[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 However, they were withdrawn from the market due to potentially fatal adverse reactions.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 However, they were withdrawn from the market due to potentially fatal adverse reactions.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.

Desfibrilador implantable en el manejo de taquiarritmias ventriculares malignas: experiencia del Centro Nacional de Arritmias / Implantable defibrillators in the management of malignant ventricular tachyarrhythmias

Background: Implantable defibrillators are the most effective means to prevent sudden death in patients with malignant ventricular tachyarrhythmias. The availability of this type of devices is limited in Chile, due to their high price. Aim: To report the first patients treated with implantable defibrillators in our hospital. Patients and methods: Nine males and one female aged 13 to 65 years old are reported. Three presented with ventricular fibrillation (presenting out of the hospital in three) and the rest had ventricular tachycardia resistant to drugs or radiofrequency ablation. Results: All implantswere performed using intracardiac electrodes. The generator was implanted in the pectoral region in nine and in the abdomen in one. A successful defibrillation was obtained with less than 15 J in four patients, with 20 J in three and with 24 J in three. There were no complications during the procedure. After a 12 months follow up, four patients have been treated by the implantable device. One of these subjects had a ventricular fibrillation in two occasions. One patient died of a bronchopneumonia two years after the implant. Conclusions: Implantable defibrillators are an effective therapy for the treatment of malignant ventricular arrhythmias with a high risk of sudden death

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

Tromboembolismo pulmonar masivo tratado con infusión selectiva de estreptoquinasa: comunicación de 2 casos / Massive pulmonary thromboembolism treated with selective infusion of streptokinase: report of 2 cases

We report 2 patients who developed massive pulmonary embolism with > 50% occludion of the pulmonary arterial circulation. Hypotension, syncope and right sided failure were the clinical manifestations. Immediately after diagnostic pulmonary arteriography, 20,000 U of streptokonase (SK) were delivered in the pulmonary artery nest to the thrombotic mass. A continous infusion of SK, 10,000 U/h was maintained for 24h in one patient and 72h in the other. Rapid clincial improvement was observed in the following 24h. Control angiography showed lysis of the embolus with residual obstructions of segmentary branches. The clinical value of this form of treatment for pulmonary embolism is discussed

Terapía combinada de propranolol y diltiazem en angina crónica de esfuerzo / Combined therapy with propranolol and diltiazem in with chronic exertional angina

The effects of diltiazem, 240 mg/day, were studied in 12 p atients with chronic exertional angina and angiographically proven coronary artery disease, who received maintenance therapy with propranolol. Mean age was 60,1 years (range 46 to 67). Patients received propranolol, 60 to 240 mg/day, before and during the study. A double blind, placebo contorlled, cross-over design was used to test the effect of added diltiazem, durign 8 weeks. Duration fo execise varied from 398 ñ 30 (mean ñ SEM) to 419 ñ 37 (placebo) or 469 ñ 35 sec (diltiazem) (NS). Time to appearance of angina veried from 283 ñ 32 to 313 ñ 34 and 302 - 27 sec, respectively (NS). Resting and maximal effort heart rate and blood pressure did not differ among basal, placebo and iltiazem conditions. Segmental wall motion analysis by radioisotopic ventriculogram revealed diskynetic zones during placebo rodiltiazem therapy. Basal ejection fraction did not increase during exercise and this was not modified by diltiazem or placebo. Thus, the addition of diltiazem to propanolol in patients with chronic, exertional angina failed to modify angina threshold, exercise duration or left ventricular performance