Clinical characteristics and outcome of infective endocarditis involving implantable cardiac devices.

CONTEXT: Infection of implantable cardiac devices is an emerging disease with significant morbidity, mortality, and health care costs. OBJECTIVES: To describe the clinical characteristics and outcome of cardiac device infective endocarditis (CDIE) with attention to its health care association and to evaluate the association between device removal during index hospitalization and outcome. DESIGN, SETTING, AND PATIENTS: Prospective cohort study using data from the International Collaboration on Endocarditis-Prospective Cohort Study (ICE-PCS), conducted June 2000 through August 2006 in 61 centers in 28 countries. Patients were hospitalized adults with definite endocarditis as defined by modified Duke endocarditis criteria. MAIN OUTCOME MEASURES: In-hospital and 1-year mortality. RESULTS: CDIE was diagnosed in 177 (6.4% [95% CI, 5.5%-7.4%]) of a total cohort of 2760 patients with definite infective endocarditis. The clinical profile of CDIE included advanced patient age (median, 71.2 years [interquartile range, 59.8-77.6]); causation by staphylococci (62 [35.0% {95% CI, 28.0%-42.5%}] Staphylococcus aureus and 56 [31.6% {95% CI, 24.9%-39.0%}] coagulase-negative staphylococci); and a high prevalence of health care-associated infection (81 [45.8% {95% CI, 38.3%-53.4%}]). There was coexisting valve involvement in 66 (37.3% [95% CI, 30.2%-44.9%]) patients, predominantly tricuspid valve infection (43/177 [24.3%]), with associated higher mortality. In-hospital and 1-year mortality rates were 14.7% (26/177 [95% CI, 9.8%-20.8%]) and 23.2% (41/177 [95% CI, 17.2%-30.1%]), respectively. Proportional hazards regression analysis showed a survival benefit at 1 year for device removal during the initial hospitalization (28/141 patients [19.9%] who underwent device removal during the index hospitalization had died at 1 year, vs 13/34 [38.2%] who did not undergo device removal; hazard ratio, 0.42 [95% CI, 0.22-0.82]). CONCLUSIONS: Among patients with CDIE, the rate of concomitant valve infection is high, as is mortality, particularly if there is valve involvement. Early device removal is associated with improved survival at 1 year.

Isolated congenital atrioventricular block diagnosed in utero: natural history and outcome.

BACKGROUND: Isolated congenital atrioventricular block (CAVB) diagnosed in utero is associated with a high morbidity and mortality. Prognosis is especially poor when heart rate drops below 55 beats per minute (bpm) and when fetal hydrops develops. We describe the natural history and outcome of 24 infants with isolated CAVB diagnosed in utero, review the literature, and assess the risk factors that could predict outcome. METHODS: This was a retrospective multicenter study of 24 patients with isolated CAVB diagnosed in utero. RESULTS: CAVB was detected at a mean gestational age (GA) of 24.7 +/- 5.1 weeks. Ten fetuses initially presented with complete heart block. Low heart rate or incomplete heart block was the first documentation of bradyarrhythmia in the other 14 fetuses. In 11 of them, CAVB developed during pregnancy after a median time of 3 (range 1-16) weeks. Fetal hydrops developed in 10 of 24 (42%) fetuses at a mean GA of 27.6 +/- 5.1 weeks. Hydropic fetuses showed lower heart rates during pregnancy (47 +/- 10 bpm) than non-hydropic fetuses (57 +/- 10 bpm). There were three intrauterine deaths; all were hydropic and female. Nine viable females and 12 males were born at a mean GA of 37.1 +/- 6.1 weeks with an average birth weight of 3097 +/- 852 g. Fifteen CAVB patients required pacemaker (PM) intervention, 10 of them immediately after birth. Dilated cardiomyopathy (DCM) developed in three infants of whom two died of congestive heart failure, shortly after the diagnosis was made; one is still alive. Mortality before or after birth was 21%, and was associated with heart rates below 50 bpm and development of fetal hydrops. Poor outcome, defined as death, PM implantation, or development of DCM, occurred in 83% of cases and was associated with heart rates below 60 bpm during pregnancy. CONCLUSIONS: Isolated CAVB diagnosed in utero is associated with high morbidity and mortality. Patients who develop fetal hydrops show lower heart rates during pregnancy than patients who do not. A fetal heart rate below 50 bpm and development of fetal hydrops is associated with increased mortality. Rates below 60 bpm are associated with PM requirement and/or DCM.

