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Biomedical subjects

W Jung

Publications and source records attributed to W Jung.

At least 163 records · Page 9Linked to original sources
PubMed1995

[Junctional arrhythmias in radiofrequency modification of the atrioventricular node].

UNLABELLED: Accelerated junctional rhythm (JR) is known as a response of the atrioventricular node to thermal injury and a common finding in radiofrequency ablation for AV node reentrant tachycardia. We studied JR during 1314 radiofrequency current deliveries in 172 patients with AV node reentrant tachycardia or paroxysmal atrial fibrillation in relation to the ablation result. JR in a successful RF delivery were characterized by cycle length and conduction. RESULTS: Selective slow pathway ablation was performed in 100 patients (Group A), selective fast pathway ablation in 41 patients (Group B), and total AV junction ablation in 31 patients (Group C). A successful radio-frequency ablation without JR was rare (sensitivity: 98.8%; specificity: 51.2%). JR during slow pathway ablation had a longer cycle length (X +/- SD; CL: 494 +/- 138 ms) and a lower cycle length dispersion (delta CL: 178 +/- 199 ms) than JR during fast pathway ablation (CL: 399 +/- 108 ms; delta CL: 345 +/- 145 ms) or before total AV block (CL: 439 +/- 163 ms; delta CL: 338 +/- 195 ms). JR with bundle branch block aberration or ventriculoatrial block were more often found in group B and group C than in group A (BBB: 29% vs. 23% vs. 12%; VA-Block: 80% vs. 82% vs. 33%). Group B and group C did not differ significantly. CONCLUSION: JR leading to fast pathway ablation or heralding total AV block are characterized by a short cycle length, wide cycle length dispersion, and predominantly present ventriculoatrial block. Thus, JR is a useful marker to prevent inadvertent AV block in slow pathway ablation.

Adult↗
PubMed1995

[Sleep-related respiratory disorders in patients with implantable cardioverter/defibrillator devices--relationship between left ventricular function and respiratory disorder].

In order to detect sleep related breathing disorders (SRBD), 15 patients (6 with dilated cardiomyopathy [DCM], 9 with coronary heart disease [CHD], mean age 58 +/- 13 years) with implantable cardioverter/defibrillator [ICD] underwent polysomnography. A SRBD could be diagnosed in 27% of cases (n = 4; 3 DCM, 1 CHD). The reduction of the ejection fraction (EF) (normal, mild-to-moderate and severe, respectively) and the quality of sleep-related disturbances (normal, obstructive, and central/periodic) were significantly associated. In addition, in patients with DCM, the reduction of the EF correlated significantly with the amount of nocturnal oxygen-desaturation.

Adult↗
PubMed1994

Cure of xenografted human tumors by bispecific monoclonal antibodies and human T cells.

Tumor immunotherapy should increase both the number of T cells that kill the tumor and the likelihood that those cells are activated at the tumor site. Bispecific monoclonal antibodies (Bi-mAbs) were designed that bound to a Hodgkin's tumor-associated antigen (CD30) on the tumor and to either CD3 or CD28 on the T cell. Immunodeficient mice were cured of established human tumors when mice were treated with both the CD3-CD30 and the CD28-CD30 Bi-mAbs and then given human peripheral blood lymphocytes that had been incubated with the CD3-CD30 Bi-mAb and cells that expressed CD30. The enrichment of human T cells within the tumor and the fact that established tumors can be cured may indicate in situ activation of both the T cell receptor and the costimulatory pathway.

Animals↗
PubMed1994

Interactions between drugs and devices: experimental and clinical studies.

It is important to understand the potential interactions between the implantable cardioverter defibrillator (ICD) and antiarrhythmic therapy in patients who receive pharmacologic therapy as an adjunct to ICD therapy. In our cohort of 101 patients, antiarrhythmic agents were prescribed in 67% of the patients during long-term therapy for the following reasons: to suppress ventricular tachycardia/ventricular fibrillation episodes (50%), to lower the rate of ventricular tachycardia (19%), to prevent supraventricular tachyarrhythmia (21%), and for other reasons (10%). The potential influence of antiarrhythmic drugs on the defibrillation threshold (DFT) is the most important issue. In animal studies lidocaine increased the DFT in a dose-dependent manner. Quinidine, procainamide, propafenone, and flecainide did not affect the DFT or, in some cases, led to a small increase. Sotalol even decreased the energy requirements for internal defibrillation. In a prospective investigation we were able to document a significant increase of DFT (from 14.1 + 3.0 to 20.9 + 5.4 J, p < 0.001) by the use of amiodarone (400 mg/day), whereas this effect was not found in patients who received mexiletine (720 mg/day). In conclusion, the DFT or the safety margin for defibrillation should be known before antiarrhythmic agents are administered to patients with an ICD. In case of a small safety margin, the DFT should be reassessed after antiarrhythmic drug therapy is begun.

