Search PubMed⌕ Search

Biomedical subjects

Gerhard Steinbeck

Publications and source records attributed to Gerhard Steinbeck.

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

Outcome of ablation for sustained focal atrial tachycardia in patients with and without a history of atrial fibrillation.

OBJECTIVES: The aim of this study was to determine the long-term results of ablation for sustained focal atrial tachycardia in patients with and without a history of atrial fibrillation. METHODS: A history of atrial fibrillation was documented in 25 of 111 patients (23%) with focal atrial tachycardias. We studied the results of focal ablation during a follow-up of 27 +/- 22 months. RESULTS: Enlargement of left atrium (Odds ratio 2.99) and septal origin of the atrial focus (Odds ratio 5.68) were independent predictors of coexisting atrial fibrillation. Patients with a septal origin of the focal atrial tachycardia were older (62 vs. 54 years) and had a higher rate of structural heart disease than patients with a non-septal site of origin (51 vs. 29%). A higher rate of atrial fibrillation was found in patients with anteroseptal (56%), midseptal (50%) and posteroseptal (36%) atrial tachycardias than in patients with focal atrial tachycardias arising from the crista terminalis (9%), the tricuspid (12%) and mitral annulus (0%), the ostia of thoracic veins (17%) and other right atrial (27%) and left atrial free wall sites (10%). During the follow-up, atrial fibrillation was documented in 3% of patients without preexisting atrial fibrillation. In patients with focal atrial tachycardia and a history of atrial fibrillation, at least one episode of atrial fibrillation was documented during follow-up in 64% of patients, but 60% of patients reported marked symptomatic improvement. CONCLUSION: An increased rate of coexisting atrial fibrillation was found in patients with a septal origin of focal atrial tachycardia. Ablation of the focal atrial tachycardia may eliminate both arrhythmias, but patients with a history of atrial fibrillation may still be prone to recurrences of atrial fibrillation after focal ablation.

Atrial Fibrillation↗
PubMed2005

Targeted pharmacological reversal of electrical remodeling after cardioversion--rationale and design of the Flecainide Short-Long (Flec-SL) trial.

Persistent atrial fibrillation (AF) causes relevant mortality and cardiovascular and noncardiovascular morbidity. Therefore, maintenance of sinus rhythm is an important clinical goal, especially when the patient is symptomatic, despite the fact that current treatment strategies are not sufficient to completely prevent recurrent AF. In addition to underlying atrial disease that predisposes to AF, AF in itself induces structural and electrical adaptations ("electrical remodeling" and "structural remodeling"). Underlying disease processes and parts of structural remodeling are not always reversible. Electrical remodeling, in contrast, is reversed by a few weeks of maintenance of sinus rhythm under experimental conditions. This corresponds to the period when most of the recurrent episodes of AF occur after cardioversion. Antiarrhythmic drugs that prolong the atrial action potential can assist in the prevention of recurrent AF by promoting the reversal of electrical remodeling. Such drugs, which are currently used over long periods after cardioversion, may only be needed until the physiological action potential duration is restored, for example, during the first few weeks after cardioversion of persistent AF. This treatment concept that we call "targeted pharmacological reversal of electrical remodeling" would limit both cost and drug-induced side effects of antiarrhythmic drug therapy after cardioversion. The Flec-SL trial, ISECTN62728743, therefore tests the main hypothesis that targeted pharmacological reversal of electrical remodeling by short-term antiarrhythmic drug therapy for 4 weeks after cardioversion is not inferior to standard long-term antiarrhythmic drug therapy for the prevention of recurrent AF after cardioversion in a parallel group, randomized, multicenter, open, blinded end point analysis design. Based on its effectiveness and pharmacokinetic profile, flecainide is used to test the study hypothesis. The trial uses daily transtelephonic electrocardiographic monitoring for all patients and will be conducted within the German Atrial Fibrillation Competence NETwork (AFNET) to facilitate inclusion of patients from electrophysiologically oriented cardiology centers, ordinary hospitals, and office-based physicians.

Anti-Arrhythmia Agents↗
PubMed2005

First clinical experience with the VSTENT: a device for direct left ventricle-to-coronary artery bypass.