Efectividad comparativa del seguimiento remoto a personas con marcapasos cardíacos frente al convencional: calidad de vida a los 6 meses.

BACKGROUND The use of remote follow-up (RF) of people with pacemakers (PM) is limited in comparison to the hospital modality (HS), being still poor the scientific evidence that shows their comparative effectiveness. The aim of this study was to compare the quality of life in individuals with different modalities of follow-up. METHODS Controlled, not randomized nor masked clinical trial, with data collection at pre and post-implantation of pacemakers during the 6 months follow-up. All patients over 18 years-old who were implanted a PM during the study period were selected (n = 83), and they were assigned to RF (n = 30) or HF (n = 53) groups according to their personal characteristics and patient's preferences. Baseline characteristics and number of visits to the hospital were analysed, the EuroQol-5D (EQ5D) questionnaire was administered to evaluate the health-related quality of life, and Duke Activity Status Index (DASI) to assess the functional capacity. RESULTS There were no significant differences between both groups in relation to the baseline analysis, EQ5D (RF:0.7299; HF:0.6769) and DASI (RF:21.41; HF:19.99). At 6 months the quality of life was improved in both groups (EQ5D RF:0.8613; HF:0.8175; p = 0,439) still without significant differences between them. DASI score was similar to baseline (20.51 vs 21.80). RF group performed less transmissions/visits per patient (1.57) than hospital group (1.96; relative reduction 31%; p = 0.015). CONCLUSIONS Remote follow-up of people with pacemakers might be considered as an equivalent option to the hospital follow-up in relation to the quality of life and it reduces the number of hospital visits.

Pacing redistributes glycogen within the developing myocardium.

Electrical pacing at physiological rate induces myocardial remodeling associated with regional changes in workload, blood flow and oxygen consumption. However, to what extent energy-producing pathways are also modified within the paced heart remains to be investigated. Pacing could particularly affect glycogen metabolism since hypertrophy stimulates glycolysis and increased workload favors glucose over fat oxidation. In order to test this hypothesis, we used the embryonic chick heart model in which ventricular pacing rapidly resulted in thinning of the ventricle wall and thickening of the atrial wall. Hearts of stage 22HH chick embryos were submitted in ovo to asynchronous and intermittent ventricular pacing delivered at physiological rate during 24 h. The resulting alterations of glycogen content were determined in atrium, ventricle and conotruncus of paced and sham-operated hearts. Hemodynamic parameters of the paced and spontaneously beating hearts were derived from computerized image analysis of video recordings. With respect to sham, paced hearts showed a significant decrease in glycogen content (nmoles glucose units/microg protein; mean+/-S.D.) only in atrium (1.48+/-0.40 v 0.84+/-0.34, n=8) and conotruncus (0.75+/-0.28 v 0.42+/-0.23, n=8). Pacing decreased the end diastolic and stroke volumes by 34 and 44%, respectively. Thus, the rapid glycogen depletion in regions remote from the stimulation site appears to be associated with regional changes in workload and remodeling. These findings underscore the importance of the coupling mechanisms between metabolic pathways and myocardial remodeling in the ectopically paced heart.

Propagation velocity kinetics and repolarization alternans in a free-behaving sheep model of pacing-induced atrial fibrillation.

AIMS: Experimental models have reported conflicting results regarding the role of dispersion of repolarization in promoting atrial fibrillation (AF). Repolarization alternans, a beat-to-beat alternation in action potential duration, enhances dispersion of repolarization when propagation velocity is involved. METHODS AND RESULTS: In this work, original electrophysiological parameters were analysed to study AF susceptibility in a chronic sheep model of pacing-induced AF. Two pacemakers were implanted, each with a single right atrial lead. Right atrial depolarization and repolarization waves were documented at 2-week intervals. A significant and gradual decrease in the propagation velocity at all pacing rates and in the right atrial effective refractory period (ERP) was observed during the weeks of burst pacing before sustained AF developed when compared with baseline conditions. Right atrial repolarization alternans was observed, but because of the development of 2/1 atrioventricular block with far-field ventricular interference, its threshold could not be precisely measured. Non-sustained AF was not observed at baseline, but appeared during the electrical remodelling in association with a decrease in both ERP and propagation velocity. CONCLUSION: We report here on the feasibility of measuring ERP, atrial repolarization alternans, and propagation velocity kinetics and their potential in predicting susceptibility to AF in a free-behaving model of pacing-induced AF using the standard pacemaker technology.