Animals↗
PubMed1994

Clinical efficacy of shock waveforms and lead configurations for defibrillation.

A randomized, prospective comparison of the defibrillation efficacy of various shock waveforms and nonthoracotomy lead configurations was performed in five distinct patient groups undergoing implantation of a cardioverter defibrillator. In the first group using a bidirectional lead configuration, there was no significant difference in the mean defibrillation threshold (DFT) between simultaneous and sequential monophasic shocks (17.8 +/- 5.8 joules versus 17.3 +/- 2.7 joules). In the second group using a bidirectional lead configuration, the mean DFT was 21.9 +/- 7.3 joules with monophasic shocks and 14.9 +/- 5.0 joules with biphasic shocks (p < 0.001). In the third group using a unidirectional lead configuration, the mean DFT was significantly higher (p < 0.001) with monophasic shocks (22.1 +/- 4.2 joules) compared with biphasic shocks (15.0 +/- 5.4 joules). In the fourth group, an intraindividual comparison with monophasic shock waveforms showed no significant differences in DFT using either a bidirectional (21.3 +/- 5.8 joules) or a unidirectional (21.7 +/- 2.6 joules) lead configuration. In the fifth group, a simplified unipolar transvenous defibrillation lead system ("active can") demonstrated significant lower DFTs (9.7 +/- 3.8 joules) compared with a standardized unidirectional lead configuration (18.0 +/- 6.8 joules). It is concluded that: (1) there seems to be no significant difference in the DFT between simultaneous and sequential monophasic shocks; (2) biphasic waveforms require significantly less energy for defibrillation than their corresponding monophasic waveforms; and (3) the unipolar single-electrode defibrillation system is easy to implant and provides DFTs at energies comparable with epicardial lead systems.

Adolescent↗
PubMed1994

Heart rate during exercise: what is the optimal goal of rate adaptive pacemaker therapy?

The objective of minute ventilation (MV)-controlled pacemaker algorithms is to simulate the physiologic relationship of the sensed signal and the sinus node response during exercise. In our study we determined the relationship between heart rate and MV in healthy middle-aged subjects by measuring breath-by-breath gas exchange throughout peak exercise. Regarding several clinical limitations of peak exercise testing, we additionally evaluated whether a 35 W low-intensity treadmill exercise (LITE) protocol can be used as a substitute for peak exercise testing to determine the physiologic heart rate to MV slope. The results demonstrated that the heart rate to MV relationship is not linear throughout peak exercise but is curvilinear with a smooth logarithmic-type profile. To simulate this relationship, MV-based rate adaptive pacemakers should generate a decreasing heart rate to MV slope during higher levels of work. The heart rate to MV slope determined during the early, dynamic phase of low-intensity exercise represents the same slope derived from peak exercise below the anaerobic threshold. The low-intensity treadmill exercise protocol, with minimal patient effort, can thus be used as a substitute for peak exercise to optimize rate adaptive slope programming of MV-controlled pacemakers.

Algorithms↗
PubMed1994

Complications of pacemaker-defibrillator devices: diagnosis and management.

Treatment of resuscitated patients with implantable cardioverter defibrillators has become increasingly more common as a method for the prevention of sudden cardiac death. Major complications such as perioperative death (incidence 2% to 8%), infection (2% to 11%); and lead-related problems (3% to 27%) have been described in previous trials. In our experience with 140 patients, problems were related to leads (n = 11), the device (n = 2), pacing (n = 1), sensing (n = 13), and defibrillation function (n = 5). Additional problems that occurred during the perioperative period included infection (n = 11), hematoma, and seroma (n = 2). Thrombus formation along endocardial leads was observed in 13 of 62 (21%) patients. Different arrhythmias (n = 10), such as sinus tachycardia, atrial fibrillation, and nonsustained, slow or incessant ventricular tachycardia with shock delivery, were also detected. Surgical management (predominantly for the major problems) was used in 31 (48%) patients, drug treatment in 25 (39%), and reprogramming of the device in 24 (38%) patients. All of these problems can result in an increase in mortality rates. This article provides an overview of the complications of cardioverter defibrillator treatment and is based on both published data and our series.

