Transvenous demand Pacemaker Treatment for intermittent complete Heart Block in a Cat

A 13-year-old male neutered domestic shorthaired cat had repeated syncopal episodes over a 6 month period, which had variable duration and continued to increase in frequency. Intermittent ventricular asystole, due to complete heart block, and hyperthyroidism were documented. As the syncopal episodes did not respond to a 4-week medical treatment and symptoms became severe, a transvenous ventricular demand pacemaker system (VVIM) was implanted via the external jugular vein. The unipolar lead was tunneled subcutaneously and connected with the generator in a preformed ventral abdominal muscle pocket. During follow up of 18-months there were no recurrences of the syncopal episodes.

Successful pacing using a batteryless sunlight-powered pacemaker.

AIMS Today's cardiac pacemakers are powered by batteries with limited energy capacity. As the battery's lifetime ends, the pacemaker needs to be replaced. This surgical re-intervention is costly and bears the risk of complications. Thus, a pacemaker without primary batteries is desirable. The goal of this study was to test whether transcutaneous solar light could power a pacemaker. METHODS AND RESULTS We used a three-step approach to investigate the feasibility of sunlight-powered cardiac pacing. First, the harvestable power was estimated. Theoretically, a subcutaneously implanted 1 cm(2) solar module may harvest ∼2500 µW from sunlight (3 mm implantation depth). Secondly, ex vivo measurements were performed with solar cells placed under pig skin flaps exposed to a solar simulator and real sunlight. Ex vivo measurements under real sunlight resulted in a median output power of 4941 µW/cm(2) [interquartile range (IQR) 3767-5598 µW/cm(2), median skin flap thickness 3.0 mm (IQR 2.7-3.3 mm)]. The output power strongly depended on implantation depth (ρSpearman = -0.86, P < 0.001). Finally, a batteryless single-chamber pacemaker powered by a 3.24 cm(2) solar module was implanted in vivo in a pig to measure output power and to pace. In vivo measurements showed a median output power of >3500 µW/cm(2) (skin flap thickness 2.8-3.84 mm). Successful batteryless VVI pacing using a subcutaneously implanted solar module was performed. CONCLUSION Based on our results, we estimate that a few minutes of direct sunlight (irradiating an implanted solar module) allow powering a pacemaker for 24 h using a suitable energy storage. Thus, powering a pacemaker by sunlight is feasible and may be an alternative energy supply for tomorrow's pacemakers.

The first batteryless, solar-powered cardiac pacemaker

BACKGROUND: Contemporary pacemakers (PMs) are powered by primary batteries with a limited energy-storing capacity. PM replacements because of battery depletion are common and unpleasant and bear the risk of complications. Batteryless PMs that harvest energy inside the body may overcome these limitations. OBJECTIVE: The goal of this study was to develop a batteryless PM powered by a solar module that converts transcutaneous light into electrical energy. METHODS: Ex vivo measurements were performed with solar modules placed under pig skin flaps exposed to different irradiation scenarios (direct sunlight, shade outdoors, and indoors). Subsequently, 2 sunlight-powered PMs featuring a 4.6-cm2 solar module were implanted in vivo in a pig. One prototype, equipped with an energy buffer, was run in darkness for several weeks to simulate a worst-case scenario. RESULTS: Ex vivo, median output power of the solar module was 1963 μW/cm2 (interquartile range [IQR] 1940-2107 μW/cm2) under direct sunlight exposure outdoors, 206 μW/cm2 (IQR 194-233 μW/cm2) in shade outdoors, and 4 μW/cm2 (IQR 3.6-4.3 μW/cm2) indoors (current PMs use approximately 10-20 μW). Median skin flap thickness was 4.8 mm. In vivo, prolonged SOO pacing was performed even with short irradiation periods. Our PM was able to pace continuously at a rate of 125 bpm (3.7 V at 0.6 ms) for 1½ months in darkness. CONCLUSION: Tomorrow's PMs might be batteryless and powered by sunlight. Because of the good skin penetrance of infrared light, a significant amount of energy can be harvested by a subcutaneous solar module even indoors. The use of an energy buffer allows periods of darkness to be overcome.