BACKGROUND: Stent-based left ventricle-to-coronary artery stent (VSTENT) is a newly developed, alternative surgical revascularization procedure (VCAB). We present here our initial experience using this technique. METHODS: Twelve patients (10 male and 2 female, mean age 61 +/- 13 years) underwent a VCAB concomitant to coronary artery bypass surgery. Myocardial revascularization was performed on-pump with arrested heart in 4 patients, on-pump with beating heart in 6 patients, and off-pump in 2 patients. Average number of coronary anastomoses per patient was 2.4 +/- 0.8. In all cases left internal thoracic artery-to-left anterior descending was used. In each patient only one VSTENT was implanted. Target artery for the VCAB was a diagonal branch in 5 patients, an intermediate branch in one patient and a marginal branch in 6 patients. Mean time for the VCAB was 23 +/- 5 minutes (17 to 30 minutes). RESULTS: An immediate procedural success was observed in 11 of 12 cases. In one case VCAB was not successful and conventional aortocoronary bypass was performed. One patient died on the second postoperative day due to a systemic inflammatory response syndrome. Autopsy demonstrated a patent VSTENT. Angiography was performed in 10 patients 2 to 16 days (9 +/- 5 days) postoperatively showing a patent VSTENT in 8 patients. CONCLUSIONS: The VCAB was feasible and potentially safe in the short-term postoperative follow-up, particularly with increasing experience after the first patients. Though the VSTENT is a promising tool for myocardial revascularization, long-term safety, patency, and performance of the device needs to be determined.

Adult↗
PubMed2005

Different patterns of the fall of impedance as the result of heating during ostial pulmonary vein ablation: implications for power titration.

BACKGROUND: A variety of strategies have been proposed to avoid the risks of pulmonary vein ablation for atrial fibrillation. The fall of impedance during radiofrequency catheter ablation can be used as a real time measure of tissue heating. The aim of this study was to analyze the impedance fall during ostial pulmonary vein ablation and to evaluate whether adjusting power to the fall of impedance may contribute to a reduction of the risk of complications. METHODS: Analysis of biophysical parameters of ablation and determination of ostial diameters during follow-up were performed in 70 patients undergoing impedance-guided segmental ostial pulmonary vein ablation. Repeat radiographic angiography, local electrograms, and baseline impedance were the criteria to define the position of the 4-mm electrode tip at atrial sites or inside the proximal pulmonary veins. RESULTS: Energy application inside the proximal pulmonary veins led to an increased impedance fall inside the first 5-10 mm of the pulmonary veins (1.1 +/- 0.5 Omega/W) as compared to ablation at atrial sites (0.7 +/- 0.3 Omega/W) (P < 0.01). The analysis of temperature and impedance fall during ostial ablation demonstrated an increased impedance fall with heating at sites inside the proximal pulmonary veins (1.5 +/- 0.6 Omega/ degrees C) as compared to atrial sites (1.2 +/- 0.5 Omega/ degrees C) (P < 0.001). The regression lines analyzing these correlations indicated that adjusting power to a maximum impedance fall of 20 Omega would limit heating at pulmonary venous sites to lower temperatures (average maximum temperature: 48 degrees C) than at atrial sites (average maximum temperature: 63 degrees C). The ablation strategy used for segmental ostial ablation in 70 patients, which involved power limitation to a maximum impedance fall of 20 Omega, allowed isolation of 89% of targeted pulmonary veins with a low rate of impedance rises (0.3% of applications). No pulmonary vein stenoses >30% were detected by follow-up computed tomography analysis. CONCLUSIONS: An increased impedance fall as the result of heating during ostial ablation was found inside the proximal pulmonary veins as compared to atrial sites. Adjusting power to the fall of impedance during segmental ostial pulmonary vein ablation contributes to the prevention of overheating inside the pulmonary veins and may lower the risk of coagulum formation and pulmonary vein stenosis.

Atrial Fibrillation↗
PubMed2004

CT measurement of coronary calcium mass: impact on global cardiac risk assessment.

