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Biomedical subjects

Berndt Lüderitz

Publications and source records attributed to Berndt Lüderitz.

At least 37 records · Page 2Linked to original sources
PubMed2005

Cells of primarily extra-valvular origin in degenerative aortic valves and bioprostheses.

AIMS: We assessed aortic valves from patients with non-rheumatic aortic valve stenosis (AS) and with degenerative aortic valve bioprostheses (BP) for the presence of progenitor cell and leukocyte subtype-specific markers. METHODS AND RESULTS: Diseased valve probes from a total of 87 patients (60 AS and 27 BP) were studied. We assessed presence and localization of endothelial progenitor cells (EPCs: CD34, CD133), dendritic cells (DCs: S100), T-lymphocytes (CD3), and macrophages (CD68) by immunohistochemical and morphometric analyses. In the majority of valves, we detected cell-bound signals of CD34 (48% of AS, 74% of BP, respectively), CD133 (58%/81%), S100 (58%/93%), CD3 (62%/81%), and CD68 (78%/93%). Labelled cells were predominantly localized within the valvular fibrosa. As key results, frequency of EPCs, DCs, macrophages, and lymphocytes was found significantly higher in BP when compared with AS (CD34: 19.2+/-23.2 vs. 5.7+/-13.0%; CD133: 13.7+/-12.4 vs. 5.5+/-8.3%; S100: 15.2+/-12.2 vs. 5.7+/-8.9%; CD3: 3.3+/-2.7 vs. 1.1+/-1.4%; CD68: 35.3+/-26.6 vs. 3.4+/-4.1%; each P<or=0.001). CONCLUSION: EPCs and DCs were detected in a large collective of degenerative aortic valves, more frequently in bioprostheses than in native cusps. Aortoluminal presence of these primarily extra-valvular cells co-localized with inflammatory cells is a novel key feature involved in aortic valve degeneration.

Aged↗
PubMed2005

Patients with atrial fibrillation and dense spontaneous echo contrast at high risk a prospective and serial follow-up over 12 months with transesophageal echocardiography and cerebral magnetic resonance imaging.

OBJECTIVES: We sought to assess the prognosis of patients with atrial fibrillation (AF) and dense spontaneous echo contrast (SEC) and to determine the incidence of cerebral embolism under continued oral anticoagulation. BACKGROUND: Patients with AF and dense SEC have an increased risk of cerebral embolism. However, there is little knowledge about the long-term fate and the rate of clinical silent cerebral embolism under continued oral anticoagulation. METHODS: Between 1998 and 2001, all consecutive patients with AF and dense SEC were included in the study. We performed serial and prospective transesophageal echocardiography, cranial magnetic resonance imaging, and clinical examinations during a period of 12 months. RESULTS: A total of 128 patients with dense SEC and AF were included. The control group consisted of 143 patients with faint SEC and AF. During the follow-up period, three patients (2%) had cerebral embolism with neurologic deficits. A total of eight patients (6%) died due to embolic events, and 19 (15%) patients had silent embolism, as documented on cerebral magnetic resonance imaging. Patients with an event had significantly lower left atrial appendage peak emptying velocities and more commonly had a history of previous thromboembolism and denser SEC, as compared with patients without an event. CONCLUSIONS: Patients with AF and dense SEC have a high likelihood of cerebral embolism (22%) and/or death, despite oral anticoagulation. Low peak emptying velocities of the left atrial appendage and dense SEC are independent predictors of an event.

Anticoagulants↗
PubMed2005

Mean platelet volume as marker of restenosis after percutaneous transluminal coronary angioplasty in patients with stable and unstable angina pectoris.

INTRODUCTION: Several experimental and clinical studies have demonstrated that platelet size and function correlate since large platelets are hemostatically more reactive than platelets of normal size. Since platelets play a crucial role in vascular remodeling after percutaneous transluminal coronary angioplasty (PTCA), we investigated the influence of the mean platelet volume (MPV), a parameter of platelet size, on restenosis after PTCA. METHODS: The retrospective study comprised 174 patients who underwent elective PTCA and follow-up angiography within 6 months thereafter. According to the follow-up angiograms, the patients were assigned to group A ("restenosis", n=74) or group B ("no restenosis", n=100). Both groups were compared in regard to pre-procedural hematological routine parameters including MPV, platelet count, hematocrit, white blood cell count and fibrinogen. RESULTS: MPV was significantly increased in group A, compared with that in group B (8.75+/-0.99 fl vs. 8.04+/-0.74 fl, p<0.001). This difference in MPV was evident in patients with stable and unstable angina pectoris. In addition, MPV had an impact on the time-related incidence of angiographic restenosis, as early restenosis was associated with higher pre-procedural MPV values. Platelet count correlated inversely with MPV (r=-0.36, p<0.01) and was significantly lower in group A than in group B. The remaining hematological parameters were not different in both groups. CONCLUSIONS: The MPV seems to be a marker of coronary restenosis in patients undergoing PTCA. Patients with high pre-procedural MPV values might benefit from an intensified antiplatelet therapy after coronary interventions.

