Publications by authors named "Dieter Zenker"

28 Publications

  • Page 1 of 1

Epicardial implantation of a leadless pacemaker in a lamb model.

Pacing Clin Electrophysiol 2020 12 22;43(12):1481-1485. Epub 2020 Sep 22.

Department of Pediatric Cardiology and Intensive Care Medicine, Georg August University Medical Center, Göttingen, Germany.

Background: Pacemaker used in small children typically consist of an abdominally placed generator and epicardially affixed leads, making such a system prone to lead dysfunction during growth. Aim of this study was to investigate the feasibility of epicardial pacing with a leadless pacemaker in a lamb model.

Animals And Methods: Seventeen lambs underwent epicardial implantation of a Micra transcatheter pacing system (TPS) (Medtronic, Minneapolis, MN, USA) via left-lateral thoracotomy to the left ventricle (LV) surface (n = 11/17) and to the left atrial appendage (n = 6). Ventricular devices were fixated with the tines within the pericardium, whereas the tines of the atrial devices penetrated the myocardium of the left atrial appendage. After 31 weeks, animals were sacrificed and hearts were explanted for histological analysis.

Results: Following implantation, median P/R amplitude was 4.25/5.5 mV while median pacing threshold was 1.1/1.9 V at 0.24 ms. After 31 weeks, median P/R amplitude was 3.3/4.2 mV. Median atrial pacing threshold was 0.5/0.24 ms. Eight of 10 ventricular pacemakers had lost capture at standard impulse width even at maximum impulse amplitude. On explantation, firm adhesion of the device to the thoracic wall and dislodgement of the electrode tip was found in those ventricular devices.

Conclusions: Firm fixation of the Micra electrode to the epicardial surface as applied to the atrial devices resulted in excellent electrical properties during midterm follow up. Pericardial fixation as in the ventricular devices was associated with loss of capture. Therefore, it is important to embed the tines in the myocardium and to choose an alternative implantation site allowing for safe fixation of the Micra TPS in a position perpendicular to ventricular epimyocardium.
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http://dx.doi.org/10.1111/pace.14067DOI Listing
December 2020

Viabahn stent graft compared with prosthetic surgical above-knee bypass in treatment of superficial femoral artery disease: Long-term results of a retrospective analysis.

Medicine (Baltimore) 2018 Oct;97(40):e12449

Department of Thoracic and Cardiovascular Surgery, University Medical Center, Georg-August University, Göttingen.

The prosthetic surgical above-knee bypass (pAKB) is a standard therapy in superficial femoral artery (SFA) occlusive disease in absence of suitable vein. Viabahn graft has been established as a promising alternative. Since limited comparative data are available, we conducted a retrospective study to compare long-term outcomes of these 2 therapies in a real-world setting.Records of 52 patients (60 limbs), who were treated by pAKB (29 limbs) or Viabahn (31 limbs) were reviewed. Patients were followed up by clinical assessment, physical examination, and resting ankle brachial index (ABI) after 3, 6, 12 months and yearly thereafter. Long-term data were available for 97% in the Viabahn and 93% for pAKB after 73 ± 3.7 months (mean ± standard error [SE]).Long-term primary and secondary patencies in Viabahn group were 40% and 70%, respectively, after 63 ± 2.8 months (mean ± SE). Total lesion length was 19 ± 11.06 cm (mean ± SE), graft size was 6 ± 0.72 mm (mean ± SE). Hospital stay was 4.8 ± 0.72 days (mean ± SE). Limb salvage was achieved in 90%. Patients in the pAKB group showed a total lesion length of 24.39 ± 1.97 cm (mean ± SE), graft size was 7 ± 0.99 mm (mean ± SE). Long-term analysis after 83 ± 6.8 months (mean ± SE) revealed a primary patency of 78% with a secondary patency of 94%. Hospital stay was 10.4 ± 1.27 days (mean ± SE). Limb salvage was ensured in 97%. Long-term primary patency was lower for Viabahn (P = .044), secondary patency (P = .245), and leg salvage (P = .389) were not significantly different. However, hospital stay was shorter (P = .0002) for Viabahn.Long-term analysis of Viabahn revealed a significantly lower primary patency, a similar secondary patency, limb salvage, and significantly shorter hospital stay when compared with pAKB. Our data suggest that pAKB is still a valuable option in patients suitable for an open operation. However, Viabahn can be used as a less invasive treatment in high risk patients.
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http://dx.doi.org/10.1097/MD.0000000000012449DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6200476PMC
October 2018

Risk and Outcome after Simultaneous Carotid Surgery and Cardiac Surgery: Single Centre Experience.

Int J Vasc Med 2018 16;2018:7205903. Epub 2018 Aug 16.

Department for Thoracic, Cardiac, and Vascular Surgery, University of Göttingen, Göttingen, Germany.

Objective: Carotid artery stenosis in patients undergoing open-heart surgery may increase risk and deteriorate outcome. The aim of the study was the analysis of risks and outcome after simultaneous carotid and cardiac surgery.

