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Biomedical subjects

E Alt

Publications and source records attributed to E Alt.

103 records · Page 6Linked to original sources
PubMed1984

[Echocardiographic study for optimizing therapy with physiologic heart pacemakers--the relevance of mitral valve motion].

The hemodynamic effects of the AV-intervals 50, 150 and 250 ms were studied in 19 patients with VDD pacemakers and compared to VVI stimulation and 12 normal individuals. LV dimensions and systolic and diastolic time intervals were measured with echo-phonoapexcardiography. The amplitude of LV-contraction, LV enddiastolic diameter, PEP, LVET and PEP/LVET significantly improved with physiological pacing when compared to VVI-stimulation. The optimal AV-interval was 50 ms in 8 patients, 150 ms in 7 and 250 ms in 4. Mitral valve closure (128 +/- 13 ms) and PEP (193 +/- 19) were grossly delayed in comparison to normal individuals. With increasing AV-intervals PEP and the onset of rise in the apexcardiogram were not changed but mitral valve closure occurred earlier, being 128 +/- 13 ms at AV = 50, 82 +/- 36 ms at AV = 150 and 20 +/- 73 ms at AV = 250. Simultaneously LV-filling time normalized for cycle length decreased from 50 +/- 5% to 45 +/- 8% and 38 +/- 10% respectively. In the presence of early mitral valve closure there was a late mitral notch, which occurred 10 +/- 20 ms after the onset of rise of the apexcardiogram. Thus the onset of the isovolumic contraction period was defined. In patients with VDD pacemakers therefore, echocardiography allows measurements of LV function, of the late onset of systole, and of mitral valve closure, which depends on the previous PR-interval. These values need to be considered in programming the optimal AV-interval and cannot be derived from normal individuals.

Adult↗
PubMed1983

[Results and prognosis following heart valve replacement].

786 patients who underwent cardiac valve replacement between 1965 and 1982 were followed up. Early mortality rate was 7,3% for the total observation period and decreased to 3,2% for the last four years. Patients with aortic valve replacement had better results in regard to their functional improvement as well as in their survival rate compared to those with mitral- or multiple valve replacement. Early mortality was also influenced by age at time of surgery. Overall complication rate was 6,4% per patient year with thromboembolic and bleeding complications being the most frequent. Patients with aortic valve replacement had the lowest (5,5%), those with multiple valve replacement the highest (11,4%) complication rate. It was also significantly influenced by cardiac size independent from location of valve replacement. Patients who had a heart of normal size postoperatively had significantly less complications.

Adult↗
PubMed1983

[Survival and outcome after pacemaker implantation. Comparison of patients with sinus node syndrome, AV block and absolute bradyarrhythmia].

Survival chances of 2007 patients with pacemaker implantation were determined. For the group as a whole, five-year survival rate was 57%, ten-year survival rate 35%. The prognosis was significantly better in patients with sick-sinus syndrome than those with AV block or brady-arrhythmias. Those with sick-sinus syndrome had an expectancy which was comparable to that of the (age and sex matched) normal population, while those with brady-arrhythmia had a significantly worse ten-year survival rate (24.7%) compared with a normal population (47.8%), P less than 0.01. Since the survival rate in sick-sinus syndrome - with or without pacemaker - is not different to that of the normal population, improved quality of life by preventing symptoms should be balanced against the risk of pacemaker-produced complications when indications for pacemaker treatment are considered.

Adolescent↗
PubMed1983

An active optical sensor for monitoring mixed venous oxygen-saturation for an implantable rate-regulating pacing system.

Presently available physiologic pacing systems do not fully restore rate regulation, especially in respect to little or no atrial response to activity. Other biologic parameters, detected by sensors, may provide the physiologic responsiveness necessary to rate-regulating pacemakers. An optical sensor using mixed venous oxygen saturation may be the ideal parameter for such a pacing system. At present, further research is necessary to elaborate a suitable algorithm for optimal rate control.

