Exercise Training in Chronic Heart Failure: Beneficial Effects on Cardiac

Abnormalities of autonomic nervous function are associated with a poor prognosis of patients with chronic heart failure (CHF). We studied the effects of a 6-mo exercise training pro-gram on Q–T interval dispersion, heart rate and blood pressure variability, baroreflex sensitivity, myocardial blood flow (MBF), and presynaptic sympathetic innervation in 13 patients with New York Heart Association class II–III heart failure. Methods: MBF was measured with the H215O and C15O technique. Cardiac presynaptic innervation was studied by 11C-hydroxyephedrine (HED) retention assessed with PET. Heart rate and blood pres-sure variability and baroreflex sensitivity were tested with the phenylephrine method. All studies were performed before and after a 6-mo exercise training program. The exercise capacity was determined by spiroergometry, and Q–T dispersion was measured from a standard 12-lead electrocardiogram. Results