Methods: We retrospectively reviewed the medical records of 100 consecutive patients who underwent simultaneous carotid surgery and open-heart surgery during a 5-year period (from 2006 to 2010). Seventy patients were male and 30 female; the mean age was 70.9±7.9 years (median: 71.8 years). Seventy-three patients underwent coronary bypass grafting (CABG), 18 patients combined CABG and valve procedures, 7 patients CABG combined with other procedures, and 3 patients isolated valve surgery. More than half of patients had had bilateral carotid artery pathology (n=51) including contralateral carotid artery occlusion in 12 cases.

Results: Carotid artery patch plasty was performed in 71 patients and eversion technique in 29. In 75 cases an intraluminal shunt was used. Thirty-day mortality rate was 7% due to cardiac complications (n=5), metabolic disturbance (n=1), and diffuse cerebral embolism (n=1). There were no carotid surgery-related deaths. Postoperatively, transient cerebral ischemia occurred in one patient and stroke with mild permanent neurological deficit (Rankin level 2) in another patient.

Conclusion: Simultaneous carotid artery surgery and open-heart surgery have low risk. The underlying cardiac disease influences outcome.
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http://dx.doi.org/10.1155/2018/7205903DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6116460PMC
August 2018

Safety profile of baroreflex activation therapy (NEO) in patients with resistant hypertension.

J Hypertens 2018 08;36(8):1762-1769

Department of Nephrology and Rheumatology.

Objective: Unlike safety data of baroreflex activation therapy device (Rheos), only few data of the currently used second device (Barostim neo) are available and little is reported about common side effects.

Methods: We prospectively analyzed patients with resistant hypertension treated with Barostim neo. A standardized interview regarding side effects of the therapy was performed in routine follow-up visits after device implantation in 42 patients to determine adverse events staged into three degrees.

Results: Within 6 months of baroreflex activation therapy, the office mean arterial blood pressure decreased from 169 ± 27 to 148 ± 29 mmHg systolic (P < 0.001), respectively, to 145 ± 24 mmHg after 1 year (P < 0.001), whereas the number of prescribed antihypertensive classes decreased from 6.6 ± 1.5 to 5.6 ± 1.8 (P < 0.001). Adverse events were combination of the following field depending on the severity (I° mild: local discomfort, clinical observation only, no intervention indicated; II° moderate: medically significant such as occurrence of hypertensive crisis, syncope, arrhythmias; III° severe: life-threatening events or urgent medical intervention indicated). Adverse events I° were present in almost all patients (97.6%), and occurred mainly within first 6 months after device activation. Device-related events were most frequently and could be resolved by optimization of device parameters. Most procedure-related adverse events were directly related to the incision or anesthetic procedure. Adverse events II° occurred in 28.6% patients treated with Barostim neo, whereas patients' elevated individual risks might be potential triggers. Because of individual diversity of blood pressure response and the occurrence of adverse events, no standardization of parameters of implantable pulse generator could be found. By adapting the pulse generator settings individually, most of adverse events I° resolved without sequel.

Conclusion: Though there are common side effects, Barostim neo significantly lowers blood pressure in resistant hypertension and provides an adequate safety profile. Regular patient visits are necessary to register side effects.
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http://dx.doi.org/10.1097/HJH.0000000000001753DOI Listing
August 2018

Supra-aortic interventions for endovascular exclusion of the entire aortic arch.

J Vasc Surg 2017 07;66(1):281-297.e2

Department of Thoracic, Cardiac and Vascular Surgery, University of Göttingen, Göttingen, Germany.

Objective: Our aim was to analyze the outcomes of endovascular exclusion of the entire aortic arch (proximal landing in zone 0, distal landing in zone III or beyond, after Ishimaru) in which complete surgical debranching of the supra-aortic vessels (I), endovascular supra-aortic revascularization (chimney, fenestrated, or branched grafts) with partial surgical debranching (II), or total endovascular supra-aortic revascularization (III) was additionally performed.

Methods: Publications describing endovascular repair of the aortic arch (2000-2016) were systematically searched and reviewed.

Results: From a total of 53 relevant studies including 1853 patients, only 1021 patients undergoing 35 different total aortic arch procedures were found eligible for further evaluation and included in group I, II, or III (429, 190, and 402 patients, respectively). Overall early mortality was higher in group I vs groups II and III (P = .001; 1 - β = 95.6%) but exceeded in group III (18.6%) and group II (14.0%) vs group I (8.0%; P = .044; 1 - β = 57.4%) for diseases involving zone 0. Mortality was higher in all subgroups treated for zone 0 disease compared with corresponding subgroups treated for zone I to zone III disease. The incidence of cerebral ischemic events was increased in groups I and II vs group III (7.5% and 11% vs 1.7%; P = .0001) and correlated with early mortality (R = .20; P = .033). The incidence of type II endoleaks and endovascular reintervention was similar between groups and correlated with each other (R = .37; P = .004). Type Ia endoleak occurred more often in groups II and III than in group I (7.1% and 12.1% vs 5.8%; P = .023) and correlated with midterm mortality (R = .53; P = .005). Retrograde type A dissection was low in all groups, whereas aneurysm growth was higher in group III (2.6%, 4.2%, 10.7%; P = .002), correlating with midterm mortality (R = .311; P = .009). Surgical revision slightly correlated with surgical complications (R = .18; P = .044) but not with mortality (R = .10; P = .214).

