[Update on the prevention of thromboembolic phenomena in atrial fibrillation]. / Avances en la prevención de eventos tromboembólicos en pacientes con fibrilación auricular.

Atrial fibrillation is the most common sustained arrhythmia in clinical practice and is associated to thromboembolic complications. Anticoagulation with vitamin K antagonists is clearly useful to reduce the incidence of emboli, but associated with important limitations. Therefore, there is an active search for medications that are more effective and simpler to prescribe and manage. Synthetic pentasaccharides of heparin such as idraparinux for parenteral use, showed promising results. Direct inhibitors of thrombin were also useful for the prevention of thromboembolism. However, they were withdrawn from the market due to potentially fatal adverse reactions. Other area of investigation has been the effectiveness of the combination of antiplatelet agents such as aspirin and clopidrogel. Although this combination is attractive, results of clinical trials must be awaited to have an opinion about its real usefulness. Finally, left atrial appendage transcatheter occlusion (PLAATO) is an effective and reasonably safe method for patients with contraindications for anticoagulation or those that continue to embolize despite well prescribed anticoagulation. The long term results of this intervention must also be awaited.

Avances en la prevención de eventos tromboembólicos en pacientes con fibrilación auricular / Update on the prevention of thromboembolic phenomena in atrial fibrillation

Atrial fibrillation is the most common sustained arrhythmia in clinical practice and is associated to thromboembolic complications. Anticoagulation with vitamin K antagonists is clearly useful to reduce the incidence of emboli, but associated with important limitations. Therefore, there is an active search for medications that are more effective and simpler to prescribe and manage. Synthetic pentasaccharides of heparin such as idraparinux for parenteral use, showed promising results. Direct inhibitors of thrombin were also useful for the prevention of thromboembolism. However, they were withdrawn from the market due to potentially fatal adverse reactions. Other area of investigation has been the effectiveness of the combination of antiplatelet agents such as aspirin and clopidrogel. Although this combination is attractive, results of clinical trials must be awaited to have an opinion about its real usefulness. Finally, ieft atrial appendage transcatheter occlusion (PLAATO) is an effective and reasonably safe method for patients with contraindications for anticoagulation or those that continue to embolize despite well prescribed anticoagulation. The long term results of this intervention must also be awaited.

Survival and growth of Palaemonetes argentinus (Decapoda; Caridea) exposed to insecticides with chlorpyrifos and endosulfan as active element.

Pesticides with chlorpyrifos and endosulfan as active element are used for pest control on agricultural lands and are high-risk inputs in aquatic systems. The acute toxicity of these insecticides in the freshwater prawn Palaemonetes argentinus was evaluated. The results were used to determine the lowest observed-effect and no observed-effect concentrations. Individual growth of prawns in relation to chlorpyrifos and endosulfan exposure was analyzed. LC(50) values to chlorpyrifos and endosulfan exposure were 2.98 microg L(-1) and 14.10 at 24 hours and 0.49 microg L(-1) and 6.28 microg L(-1) at 96 hours of exposure, respectively. The size increment of prawns was the same in all treatments; cephalothorax length increased linearly per molt. The intermolt period was influenced by the toxic effect of pesticides during rearing time, and this decreased with the molt cycles compared with the normal growth pattern. The results suggest that juveniles of P. argentinus are sensitive to chlorpyrifos and endosulfan pollution.

Endocarditis infecciosa: morbimortalidad en Chile: resultados del estudio cooperativo nacional de endocarditis infecciosa, ECNEI, 1998-2002 / Mortality and complications of infective endocarditis in Chile: results of the national cooperative study of infective endocarditis, 1998-2002

