Dirk Böcker

University of Münster, Münster, North Rhine-Westphalia, Germany

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Publications (127)611.68 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This article aims to give an overview over important articles in the field of implantable cardioverter defibrillator (ICD) therapy in 2012. Important publications concern analyses on therapy efficacy and safety of the subcutaneous ICD, gender-specific differences in the complication rate and prognosis after ICD implantation, the necessity of intraoperative testing of the defibrillation threshold and the impact of preventive measures to reduce ICD therapies on prognosis after device implantation. The relevance of the study findings for daily clinical practice is briefly discussed.
    Herzschrittmachertherapie & Elektrophysiologie 04/2013;
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    ABSTRACT: Riata® and Riata ST® implantable cardioverter defibrillator (ICD) leads (St. Jude Medical, Sylmar, CA) show an increased incidence of insulation defects, particularly "inside-out" lead fracture where inner, separately insulated cables penetrate through the surrounding silicone of the lead body. The exact incidence of Riata® lead problems is not clear and seems to range between 2-4% per year in the first 5 years after implantation according to new registry data. We recommend beyond a detailed information the following care of patients with Riata® and Riata ST® leads: 1) Activation of automatic ICD alerts, 2) remote monitoring with automatic daily alerts whenever possible, 3) monthly ICD controls in patients at high risk (pacemaker dependency, history of ventricular tachyarrhythmias) and high or moderate lead-related risk (8F, 7F single coil), 3-monthly controls in moderate patient and lead-related risk, 3 to 6-monthly controls in low patient and lead-related risk (no bradycardia, no history of ventricular tachyarrhythmia). Every ICD control should include meticulous analysis of oversensing artifacts in stored electrograms (EGMs) of sustained and non-sustained ventricular tachyarrhythmias and registration of EGMs during provocation testing (pectoral muscle activity, arm movements). If electrical abnormalities are observed, reoperation with addition of a new ICD lead is recommended; lead extraction only if indicated according to current guidelines. Fluoroscopy should only be performed if electrical abnormalities are found by an experienced electrophysiologist and a high frame rate and resolution. Management of fluoroscopic abnormalities in the absence of electrical abnormalities is not clear. Therefore, routine fluoroscopy of patients with Riata® leads without electrical abnormalities is not recommended.
    Herzschrittmachertherapie & Elektrophysiologie 08/2012; 23(2):107-15.
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    ABSTRACT: Inadäquate Therapien implantierbarer Kardioverter-Defibrillatoren infolge supraventrikulärer Tachykardien stellen weiterhin die häufigste Komplikation der ICD-Therapie dar. Die Einführung des Morphologie (MD)-Kriteriums verspricht eine Verbesserung der Spezifität in der Tachyarrhythmieerkennung bei Erhalt der Sensitivität. Ziel dieser multizentrischen Studie war die systematische Analyse von Sensitivität und Spezifität des MD-Kriteriums in kombinierter Anwendung mit den Kriterien Stabilität und Frequenzsprung (Sudden Onset) bei spontanen Episoden ventrikulärer und supraventrikulärer Tachykardien. Bei 259 Patienten wurden nach ICD-Implantation 787 gespeicherte Episoden bei 74 Patienten mit erhältlichem Speicherelektrogramm während einer Nachbeobachtungszeit von 359±214 Tagen analysiert. Bei nominaler Programmierung des MD-Kriteriums mit ≥60% ergaben sich unter Berücksichtigung aller Episoden eine Sensitivität/Spezifität der Detektion von 82,6%/77,2%. Bei getrennter Analyse von Sinustachykardien, Vorhofflimmern und Vorhofflattern betrug die Spezifität 80,6%, 69,6% und 75%. Bei Patienten mit primär adäquater MD-Detektion waren Sensitivität und Spezifität mit 95,8%/91,7% deutlich verbessert. Bei nominaler Programmierung des Sudden Onset-Kriteriums mit <100ms und des Stabilitätskriteriums mit <50ms ergaben sich für die Kombination MD- und Sudden-Onset-Kriterium bzw. MD- und Stabilitätskriterium eine Sensitivität/Spezifität von 96,2%/52,2% bzw. 94,4%/63,8%. Die Anwendung des MD-Detektionskriteriums lässt in der kombinierten Anwendung mit den herkömmlichen erweiterten Kriterien wie Sudden Onset- und Stabilitätskriterien eine deutlich verbesserte Spezifität der ICD-Therapie erwarten. The high incidence of inappropriate therapies due to supraventricular tachycardia remains a major unsolved problem of the implantable cardioverter defibrillator. A new morphology discrimination (MD) algorithm has been introduced to improve specificity of ICD therapy without loss of