Papers by Thomas Klingenheben
Herzschrittmachertherapie + Elektrophysiologie, 2014
Am 12. Februar verstarb 100-jährig in Newport-Beach Bruce E. Del Mar, der zusammen mit Norman Hol... more Am 12. Februar verstarb 100-jährig in Newport-Beach Bruce E. Del Mar, der zusammen mit Norman Holter (1914-1983) ein Pionier der telemetrischen EKG-Aufzeichnung und Entwicklung der ersten kommerziell verfügbaren Langzeit-EKG-Geräte war. Geboren 1913 in Pasadena, CA, wurde er einer der sicher vielseitigsten Erfinder seiner Zeit, nicht nur im Bereich der Medizin-, sondern auch der Flugzeug-und Raketentechnik. Von seinem umfangreichen Schaffen zeugen insgesamt über 200 Firmenpatentevon denen er 36 persönliche Patente zwischen 1945 und 2003 erwarb-das letzte als 90-Jähriger für einen "ambulatory physio-kinetic monitor". Tatsächlich wandte Del Mar sich aber nach dem Ingenieursstudium aufgrund seiner Begeisterung für die Fliegerei zunächst der Flugzeugtechnik zu. Während seiner Zeit bei Douglas entwickelte er die Methodik zum Druckausgleich
Herzschrittmachertherapie und Elektrophysiologie, 1998
Medicine & Science in Sports & Exercise, 2001
Journal of the American College of Cardiology, 2003
OBJECTIVES This study was designed to evaluate the ability of microvolt-level T-wave alternans (M... more OBJECTIVES This study was designed to evaluate the ability of microvolt-level T-wave alternans (MTWA) to identify prospectively patients with idiopathic dilated cardiomyopathy (DCM) at risk of ventricular tachyarrhythmic events and to compare its predictive accuracy with that of conventional risk stratifiers. BACKGROUND Patients with DCM are at increased risk of sudden death from ventricular tachyarrhythmias. At present, there are no established methods of assessing this risk. METHODS A total of 137 patients with DCM underwent risk stratification through assessment of MTWA, left ventricular ejection fraction, baroreflex sensitivity (BRS), heart rate variability, presence of nonsustained ventricular tachycardia (VT), signal-averaged electrocardiogram, and presence of intraventricular conduction defect. The study end point was either sudden death, resuscitated ventricular fibrillation, or documented hemodynamically unstable VT. RESULTS During an average follow-up of 14 Ϯ 6 months, MTWA and BRS were significant univariate predictors of ventricular tachyarrhythmic events (p Ͻ 0.035 and p Ͻ 0.015, respectively). Multivariate Cox regression analysis revealed that only MTWA was a significant predictor. CONCLUSIONS Microvolt-level T-wave alternans is a powerful independent predictor of ventricular tachyarrhythmic events in patients with DCM.
Journal of the American College of Cardiology, 1998
Objectives. The purpose of this study was to determine the precise incidence, therapeutic options... more Objectives. The purpose of this study was to determine the precise incidence, therapeutic options and prognostic implications of electrical storm in patients with transvenous implantable cardioverter-defibrillator (ICD) systems. Background. Approximately 50% to 70% of patients treated with an ICD receive appropriate device-based therapy within the first 2 years. Most arrhythmic events require only one appropriate ICD firing for termination. However, some patients receive multiple appropriate shocks during a short period of time, a condition referred to as "arrhythmic or electrical storm." Methods. This prospectively designed observational study comprised 136 recipients of transvenous ICDs who were followed for 403 ؎ 242 days. Electrical storm was defined as ventricular tachycardia or fibrillation resulting in device intervention > ؊ 3 times during a single 24-h period. Results. During follow-up, 57/136 patients (42%) received appropriate ICD therapy. Electrical storm occurred in 14/136 patients (10%) at an average of 133 ؎ 135 days after ICD implan-tation. The mean number of arrhythmic episodes constituting electrical storm was 17 ؎ 17 (range: 3 to 50; median 8) per patient. In 12 patients, electrical storm required hospital admission. The arrhythmia cluster could be terminated by a combined therapy with -blockers and intravenous amiodarone whereas class I antiarrhythmic drugs were only occasionally successful. The cumulative probability of survival as estimated by the Kaplan-Meier method showed that patients with an episode of electrical storm did not have a worse outcome compared to those without such an event. Conclusions. Electrical storm represents a frequent event in patients treated with modern ICDs. It occurs most commonly late after ICD implantation and can be managed by combined therapy with -blockers and amiodarone. Electrical storm does not independently confer increased mortality.
