Shahrokh Javaheri, M.D., of the Pulmonary Service in the Department of Veterans Affairs Medical Center and Department of Medicine at the University of Cincinnati College of Medicine in Cincinnati, Ohio, studied 12 male patients with stable heart failure who had more than 15 episodes per hour each night of sleep apnea with breathing pauses during sleep lasting 10 seconds or more.
According to the authors, the 12 patients with stable heart failure were randomized to a double-blind cross-over protocol with either acetazolamide or placebo, taken one hour before bedtime over the course of six nights. There was a two-week washout period between the two study segments with acetazolamide and placebo.
"An important finding of the double-blind study was the significant improvement in patient perception of improved sleep quality, waking up more refreshed, with less daytime fatigue and sleepiness while taking acetazolamide, compared with placebo," said Dr. Javaheri.
The average age of the patients was 66. There were no significant patient differences in body mass index levels, blood pressure or heart rate during the two phases of the study. Each patient underwent a sleep test, an analysis of blood gases as well as a pH study, a measurement of serum electrolytes, a pulmonary function test, plus other measurements at the start of the study and at the completion of each arm.
"We hypothesize that with long-term drug therapy, as sleep-related breathing disorders improve, it may be reflected in an improvement in cardiac function that will further improve periodic breathing, resulting in a positive feedback cycle," said Dr. Javaheri. "Improvement in sleep apnea may assist cardiac function by a variety of mechanisms such as improved oxygenation."
The author points out that since the short-term efficacy of the drug has been documented, more long-term studies are needed to measure patient cardiac function, quality of life and the levels of norepinephrine in the plasma and urine.
MEDICA.de; Source: American Thoracic Society