Retrospective analysis of reasons for failure of DDD pacemaker implantation in patients operated on between 1993 and 2005

Background: During implantation of a DDD pacemaker the following difficulties may be encountered: venous anomalies (the absence of vessels of adequate calibre or difficulty in subclavian vein puncture), arrhythmias during implantation (episodes of atrial flutter/fibrillation while the atrial leads are being positioned), lack of mechanical stability of the electrode in the heart chamber and inability to achieve an acceptable pacing and sensing threshold during implantation. The purpose of the study was to analyse retrospectively the reasons for DDD pacemaker failure in patients operated on between 1993 and 2005. Methods: We reviewed retrospectively all implantation data from 1988 to 2005 to identify patients with primary failure of DDD pacemaker implantation. Further analysis included patients who had received a DDD pacemaker between 1993 and 2005, when this type of pacemaker made up between 9 and 40% of all pacemaker implantations. We implanted 7469 pacemakers, including 1958 (26.2%) dual-chamber pacemakers, in 783 patients with atrioventricular block (AVB), 392 with sick sinus syndrome (SSS), 450 with AVB &#177; SSS and 333 with tachy-brady syndrome (TBS). The mean age of the patients was 65.5 &#177; 17.3 years. DDD pacing was unsuccessful in 108 (1.4%) patients, including 32 with AVB, 22 with SSS, 16 with SSS &#177; AVB and 38 with TBS. The mean age of these patients was 78.5 &#177; 19.4 years. Results: The reasons for failed implantation were venous anomalies in 12%, an arrhythmia episode in 27.8%, a high pacing threshold in the atrium in 17.6%, low atrial potential amplitude in 25.9% and lack of mechanical stability of the electrode in 16.7% of patients. The difficulties were encountered in elderly patients (p < 0.01), most frequently in patients with SSS and TBS (71). Between 2004 and 2005 venous anomalies and a high pacing threshold were the main causes of failure. Conclusions: Currently the main difficulties encountered during pacemaker implantation are venous anomalies and a high pacing threshold. Arrhythmia episodes, low atrial potential amplitude and lack of mechanical stability are of minor importance. Elderly patients with sick sinus syndrome and tachy-brady syndrome have the highest failure rate. (Cardiol J 2007; 14: 155-159

Retrospektywna analiza przyczyn niepowodzeń wdrożenia stymulacji typu DDD u pacjentów operowanych w latach 1993-2005

Wstęp: Podczas implantacji układu stymulującego typu DDD można napotkać na następujące trudności: anomalie żylne (brak naczynia o odpowiedniej średnicy, trudności w nakłuciu żył głównych); zaburzenia rytmu w trakcie zabiegu (napad trzepotania lub migotania przedsionków w czasie manewrowania elektrodą przedsionkową); brak mechanicznej stabilizacji elektrody w jamie serca; niemożność uzyskania przynajmniej granicznych akceptowalnych wartości parametrów sterowania i stymulacji w czasie implantacji. Celem niniejszej pracy było retrospektywne prześledzenie przyczyn niepowodzeń wszczepiania układu stymulującego typu DDD u pacjentów operowanych przez autorów w latach 1993-2005. Metody: Retrospektywnie w latach 1993-2005 przeanalizowano wszystkie protokoły operacyjne i starano się wyodrębnić pacjentów z niezrealizowanym pierwotnym zamierzeniem wszczepienia rozrusznika typu DDD. W dalszej analizie wykorzystywano dane z późniejszych lat (1993-2005), w których udział tych stymulatorów w ogólnej liczbie zabiegów wynosił 9-40%. W tym okresie wszczepiono 7469 rozruszników serca, w tym 1958 dwujamowych (26,2%) - z powodu bloku przedsionkowo-komorowego (AVB) u 783 osób, choroby węzła zatokowego (SSS) u 392, choroby dwóch węzłów (AVB &#177; SSS) u 450, zespołu tachy-brady (TBS) u 333 pacjentów. Średni wiek badanych wynosił 65,5 &#177; 17,3 roku. W tym czasie u 108 chorych (1,4%) nie udało się wdrożyć stymulacji typu DDD. W tej podgrupie wskazaniem do wszczepienia u 32 osób był AVB, u 22 - SSS, u 16 - SSS &#177; AVB, a u 38 chorych - TBS. Średni wiek wynosił 78,5 &#177; 19,4 roku. Wyniki: Przyczynami niepowodzenia u 12% chorych były anomalie żylne, u 27,8% - napad arytmii, u 17,6% - wysoki próg stymulacji w przedsionku, u 25,9% - niska amplituda własnego potencjału przedsionkowego oraz brak mechanicznej stabilizacji elektrody u 16,7% osób. Występowały one u pacjentów starszych (p < 0,01), a największą ich liczbę (n = 71) zarejestrowano u osób z SSS i TBS. W latach 2004-2005 dominowały anomalie żylne i wysoki próg stymulacji. Wnioski: Obecnie problem podczas implantacji stwarzają anomalie żylne i wysoki próg stymulacji, natomiast napad arytmii, niska amplituda potencjału przedsionkowego, brak mechanicznej stabilizacji mają mniejsze znaczenie. Największą częstość niepowodzeń rejestruje się u osób starszych z SSS oraz TBS. (Folia Cardiologica Excerpta 2007; 2: 230-235