Conclusions: Because early mortality was significantly higher in patients receiving endovascular treatment for proximal aortic disease, endovascular-based approaches proved to be feasible alternatives to hybrid surgical procedures, especially when they were performed for aneurysms located in the distal aortic arch. Whereas cerebral ischemia accompanies both surgical and endovascular involvement of the supra-aortic vessels, endoleaks and aneurysm growth remain hallmarks of endovascular supra-aortic repair. Because surgical revision had no impact on mortality, complete surgical debranching may become the option of choice for patients with good life expectancy suffering from proximal aortic arch disease, whereas total endovascular procedures could be particularly advantageous in patients with short life expectancy and distal aortic arch disease.
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http://dx.doi.org/10.1016/j.jvs.2017.04.024DOI Listing
July 2017

Baroreflex activation therapy in patients with prior renal denervation.

J Hypertens 2016 08;34(8):1630-8

aDepartment of Nephrology and Rheumatology, Georg-August-University, Göttingen bDepartment of Internal Medicine III, University of Cologne, Germany cDepartment of Nephrology, University of Dresden, Germany dSt. Josefs Hospital, Cloppenburg, Germany eDepartment of Thoracic Cardiovascular Surgery fDepartment of Cardiology and Pneumology, Georg-August-University, Göttingen, Germany.

Background: Both baroreflex activation therapy (BAT) and renal denervation modulate sympathetic activity. The aim of this study was to systematically investigate whether additive modulation of autonomic nervous system by BAT lowers blood pressure (BP) in patients who still suffer from uncontrolled resistant hypertension despite prior renal denervation.

Methods: From 2012 to January 2015, patients treated with BAT for uncontrolled resistant hypertension, who prior received renal denervation were consecutively analyzed in four German centers for hypertension. Analyses of office BP, 24-h ambulatory BP, central hemodynamics, parameters of renal function were performed.

Results: A total of 28 patients, who underwent renal denervation at least 5 months before and still suffer from uncontrolled BP, were subsequently treated with BAT. The office SBP decreased from 182 ± 28 to 163 ± 27 mmHg (P < 0.01) with a responder rate of 68% (office SBP reduction ≥10 mmHg) at month 6, whereas the number of prescribed antihypertensive drug classes remained unchanged (6.2 ± 1.5 vs. 6.0 ± 1.7, P = 0.30). Serum creatinine, estimated glomerular filtration rate and cystatin C remained stable (P = 1.00, P = 0.41 and P = 0.22, respectively), whereas albuminuria was significantly reduced by a median of -29% (P = 0.02). Central SBP (-15 ± 24 mmHg, P = 0.047) and end systolic pressure (-14 ± 20 mmHg, P = 0.03) were significantly reduced.

Conclusion: The present data demonstrate that BAT may exert BP-lowering as well as antiproteinuric effects in patients with prior renal denervation. However, precise evaluation of BAT effects in patients with prior renal denervation will need randomized controlled trials using sham procedures.
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http://dx.doi.org/10.1097/HJH.0000000000000949DOI Listing
August 2016

Pulmonary artery endoleak compression after thoracic endovascular aortic repair.

Asian Cardiovasc Thorac Ann 2015 Sep 12;23(7):879. Epub 2014 Mar 12.

Department of Thoracic and Cardiovascular Surgery, University of Göttingen, Germany.

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http://dx.doi.org/10.1177/0218492314528924DOI Listing
September 2015

Is there an alternative to the surgical above-knee bypass in treatment of superficial femoral artery disease? Experiences with Viabahn stent graft.

Vasc Endovascular Surg 2013 Oct 17;47(7):502-6. Epub 2013 Jul 17.

1Department of Thoracic and Cardiovascular Surgery, University of Göttingen, Göttingen, Germany.

Objective: We conducted a retrospective study to compare short- and mid-term patencies of Viabahn with surgical above-knee prosthetic bypass (pAKB).

Methods: The records of 52 patients with either pAKB (n = 25) or Viabahn (n = 27) were reviewed. The majority had Rutherford clinical grade 3. Patients were followed after 3, 6, and 12 months and yearly thereafter.

Results: For Viabahn, the short-term (1-16 months) primary patency rate was 60% with a secondary patency rate of 90%, and mid-term (1-68 months) patencies of 47% and 83.3%, respectively. In pAKB, the short-term results revealed a primary patency rate of 78% with a secondary patency of 91% and mid-term results of 65% and 90%, respectively. No statistical difference was found concerning short-term patencies. Mid-term primary patency was lower for Viabahn (P < .05) and secondary patency proved no significant difference.

