[Maintenance of AAI(R) mode at the time of generator replacement]. / Fortbestehen des AAI(R)-Modus zum Austauschzeitpunkt.

BACKGROUND: In isolated sinus node disease single lead atrial stimulation is recommended. However, an inherent risk includes emerging AV node disturbances with serious bradycardia in the follow-up. This possible scenario frequently results in the implantation of an additional ventricular lead. PATIENTS AND METHODS: In this single-centre retrospective study the interval between 1982 and 2007 was analysed. During this period a total of 6,309 antibradycardia pacemakers were implanted for the first time. Ten percent (n=631) of these devices were single lead atrial pacemakers for treatment of the sick sinus syndrome (SSS). In these 26 years 136 pacemaker replacement operations were performed. During this procedure a thorough reevaluation of the stimulation mode was done. RESULTS: In 80.6% (n=112) AAI(R) was continued, in 10.1% (n=14) the system was upgraded to DDD(R), and in 9.3% the mode was changed to VVI(R). There were no significant differences in the lifetime of the AAI(R) pacemakers up to the time of this operation: 7.9 vs 6.3 vs 7.0 years. CONCLUSION: The single lead atrial pacing mode in SSS is mostly safe also in the long term. A premature change of stimulation mode is rarely necessary.

Distinct factors correlating with adverse cardiac events after major vascular surgery.

INTRODUCTION: Cardiovascular complications remain the principal cause of both morbidity and mortality after major vascular surgery. The well-known coincidence between vascular disease and coronary artery disease provided the rationale for a detailed analysis of major perioperative cardiovascular complications in their relation to preoperative and intraoperative parameter METHODS AND PATIENTS: 90 patients scheduled to undergo either femoral-popliteal bypass (n = 74) or repair of an infrarenal aortic aneurysm (n = 16) were prospectively included in the study. All patients had no signs of unstable cardiac disease and required no cardiac testing. Both preoperative and intraoperative parameter were correlated to adverse cardiac events (cardiac death and myocardial infarction -MI). RESULTS: Univariate analysis identified the following parameter to be significantly related to cardiac complications: prior MI and intraoperative hypertension (systolic blood pressure above 200 mmHg). In contrast perioperative betablocker therapy was revealed to be protective. In multivariate analysis the history of MI and intraoperative hypertension correlated with poor cardiac outcome. CONCLUSIONS: Our results underline the importance of the individual history in predicting perioperative risk and corroborate the beneficial effects of long-standing beta-blocker therapy. Additionally the significance of stable intraoperative hemodynamic parameter is demonstrated.

The value of permanent follow-up of implantable pacemakers--first results of an European trial.

A clinical study investigates the use of Home Monitoring (HM) in pacemaker therapy. For 3 months patients are supervised by daily automatic HM messages. Endpoints are the technical feasibility and the clinical benefit of HM. Ninety three patients have currently been included and followed for 72 +/- 30 days. Three patients were excluded due to insufficient mobile net coverage at their living sites. For the other patients, 5311 of 5911 messages were successfully registered. Interrupts in the sequence of messages occurred 331 times. Two hundred ten of these (63%) lasted just 1 day, 14 interrupts (4%) lasted 5 or more days. Two patients did not show any interrupts, 34 patients (38%) had interrupts of 3 and more days. The clinical benefit of Home Monitoring was found in the remote detection of arrhythmia and lead dislocation.

Estimulaçäo com adaptaçäo de freqüência controlada pelo sistema nervoso autônomo - uma avaliaçäo clínica / ANS controlled rate-adaptive pacing: a clinical evaluation

Para o tratamento da incompetência cronotrópica, marcapassos com adaptaçäo em freqüência baseados em diferentes sinais de sensores têm sido desenvolvidos, visando restaurar o mecanismo fisiológico em malha fechada e utilizando informaçäo fornecida pelo sistema nervoso autônomo (SNA). A medida da impedância cardíaca unipolar permite a monitorizaçäo do estado de contraçäo do coraçäo, diretamente relacionado ao tônus simpático. Marcapassos uni ou bicamerais com sistemas responsivos controlados pelo SNA foram implantados em 262 pacientes em vários centros clínicos. Protocolos de exercícios clíncos, monitorizaçäo por Holter, testes de estresse psicológico e estudos adicionais visando uma variaçäo intencional do tônus simpático confirmaram a resposta fisiológica em freqüência para os vários tipos de mudanças hemodinâmicas.

Activation-induced peripheral blood T cell apoptosis is Fas independent in HIV-infected individuals.

