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Biomedical subjects

J Kreuzer

Publications and source records attributed to J Kreuzer.

At least 73 records · Page 4Linked to original sources
PubMed1989

[Susceptibility of frequency adapted cardiac pacemakers to dental treatment].

Two rate-responsive pacemakers (Activitrax and Sensolog) were tested in order to show up to which extent its function can be disturbed by dental treatment. Inhibition of the pacemaker occurred by switching the electrical dental appliance on and off, or by moving it back and forth. In most cases, inhibition was only evident when the distance between the pacemaker and the electrical appliance was less than 10 cm. The electrome proved to be the most potent source of disturbance, as the function of the pacemaker was totally inhibited when it was switched on and off with a frequency of 1 to 2 Hz and even at a distance of 2.8 meters. During dental treatment--especially osteotomies--vibrations are transferred upon the patient which can cause an increase of the pacing rate.

Dental Care for Persons with Disabilities↗
PubMed1988

Studies of the tissue reaction induced by transvenous pacemaker electrodes. I. Microscopic examination of the extent of connective tissue around the electrode tip in the human right ventricle.

The purpose of this study was to investigate the extent of connective tissue of the human right ventricle induced by cardiac pacing electrodes. Between January 1984 and July 1987, 34 consecutive patients with VVI-pacing systems were autopsied in the Department of Pathology at the University of Frankfurt/M. The surrounding tissue of these 34 electrodes (17 Siemens Elema 412 S, five Medtronic 6957, one Medtronic 6959, one Medtronic 4011, three Biotronik D2K, three Biotronik K 10, two Osypka FY 62, one Biotronik N, and one Siemens Elema 588) in the right ventricle were investigated histologically. The tissue was stained with Giemsa and the thickness of the connective tissue layer was measured. Stimulation threshold data at various times were known in four of eight screw-in electrodes, in seven of 17 vitreous carbon electrodes and in two of seven smooth surface electrodes. Electrode surface area, implantation time, age of the patient and cause of death were comparable for all three electrode groups. However, a significant difference was found in the extent of connective tissue between the porous surface and screw-in electrodes (128 +/- 55 vs 397 +/- 269 micron, P less than or equal to 0.01) and porous surface and smooth surface electrodes (128 +/- 55 vs 307 +/- 117 micron, P less than or equal to 0.01). No relation (r = 0.106) was found between the duration of implantation and the extent of connective tissue for the vitreous carbon electrodes (Siemens Elema 412 S).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Rate response during submaximal exercise: comparison of three different sensors.

Since 1983, 248 rate responsive pacemakers were implanted at our hospital. The main emphasis during clinical follow-up has to be placed on the adjustment and control of its rate adaption, to meet the requirements of the aged patient's daily life. Repeated submaximal exercise but not extreme strain, come to the fore. Kaltenbach's step test (individually by stencils defined normal ranges of the heart rate during a 6 minute submaximal exercise and a 6 minute recovery period; age and sex dependent work load relative to body surface area) is able to mimic everyday efforts in an easy and reliable way. Nineteen patients with QT-related pacemaker, 12 patients with respiratory dependent pacemaker and 45 patients with body activity directed pm Activitrax were exercised using kaltenbach's step test (mean wattage QT: 56 +/- 14, RDP: 75 +/- 29, Activitrax: 64 +/- 20). Fifty-two patients performed 3 rounds. In comparison, 42 patients with DDD-pm underwent the same test (75 +/- 28 Watt). The average curve (heart rate) with QT-pm settled in the normal range of the step test but was distorted. Only 42% of the patients reached normal range in all three rounds. The mean heart rate of the RDP-group bordered on the basis of the normal range. The average curve (heart rate) of patients with Activitrax or DDD settled exactly in the desirable range. Problems with the rate response under repeated exercise did not occur either in the RDP or in the DDD group. The rate response behavior of the QT-related pm, the RDP and the Activitrax was of different quality.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1988

Computer-assisted pacemaker management systems: three years of clinical experience.