Conclusion: Viabahn revealed similar short-term primary and secondary patencies but lower mid-term primary patency. It provides a good alternative therapy to pAKB.
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http://dx.doi.org/10.1177/1538574413495964DOI Listing
October 2013

Passive-fixation lead failure rates and long-term patient mortality in subjects implanted with Sprint Fidelis electrodes.

Europace 2014 Feb 28;16(2):258-64. Epub 2013 Jun 28.

Division of Clinical Electrophysiology, Department of Cardiology and Pneumology, University Medical Center Göttingen, Georg-August-University, Robert-Koch-Str. 40, 37075 Göttingen, Germany.

Aims: To evaluate passive-fixation lead failure rates and long-term patient survival in subjects implanted with Sprint Fidelis electrodes.

Methods And Results: We identified 748 subjects who received a Sprint Fidelis (n = 429; Medtronic models 6948: 94.8%, 6949: 2.6%, 6930: 1.9%, 6931: 0.7%) or a Sprint 'non-Fidelis' implantable cardioverter defibrillator lead (n = 319, Medtronic models 6944: 68.6%, 6947: 17.9%, 6942: 7.8%, 6943: 3.4%, 6945: 2.2%) at our centre between 1998 and 2008. Kaplan-Meier patient survival was lower in the Fidelis group than in the Control cohort (68.4 vs. 77.0% at 5 years, P = 0.0061), but multivariate analyses revealed no significant association between mortality and implanted lead type. Passive-fixation lead failure rate at 5 years was 14.4% (95% confidence interval (CI) [9.2, 19.3]) in the Fidelis (n = 414) group and 1.8% (95% CI [0.0-3.8]) in the Control (n = 241) cohort (P < 0.001 upon multivariate comparison).

Conclusion: Failure rates of passive-fixation Sprint Fidelis leads are increased and similar to those previously reported for active-fixation Fidelis electrodes. Despite the elevated risk for lead failure and its potential sequelae, the Sprint Fidelis has no obvious impact on long-term mortality.
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http://dx.doi.org/10.1093/europace/eut185DOI Listing
February 2014

Randomized Clinical evaluatiON of wireless fluid monitoriNg and rEmote ICD managemenT using OptiVol alert-based predefined management to reduce cardiac decompensation and health care utilization: the CONNECT-OptiVol study.

Contemp Clin Trials 2013 Jan 13;34(1):109-16. Epub 2012 Oct 13.

Dept. of Cardiology and Pneumology, Heart Research Center, University Medical Center, Göttingen, Germany.

Aims: The CONNECT-OptiVol study is designed to investigate whether wireless fluid monitoring using OptiVol alerts as well as implantable cardioverter-defibrillator (ICD) remote monitoring (RM) reduces cardiac decompensations and health care utilization in ICD patients, as compared to standard clinical care.

Methods: Patients undergoing implantation of wireless telemetry-enabled dual chamber (ICD-DR) or cardiac resynchronization therapy/defibrillator (CRT-D) devices with the OptiVol feature are eligible for the study. In a randomized fashion, OptiVol function, its audible alert as well as its remote alert, and other ICD RM alerts are switched ON or OFF. The primary study objective is to estimate an improvement of heart failure status. The primary endpoint is measured as a prolongation of the time to first hospitalization due to worsened heart failure. The secondary objectives are to estimate: a reduction of the time from event to clinical decision, a reduction of the rate of health care utilization, and improved quality of life (QoL) measures (secondary endpoints). The study is designed as a single center pilot study with 180 patients randomized 1:1 to the two study arms.

Conclusion: The CONNECT-OptiVol study aims to answer whether wireless fluid monitoring integrated into RM may reduce cardiac decompensations and health care utilization in ICD patients. The results can be used to adequately power future studies evaluating the benefit of these features. Study enrollment has been completed, and follow-up is expected to be finished in September 2012.
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http://dx.doi.org/10.1016/j.cct.2012.10.001DOI Listing
January 2013

Intimal sarcoma of the inferior vena cava with extension to the right atrium.

Asian Cardiovasc Thorac Ann 2012 Feb;20(1):87-8

Department of Thoracic and Cardiovascular Surgery, University of Göttingen, Germany.

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http://dx.doi.org/10.1177/0218492311419472DOI Listing
February 2012

Treatment of cardiovascular implantable electronic device infection with daptomycin.

Pacing Clin Electrophysiol 2012 Apr 11;35(4):e105-7. Epub 2011 Jul 11.

Department of Thoracic and Cardiovascular Surgery, University of Göttingen, Göttingen, Germany.

We describe a case of 83-year-old man who was admitted to our department for treatment of recurrent device-pocket infections. Our report shows that in a case of high-risk patient with a complicated cardiac implantable electric devices infection involving multidrug-resistent gram-positive pathogen, the application of daptomycin in combination with staged surgical therapy can be efficient and safe.
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http://dx.doi.org/10.1111/j.1540-8159.2011.03163.xDOI Listing
April 2012

Acute and long-term feasibility of contralateral transvenous lead placement with subcutaneous, pre-sternal tunnelling in patients with chronically implanted rhythm devices.

