Purpose: Paper presents the results of the simulation of acoustic wave propagation in quasi one-dimensional multilayered structure. The purpose was to examine the influence of the thickness of two materials forming the transmission system, depending on the acoustic wave source frequency. Design/methodology/approach: To perform simulation, the FDTD (finite difference time domain) algorithm was used. An acoustic wave propagated through the system consisting of ten alternating layers of equal thickness, surrounded on both sides by air. On the edges of the simulation space Neumann boundary conditions were provided. Findings: Changing the layer thickness affects the position of the SPL minima and causes narrowing of the area of the total acoustic pressure curves. Research limitations/implications: The influence of changes in the thickness of the layers forming the quasi onedimensional multilayer system on transmission was investigated. In order to better know the transmission characteristics of the system consisting of two different materials, the effect of changing the physical size of heterogeneous layers should be examined. It would be also important to compare the simulation results with those obtained experimentally. Practical implications: Simulation of quasi one-dimensional multi-layer systems allows to design new materials adapted to the requirements of specific applications without the need to carry experiment. Multilayer systems can be operated in a variety of applications, primarily as a filter with adjustable band gap frequency intermittently, and also as a material for absorbing incident acoustic waves. Originality/value: The available literature contains a limited information on the propagation of acoustic waves in quasi one-dimensional multi-layer systems. This paper responds to the demand caused by the lack of available articles in this topic and enables view the findings of research for one of the simpler periodic structures.

Successful candidates of the 2008 HERMES European Examination in Adult Respiratory Medicine were invited to join a HERMES Diplomates Cocktail in September 2009 during the ERS Annual Congress, Vienna. The cocktail was a great opportunity for exam participants to exchange ideas and impressions among themselves and with representatives from the ERS School and the ERS Examination Committee. Dr Lutz Beckert, a practising physician in New Zealand, explained the reasons that led him to sit the examination: "Most important is the professional reason, thinking that after practicing for about 10 years, it's nice to get some benchmark on how you are actually doing. You get some successes with your patients, some successes with your research and you have no benchmark anymore because you've worked by yourself. And that was a very important professional activity..."Dr Beckert demonstrated his commitment to a lifetime of continuing professional development. Lifelong learning to ensure the best possible care for patients is defi nitely a motivation which is common to all exam participants. A further motivation frequently expressed was a desire for candidates to benchmark themselves against their peers and to identify their potential educational needs.

BACKGROUND:Minute ventilation sensors of cardiac pacemakers measure ventilation by means of transthoracic impedance changes between the pacemaker case and the electrode tip. We investigated whether this technique might detect sleep-related breathing disorders. METHODS AND RESULTS:In 22 patients, analog waveforms of the transthoracic impedance signal measured by the pacemaker minute ventilation sensor over the course of a night were visualized, scored for apnea/hypopnea events, and compared with simultaneous polysomnography. Analysis of transthoracic impedance signals correctly identified the presence or absence of moderate to severe sleep apnea (apnea/hypopnea index, AHI >20 h(-1)) in all patients (receiver operating characteristics, ROC=1.0). The ROC for AHI scores of > or =5 h(-1) and > or =10 h(-1) showed an area under the curve of 0.95, P<0.005, and 0.97, P<0.0001, respectively. Accuracy over time assessed by comparing events per 5-minute epochs was high (Cronbach alpha reliability coefficient, 0.85; intraclass correlation, 0.73). Event-by-event comparison within +/-15 seconds revealed agreement in 81% (kappa, 0.77; P<0.001). CONCLUSIONS:Detection of apnea/hypopnea events by pacemaker minute ventilation sensors is feasible and accurate compared with laboratory polysomnography. This technique might be useful to screen and monitor sleep-related breathing disorders in pacemaker patients.

Einleitung: Das Schlafapnoe-Syndrom (SAS) ist durch ein erhöhtes kardiovaskuläres Risiko charakterisiert. Garrigue, et al. 2002 berichten erstmalig über den Effekt einer nächtlichen Überstimulierung (Nocturnal Overdrive Pacing, NOP) auf den Apnoe-Hypopnoe-Index (AHI) bei Patienten mit einem DDD Schrittmacher. Ziel unserer Studie war die Analyse von Anzahl und Dauer der Apnoen/Hypopnoen bei SAS Patienten während Zweikammer oder atrialem Overdrive Pacing im Vergleich zum normalen Schrittmachermodus bei Spontanrhythmus.

Amiodarone-induced pulmonary toxicity has been described mostly in patients receiving large doses of the drug over prolonged periods. In this report, we describe the early onset of acute pulmonary toxicity leading to acute respiratory distress syndrome after a short course of amiodarone treatment following middle-lobe non-small-cell lung cancer resection.

Even though rate responsive pacemakers are able to regulate pacing rates based on sensor activity, they are set with a minimum rate that is not adjusted to provide rate decreases during sleep. The aim of this study was to evaluate the performance of the "Sleep Rate" feature, as com pared to patient diaries and a validated method that identifies sleep from wrist actigraphy. In 19 patients (15 men; age 69 +/- 8 years) with Pacesetter Trilogy DR + pacemakers, the base rate and the sleep rate were set to 80 and 50 ppm, respectively. When the patients returned 2 days later, data recorded by the pacemaker and wrist actigraph were analyzed to find the agreement in corresponding sleep/wake periods. In 17 (89%) patients, the pacemaker went into the sleep mode. The total sleep time derived from actigraphy significantly exceeded the time during which the pacemaker was in sleep mode (1156.8 +/- 83.4 vs 307.3 +/- 77.2 minutes). Frequent reversions out of the sleep mode limited the total sleep time derived from the pacemaker. Cumulative analysis of the pacemaker data showed that the maximum time in the sleep mode was 78 minutes, and exceeded 1 hour in six instances, 30 minutes in 32 instances, and 15 minutes in 83 instances. Epoch by epoch comparisons revealed a good agreement (93.6 +/- 1.8%) during wakefulness between the corresponding actigraph and pacemaker epochs. However, only 24.6 +/- 3.7% of the corresponding epochs during sleep were identical, and the overall agreement was 54.4 +/- 3.7%. Except for one patient who reported palpitations, patients did not suffer from a pacemaker rate change. The Sleep Rate feature provides rate reduction during sleep, while assuring rapid frequency response during physical activity. However, the current algorithm does not allow long periods of slow pacing rate during continuous sleep, possibly due to its conservative design and the presence of movement arousals, which has to be improved in future generation algorithms.