Stephan Willems

University of Hamburg, Hamburg, Hamburg, Germany

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Publications (296)1164.31 Total impact

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    ABSTRACT: Catheter ablation of complex fractionated atrial electrograms (CFAE), also known as defragmentation ablation, may be considered for the treatment of persistent atrial fibrillation (AF) beyond pulmonary vein isolation (PVI). Concomitant antiarrhythmic drug (AAD) therapy is common, but the relevance of AAD administration and its optimal timing during ablation remain unclear. Therefore, we investigated the use and timing of AADs during defragmentation ablation and their possible implications for AF termination and ablation success in a large cohort of patients. Retrospectively, we included 200 consecutive patients (age: 61 ± 12 years, LA diameter: 47 ± 8 mm) with persistent AF (episode duration 47 ± 72 weeks) who underwent de novo ablation including CFAE ablation. In all patients, PVI was performed prior to CFAE ablation. The use and timing of AADs were registered. The follow-ups consisted of Holter ECGs and clinical visits. Termination of AF was achieved in 132 patients (66 %). Intraprocedural AADs were administered in 168/200 patients (84 %) 45 ± 27 min after completion of PVI. Amiodarone was used in the majority of the patients (160/168). The timing of AAD administration was predicted by the atrial fibrillation cycle length (AFCL). At follow-up, 88 patients (46 %) were free from atrial arrhythmia. Multivariate logistic regression analysis revealed that administration of AAD early after PVI, LA size, duration of AF history, sex and AFCL were predictors of AF termination. The administration of AAD and its timing were not predictive of outcome, and age was the sole independent predictor of AF recurrence. The administration of AAD during ablation was common in this large cohort of persistent AF patients. The choice to administer AAD therapy and the timing of the administration during ablation were influenced by AFCL, and these factors did not significantly influence the moderate single procedure success rate in this retrospective analysis.
    Heart and Vessels 11/2015; DOI:10.1007/s00380-015-0771-0 · 2.07 Impact Factor

  • Europace 10/2015; DOI:10.1093/europace/euv304 · 3.67 Impact Factor
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    PLoS ONE 10/2015; 10(10):e0140386. DOI:10.1371/journal.pone.0140386 · 3.23 Impact Factor

  • Europace 10/2015; DOI:10.1093/europace/euv332 · 3.67 Impact Factor
  • Christian Meyer · Christiane Peiker · Stephan Willems ·