Bacterial colonization and infection of electrophysiological cardiac devices detected with sonication and swab culture.

BACKGROUND: Electrophysiological cardiac devices are increasingly used. The frequency of subclinical infection is unknown. We investigated all explanted devices using sonication, a method for detection of microbial biofilms on foreign bodies. METHODS AND RESULTS: Consecutive patients in whom cardiac pacemakers and implantable cardioverter/defibrillators were removed at our institution between October 2007 and December 2008 were prospectively included. Devices (generator and/or leads) were aseptically removed and sonicated, and the resulting sonication fluid was cultured. In parallel, conventional swabs of the generator pouch were performed. A total of 121 removed devices (68 pacemakers, 53 implantable cardioverter/defibrillators) were included. The reasons for removal were insufficient battery charge (n=102), device upgrading (n=9), device dysfunction (n=4), or infection (n=6). In 115 episodes (95%) without clinical evidence of infection, 44 (38%) grew bacteria in sonication fluid, including Propionibacterium acnes (n=27), coagulase-negative staphylococci (n=11), Gram-positive anaerobe cocci (n=3), Gram-positive anaerobe rods (n=1), Gram-negative rods (n=1), and mixed bacteria (n=1). In 21 of 44 sonication-positive episodes, bacterial counts were significant (>or=10 colony-forming units/mL of sonication fluid). In 26 sterilized controls, sonication cultures remained negative in 25 cases (96%). In 112 cases without clinical infection, conventional swab cultures were performed: 30 cultures (27%) were positive, and 18 (60%) were concordant with sonication fluid cultures. Six devices and leads were removed because of infection, growing Staphylococcus aureus, Streptococcus mitis, and coagulase-negative staphylococci in 6 sonication fluid cultures and 4 conventional swab cultures. CONCLUSIONS: Bacteria can colonize cardiac electrophysiological devices without clinical signs of infection.

Cardiologie [Cardiology]

Heart failure and atrial fibrillation are the main problems in general cardiology. Our therapeutic reflections summarize new ideas in the treatment of theses pathologies but we will not forget importance of PCI. All these therapies have proven now the clinical benefit but also reduction in more morbidity and mortality. Cardiac resynchronisation therapy has shown promising results. The art of medicine to develop will be to better identify the patients benefiting from this therapy. Interventional cardiology is focusing on the acute coronary syndrome. Not only rapid intervention but also the stent technology allow significant modification of endothelial tissue reaction and therefore improve the general benefit for the patient.

Estimulación con marcapasos para disminuir recurrencias en pacientes adultos con síncope vasovagal: una revisión sistemática

Introducción: El sincope vasovagal es la principal causa de pérdida transitoria de la consciencia. Las guías internacionales de tratamiento del síncope recomiendan con un nivel de evidencia débil, el implante de marcapasos para pacientes refractarios al tratamiento médico que tienen respuesta cardioinhibitoria. Hasta el momento no existe una revisión sistemática que resuma la mejor evidencia disponible a la fecha sobre la estimulación con marcapasos en síncope vasovagal para disminuir recurrencias. Métodos: Revisión sistemática de la literatura de ensayos clínicos aleatorizados acerca del uso del marcapasos en síncope vasovagal para disminuir recurrencias. Resultados: La búsqueda inicial arrojó un total de 299 resultados, de los cuales solo 8 cumplieron los criterios de selección. Se evaluó la recurrencia de síncopes en el grupo de estimulación con marcapasos comparada con el grupo sin estimulación. Con diferencias metodológicas marcadas en los estudios seleccionados en general no hay una evidencia sólida para asegurar que el marcapasos disminuye recurrencias de síncope vasovagal. Discusión: El marcapasos en síncope vasovagal no tiene efecto benéfico en disminución de recurrencias cuando se implanta a toda la población refractaria al tratamiento médico para disminuir recurrencias. Solamente un grupo con características clínicas muy seleccionadas podría beneficiarse de la estimulación con marcapasos para disminuir recurrencias de síncope. Conclusión: La evidencia disponible sugiere que el marcapasos no tiene efecto en disminución de recurrencias en todo el grupo de pacientes con síncope vasovagal refractarios a tratamiento médico.

