What is Cheyne-Stokes breathing and its significance?

Cheyne-Stokes Breathing: Definition and Clinical Significance

Cheyne-Stokes breathing is a specific form of periodic breathing characterized by a crescendo-decrescendo pattern of respiration alternating with periods of central apneas or hypopneas, which is an important marker of severe heart failure and is associated with increased mortality and morbidity. 1

Definition and Diagnostic Criteria

• Cheyne-Stokes breathing (CSB) is characterized by episodes of at least 3 consecutive central apneas and/or central hypopneas separated by a crescendo-decrescendo change in breathing amplitude with a cycle length of at least 40 seconds (typically 45-90 seconds) 1
• For formal diagnosis, there must be 5 or more central apneas and/or central hypopneas per hour associated with this crescendo-decrescendo breathing pattern recorded over a minimum of 2 hours of monitoring 1
• The cycle length is defined as the time from the beginning of a central apnea to the end of the subsequent crescendo-decrescendo respiratory phase 1

Physiological Mechanisms

• CSB occurs primarily during light sleep and is under chemical control, often associated with respiratory alkalosis (low carbon dioxide levels and high pH) 2
• The cycle length of CSB varies with the severity of heart failure - patients with more severe left ventricular dysfunction (lower ejection fraction) typically have longer cycle lengths 1
• In heart failure patients, cycle lengths typically range from 45-90 seconds, compared to shorter cycle lengths (<45 seconds) in other forms of central sleep apnea 1, 3
• CSB appears to be a compensatory mechanism that may improve breathing efficiency and reduce respiratory muscle fatigue in heart failure patients 2

Clinical Significance

• CSB is an important marker of heart failure severity and is associated with increased mortality and morbidity in patients with heart failure 4, 5
• A central apnea-hypopnea index (AHI) >30/hour in heart failure patients with CSB is a poor prognostic sign for survival 1
• Longer duration of CSB is associated with higher mortality and elevated NT-proBNP (a marker of poor cardiac function) 1
• CSB can occur during both sleep and daytime, with daytime CSB present in about 16% of severe heart failure patients and associated with even worse prognosis 6
• CSB may also be observed in patients recovering from acute cardiogenic pulmonary edema, though its presence in this specific setting does not necessarily indicate poor immediate prognosis 7

Clinical Associations

• CSB is most commonly associated with heart failure but can also occur with other conditions including: 3
  • Neurological disorders such as stroke
  • Atrial fibrillation
  • Pulmonary hypertension
  • Renal failure
• CSB may reflect unrecognized congestive heart failure and is a risk factor for early mortality or the need for heart transplant in patients with known heart failure 1

Management Implications

• The presence of CSB should prompt thorough evaluation and optimization of heart failure management 2, 8
• The American Academy of Sleep Medicine recommends focusing on optimizing guideline-based heart failure therapy as the primary intervention 2
• CSB often improves with effective treatment of the underlying heart failure 2, 5
• The duration of CSB (absolute or as a percentage of total sleep time) or the number of CSB events should be specified in sleep study reports 1

Important Caveats

• Interventions specifically aimed at suppressing CSB breathing pattern should be approached with caution, as CSB may be a compensatory mechanism in heart failure 2
• Adaptive servo-ventilation, designed to suppress CSB, has been associated with increased mortality in heart failure patients with reduced ejection fraction 2
• CSB should be distinguished from other forms of periodic breathing that may have different clinical implications and management approaches 1, 3