Coronary calcium mass percentiles can be derived from electron beam CT as well as from multidetector-row CT of all manufacturers. Coronary calcium mass may serve as a more individualized substitute for age for cardiac risk stratification. The aim was to investigate the potential impact of CT coronary calcium mass quantification on cardiac risk stratification using an adjusted Framingham score. Standardized coronary calcium mass was determined by multidetector-row CT in a total of 1,473 patients (1,038 male, 435 female). The impact on risk stratification of replacing the traditional Framingham age point score by a point score based on calcium mass relative to age was tested. Any coronary calcium found in males in the age group of 20-34 years and females in the age group of 20-59 years results in an increase of the Framingham score by 9 and 4-7 points, respectively. Only in males 65 years of age and older, none or minimal amounts of coronary calcium decrease the Framingham score by three points. The coronary calcium mass and age-related scoring system may have impact on the reassignment of patients with an intermediate Framingham risk to a lower or higher risk group.

Adult↗
PubMed2004

Relation of coronary calcium scores by electron beam tomography to obstructive disease in 2,115 symptomatic patients.

This angiographically correlated study reports on, for the first time, age- and gender-based distribution of the volumetric calcium score in a large group of patients with suspected coronary artery disease. Volumetric calcium data predicted significant coronary artery disease (>/=50% lumen diameter stenosis) as well as the traditional Agatston score. Exclusion of any calcium was highly accurate in ruling out obstructive disease in symptomatic subjects >/=50 years of age.

Adult↗
PubMed2004

Global gene expression in human myocardium-oligonucleotide microarray analysis of regional diversity and transcriptional regulation in heart failure.

To obtain region- and disease-specific transcription profiles of human myocardial tissue, we explored mRNA expression from all four chambers of eight explanted failing [idiopathic dilated cardiomyopathy (DCM), n=5; ischemic cardiomyopathy (ICM), n=3], and five non-failing hearts using high-density oligonucleotide arrays (Affymetrix U95Av2). We performed pair-wise comparisons of gene expression in the categories (1) atria versus ventricles, (2) disease-regulated genes in atria and (3) disease-regulated genes in ventricles. In the 51 heart samples examined, 549 genes showed divergent distribution between atria and ventricles (272 genes with higher expression in atria, 277 genes with higher expression in ventricles). Two hundred and eighty-eight genes were differentially expressed in failing myocardium compared to non-failing hearts (19 genes regulated in atria and ventricles, 172 regulated in atria only, 97 genes regulated in ventricles only). For disease-regulated genes, down-regulation was 4.5-times more common than up-regulation. Functional classification according to Gene Ontology identified specific biological patterns for differentially expressed genes. Eleven genes were validated by RT-PCR showing a good correlation with the microarray data. Our goal was to determine a gene expression fingerprint of the heart, accounting for region- and disease-specific aspects. Recognizing common gene expression patterns in heart failure will significantly contribute to the understanding of heart failure and may eventually lead to the development of pathway-specific therapies.

Adult↗
PubMed2004

Accuracy of multidetector spiral computed tomography in identifying and differentiating the composition of coronary atherosclerotic plaques: a comparative study with intracoronary ultrasound.

OBJECTIVES: We evaluated the accuracy of contrast-enhanced multidetector spiral computed tomography (MDCT) for the noninvasive detection and classification of coronary plaques and compared it with intracoronary ultrasound (ICUS). BACKGROUND: Noninvasive determination of plaque composition and plaque burden may be important to improve risk stratification and to monitor progression of coronary atherosclerosis. METHODS: We included 46 consecutive patients with a distinctive risk profile, who were investigated by ICUS (Goldvision, 20 MHz, Jomed Inc., Rancho Cordova, California). Due to the inability to slow the heart rate below 65 beats/min (n = 7) and due to renal insufficiency (n = 2), nine of 46 consecutive patients could not be studied by MDCT (Sensation 16, Siemens, Forchheim, Germany). RESULTS: In the remaining 37 patients, 68 vessels were investigated by ICUS, and 58 of these vessels were visualized by MDCT with image quality sufficient for analysis. In these vessels that were divided in 3-mm sections, MDCT correctly classified 62 of 80 (78%) sections containing hypoechoic plaque areas, 87 of 112 (78%) sections containing hyperechoic plaque areas, and 150 of 158 (95%) sections containing calcified plaque tissue. In 484 of 525 (92%) sections, atherosclerotic lesions were correctly excluded. The MDCT-derived density measurements within coronary lesions revealed significantly different values for hypoechoic (49 HU [Hounsfield Units] +/- 22), hyperechoic (91 HU +/- 22), and calcified plaques (391 HU +/- 156, p < 0.02). CONCLUSIONS: This study demonstrates that, in the case of diagnostic image quality, contrast-enhanced MDCT permits an accurate identification of coronary plaques and that computed tomography density values measured within plaques reflect echogenity and plaque composition.

