Biomedical subjects

Alessandra Magini

Publications and source records attributed to Alessandra Magini.

3 recordsLinked to original sources

PubMed2006

Carvedilol reduces exercise-induced hyperventilation: A benefit in normoxia and a problem with hypoxia.

AIMS: To evaluate whether carvedilol influences exercise hyperventilation and the ventilatory response to hypoxia in heart failure (HF). METHODS AND RESULTS: Fifteen HF patients participated to this double blind, randomised, placebo controlled, cross-over study. Patients were evaluated by quality of life questionnaire, echocardiography, pulmonary function and cardiopulmonary exercise tests (ramp and constant workload) both in normoxia (FiO2 = 21%) and hypoxia (FiO2 = 16%, equivalent to a simulated altitude of 2000 m). Carvedilol improved clinical condition and reduced left ventricle size, but had no effect on lung mechanics. In normoxia during exercise, ventilation was lower, V(CO2) unchanged and PaCO2 (constant workload) or PetCO2 (ramp) higher with carvedilol, exercise capacity was unchanged (peak workload 92+/-22 and 90+/-22W for placebo and carvedilol, respectively). Abnormal V(E)/V(CO2) slope was reduced by carvedilol. Hypoxia increased ventilation but less with carvedilol; exercise capacity decreased to 87+/-21W (placebo) and to 80+/-11 W (carvedilol, p < 0.01). With hypoxia, carvedilol decreased V(E)/V(CO2) slope. At constant workload exercise with hypoxia, PaO2 decreased to 69+/-6 mm Hg (placebo) and to 64+/-5 (carvedilol, p < 0.01). CONCLUSION: Carvedilol reduced hyperventilation possibly by reducing peripheral chemoreflex sensitivity as suggested by PaCO2 increase with normoxia and PaO2 decrease with hypoxia without V(CO2) and V(D)/V(T) changes. Lessening hyperventilation is beneficial when breathing normally, but detrimental when hyperventilation is needed for exercise at high altitude.

Adrenergic beta-Antagonists↗

PubMed2005

Exercise capacity in patients with beta-thalassaemia intermedia.

Thalassaemia intermedia patients can suffer fatigue and exercise capacity reduction, possibly because of anaemia, deconditioning and lack of exercise-induced haemoconcentration. We studied 21 beta-thalassaemia intermedia patients, 10 splenectomised (group A) and 11 not splenectomised (group B). Patients were evaluated by cardiopulmonary exercise test with blood sampling for haemoglobin and plasma protein measurements at rest and peak. During exercise, an isolated increase of haemoglobin suggested spleen contraction while a parallel increase of haemoglobin and proteins suggested fluid filtration through capillary wall. Groups were homogeneous for age and gender. Peak oxygen consumption (VO2) was 22.5 +/- 4.4 ml/min/kg (51 +/- 14%) and 24.3 +/- 7.0 (53 +/- 12%) in groups A and B respectively [not significant (NS)]. At rest, haemoglobin was 8.8 g/dl in both groups. Exercise-induced increment was 0.4 +/- 0.2 and 1.0 +/- 0.4 g/dl (P < 0.001) for haemoglobin and 4.0 +/- 3.0 and 5.0 +/- 4.0 g/l (NS) for proteins, in groups A and B respectively. Anaemia was the major cause of peak VO2 reduction (1097 +/- 260 ml/min). However, anaemia did not explain the entire exercise capacity reduction, suggesting the presence of muscular deconditioning. Exercise capacity is reduced in beta-thalassaemia intermedia because of anaemia and muscular deconditioning. Spleen contraction does not significantly influence exercise capacity although exercise-induced haemoconcentration was greater in patients with spleen.

Adult↗

PubMed2004

Spironolactone improves lung diffusion in chronic heart failure.

AIMS: To evaluate whether anti-aldosteronic treatment influences lung diffusion (DLCO) in chronic heart failure (HF) patients. Spironolactone improves clinical conditions and prognosis in chronic HF and reduces connective tissue matrix turnover; DLCO abnormalities in chronic HF are related to increase in fibrosis and connective tissue derangement. METHODS AND RESULTS: Thirty stable chronic HF patients, with reduced DLCO (<80% of predicted), were randomly assigned to active treatment (25 mg spironolactone daily) or placebo in addition to conventional anti-failure treatment. They were evaluated by quality of life questionnaire, laboratory investigations, cardiopulmonary exercise test, and pulmonary function test, which included DLCO and membrane diffusing capacity (DM). The evaluation was done before treatment and 6 months after. Quality of life score and standard pulmonary function tests were not significantly affected by spironolactone, while active treatment increased DLCO due to an increase of DM (DLCO: 18.3+/-3.9 vs. 19.9+/-5.5 mL/min/mmHg; DM: 28.1+/-7.7 vs. 33.3+/-8.6 mL/min/mmHg) and peak oxygen consumption (peak VO2 16.8+/-1.9 vs.18.6+/-2.2 mL/min/kg). Increments of DLCO and peak VO2 were linearly related (R=0.849, P<0.001). CONCLUSION: These data show a positive effect of spironolactone on gas diffusion and exercise capacity suggesting a novel mechanism by which anti-aldosteronic drugs improve HF clinical condition and prognosis.

Exercise Test↗