Study objectives: Although sleep disordered breathing is thought to be common in patients with systolic heart failure, prior studies are difficult to interpret due to a variety of factors including small sample sizes, referral bias to sleep laboratories among participants, lack of modern medical therapy for congestive heart failure, and the failure to use modern techniques to assess breathing such as nasal pressure. Our objective was to determine the current prevalence of sleep disordered breathing in a state-of-the-art congestive heart failure clinic.
Methods: We conducted a prospective study of consecutive patients who visited our heart failure clinic to assess the prevalence of sleep apnea in all eligible patients on maximal medical therapy. We used 4-channel recording equipment and modified Chicago criteria for scoring respiratory events (using heart rate response as a surrogate for arousal from sleep).
Results: We observed that among the 108 participants, 61% had some form of sleep disordered breathing (31% central apnea with Cheyne Stokes respiration and 30% obstructive sleep apnea). Sleep disordered breathing was significantly associated with atrial fibrillation (OR = 11.56, p = 0.02) and worse functional heart failure class (OR = 2.77, p = 0.02), after adjusting for male sex, age over 60 years, body mass index, and left ventricular ejection fraction.
Conclusions: We conclude that both obstructive and central sleep apnea remain common in congestive heart failure patients despite advances in medical therapy, and that the previously reported high prevalence values are unlikely to be explained by referral bias or participation bias in prior studies. These data have important clinical implications for practitioners providing CHE therapy.