Aged↗
PubMed2004

Retroinfusion-supported stenting in high-risk patients for percutaneous intervention and bypass surgery: results of the prospective randomized myoprotect I study.

The objective of this study was to assess event-free survival and total treatment costs of retroinfusion-supported stenting in high-risk patients compared to bypass surgery. An increasing number of patients with main-stem and main-stem-equivalent stenosis are treated by stent implantation, which appears to be safe in the short-term follow-up. However, there is a lack of randomized studies comparing conventional bypass surgery with stent implantation, particularly in patients with high risk for both treatments. We here report on the 1-year results of a prospective randomized single-center study in patients with symptomatic main-stem and main-stem-equivalent lesions with substantially increased risk for bypass surgery. Patients where randomized to undergo either percutaneous transluminal coronary angioplasty/stent procedure (n = 23) or bypass surgery (n = 21). Patients randomized to stent implantation were supported by selective pressure-regulated retroinfusion of the anterior cardiac vein during ischemia. Patients of the stent group and the bypass group did not differ in baseline characteristics, including Parsonnet score and quality-of-life score. Twenty-eight-day mortality and 1-year mortality rate as well as quality-of-life scores were similar in both groups. Event-free survival after 1 year was higher in the bypass group (71.4% vs. 52.3%; P = 0.02) due to a lower target lesion revascularization rate. With regard to total treatment costs, however, the stent group compared favorably to the bypass group (9,346 +/- 807 vs. 26,874 +/- 3,985 euro), predominantly as a result of a shorter intensive care and hospital stay. In this first randomized study in high-risk patients for stent implantation and bypass surgery, patients with retroinfusion-supported stent implantation had a similar 1-year outcome and quality of life compared to patients with bypass surgery. Though in the stent group event-free survival was lower and target lesion revascularization rate was higher, retroinfusion-supported stent implantation was associated with substantially lower costs and might be considered as an alternative treatment option in this selected group of high-risk patients.

Aged↗
PubMed2004

First human experience with stent-based ventricle-to-coronary artery bypass.

Stent-based ventricle-to-coronary artery bypass (VSTENT) has been shown experimentally to provide systolic instead of physiological diastolic blood flow directly from the left ventricle to a coronary artery distal to a high-grade stenosis. We report on the first successful surgical implantation of a VSTENT in a patient with coronary artery disease. At 3-month follow-up, the VSTENT was patent and showed sufficient regional blood flow at rest with a significant flow reserve. In addition, the patient was asymptomatic during exercise testing. Though encouraging, these observations have to be confirmed and are the subject of an ongoing multicenter study.

Adult↗
PubMed2004

[Diabetes mellitus type 2: coronary calcifications as a predictor of coronary artery disease].

