Context Although left atrial radiofrequency ablation (RFA) is increasingly used for the treatment of chronic atrial fibrillation during mitral valve surgery, its efficacy to restore sinus rhythm and any resulting benefits have not been examined in the context of an adequately powered randomized trial. Objective To determine whether intraoperative RFA of the left atrium increases the long-term restoration of sinus rhythm and improves exercise capacity. Design, Setting, and Patients Randomized, double-blind trial performed in a single UK tertiary referral center with enrollment between December 2001 and November 2003. A total of 101 patients referred for mitral valve surgery with at least 6 months' history of uninterrupted atrial fibrillation were assessed for eligibility; 97 were enrolled. Patients were followed up for 12 months. Intervention Patients were randomly assigned to undergo mitral valve surgery and RFA of the left atrium (n=49) or mitral valve surgery alone (controls; n=48). Main Outcome Measures The primary outcome measure was presence of sinus rhythm at 12 months; secondary measures were patient functional status and exercise capacity (assessed by shuttle-walk test), left atrial contractility, and left atrial and left ventricular dimension and function and plasma levels of B-type natriuretic peptide. Results At 12 months, sinus rhythm was present in 20 (44.4%) of 45 RFA patients and in 2 (4.5%) of 44 controls (rate ratio, 9.8; 95% CI, 2.4-86.3; PϽ.001). Restoration of sinus rhythm in the RFA group was accompanied by a greater improvement in mean (SD) shuttle-walk distance compared with controls (ϩ94 [102] m vs ϩ48 [82] m; P=.003) and a greater reduction in the plasma level of B-type natriuretic peptide (−104 [87] fmol/mL vs −51 [82] fmol/mL; P=.03). Patients randomized to receive RFA had similar rates of postoperative complications and deaths as control patients. Conclusions Radiofrequency ablation of the left atrium during mitral valve surgery for continuous atrial fibrillation significantly increases the rate of sinus rhythm restoration 1 year postoperatively, improving patient exercise capacity. On the basis of its efficacy and safety, routine use of RFA of the left atrium during mitral valve surgery may be justified. Trial Registration ClinicalTrials.gov Identifier: NCT00238706.

BackgroundThe first wave of pandemic influenza A(H1N1)2009 (pH1N1) reached New South Wales (NSW), Australia in May 2009, and led to high rates of influenza-related hospital admission of infants and young to middle-aged adults, but no increase in influenza-related or all-cause mortality.Methodology/Principal FindingsTo assess the population rate of pH1N1 infection in NSW residents, pH1N1-specific haemagglutination inhibition (HI) antibody prevalence was measured in specimens collected opportunistically before (2007–2008; 474 specimens) and after (August–September 2009; 1247 specimens) the 2009 winter, and before the introduction of the pH1N1 monovalent vaccine. Age- and geographically-weighted population changes in seroprevalence were calculated. HI antibodies against four recent seasonal influenza A viruses were measured to assess cross-reactions. Pre- and post-pandemic pH1N1 seroprevalences were 12.8%, and 28.4%, respectively, with an estimated overall infection rate of 15.6%. pH1N1 antibody prevalence increased significantly - 20.6% overall - in people born since 1944 (26.9% in those born between 1975 and 1997) but not in those born in or before 1944. People born before 1925 had a significantly higher pH1N1 seroprevalence than any other age-group, and against any seasonal influenza A virus. Sydney residents had a significantly greater change in prevalence of antibodies against pH1N1 than other NSW residents (19.3% vs 9.6%).Conclusions/SignificanceBased on increases in the pH1N1 antibody prevalence before and after the first pandemic wave, 16% of NSW residents were infected by pH1N1 in 2009; the highest infection rates (27%) were among adolescents and young adults. Past exposure to the antigenically similar influenza A/H1N1(1918) is the likely basis for a very high prevalence (49%) of prepandemic cross-reacting pH1N1 antibody and sparing from pH1N1 infection among people over 85 years. Unless pre-season vaccine uptake is high, there are likely to be at least moderate rates including some life-threatening cases of pH1N1 infection among young people during subsequent winters.