Europace 2011 Jul 31;13(7):1004-8. Epub 2011 Mar 31.

Department of Cardiology and Pulmology, Heart Center, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany.

Aims: A growing number of patients with implanted rhythm devices require new or additional leads, e.g. in cases of electrode defect or planned device upgrade. If the ipsilateral subclavian vein is occluded, transvenous electrode placement from the contralateral side with subcutaneous, pre-sternal lead tunnelling (TUN) is one potential option that has been described in anecdotal reports. The aim of this retrospective study was to determine the acute and long-term feasibility of this approach.

Methods And Results: We identified 18 subjects (67% male, 66±14 years) who underwent TUN at our institution between the years 1995 and 2009. Implantation protocols and patient files were reviewed for peri-operative complications and long-term lead performance. Furthermore, patients were interviewed for symptoms related to the tunnelled lead. Twenty transvenous leads (seven implantable cardioverter defibrillator leads; five left ventricular, four right ventricular, four right atrial pace/sense electrodes) were successfully tunnelled without significant peri-operative complications. The follow-up duration was 29±36 (3-162) months. Electrical parameters remained stable in 95% (19/20) of the tunnelled leads. In one right ventricle pace/sense lead, ventricular oversensing was documented 10 months after TUN, and the lead was replaced because a structural defect could not be excluded. Five patients died without causal relationship to the procedure 4-48 months after TUN. One patient reported discomfort related to the tunnelled lead.

Conclusion: Contralateral transvenous lead implantation with subcutaneous, pre-sternal TUN appears to be a feasible option in selected patients with an implanted rhythm device and ipsilateral subclavian vein occlusion.
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http://dx.doi.org/10.1093/europace/eur072DOI Listing
July 2011

Feasibility of implantable cardioverter defibrillator treatment in five patients with familial Friedreich's ataxia--a case series.

Artif Organs 2010 Nov;34(11):1061-5

Department of Thoracic Cardiovascular Surgery, University of Göttingen, Germany.

Friedreich's ataxia (FRA) is an autosomal recessive disease of the central nervous system that is associated with familial cardiomyopathy. Cardiac involvement is seen in more than 90% of the patients and is the most common cause of death in these patients. We present a case series and discuss the indications for implantable cardioverter defibrillator (ICD) implantation in FRA with review of the literature. Five pediatric patients who suffer from FRA (four female and one male, mean age 17.4 years) underwent ICD implantation between 2007 and 2008 in the University Hospital of Goettingen. The diagnosis of FRA was established by standard clinical criteria and proven in each case by genotyping at the frataxin locus. The time from diagnosis to ICD implantation was 10.4±1.73 years (range 8-15 years). All patients received transvenous lead systems. There were no intraoperative and postoperative complications. At the latest follow-up, the neuromuscular symptoms exhibited no further progress and no ICD activations were noticed. Only minor repolarization changes were seen on electrocardiogram. All patients had normal echocardiographic findings and no angina has been reported. Coronary angiographies were normal. It is evident that many FRA patients develop ventricular dysfunction. In the absence of a definitive surgical cure an ICD is generally indicated in young patients with hemodynamically significant sustained ventricular tachyarrhythmias for prevention of sudden cardiac death. Our experience implies the safe use of ICD in children with FRA.
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http://dx.doi.org/10.1111/j.1525-1594.2010.01140.xDOI Listing
November 2010

Indications for reoperation late after correction of tetralogy of Fallot.

Cardiol Young 2010 Aug 11;20(4):396-401. Epub 2010 May 11.

Department for Thoracic, Cardiac, and Vascular Surgery, University of Göttingen, Göttingen, Germany.

Objective: Correction of tetralogy of Fallot has excellent long-term results. The present retrospective study investigates the indications for reoperation late after corrective surgery.

Methods: Data from 914 consecutive cases who underwent correction of tetralogy of Fallot in our department between 1960 and 2002 were retrospectively reviewed and analysed. In 91 patients, a total of 102 reoperations were performed late after repair.

Results: The mean time interval between corrective surgery and the first reoperation was 12.8 years. The main indication for reoperation was residual ventricular septal defect in nearly half of the cases, mostly isolated, but also in combination with a right ventricular outflow tract aneurysm or pulmonary stenosis. One-fourth of reoperated patients underwent a procedure on their pulmonary artery or pulmonary valve: replacement of pulmonary valve, replacement of primary implanted pulmonary artery conduits with or without concomitant surgery, and surgery for isolated peripheral pulmonary stenosis. The remaining indications were right ventricular outflow tract aneurysms and others. Aneurysms of the right ventricular outflow tract were seen mostly after the use of autologous - untreated - pericardial patch in 18 of 21 cases.

Conclusion: The number of reoperations for residual ventricular septal defect decreased during the study period. The primary use of conduits led to an increased number of reoperations for conduit exchange due to degeneration or failure. Use of an untreated autologous pericardial patch for enlargement of the right ventricular outflow tract should be avoided due to increased risk for aneurysm formation.
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http://dx.doi.org/10.1017/S1047951110000442DOI Listing
August 2010

Myocardial ischemia with left ventricular outflow obstruction.