BACKGROUND AND PURPOSE: Patients with diabetes mellitus have an increased risk of developing cardiovascular disease. Therefore, coronary artery disease (CAD) is the most common cause of mortality in these patients. The early and reliable diagnosis of coronary atherosclerosis is crucial for an effective treatment. Determination of coronary calcifications with multislice computed tomography offers the possibility to detect coronary calcifications as a sign of early coronary atherosclerosis. The present study examined the possibility to predict CAD in patients with diabetes mellitus by determination of coronary calcifications. PATIENTS AND METHODS: 632 patients (417 men, 215 women, age 54.6 +/- 17.3 years) with diabetes mellitus and suspected CAD were examined. All patients underwent coronary angiography. Coronary stenoses with lumen narrowing > 50% were regarded as significant CAD. Within 3 days coronary multislice computed tomography (Sensation 4, Siemens Medical Solutions, Forchheim, Germany) was performed and coronary calcifications were quantified using the volume score. Sensitivity, specificity, negative and positive predictive value for prediction of CAD were determined for different cutpoints. RESULTS: 440 patients showed a significant CAD, 315 patients underwent coronary transluminal angioplasty and 57 patients coronary artery bypass surgery. Mean volume score was 421 +/- 461. Volume score increased from 2 +/- 6 for patients < 40 years to 751 +/- 801 for patients > 70 years. Women showed a significantly lower score in all age groups. The mean volume score was significantly higher in patients with CAD compared to those without CAD (587 +/- 642 compared to 40 +/- 53; p < 0.01). In all patients without coronary calcifications, CAD could be ruled out angiographically. Using score 0, 10, 100 as cutoff points for the prediction of CAD, a sensitivity of 100%, 97%, and 87% at a specificity of 25%, 69%, and 82% was calculated. Best results were achieved using the 75th percentile as cutoff point with a sensitivity of 91% and a specificity of 84%. In total, CAD could be diagnosed correctly by quantification of coronary calcifications in 94% of all patients. CONCLUSION: Determination of coronary calcifications by multislice computed tomography could be used in patients with diabetes mellitus to detect coronary atherosclerosis and allows the early and exact diagnosis of CAD.

Calcinosis↗
PubMed2004

Prevalence of resistance against activated protein C resulting from factor V Leiden is significantly increased in myocardial infarction: investigation of 507 patients with myocardial infarction.

BACKGROUND: A point mutation in the gene encoding coagulation factor V is a cause of resistance against activated protein C. The presence of factor V Leiden is linked to 50% of congenital defects causing venous thrombosis. Its relationship to arterial thrombosis, particularly to myocardial infarction, has not been defined. Therefore, we performed a study on the role of factor V Leiden in patients with myocardial infarction. The study was carried out in Bavarians of German origin, a relatively homogeneous population. METHODS AND RESULTS: The study group consisted of 507 patients with documented myocardial infarction (77.5% (393/507) men, 22.5% (114/507) women), with a mean age of 56.1 (range 18-86) years. Strict criteria for patient selection and highly sensitive and specific functional tests for factor V Leiden were used. In addition, all patients with pathological test results were genotyped. The prevalence of factor V Leiden in patients with myocardial infarction was 8.7% (44/507), a significant increase in the prevalence of this mutation compared with the control group (3.7%, P =.0025). The odds ratio was 2.46 (95% CI 1.35-4.50). CONCLUSIONS: A significantly increased prevalence of factor V Leiden in patients with documented myocardial infarction was seen. Patients with this mutation appear to have a predisposition for myocardial infarction.

Activated Protein C Resistance↗
PubMed2004

Immediate Risk-Stratification Improves Survival (IRIS): study protocol.

BACKGROUND: To date, the implantable cardioverter-defibrillator (ICD) has been shown to be effective for primary prevention of sudden cardiac death only in selected groups of patients in the chronic phase after myocardial infarction. METHODS AND RESULTS: The Immediate Risk-Stratification Improves Survival (IRIS) Study compares ICD therapy with no ICD therapy in selected high risk patients early after myocardial infarction. Special emphasis is placed on optimal acute and long term medical therapy in all patients including metoprolol CR/ZOK. The hypothesis is tested that use of the ICD reduces overall mortality. For that purpose, consecutive acute ST elevation or non-ST elevation myocardial infarction patients are collected in a registry. From this denominator, patients are screened, and enrolled early after myocardial infarction (day 5 to day 31) if they exhibit both a reduced left ventricular ejection fraction < or =40% and a heart rate > or =100 bpm on the first available electrocardiogram (criterion I), or non-sustained ventricular tachycardia at a rate > or =150 bpm during Holter (criterion II). CONCLUSIONS: IRIS is a large scale prospective, randomized trial to evaluate the benefit of ICD therapy for reduction of total mortality in patients considered at high risk of sudden death early after acute myocardial infarction.

Clinical Protocols↗
PubMed2004

T wave spectral variance for noninvasive identification of patients with idiopathic dilated cardiomyopathy prone to ventricular fibrillation even in the presence of bundle branch block or atrial fibrillation.