    Kardiologie up2date 09/2015; 11(03):139-142. DOI:10.1055/s-0034-1393072
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    ABSTRACT: Introduction: Permanent pulmonary vein isolation (PVI) remains an essential goal of ablation therapy in patients with atrial fibrillation. Aim of this study was the intraindividual comparison of unexcitability to pacing along the ablation line versus dormant conduction (DC) as additional procedural endpoints. Methods: A total of 58 patients with paroxysmal atrial fibrillation (PAF) underwent PVI by circumferential ablation of ipsilateral pulmonary veins (PVs), followed by testing for DC by adenosine administration. Irrespective of the presence of DC, pacing along the ablation line for left atrium capture was performed and additional radio frequency energy applied if necessary. PVs with initial DC were retested after achieving unexcitability. Results: PVI was achieved in 224 of 224 PVs. In 33 of 224 PVs (15%) DC was revealed. At 92 of 112 ablation lines (82%) sites of excitability were found. Three (9%) of the initial 33 PVs with DC showed further DC after achieving unexcitability at repeated testing. Thirty-two of 33 assumed areas of unmasked PV-LA reconduction as revealed by DC-testing showed a corresponding site of excitability on the ablation line. After a follow-up of 11.6 ± 3.4 months 79% of patients were free of arrhythmia. Conclusions: Pacing for unexcitability can safely identify potential sites of DC and even sites that would have not been detected by testing for DC. Unexcitability, therefore, serves as a suitable and safe procedural endpoint not only for patients with contraindications to adenosine administration. Our data suggest that adenosine may be expendable when achieving unexcitability along the ablation line.
    Journal of Cardiovascular Electrophysiology 09/2015; 26(10). DOI:10.1111/jce.12759 · 2.96 Impact Factor
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    ABSTRACT: Different follow-up methods have been used to report success rates after AF ablation. Recent studies have shown that intermittent rhythm monitoring underestimates the actual AF recurrence rate. We therefore report our experience with continuous rhythm monitoring by implantable loop recorder (ILR) in a large patient cohort. Between 09/2008 and 12/2012, 343 cardiac surgical patients underwent concomitant surgical AF ablation. ILR implantation was performed in 206 patients. ILR interrogation was accomplished at 3, 6 and 12 months postoperatively. Successful ablation was defined as AF Burden <0.5 %. Primary outcome of the study was freedom from AF at 12-month follow-up. Mean patient's age was 70.5 ± 7.4 years. No major ablation- or ILR-related complications occurred. In 4 patients (1.9 %) ILR had to be explanted due to ILR-related wound infection (n = 2) or chronic pain (n = 2). Survival rate at 1-year follow-up was 96.6 %. Freedom from AF rate after 1-year follow-up was 68.5 and 63.6 % off antiarrhythmic drugs, respectively. Statistically significant predictors for successful ablation at 1-year follow-up were smaller LA diameter, shorter duration of AF and preoperative paroxysmal AF. Demographic data, indication for surgery, lesion set and used energy source had no impact on freedom from AF after 1 year. Continuous ILR monitoring after concomitant surgical AF ablation was safe and feasible, with registered freedom from AF rate of 68.5 % at 1-year follow-up. Thus continuous rhythm monitoring provides reliable outcome data and helps to guide antiarrhythmic therapy.
    Heart and Vessels 08/2015; DOI:10.1007/s00380-015-0735-4 · 2.07 Impact Factor
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    ABSTRACT: Catheter ablation is increasingly used to manage atrial fibrillation, but arrhythmia recurrences are common. Adenosine might identify pulmonary veins at risk of reconnection by unmasking dormant conduction, and thereby guide additional ablation to improve arrhythmia-free survival. We assessed whether adenosine-guided pulmonary vein isolation could prevent arrhythmia recurrence in patients undergoing radiofrequency catheter ablation for paroxysmal atrial fibrillation. We did this randomised trial at 18 hospitals in Australia, Europe, and North America. We enrolled patients aged older than 18 years who had had at least three symptomatic atrial fibrillation episodes in the past 6 months, and for whom treatment with an antiarrhythmic drug failed. After pulmonary vein isolation, intravenous adenosine was administered. If dormant conduction was present, patients were randomly assigned (1:1) to additional adenosine-guided ablation to abolish dormant conduction or to no further ablation. If no dormant conduction was revealed, randomly selected patients were included in a registry. Patients were masked to treatment allocation and outcomes were assessed by a masked adjudicating committee. Patients were followed up for 1 year. The primary outcome was time to symptomatic atrial tachyarrhythmia after a single procedure in the intention-to-treat population. The trial is registered with, number NCT01058980. Adenosine unmasked dormant pulmonary vein conduction in 284 (53%) of 534 patients. 