Secondary infarction in single or in multiple vascular territories: two different entities following subarachnoid hemorrhage?

The pathogenesis of secondary infarctions (SI) after aneurysmal subarachnoid hemorrhage (SAH) is poorly understood. To assess whether SI in single (SSI) or multiple (MSI) vascular territories represent different disease entities, we compared clinical profiles of patients with these patterns of SI. CT/MRI-examinations of 448 patients were reviewed for new infarctions within 28 days after SAH, and categorized into SSI or MSI. Only patients with adequate follow-up imaging excluding any new infarctions were included for analysis (269 patients). Procedure-related infarctions were excluded. Odds ratios (ORs) with corresponding 95% confidence intervals (CI) were calculated for patients with SSI or MSI versus patients without SI to analyze differences in demographic characteristics, vascular risk factors, disease-related characteristics and treatment modalities. Thirty-six patients had SSI, 53 MSI and 180 no SI. ORs in MSI-patients were >1.5 times higher compared with ORs in SSI-patients for multiple vascular risk factors [MSI:5.4 (2.3–13) versus SSI:1.2 (0.5–2.8)], poor clinical condition on admission [MSI:4.6 (2.4–8.9) versus SSI:2.4 (1.1–5.2)], initial loss of consciousness [MSI:2.6 (1.3–5.3) versus SSI:1.1 (0.5–2.3)] and large amounts of intraventricular blood [MSI:2.9 (1.4–5.8) versus SSI:1.5 (0.7–3.2)]. In multivariate analysis ORs remained higher in MSI for presence of multiple vascular risk factors [MSI:1.9 (1.2–2.9) versus SSI:1.1 (0.8–1.7)] and initial loss of consciousness [MSI:3.0 (1.0–8.9) versus SSI:1.6 (0.6–4.0)]. Our findings suggest that SSI and MSI after SAH are not distinct disease entities. MSI was related to the same characteristics as SSI but to a larger extent, specifically to the presence of multiple vascular risk factors, initial loss of consciousness, larger amounts of intraventricular blood, and poor clinical status on admission

Intravenous magnesium prevents atrial fibrillation after coronary artery bypass grafting: a meta-analysis of 7 double-blind, placebo-controlled, randomized clinical trials

<p>Abstract</p> <p>Background</p> <p>Postoperative atrial fibrillation (POAF) is the most common complication after coronary artery bypass grafting (CABG). The preventive effect of magnesium on POAF is not well known. This meta-analysis was undertaken to assess the efficacy of intravenous magnesium on the prevention of POAF after CABG.</p> <p>Methods</p> <p>Eligible studies were identified from electronic databases (Medline, Embase, and the Cochrane Library). The primary outcome measure was the incidence of POAF. The meta-analysis was performed with the fixed-effect model or random-effect model according to heterogeneity.</p> <p>Results</p> <p>Seven double-blind, placebo-controlled, randomized clinical trials met the inclusion criteria including 1,028 participants. The pooled results showed that intravenous magnesium reduced the incidence of POAF by 36% (RR 0.64; 95% confidence interval (CI) 0.50-0.83; <it>P </it>= 0.001; with no heterogeneity between trials (heterogeneity <it>P </it>= 0.8, <it>I</it>²= 0%)).</p> <p>Conclusions</p> <p>This meta-analysis indicates that intravenous magnesium significantly reduces the incidence of POAF after CABG. This finding encourages the use of intravenous magnesium as an alternative to prevent POAF after CABG. But more high quality randomized clinical trials are still need to confirm the safety.</p

Pharmacologic prophylaxis for atrial fibrillation following cardiac surgery: a systematic review

