Table 1

Demographic and clinical data of the study population before introduction of continuous positive airway pressure

OSA (n=158)ComplexSA (n=34)p Value
Male, n (%)134 (79.2)33 (97.1)0.79
Age, years64.8±9.865.6±10.00.72
Ischaemic cause, n (%)92 (0.58)18 (0.53)0.48
CRT device implanted, n (%)93 (0.59)18 (0.53)0.63
Body mass index29.4±5.328.2±4.70.23
NYHA class2.5±0.62.7±0.7<0.01
Heart rate72±1372±160.83
Systolic blood pressure115±23118±200.38
Diastolic blood pressure74±1269±130.02
Atrial fibrillation, n (%)31 (19.6)8 (23.5)0.79
Arterial hypertension, n (%)126 (79.7)26 (76.5)0.84
Diabetes, n (%)47 (29.7)6 (17.6)0.10
Medication, n (%)
β-Blockers143 (90.5)33 (97.1)0.41
ACE/AT1 inhibitors156 (98.7)33 (97.1)0.95
Aldosterone blockers103 (65.2)21 (61.8)0.88
Amiodarone42 (26.6)10 (29.4)0.86
Digitalis glycosides57 (36.1)14 (41.2)0.74
Diuretics151 (95.5)27 (79.4)<0.01
Blood gas analysis and sleep studies
pco2, mm Hg40.3±4.537.0±4.0<0.001
po2, mm Hg75.6±10.077.6±11.60.34
AHI, /h33.1±15.130.4±13.20.32
Mean oxygen saturation (%)91.9±3.192.6±3.00.54
Maximum oxygen desaturation (%)80.5±6.580.7±6.50.89
Average oxygen desaturation (%)5.6±5.25.8±4.00.70
Longest apnoea duration, s38.5±21.335.5±19.30.43
Longest hypopnoea duration, s53.1±27.151.2±22.00.67
LVEF (%)31.6±7.430.1±7.50.31
LVEDD, mm70.0±9.069.5±11.90.21
LAD, mm50.0±8.850.2±7.50.89
Cardiopulmonary exercise testing and six-minute walk
Duration, min7.5±3.07.4±2.40.91
Maximum workload, watts82.5±35.290.6±32.50.25
Vo2-AT, ml/min/kg12.9±3.712.7±3.10.79
Vo2 peak, ml/min/kg14.7±4.114.4±3.90.73
Vo2 predicted, %60.3±18.363.7±17.60.32
VE/Vco2 slope30.5±4.033.7±5.30.001
Six-minute walk test, m379±111382±850.90
Laboratory measurement
NT-proBNP, pg/ml1662±31572789±39400.14
Hb, /ml13.5±2.614.0±1.30.11
Sodium, μg/l137.3±5.9139.6±7.90.41
Creatinine, μg/l1.3±0.51.3±0.40.70
CRP, ng/ml0.8±0.90.8±0.80.92
HCVR, l/min/mm Hg2.52±1.494.60±3.66<0.001
  • ACE/AT1, angiotensin-converting enzyme/angiotensin 1 receptor; AHI, apnoea– hypopnoea index; BE, base excess; CRP, C-reactive protein; CRT, cardiac resynchronisation therapy; ComplexSDA, complex sleep apnoea; Hb, haemoglobin; HCVR, hyperoxic, hypercapnic ventilatory response; LAD, left atrium dimension; LVEDD, left ventricular end-diastolic dimension; LVEF, left ventricular ejection fraction; NT-proBNP, N-terminal pro-brain natriuretic peptide; NYHA, New York Heart Association; OSA, obstructive sleep apnoea; pco2, partial pressure of CO2; po2, partial pressure of O2; sPAP, systolic pulmonary artery pressure; VE/Vco2 slope, the relationship between minute ventilation and the rate of CO2 elimination; Vo2, oxygen consumption; Vo2-AT, oxygen consumption at the individual aerobic–anaerobic threshold.