J Cardiothorac Surg 2009 Sep 17;4:51. Epub 2009 Sep 17.

Department of Thoracic and Cardiovascular Surgery, University of Göttingen, Germany.

We report an unusual case of a 32-year old man who was treated for a hypertrophic obstructive cardiomyopathy (HOCM) with a DDD pacing with short AV delay reduction in the past. Without prior notice the patient developed ventricular fibrillation and an invasive cardiac diagnostic was performed, which revealed a myocardial bridging around of the left anterior descending artery (LAD). We suspected ischemia that could be either related to LAD artery compression or perfusion abnormalities due to AV delay reduction with related to diastolic dysfunction.
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http://dx.doi.org/10.1186/1749-8090-4-51DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2753314PMC
September 2009

Cardiac resynchronization therapy and atrial overdrive pacing for the treatment of central sleep apnoea.

Eur J Heart Fail 2009 Mar 12;11(3):273-80. Epub 2009 Jan 12.

Kardiologie und Pneumologie, Georg-August-Universität, Göttingen, Germany.

Aims: The combined therapeutic impact of atrial overdrive pacing (AOP) and cardiac resynchronization therapy (CRT) on central sleep apnoea (CSA) in chronic heart failure (CHF) so far has not been investigated. We aimed to evaluate the effect of CRT alone and CRT + AOP on CSA in CHF patients and to compare the influence of CRT on CHF between CSA positive and CSA negative patients.

Methods And Results: Thirty patients with CRT indication underwent full night polysomnography, echocardiography, exercise testing, and neurohumoral evaluation before and 3 months after CRT implantation. In CSA positive patients (60%), two additional sleep studies were conducted after 3 months of CRT, with CRT alone or CRT + AOP, in random order. Cardiac resynchronization therapy resulted in significant improvements of NYHA class, left ventricular ejection fraction, N-terminal pro-brain natriuretic peptide, VO(2)max, and quality of life irrespective of the presence of CSA. Cardiac resynchronization therapy also reduced the central apnoea-hypopnoea index (AHI) (33.6 +/- 14.3 vs. 23.8 +/- 16.9 h(-1); P < 0.01) and central apnoea index (17.3 +/- 14.1 vs. 10.9 +/- 13.9 h(-1); P < 0.01) without altering sleep stages. Cardiac resynchronization therapy with atrial overdrive pacing resulted in a small but significant additional decrease of the central AHI (23.8 +/- 16.9 vs. 21.5 +/- 16.9 h(-1); P < 0.01).

Conclusion: In this study, CRT significantly improved CSA without altering sleep stages. Cardiac resynchronization therapy with atrial overdrive pacing resulted in a significant but minor additional improvement of CSA. Positive effects of CRT were irrespective of the presence of CSA.
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http://dx.doi.org/10.1093/eurjhf/hfn042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2645047PMC
March 2009

Intrathoracic impedance monitoring to detect chronic heart failure deterioration: relationship to changes in NT-proBNP.

Eur J Heart Fail 2007 Jun-Jul;9(6-7):716-22. Epub 2007 Apr 25.

Herzzentrum Göttingen, Abteilung Kardiologie und Pneumologie, Georg-August-Universität Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany.

Background: An alert algorithm, based on intrathoracic impedance monitoring, has been incorporated into a cardiac resynchronisation device (CRT) to detect pulmonary fluid accumulation, and to audibly alert patients to decompensating chronic heart failure (CHF).

Aims: To evaluate this algorithm, alert events were correlated with changes in NT-proBNP concentration and CHF status.

Methods And Results: In a prospective observational study of 62 patients (89% male, aged 67+/-1 year), NT-proBNP plasma concentrations, clinical CHF status, and device data were collected at enrolment, during regular follow-up and at device alerts. Over a mean follow-up of 27+/-2 weeks, pooled data indicated a weak, but significant inverse relationship between relative changes in intrathoracic impedance and NT-proBNP (r=-0.3; p<0.001). In 52 device alerts from 35 patients, NT-proBNP increased by 66+/-19% from 2039+/-331 pg/ml (p<0.001). The increase in NT-proBNP was higher in alerts with clinical signs of CHF deterioration (n=30, 89+/-25%; p<0.001) than in alert events without clinical signs (n=22, 25+/-15%; p=n.s.).

Conclusion: Intrathoracic impedance based alert events are associated with a significant increase in NT-proBNP concentration. These data indicate that intrathoracic impedance monitoring might facilitate the outpatient management of CHF patients with implanted CRT devices.
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http://dx.doi.org/10.1016/j.ejheart.2007.03.005DOI Listing
August 2007

Detection of heart failure decompensation using intrathoracic impedance monitoring by a triple-chamber implantable defibrillator.

Heart Rhythm 2005 Sep;2(9):997-9

Department of Cardiology and Pneumology, Georg-August-University, Göttingen, Germany.