102 (69·4%) of 147 patients with additional adenosine-guided ablation were free from symptomatic atrial tachyarrhythmia compared with 58 (42·3%) of 137 patients with no further ablation, corresponding to an absolute risk reduction of 27·1% (95% CI 15·9-38·2; p<0·0001) and a hazard ratio of 0·44 (95% CI 0·31-0·64; p<0·0001). Of 115 patients without dormant pulmonary vein conduction, 64 (55·7%) remained free from symptomatic atrial tachyarrhythmia (p=0·0191 vs dormant conduction with no further ablation). Occurrences of serious adverse events were similar in each group. One death (massive stroke) was deemed probably related to ablation in a patient included in the registry. Adenosine testing to identify and target dormant pulmonary vein conduction during catheter ablation of atrial fibrillation is a safe and highly effective strategy to improve arrhythmia-free survival in patients with paroxysmal atrial fibrillation. This approach should be considered for incorporation into routine clinical practice. Canadian Institutes of Health Research, St Jude Medical, Biosense-Webster, and M Lachapelle (Montreal Heart Institute Foundation). Copyright © 2015 Elsevier Ltd. All rights reserved.
    The Lancet 07/2015; 386(9994). DOI:10.1016/S0140-6736(15)60026-5 · 45.22 Impact Factor
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    ABSTRACT: Marfan syndrome (MFS) is associated with a substantial risk for ventricular arrhythmia and sudden cardiac death (SCD). We used heart rate turbulence (HRT) and deceleration capacity (DC), to evaluate the risk stratification for these patients. We enrolled 102 patients [45 male (44.1 %), age 40.5 ± 14.6 years] with MFS. Blood samples were obtained to determine N-terminal pro-brain natriuretic peptide (NT-proBNP) levels. Transthoracic echocardiography studies were conducted to evaluate heart function parameters and a 24-h holter ECG was performed. An analysis of two HRT parameters, turbulence onset (TO) and turbulence slope (TS), and DC was performed. Therefore, optimal cut-off values were calculated. Primary endpoint was the combination of SCD, ventricular arrhythmia and arrhythmogenic syncope. Secondary endpoint was total mortality. During a follow-up of 1145 ± 491 days, 12 (11.7 %) patients reached the primary and 8 (7.8 %) patients the secondary endpoint. Patients reaching the primary were significantly older, had a higher burden of premature ventricular complexes and NT-proBNP levels and lower values of LVEF, DC and HRT TS. Multivariate analysis identified NT-proBNP (HR 1.25, 95 % CI 1.01-1.56, p = .04) and the abnormal HRT (abnormal TS and/or TO (HR 7.04, 95 % CI 1.07-46.27, p = .04) as independent risk predictor of arrhythmogenic events. Patients with Marfan syndrome are at risk for severe ventricular arrhythmias and SCD. Abnormal HRT parameters and NT-proBNP values are independent risk factors for arrhythmogenic events and SCD. The assessment of these tools may help predicting SCD patients with MFS.
    Clinical Research in Cardiology 06/2015; DOI:10.1007/s00392-015-0873-9 · 4.56 Impact Factor
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    ABSTRACT: Dual atrioventricular nodal non-re-entrant tachycardia (DAVNNT), also known as 'double fire', has recently received more attention since it was demonstrated to mimic more common arrhythmias such as atrial premature beats, atrial fibrillation, and ventricular tachycardia. This is important, since mistaken differential diagnoses and the resulting therapeutic decisions have severe consequences for affected patients. DAVNNT is characterized by conduction characteristics of the atrioventricular (AV) node that leads to a double antegrade conduction of one sinoatrial nodal activity via the slow and fast AV nodal pathways. As a result, the most significant hint from an electrocardiogram (ECG) is a P wave followed by two narrow QRS complexes. Although DAVNNT is rather a rare arrhythmia, it now appears to be more common than previously thought. To date, 68 cases including 3 small single-centre observational studies accumulated over the last 5 years have demonstrated the feasibility and safety of radiofrequency catheter ablation for DAVNNT. Catheter ablation treats this arrhythmia effectively by modifying or eliminating slow pathway function. Here, we review the current state of DAVNNT knowledge systematically and address current challenges presented by this 'ECG chameleon from the AV node'. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email:
    Europace 04/2015; DOI:10.1093/europace/euv056 · 3.67 Impact Factor