Arrhythmias, Cardiac↗
PubMed1994

Predictors of outcome in patients with implantable transvenous cardioverter defibrillators.

The identification of patients who benefit most from implantable cardioverter defibrillator (ICD) therapy is of great interest. To find out if clinical variables, the signal-averaged electrocardiogram, and electrophysiologic study predict occurrence of appropriate ICD discharges and death, we followed-up on 76 patients after implantation of a transvenous ICD. During a mean follow-up period of 18.2 +/- 6.4 months, 29 patients (38.6%) experienced at least one appropriate episode. When these patients were compared with those who had either no therapy or inappropriate episodes, three variables were found to be significant in the identification of patients who experienced appropriate discharges: (1) The mean ejection fraction of patients who received appropriate discharges was 35.4% +/- 13.5% versus 45.1% +/- 15.3% in the other group (p < 0.05); (2) patients with appropriate therapy had sustained monomorphic ventricular tachycardia that was more likely to be inducible (75.9% vs 21.2%, p < 0.01); and (3) in patients with appropriate therapy ventricular fibrillation was less likely to be inducible (10.3% vs 25.5%, p < 0.05). The signal-averaged electrocardiograms were more often abnormal, but the differences were not significant. The total mortality rate in our patient group was 7.8%, with nonsudden cardiac death in four patients, noncardiac death in one patient, and sudden death in one patient. In our patient group a lower ejection fraction and inducible sustained monomorphic ventricular tachycardia were predictors of future ICD discharge after implantation. The survival rate after transvenous ICD implantation is excellent; a longer follow-up period is necessary to further define predictors of total mortality rate.

Cardiac Pacing, Artificial↗
PubMed1994

Intraoperative laser photocoagulation of ventricular tachycardia.

Mapping-guided laser photocoagulation was used as an intraoperative technique to treat ventricular tachycardia (VT) in patients with ischemic heart disease. Laser irradiation was delivered during VT to sites identified with local diastolic activation or, if VT was not inducible, to sites identified with delayed potentials during sinus rhythm. The group consisted of 12 male and two female patients who ranged in age from 41 to 74 years (mean, 59.9 years). All of the patients had experienced myocardial infarction before surgery; in eight cases myocardial infarction was associated with an anterior wall aneurysm, and in one case it was associated with a posterior wall aneurysm. Identified sites for laser irradiation were restricted to the endocardium in only four patients, whereas six patients showed endocardial and epicardial foci and four of them without circumscript aneurysm were subjected only to epicardial laser photocoagulation. Resection of an aneurysm was performed in nine patients, and additional bypass grafting (one to four grafts) has been performed in 10 patients. There were two perioperative deaths. Laser photocoagulation has proved to be an efficacious method for the surgical treatment of VT. It gives access to epicardial sites and, in particular, allows limited surgery in patients with restricted left ventricular function and no circumscript aneurysm.

Cardiopulmonary Bypass↗
PubMed1994

Patient acceptance of implantable cardioverter defibrillator devices: changing attitudes.

Clinical experience suggests that the implantable cardioverter defibrillator (ICD) can reduce sudden cardiac death and total mortality in patients with malignant ventricular arrhythmia who meet the selection criteria for implantation. In addition to surgical problems, patients are faced with psychological and social adjustments. Patient acceptance for such therapy is marked by perceived concerns regarding device discharge, life-style alterations, and complications. We included 57 patients with ICDs in a study of their acceptance of the device. Results of a specially designed questionnaire (state-trait personality inventory) showed that 47 of 57 patients felt that their symptoms improved with the ICD system, 32 were constantly aware of the device, and 24 patients acclimated to the ICD system within less than 2 months. With respect to the need for battery replacement, only 27 patients requested a repeat electrophysiologic evaluation, 20 patients stated fear of ICD discharges, 12 patients revealed physical discomfort from the device, and limited quality of life occurred in eight patients. Fifty-five of 57 patients answered that it was worth having an ICD device implanted, 30 (53%) patients returned to active life, and 56 (98%) would advise another patient to have an ICD implantation if necessary. In conclusion, in general, the acceptance of the ICD as a tool for management of life-threatening ventricular tachyarrhythmias is very high. Quality of life and patient acceptance are important criteria for successful ICD therapy in addition to the improved survival rate.

