Cardiac function after CPAP therapy in patients with chronic heart failure and sleep apnea: a multicenter study.

BACKGROUND AND PURPOSE: Continuous positive airway pressure (CPAP) is an effective treatment for sleep apnea (SA), although the evidence for improving chronic heart failure (CHF) is inconclusive. Our aim was to evaluate the effect of CPAP treatment on the left ventricle ejection fraction (LVEF) among other cardiological variables in a randomized, multicenter, placebo (sham-CPAP)-controlled study. METHODS: After the selection procedure, 60 patients with CHF with LVEF<45% and SA with an apnea-hypopnea index (AHI)>10/h were evaluated at baseline, and after 3 months of treatment with optimal CPAP or sham-CPAP. The assessment was based on the LVEF, hypertension, daytime sleepiness (Epworth sleepiness scale [ESS]), quality of life (SF-36), New York Heart Scale (NYHA score), dyspnea (by using the Borg scale) and exercise tolerance (6-min walk test). RESULTS: The mean AHI was normalized in the optimal CPAP group but not in the sham-CPAP group. The LVEF showed a significant improvement in the group of patients treated with CPAP (2.5; 95% CI: 0.6 to 4.3), which was not observed in the sham-CPAP group (0.0; 95% CI: -2.1 to 2.1). However, the change in the LVEF from baseline to 3 months was not significantly greater in the whole group (obstructive and Cheyne-Stokes events) treated with CPAP than in the control group (p: 0.07). In patients with only obstructive sleep apnea (OSA), who account for 83% of the total population, there was a significant improvement in the LVEF in the group of patients treated with CPAP but no such improvement in the sham-CPAP group. In this OSA group, the change in the LVEF from baseline to 3 months was significantly greater in the group treated with CPAP than in the sham-CPAP group (p: 0.03). The other variables studied were not modified. When the patients were divided according to the severity of the LVEF (a LVEF cut-off of 30%), improvement was observed in those with a LVEF>30. No changes were found in the other cardiological variables. CONCLUSIONS: CPAP therapy proved to be useful in patients with associated sleep-disordered breathing and CHF. The improvement was more marked in patients with a LVEF>30%. However, the increased LVEF in the CPAP group was not accompanied by changes in the other cardiological variables.

Oxidative stress and fibrosis in incipient myocardial dysfunction in type 2 diabetic patients.

BACKGROUND: The existence of a diabetic cardiomyopathy has been recently supported by epidemiological studies. Increased oxidative stress and myocardial fibrosis has been hypothesized as etiopathogenic mechanisms. We sought to demonstrate the existence of incipient myocardial dysfunction in type 2 diabetes and its relation with markers of oxidative stress and myocardial fibrosis. METHODS: We studied by echocardiography 25 uncomplicated type 2 diabetic patients and 12 sex- and age-matched control subjects. Stress-corrected endocardial and midwall shortening and systolic and early diastolic velocity of the lateral mitral annulus (Doppler tissue) were used as parameters of myocardial function. Serum levels of glutathione peroxidase and procollagen type I carboxy-terminal peptide were used as markers of oxidative stress and myocardial fibrosis, respectively. RESULTS: Diabetics had significant lower values of corrected endocardial shortening than control subjects (P = 0.029). Both systolic and early diastolic mitral annulus velocities were significantly reduced in diabetics as compared to control subjects (P = 0.008 and P = 0.003, respectively). In diabetic patients, corrected endocardial (r = -0.56) and midwall shortening (r = -0.38) correlated with procollagen type I carboxy-terminal peptide, whereas systolic and early diastolic velocities of the mitral annulus correlated with glutathione peroxidase (both r = 0.44). CONCLUSIONS: In a highly selected group of uncomplicated type 2 diabetic patients, we found evidence of systolic and diastolic myocardial dysfunction, especially with the use of pulsed Doppler tissue imaging. The correlations between parameters of myocardial function and glutathione peroxidase and procollagen type I carboxy-terminal peptide support a mechanistic role for the increased oxidative stress and myocardial fibrosis in the myocardial dysfunction of type 2 diabetes.

Comparison of Doppler echocardiography, color M-mode Doppler, and Doppler tissue imaging for the estimation of pulmonary capillary wedge pressure.

To overcome the limitations of mitral inflow parameters for predicting pulmonary capillary wedge pressure (PCWP), combined indices (with Doppler tissue imaging or color M-mode Doppler) have been developed. This study was aimed to compare the accuracy of these indices to predict PCWP. Sixty-one patients were studied. The best correlations with PCWP were found for indices that combined isovolumic relaxation time with flow propagation velocity (color M-mode) or early diastolic velocity of the lateral mitral annulus (Doppler tissue). Both closely tracked changes in PCWP. The color M-mode-derived index was the most accurate in patients with normal systolic function.