Circulation, 2006
Background— Previous studies that assessed the effects of β-blockers in preventing vasovagal sync... more Background— Previous studies that assessed the effects of β-blockers in preventing vasovagal syncope provided mixed results. Our goal was to determine whether treatment with metoprolol reduces the risk of syncope in patients with vasovagal syncope. Methods and Results— The multicenter Prevention of Syncope Trial (POST) was a randomized, placebo-controlled, double-blind, trial designed to assess the effects of metoprolol in vasovagal syncope over a 1-year treatment period. Two prespecified analyses included the relationships of age and initial tilt-test results to any benefit from metoprolol. All patients had >2 syncopal spells and a positive tilt test. Randomization was stratified according to ages <42 and ≥42 years. Patients received either metoprolol or matching placebo at highest-tolerated doses from 25 to 200 mg daily. The main outcome measure was the first recurrence of syncope. A total of 208 patients (mean age 42±18 years) with a median of 9 syncopal spells over a media...
Circulation, 1994
BACKGROUND The autonomic nervous system has been demonstrated to play a decisive role in the gene... more BACKGROUND The autonomic nervous system has been demonstrated to play a decisive role in the genesis of sudden cardiac death. The loss of protective vagal reflexes, in particular, appears to be associated with an increased incidence of malignant ventricular tachyarrhythmias. Two clinically applicable methods for assessment of cardiac autonomic control have been developed: determination of heart rate variability and evaluation of baroreflex sensitivity. METHODS AND RESULTS To compare the potential predictive value of both methods, two groups of patients were studied. Group 1 comprised 14 postinfarction patients who had experienced at least one episode of ventricular fibrillation or sustained ventricular tachycardia and who were studied after this event. Group 2 consisted of 14 postinfarction patients without tachyarrhythmic events after their infarct. Both groups were carefully matched with respect to age, sex, infarct location, extent of coronary artery disease, left ventricular eje...
Circulation, 2000
Background —The stratification of post–myocardial infarction (MI) patients at risk of sudden card... more Background —The stratification of post–myocardial infarction (MI) patients at risk of sudden cardiac death remains important. The aim of the present study was to assess the prognostic value of novel T-wave morphology descriptors derived from resting 12-lead ECGs. Methods and Results —In 280 consecutive post-MI patients, a 12-lead ECG was recorded before discharge, optically scanned, and digitized. For the present study, 5 T-wave morphology descriptors were automatically calculated after singular value decomposition of the ECG signal. The total cosine R-to-T (TCRT [describes the global angle between repolarization and depolarization wavefront]) and the T-wave loop dispersion were univariately associated ( P =0.0002 and P <0.002, respectively, U test) with 27 prospectively defined clinical events in 261 patients (mean follow-up 32±10 months). Kaplan-Meier event probability curves for strata above and below the median confirmed the strong risk discrimination by TCRT and T-wave loop ...
Circulation, 1998
Background —Risk stratification by means of analysis of QT dispersion (QTD) in the 12-lead surfac... more Background —Risk stratification by means of analysis of QT dispersion (QTD) in the 12-lead surface ECG is under intense investigation in various patient populations. The aim of the present prospective study was to evaluate the prognostic value of QTD and other ECG variables reflecting dispersion of ventricular repolarization in comparison with established risk stratifiers during long-term follow-up in a large cohort of post–myocardial infarction patients treated according to contemporary therapeutic guidelines. Methods and Results —In 280 consecutive infarct survivors, the 12-lead ECG was optically scanned and digitized for analysis of QTD (QT max −QT min ) and 25 other repolarization variables, including recently developed and validated parameters such as the T peak–to–T end interval and the area under the T wave. In addition, a variety of established risk stratifiers were assessed. After a mean follow-up period of 32±10 months, 30 patients reached one of the prospectively defined ...