Angina Pectoris↗
PubMed2005

[Long-term outcome of intrapleural fibrinolytic therapy via small-bore catheter drainage in the management of complicated parapneumonic effusion and empyema-a case series].

BACKGROUND AND PURPOSE: Complicated parapneumonic effusions (PPE) and pleural empyemas (PE) are associated with increased morbidity and mortality. Intrapleural fibrinolytic therapy (IFT) has been established, besides video-assisted thoracoscopy (VATS), in the management of PPE and PE. Combination of IFT and small-bore catheter drainage has previously not been investigated. PATIENTS AND METHODS: 15 patients consecutively referred for PPE and PE were managed with simultaneous IFT via small-bore catheter drainage (9, 12, 14 F). In addition to evaluation of primary outcome, lung function testing and radiologic studies were obtained after 3 months to predict potential pulmonary restrictive impairment and residual pleural thickening. RESULTS: Primary outcome of all 15 patients was positive. Only one patient showed a significant residual pleural thickening. None of the patients showed a restrictive lung function pattern. CONCLUSION: Proven applicability of IFT via small-bore catheter drainage seems to be effective in the face of long-term outcome. Further prospective and multicentric studies should be initiated to investigate the practicability of IFT via small-bore catheter drainage.

Adult↗
PubMed2005

[Cardiac pacing for the prevention of atrial fibrillation. A current review].

Several prospective randomized clinical trials have reported that atrial-based "physiological" pacing is associated with a lower incidence of paroxysmal and permanent atrial fibrillation than single-chamber ventricular pacing in patients with conventional pacemaker indication. Whether atrial pacing itself is antiarrhythmic remains still uncertain. By contrast, right ventricular pacing is considered to beget atrial fibrillation, even in preserved AV synchrony during dual-chamber pacing. A number of clinical trials investigated the impact of sitespecific atrial pacing and advanced atrial pacing algorithms on the secondary prevention of atrial fibrillation. Multisite pacing (dual-site right atrial or biatrial pacing) was demonstrated to add only minimal benefit for the prevention of atrial fibrillation. By contrast, in some studies septal pacing and specific atrial pacing algorithms were reported to reduce the recurrence of atrial fibrillation in selected patients. At present, however, it remains unclear how to identify these patients. In clinical practice, the effectiveness of specific atrial pacing algorithms and/or septal pacing has to be tested out in the individual case. These therapeutic options should be considered in patients with a conventional indication for antibradycardia pacing and, additionally, symptomatic atrial fibrillation.

Algorithms↗
PubMed2005

Post mortem analysis of a left atrial appendage occlusion device (PLAATO) in a patient with permanent atrial fibrillation.

Thromboemoblism is the most feared complication of atrial fibrillation. Percutaneous left atrial appendage occlusion is a new interventional procedure for reducing thromboembolic risk in patients with atrial fibrillation. The paper reports of a post mortem analysis of the device demonstrating that one year after implantation the atrial surface of the device is completely covered by neo-endothelium and the device occludes the appendage completely.

Aged↗
PubMed2005

Incidence of cerebral embolism after cardioversion of atrial fibrillation: a prospective study with transesophageal echocardiography and cerebral magnetic resonance imaging.

BACKGROUND: After cardioversion of atrial fibrillation the risk for cerebral embolism is increased. There is little knowledge about the incidence of cerebral embolism for patients with transesophageal echocardiography (TEE)-guided cardioversion under oral anticoagulation. METHODS: Consecutive patients with atrial fibrillation and TEE-guided cardioversion were included in the study. We performed serial TEE studies, Holter electrocardiography, cranial magnetic resonance imaging, and clinical examinations during a period of 4 weeks before and after cardioversion. Oral anticoagulation was continued or initiated in all patients. RESULTS: During the observation period 6 of 127 (4.7%) patients had new embolic lesions after cardioversion documented on cerebral magnetic resonance imaging. Patients with an event were significantly older (P = .04) and had a larger left atrium (P = .04) than patients without event. CONCLUSION: Patients with atrial fibrillation and oral anticoagulation have a low rate of clinical apparent cerebral embolism after TEE and anticoagulation-guided cardioversion. The rate of silent cerebral embolism is almost 5%. Age and left atrial size are predictors for an event.