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http://dx.doi.org/10.1016/j.hrthm.2005.06.005DOI Listing
September 2005

Congenital coronary artery fistulas in adults: surgical treatment and outcome.

Int J Cardiol 2005 Jan;98(1):57-9

Department of Thoracic, Cardiac and Vascular Surgery, University Hospital, University of Göttingen, Robert-Koch-Str. 40, D-37075 Göttingen, Germany.

Background: Congenital coronary artery fistulas, a subgroup of anomalies of the coronary arteries, are an extremely rare cardiac defect. Most patients are asymptomatic, and if symptoms are presented, they depend on the underlying anatomy. Knowledge of those fistulas is important for prognosis and management.

Methods: Thirteen adult patients with congenital coronary fistulas (8 male, 5 female) were operated in our department during the last decade (1990-1999). Mean age was 61.5+/-10.8 years. Diagnosis was made by coronary angiography, and 15 congenital coronary artery fistulas were found.

Results: All patients were symptomatic with clinical symptoms depending on the associated cardiac disorder. Coronary artery fistulas originated from the proximal left descending artery (n=10), left main stem (n=3), circumflex artery (n=1), right coronary artery (n=1), and drained into the main pulmonary artery (n=14) and left ventricle (n=1). Nine fistulas (60%) were interrupted on the outside of the heart, and six fistulas (40%) were closed through the opened pulmonary artery. There was no surgical death and no fistula-related complication.

Conclusions: Surgical closure of congenital coronary artery fistulas in adults can be performed with a very low risk, and closure is recommended to prevent complications.
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http://dx.doi.org/10.1016/j.ijcard.2002.05.001DOI Listing
January 2005

Intrapulmonary cystic benign teratoma: a case report and review of the literature.

Ann Thorac Cardiovasc Surg 2004 Oct;10(5):290-2

Department of Thoracic and Cardiovascular Surgery, Georg-August-University, Göttingen, Germany.

We describe a 41-year-old woman with a short history of retrosternal chest pain and non-productive cough due to a benign intrapulmonary teratoma originating from the left upper lobe. The clinical, CT features of this rare tumor are presented and the relevant literature is discussed.
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October 2004

Worldwide evaluation of a defibrillation lead with a small geometric electrode surface for high-impedance pacing.

Am Heart J 2003 Dec;146(6):1066-70

Herzzentrum, Georg-August-Universität, Göettingen, Germany.

Background: Pacing leads with a small electrode surface for high-impedance stimulation have been shown to prolong pacemaker longevity, but no sufficient data is available on the safety and feasibility of a defibrillation lead with this novel design.

Methods: We evaluated the clinical performance of a tined, steroid-eluting defibrillation lead with a small electrode surface area (model 6944) in a prospective multicenter study. A total of 542 patients with conventional indications for an implantable cardioverter defibrillator were randomized 1:1 to receive either the model 6944 or a tined, steroid-eluting defibrillation lead with a conventional sized electrode surface area (model 6942). Device performance and electrical parameters were evaluated at implant and 1, 3, 6, and 12 months thereafter (mean follow-up 11.3 +/- 5.6 months).

Results: Baseline characteristics, lead implant success rates, and defibrillation thresholds did not differ significantly between the 2 groups. While pacing thresholds did not differ significantly during follow-up, pacing impedance was approximately twice as high in the model 6944 as in the model 6942 lead (P <.0001). Mean R-wave amplitudes were smaller in patients with a 6944 (9.1 +/- 3.1 mV vs 9.8 +/- 3.6 mV for model 6942, P <.05), but remained stable within both groups throughout the observation period. The total number of ventricular lead-related adverse events and patient survival did not differ significantly between the 2 groups.

Conclusions: The use of a defibrillation lead with a small electrode surface for high-efficiency pacing is safe and feasible and increases pacing impedance without significantly compromising clinical performance.
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http://dx.doi.org/10.1016/S0002-8703(03)00411-3DOI Listing
December 2003

Spontaneous rupture of the left pulmonary artery-caused by long-term steroid use?

Eur J Cardiothorac Surg 2003 Dec;24(6):1037-9

Department of Thoracic and Cardiovascular Surgery, Georg-August-University, Robert-Koch-Str. 40, 37075 Göttingen, Göttingen, Germany.

We describe a 71-year-old woman with spontaneous rupture of the left pulmonary artery. She was admitted with pulselessness of her left arm and lack of sensibility in her left arm and leg. Echocardiography and thoracic CT did not confirm aortic dissection. CT only showed hematoma around the descending aorta. She underwent left-sided thoracotomy. Intraoperatively, a rupture of the left pulmonary artery without any evidence of an aneurysm was found. Potentially predisposing factors for this rupture were long-term use of steroids due to COPD and her age.
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http://dx.doi.org/10.1016/s1010-7940(03)00576-1DOI Listing
December 2003

Subthreshold test pulses versus low energy shock delivery to estimate high energy lead impedance in implanted cardioverter defibrillator patients.