Interventional Laser-assisted Extraction of an Infected Trapped Ventriculoatrial Shunt Based on Techniques for Pacemaker Lead Explantation.

We present a case of successful interventional laser-assisted extraction of an endovascularly trapped long-term implanted ventriculoatrial shunt in a patient with shunt-associated septicemia. This approach is based on modified techniques for explantation of pacemaker leads and might be considered an additional option for extraction of otherwise nonremovable trapped endovascular catheters in experienced centers.

Cytotoxicity evaluation of polymer-derived ceramics for pacemaker electrode applications.

Ceramics are known to be chemically stable, and the possibility to electrically dope polymer-derived ceramics makes it a material of interest for implantable electrode applications. We investigated cytotoxic characteristics of four polymer-derived ceramic candidates with either electrically conductive or insulating properties. Cytotoxicity was assessed by culturing C2C12 myoblast cells under two conditions: by exposing them to material extracts and by putting them directly in contact with material samples. Cell spreading was optically evaluated by comparing microscope observations immediately after the materials insertion and after 24 h culturing. Cell viability (MTT) and mortality (LDH) were quantified after 24-h incubation in contact with the materials. Comparison was made with biocompatible positive references (alumina, platinum, biocompatible stainless steel 1.4435), negative references (latex, stainless steel 1.4301) and controls (no material present in the culture wells). We found that the cytotoxic properties of tested ceramics are comparable to established reference materials. These ceramics, which are reported to be very stable, can be microstructured and electrically doped to a wide range of conductivity and are thus excellent candidates for implantable electrode applications including pacemakers.

Submicrosecond pacemaker precision is behaviorally modulated: The gymnotiform electromotor pathway

What are the limits and modulators of neural precision? We address this question in the most regular biological oscillator known, the electric organ command nucleus in the brainstem of wave-type gymnotiform fish. These fish produce an oscillating electric field, the electric organ discharge (EOD), used in electrolocation and communication. We show here that the EOD precision, measured by the coefficient of variation (CV = SD/mean period) is as low as 2 × 10−4 in five species representing three families that range widely in species and individual mean EOD frequencies (70–1,250 Hz). Intracellular recording in the pacemaker nucleus (Pn), which commands the EOD cycle by cycle, revealed that individual Pn neurons of the same species also display an extremely low CV (CV = 6 × 10−4, 0.8 μs SD). Although the EOD CV can remain at its minimum for hours, it varies with novel environmental conditions, during communication, and spontaneously. Spontaneous changes occur as abrupt steps (250 ms), oscillations (3–5 Hz), or slow ramps (10–30 s). Several findings suggest that these changes are under active control and depend on behavioral state: mean EOD frequency and CV can change independently; CV often decreases in response to behavioral stimuli; and lesions of one of the two inputs to the Pn had more influence on CV than lesions of the other input.

Novel Gq alpha isoform is a candidate transducer of rhodopsin signaling in a Drosophila testes-autonomous pacemaker.

DGq is the alpha subunit of the heterotrimeric GTPase (G alpha), which couples rhodopsin to phospholipase C in Drosophila vision. We have uncovered three duplicated exons in dgq by scanning the GenBank data base for unrecognized coding sequences. These alternative exons encode sites involved in GTPase activity and G beta-binding, NorpA (phospholipase C)-binding, and rhodopsin-binding. We examined the in vivo splicing of dgq in adult flies and find that, in all but the male gonads, only two isoforms are expressed. One, dgqA, is the original visual isoform and is expressed in eyes, ocelli, brain, and male gonads. The other, dgqB, has the three novel exons and is widely expressed. Remarkably, all three nonvisual B exons are highly similar (82% identity at the amino acid level) to the Gq alpha family consensus, from Caenorhabditis elegans to human, but all three visual A exons are divergent (61% identity). Intriguingly, we have found a third isoform, dgqC, which is specifically and abundantly expressed in male gonads, and shares the divergent rhodopsin-binding exon of dgqA. We suggest that DGqC is a candidate for the light-signal transducer of a testes-autonomous photosensory clock. This proposal is supported by the finding that rhodopsin 2 and arrestin 1, two photoreceptor-cell-specific genes, are also expressed in male gonads.