Correlação entre a qualidade de vida, classe funcional e idade em portadores de marca-passo cardíaco

OBJETIVO: Avaliar se existe correlação entre qualidade de vida e classe funcional em pacientes no pós-implante de marca-passo cardíaco, e sua relação com idade. MÉTODOS: Investigados 107 pacientes de ambos os sexos (49,5% do sexo feminino e 50,5% do sexo masculino), tempo médio de implante 6,36º ±2,99 meses e média de idade 69,3º ±12,6 anos. Para avaliação da classe funcional, foi utilizada escala proposta por Goldman e para qualidade de vida, questionário AQUAREL associado ao SF-36. Realizada análise estatística pela correlação de Spearman, com significância de 5%. RESULTADOS: Foram observadas correlações negativas entre qualidade de vida e classe funcional: AQUAREL nos três domínios, desconforto no peito (r=-0,197, P=0,042), dispneia (r=-0,508, P =0,000), arritmia (r=-0,271, P=0,005) e, no SF-36 nos oito domínios. em relação à idade, correlação negativa com Capacidade Funcional do SF-36 (r=-0,338, P=0,000) e não se observou correlação com AQUAREL. Entre idade e classe funcional observou-se correlação positiva (r=0,237, P=0,014). CONCLUSÃO: Neste estudo, encontrou-se correlação negativa entre qualidade de vida e classe funcional, evidenciando nesta amostra que os pacientes pertencentes a melhor classe funcional apresentaram melhor qualidade de vida. Conforme maior idade, pior a qualidade de vida em Capacidade Funcional e em classe funcional. Sugere-se, que idade e classe funcional influenciam qualidade de vida e as escalas de classificação funcional podem constituir um dos instrumentos que integram a avaliação e refletem a qualidade de vida em portadores de marca-passo.

Avaliação de aspectos da qualidade de vida em pacientes pós-implante de marca-passo cardíaco

Objetivo: Avaliar aspectos da qualidade de vida em pacientes pós-implante de marca-passo e relacionar com gênero, idade e tempo de implante. Métodos: Foram estudados 107 indivíduos de ambos os gêneros (49,5% do sexo feminino e 50,5% do sexo masculino), tempo de implante três a 12 meses (média de 6,36±2,99 meses), estáveis clinicamente com idade acima de 18 anos (média de 69,3±12,6 anos). A avaliação constou de: dados pessoais, clínicos, do implante e questionários de qualidade de vida (AQUAREL e SF-36). Análise estatística empregou teste t e correlação de Pearson, com significância de 5%. Resultados: No SF-36, o menor escore ocorreu no domínio aspectos físicos e o maior, em aspectos sociais. No AQUAREL, o menor escore foi em dispneia e o maior em desconforto. Verificou-se associação significante entre gênero e qualidade de vida no SF-36 (capacidade funcional e aspectos emocionais) e no AQUAREL (dispneia). Observaram-se correlações negativas entre idade e qualidade de vida (capacidade funcional do SF-36 e em desconforto do AQUAREL) em relação ao tempo de implante, correlação com vitalidade do SF-36. Conclusão: Menores escores de qualidade de vida foram encontrados em aspectos físicos e dispneia; maiores em aspectos sociais e desconforto. Homens apresentaram maiores escores de qualidade de vida em capacidade funcional, aspectos emocionais e dispneia. Conforme aumenta a idade, pior é a qualidade de vida em capacidade funcional e desconforto, e, quanto maior o tempo de implante de marca-passo, pior a qualidade de vida em vitalidade. Gênero, idade e tempo de implante influenciam na qualidade de vida, dessa forma, essas variáveis devem ser consideradas nas estratégias para melhora da qualidade de vida em portadores de marca-passo.