sensitivity. It was the aim of this study to systematically analyze sensitivity and specificity of the MD criterion in combination with the enhanced detection criteria sudden onset and rate stability in the detection of ventricular and supraventricular tachycardia. After ICD implantation in 259 patients, 787 detected episodes in 74 patients with available stored electrograms were documented during a follow-up period of 359±214 days. With a nominal programming of the MD algorithm at ≥60%, sensitivity and specificity for all episodes were 82.6%/77.2%. For sinus tachycardia, atrial fibrillation and atrial flutter the specificities were 80.6%, 69.6% and 75%, respectively. In patients with primarily appropriate MD detection, sensitivity and specificity significantly improved to 95.8%/91.7%. Programming the sudden onset criterion with <100ms and the stability criterion with <50ms, sensitivity and stability of the combined application of the MD algorithm and sudden onset and MD algorithm and stability were 96.2%/52.2% and 94.4%/63.8%, respectively. The MD criterion in combination with other enhanced detection criteria might significantly improve specificity of tachyarryhthmia detection of ICD therapy. Schlüsselwörter Implantierbarer Defibrillator – Detektionskriterien – Morphologie – Stabilität – Sudden OnsetKey words Implantable defibrillator – enhanced detection criteria – morphology – stability – sudden onset
    Zeitschrift für Kardiologie 04/2012; 89(11):1019-1025. · 0.97 Impact Factor
  • Dirk Böcker, Martin Borggrefe
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    ABSTRACT: The past decade has seen a remarkable change in the approach to treating life-threatening arrhythmias. The efficacy and safety of antiarrhythnmic agents has been questioned and the confidence in their utility has eroded. Until publication of the CAST study (Cardiac Arrhythmia Suppression Trial) (1), a prevailing concept was that arrhytlunias could be controlled by drugs that slow conduction or suppress automaticity, goals well served by the sodium-channel blocking drugs. Unexpectedly, the CAST trial (2) showed that treatment with sodium channel blocking agents including encainide, flecainide, and morizicine was associated with substantial increases in mortality. Only 3 years later, the ESVEM trial (Electrophysiologic Study Versus Electrocardiographic Monitoring) (2) demonstrated that d,l-sotalol was superior to several class I antiarrhythmic agents. In the wake of these trials, the emphasis shifted towards antiarrhythmic agents that cause selective prolongation of repolarization without slowing conduction. However, the development of pure class-III antiarrhythmic drugs was stopped by many pharmaceutical companies after completion of the SWORD study (3) (Survival With ORal D-Sotalol) became available. This trial was designed to show that a pure potassiumchannel-blocking action reduces all-cause mortality in patients with previous myocardial infarction and left ventricular dysfunction. It was prematurely terminated when an interim analysis showed increased mortality in patients assigned to d-sotalol.
    07/2011: pages 1-14;
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    ABSTRACT: Intracardiac electrograms (IEGMs) recorded by implantable cardioverter-defibrillators (ICDs) are essential for arrhythmia diagnosis and ICD therapy assessment. Short IEGM snapshots showing 3-10 s before arrhythmia detection were added to the Biotronik Home Monitoring system in 2005 as the first-generation IEGM Online. The RIONI study tested the primary hypothesis that experts' ratings regarding the appropriateness of ICD therapy based on IEGM Online and on standard 30 s IEGM differ in <10% of arrhythmia events. A total of 619 ICD patients were enrolled and followed for 1 year. According to a predefined procedure, 210 events recorded by the ICDs were selected for evaluation. Three expert board members rated the appropriateness of ICD therapy and classified the underlying arrhythmia using coded IEGM Online and standard IEGM to avoid bias. The average duration of IEGM Online was 4.4±1.5 s. According to standard IEGM, the underlying arrhythmia was ventricular in 135 episodes (64.3%), supraventricular in 53 episodes (25.2%), oversensing in 17 episodes (8.1%), and uncertain in 5 episodes (2.4%). The expert board's rating diverged between determinable IEGM Online tracings and standard IEGM in 4.6% of episodes regarding the appropriateness of ICD therapy (95% CI up to 8.0%) and in 6.6% of episodes regarding arrhythmia classification (95% CI up to 10.5%). By enabling accurate evaluation of the appropriateness of ICD therapy and the underlying arrhythmia, the first-generation IEGM Online provided a clinically effective basis for timely interventions and for optimized patient management schemes, which was comparable with current IEGM recordings.
