C. Escobar

The role of angiotensin receptor blockers and/or angiotensin converting enzyme inhibitors in the prevention of atrial fibrillation in patients with cardiovascular diseases: meta-analysis of randomized controlled clinical trials

The inhibition of the renin‐angiotensin system has demonstrated both experimental and clinical effects in preventing atrial fibrillation. However, there is still uncertainty about the role of these drugs in clinical practice. The objective of this review has been to assess the effects of angiotensin II type‐1 receptor blockers (ARBs) and/or angiotensin converting enzyme inhibitors (ACEIs) for preventing atrial fibrillation. We searched the Cochrane controlled Trials Register (Cochrane Library Issue 4, 2002), MEDLINE (January 1980 to November 2003), EMBASE (January 1980 to November 2003) and reference list of articles. We also contacted manufacturers and researchers in the field. Selection criteria: We conducted a meta–analysis of all randomized controlled clinical trials that compared ARBs and/or ACEIs with either placebo or conventional therapy in patients with either hypertension, heart failure, ischemic heart disease, or diabetes mellitus. The pooled outcome was the development of new onset atrial fibrillation. Two reviewers independently assessed trial quality and extracted data. In some cases, the study authors were contacted for additional information. Seven trials involving a total of 24,849 patients were included (11,328 randomized to active therapy and 13,521 to control). There was a significant statistical difference in the pooled development of atrial fibrillation between the treatment and control group. (OR, 0.57; 95% CI, 0.39 to 0.82); test for overall effect z = 2.98 P = 0.003). Treatment with ACEIs/ARBs markedly reduces the risk of development or recurrence of atrial fibrillation.

Saline irrigated catheter ablation for pulmonary vein isolation in pigs: An experimental model

Focal AF is amenable to radical cure by RF ablation within the PV. The primary purpose of this study was to compare lesion characteristics for irrigated versus standard ablation using three power settings for PV isolation in pigs. Secondary analyses were the comparisons of ablation time and temperature characteristics, and evaluation of short‐term safety in the pig model. In 20 pigs from 25 to 35 kg in weight, transseptal catheterization was performed and then the ablation catheter was advanced into the PV. RF energy was delivered to the ostium of the PV until its isolation was achieved. The animals were euthanized 1 week after ablation for pathological examination. Electrophysiological isolation of the PV was achieved, although it was difficult to achieve a complete circumferencial lesion in the ostium of the PV. Both of these catheters can produce transmural necrosis, even using 15 W of power. The authors did not see any stenosis of the PV. This might be due to the low energy delivery and the short follow‐up. Pulmonary hemorrhage was present in two animals with 50 W of power, high energy output is dangerous for the ablation of the PV. (PACE 2004; 27:495–501)

Lesiones producidas por la ablación con radiofrecuencia del istmo cavotricuspídeo en un modelo experimental

Introduccion y objetivos El empleo de cateteres con punta de 8 mm o irrigados para la ablacion del aleteo auricular produce lesiones mas anchas y profundas que los estandares, hasta de 10 mm de longitud y profundidad. El dano potencial sobre la valvula tricuspide o la vena cava inferior no se ha evaluado de forma reglada. Pacientes y metodo Se hizo ablacion del istmo cavotricuspideo en 26 animales (cerdos, con un peso de 26-52 kg) con un total de 187 aplicaciones, empleando aleatoriamente cateteres estandar de 4 y 8 mm, y cateteres irrigados, con control de la potencia, la impedancia y la temperatura. Resultados Los cateteres irrigados y de 8 mm produjeron lesiones de mayor tamano. En 7 animales (uno con cateter irrigado, 4 con cateter de 8 mm y 2 con cateter estandar) se dano la valvula tricuspide, la lesion fue severa en 3 casos y moderada, en 4. Los casos con lesion valvular habian recibido mayor potencia (59 ± 27 frente a 51 ± 24 W; p = 0,03) y alcanzado temperaturas mas altas (63 ± 4 frente a 55 ± 11 °C; p Conclusiones El dano valvular durante la ablacion del istmo cavotricuspideo puede ser mas frecuente con el uso de alta energia y con cateteres de 8 mm e irrigados, pero tambien se puede producir con cateteres estandares y energias habituales. Para evitarlo, no se deben hacer aplicaciones en el interior del ventriculo derecho, justo encima de la valvula tricuspide.