Gian Domenico Pinna1, Elena Robbi2, Michele Terzaghi3, Daniela Corbellini4, Maria Teresa La Rovere4, Roberto Maestri5. 1. Department of Biomedical Engineering, Istituti Clinici Scientifici Maugeri, IRCCS Montescano, Montescano, Italy. Electronic address: giandomenico.pinna@icsmaugeri.it. 2. Sleep Laboratory, Department of Pneumology, Istituti Clinici Scientifici Maugeri, IRCCS Montescano, Montescano, Italy; Department of Cardiology, Istituti Clinici Scientifici Maugeri, IRCCS Montescano, Montescano, Italy. 3. Unit of Sleep Medicine and Epilepsy, IRCCS Mondino Foundation, Pavia, Italy. 4. Department of Cardiology, Istituti Clinici Scientifici Maugeri, IRCCS Montescano, Montescano, Italy. 5. Department of Biomedical Engineering, Istituti Clinici Scientifici Maugeri, IRCCS Montescano, Montescano, Italy.
Abstract
OBJECTIVE: The interplay between arousals and respiratory events during Cheyne-Stokes respiration (CSR) with central sleep apnea (CSA) in heart failure (HF) patients is still not fully understood. We investigated the temporal relationship between arousals and CSR-CSA. METHODS: Episodes of CSR-CSA during sleep stages N1-N2 were analyzed in 22 HF patients with an apnea-hypopnea index ≥15/h, dominant CSA and central apnea index ≥5/h. For each CSR-CSA cycle (apnea + hyperpnea), we determined the onset (ARonset, relative to hyperpnea onset) and duration of detected arousals. RESULTS: Arousals (N = 2348) mostly occurred within the first half of the hyperpneic phase (42.6%, ARonset = 10.6 ± 2.1 s; duration = 10.6 ± 5.2 s) or close to hyperpnea onset (21.5%, ARonset = -0.1 ± 0.6 s; duration = 13.9 ± 5.4 s). Within-apnea arousals were less frequent (12.4%, ARonset = -16.0 ± 4.7 s; duration = 3.8 ± 1.4 s). The proportion of CSR-CSA cycles without any hyperpnea-related arousal was 27.5 ± 18.2%. Hyperpnea-related arousability (total number of hyperpneic arousals/total duration of hyperpneas) and apnea-related arousability were 63.4 ± 21.0/h and 23.8 ± 16.9/h, respectively (p < 0.0001). CONCLUSION: During CSR-CSA, a significant proportion of arousals occur at hyperpnea onset, indicating a low arousal threshold. Hyperpneic arousals are not essential for CSR-CSA. Arousability markedly increases during hyperpneas, likely due to the concurrent increase in chemoreceptor stimulation. SIGNIFICANCE: This study extends current knowledge on the interplay between sleep instability and respiratory events during CSR-CSA.
OBJECTIVE: The interplay between arousals and respiratory events during Cheyne-Stokes respiration (CSR) with central sleep apnea (CSA) in heart failure (HF) patients is still not fully understood. We investigated the temporal relationship between arousals and CSR-CSA. METHODS: Episodes of CSR-CSA during sleep stages N1-N2 were analyzed in 22 HF patients with an apnea-hypopnea index ≥15/h, dominant CSA and central apnea index ≥5/h. For each CSR-CSA cycle (apnea + hyperpnea), we determined the onset (ARonset, relative to hyperpnea onset) and duration of detected arousals. RESULTS: Arousals (N = 2348) mostly occurred within the first half of the hyperpneic phase (42.6%, ARonset = 10.6 ± 2.1 s; duration = 10.6 ± 5.2 s) or close to hyperpnea onset (21.5%, ARonset = -0.1 ± 0.6 s; duration = 13.9 ± 5.4 s). Within-apnea arousals were less frequent (12.4%, ARonset = -16.0 ± 4.7 s; duration = 3.8 ± 1.4 s). The proportion of CSR-CSA cycles without any hyperpnea-related arousal was 27.5 ± 18.2%. Hyperpnea-related arousability (total number of hyperpneic arousals/total duration of hyperpneas) and apnea-related arousability were 63.4 ± 21.0/h and 23.8 ± 16.9/h, respectively (p < 0.0001). CONCLUSION: During CSR-CSA, a significant proportion of arousals occur at hyperpnea onset, indicating a low arousal threshold. Hyperpneic arousals are not essential for CSR-CSA. Arousability markedly increases during hyperpneas, likely due to the concurrent increase in chemoreceptor stimulation. SIGNIFICANCE: This study extends current knowledge on the interplay between sleep instability and respiratory events during CSR-CSA.