Administration, Oral↗
PubMed2005

Patients at high risk with atrial fibrillation: a prospective and serial follow-up during 12 months with transesophageal echocardiography and cerebral magnetic resonance imaging.

OBJECTIVE: Patients with atrial fibrillation and echocardiographic risk factors have a relevant risk of cerebral embolism. However, there is little knowledge about the long-term fate and the rate of clinical silent cerebral embolism under continued oral anticoagulation. Our aims were to assess the prognosis of patients with atrial fibrillation and determine a high-risk group with an increased risk of cerebral embolism under oral anticoagulation. METHODS: A total of 173 consecutive patients with persistent or permanent atrial fibrillation and left atrial (LA) thrombi, dense spontaneous echocontrast, reduced LA appendage peak emptying velocities, or a combination of these were included in the study. In all, 169 patients with atrial fibrillation and without echocardiographic risk factors served as control patients. We performed serial and prospective transesophageal echocardiography, cranial magnetic resonance imaging, and clinical examinations during a period of 12 months. RESULTS: During the follow-up period 7 (4%) of the patients at high risk had cerebral embolism with neurologic deficits. A total of 4 (2%) patients died because of embolic events and 19 (11%) patients had silent embolism as documented on magnetic resonance imaging. In the control group, 10 (6%) patients had embolic events documented on magnetic resonance imaging; one was clinically apparent. Study patients with an event had more often previous thromboembolism (P < .0001). CONCLUSIONS: Patients with persistent or permanent atrial fibrillation and LA thrombi, dense spontaneous echocontrast, or reduced LA appendage peak emptying velocities have an explicitly increased risk of cerebral embolism (17%) despite oral anticoagulation. Previous thromboembolic event is another important predictor for an event.

Administration, Oral↗
PubMed2005

Changes of pulmonary vein orifice size and location throughout the cardiac cycle: dynamic analysis using magnetic resonance cine imaging.

INTRODUCTION: Anatomically guided left atrial ablation is used increasingly for treatment of atrial fibrillation (AF). Three-dimensional mapping systems used for pulmonary veins (PV) encircling ablation procedures anticipate a stable size and position of the PV orifice. The aim of the current study was therefore to analyze changes of PV orifice size and location throughout the cardiac cycle using cine magnetic resonance imaging (MRI). METHODS AND RESULTS: Twenty-five healthy volunteers were studied using a 1.5 Tesla MRI system. MR angiograms were acquired with a breath-hold three-dimensional fast-spoiled gradient-echo imaging (3D FSPGR) sequence in the coronal plane before and after gadolinium injection. Maximum intensity projections and multiplanar reformations were performed to reconstruct images of the PV. Bright blood cine imaging in the axial view was acquired by a steady-state free precession pulse sequence. Twenty bright blood images were obtained per cardiac cycle. The axial (anterior-posterior) PV orifice diameter was measured in all 20 images. For analysis of PV movement the location of the orifice posterior edge was plotted on scale paper. PV orifice size depends on the stage of the cardiac cycle with the largest diameter in late atrial diastole and a mean decrease of 32.5% during atrial systole. Location changes of the PV orifice are in the range of up to 7.2 mm and larger in the coronal (lateral-medial) than in the sagittal (anterior-posterior) direction. CONCLUSION: PV orifice size and location is not as stable as anticipated by three-dimensional mapping systems used for PV encircling left atrial ablation procedures. RF application close to the presumed orifice location should therefore be avoided to minimize the risk of PV stenosis.

Adult↗
PubMed2005

Impact of age and basic heart rate on heart rate turbulence in healthy persons.

Postextrasystolic acceleration of heart rate (HR), known as HR turbulence (HRT) is attenuated in patients with coronary artery disease at increased risk of adverse events. The influence of age and basic HR on HRT have not been evaluated in a large cohort of persons. In 95 healthy individuals, HRT onset (TO) and slope (TS) were calculated from 24-hour ambulatory electrocardiograms, as well as the turbulence timing (TT). Gender specific differences in TO and TS were compared in simple, linear, weighted regression model. The influence of age and the basic HR preceding ventricular premature contractions on HRT were examined. We found that, in men and women, TO decreases as basic HR increases (P < 0.01). In contrast, in men, TS decreased as basic HR increases, whereas in women, basic HR influenced TS only slightly (P < 0.01). A multiple, linear regression model revealed a decrease in HRT with increasing age in men. In conclusion, physiological acceleration of the HR within the first 11 beats after premature ventricular complex (VPC) was observed in >75% of healthy individuals. An accelerating HR preceding the VPC influenced HRT in men. An increasing age was associated with a decrease in HRT in men and a decrease in TO in women. These results illustrate the importance of physiological modulations of HRT when used for risk stratification, especially in older populations.

