Performance of conventional and enhanced adaptive servoventilation (ASV) in heart failure patients with central sleep apnea who have adapted to conventional ASV

Evaluation of the prevalence and nature of sleep-disordered breathing (SDB) in patients with symptomatic chronic heart failure (CHF) receiving therapy according to current guidelines. We prospectively screened 700 patients with CHF (NYHA class> or =II, LV-EF< or =40%) for SDB using cardiorespiratory polygraphy (Embletta). Furthermore, echocardiography, cardiopulmonary exercise and 6-min walk testing were performed. Medication included ACE-inhibitors and/or AT1-receptor blockers in at least 94%, diuretics in 87%, beta-blockers in 85%, digitalis in 61% and spironolactone in 62% of patients. SDB was present in 76% of patients (40% central (CSA), 36% obstructive sleep apnoea (OSA)). CSA patients were more symptomatic (NYHA class 2.9+/-0.5 vs. no SDB 2.57+/-0.5 or OSA 2.57+/-0.5; p<0.05) and had a lower LV-EF (27.4+/-6.6% vs. 29.3+/-2.6%, p<0.05) than OSA patients. Oxygen uptake (VO(2)) was lowest in CSA patients: predicted peak VO(2) 57+/-16% vs. 64+/-18% in OSA and 63+/-17% in no SDB, p<0.05. 6-min walking distances were 331+/-111 m in CSA, 373+/-108 m in OSA and 377+/-118 m in no SDB (p<0.05). This study confirms the high prevalence of SDB, particularly CSA in CHF patients. CSA seems to be a marker of heart failure severity.

Heart failure is a highly prevalent disorder that continues to be associated with repeated hospitalizations, high morbidity, and high mortality. Sleep-related breathing disorders with repetitive episodes of asphyxia may adversely affect heart function. The main aims of this study were to determine the prevalence, consequences, and differences in various sleep-related breathing disorders in ambulatory male patients with stable heart failure. This article reports the results of a prospective study of 81 of 92 eligible patients with heart failure and a left ventricular ejection fraction < 45%. There were 40 patients without (hourly rate of apnea/hypopnea, 4 +/- 4; group 1) and 41 patients with (51% of all patients; hourly rate of apnea/hypopnea, 44 +/- 19; group 2) sleep apnea. Sleep disruption and arterial oxyhemoglobin desaturation were significantly more severe and the prevalence of atrial fibrillation (22% versus 5%) and ventricular arrhythmias were greater in group 2 than in group 1. Forty percent of all patients had central sleep apnea, and 11% had obstructive sleep apnea. The latter patients had significantly greater mean body weight (112 +/- 30 versus 75 +/- 16 kg) and prevalence of habitual snoring (78% versus 28%). However, the hourly rate of episodes of apnea and hypopnea (36 +/- 10 versus 47 +/- 21), episodes of arousal (20 +/- 14 versus 23 +/- 11), and desaturation (lowest saturation, 72 +/- 11% versus 78 +/- 12%) were similar in patients with these different types of apnea. Fifty-one percent of male patients with stable heart failure suffer from sleep-related breathing disorders: 40% from central and 11% from obstructive sleep apnea. Both obstructive and central types of sleep apnea result in sleep disruption and arterial oxyhemoglobin desaturation. Patients with sleep apnea have a high prevalence of atrial fibrillation and ventricular arrhythmias.

Adaptive servo-ventilation (ASV) is a novel method of ventilatory support designed for Cheyne-Stokes respiration (CSR) in heart failure. The aim of our study was to compare the effect of one night of ASV on sleep and breathing with the effect of other treatments. Fourteen subjects with stable cardiac failure and receiving optimal medical treatment were tested untreated and on four treatment nights in random order: nasal oxygen (2 L/min), continuous positive airway pressure (CPAP) (mean 9.25 cm H(2)O), bilevel (mean 13.5/5.2 cm H(2)O), or ASV largely at the default settings (mean pressure 7 to 9 cm H(2)O) during polysomnography. Thermistor apnea + hypopnea index (AHI) declined from 44.5 +/- 3.4/h (SEM) untreated to 28.2 +/- 3.4/h oxygen and 26.8 +/- 4.6/h CPAP (both p < 0.001 versus control), 14.8 +/- 2.3/h bilevel, and 6.3 +/- 0.9/h ASV (p < 0.001 versus bilevel). Effort band AHI behaved similarly. Arousal index decreased from 65.1 +/- 3.9/h untreated to 29.8 +/- 2.8/h oxygen and 29.9 +/- 3.2/h CPAP, to 16.0 +/- 1.3/h bilevel and 14.7 +/- 1.8/h ASV (p < 0.01 versus all except bilevel). There were large increases in slow-wave and rapid eye movement (REM) sleep with ASV but not with oxygen or CPAP. All subjects preferred ASV to CPAP. One night ASV suppresses central sleep apnea and/or CSR (CSA/CSR) in heart failure and improves sleep quality better than CPAP or 2 L/min oxygen.