The implantation of large numbers of cardiac pacemakers and the increasing sophistication in engineering techniques has resulted in the demand for computer-assisted pacemaker management systems to remain on top of the available programmable features of the pacers as well as being able to access the follow-up data of pacemaker patients. A pacemaker patient management systems is introduced (PA-TIENTLOG) that has been used in the clinical environment for a number of years. The menu-guided program is easy to handle and features a patient card for administration data, an implantation card for the technical data of the pacer, and a follow-up card where a large number of follow-ups can be stored side by side which are easily graphically displayable. An extensive statistical program, letter functions, automatic back-up and on-line communication with external equipment through an RS 232C interphase and a parallel adapter are available. The data base in Frankfurt holds 8,000 patients, 10,000 interventions and more than 30,000 follow-ups, the existing data base needs 20 M bytes storage space. Up to 96 different pacer types with their specific features can be introduced into the system. Software and hardware design complies with the recommendation of the NASPE Computer Committee.

Computers↗
PubMed1986

Increase in cardiac output with rate-responsive pacemaker.

Patients with myocardial insufficiency or patients during high cardiac work loads increase cardiac output (CO) only through an increase in heart rate (HR), which is not possible with a VVI pacemaker. This clinical study tests the hypothesis that the respiratory-dependent pacemaker (RDP) is able to increase CO by an increase in HR. A multiprogrammable RDP (BIOrate RDP 2, Alpha, Köln, West Germany) was implanted in 21 patients (16 men and 5 women) for ventricular pacing. The mean age of the patients was 68.1 +/- 9.5 years (+/- standard deviation). Since the RDP can be programmed either in the RDP or VVI mode, all patients served as their own control. During follow-up examinations 4 to 6 weeks after implantation, an exercise ECG and a determination of CO during rest and exercise using equilibrium-radionuclide ventriculography were performed. One pacemaker has had to be explanted because of "end of life." No other RDP is malfunctioning. There was a significant increase in HR in all patients during exercise with the RDP versus the VVI mode (105.5 +/- 5.9 versus 84.5 +/- 7.0 bpm; p less than 0.05). CO increased during exercise to 10.6 +/- 0.8 L/min (VVI mode) and 12.7 +/- 1.5 L/min (RDP mode) (p = not significant). RDPs are reliable systems for patients in whom dual-chambered pacemakers are contraindicated (e.g., patients with bradyarrhythmias). The RDPs are able to increase CO by 26 to 35% compared with the VVI mode because of an increase in HR.

Aged↗
PubMed1986

Rate responsive pacemakers: assessment after two years.

Rate responsive pacemakers (RRPM) for patients without sufficient response of the heart rate (HR) to exercise represent an alternative to improve cardiac output (CO) and capacity for exercise via an increase of HR. From 1983 until December 1985, we implanted 30 QT-related (TX), 25 respiratory dependent (RDP), and 35 body activity directed (ACT) pacemakers. The follow-up examination consisted of Holter-ECG, treadmill and/or bicycle workload, and determination of CO (TX: thermodilution technique, n = 11; 6 months after implantation. RDP: equilibrium radionuclide ventriculography, n = 13; 1 month after implantation). The capacity for exercise of patients with ACT was studied using a climbing step. Adaptation of HR could be achieved with TX, RDP, and ACT. There was a significant increase in CO during exercise TX or RDP versus VVI-mode (TX: delta = 1.7 l/min, RDP: delta = 2.1 l/min). Although all systems exhibited weak points, RRPM are reliable devices. We abide by using these pacemakers.

Aged↗
PubMed1986

Ambulatory pacemaker surgery--medical and economical advantages.

The first pacemaker implantation on an ambulatory basis was done in our hospital in 1980. Since then, approximately 1,000 pacemaker patients have been operated on as outpatients. In 1984, we performed 781 pacemaker operations including 624 ambulatory operations. 583 patients received ambulatory new implantations. 54 persons were supplied as outpatients with a dual chamber system, 31 with a rate responsive system. In order to avoid complications, we use a standardized procedure, especially because the operators change daily following a plan of rotation. Patients are observed for 3-4 h postoperatively before discharge. Complications due to ambulatory operating have not been noticed. The ambulatory implantation of single or dual chamber pacemakers has been proving true as a safe treatment in our clinic. The economical advantage is obvious. In 1984, 5,000 days of hospitalization could be avoided; complications attributable to hospital cross-infection, immobilization, etc. could be reduced.

Ambulatory Surgical Procedures↗
PubMed1985

Haemodynamic and antiarrhythmic protective effects of intracoronary perfusion during percutaneous transluminal coronary angioplasty.