Pacing Clin Electrophysiol 2003 Jan;26(1P2):457-60

Departments of Cardiology and Pneumology, Georg-August-Universität, Göttingen, Germany.

The high energy lead impedance is valuable for detecting lead failure in ICDs, but until recently shock delivery was necessary for high energy impedance measurement. This study compared the use of subthreshold test pulses and low energy test shocks to estimate the high energy impedance. Immediately after implantation of Ventak Prizm ICDs in 29 patients, the lead impedance was measured with five subthreshold (0.4 microJ) test pulses, 5 low energy (1.1 J) shocks, and two to three high energy (16 +/- 4.5 J) shocks. The mean impedances measured using high energy shocks, low energy shocks, and subthreshold pulses were 42.0 +/- 7.3 omega, 46.5 +/- 8.1 omega, and 42.4 +/- 7.1 omega, respectively. The impedances measured using high and low energy shocks differed significantly (P < 0.0001), while those obtained by high energy shocks and low energy pulses did not (P = 0.63). According to the Pearson correlation coefficient, the impedance measurements with subthreshold pulses and low energy shocks were both closely correlated (P < 0.0001) with impedance values determined with high energy shocks. However, while the impedance values tended to be higher when measured with low energy shocks, the concordance correlation coefficient (c) was higher for subthreshold test pulse versus high energy shock (c = 0.92) than for low versus high energy shock (c = 0.73). Furthermore, the intraindividual variability of impedance measurements was lower with subthreshold pulse measurements than with low energy shocks. Compared with low energy shocks, impedance measurement with subthreshold pulses has higher reproducibility and a higher correlation with the impedance obtained by high energy shock delivery. Safe and painless high energy impedance estimation with subthreshold pulses might, therefore, help to detect ICD lead failure during routine follow-up.
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http://dx.doi.org/10.1046/j.1460-9592.2003.00071.xDOI Listing
January 2003

1-year performance of a defibrillation lead with a small electrode surface for high impedance pacing: a randomized, controlled study.

Pacing Clin Electrophysiol 2002 Nov;25(11):1577-82

Department of Cardiology and Pneumology, Georg-August-University, Göttingen, Germany.

A small electrode surface reduces pacing current drain and can extend generator longevity. The study evaluated the performance of a tined, quadripolar defibrillation lead (model 6944) that has a small-surfaced, steroid-eluting electrode tip for high impedance pacing. In a prospective, controlled study, 34 patients with conventional ICD indications were randomized one to one to receive the high impedance model 6944 or a tined defibrillation lead with a conventional sized, steroid-eluting electrode tip model 6942. Lead performance was evaluated at implant, prior to hospital discharge, and 1, 3, 6, and 12 months thereafter. Baseline characteristics did not differ significantly between patients implanted with lead model 6942 (n = 16) or model 6944 (n = 17). One patient randomized to receive the model 6942 was excluded from the study and was implanted with an active-fixation lead after stable lead positioning was neither possible with the 6942 nor with the 6944 electrode. No other lead related adverse events were observed. At implant, there were no significant differences between pacing thresholds, sensing performance, defibrillation impedances, and defibrillation thresholds in both groups, but pacing impedance of the model 6944 (988.6 +/- 217.7 omega) was approximately twice as high as high as in the model 6942 (431.7 +/- 83.7 omega; P < 0.0001). This difference remained highly significant throughout the observation period of 12 months, while R wave amplitudes and pacing thresholds remained equal in both lead models. The use of a tined defibrillation lead with a small, steroid-eluting electrode tip appears safe and results in a high pacing impedance without compromising system performance.
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http://dx.doi.org/10.1046/j.1460-9592.2002.01577.xDOI Listing
November 2002

Pulmonary Langerhans' cell histiocytosis (histiocytosis X) following metastasizing malignant melanoma.

Swiss Med Wkly 2002 Jun;132(21-22):285-7

Klinik für Thorax, Universität Göttingen, Germany.

Background: Pulmonary Langerhans' cell histiocytosis (histiocytosis X) is an uncommon, diffuse interstitial lung disease of unknown cause, mostly presenting in young smokers. Association of pulmonary Langerhans' cell histiocytosis with a malignant neoplasm is rare.

Case Description And Results: We present and discuss the case of a 48-year-old man (ex-smoker) with metastasising malignant melanoma. A few months after chemotherapy and a modified Whipple procedure for retroduodenal metastasis of a malignant melanoma, computer tomographic scans revealed intrapulmonary "ring-shaped structures". Endobronchial biopsies and bronchioalveolar lavage showed no evidence of neoplasm or inflammation. Open-lung biopsy was performed and revealed pulmonary Langerhans' cell histiocytosis.

Conclusion: To our knowledge this is the first reported case of pulmonary Langerhans' cell histiocytosis in association with malignant melanoma. Chemotherapy for malignant melanoma may be related to the development of pulmonary Langerhans' cell histiocytosis.
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http://dx.doi.org/2002/21/smw-09973DOI Listing
June 2002