  • The Journal of Heart and Lung Transplantation 04/2015; 34(4):S206. DOI:10.1016/j.healun.2015.01.565 · 6.65 Impact Factor
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    ABSTRACT: Recently, a new image integration module (IIM, CartoUnivu™ Module) has been introduced to combine and merge fluoroscopy images with 3-dimensional-(3D)-electroanatomical maps (Carto® 3 System) into an accurate 3D view. The aim of the study was to investigate the influence of IIM on the fluoroscopy exposure during pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) in a prospective randomized trial. Between June and November 2014, a total of 60 patients with PAF (73.3% male, 64.0 ± 9.2 years), who underwent PVI with the endpoint of unexcitability of the ablation line, were randomized to either a conventional 3D mapping system (Carto® 3 System) or to an additional IIM on the basis of an assumed reduction of fluoroscopy exposure by the use of IIM. There were no significant differences in baseline characteristics. The median ablation procedure time was identical in both groups (140.7 ± 27.8 vs. 140.8 ± 39.5 minutes; P = 0.851). A significant decrease of mean fluoroscopy time from 11.9 ± 2.1 to 7.4 ± 2.6 minutes (P < 0.0006) and median fluoroscopy dose from 882.9 to 476.5 cGycm(2) (P < 0.001) was achieved. The main reduction of radiation could be realized during creation of the 3D-map. No major complications occurred during the procedures. After a median follow-up of 125.7 ± 45.6 days 80% of the patients were free from any atrial arrhythmias. CartoUnivu™ module easily integrates into the workflow of PVI with the endpoint of unexcitability of the ablation line without prolonging the procedure time. It is associated with a marked reduction in fluoroscopic dose when compared to a conventional 3D mapping system. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Journal of Cardiovascular Electrophysiology 03/2015; 26(7). DOI:10.1111/jce.12673 · 2.96 Impact Factor
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    ABSTRACT: -In the meantime, catheter ablation (CA) is widely used for the treatment of persistent (pers) atrial fibrillation (AF). There is a paucity of data regarding long-term outcomes. This study evaluates (1) 5 year -single and multiple procedure success and (2) prognostic factors for arrhythmia recurrences after CA of persAF using the "stepwise approach" aiming at AF termination. -549 patients (pts) with persAF underwent de novo CA using the "stepwise approach" (2007-2009). 493 pts were included (holter-ecgs≥every 6 mo). Mean FU was 59±16 mo with 2.1±1.1 procedures/pt. Single and multiple procedure success rates were 20.1% and 55.9%, respectively (80% off AAD). AAD free multiple procedure success was 46%. Long-term recurrences (n=171) were paroxysmal AF in 48 pts (28%) and persAF/atrial tachycardia in 123 pts (72%). Multivariable recurrent event analysis revealed the following factors favoring arrhythmia recurrence: failure to terminate AF during index procedure (HR: 1.279; 95%CI [1.093-1.497]; p=0.002), number of procedures (HR: 1.154; 95% CI [1.051-1.267]; p=0.003), female sex (HR: 1.263; 95% CI [1.027-1.553]; p=0.027) and presence of a structural heart disease (HR: 1.236; 95% CI [1.003-1.524]; p=0.047. AF termination, was correlated with a higher rate of consecutive procedures due to AT recurrences (p=0.003, HR 1.71 95% CI [1.20-2.43] CONCLUSIONS: -CA of persAF using the "stepwise approach" provides limited long term freedom of arrhythmias often requiring multiple procedures. AF termination, the number of procedures, gender and the presence of structural heart disease correlate with outcome success. AF termination is associated with consecutive AT procedures.
    Circulation Arrhythmia and Electrophysiology 03/2015; 8(2). DOI:10.1161/CIRCEP.114.001672 · 4.51 Impact Factor
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    ABSTRACT: Background: Catheter ablation (CA) of ventricular tachycardia (VT) is an important treatment option in patients with structural heart disease (SHD) and implantable cardioverter defibrillator (ICD). A subset of patients requires epicardial CA for VT. Objective: The purpose of the study was to assess the significance of epicardial CA in these patients after a systematic sequential endocardial approach. Methods: Between January 2009 and October 2012 CA for VT was analyzed. A sequential CA approach guided by earliest ventricular activation, pacemap, entrainment and stimulus to QRS-interval analysis was used. Acute CA success was assessed by programmed ventricular stimulation. ICD interrogation and 24h-Holter ECG were used to evaluate long-term success. Results: One hundred sixty VT ablation procedures in 126 consecutive patients (114 men; age 65±12years) were performed. Endocardial CA succeeded in 250 (94%) out of 265 treated VT. For 15 (6%) VT an additional epicardial CA was performed and succeeded in 9 of these 15 VT. Long-term FU (25±18.2month) showed freedom of VT in 104 pts (82%) after 1.2±0.5 procedures, 11 (9%) suffered from repeated ICD shocks and 11 (9%) died due to worsening of heart failure. Conclusions: Despite a heterogenic substrate for VT in SHD, endocardial CA alone results in high acute success rates. In this study additional epicardial CA following a sequential endocardial mapping and CA approach was performed in 6% of VT. Thus, due to possible complications epicardial CA should only be considered if endocardial CA fails.
    International Journal of Cardiology 03/2015; 182. DOI:10.1016/j.ijcard.2014.12.003 · 4.04 Impact Factor
  • M Antz · S Willems · B A Hoffmann ·
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    ABSTRACT: In addition to treatment with drugs to control the rate and rhythm, the method of catheter ablation is a cornerstone in the treatment of atrial fibrillation. Another crucial part in treating patients with atrial fibrillation is an adequate oral anticoagulation. Apart from the vitamin K antagonists (VKA) phenprocoumon and warfarin, the direct oral anticoagulants (DOAC) apixaban, dabigatran and rivaroxaban have been approved for oral anticoagulation of patients with atrial fibrillation. As a result there are different potential treatment possibilities for pre-interventional, peri-interventional and post-interventional anticoagulation in the setting of catheter ablation for atrial fibrillation. Due to increasing clinical experience with DOAC and the increasing number of atrial fibrillation ablations worldwide, peri-interventional treatment strategies are continuously changing. Therefore, the current article discusses current standards and gives practical guidance.
    Herz 02/2015; 40(1). DOI:10.1007/s00059-014-4196-9 · 0.69 Impact Factor