Adult↗
PubMed2005

Gold-tip electrodes--a new "deep lesion" technology for catheter ablation? In vitro comparison of a gold alloy versus platinum-iridium tip electrode ablation catheter.

Gold-tip electrodes. Radiofrequency (RF) catheter ablation is widely used to induce focal myocardial necrosis using the effect of resistive heating through high-frequency current delivery. It is current standard to limit the target tissue-electrode interface temperature to a maximum of 60-70 degrees C to avoid char formation. Gold (Au) exhibits a thermal conductivity of nearly four times greater than platinum (Pt-Ir) (3.17 W/cm Kelvin vs 0.716 W/cm Kelvin), it was therefore hypothesized that RF ablation using a gold electrode would create broader and deeper lesions as a result of a better heat conduction from the tissue-electrode interface and additional cooling of the gold electrode by "heat loss" to the intracardiac blood. Both mechanisms would allow applying more RF power to the tissue before the electrode-tissue interface temperature limit is reached. To test this hypothesis, we performed in vitro isolated liver and pig heart investigations comparing lesion depths of a new Au-alloy-tip electrode to standard Pt-Ir electrode material. Mean lesion depth in liver tissue for Pt-Ir was 4.33+/-0.45 mm (n=60) whereas Au electrode was able to achieve significantly deeper lesions (5.86+/-0.37 mm [n=60; P<0.001]). The mean power delivered using Pt-Ir was 6.95+/-2.41 W whereas Au tip electrode delivered 9.64+/-3.78 W indicating a statistically significant difference (P<0.05). In vitro pig heart tissue Au ablation (n=20) increased significantly the lesion depth (Au: 4.85+/-1.01 mm, Pt-Ir: 2.96+/-0.81 mm, n=20; P<0.001). Au tip electrode again applied significantly more power (P<0.001). Gold-tip electrode catheters were able to induce deeper lesions using RF ablation in vitro as compared to Pt-Ir tip electrode material. In liver and in pig heart tissue, the increase in lesion depth was associated with a significant increase in the average power applied with the gold electrode at the same level of electrode-tissue temperature as compared to platinum material.

Animals↗
PubMed2005

Clinical prediction of cavotricuspid isthmus dependence in patients referred for catheter ablation of "typical" atrial flutter.

INTRODUCTION: Typical atrial flutter (AFL) can be cured by catheter ablation of the cavotricuspid isthmus (CTI). The surface electrocardiogram (ECG) is not always diagnostic of isthmus dependence of AFL. The aim of this study was to evaluate clinical parameters for the prediction of isthmus-dependent AFL. METHODS AND RESULTS: Sixty consecutive adult patients without suspected atriotomy-related AFL, congenital heart disease, or previous AFL ablation, referred for catheter ablation of presumed typical AFL were studied. All patients had distinct flutter waves in the inferior leads, suggestive of CTI-dependent AFL, either on presentation to the electrophysiology (EP) lab or documented on prior ECG. Electrophysiology study was performed in the standard fashion. Patients who presented to the EP laboratory not in AFL underwent arrhythmia induction with a burst pacing protocol. A clinical history of persistent AFL (P = 0.0001) and existence of AFL on presentation to the EP laboratory (P = 0.0001) were strong predictors of CTI dependence. History of atrial fibrillation (P = 0.19), structural heart disease (P = 0.6), hypertension (P = 0.4), and previous cardiac surgery (P = 0.5), as well as the nature of AFL-related symptoms (P = 0.5), were not predictors of CTI-dependent AFL documented during EP study. CONCLUSION: In patients with ECG suggestive of typical AFL, the presence of persistent rather than paroxysmal AFL and presentation to the EP laboratory in AFL are strong predictors of CTI-dependent AFL. A paroxysmal pattern of AFL predicts noninducibility of CTI-dependent AFL during EP study. CTI ablation may therefore be less effective in these patients.

Atrial Flutter↗
PubMed2005

Left internal mammary angiography complicated by subclavian tortuosity: a technical note.

Current elective bypass procedures frequently involve placement of a left internal mammary artery (LIMA). Accordingly, there is an increased need to prove either preoperative adequacy or postoperative patency of this graft. We report a patient with a tortuous left subclavian artery inaccessible for any standard catheterization technique for LIMA opacification. The problem was overcome by a CHOICE PT guidewire whose trackability permitted the passage through the subclavian kinking and, subsequently, to coaxially advance a multipurpose catheter to the entrance of the LIMA. The described setting may be helpful for diagnostic LIMA imaging in selected cases.

Cardiac Catheterization↗