Scintillator counters with WLS fiber/MPPC readout for the side muon range detector (SMRD)of the T2K experiment

The T2K neutrino experiment at J-PARC uses a set of near detectors to measure the properties of an unoscillated neutrino beam and neutrino interaction cross-sections. One of the sub-detectors of the near-detector complex, the side muon range detector (SMRD), is described in the paper. The detector is designed to help measure the neutrino energy spectrum, to identify background and to calibrate the other detectors. The active elements of the SMRD consist of 0.7 cm thick extruded scintillator slabs inserted into air gaps of the UA1 magnet yokes. The readout of each scintillator slab is provided through a single WLS fiber embedded into a serpentine shaped groove. Two Hamamatsu multi-pixel avalanche photodiodes (MPPC's) are coupled to both ends of the WLS fiber. This design allows us to achieve a high MIP detection efficiency of greater than 99%. A light yield of 25-50 p.e./MIP, a time resolution of about 1 ns and a spatial resolution along the slab better than 10 cm were obtained for the SMRD counters.Comment: 7 pages, 4 figures; talk at TIPP09, March 12-17, Tsukuba, Japan; to be published in the conference proceeding

LAGUNA in Polkowice-Sieroszowice mine in Poland

The Polkowice–Sieroszowice mine in one of the seven candidates for the future pan-European underground laboratory studied in the framework of the LAGUNA project. We review the evidence that from the point of view of geology, long-term plans for the mine and existing infrastructure, and support of the authorities this is a perfect place to host the 100 kton liquid argon detector GLACIER

The ICARUS T600 Experiment in the Gran Sasso Underground Laboratory

With a mass of about 600 tons of Liquid Argon (LAr), the ICARUS T600 detector is the biggest, up to now, LAr Time Projection Chamber (TPC). Following its successful test run, on the Earth surface, in Pavia (Italy) in 2001, the detector is now very close to start data taking in the Gran Sasso underground laboratory. The main features of the LAr TPC technique, together with a short discussion of some of the ICARUS T600 test run results, are presented in this paper

The LAGUNA design study- towards giant liquid based underground detectors for neutrino physics and astrophysics and proton decay searches

The feasibility of a next generation neutrino observatory in Europe is being considered within the LAGUNA design study. To accommodate giant neutrino detectors and shield them from cosmic rays, a new very large underground infrastructure is required. Seven potential candidate sites in different parts of Europe and at several distances from CERN are being studied: Boulby (UK), Canfranc (Spain), Fr\'ejus (France/Italy), Pyh\"asalmi (Finland), Polkowice-Sieroszowice (Poland), Slanic (Romania) and Umbria (Italy). The design study aims at the comprehensive and coordinated technical assessment of each site, at a coherent cost estimation, and at a prioritization of the sites within the summer 2010.Comment: 5 pages, contribution to the Workshop "European Strategy for Future Neutrino Physics", CERN, Oct. 200

The SMRD subdetector at the T2K near detector station

The T2K long-baseline neutrino oscillation experiment is running in Japan. The primary goals of the T2K are measurement of the mixing angle 13, and precise measurements of the mixing angle 23 and of the mass difference m2 23. The installation of the near detector complex was completed and first data were already registered. This article presents operation of the Side Muon Range Detector, a component of the Off-Axis near detector. Detector concept and implementation are presented, followed by a description of cosmic muon track reconstruction algorithm and finally current status