In 17 anaesthetized open-chest pigs, experiments were performed to determine if a myocardial protective effect can be obtained by intracoronary perfusion through the dilatation catheter during balloon inflation for percutaneous transluminal coronary angioplasty. Placement of the catheter such that the balloon lay in the middle third of the left anterior descending coronary artery caused a significant deterioration in haemodynamic status prior to balloon inflation, and on 5 occasions led to the development of ventricular fibrillation (VF). Balloon inflation without perfusion for periods of up to 5 min produced further haemodynamic deterioration, and culminated in VF in 4/14 cases. Simultaneous perfusion during balloon inflation (proximal perfusion pressure 900-1200 mmHg), with flow rates of 14.5 ml min-1 for arterial whole blood and 21 +/- 7 ml min-1 for blood diluted with 0.90% NaCl (haematocrit approx. 25%), not only prevented the haemodynamic deterioration but resulted in an improvement compared with values obtained with the catheter in position prior to balloon inflation. In no case did VF occur during 5 min of balloon inflation plus perfusion. The use of diluted blood as the perfusate was not associated with intracatheter thrombus formation, which was sometimes seen as a complication of whole blood perfusion.

Angioplasty, Balloon↗
PubMed1985

Examination of explanted polyurethane pacemaker leads using the scanning electron microscope.

Since 1978, 2,365 polyurethane (PU) insulated cardiac pacing leads were implanted transvenously at our institution. To date, there have been no insulation failures in those leads. Thirty-seven PU leads were explanted, mainly for exit block, and 28 of these were investigated using the scanning electron microscope. We found a homogeneous distribution of surface changes in all lead segments in 56% of the 28 examined. These changes were more pronounced at the ligature site; severe surface cracking was noticed in 21%, with the deepest crack being 40 micron (average range of 10-15 micron). There appeared to be no time-dependency of the surface changes as indicated by regression analysis (r = 0.32, p greater than 0.05). The ultimate severity and outcome of this degradation process in the leads reported in this study will only be known in the future after longer use. We conclude that excess stress must be avoided during the implantation procedure and that careful surveillance is necessary.

Equipment Failure↗
PubMed1983

Polyurethane leads: facts and controversy.

A comparison of polyurethane and silicone cardiac pacing leads is presented. In comparing mechanical and electrical properties, friction coefficient and hydrolytic stability, both are highly qualified for use as electrode sheaths. The occurrence of surface cracking of polyurethane leads is examined. Several suggestions are proposed for dealing with the manufacture of new leads, the technique of implantation, and the follow-up required for successful surveillance.

Animals↗
PubMed1980

Three-year clinical experience with a new endocardial screw-in lead with introduction protection for use in the atrium and ventricle.

There is still a high incidence of dislodgement, threshold rises, and loss of sensing with permanent transvenous endocardial leads. Atrial leads are an even greater problem and require particularly reliable methods of fixation. In March, 1976 we reported our preliminary results from animal experiments using a new transvenous screw-in lead with introduction protection. This lead differs from other screw-in models as its spiral tip is retracted in the insulating tube during insertion. For fixation purposes a torque is applied to the proximal end of the conductor coil, which is loosely positioned within the tube, and this moves the helical electrode forward. One hundred and fifty endocardial electrodes have been implanted; 127 of them in the dilated ventricle and 23 in the atrium. The technique of introducing the lead into the vein (cephalic or jugular) was the same as that for conventional leads. It was easy to manage and quite uncomplicated. The fixation features in the atrium or the ventricle were sufficiently reliable to allow some patients to go home several hours post-implant. The total working time of the leads used has been 900 months; the overall complication rate is 2%.

Adolescent↗
PubMed1975

[Total electrode retraction (Twiddler syndrome) in infection of the pacemaker system].

We report upon a case of total retraction of an electrode (Twiddler syndrom) in an infected pacemaker battery. The silk-thread fixation was still fastened at the right place on the electrode; the tissue owing to the inflammation was no longer sufficient as a fixation point. The casues of this total retraction of the electrode are the following factors: the battery hat sufficient freedom of movement for rotation following exudation into the pacemaker cavity, the electrode was elastic and above all the pacemaker system was infected which could no longer guarantee a sufficient fixation of the electrode in the infected tissue. Attention is drawn to the necessity to remove an infected pacemaker system.

Aged↗