Atrial Fibrillation (AF) is the most common arrhythmia occurring after cardiac surgery. Its incidence varies depending on type of surgery. Postoperative AF may cause hemodynamic deterioration, predispose to stroke and increase mortality. Effective treatment for prophylaxis of postoperative AF is vital as reduces hospitalization and overall morbidity. Beta - blockers, have been proved to prevent effectively atrial fibrillation following cardiac surgery and should be routinely used if there are no contraindications. Sotalol may be more effective than standard b-blockers for the prevention of AF without causing an excess of side effects. Amiodarone is useful when beta-blocker therapy is not possible or as additional prophylaxis in high risk patients. Other agents such as magnesium, calcium channels blocker or non-antiarrhythmic drugs as glycose-insulin - potassium, non-steroidal anti-inflammatory drugs, corticosteroids, N-acetylcysteine and statins have been studied as alternative treatment for postoperative AF prophylaxis

Hemodynamic effects of synchronized high-frequency jet ventilation compared with low-frequency intermittent positive-pressure ventilation after myocardial revascularization

Background: The purpose of this prospective study was to examine the effect on cardiac performance of selective increases in airway pressure at specific points of the cardiac cycle using synchronized high-frequency jet ventilation (sync-HFJV) delivered concomitantly with each single heart beat compared with controlled mechanical ventilation in 20 hemodynamically stable, deeply sedated patients immediately after coronary artery bypass graft. Methods: Five 30-min sequential ventilation periods were used interspersing controlled mechanical ventilation with sync-HFJV twice to control for time and sequencing effects. Sync-HFJV was applied using a driving pressure, which generated a tidal volume resulting in gas exchanges close to those obtained on controlled mechanical ventilation and associated with the maximal mixed venous oxygen saturation. Hemodynamic variables including cardiac output, mixed venous oxygen saturation and vascular pressures were recorded at the end of each ventilation period. Results: The authors found that in 20 patients, hemodynamic changes induced by controlled mechanical ventilation and by sync-HFJV were similar. Cardiac index did not change (mean ± SD for controlled mechanical ventilation: 2.6 ± 0.7 1 · min-1 · m-2; for sync-HFJV: 2.7 ± 0.7 1 · min-1 · m-2; P value not significant). This observation persisted after stratification according to baseline left- ventricular contractility, as estimated by ejection fraction. Conclusions: The authors conclude that after coronary artery bypass graft, if gas-exchange values are maintained within normal range, sync-HFJV does not result in more favorable hemodynamic support than controlled mechanical ventilation. These findings contrast with the beneficial effects of sync-HFJV, resulting in marked hypocapnia, on cardiac performance observed in patients with terminal left-ventricular failure

Intravenous amiodarone or magnesium sulphate is not cost‐beneficial prophylaxis for atrial fibrillation after coronary artery bypass surgery

Our aims were to examine whether the administration of amiodarone or magnesium sulphate after coronary artery bypass graft surgery (CABG) could reduce the occurrence of atrial fibrillation, and to identify the risk factors associated with atrial fibrillation after CABG. Patients scheduled for elective CABG (n=155) were allocated randomly, in a controlled double‐blind study, to receive immediately after surgery a 72‐h infusion of amiodarone (900mg per 24h), magnesium (4g per 24h) or placebo (0.9% NaCl; 50ml per 24h) intravenously. A 72‐h Holter ECG was recorded concomitantly. The primary end‐point was the prevention of atrial fibrillation; its onset was considered as prophylactic failure. An interim safety analysis was performed in 147 patients. The cumulative occurrence of atrial fibrillation was 27% in the placebo group, 14% in the amiodarone group (P=0.14) and 23% in the magnesium group (P=0.82). Although amiodarone delayed the onset of the first tachyarrhythmic episode (P=0.02), it was associated with the need for longer periods of vasoactive drug infusion and invasive monitoring and a longer stay in the intensive care unit. Variables associated with the onset of atrial fibrillation were older age (odds ratio 1.9) and a plasma magnesium concentration at 24h of less than 0.95 mmol litre-1 (odds ratio 6.7). Postoperative administration of amiodarone reduced the occurrence of atrial fibrillation after elective CABG surgery, but was associated with a longer duration of cardiovascular instability and longer need for intensive care; magnesium prophylaxis had no effect. Advanced age and a low plasma magnesium concentration are risk factors for postoperative atrial fibrillation. Br J Anaesth 2000; 85: 690-