The American Journal of Cardiology, 2013
Herzschrittmachertherapie + Elektrophysiologie
Herzschrittmachertherapie + Elektrophysiologie
Cardiology research and practice, 2016
Herzschrittmachertherapie Und Elektrophysiologie, 2005
ABSTRACT Die Prognose des prhospitalen Herzstillstandes aufgrund von Kammerflimmern entscheidet s... more ABSTRACT Die Prognose des prhospitalen Herzstillstandes aufgrund von Kammerflimmern entscheidet sich innerhalb der ersten Minuten, da das berleben zur Krankenhausentlassung mit jeder Minute, um welche eine effektive Reanimation versptet einsetzt, um etwa 10% abnimmt [1]. Insofern kommt neben der schnellen Erreichbarkeit durch ein suffizientes Rettungsteam einer frhzeitigen Defibrillation eine Schlsselstellung zu. Der Nutzen (halb-)automatischer externer Defibrillatoren in diesem Zusammenhang ist durch klinische Studien mehrfach geprft. Weitere Aspekte der Reanimation bei Kammerflimmern werden unverndert kontrovers diskutiert wie der Nutzen von Antiarrhythmika (insbesondere Amiodaron) und die Anwendung von Vasopressin im Rahmen der Reanimation. In der vorliegenden bersicht sollen daher diese Aspekte schwerpunktmig behandelt werden, ebenso wie auch auf die jngste berarbeitung der ILCOR-Leitlinien zur kardiopulmonalen Reanimation [2] eingegangen wird, die entsprechende nderungen der europischen Leitlinien des ERC (European Resuscitation Council) nach sich gezogen hat.Prognosis of prehospital cardiac arrest due to ventricular fibrillation is dependent on the first minutes, as survival decreases by 10% for each minute by which resuscitation attempts are delayed. Thus, early defibrillation plays a key role in improving outcome of cardiac arrest victims. The effectiveness of automated external defibrillators (AEDs) in this setting has been proven by several clinical trials. There remains controversy with regard to using AEDs in the in-hospital setting, as well as the approach of “public access” defibrillation. Whereas the use of intravenous antiarrhythmic drugs, particularly amiodarone, remains controversial, new data support the use of vasopressine instead of epinephrine as vasopressor drug in cardiac arrest patients. The present review aims to focus on the above mentioned aspects as well as on the changes to the present ILCOR guidelines which have led to modification of the resuscitation guidelines of the European Resuscitation Council (ERC).
Journal of the American College of Cardiology, Jul 5, 2016
There is limited evidence whether being on fludrocortisone prevents vasovagal syncope. The author... more There is limited evidence whether being on fludrocortisone prevents vasovagal syncope. The authors sought to determine whether treatment with fludrocortisone reduces the proportion of patients with recurrent vasovagal syncope by at least 40%, representing a pre-specified minimal clinically important relative risk reduction. The multicenter POST 2 (Prevention of Syncope Trial 2) was a randomized, placebo-controlled, double-blind trial that assessed the effects of fludrocortisone in vasovagal syncope over a 1-year treatment period. All patients had >2 syncopal spells and a Calgary Syncope Symptom Score >-3. Patients received either fludrocortisone or matching placebo at highest tolerated doses from 0.05 mg to 0.2 mg daily. The main outcome measure was the first recurrence of syncope. The authors randomized 210 patients (71% female, median age 30 years) with a median 15 syncopal spells over a median of 9 years equally to fludrocortisone or placebo. Of these, 96 patients had ≥1 sy...
Herzschrittmachertherapie Und Elektrophysiologie, 2003
ABSTRACT Since the publication of the two MADIT trials, the implantable cardioverter defibrillato... more ABSTRACT Since the publication of the two MADIT trials, the implantable cardioverter defibrillator has moved from a tool for secondary prevention to a primary preventive strategy against sudden cardiac death in high risk patients with coronary artery disease. However, the general use of the ICD in post myocardial infarction patients with impaired left ventricular function continues to be a matter of debate, particularly in the light of costs associated with this therapy. Accordingly, there is the continued need to refine risk stratification by noninvasive means in patients prone to sudden cardiac death. This article briefly summarizes results obtained by the most promising methods such as measures of autonomic tone or analysis of microvolt level T-wave alternans.Seit Publikation der beiden MADIT-Studien hat sich die Therapie mit implantierbaren Defibrillatoren von der reinen Sekundrprvention gewandelt zu einem effektiven Instrument der Primrprophylaxe des pltzlichen Herztodes bei Patienten mit frherem Myokardinfarkt und deutlich reduzierter systolischer linksventrikulrer Funktion. Die generelle Anwendung dieser Therapie bei Postinfarktpatienten mit einer LVEF30% wird jedoch derzeit kontrovers diskutiert, insbesondere auch aufgrund der mit dieser Therapie verbundenen hohen Kosten. Daher besteht auch weiterhin die Notwendigkeit, die nichtinvasive Risikostratifikation mittels elektrokardiographischer Marker bei Patienten mit erhhtem Risiko des pltzlichen Herztodes zu verfeinern. In diesem Kontext fokussiert die vorliegende bersicht auf diejenigen Ergebnisse, die mit den vielversprechendsten Methoden erhoben worden sind, wie beispielsweise Parametern des autonomen Nervensystems oder den T-Wellen-Alternans im Mikrovoltbereich.
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Papers by Thomas Klingenheben