  • European Heart Journal 02/2015; 36(5):255-6. DOI:10.1093/eurheartj/ehu476 · 15.20 Impact Factor
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    The Thoracic and Cardiovascular Surgeon 01/2015; 63(S 01). DOI:10.1055/s-0035-1544301 · 0.98 Impact Factor
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    ABSTRACT: Background: Concomitant Surgical AF ablation is an established procedure, recommended in guidelines. However many surgeons are reluctant to perform AF ablation in patients with significantly enlarged left atrium. We therefore analyzed outcomes of patients with left-atrial diameter >55 mm undergoing concomitant AF ablation. Methods: Between 05/2003 and 12/2012 124 patients with significantly enlarged left-atrium >55 mm underwent concomitant surgical AF ablation. Rhythm monitoring was accomplished by implantable loop recorder (ILR) interrogation (n = 54), or 24-h Holter-ECG (n = 70). Successful ablation was defined as AF Burden <0.5 % in ILR interrogation or absence of AF episode >30 s in 24-h Holter-ECG. Primary endpoint of the study was freedom from AF at 12 months follow-up. Results: Mean patient's age was 65.7+/-9.6 years, 69.4 % were male. No major ablation or ILR related complications occurred. Mean LA diameter was 60.7+/-4.4 mm. Survival rate at one-year follow up was 94.4 %. 11 (8.8 %) patients received additional catheter-based ablation, while 23 (18.5 %) had an electrical cardioversion during follow-up period. Overall freedom from AF rate after one-year follow-up was 64.4 % and 59.4 % off antiarrhythmic drugs respectively. Logistic regression analysis identified preoperative paroxysmal AF, duration of AF and LA diameter > 70 mm as predictors for rhythm outcome at 12 months follow-up. Conclusion: In this patient cohort with significantly enlarged LA diameter, concomitant surgical AF ablation provided freedom from AF of 64.4 % after one-year follow-up. However in this patient population, an accurate postoperative care with interventions like medical or- electrical cardioversion and additional catheter based ablation is necessary to achieve satisfactory results.
    The Thoracic and Cardiovascular Surgeon 01/2015; 63(S 01). DOI:10.1055/s-0035-1544273 · 0.98 Impact Factor
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    ABSTRACT: Atrial fibrillation (AF) is the most common cause of ischemic stroke. Recent data suggest that AF patients after successful ablation have the same risk for thromboembolic events (TE) as patients without AF. Despite current guideline recommendations it is still under debate if oral anticoagulation (OAC) can be safely discontinued after ablation. We analyzed follow-up (FU) after ablation of paroxysmal AF (PAF) in a high- (previous stroke; group 1) and a low-risk group (no previous stroke; group 2) based on data from the German Ablation Registry to reveal real-life prescription behavior. Overall 29 centers in Germany participated by performing AF-ablation. Between April 2008 and April 2011, 83 patients in group 1 and 377 patients in group 2 with a first ablation of PAF were included in the registry. Mean CHA2DS2-VASc-Score was 4.2 ± 1.4 (group 1) vs. 1.6 ± 1.2 (group 2) (p < 0.0001). No peri-interventional TE was observed. Arrhythmia recurrence was seen in 47.4 vs. 48.4 % (p = 0.79) during a median FU