Treatment of Cheyne-Stokes respiration reduces arrhythmic events in chronic heart failure.

OBJECTIVE: This study aimed to investigate whether adequate treatment of Cheyne-Stokes respiration (CSR) reduces the risk of arrhythmic events in patients with chronic heart failure (CHF). METHODS: A cohort of 403 registry patients with CHF (LVEF≤45%, NYHA-class≥2) and implanted cardioverter-defibrillator devices (ICD) was studied. They underwent overnight polygraphy, with 221 having mild or no CSR (apnea-hypopnea index [AHI]<15/h), and 182 having moderate to severe CSR (AHI>15/h). Latter ones were offered therapy with adaptive servoventilation (ASV), which 96 patients accepted and 86 rejected. During follow-up (21± 15 months) defibrillator therapies were recorded in addition to clinical and physiologic measures of heart failure severity. RESULTS: Event-free survival from (a) appropriate cardioverter-defibrillator therapies and (b) appropriately monitored ventricular arrhythmias was shorter in the untreated CSR group compared to the treated CSR and the no CSR group. Stepwise Cox proportional hazard regression analysis showed untreated CSR (a: hazard ratio [HR] 1.99, 95% confidence interval [CI] 1.46-2.72, P < 0.001; b: HR 2.19, 95%CI 1.42-3.37, P < 0.001), but not treated CSR (a: HR 1.06, 95%CI 0.74-1.50; P = 0.77; b: HR 1.21, 95%CI 0.75-1.93, P = 0.43) was an independent risk factor. The treated CSR group showed improvements in cardiac function and respiratory stability compared to the untreated CSR group. CONCLUSION: This study demonstrates a decrease of appropriate defibrillator therapies by ASV treated CSR in patients with CHF and ICD. A reduced exposure to hyperventilation, hypoxia, and improvement in indices of CHF severity and neurohumoral disarrangements are potential causative mechanisms.

Hypotensive effects of positive airway pressure ventilation in heart failure patients with sleep-disordered breathing.

INTRODUCTION: Obstructive sleep apnoea (OSA) as well as central sleep apnoea (CSA) are highly prevalent in heart failure (HF) patients. Positive airway pressure (PAP) therapy is usually intended to treat OSA and CSA. The aim of the present study was to investigate immediate hemodynamic effects of PAP therapy in these patients. MATERIALS AND METHODS: In 61 consecutive HF patients (NYHA ≥ II, EF ≤ 45%) with moderate to severe OSA or CSA (AHI ≥ 15/h) blood pressure (BP) and heart rate (HR) response to PAP therapy initiation was investigated during mask fitting with patients being awake and in supine position. While applying an endexspiratory pressure of 5.8 ± 0.9 cm H(2)O, there was a significant decrease in systolic (-8.9 ± 12.1 mmHg, p < 0.001) and diastolic BP (-5.1 ± 9.2 mmHg, p < 0.001) without a change in HR (p = n.s.). RESULTS: At least a transient drop in mean arterial pressure ≤70 mmHg was seen in 10% of these patients. Logistic regression analysis revealed a significant impact of baseline BP on potential BP drops: lower baseline BP was associated with BP drops. CONCLUSION: PAP therapy may cause unexpected hypotension especially in patients with low baseline BP as seen in HF patients treated according to current guidelines. Whether these hypotensive effects sustain, cause any harm to the patients and/or is responsible for non-acceptance or non-adherence of PAP therapy needs to be determined.

Symptoms of sleep apnoea in chronic heart failure--results from a prospective cohort study in 1,500 patients.

BACKGROUND: In patients with chronic heart failure, sleep-disordered breathing (SDB) is a common co-morbidity worsening prognosis. The aim of this study was to investigate whether assessment of specific symptoms can elucidate presence of SDB in these patients. METHODS: A prospective questionnaire scoring investigation on possible symptoms of sleep apnoea (nocturia, fatigue, daytime sleepiness, snoring, nocturnal sweating, witnessed apnoea's, nap) was conducted in 1,506 consecutive patients with stable chronic heart failure (LVEF ≤45%, NYHA ≥2). Afterwards, polysomnography or polygraphy, capillary blood gas analysis, echocardiography, and cardiopulmonary exercise testing were performed. RESULTS: Adjusted for all significant covariates, snoring (p < 0.01) was the only symptom independently associated with OSA, while witnessed apnoeas (p = 0.02) and fatigue (p = 0.03) independently predicted for CSR. As additional parameters, higher BMI (threshold 26.6; p < 0.01) and higher pCO(2) (threshold 37.6 mmHg; p < 0.01) were independently associated with OSA and male gender (p < 0.001) and lower pCO(2) (threshold 35.0 mmHg; p < 0.001) with CSA. Cumulative questionnaire score results did not sufficiently (OSA--sensitivity 0.40, specificity 0.74; CSA--sensitivity 0.57, specificity 0.59) predict SDB. CONCLUSION: Although in chronic heart failure patients with either OSA or CSA specific symptoms are apparent, combining clinical data, demographic data, and capillary blood gas analysis results appears favourable to determine the presence of SDB.

Complex sleep apnoea in congestive heart failure.