Conventional methods using Holter ECG recordings for noninvasive risk stratification are limited in patients with idiopathic dilated cardiomyopathy (IDC) prone to ventricular fibrillation (VF) having atrial fibrillation (AF) or bundle branch block (BBB). We therefore investigated, whether spectral assessment of beat-to-beat alternations of repolarization is associated with VF in these patients. Twenty-four-hour Holter ECG recordings in 462 patients with IDC were used. The VF group comprised of 64 consecutive patients who survived cardiac arrest, the no VF group consisted of 398 consecutive patients without a history of malignant ventricular arrhythmia. One hundred patients with ischemic cardiomyopathy (ICM) served as a control group. In each patient, 1,024 consecutive T waves were aligned using cross correlation methods. Two-dimensional Fourier transform (2D FFT) used the data matrix of 1,024 consecutive 200-ms segments centered to the T wave peak. Power spectra of the 2D FFT revealed the frequency content of the T wave in the first dimension and the periodicity of this frequency content in the second dimension. The ratio between periodic frequency contents and the sum of nonperiodic and periodic frequency contents between 0.5 and 50 Hz is equal to the T wave spectral variance (TWSV) index. Thus, TWSV index = 0 would mean that all 1,024 T waves are identical and TWSV index = 1 would mean that the 1,024 T waves are totally variable. The TWSV index was significantly higher in the VF group (0.93 +/- 0.14) than in the no VF group (0.53 +/- 0.13, P < 0.01). The best cutoff between the VF and the no VF group was achieved by using a TWSV index of 0.75 (sensitivity = 89%, specificity = 78%). No significant differences were observed between patients with and without AF or with and without BBB, and between patients with IDC and ICM. Even in the presence of BBB or AF spectral assessment of T wave alternations by TWSV index using 2D FFT in Holter ECG recordings, allows the identification of patients with IDC at risk for VF.

Algorithms↗
PubMed2004

Application of radiofrequency energy in surgical and interventional procedures: are there interactions with ICDs?

During surgical and interventional procedures, interference may occur between ICDs and electrical cautery or with the application of RF energy. This may lead to the false induction of ICD therapies or could even result in device malfunction, which represents a potential perioperative hazard for the patient. This study analyzed the intraoperative interactions in 45 consecutive ICD patients in reference to different surgical and interventional procedures. A total of 33 surgical operations (general surgery [n = 14], urologic [n = 5], abdominal [n = 10], gynecological [n = 2], thoracic [n = 1], neurosurgical [n = 1]) and 12 interventional therapies (RF catheter ablation [n = 10], endoscopic papillotomy [n = 2]) were performed. The ICD devices were all located in left pectoral position and consisted of 25 single and 20 dual chamber defibrillators. During the procedure, tachyarrhythmia detection (VF 296 +/- 20 ms, VT 376 +/- 49 ms) of the devices was maintained active (monitoring mode), only ICD therapies were inactivated. The indifferent electrode of the electrical cauter/RF generator was placed in standard positions (right/left mid-femoral position [n = 27/8], thoracic spine area [n = 10]). After the procedure, the ICD memory was checked for detections and for changes in the programming. There was no oversensing, reprogramming, or damage of any defibrillator caused by RF energy. Despite the lack of undesired interactions, ICDs should be inactivated preoperatively to assure maximum patient safety. However, should inactivation not be possible, or the achievement uncertain, electromagnetic interference is highly unlikely.

Adult↗
PubMed2004

Complete loss of ICD programmability after magnetic resonance imaging.

The purpose of this case report is to describe the effects of an MRI performed on a patient without realizing that an ICD has been previously implanted. After a few seconds of imaging the adversity was recognized and the examination was stopped immediately. The patient was not pacemaker dependent and had neither physical complaints nor electrocardiographic changes in the surface ECG. A consecutively performed ICD assessment showed a backup mode with standard parameters for pacing (VVI 50 beats/min) and arrhythmia detection and treatment. The device could not be programmed by the external programmer. With the exception of printing out the parameters, all software functions were no longer feasible. A device examination by the manufacturer after ICD replacement showed that a major portion of the device memory was corrupt. Even ICDs of a newer generation are susceptible to magnetic interference, with the danger of complete loss of programmability.

Brain↗