    Europace 02/2011; 13(2):221-9. · 3.05 Impact Factor
  • Wiener klinische Wochenschrift 01/2010; 122(1-2):22. · 0.79 Impact Factor
  • Europace 01/2010; 11. · 3.05 Impact Factor
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    ABSTRACT: Tako-Tsubo cardiomyopathy (TT-CM), also called stress-induced cardiomyopathy or transient left ventricular (LV) apical ballooning syndrome, is characterized by transient apical or midventricular LV dysfunction that mimics myocardial infarction, but in the absence of significant coronary artery disease. The onset of TT-CM is typically triggered by an acute medical illness or by intense emotional, psychological, or physical stress. During the acute phase, a disturbed repolarization with QT prolongation in the surface ECG is frequently obvious. Despite the generally good prognosis of TT-CM, severe clinical courses have been reported due to the depressed LV function with cardiogenic shock or malignant tachyarrhythmias. We report an unusual presentation of a patient with TT-CM and recurrent episodes of torsades de pointes tachyarrhythmias. In this patient, we identified pre- and coexisting congenital long QT syndrome and severe cardiac hypertrophy--all of them associated with disturbed myocardial repolarization and predisposed the patient to malignant tachyarrhythmias.
    Europace 03/2009; 11(6):820-2. · 3.05 Impact Factor
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    ABSTRACT: The number of cardioverter/defibrillator (ICD) implantations has been steadily increasing; thus, ICD lead-associated complications are an important issue. No clear recommendations for the diagnosis and management are available. This article gives an overview of how to diagnose and manage an ICD lead defect. Possible therapeutic options are discussed by reviewing the literature.
    Herzschrittmachertherapie & Elektrophysiologie 01/2009; 19(4):169-80.
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    ABSTRACT: The long-QT syndromes (LQTS) are inherited electrical cardiomyopathies characterized by prolonged ventricular repolarization and ventricular arrhythmias. Several genetic reports have associated defects in LQTS-causing genes with atrial fibrillation (AF). We therefore studied whether atrial arrhythmias occur in patients with LQTS under daily-life conditions. We systematically assessed atrial arrhythmias in LQTS patients and matched controls using implanted defibrillators or pacemakers as monitors of atrial rhythm in a nested case-control study. Twenty-one LQTS patients (3 male; 39 +/- 18 years old; 18 on beta blocker, ICD therapy duration 6.3 +/- 2.7 years; 4 LQT1, 6 LQT2, 2 LQT3) were matched to 21 control subjects (13 male; 50 +/- 19 years old; 3 on beta blocker; pacemaker therapy duration 8.5 +/- 5.5 years; 19 higher-degree AV block, 2 others). LQTS patients were identified by a systematic search of the LQTS patient databases in Münster and Munich. One-third (7 of 21) of the LQTS patients developed self-terminating atrial arrhythmias (atrial cycle lengths <250 ms). Only one control patient developed a single episode of postoperative AF (P < 0.05 vs LQTS). LQTS patients at high risk for ventricular arrhythmias may develop short-lasting atrial arrhythmias under daily-life conditions, suggesting that prolonged atrial repolarization may contribute to the initiation of AF.
