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Biomedical subjects

P R Lichtlen

Publications and source records attributed to P R Lichtlen.

11 recordsLinked to original sources

[Results and experiences of transvenous endocardial defibrillator therapy].

We studied the follow-up of 72 patients who underwent implantation of a transvenous defibrillation lead system (ELS) (Endotak, CPI). All patients had ventricular tachycardia (VT) or fibrillation (VF) refractory to antiarrhythmic drug therapy. There were 51 patients with coronary disease and 21 patients had non-ischemic VT/VF. ELS was combined with a subcutaneous patch in 52 patients and implanted alone ("single lead only") in 20 patients. 40 patients received the ELS combined with antitachycardia pacing devices (Ventak PRx, CPI; Cadence, Ventritex) and 32 patients with the Ventak P 1600 or P2, CPI. Implantation of the ELS was attempted in 80 patients and performed in 72 patients (90%): Intraoperatively, the mean defibrillation threshold (DTF) was > 25 Joule (J) in five patients and no reliable ELS position was possible to achieve in three patients. These eight patients underwent thoracotomy with epicardial patch implantation. The mean DFT was < or = 20 J in all 72 patients with a mean DFT of 14 +/- 8 J in VT patients and 17 +/- 10 J in VF patients. Two of 80 patients (3%) died: one patient died intraoperatively and one during the mean follow-up of 6 +/- 2 (< 1 to 18) months. Complications occurred in three patients (4%): Dislocation of the Endotak electrode was observed in two patients (3%) and one patient developed pneumothorax postoperatively. Our data show that the ELS is most suitable in the majority of patients with VT/VF and is the approach of first choice for cardioverter defibrillator implantation at the present time. However, despite a relatively low intra- and perioperative complication rate, this approach should not be performed in institutions without cardiac surgery.

Adolescent

Thermocardiography--a method for continuous assessment of myocardial perfusion dynamics in the exposed animal and human heart.

In the exposed animal and human heart, coronary flow reduction results in a significant decrease of regional myocardial temperature. Epicardial temperature can be recorded instantaneously by the use of thermography. In contrast to other techniques, this method allows continuous assessment of rapid coronary flow changes and shows exactly the extent of myocardium involved. Value and limits of thermocardiography in animal experiments and during coronary bypass surgery are discussed and typical examples of myocardial thermograms obtained at various interventions are shown.

Animals

[Isosorbide-dinitrate in myocardial perfusion (author's transl)].

UNLABELLED: The effect of isosorbide dinitrate (ISDN) (10 mg sublingually) on myocardial perfusion during ischemic conditions was analyzed in 14 patients with angiographically severe coronary artery disease and typical angina pectoris, using the 201-Thallium-myocardial scintigraphy. All patients underwent two identical scintigrams with the same work load during bicycle ergometry; a control scintigram leading to angina and ST-depressions of greater than 0.1 mV was followed 4--6 weeks later by a scintigram after ISDN; all drugs -- except sublingual nitroglycerin -- were withheld for an entire week. -- RESULTS: 25 of 39 new or enlarged, exercise-induced defects (64%) were normalyzed after ISDN; 14 new or enlarged defects remained unchanged (p less than 0.0005). In the 11 patients, in whom ISDN led to complete abolishment of angina, 23 of 30 new defects (76%) were normalized against none in the 3 patients with persistent angina and ST-depressions. Quantitation of perfusion was attempted by calculating the average impulse rate (counts/min/matrix point): in those patients reacting favorably to ISDN average impulse rate decreased significantly especially in the normal area (p less than 0.001), resulting in a more homogeneous distribution of Thallium activity, indicating a marked reduction in local oxygen consumption.

Adult

[Incidence of ventricular arrhythmias after aneurysmectomy (author's transl)].

Incidence and type of premature ventricular contractions (PVC) were studied by ambulatory monitoring in 66 patients at the average 20 months after left ventricular aneurysmectomy. In 25 of these patients long-term-Ecg-monitoring was obtained before and after surgical intervention. After aneurysmectomy only 30% of all patients showed no PVCs; 35% had few PVCs and 35% demonstrated frequent PVCs. In 16 patients (24%) PVCs of Lown Classes III and IV were found. Only 7 out of 25 patients of the group analyzed before and after aneurysmectomy improved by one or more Lown Classes, 10 patients remained in the same Class, 8 patients worsened. In 11 patients ventricular arrhythmias refractory to medical treatment were the indication for aneurysmectomy. There were three in-hospital deaths. Of the remaining 8 patients only two became free from ventricular ectopic activity, 5 continued to have frequent multifocal PVCs, two of them required repeatedly DC-cardioversions. In two patients sudden cardiac death occurred two and three years after aneurysmectomy. It is concluded that only a small percentage of patients with left ventricular aneurysm gets free from ventricular ectopic activities after aneurysmectomy. Results of aneurysmectomy for intractable ventricular arrhythmias are disappointing and unpredictable. The application of new surgical techniques to localize and excise irritable foci seems advisable for the future.

Adult

Invited commentary.

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Electrocardiography

Clinical application and results of the assessment of coronary blood flow by the regional precordial xenon residue detection technique.

Methodological and technical aspects as well as application and results of the precordial Xenon-residue-detection technique are critically reviewed. The results concern mainly normal flow in various regions of the heart esp. in the free wall of the right and left ventricle, poststenotic flow in patients with coronary artery disease in relation to the degree of proximal narrowings as well as wall motion of the corresponding LV segment, bypassgraft flow and flow after drug interventions esp. nitrates, betablockers, the calcium-antagonist Nifedipine and the coronary dilator Dipyridamole. In spite of its serious limitations (high affinity of Xenon for fatty tissue, geometrical problems in the assessment of flow and its relation to anatomy, gas exchange in situations of high flow etc.), the technique is found to be a useful investigatory tool. Due to its technical display and the related high costs routine application is, however, prohibitive.

Cardiomyopathies

[Surgical interruption of the accessory pathway in a case of WPW-syndrome with persistent supraventricular tachycardia provoked by sinus node suppression (author's transl)].

This is a case report of a 60-year-old woman with a WPW-syndrome Type A developing persistent supraventricular tachycardia refractory to medical treatment. The re-entry mechanism was based on av-junction escape beats leading to retrograde conduction through the accessory pathway in presence of sinus node dysfunction i.e. long periods of sinus arrest probably enhanced through antiarrhythmic drug therapy and/or digitalis. With the aid of electrophysiological examinations and intraoperative epicardial mapping the accessory pathway was located in the upper lateral region of the left ventricle and interrupted by an incision in the av-groove from inside of the lfet atrium. Although an additional accessory pathway, not interrupted by surgery was suggested by the postoperative electrophysiological study, the patient remained free from tachycardia over more than 18 months, except for one episode terminated promptly by overdrive pacing from the right atrium. Postoperatively sinus bradycardia and av-junctional escape rhythm prevailed.

Accessory Nerve

[Hemodynamic comparison of Starr-Edwards, Lillehei-Kaster and homograft valves in the mitral position (author's transl)].

In 16 patients with Starr-Edwards (SE) disc valves, 10 patients with Lillehei-Kaster (LK) valves, and 4 patients with fresh aortic homografts (HG) in the mitral position the hemodynamic qualities of the valves were studied. All three valve types in general showed similar results, but they differed clearly as far as special parameters are concerned. So SE valves had the highest pressure gradients, HG valves the lowest, whereas LK valves were in between. The results of the study lead to the conclusion that tilting disc valves implanted in the mitral position are the best compromise, since they are always available and their hemodynamic response can be tolerated.

Angiocardiography