Infective endocarditis is a severe condition, with a mortality that fluctuates between 16 and 25 percent in the Metropolitan area of Chile. Aim: To perform a prospective assessment of clinical and microbiological features of patients with infective endocarditis in Chile. Material and methods: Collaborative study of regional hospitals in the whole country and teaching hospitals in Santiago. Patients with a possible or definitive infective endocarditis, according to Duke's criteria, were included in the protocol and a structured data entry form was completed. Results: Three hundred twenty one patients (65 percent male, mean age 49ñ16.5 years) were studied. According Duke's criteria, 89 percent had a definitive and 11 percent a possible endocarditis. The subacute form occurred in 64 percent of patients. The most frequent predisposing cardiopathies were rheumatic in 25 percent, prosthetic valves in 15 percent and congenital in 13 percent. There was no evidence of cardiopathy in 20 percent. Twenty percent of patients were on hemodialysis, 11 percent were diabetic and only one patient abused intravenous drugs. The most frequent complication was cardiac failure in 59 percent of cases, followed by renal failure in 32 percent and embolism in 28 percent. The most frequent causing organism was coagulase positive Staphylococcus in 35 percent. Blood cultures were negative in 28 percent of cases from the metropolitan region, in 56 percent of cases from the north and 38 percent of cases from the south. Echocardiographic diagnosis was done in 92 percent of cases. Aortic valve was involved in 42 percent and mitral valve in 29 percent. Successful antimicrobial treatment was achieved in 59 percent of patients. Thirty five percent of patients were subjected to surgical procedures with a 78 percent survival. Overall mortality was 29 percent. Univariate analysis identified sepsis, an age over 60 years and the presence of cardiac or renal failure as prognostic indicators of mortality. On multivariate analysis, the identified prognostic indicators were the presence of sepsis, renal failure, mitroaortic involvement associated to combined surgery and failure of antimicrobial treatment not associated to surgery. Conclusions: Subacute form is the most common presentation of infective endocarditis and rheumatic valve disease is the most common underlying cardiac lesion. The most frequent causing agent is coagulase positive Staphylococcus...

Muerte súbita por fibrilación ventricular recuperada: ¿síndrome de Brugada? / Sudden death due to ventricular fibrillation: a case of Brugada syndrome?

We report a 47 years old male who was recuperated from a sudden death, and in whom the cardiological assessment showed a right bundle branch block and a fluctuating ST segment elevation from V1 to V3. During the electrophysiological study, a polymorphic tachycardia and a ventricular fibrillation were induced. Procainamide administration enhanced ST segment alterations in right precordial leads, and isoproterenol normalized the EKG. All these disturbances are similar to the condition described by Brugada brothers. The patient was treated with an internal implantable defibrillator, without the use of antiarrhythmic drugs and is well after four months of follow up

Tratamiento anticoagulante en fibrilación auricular: aún no está todo resuelto / Anticoagulation in atrial fibrillation

A great deal of interest has received atrial fibrillation, the most common arrhythmia in adults, due to its complications and difficulttreatment Its most dreaded complication is atrial thrombi formation with the subsequent risk of embolization There are several reports defining risk factors for embolic complications and the usefulness of anticoagulants for their prevention. We review the state of the art of anticoagulation in atrial fibrillation not associated to rheumatic valvulopathy. We also give tools to assess embolic risk and to determine the anticoagulant choice for the different presentation forms of atrial fibrillation

Caries dentaria en Chile y su relación con contenido natural de fluoruros en las aguas de consumo / Dental caries in Chile and its relation to the natural fluoride contents in the drinking waters

Con el propósito de analizar el efecto del contenido natural de fluoruros en la prevalencia de caries, se estudiaron 118 jóvenes (20,2 +- 1,5 años) de dos niveles socioeconómicos que habían nacido y residido en ciudades con distintos niveles de fluoruros (< 0,3 ppm n = 72 y > 0,3 ppm n = 46). En condiciones estandarizadas se midió el COPD y el índice de Grainger que evalúa la severidad del ataque de caries. En ambos grupos el COPD refleja una morbilidad muy alta, pero significativamente mayor en las localidades con menor nivel de fluoruros (11,13 +- 3,53 y 9,82 +- 4,12 p < 0,05). La protección atribuible a los fluoruros fue mayor en el grupo socioeconómico medio-bajo (p<0,05). El padrón de ataque de caries no mostró asociación con el nivel de fluoruros. Se concluye que los fluoruros naturales ejercen una acción protectora, aunque inferior a la descrita en los estudios iniciales sobre el tema