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[en] Tests were made on nineteen generators, comprising seventeen types from five manufacturers and including four programmable units, and x-ray energies of about 4 MeV. The bipolar generators suffered no measureable damage and radiotherapy patients using these would appear not to be exposed to any hazard. Nor were any of the generators using entirely CMOS circuitry, including the programmable types, affected. Generators using hybrid bipolar and CMOS circuitry were damaged by radiation exposure, the majority of these being Medtronic pacemakers. Transient recovery of function followed by total failure suggested that even a transient loss of function must be regarded as a precursor to permanent damage. This transient effect indicates that it is most likely the CMOS circuit element that is affected. (U.K.)
[en] We present a case of an uneventful dual chamber permanent pacemaker (PPM) implantation which, on the follow-up chest radiograph (CXR), was reported as good lead tip placement and no complications. The patient was re-admitted 7 months later. The PA CXR appearances were unchanged but, in the lateral projection, the ventricular lead tip was projected posteriorly within the heart, most likely within the LV. This was confirmed by CT showing the ventricular lead tip within the LV having passed through a patent foramen ovale (PFO).
[en] A simulator device is described for insertion in a living body, having particular advantage for intracardiac use comprising a housing having a body formed for transvenous or transarterial insertion, electrode means at the outer surface of said body, means included in said housing defining a pulsing circuit electrically connected with said electrode means and means for activating said pulsing circuit embodied in said housing, said activating means being free of physical connection with an outside power source and dependent for its function on the living body in which it is inserted
[en] To determine the left atrial longitudinal strain discrimination threshold of atrial fibrillation (AF) in patients with dilated cardiomyopathy (DCM). A total of 100 DCM patients and LVEF < 25% were included. Of them, 50 had sinus rhythm (SR), and 50 had AF. Patients with significant valvular disease, cardiac pacemakers and prosthetic valves were excluded. Speckle tracking echocardiography was performed to visualize the inferior and lateral walls of the left atrium as well as the interatrial septum. The Q-Analysis software was used to assess left atrial contractile strain (εCT) during the atrial systole and left atrial conduit strain (εCD) during the atrial filling. In SR patients analysis was P-wave timed. In AF patients the reference point was at 200 ms before the QRS complex on the surface ECG. The εCD was significantly higher in SR patients than in those with AF (9.68% vs. 4.7%; p = 0.0003). ROC analysis demonstrated that εCD less than 5.43% (AUC 0.95; 95% CI 0.905–0.995; p < 0.0001) together with εCT below − 1.97% (AUC = 0.97; 95% CI 0.46–1.00; p < 0.0001) identified patients with AF. In patients with LVEF < 25% and AF left atrial contractile strain analysis is feasible. In these patients both contractile and conduit strain values are significantly lower than in patients with preserved SR, and εCD below 5.43% and εCT less than − 1.97% distinguish SR from AF patients with LVEF < 25%.
[en] This nuclear thermocurrent generator to feed a cardic pacemaker should have higher life expectancy and reliability than was previously achieved. For this purpose a gettering arrangement is connected to be heat conducting immediately adjacent to the nuclear fuel arrangement in an evacuated casing. The gettering arrangement can be operated to activate at as high a temperature as possible, from 1210C to preferably about 2040C, so that a high vacuum is maintained. The current generating thermal column works at a temperature difference of 55.60C. As the cold end of the column is connected to the outer casing, and should be held to a mean body temperature of 37.80C, the hot side of the thermal column may only be heated to 93.40C. The temperature jump from 1210 or 2040 to 93.40 is produced by a thermal resistance inserted between the hot side of the thermal column and the fuel arrangement. It may consist of a spacer made of stainless steel or by a gap, while in this first arrangement the nuclear heat generator is situated between the gettering arrangement and the thermal column, another arrangement shows the gettering arrangement enclosed in the fuel arrangement and thermal column. Here the heat flows in one direction only, the required temperature gradient is produced by suitable construction of the heat contacts between the 3 elements. Detailed constructional and manufacturing data are given for both models. Plutonium oxide is welded into a double casing as heat generator, in example the casing is made of nickel alloy. 1/10 gram of plutonium supplies a thermal energy of 50m watts, which produces a thermal current of 300 to 400 micro watts at 0.3V. (RW)
[de]Dieser nukleare Thermostromerzeuger zur Speisung eines Herzschrittmachers soll hoehere Lebensdauer und Zuverlaessigkeit haben als sie bisher erreicht wurden. Hierzu wird eine Gettereinrichtung waermeleitend unmittelbar an die, in einem evakuierten Gehaeuse befindliche, Kernbrennstoffeinrichtung angeschlossen. Die Gettereinrichtung kann so zu ihrer Aktivierung auf einer moeglichst hohen Temperatur - 1210C bis, vorzugsweise, etwa 2040C - betrieben werden, sodass ein hohes Vakuum aufrecht erhalten bleibt. Die stromerzuegende Thermosaeule arbeitet mit einer Temperaturdifferenz von 55,60C. Da das kalte Ende der Saeule mit dem Aussengehaeuse in Verbindung steht und auf einer mittleren Koerpertemperatur von 37,80C gehalten werden soll, darf die heisse Seite der Thermosaeule nur auf 93,40C erhitzt werden. Der Temperatursprung von 1210 bzw. 2040 auf 93,40 wird durch einen zwischen heisse Seite der Thermosaeule und Brennstoffeinrichtung gelegten Waermewiderstand erzielt. Er kann durch einen Abstandhalter aus nichtrostendem Stahl oder durch einen Spalt gebildet werden. Waehrend bei dieser zuerst beschriebenen Anordnung der nukleare Waermeerzeuger zwischen Gettereinrichtung und Thermosaeule gelegt ist, zeigt eine andere Anordnung die Gettereinrichtung eingeschlossen von der Brennstoffeinrichtung und der Thermosaeule. Hier fliesst der Waermestrom nur in einer Richtung; die gewuenschte Temperaturstaffelung wird durch entsprechende Ausbildung der Waermekontakte zwischen den 3 Elementen hergestellt. Fuer beide Ausfuehrungen werden detaillierte konstruktive und fertigungstechnische Angaben gemacht. Als Waermeerzeuger wird Plutoniumoxyd in einer Doppelhuelse, beispielsweise aus einer Nickellegierung, dicht eingeschweisst. 1/10 Gramm Plutonium liefert etwa eine Waermeenergie von 50 mWatt, womit ein Thermostrom von 300 bis 400 μWatt bei 0,3 V erzeugt wird. (RW)
[en] This study proposes the cantilever design of piezoelectric energy harvester scavenging energy from blood pressure variation in cardiac cycle. The harvester could be a perennial source of power for a typical pacemaker. The concept of three cm long and 72 μm thin cantilever based energy harvester having natural frequency close to that of heartbeat has been proposed. Considering a huge difference between shear (d15) and transverse (d31) piezoelectric coefficient the harvester was operated in two different modes. A number of materials (single and polycrystalline ceramics) along with Pb[ZrxTi1−x]O3 (PZT-5A) were operated in transverse and shear modes. The maximum open circuit voltage found for all cases was ∼6 V which was yielded by Pb(Zn1/3Nb2/3)O3–(6–7)% PbTiO3 (PZN-PT) when operating in shear mode. Further, the optimum resistance was calculated for all the materials under study operating in d15 and d31 modes for a wide frequency range. It was found that the maximum power among all materials under study was given by PZN-PT which is ∼13 μW while operating in shear mode. Such high magnitude of power harvested is due to its giant d15 which is 6000 pC N−1 and is sufficient to power a typical pacemaker. (paper)