T cell apoptosis has been proposed as an important contributor to the functional defects and depletion of T cells in HIV-infected individuals. However, the mechanisms involved in this apoptosis have not been elucidated. We recently showed that peripheral blood T cells from HIV-infected individuals are especially susceptible to Fas antigen-induced apoptosis. In this study we examine the role of Fas, CTLA-4, tumor necrosis factor (TNF) receptors (TNFR) and CD30, receptors known to be involved in T cell activation-induced cell death (AICD), in the spontaneous and activation (anti-CD3)-induced apoptosis of peripheral blood T cells from asymptomatic HIV-infected individuals. We report here that spontaneous and activation-induced T cell apoptosis cannot be inhibited by reagents that block interactions of Fas, CTLA-4, p55 and p75 TNFR and CD30 with their respective ligands. We also show that IL-12, IFN-gamma, IL-4 and IL-10 cannot modify spontaneous, activation- and anti-Fas-induced apoptosis. Anti-Fas preferentially induced CD4+ T cell apoptosis whereas AICD induced apoptosis equally in CD4+ and CD8+ T cells. We conclude that T cell AICD in HIV infection is not mediated by Fas, thus indicating that Fas-induced and activation-induced T cell apoptosis are independent mechanisms of apoptosis which may play different roles in the pathogenesis of HIV infection.

Fas antigen stimulation induces marked apoptosis of T lymphocytes in human immunodeficiency virus-infected individuals.

Apoptosis (programmed cell death) of T lymphocytes has been proposed as a mechanism which plays an important role in the pathogenesis of human immunodeficiency virus (HIV) disease. Activation of Fas (CD95) can either result in costimulation of proliferation and cytokine production or in the induction of apoptosis of T lymphocytes. This raises the possibility that Fas is involved in the observed T cell apoptosis during HIV disease. In this report we show that peripheral blood CD4+ and CD8+ T lymphocytes from HIV-infected individuals undergo apoptosis in vitro in response to antibody stimulation (cross-linking) of Fas at a much higher frequency than from uninfected controls. This anti-Fas-induced T cell apoptosis is markedly higher than spontaneous T cell apoptosis in HIV-infected individuals. Antibodies against other members of the tumor necrosis factor (TNF)/nerve growth factor receptor family such as CD27, CD30, CD40, 4-1BB, p55 TNF receptor, p75 TNF receptor, and TNF receptor-related protein did not result in any increase of T cell apoptosis above that spontaneously observed in HIV+ individuals. Anti-Fas-induced apoptosis was much higher in symptomatic HIV-infected individuals; and the magnitude of anti-Fas-induced CD4+ T cell apoptosis correlated inversely with peripheral blood CD4+ T cell absolute counts. Surface expression of Fas on T cells was also found to be higher in HIV-infected individuals. Resting and activated CD4+ and CD8+ T cells both underwent apoptosis in response to anti-Fas antibody. L-Selectin positive memory CD4+ T cells were especially susceptible to anti-Fas-induced apoptosis. These findings show that CD4+ and CD8+ T lymphocytes in HIV-infected individuals are primed in vivo to undergo apoptosis in response to Fas stimulation, suggesting that Fas signaling may be responsible for the T lymphocyte functional defects and depletion observed in HIV disease.

A nebulizer system for highly reproducible aerosol delivery.

The output characteristics of current nebulizer systems are influenced by factors such as inspiratory flow, temperature and relative humidity of the ambient air as well as surface tension of the nebulizing solutions. Due to the resulting alteration of droplet characteristics the delivery of aerosolized drugs is variable. A nebulizer system, the PARI IS-2, has been designed for the delivery of aerosolized potent drugs. It is characterized by a highly consistent aerosol output and a high proportion of droplet mass in the respirable range. Laboratory testing was performed with a Malvern Particle Sizer and by measurement of total and effective output rates. Preconditioned air was supplied to the system in order to simulate different inspiratory flows (steady state) at varying ambient conditions. There was only a small effect on droplet sizes (MMD 3.0 to 3.6 microns) over the investigated range of inspiratory flow, ambient conditions and drug solutions. Total and effective output rates of the nebulizer were found to be linearly proportional between 5 and 20 l/min inspiratory flow thereby compensating for the dilution of aerosol by entrained air. Total output, at a relative humidity between 20% and 80% and at fixed inspiratory flow, varied only by +/- 6% with respect to 50% relative humidity (r.h.). The proportion of the dose delivered from the system ranged from 28% to 67% for an initial fill volume between 0.5 and 3 ml, respectively. Thus, for standardized breathing and by using the manual interrupter for on-command therapy, a highly effective delivery and deposition of therapeutic aerosols in the lungs may be achieved with the PARI IS-2 nebulizer system.(ABSTRACT TRUNCATED AT 250 WORDS)

Right ventricular conductance to establish closed-loop pacing.

