studie wurden die Befunde von 1076 konsekutiven Patienten, bei denen eine Hochfrequenzstrom-Katheterablation von akzessorischen Leitungsbahnen durchgeführt worden war, retrospektiv unter der Fragestellung analysiert, ob es hinsichtlich der anatomischen Verteilung und den Leitungseigenschaften der akzessorischen Bündel sowie dem Rezidivverhalten nach Ablation Unterschiede zwischen Patienten mit multiplen Leitungsbahnen und Patienten mit singulärer Leitungsbahn gibt. Unter Ausschluß von 17 Patienten mit Ebsteinscher Anomalie betrug der Anteil von Patienten mit multiplen Leitungsbahnen im untersuchten Kollektiv 5,4%. Bei diesen Patienten fanden sich im Unterschied zu Patienten mit singulärer Leitungsbahn statistisch signifikant häufiger akzessorische Bahnen an der rechten freien Wand (23% gegenüber 10%) und — da der Anteil septaler Leitungsbahnen in beiden Patientengruppen gleich groß war — entsprechend weniger häufig akzessorische Leitungsbahnen an der linken freien Wand (44% gegenüber 56%). Ebenso war der Anteil von verborgenen akzessorischen Leitungsbahnen bei Patienten mit multiplen Leitungsbahnen signifikant erhöht (45% gegenüber 24%). Rezidivierende Leitung über eine akzessorische Faser, die vermeintlich erfolgreich unterbrochen wurde, fand sich in beiden Patientengruppen mit einer statistisch gleichen Häufigkeit von unter 5%. Bei 11 Patienten mit multiplen Leitungsbahnen wurde die zusätzliche Leitungsbahn erst im Rahmen einer Zweitprozedur gefunden. Diese "neuen" Leitungsbündel leiteten zumeist nur retrograd (9 von 11) und manifestierten sich erst Tage bis Monate nach der initialen Ablationssitzung. Intermittierende retrograde akzessorische Leitung bietet sich als wahrscheinliche Erklärung für dieses Phänomen an. Trotz der größeren Häufigkeit von akzessorischen Bündeln an der rechten freien Herzwand und von ausschließlich retrograden Leitungseigenschaften der akzessorischen Fasern besteht bei Patienten mit multiplen Leitungsbahnen dieselbe, etwa 95%ige Heilungswahrscheinlichkeit wie bei Patienten mit singulärer Leitungsbahn. Knapp 25% der Zweitprozeduren bei Patienten, die sich zur Ablation einer singulären akzessorischen Leitungsbahn vorstellten und bei denen es zu einem Arrhythmierezidiv kam, sind durch eine initial nicht nachweisbare zusätzliche Leitungsbahn bedingt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003920050054
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  • 6
    Electronic Resource
    Electronic Resource
    Durchflußzytometrisch nachgewiesene Aktivierung von Thrombozyten im Verlauf der Rotablation (2000)
    Springer
    Zeitschrift für Kardiologie 89 (2000), S. 15-20 
    Details
    ISSN: 1435-1285
    Keywords: Key words Flow cytometry – platelets – antigen – rotablation – PTCA ; Schlüsselwörter Durchflußzytometrie – Thrombozyten – Antigen – Rotablation – PTCA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Zu den bis heute erfolgslimitierenden Faktoren der interventionellen kardiologischen Verfahren zählen die akute und subakute Okklusion und die Restenose. Bei den genannten Komplikationen sind aktivierte Thrombozyten maßgeblich beteiligt. In dieser Studie wurde mittels der Durchflußzytometrie der Einfluß der Rotablation auf die Expression von Thrombozytenantigenen analysiert. Als Kontrollgruppe wurde ein Patientenkollektiv mit alleiniger PTCA untersucht. Es wurden die Fluoreszenzexpressionen der Strukturantigene CD41a (GPIIb–IIIa) und CD42b (GPIb-V–IX), der aktivierungsabgängigen Epitope CD62p (P-Selektin, PADGEM, GMP-140) und CD63 (GP53) und die Bindung von Fibrinogen vorher, direkt nach der Prozedur und dreißig Minuten nach Ende der Prozeduren gemessen. CD41a und CD42b zeigten keine signifikanten Veränderungen im Verlauf von PTCA oder Rotablation (PTCA: CD41a p=0,8 und 0,9; CD42b p=0,5 und 0,2; Rotablation: CP41a p=0,2 und 0,2; CD42b p=0,4 und 0,1). Direkt im Anschluß an die PTCA bzw. Rotablation ließen sich signifikante Anstiege der MCFI-Werte (mean channel fluorescence intensity) von CD62p, CD63 und der Bindung von Fibrinogen nachweisen (p〈0,05). Dreißig Minuten nach Ende der Verfahren zeigten sich signifikante Anstiege der MCFI bei der PTCA (CD62p, CD63 und Fibrinogenbindung, alle p〈0,05), nicht aber bei der Rotablation (CD62p p=0,1; CD63 p=0,9; Bindung von Fibrinogen p=0,5). Die MCFI-.Werte für CD62p und die Bindung von Fibrinogen waren bei der Rotablation höher als bei der PTCA. Unsere Ergebnisse zeigen, daß es bei der Rotablation zur signifikanten Thrombozytenaktivierung kommt, die stärker ausgeprägt ist als bei alleiniger PTCA. Zum Nachweis der Aktivierung ist die Durchflußzytometrie als sensitives, spezifisches, multiparametrisches Meßverfahren geeignet. Die Aktivierung von Thrombozyten ist Teil einer komplexen Kaskade, die nach einer Intervention im behandelten Koronargefäß abläuft und zu einer überschießenden vaskulär-molekulären Entzündungsreaktion und klinischen Problemen bei einigen Patienten führen kann.
    Notes: Summary Acute occlusion and subacute restenosis of the coronary artery are still the limiting factors of the otherwise successful interventional cardiology. Platelets and especially activated platelet populations play a key role concerning these typical and sometimes fatal complications. In this study we used flow-cytometry to determine the influence of the modern interventional technique of rotablation on platelet antigens and their possible alteration. A PTCA control group was included. We analyzed the fluorescence expression of structural antigens CD41a (GPII–IIIa) and CD42b (GPIb-V–IX), and of the activation-dependent antigens CD62p (P-selectin, PADGEM, GMP-140) and CD63 (GP53). Furthermore we analyzed the binding of fibrinogen to the platelet flow-cytometrically. CD41a and CD42b did not show significant alternations in fluorescence before, directly after and thirty minutes after finishing PTCA and rotablation (PTCA: CD41a p=0.8 and 0.9; CD42b p=0.5 and 0.2; rotablation: CD41a p=0.2 and 0.2; CD42b p=0.4 and 0.1). But platelet activation could be detected directly after PTCA and rotablation measuring the mean channel fluorescence intensity (MCFI) of CD62p, CD63 and fibrinogen binding (all p〈0.05). Thirty minutes after finishing the procedures there were again significant changes in MCFI in PTCA (CD62p, CD63, fibrinogen binding; all p〈0.05), but not in rotablation (CD62p p=0.1; CD63 p=0.9; fibrinogen binding p=0.5). But MCFI for CD62p and fibrinogen binding in rotablation was higher than in PTCA. The results of our study show that rotablation also induces significant platelet activation that is higher than in PTCA alone. Flow cytometry is a sensitive and specific, multiparametric tool in establishing platelet activation. The individual platelet activation process is part of a complex cascade of events happening in the rotablated coronary segment leading to a vascular-molecular inflammatory process and consecutive clinical problems in some patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003920050003
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