Attitude to Health↗
PubMed1994

Opposite effects of the CD30 ligand are not due to CD30 mutations: results from cDNA cloning and sequence comparison of the CD30 antigen from different sources.

CD30L, the ligand for the activation antigen CD30, is a member of the tumor necrosis factor family of cytokines. Binding of CD30L to CD30, which is a member of the nerve growth factor/tumor necrosis factor receptor family, induces proliferation in peripheral blood lymphocytes and Hodgkin's derived cell lines with a T-cell phenotype such as HDLM-2 and L540, while cell lines derived from anaplastic large cell lymphomas, such as Karpas 299, undergo cell death. In order to investigate whether mutations of the CD30 antigen are responsible for these opposite effects, we cloned the open reading frame of CD30 cDNAs from the cell lines L540 and Karpas 299 and from peripheral blood lymphocytes by reverse transcriptase polymerase chain reaction. Sequencing of independent plasmid clones revealed that these cells have a silent transition (A-->G) at position 771 of the open reading frame compared to the published sequence derived from the HTLV-1+ cell line HUT-102. As published data have shown that crosslinking of CD30 induces an elevation of cytosolic free calcium ([Ca2+]i) in TCR positive Jurkat cells, we have analysed the effect of crosslinking of CD30 on L540 and Karpas 299 cells. No elevations of [Ca2+]i have been observed in these cell lines after crosslinking of CD30 with HRS-4. We conclude (i) that the different functional effects of CD30 in PBL, L540 and Karpas 299 are not due to differences in the primary structure of the receptor; and (ii) that the different responses observed upon engagement with CD30L for the cell lines L540 and Karpas 299 do not correlate with differences in mobilization of [Ca2+]i after crosslinking of CD30.

Base Sequence↗
PubMed1994

Expression and functional interaction of hepatocyte growth factor-scatter factor and its receptor c-met in mammalian brain.

Hepatocyte growth factor-scatter factor (HGF-SF) is a pleiotropic cytokine with mito-, morpho-, and motogenic effects on a variety of epithelial and endothelial cells. HGF-SF activity is mediated by the c-met protooncogene, a membrane-bound tyrosine kinase. Here, we demonstrate that both genes are expressed in developing and adult mammalian brains. HGF-SF mRNA is localized in neurons, primarily in the hippocampus, the cortex, and the granule cell layer of the cerebellum, and it is also present at high levels in ependymal cells, the chorioid plexus, and the pineal body. c-met is expressed in neurons, preferentially in the CA-1 area of the hippocampus, the cortex, and the septum, as well as in the pons. In the embryonic mouse, brain HGF-SF and c-met are expressed as early as days 12 and 13, respectively. Neuronal expression of HGF-SF is evolutionary highly conserved and detectable beyond the mammalian class. Incubation of septal neurons in culture with HGF-SF leads to a rapid increase of c-fos mRNA levels. The results demonstrate the presence of a novel growth factor-tyrosine kinase signaling system in the brain, and they suggest that HGF-SF induces a functional response in a neuronal subpopulation of developing and adult CNS.

Animals↗
PubMed1994

Interleukin-7, interleukin-8, soluble TNF receptor, and p53 protein levels are elevated in the serum of patients with Hodgkin's disease.

In a search for specific serum markers with prognostic impact, we evaluated the clinical significance of IL-4, IL-7, and IL-8 as well as TNF receptor levels and soluble p53 in the serum of patients with untreated Hodgkin's lymphoma (HD). No elevations were observed for IL-4, while IL-7 and IL-8 were elevated in 15/52 (29%) and 21/78 (27%) patients, respectively. Soluble TNF receptors were detected in 16/29 patients (55%), and were significantly elevated in 6 (21%). P53 was detected in 21/33 (64%) patients. While IL-7 levels, detectable sTNF receptors, and p53 were not correlated with other obvious parameters, elevated IL-8 levels were associated with the presence of B symptoms (p < 0.002) and occurred more often in the nodular sclerosis form than in other histological subtypes (p < 0.02). Further investigations that correlate these serum parameters with the situation at the cellular level of an involved tissue will help to elucidate the enigmatic biology of HD.

Hodgkin Disease↗
PubMed1994

Persistence of a rheumatoid factor (RF)-producing B cell clone with a somatically mutated Ig kappa chain in a patient with rheumatoid arthritis.