Innovations in pacing technology, which include the addition of rate-responsive features to programmable pacemakers, can improve the quality of life of patients suffering from sick sinus syndrome. Among the strategies providing rate-adaptive cardiac pacing, the most attractive is the physiological restoration of closed-loop chronotropic control. This paper describes how autonomic nervous system (ANS) control information is extracted from dynamic measures of myocardial contractile performance obtained from unipolar conductance measurements using the stimulation electrode in the right ventricular cavity. The pacemaker uses the ANS information to modulate pacing rate and restore normal physiological control of heart rate. A new algorithm, regional effective slope quantity (RQ), for isolating the ANS signal was developed. The resulting signal, ventricular inotropic parameter (VIP), is a normalized parameter proportional to the strength of the ANS inotropic signals to the myocardium. The efficacy of the ANS control concept was evaluated in multi-centre studies. Patients with AV block and VIP-controlled pulse generators performed defined exercise protocols. The ANS-controlled pacing rate and the spontaneous sinus rate were closely correlated. Blood pressure and subjective patient reports further indicated that good control of the cardiovascular circulation was achieved.

[Dilated myocardial disease as sequela of chronic Lyme carditis]. / Dilatative Herzmuskelerkrankung als Folge einer chronischen Lyme-Karditis.

A report is given on a 39-year-old man, who developed, after a tick bite, erythema, progressing symptoms and, after 3 years, showed the typical clinical and echocardiographic signs of a dilative cardiomyopathy. A serological test for Lyme Borreliosis was positive. Most of the symptoms disappeared after high-dose penicillin therapy.

Isolation of Legionella pneumophila serogroup 3 from pericardial fluid in a case of pericarditis.

A 43-year-old woman was hospitalized for fulminant pericarditis. During diagnostic work-up, an as yet unknown bronchial carcinoma was detected. In the pericardial exudate Legionella pneumophila serogroup 3 was demonstrated by direct fluorescent antibody technique and by culture. In a lung biopsy L. pneumophila serogroup 3 was found, too. Using an antigen-ELISA for L. pneumophila serogroup 1, antigenuria was demonstrated. In cases of pericarditis negative for common bacterial pathogens, all diagnostic tests for legionellae, e.g. culture, antigen detection in pericardial, pleural effusion and urine and antibody detection should be included in the diagnostic programme.

[Intracardiac recording of potentials in placing a thermodilution catheter]. / Intrakardiale Potentialableitung zur Plazierung eines Thermodilutionskatheters.

It is reported on methods of positioning our former described flow directed thermodilution (TD) catheter by the intracardiac ECG derived from two electrodes, one at the tip of the catheter near the temperature sensor and the other six centimeter proximally of it. The typical criterion of the intracardiac ECG in the outflow tract of the right ventricle and in the pulmonary artery are listed, especially the amplitudes, the QRS-splits, T-wave inversion and P-wave configuration.

[Lyme borreliosis--a possible cause of atrioventricular block]. / Lyme-Borreliose--eine mögliche Ursache von atrioventrikulären (AV-)Blockierungen.

Eight cases of Lyme borreliosis of clinical certainty with carditis are reported. In six patients, AV-blocks were predominant, two patients had a myopericarditis. Six acute cases were seropositive, but one case remained seronegative. The titer was border-line in that patient, who was studied 4 years after the acute disease. A Lyme carditis should be considered in each case, in which AV-blocks appear acutely.

[Physiologic frequency adaptation of cardiac pacemakers using systolic time intervals]. / Zur physiologischen Frequenzanpassung von Herzschrittmachern mittels systolischer Zeitintervalle.

Of the parameters in consideration for control of physiological rate responsive pacing special interest is directed to stroke volume. In search of indirect parameters which are correlated to stroke volume it is demonstrated on principle that systolic time intervals could be used. From the relation ejection time versus pre-ejection time (LVET/PEP) which is known for its correlation to stroke volume a simple algorithm is derived which is based on the realization that PEP is related to the reciprocal of cardiac output. First investigations with patients demonstrated the possibility of the computation of heart rate from PEP only, with good physiological significance.

[A new catheter for hemodynamic studies]. / Ein neuartiger Katheter für hämodynamische Untersuchungen.

It is reported on a new catheter technique for the determination of the cardiac output by means of the method of thermodilution. It consists of a thin sensorcatheter (3 Ch), which contains a microthermistor as temperature sensor and additionally two electrodes. The insertion of the catheter is carried out via puncture of the subclavian vein by means of a special introducer set, the outer sheath of which can used for injecting the cold solution. The positioning of the sensor catheter into the pulmonary artery may be done by intracardiac ECG monitoring with the help of the two electrodes. By means of these electrodes, however, also an electric stimulation of the right ventricle is possible, so that, for instance, haemodynamic investigations depending on stimulation parameters can be performed by only one catheter. The clinical test of the new catheter-set was very successful.