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Biomedical subjects

Alberto Alonso-Fernández

Publications and source records attributed to Alberto Alonso-Fernández.

13 recordsLinked to original sources
PubMed2006

Pulmonary hypertension in obstructive sleep apnoea: effects of continuous positive airway pressure: a randomized, controlled cross-over study.

AIMS: We tested the hypothesis that: (i) obstructive sleep apnoea (OSA) by itself originates pulmonary hypertension (PH); and (ii) the application of continuous positive airway pressure (CPAP) can reduce pulmonary pressure. METHODS AND RESULTS: In this randomized and cross-over trial, 23 middle-aged OSA (apnoea-hypopnoea index, 44.1 +/- 29.3 h(-1)) and otherwise healthy patients and 10 control subjects were included. OSA patients randomly received either sham or effective CPAP for 12 weeks. Echocardiographic parameters, blood pressure recordings, and urinary catecholamine levels were obtained at baseline and after both treatment modalities. At baseline, OSA patients had higher pulmonary artery systolic pressure than control subjects (29.8 +/- 8.8 vs. 23.4 +/- 4.1 mmHg, respectively, P = 0.036). Ten out of 23 patients [43%, (95% CI: 23-64%)] and none of the control subjects had PH at baseline (P = 0.012). Two patients were removed from the study because of inadequate CPAP compliance. Effective CPAP induced a significant reduction in the values for pulmonary systolic pressure (from 28.9 +/- 8.6 to 24.0 +/- 5.8 mmHg, P < 0.0001). The reduction was greatest in patients with either PH or left ventricular diastolic dysfunction at baseline. CONCLUSION: Severe OSA is independently associated with PH in direct relationship with disease severity and presence of diastolic dysfunction. Application of CPAP reduces pulmonary systolic pressure levels.

Blood Pressure↗
PubMed2005

Obstructive sleep apnea in atrial fibrillation patients.

A high prevalence of obstructive sleep apnea has been demonstrated in patients with atrial fibrillation. Our comments want to emphasize the importance of identifying and treating a large proportion of patients with atrial fibrillation who have undiagnosed obstructive sleep apnea as an additional preventive strategy for atrial fibrillation patients.

Atrial Fibrillation↗
PubMed2005

Obstructive sleep apnoea-hypoapnoea syndrome reversibly depresses cardiac response to exercise.

AIMS: To evaluate cardiac response to exercise in middle-aged normotensive obstructive sleep apnoea-hypoapnoea syndrome (OSAHS) adults with normal resting left ventricular systolic function and to test the hypothesis that nasal continuous positive airway pressure (CPAP) therapy might improve cardiac performance during exercise. METHODS AND RESULTS: We performed a prospective, randomized, double-blind, placebo-controlled, cross-over clinical trial including 31 consecutive newly diagnosed OSAHS patients and 15 healthy subjects. Cardiopulmonary exercise testing with cardiac output measurement, blood pressure (BP) recordings, and urinary excretion of catecholamine levels were obtained at baseline and after 3 months on both effective and sham CPAP. OSAHS subjects had higher systolic and mean nocturnal BP and higher nocturnal levels of catecholamines. In contrast, they had lower increments in cardiac output (Qt) and in stroke volume (SV) in response to exercise than control subjects. CPAP therapy was associated with highly significant improvements in all the indices of left ventricular systolic performance response during exercise, whereas with sham CPAP, all of them remained unchanged. CONCLUSION: OSAHS patients with normal resting left ventricular systolic function and no hypertension had a worse cardiac response to exercise than healthy subjects. In these patients, 3 months of CPAP improved both Qt and SV responses to exercise.

Analysis of Variance↗
PubMed2005

Obstructive sleep apnea syndrome affects left ventricular diastolic function: effects of nasal continuous positive airway pressure in men.

BACKGROUND: The purpose of this study was to determine the role of obstructive sleep apnea syndrome (OSAS) as an independent risk factor for the development of left ventricular diastolic abnormalities. Moreover, we tested the hypothesis that nasal continuous positive airway pressure (nCPAP) improves such alterations in OSAS patients by eliminating apneic events. METHODS AND RESULTS: In this prospective, randomized, placebo-controlled, double-blind crossover study, 27 consecutive newly diagnosed middle-aged OSAS men with neither controllable factors nor conditions affecting left ventricular diastolic function and 15 healthy control subjects were selected. OSAS patients were randomized to 12 weeks on sham nCPAP and 12 weeks on effective nCPAP application. Echocardiographic parameters, blood pressure recordings, and urinary catecholamine levels were obtained at baseline and after both treatment modalities. At baseline, an abnormal left ventricular filling pattern was present in 15 of the 27 OSAS patients and only in 3 of the 15 control subjects (P=0.020). Impaired relaxation was by far the most common abnormal pattern in both groups (11 and 3 patients, respectively). In OSAS patients, 12 weeks on effective nCPAP induced a significant increase in E/A ratio (P<0.01), as well as reductions in mitral deceleration (P<0.01) and isovolumic relaxation (P<0.05) times. CONCLUSIONS: OSAS can affect left ventricular diastolic function independently of other possible factors. Chronic application of nCPAP could avoid the progression of diastolic abnormalities, and indeed, it might reverse these alterations, at least in the initial stages before severe structural changes can be developed.

Adult↗
PubMed2005

Cardiac rhythm disturbances and ST-segment depression episodes in patients with obstructive sleep apnea-hypopnea syndrome and its mechanisms.

STUDY OBJECTIVES: To compare the frequency of daytime and nocturnal cardiac arrhythmias and ST-segment depression episodes among patients with obstructive sleep apnea-hypopnea syndrome (OSAHS), snoring subjects, and healthy subjects, and to analyze the relationship between the cardiac disturbances, sleep characteristics, and sympathetic tone in patients with OSAHS. PATIENTS AND INTERVENTIONS: Twenty-one consecutive patients with OSAHS, 12 snorers without hypersomnolence, and 15 healthy subjects were selected. Polysomnography, 24-h Holter ECG recording, and urinary catecholamine determination were simultaneously performed on all subjects. RESULTS: Patients with OSAHS had more daytime and nocturnal episodes of sinus and supraventricular arrhythmias and couplets than the snoring and control groups. Moreover, nocturnal ST-segment depression episodes were more frequent in the OSAHS group than in control subjects (0.565 +/- 0.826/h vs 0 +/- 0/h [mean +/- SD]). In patients with OSAHS, arousal index and daytime epinephrine levels were related to daytime and nocturnal ST-segment depression episodes, whereas minimum arterial oxygen saturation was related to nocturnal sinus bradycardia and supraventricular tachycardia. Epinephrine and norepinephrine urinary concentrations correlated with sinus and supraventricular arrhythmias. CONCLUSIONS: Patients with OSAHS have a higher frequency of cardiac rhythm disturbances and ST-segment depression episodes than snoring and control subjects. Moreover, ST-segment changes are related to sympathetic tone and sleep fragmentation, whereas most of the rhythm disturbances in patients with OSAHS are associated with sleep fragmentation, nocturnal hypoxemia, and sympathetic tone.

Arousal↗