Arrhythmias, Cardiac↗
PubMed1983

[Delayed atrial excitation following bifocal pacemaker stimulation].

A patient with drug-resistant ventricular tachycardia due to ischemic heart disease with severe left ventricular failure was successfully treated by the implantation of a DDD pacemaker system pacing at a rate of 90 beats/min (overdrive suppression). Additional therapy with high doses of beta-blockers was necessary. The ECG demonstrated a delay of 100 ms between atrial spike and p-wave. The hemodynamic effects of this ineffective atrial contraction were assessed by jugular venous puls tracing, phonocardiography, echocardiography, and radionuclide-ventriculography. The desired positive effects of physiological pacing could only be achieved by further prolongation of the A-V interval by these 100 ms. This observation shows that, with DDD pacemakers, AV intervals of varying length may be necessary with VAT or VDD and DVI modes in individual cases.

Echocardiography↗
PubMed1981

Treatment of acute left heart failure using dobutamine and intraaortic counterpulsation. Animal experiments and first clinical experiences.

Ten anesthetized mongrel dogs had a left anterolateral thoracotomy; the left anterior descending coronary artery was then ligated. After 60 min five animals each were treated either with dobutamine (4 microgram/min/kg; for 10 min), or with dobutamine and intraaortic counterpulsation. Combined treatment of cardiogenic shock proved superior. Those five dogs had significantly lower heart rates and dp/dt/p-values. Due to IABP the non-ischemic parts of the left ventricle were better perfused; there was no difference in treatment with regard to ischemic parts. The combined treatment was successfully inaugurated in two patients with cardiogenic shock.

Adult↗
PubMed1980

[Removal of infected entrapped pacemaker electrodes by continuous traction (author's transl)].

To remove an infected pacemaker system in order to control the infection is often difficult when there is extensive connective-tissue fixation of the electrode. Forced manual extraction may lead to severe complications. For this reason, operative removal, in certain circumstances involving cardiotomy under extracorporeal circulation, has been practised. An alternative is continuous traction in which the probe is attached peripherally and by continuous traction removed from its cardiac attachment. Nine patients have been treated successfully by this method. In eight the electrode was removed within 1-10 days without significant complications. In one instance the electrode-catheter tore within the superior vena cava after 18 days of continuous traction; the remaining catheter, about 12 cm long, was removed with a sling catheter.

Aged↗
PubMedDate not supplied

Antithrombotic stent coatings: hirudin/iloprost combination.

Neointimal formation after stent implantation can cause luminal narrowing, called restenosis. Restenosis is induced by initial platelet adhesion and thrombus formation followed by immunocyte adhesion on the stent surface and on the injured vessel wall. The thrombus releases factors, which activates the proliferation of smooth muscle cells. Stents, coated with an antithrombotic surface, may prevent platelet adhesion and subsequent smooth muscle cell proliferation. This paper will review stent coating with poly-LD-lactic acid, a biodegradable polymer containing Iloprost, a synthetic prostacycline, and PEG-Hirudin as a method for reducing of restenosis.

Animals↗
PubMedDate not supplied

Central venous blood temperature for rate control of physiological pacemakers.

In 17 pacemaker patients and 14 volunteers we studied the behaviour of central venous blood temperature and heart rate under different kinds of exercise. Data were recorded by means of 5F catheter placed at the right ventricle. Temperature was measured with a thermistor incorporated in the lead. We found the increase in central venous blood temperature to be dependent on the individual exercise capacity and work load performed. The maximum temperature increase seen was 1.7 degrees Celsius. Subjects with lower physical fitness showed a more pronounced increase in temperature and heart rate compared to more physically fit subjects at the same work load. Due to its close relationship to metabolic and circulatory parameters, central venous blood temperature represents an appropriate signal to control the rate of physiological pacemaker systems. A special algorithm also using the initial dip for rate control has been incorporated into a pacemaker system, that is currently under clinical investigation (Intermedics NOVA MR).

Adult↗