Chemoreflex Control of Sympathetic Activity in Patients With Coronary Artery Disease

Effect of Exercise Training on Chemoreflex Control of Sympathetic Activity in Patients With Coronary Artery Disease and Obstructive Sleep Apnea

The investigators hypothesize that chemoreflex response of muscle sympathetic nerve activity (MSNA) during hypoxia and hypercapnia will be increased in coronary artery disease (CAD) patients and that the presence of obstructive sleep apnea (OSA) will potentiate these responses. And, that the exercise training would decrease the chemoreflex response of MSNA in these patients.

Forty patients with coronary artery disease, with (n=20) and without (n=20) obstructive sleep apnea will be studied. A healthy control, age-paired group (n=10) will be also evaluated. The patients will be submitted to a polysomnography and randomized for clinical follow-up or exercise training for four months. It will evaluated the autonomic function, chemoreflex control of sympathetic activity during hypoxic and hypercapnic maneuvers, endothelial function and inflammatory markers.

Inclusion Criteria:

• Diagnosis of stable coronary artery disease; Age between 35-60 years, male and female; BMI <30 kg/m2 Not involved in a regular exercise program at least three months before the survey;

Exclusion Criteria:

• Patients with angina and / or ischemia,
• Patients with diabetic neuropathy and / or ischemia of the lower limbs;
• Previous diagnosis of chronic pulmonary, neurological and orthopedic diseases, neoplasia, renal failure and insulin-dependent diabetes mellitus;
• Patients with acute myocardial infarction, cardiac surgery or hospitalization of cardiac origin six months before the study and carriers of pacemaker / implantable defibrillator;
• Patients with cardiac dysfunction (ejection fraction of left ventricle <40%);
• Current smoking and pregnant women.