of 489 (453-782) days, resulting in a repeat procedure in 20.0 vs. 20.7 % (p = 0.88), respectively. OAC was discontinued in 38.6 % in group 1 vs. 66.3 % in group 2 (p < 0.0001) during FU. TE during FU occurred more often in group 1 than in group 2 (4.3 vs. 0.3 %, p < 0.05). Even in patients with previous stroke, OAC was frequently discontinued during FU after PAF ablation in this observational study. However, TE occurred significantly more frequent in these high-risk patients. These data argue against OAC discontinuation after ablation in patients with previous stroke.
    Clinical Research in Cardiology 12/2014; 104(6). DOI:10.1007/s00392-014-0804-1 · 4.56 Impact Factor
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    ABSTRACT: Atrial arrhythmias lower the biventricular pacing percentage in cardiac resynchronization therapy (CRT) treated patients (pts) and have a high prevalence in this population. External electrical cardioversion (ECV) is commonly performed to restore sinus rhythm. There is a paucity of data on the safety and efficacy of ECV in pts with CRT devices. Forty-three pts with CRT devices undergoing ECV at two centers were included prospectively. Devices were interrogated immediately prior to and after ECV, as well as after 4 weeks. Devices (CRT-D in 38 and CRT-P in 5) were all implanted in left pectoral position, with predominantly bipolar left ventricular (LV) leads. Sixty-one shocks were delivered, all biphasic. Arrhythmia had recurred in 36 % of pts at follow-up (FU). There was a significant increase in LV lead threshold voltage and drop in bipolar LV lead impedance after ECV, which returned to normal at FU. An at least twofold increase in pacing threshold voltage at FU was seen in 2 LV leads and a 0.5 V increase in threshold in 3 LV leads. Overall, biventricular pacing significantly increased during FU. ECV in CRT pts was safe and effective in this two-center study. A transient increase in LV lead pacing threshold was observed. Relevant changes in pacing threshold at FU occurred in five LV leads-identification and regular FU of these pts are necessary. Restoring SR through ECV significantly increased the biventricular pacing percentage but arrhythmia recurrence was frequent. CRT pts with atrial arrhythmias require close FU after ECV.
    Clinical Research in Cardiology 12/2014; 104(5). DOI:10.1007/s00392-014-0800-5 · 4.56 Impact Factor

Publication Stats

4k Citations
1,164.31 Total Impact Points


  • 2007-2015
    • University of Hamburg
      • • Department of Cardiology, Electrophysiology
      • • University Heart Center
      Hamburg, Hamburg, Germany
  • 1997-2015
    • University Medical Center Hamburg - Eppendorf
      • • Department of Cardiology, Electrophysiology
      • • Department of Cardiovascular Surgery
      Hamburg, Hamburg, Germany
  • 2011
    • CHU de Québec
      Quebec City, Quebec, Canada
    • Johannes Gutenberg-Universität Mainz
      Mayence, Rheinland-Pfalz, Germany
    • Institut für Interdisziplinäre Medizin Hamburg
      Hamburg, Hamburg, Germany
  • 2010
    • Ludwig-Maximilian-University of Munich
      • Department of Internal Medicine I
      München, Bavaria, Germany
  • 1994-2007
    • University of Münster
      • Department of Cardiology and Angiology
      Muenster, North Rhine-Westphalia, Germany