    Journal of Cardiovascular Electrophysiology 10/2008; 20(4):401-7. · 3.48 Impact Factor
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    ABSTRACT: We performed a randomized, double blind, crossover study of cardiac contractility modulation (CCM) signals in heart failure patients. One hundred and sixty-four subjects with ejection fraction (EF) < 35% and NYHA Class II (24%) or III (76%) symptoms received a CCM pulse generator. Patients were randomly assigned to Group 1 (n = 80, CCM treatment 3 months, sham treatment second 3 months) or Group 2 (n = 84, sham treatment 3 months, CCM treatment second 3 months). The co-primary endpoints were changes in peak oxygen consumption (VO2,peak) and Minnesota Living with Heart Failure Questionnaire (MLWHFQ). Baseline EF (29.3 +/- 6.7% vs. 29.8 +/- 7.8%), VO2,peak (14.1 +/- 3.0 vs. 13.6 +/- 2.7 mL/kg/min), and MLWHFQ (38.9 +/- 27.4 vs. 36.5 +/- 27.1) were similar between the groups. VO2,peak increased similarly in both groups during the first 3 months (0.40 +/- 3.0 vs. 0.37 +/- 3.3 mL/kg/min, placebo effect). During the next 3 months, VO2,peak decreased in the group switched to sham (-0.86 +/- 3.06 mL/kg/min) and increased in patients switched to active treatment (0.16 +/- 2.50 mL/kg/min). MLWHFQ trended better with treatment (-12.06 +/- 15.33 vs. -9.70 +/- 16.71) during the first 3 months, increased during the second 3 months in the group switched to sham (+4.70 +/- 16.57), and decreased further in patients switched to active treatment (-0.70 +/- 15.13). A comparison of values at the end of active treatment periods vs. end of sham treatment periods indicates statistically significantly improved VO2,peak and MLWHFQ (P = 0.03 for each parameter). In patients with heart failure and left ventricular dysfunction, CCM signals appear safe; exercise tolerance and quality of life (MLWHFQ) were significantly better while patients were receiving active treatment with CCM for a 3-month period.
    European Heart Journal 04/2008; 29(8):1019-28. · 14.72 Impact Factor
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    ABSTRACT: Earlier ICD therapy included an electrophysiological study (EPS), an extensive defibrillation threshold test (DFT), and a pre-discharge test. Now that ICD-therapy is widely accepted, an EPS is no longer performed in most patients, extensive DFT-tests have been reduced to a minimum of two effective shocks and discharge tests have been discarded in most centres. However, it has never been demonstrated prospectively that this simplification is safe. The Quick-Implantable-Defibrillator (Quick-ICD) Trial was a prospective multi-centre trial, which randomized patients, who had survived a cardiac arrest (SCD) or an unstable ventricular tachycardia (VT), to two different clinical strategies: (a) The extensive strategy included an EPS, an extensive DFT-test, and a pre-discharge test; (b) In the simplified approach (quick strategy) the ICD was implanted without an EPS and a pre-discharge test. Two effective shocks during implantation at 21 J were sufficient. The primary endpoint of this trial was a cluster of adverse events related to the diagnostic approach and to ICD-therapy. One hundred and ninety patients were included, 97 randomized to the extensive-, 93 to the quick strategy. Mean follow-up was 12 +/- 7 months. Twenty-seven patients reached the endpoint in the quick group and 32 in the extensive group. During follow-up, the event-free survival was equal in the two study arms (test for equivalence, P = 0.0044). The initial hospital stay was significantly shorter in the quick population (8.4 +/- 4.7 vs. 11.2 +/- 7.4 days, P = 0.004) It is safe and cost-effective to implant an ICD without an EPS, an extensive DFT-, and a pre-discharge test in carefully selected patients after survived SCD or unstable VTs.
    Europace 01/2008; 9(12):1144-50. · 3.05 Impact Factor
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    ABSTRACT: Implantation of an additional HV-P/S lead versus extraction of the defective HV-P/S lead and implantation of a new one is one possible therapeutic approach in cases of a defective high-voltage pace/sense lead (HV-P/S). No information is available on potential differences in clinical outcome in these different approaches. Between January 2000 and February 2006, 86 patients with HV-P/S lead defect received either an additional transvenous HV-P/S lead (n = 33, group 1) or the HV-P/S lead was replaced (n = 53, group 2). The duration of the initially implanted leads was significantly different in the two groups (7.4 +/- 2.9; group 1 and 4.1 +/- 3.4 years; group 2). The outcome of these two groups of patients was retrospectively analyzed. Seventy-three patients [85%] survived until the end of follow-up of 29 +/- 15 (group 1) and 33 +/- 21 (group 2) months (P = ns), respectively. Thirteen patients died: six in group 1 and seven in group 2 (P = ns). Fourteen patients experienced perioperative complications (group 1: six; group 2: eight; P = ns). ICD system-related complications occurred in 22 patients (group 1: seven; group two: 15; P = ns). The event-free cumulative survival of patients with additional and replaced HV-P/S lead for postoperative events (including death) after 1, 2, and 3 years was 82%, 70%, 70%, and 86%, 81%, 66%, respectively (P = 0.93). Implantation of an additional HV-P/S lead or replacement of the HV-P/S lead in case of HV-P/S lead failure is statistically not different concerning mortality and morbidity. There are no predictors for further lead defects. Implantation of an additional HV-P/S lead should not be recommended in young patients or patients with greater likelihood of living many years. Predictors for death were an age over 70 years and renal insufficiency.