The V kappa IV gene encoding the light chain of an IgA has been shown to have undergone 31 somatic mutations compared with the single existing V kappa IV germ-line gene. We now show the persistence of the rearranged and mutated DNA coding for this RF over a period of 5 years in the peripheral blood lymphocytes (PBL) of the patient with rheumatoid arthritis (RA). The sequence of the RF has been conserved to identity over this period. These results raise the possibility that the particular antigenic stimulus leading to RF production in this RA patient is active over a long period of time.

Arthritis, Rheumatoid↗
PubMed1994

Loss of late potentials after radiofrequency catheter ablation of recurrent ventricular tachycardia in a patient with right bundle branch block.

The case of a patient with a history of myocardial infarction and recurrent ventricular tachycardia undergoing attempted radiofrequency catheter ablation with loss of late potentials is described. Prior to energy delivery fractionated, late activation could be found using the signal-averaged ECG despite the presence of a right bundle branch block. After successful catheter ablation, the clinical ventricular tachycardia was no longer inducible and the signal-averaged ECG, recorded the next day, showed marked changes indicating loss of late potentials. Our report emphasizes the possibility of late potential recordings despite the presence of bundle branch block.

Aged↗
PubMed1994

Cyclooxygenase and lipoxygenase inhibition by BW-755C reduces acrolein smoke-induced acute lung injury.

Inhalation of smoke containing acrolein, the most common toxin in urban fires after carbon monoxide, causes vascular injury with non-cardiogenic pulmonary edema containing potentially edematogenic eicosanoids such as thromboxane (Tx) B2, leukotriene (LT) B4, and the sulfidopeptide LTs (LTC4, LTD4, and LTE4). To determine which eicosanoids are important in the acute lung injury, we pretreated sheep with BW-755C (a combined cyclooxygenase and lipoxygenase inhibitor), U-63557A (a specific Tx synthetase inhibitor), or indomethacin (a cyclooxygenase inhibitor) before a 10-min exposure to a synthetic smoke containing carbon particles (4 microns) with acrolein and compared the results with those from control sheep that received only carbon smoke. Acrolein smoke induced a fall in arterial PO2 and rises in peak inspiratory pressure, main pulmonary arterial pressure, pulmonary vascular resistance, lung lymph flow, and the blood-free wet-to-dry weight ratio. BW-755C delayed the rise in peak inspiratory pressure and prevented the fall in arterial PO2, the rise in lymph flow, and the rise in wet-to-dry weight ratio. Neither indomethacin nor U-63557A prevented the increase in lymph flow or wet-to-dry weight ratio, although they did blunt and delay the rise in airway pressure and did prevent the rises in pulmonary arterial pressure and pulmonary vascular resistance. Thus, cyclooxygenase products, probably Tx, are responsible for the pulmonary hypertension after acrolein smoke and to some extent for the increased airway resistance but not the pulmonary edema. Prevention of high-permeability pulmonary edema after smoke with BW-755C suggests that LTB4, may be etiologic, as previous work has eliminated LTC4, LTD4, and LTE4.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1994

[Methods, topography and mechanisms of radiofrequency ablation of AV-nodal reentry tachycardia].

Three different methods of radiofrequency catheter ablation of AV nodal reentrant tachycardia were investigated in 128 patients. Results, relapses, and complications using anterior approach (n = 15), moved catheter (n = 20), and posterior-inferior approach (n = 93) were compared. Eight mechanisms of ablation of AV nodal reentrant tachycardia were distinguished: 1) Ablation of fast pathway (n = 8), 2) of slow pathway (n = 22), 3) modification of fast (n = 12), 4) slow (n = 54), or 5) both pathways (n = 13), 6) Ablation of fast and modulation of slow pathways (n = 4), 7) ablation of slow and modulation of fast pathways (n = 12), and 8) ablation of both pathways (n = 3). The criteria of diagnosis of these mechanisms and a mapping grid of Koch's triangle were proposed. The fast pathway is located in the anterior septum in a region with identical amplitudes of atrial and ventricular deflections and the slow pathway could be found posteriorly in a more ventricular location. The anatomical location of the slow pathway differed more widely than the location of the fast pathway. The best method with lowest risk could be recommended as the ablation of the slow pathway. This method implicated the lowest incidence of complications. We observed relapses in 12 patients during control studies 30 min, 3-5 days, and 3-6 months after first ablation procedure. These arrhythmias could be ablated in a second attempt in eight and in a third procedure in four patients. With increasing experience the radiofrequency catheter ablation of AV nodal reentrant tachycardia will be the method of first choice in patients with recurrent tachycardia.

Adult↗