Objectives This meta-analysis sought to determine whether surgical ablation improves clinical outcomes and resource utilization compared with no ablation in adult patients with persistent and permanent atrial fibrillation (AF) undergoing cardiac surgery. Methods A comprehensive search was undertaken to identify all randomized (RCT) and nonrandomized (non-RCT) controlled trials of surgical ablation versus no ablation in patients with AF undergoing cardiac surgery up to April 2009. The primary outcome was sinus rhythm. Secondary outcomes included survival and any other reported clinically relevant outcome or indicator of resource utilization. Odds ratios (OR) and weighted mean differences (WMD) and their 95% confidence intervals (95% CI) were analyzed as appropriate using the random effects model. Heterogeneity was measured using the I2 statistic. Meta-regression was performed to explore the relationship between the benefit from surgical AF and duration of follow-up. Results Thirty-three studies met the inclusion criteria (10 RCTs and 23 non-RCTs) for a total of 4647 patients. The number of patients in sinus rhythm was significantly improved at discharge in the surgical AF ablation group versus (68.6%) the surgery alone group (23.0%) in RCTs (OR 10.1, 95% CI 4.5–22.5) and non-RCTs (OR 7.15, 95% CI 3.42–14.95). This effect on sinus rhythm (74.6% vs. 18.4%) remained at follow-up of 1 to 5 years (OR 6.7, 95% CI 2.8–15.7 for RCT, and OR 15.5, 95% CI 6.6–36.7 for non-RCT). The risk of all-cause mortality at 30 days was not different between the groups in RCT (OR 1.20, 95% CI 0.52–3.16) or non-RCT studies (OR 0.99, 95% CI 0.52–1.87). In studies reporting all-cause mortality at 1 year or more (up to 5 years), mortality did not differ in RCT studies (OR 1.21, 95% CI 0.59–2.51) but was significantly reduced in non-RCT studies (OR 0.54, 95% CI 0.31–0.96). Stroke incidence was not reduced significantly; however, in meta-regression, the risk of stroke decreased significantly with longer follow-up. Other clinical outcomes were similar between groups. Operation time was significantly increased with surgical AF ablation; however, overall impact on length of stay was variable. Conclusions In patients with persistent or permanent AF who present for cardiac surgery, the addition of surgical AF ablation led to a significantly higher rate of sinus rhythm in RCT and non-RCT studies compared with cardiac surgery alone, and this effect remains robust over the longer term (1–5 years). Although non-RCT studies suggest the possibility of reduced risk of stroke and death, this remains to be proven in prospective RCTs with adequate power and follow-up.

Upper abdominal surgery causes respiratory muscle dysfunction. Multiple factors have been implicated in the occurrence of such dysfunction; however, the role of pain remains unclear. To elucidate the role of pain, we studied 50 patients undergoing elective upper abdominal surgery in a randomized, controlled investigation. Inspiratory and expiratory muscle function were assessed through sniff mouth pressure (Psniff) and maximal expiratory pressure (MEP), respectively. Pain during the pressure maneuvers was assessed with a visual analog scale (VAS). Measurements were made before surgery (Session 1), 24 h after surgery (Session 2), and 1 h later, after intramuscular administration of pethidine (analgesia group) or placebo (placebo group) (Session 3). To evaluate the effect of pain, we used a mixed-effects model with random intercept, having either Psniff or MEP as the dependent variable and both surgical operation and the level of pain as fixed effects. Upper abdominal surgery decreased Psniff in both the analgesia and placebo groups (from 70 +/- 15 to 42 +/- 11 cm H(2)O [p < 0.05] in the analgesia group, and from 69 +/- 15 to 42 +/- 10 cm H(2)O [p < 0.05] in the placebo group). Intramuscular pethidine caused an increase in Psniff to 56 +/- 14 cm H(2)O (p < 0.05), whereas placebo had no effect. Pain increased comparably after upper abdominal surgery in both groups (from 0.3 +/- 0.6 to 4.4 +/- 1.5) [p < 0.05] in the analgesia group and from 0.4 +/- 0.5 to 4.3 +/- 1.5 [p < 0.05] in the placebo group). Intramuscular pethidine decreased pain as measured by VAS score to 2.1 +/- 1.0 (p < 0.05) in the analgesia group, whereas placebo had no effect. Psniff had a statistically significant relationship to pain (p < 0.001). Adjusting for the occurrence of surgical operation did not affect this result. MEP showed the same tendency as Psniff, but the observed changes did not reach statistical significance. We conclude that pain contributes to inspiratory muscle dysfunction after upper abdominal surgery.

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