BACKGROUND: Sleep disordered breathing is common and of prognostic significance in patients with congestive heart failure (CHF). Complex sleep apnoea (complexSA) is defined as the emergence of central sleep apnoea during continuous positive airway pressure (CPAP) treatment in patients with obstructive sleep apnoea (OSA). This study aims to determine the prevalence and predictors for complexSA in patients with CHF with OSA, and to assess the effects of treatment with adaptive servoventilation. METHODS: 192 patients with CHF (left ventricular ejection fraction (LVEF) ≤45%, New York Heart Association (NYHA) class ≥2) and OSA (apnoea-hypopnoea index (AHI) ≥15) were investigated using echocardiography, cardiopulmonary exercise testing, measurement of hyperoxic, hypercapnic ventilatory response, 6 min walk test and measurement of N-terminal pro-brain natriuretic peptide (NT-proBNP) prior to CPAP introduction. If patients demonstrated complexSA (AHI >15/h with <10% obstructive events) during CPAP titration, adaptive servoventilation was introduced and the investigations were repeated at 3 monthly follow-up visits. RESULTS: ComplexSA developed in 34 patients (18%) during CPAP titration. After adjustment for demographic and cardiac parameters, measures of CO(2) sensitivity (higher hyperoxic, hypercapnic ventilatory response) were independently associated with complexSA. Patients using adaptive servoventilation had improved AHI, NYHA class, NT-proBNP concentration, LVEF, hyperoxic, hypercapnic ventilatory response, oxygen uptake during cardiopulmonary exercise testing and the relationship between minute ventilation and the rate of CO(2) elimination (VE/Vco(2) slope) at last individual follow-up (14±4 months). CONCLUSION: There is a high prevalence of complexSA in patients with OSA and CHF, and those who develop complexSA have evidence of higher respiratory controller gain before application of CPAP. Treatment with adaptive servoventilation effectively suppressed complexSA and had positive effects on cardiac function and respiratory stability.

Cheyne-Stokes respiration and obstructive sleep apnoea are independent risk factors for malignant ventricular arrhythmias requiring appropriate cardioverter-defibrillator therapies in patients with congestive heart failure.

AIMS: The aim of this first large-scale long-term study was to investigate whether obstructive sleep apnoea (OSA) and/or central sleep apnoea (CSA) are associated with an increased risk of malignant cardiac arrhythmias in patients with congestive heart failure (CHF). METHODS AND RESULTS: Of 472 CHF patients who were screened for sleep disordered breathing (SDB) 6 months after implantation of a cardiac resynchronization device with cardioverter-defibrillator, 283 remained untreated [170 with mild or no sleep disordered breathing (mnSDB) and 113 patients declined ventilation therapy] and were included into this study. During follow-up (48 months), data on appropriately monitored ventricular arrhythmias as well as appropriate cardioverter-defibrillator therapies were obtained from 255 of these patients (90.1%). Time period to first monitored ventricular arrhythmias and to first appropriate cardioverter-defibrillator therapy were significantly shorter in patients with either CSA or OSA. Forward stepwise Cox models revealed an independent correlation for CSA and OSA regarding monitored ventricular arrhythmias [apnoea-hypopnoea index (AHI) ≥5 h(-1): CSA HR 2.15, 95% CI 1.40-3.30, P < 0.001; OSA HR 1.69, 95% CI 1.64-1.75, P = 0.001; AHI ≥15 h(-1): CSA HR 2.06, 95% CI 1.40-3.05, P < 0.001; OSA HR 1.69, 95% CI 1.14-2.51, P = 0.02] and appropriate cardioverter-defibrillator therapies (AHI ≥5 h(-1): CSA HR 3.24, 95% CI 1.86-5.64, P < 0.001; OSA HR 2.07, 95% CI 1.14-3.77, P = 0.02; AHI ≥15 h(-1): CSA HR 3.41, 95% CI 2.10-5.54, P < 0.001; OSA HR 2.10, 95% CI 1.17-3.78, P = 0.01). CONCLUSION: In patients with CHF, CSA and OSA are independently associated with an increased risk for ventricular arrhythmias and appropriate cardioverter-defibrillator therapies.

Adaptive servoventilation improves cardiac function and respiratory stability.

Cheyne-Stokes respiration (CSR) in patients with chronic heart failure (CHF) is of major prognostic impact and expresses respiratory instability. Other parameters are daytime pCO2, VE/VCO2-slope during exercise, exertional oscillatory ventilation (EOV), and increased sensitivity of central CO2 receptors. Adaptive servoventilation (ASV) was introduced to specifically treat CSR in CHF. Aim of this study was to investigate ASV effects on CSR, cardiac function, and respiratory stability. A total of 105 patients with CHF (NYHA ≥ II, left ventricular ejection fraction (EF) ≤ 40%) and CSR (apnoea-hypopnoea index ≥ 15/h) met inclusion criteria. According to adherence to ASV treatment (follow-up of 6.7 ± 3.2 months) this group was divided into controls (rejection of ASV treatment or usage <50% of nights possible and/or <4 h/night; n = 59) and ASV (n = 56) adhered patients. In the ASV group, ventilator therapy was able to effectively treat CSR. In contrast to controls, NYHA class, EF, oxygen uptake, 6-min walking distance, and NT-proBNP improved significantly. Moreover, exclusively in these patients pCO2, VE/VCO2-slope during exercise, EOV, and central CO2 receptor sensitivity improved. In CHF patients with CSR, ASV might be able to improve parameters of SDB, cardiac function, and respiratory stability.