Radioisotope powered cardiac pacemaker program. Safety analysis: preliminary dose rate evaluation.

Prepared for U. S. Atomic Energy Commission by Nuclear Materials and Equipment Corporation, Apollo, Penn.

Wisconsin pacemaker pork program.

"September 1958"

Cuidar do doente com pacemaker transvenoso provisório: a realidade no Hospital Prof Dr Fernando Fonseca

O trabalho tem como objetivos perceber, desde 27 de abril de 2014 a 31 de Dezembro de 2014, quantas pessoas colocaram pacemaker provisório no Hospital Professor Doutor Fernando Fonseca, o número de dias que, em média, uma pessoa permaneceu com pacemaker provisório antes da implantação de um Pacemaker definitivo, a revisão da bibliografia dos cuidados de enfermagem na colocação e manutenção do pacemaker provisório e finalmente, a realização de um procedimento sobre os cuidados de enfermagem a ter com a pessoa com pacemaker provisório. Durante o espaço temporal estudado foram colocados pacemakers provisórios a 62 pessoas, tendo sido necessário implantar pacemaker definitivo a 41 dessas pessoas (66%) tendo sido esta a população alvo da pesquisa. Analisando a população alvo percebemos que cada pessoa teve em média 4,37 dias o pacemaker provisório, sendo que algumas implantaram o pacemaker definitivo no próprio dia enquanto que uma pessoa teve o pacemaker provisório 17 dias. A média de idades da população alvo era de 75 anos, com variância entre os 53 anos e os 92 anos. Os locais escolhidos para a colocação do pacemaker provisório foram as veias femoral e jugular, não tendo havido nenhum caso em que a via de acesso tenha sido a veia subclávia. O grande número de dias em que algumas pessoas permaneceram com o pacemaker provisório, a idade avançada de parte da população considerada, o facto de algumas das pessoas com pacemaker provisório não estarem internados no serviço de Cardiologia e os estudos e relatórios que consideram as infeções nosocomiais da corrente sanguínea como uma das infeções associadas aos cuidados de saúde que mais contribuí para a morbilidade e mortalidade nos hospitais, referindo ainda que um dos dois fatores extrínsecos mais significativos para o aparecimento de infeções nosocomiais da corrente sanguínea foi a existência de um cateter venoso central. Considerei que todos estes dados justificam a revisão da literatura atual existente sobre os cuidados de enfermagem durante a colocação e manutenção de um pacemaker provisório e a realização de um procedimento sobre a manutenção dos pacemakeres provisórios a ser aplicado transversalmente no Hospital Professor Doutor Fernando Fonseca.

Satisfação do utente, percepção da doença e atitudes face aos técnicos de saúde: estudo em utentes da consulta de seguimento de portadores de pacemaker e CDI.

Tese submetida como requisito parcial para a obtenção do grau de Mestre em Psicologia Aplicada Especialidade em Psicologia Clínica

Estudo eletrocardiográfico de equinos de salto sadios

Avaliou-se o eletrocardiograma de 100 equinos sadios praticantes de hipismo clássico modalidade salto, com idades entre 4 e 19 anos, sendo 61 machos e 39 fêmeas, com média de 516,3 kg. Observou-se frequência cardíaca média de 40,20 ±13,33 bpm, sendo o ritmo cardíaco mais freqüente o sinusal (56%). As alterações de ritmo cardíaco estiveram presentes em 38% dos animais estudados, sendo a mais presente o marcapasso migratório (22%), seguido de bloqueio atrioventricular de 2º grau (4%), bloqueio atrioventricular de 1º grau (3%), contração ventricular prematura (2%), contração atrial prematura (1%). Não se observou correlação entre as variáveis estudadas (freqüência cardíaca, ritmo e arritmias) e a capacidade atlética, a idade e o sexo. O escore cardíaco após analise estatística não diferiu entre os grupos quanto ao desempenho atlético, a faixa etária e o sexo. O escore cardíaco, nesta amostra, não se mostrou um parâmetro confiável para se predizer o futuro atlético ou o nível de treinamento do eqüino.