    Journal of Cardiovascular Electrophysiology 12/2007; 18(11):1172-7. · 3.48 Impact Factor
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    ABSTRACT: To assess procedural characteristics and adjudicated procedure-related (<or=30 days) major adverse events among patients who underwent cardiac resynchronization therapy (CRT) implantation in the CARE-HF study. The CARE-HF study shows that CRT improves symptoms and reduces morbidity and mortality in New York Heart Association (NYHA) class III/IV chronic heart failure (CHF) patients. However, safe and proper implantation of pacing systems remains key to effective CRT delivery. Generalized linear modeling was used to examine the relationships between first implant success/failure and: NYHA class; beta-adrenergic blocker use; underlying ischemic vs. non-ischemic heart disease; history of coronary artery bypass graft or valve surgery; left ventricular (LV) end-diastolic volume<or=vs. >300 cm(3); and, influence of the participating study-centres. Implantation was attempted in 404/409 patients assigned to CRT, and in 65/404 patients assigned to medical therapy. Among these 469 patients, 450 (95.9%) received a successfully implanted and activated device. Complications occurred within 24 h in 47 patients (10.0%), mainly lead dislodgments (n = 10, 2.1%) and coronary sinus dissection/perforation (n = 10, 2.1%), and between 24 h and 30 days in 26 patients (5.5%), mainly lead dislodgment (n = 13, 2.8%). Mean LV lead stimulation threshold was significantly higher than at the right atrium or right ventricle, though remained stable, delivering effective, and reliable CRT. Implanting experience was the only predictor of procedural outcome. Transvenous CRT system implantation, using a CS lead designed for long-term LV pacing, was safe and reliable. As implanting centres become more experienced, this success rate is expected to increase further.
    Europace 08/2007; 9(7):516-22. · 3.05 Impact Factor
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    ABSTRACT: The purpose of this prospective, randomized, multicentre study was to investigate whether the incidence of ventricular tachyarrhythmia can be reduced in standard implantable cardioverter/defibrillator (ICD) patients by implanting a dual-chamber ICD capable of atrial therapy delivery. A Jewel AF or GEM III AT ICD (Medtronic Inc., Minneapolis, MN, USA) was implanted in 122 patients (62.3 +/- 10.5 years; 84.4% male; coronary artery disease 71.3%; left ventricular ejection fraction 39.7 +/- 13.6%; secondary ICD indication 91%). Overall, 31.2% of the patients had paroxysmal atrial fibrillation (AF)/atrial tachycardia (AT) before ICD implantation (n = 38). Implantable cardioverter/defibrillator therapies for AT/AF were activated and de-activated every 3 months in a cross-over study design. The mean follow-up was 18.5 +/- 7.7 months (6.29 +/- 2.2 cross-over/patient). Overall, there were 684 episodes of ventricular tachyarrhythmias in 48.4% of patients (n = 59). In 33.6% of patients (n = 41), 532 supraventricular tachyarrhythmias occurred. Activation of ICD therapies for AT/AF did not result in a reduction of ventricular tachyarrhythmias (P = 0.92). Patients with monomorphic ventricular tachycardias (mVTs) as index arrhythmia for ICD implantation or inducible mVTs in the electrophysiological study had the highest probability of recurrences of ventricular tachyarrhythmias. For patients with standard indications for ICD therapy and no indication for cardiac pacing, a dual-chamber ICD capable of atrial tachyarrhythmia treatment offers no benefit concerning a reduction of ventricular tachyarrhythmias.
