Respiratory sleep disorders in patients with congestive heart failure

Abstract

Respiratory sleep disorders (RSD) occur in about 40-50% of patients with symptomatic congestive heart failure (CHF). Obstructive sleep apnea (OSA) is considered a cause of CHF, whereas central sleep apnea (CSA) is considered a response to heart failure, perhaps even compensatory. In the setting of heart failure, continuous positive airway pressure (CPAP) has a definite role in treating OSA with improvements in cardiac parameters expected. However in CSA, CPAP is an adjunctive therapy to other standard therapies directed towards the heart failure (pharmacological, device and surgical options). Whether adaptive servo controlled ventilatory support, a variant of CPAP, is beneficial is yet to be proven. Supplemental oxygen therapy should be used with caution in heart failure, in particular, by avoiding hyperoxia as indicated by SpO2 values >95%.

Keywords: Sleep apnea; congestive heart failure (CHF).

Figure 1

Overnight diagnostic and CPAP implementation polysomnograms in a 71-year-old male with mitral valve prolapse, atrial fibrillation and normal systolic function. The diagnostic study (A) indicates modest central sleep apnoea (AHI, 46 eph; minimum SpO₂, 75%) whilst 72 kg. Soon thereafter a CPAP study was performed in which oxygenation is much improved (minimum SpO₂, 90%), yet AHI is still high (32 eph) due to persistent central apnoeas. He later proceeded to a mitral valve repair and ablation of cardiac accessory conducting pathways with pacemaker insertion. Follow-up polysomnogram (B) without CPAP in sinus rhythm was then normal (AHI <5 events per hour and minimum SpO₂, 92%). This case highlights the difficulty in managing CSA-CSR with CPAP compared with the ease following mitral valve repair and abolition of atrial fibrillation. CPAP, continuous positive airway pressure; AHI, apnea hypopnea index; CSA-CSR, central sleep apnoea with cheyne stokes respiration.

Figure 2

This 5-min polysomnogram montage showing classic cyclic central sleep apnoea with accompanying cyclic rise and fall in heart rate. Note minimal hypoxemia and cycle length ~50 s.

Figure 3

These two 4-min polysomnogram montages indicate (A) CHF pattern with CSA-CSR and a long apnoea-hyperpnoea cycle length pattern (B) non-CHF (i.e., idiopathic) pattern of CSA with short apnea hypopnea cycle length in patients with normal cardiac function. Cycle lengths greater than 45 s helps distinguish heart failure from non-heart failure patterns. CHF, congestive heart failure; CSA-CSR, central sleep apnoea with cheyne stokes respiration.

Figure 4

High resolution CT scan of the chest indicating absence of emphysema or interstitial lung disease despite a reduced TLCO.

Figure 5

Graphic display of cardiopulmonary exercise test. Note elevated VE/VO₂ slope (indicative of hyperventilation) and absence of hypoxemia with exercise.

Figure 6

Overnight diagnostic and CPAP implementation polysomnograms: diagnostic (A) side and CPAP titration on (B) in 68-year-old male with ischemic cardiomyopathy (note improved oxygenation with CPAP). CPAP, continuous positive airway pressure.

Figure 7

A 5-min diagnostic polysomnogram montage illustrating classic long cycle length CSA-CSR, snoring at peak of ventilation and absence of hypoxemia. CSA-CSR, central sleep apnoea with cheyne stokes respiration.

Figure 8

A 5-min CPAP implementation polysomnogram montage illustrating immediate response to CPAP with marked reduction of CSA-CSR. CPAP, continuous positive airway pressure; CSA-CSR, central sleep apnoea with cheyne stokes respiration.