Comparison of benefits and mortality in cardiac resynchronization therapy in patients with atrial fibrillation versus patients in sinus rhythm (Results of the Spanish Atrial Fibrillation and Resynchronization [SPARE] Study).

The efficacy of cardiac resynchronization therapy (CRT) in patients with atrial fibrillation (AF) and the need for atrioventricular junction ablation in these patients is controversial. The aim of the study was to analyze CRT results in patients with permanent AF. A total of 470 consecutive patients who underwent CRT in 6 centers were included in this study. Of these patients, 126 (27%) had permanent AF. Patients were evaluated at baseline and 12 months. No difference was found in the magnitude of improvement experienced by patients with AF compared with those in sinus rhythm (SR) with respect to quality of life, distance in 6-minute walking test, and left ventricular reverse remodeling. Despite the beneficial effects of CRT, death from refractory heart failure at 12 months was higher in patients with AF (17 of 126; 13.5%) than those in SR (14/344; 4.1%; p <0,001). Furthermore, permanent AF was an independent predictive factor for mortality from refractory heart failure (hazard ratio 5.4, 95% confidence interval 1.9 to 15.1). In conclusion, patients with AF treated with CRT who survived at the 12-month follow-up had the same functional improvement and remodeling as those in SR. However, AF was an independent risk factor for mortality from heart failure after CRT implantation.

[Secondary embryonary root associated with seed germination in Garcinia intermedia (Clusiaceae) and its possible role in seedling survival]. / Raíz secundaria embrional asociada a la germinación de Garcinia intermedia (Clusiaceae) y su posible papel en la supervivencia de las plántulas.

Germination tests on Garcinia intermedia (Clusiaceae) seeds showed the growth of two types of roots: additionally to the primary root, a secondary root crosses the seed lengthwise. To determine its possible role on the survival and growth of this species, 90 seedlings at least six months old (collected in Central Costa Rica) were planted in plastic bags with organic soil, and placed in a greenhouse. The seedlings were treated as follows: treatments in which the primary or secondary root was cut off, and a control group with both roots intact (30 replicates each). After three months 10 seedlings/month/treatment were extracted to measure their height, basal diameter, root length (main and secondary root), and biomass of the stem, roots and seed (without its coat). Control seedlings had the highest growth, followed by those without secondary roots. Nonetheless, more than 90% of the seedlings whose primary roots were cut off, survived after five months of the excision treatment, in part due to the capacity of this species to regenerate its radical system through the seed reserves, sprouting of a primary-like root, and/or the growth stimulus of the secondary root (60% of the total: 20% with sprouts from the primary root stump, 13.3% with a growth stimulus of the secondary root, and 26.7% with both conditions). The length of the sprouted roots was significantly different only on those plants that were extracted during the first two monthly measurements, when compared with the control (F6 = 18.6, F7 = 16.0, p < 0.01).

Prevención de la fibrilación auricular en los pacientes con insuficiencia cardiaca / Prevention of atrial fibrillation in patients with heart failure

La insuficiencia cardiaca promueve la aparición de fibrilación auricular y ésta agrava la insuficiencia cardiaca. La fibrilación auricular puede afectar en cualquier momento a un gran porcentaje de los pacientes con insuficiencia cardiaca. La manifestación y presentación clínica cambia con el paso del tiempo y depende de cada paciente. Empeora la sintomatología de los pacientes, como una complicación más de su enfermedad, y causa frustración tanto a los pacientes como a los médicos. Se estima que hasta un 50% de los pacientes con insuficiencia cardiaca presentan fibrilación auricular en algún momento de su evolución, por lo que son necesarias medidas tanto para la prevención de la embolia como para el alivio de los síntomas. La interferencia farmacológica con señales específicas de las vías de transducción es prometedora. Hasta ahora, los agentes más efectivos son los inhibidores de la enzima de conversión de la angiotensina y los antagonistas de los receptores de la angiotensina II, que reducen el estrés oxidativo, restauran las concentraciones de óxido nítrico, inhiben la formación de tejido fibroso y pueden reducir la ectopia de las venas pulmonares. El desenmascaramiento de factores genéticos implicados aún no conocidos puede tener gran repercusión. Es necesario un mejor conocimiento de la fisiología molecular. Esto puede ayudar a desarrollar nuevos regímenes de tratamiento o terapia híbrida con combinación de fármacos «antiarrítmicos» y «no antiarrítmicos» para aumentar la eficacia del tratamiento (AU)

The presence of heart failure increases the risk of atrial fibrillation, a condition which in turn aggravates heart failure. At any point in time, a large percentage of patients with heart failure are affected by atrial fibrillation. Its clinical characteristics change over time and vary according to the individual patient. It worsens patients’ symptoms, adds a further a complication to their illness, and is problematic for both patients and physicians. It is estimated that 50% of patients with heart failure will experience atrial fibrillation, and will require treatment to prevent embolism and relieve symptoms. The ability of drugs to interfere with specific signal transduction pathways is promising. To date, the most effective agents appear to be angiotensin-converting enzyme inhibitors and angiotensin-II receptor antagonists. These compounds reduce oxidative stress, restore the nitric oxide level, inhibit the formation of fibrous tissue, and can ameliorate pulmonary vein ectopy. Uncovering the, as yet unknown, genetic factors involved could have significant implications. Better understanding of the relevant molecular biology is essential. This could lead to new treatment regimes or to hybrid therapy with a combination of antiarrhythmic and non-antiarrhythmic drugs, which could improve treatment effectiveness (AU)