    Europace 08/2007; 9(7):534-9. · 3.05 Impact Factor
  • Dirk Böcker, Horst Wedekind
    Kardiologie up2date 06/2007; 3(2):123-137.
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    ABSTRACT: Primary Programming of Stability and Onset Criteria. Introduction: Inappropriate therapies are the most frequent adverse event in patients with implantable cardioverter defibrillators (ICDs). Most ICDs offer a stability criterion to discriminate ventricular tachycardia (VT) from atrial fibrillation and an onset criterion to discriminate VT from sinus tachycardia. The efficacy and safety of these criteria, if used immediately after implantation, is unknown.Methods and Results: In a case control study, 87 patients in whom stability and onset criteria had been activated immediately after ICD implantation were matched to 87 patients in whom these criteria had not been activated. The groups were matched for known predictors of inappropriate therapies. With stability and onset criteria off, 24 patients (28%) received inappropriate therapies due to atrial fibrillation (n = 14) or sinus tachycardia (n = 11); with stability and onset on, only 11 patients (13%) were treated by the ICD due to atrial fibrillation (n = 5) or sinus tachycardia (n = 7) (log rank: P = 0.029). Five patients suffered inappropriate therapies despite the fact that onset (n = 4) or stability (n = 1) criteria were not fulfilled once tachycardias continued for a prespecified duration. Only one patient experienced a failure to detect VT due to the onset criterion; none because of stability.Conclusion: The immediate use of stability and onset criteria after ICD implantation reduces inappropriate therapies due to atrial fibrillation and sinus tachycardia. Because of the potential for underdetection of VT, this approach should be limited to tachycardia rates hemodynamically tolerated by the patient.
    Journal of Cardiovascular Electrophysiology 04/2007; 10(2):145 - 153. · 3.48 Impact Factor
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    ABSTRACT: Die vorliegenden Leitlinien zur Implan- tation von Defibrillatoren wurden in Überarbeitung der Leitlinien der Deut- schen Gesellschaft für Kardiologie, Herz und Kreislaufforschung, wie sie 1993 publiziert worden sind, erstellt, ba- sierend auf einer sorgfältigen Analyse der wissenschaftlichen Daten zur aktu- ellen Therapie ventrikulärer Tachy- arrhythmien. Auch in Zukunft sollen diese Leitlinien in regelmäßigen Ab- ständen revidiert werden, wenn der wissenschaftliche Erkenntnisstand dies erforderlich macht.
    Clinical Research in Cardiology 01/2007; 95(12):696-708. · 4.17 Impact Factor
  • Journal of Cardiac Failure 12/2006; 12(9):762-762. · 3.07 Impact Factor
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    ABSTRACT: Sudden death among implantable cardioverter defibrillator (ICD) recipients is well known. The underlying mechanism remains unclear in most cases. One possible mechanism is an accidentally induced arrhythmia by the ICD itself. This report describes for the first time a case of a life-threatening ventricular arrhythmia induced by a specific algorithm for ventricular arrhythmia reconfirmation before shock delivery in a fourth-generation ICD.
    Journal of Cardiovascular Electrophysiology 10/2006; 17(9):1026-8. · 3.48 Impact Factor

Publication Stats

3k Citations
611.68 Total Impact Points


  • 1991–2011
    • University of Münster
      • • Department of Cardiology
      • • Department of Cardiology and Angiology
      Münster, North Rhine-Westphalia, Germany
  • 2009
    • St. Marien-Hospital Hamm
      Hamm, Rheinland-Pfalz, Germany
  • 2000–2007
    • Universitätsklinikum Münster
      • Department für Kardiologie und Angiologie
      Muenster, North Rhine-Westphalia, Germany
    • Klinikum St. Georg Leipzig
      Leipzig, Saxony, Germany
  • 2005
    • University of Hamburg
      Hamburg, Hamburg, Germany
  • 2003
    • University of Bologna
      • Institute of Cardiology
      Bologna, Emilia-Romagna, Italy
    • EUREGIO-KLINIK Albert-Schweitzer-Straße GmbH
      Nordhorn, Lower Saxony, Germany
  • 1994
    • Arteriosclerosis Prevention Institute
      München, Bavaria, Germany