Electric Ventilation: indications for and technical aspects of diaphragm pacing stimulation surgical implantation

Objective: Patients with high cervical spinal cord injury are usually dependent on mechanical ventilation support, which, albeit life saving, is associated with complications and decreased life expectancy because of respiratory infections. Diaphragm pacing stimulation (DPS), sometimes referred to as electric ventilation, induces inhalation by stimulating the inspiratory muscles. Our objective was to highlight the indications for and some aspects of the surgical technique employed in the laparoscopic insertion of the DPS electrodes, as well as to describe five cases of tetraplegic patients submitted to the technique. Methods: Patient selection involved transcutaneous phrenic nerve studies in order to determine whether the phrenic nerves were preserved. The surgical approach was traditional laparoscopy, with four ports. The initial step was electrical mapping in order to locate the "motor points" (the points at which stimulation would cause maximal contraction of the diaphragm). If the diaphragm mapping was successful, four electrodes were implanted into the abdominal surface of the diaphragm, two on each side, to stimulate the branches of the phrenic nerve. Results: Of the five patients, three could breathe using DPS alone for more than 24 h, one could do so for more than 6 h, and one could not do so at all. Conclusions: Although a longer follow-up period is needed in order to reach definitive conclusions, the initial results have been promising. At this writing, most of our patients have been able to remain ventilator-free for long periods of time.

Diaphragmatic pacing stimulation in spinal cord injury: anesthetic and perioperative management

OBJECTIVE: The standard therapy for patients with high-level spinal cord injury is long-term mechanical ventilation through a tracheostomy. However, in some cases, this approach results in death or disability. The aim of this study is to highlight the anesthetics and perioperative aspects of patients undergoing insertion of a diaphragmatic pacemaker. METHODS: Five patients with quadriplegia following high cervical traumatic spinal cord injury and ventilator-dependent chronic respiratory failure were implanted with a laparoscopic diaphragmatic pacemaker after preoperative assessments of their phrenic nerve function and diaphragm contractility through transcutaneous nerve stimulation. ClinicalTrials.gov:NCT01385384. RESULTS: The diaphragmatic pacemaker placement was successful in all of the patients. Two patients presented with capnothorax during the perioperative period, which resolved without consequences. After six months, three patients achieved continuous use of the diaphragm pacing system, and one patient could be removed from mechanical ventilation for more than 4 hours per day. CONCLUSIONS: The implantation of a diaphragmatic phrenic system is a new and safe technique with potential to improve the quality of life of patients who are dependent on mechanical ventilation because of spinal cord injuries. Appropriate indication and adequate perioperative care are fundamental to achieving better results.

Ventilação elétrica: indicações e aspectos técnicos do implante cirúrgico do marca-passo de estimulação diafragmática

OBJETIVO: Pacientes com lesão medular cervical alta em geral são dependentes de ventilação mecânica, que, embora salve vidas, está associada a complicações e redução da expectativa de vida devido a infecções respiratórias. A estimulação do diafragma por marca-passo, às vezes chamada de ventilação elétrica, induz a inspiração por estimulação dos músculos inspiratórios. Nosso objetivo foi destacar as indicações e alguns aspectos da técnica cirúrgica empregada no implante laparoscópico dos eletrodos, assim como descrever cinco casos de pacientes tetraplégicos submetidos à técnica. MÉTODOS: A seleção dos pacientes envolveu estudos de condução do nervo frênico por via transcutânea para determinar se os nervos estavam preservados. A abordagem cirúrgica foi laparoscopia clássica, com quatro trocartes. A técnica foi iniciada com o mapeamento elétrico para encontrar os "pontos motores" (pontos de contração máxima do diafragma). Se o mapeamento era bem-sucedido, dois eletrodos eram implantados na face abdominal de cada lado do diafragma para estimular ramos do nervo frênico. RESULTADOS: Dos cinco pacientes, três e um, respectivamente, eram capazes de respirar somente com o uso do marca-passo por períodos superiores a 24 e 6 h, enquanto um não era capaz. CONCLUSÕES: Embora seja necessário um acompanhamento mais longo para chegar a conclusões definitivas, os resultados iniciais são promissores, pois, no momento, a maioria dos nossos pacientes pode permanecer sem ventilação mecânica por longos períodos de tempo.

Potential environmental effects of 765-kV transmission lines : views before the New York State Public Service Commission, cases 26529 and 26559, 1976-1978 /

Contract no. DE-AM-03-76SF0015.

Concepção e teste de eléctrodos para pacemaker de estimulação diafragmática

Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica