Cardiopulmonary exercise test predicts sustained ventricular arrhythmias in chronic heart failure.

BACKGROUND: The cardiopulmonary exercise test (CPX) is an affordable tool for risk prediction in patients with chronic heart failure (CHF). We aimed to determine the role of CPX parameters in predicting the risk of incidence of sustained ventricular arrhythmias (SVA) in CHF. METHODS: Sixty-one consecutive patients with CHF enrolled in the Daunia Heart Failure Registry underwent CPX and were followed for 327 ± 247 days. Clinical follow-up was performed every month and anticipated in case of re-hospitalisation for cardiac disease. Incidence of SVA was evaluated by direct clinical examination (ECG, ambulatory ECG). RESULTS: Patients with episodes of SVA (N 14) showed lower values of pVO2 and PetCO2, and higher values of VE/VCO2, VE/VCO2 slope, and VE%. After correction for age, gender, diabetes, ischaemic heart disease and left ventricular ejection fraction, peak VO2 (hazard ratio (HR) 0.68, 95 % confidence interval (CI) 0.51-0.91, p < 0.05), VE% (HR 1.38, 95 % CI 1.04-1.84, p < 0.05), VE/VCO2 (HR 1.38, 95 % CI 1.04-1.82, p < 0.05), VE/VCO2 slope (HR 1.77, 95 % CI 1.31-2.39, p < 0.01), PetCO2 (HR 0.66, 95 % CI 0.50-0.88, p < 0.01) were found as predictors of SVA. At Kaplan-Meier analysis, lower event-free rates were found in subjects with peak VO2 values below median (log rank p < 0.05), values of VE/VCO2 above mean (p < 0.05), higher VE/VCO2 slope tertiles (p <0.05), and values of PetCO2 below median (p < 0.05). CONCLUSIONS: CPX provides prognostic independent information for risk of SVA in subjects with CHF.

PEGylation prevents bacteria-induced platelet activation and biofilm formation in platelet concentrates.

Bacterial contamination of platelet concentrates represents the greatest post-transfusion infectious risk. Biofilm formation in this environment resulting from platelet-bacteria interactions can lead to non-uniform contaminant distribution and thus missed detection. As formation of platelet-bacteria aggregates is largely based on receptor-ligand interactions, we examined whether shielding these events would result in reduced biofilm formation by contaminant bacteria. We introduced methoxypoly(ethylene glycol) to covalently modify the platelet surface using a process termed 'PEGylation'. In the first study of its kind, we demonstrate that PEGylated platelet concentrates inoculated with Staphylococcus epidermidis display a significant reduction in bacterial binding and biofilm formation.

[Prognostic stratification after acute uncomplicated myocardial infarction: exercise test, echo-dobutamine test or both?]. / Stratificazione prognostica dopo infarto miocardico acuto non complicato: test da sforzo, test eco-dobutamina, o entrambi?

OBJECTIVES: The aims of this study were: 1) to assess the relative prognostic value of predischarge dobutamine echocardiography (DE) and exercise electrocardiography (EE) in patients after a first uncomplicated acute myocardial infarction (AMI), and 2) to evaluate the optimal prognostic strategy by using the two tests in different combinations. METHODS: DE (dobutamine infusion 5 to 40 micrograms/kg/min plus atropine 0.25 to 1 mg, if needed) and symptom-limited bicycle EE were performed in 208 patients (mean age 58 +/- 9 years, 90% males), on different days and in random order, 12 +/- 4 days after a first uncomplicated AMI and after pharmacological washout. A stress-induced dyssynergy and ST segment depression > 1 mm were considered criteria of positivity for DE and EE, respectively. Only spontaneous cardiac events were considered: cardiac death, reinfarction (= hard events), and unstable angina requiring hospitalization (= soft events). RESULTS: Thirty-eight events occurred during follow-up (16 +/- 13 months; range: 1-44 months); 5 cardiac deaths, 6 reinfarctions and 27 unstable angina. Patients with a positive DE had a twofold increase in all event rates (26 vs 12%, p < 0.01) and a fourfold increase in the rate of hard events (9 vs 2%, p < 0.05). In contrast, no statistically significant difference was observed in the distribution of the same events between patients with positive and negative EE. Both tests showed similar negative (DE 88%, EE 85%) and positive (DE 26%, EE 24%) predictive values. Among six different strategies (performing either DE or EE only in all patients; EE in all patients; EE in all patients and DE only in those with a positive EE; and DE only in those with a negative EE; EE in all patients and DE only in those with anterior AMI), EE only in patients with inferior or non-Q AMI and DE only in those with anterior AMI), performing DE only in patients with a positive EE gave the highest predictive accuracy-74% (95% confidence intervals 68 to 80) for all events and 77% (95% confidence intervals 71 to 83) for hard events. CONCLUSIONS: In patients with a first uncomplicated AMI, DE is useful in identifying patients at high and low risk of future spontaneous cardiac events. The optimal strategy for prognostication of these patients is to perform EE in all and DE only in the ones with a positive EE.

Prognostic value of dobutamine echocardiography early after uncomplicated acute myocardial infarction: a comparison with exercise electrocardiography.

OBJECTIVES: This study sought to assess the relative prognostic power of dobutamine echocardiography and exercise electrocardiography after acute myocardial infarction. BACKGROUND: The prognostic value of dobutamine echocardiography early after acute myocardial infarction has not yet been reported. METHODS: One hundred seventy-eight patients (mean age 58 +/- 9 years) with a first uncomplicated acute myocardial infarction underwent predischarge dobutamine echocardiography (5 to 40 micrograms/kg body weight per min, plus atropine if needed) and symptom-limited bicycle exercise electrocardiography and were followed up for 17 +/- 13 months. Stress-induced dyssynergy and ST segment depression > 1 mm were considered criteria of positivity for dobutamine echocardiography and exercise electrocardiography, respectively. RESULTS: Dobutamine echocardiography was positive in 83 patients and exercise electrocardiography in 60. At follow-up there were 5 deaths, 6 nonfatal myocardial infarctions (11 hard events) and 20 cases of unstable angina. Dobutamine echocardiography and exercise electrocardiography had similar negative predictive values both for all events (88% and 86%, respectively) and for hard events (98% and 95%, respectively). The hard events rate was significantly higher in patients with positive rather than negative dobutamine echocardiography (relative risk [RR] 5.15, 95% confidence interval [CI] 1.14 to 23.16), although there was no difference between patients with positive and negative exercise electrocardiograms. When Cox analysis was performed, dobutamine echocardiography had an independent prognostic value both for all events (RR 2.88, 95% CI 1.37 to 6.08) and for hard events (RR 6.56, 95% CI 1.42 to 30.46). CONCLUSIONS: After uncomplicated acute myocardial infarction, dobutamine echocardiography and exercise electrocardiography have a similar high negative predictive value for both all events and hard events only. Positive dobutamine echocardiography, but not positive exercise electrocardiography, identifies a group of patients at higher risk of subsequent cardiac events.

Determinación de sulfuro en barros de curtiembre

Teniendo en cuenta que en los barros de curtiembre el sulfuro se encuentra en forma de sulfuros metálicos desplazables con ácido sulfúrico, trata los aspectos sobresalientes del método correspondiente a los sulfuros solubles en ácidos, como se indica en el ensayo EPA. El desarrollo del método considera: principio, conservación de la muestra, equipo para la destilación del sulfuro, preparación de la muestra, reactivos y procedimiento

Determinación de sulfuro en barros de curtiembre

Teniendo en cuenta que en los barros de curtiembre el sulfuro se encuentra en forma de sulfuros metálicos desplazables con ácido sulfúrico, trata los aspectos sobresalientes del método correspondiente a los sulfuros solubles en ácidos, como se indica en el ensayo EPA. El desarrollo del método considera: principio, conservación de la muestra, equipo para la destilación del sulfuro, preparación de la muestra, reactivos y procedimiento