Continuous positive airway pressure (CPAP) improves cardiac function in patients with congestive heart failure (CHF) who also have Cheyne-Stokes respiration and central sleep apnea (CSR-CSA). However, the effects of CPAP in CHF patients without CSR-CSA have not been tested, and the long-term effects of this treatment on clinical cardiovascular outcomes are unknown.
We conducted a randomized, controlled trial in which 66 patients with CHF (29 with and 37 without CSR-CSA) were randomized to either a group that received CPAP nightly or to a control group. Change in left ventricular ejection fraction (LVEF) from baseline to 3 months and the combined mortality-cardiac transplantation rate over the median 2.2-year follow-up period were compared between the CPAP-treated and control groups. For the entire group of patients, CPAP had no significant effect on LVEF, but it was associated with a 60% relative risk reduction (95% confidence interval, 2% to 64%) in mortality-cardiac transplantation rate in patients who complied with CPAP therapy. Stratified analysis of patients with and without CSR-CSA revealed that those with CSR-CSA experienced both a significant improvement in LVEF at 3 months and a relative risk reduction of 81% (95% confidence interval, 26% to 95%) in the mortality-cardiac transplantation rate of those who used CPAP. CPAP had no significant effect on either of these outcomes in patients without CSR-CSA.
CPAP improves cardiac function in CHF patients with CSR-CSA but not in those without it. Although not definitive, our findings also suggest that CPAP can reduce the combined mortality-cardiac transplantation rate in those CHF patients with CSR-CSA who comply with therapy.
"A randomised controlled trial of CPAP for 66 heart failure patients (29 with and 37 without CSA) over a five-year period demonstrated a significantly reduced mortality and cardiac transplantation rate for patients with CSA receiving CPAP. CPAP did not affect mortality or the cardiac transplantation rate in subjects without CSA . These findings were not subsequently replicated in a larger randomised controlled trial in which 258 heart failure patients with CSA were randomly assigned to a CPAP arm or a non-CPAP arm. "
[Show abstract][Hide abstract] ABSTRACT: An abundance of evidence exists in support of primary and secondary prevention for tackling the scourge of cardiovascular disease. Despite our wealth of knowledge, certain deficiencies still remain. One such example is the association between sleep disordered breathing (SDB) and cardiovascular disease. A clear body of evidence exists to link these two disease entities (independent of other factors such as obesity and smoking), yet our awareness of this association and its clinical implication does not match that of other established cardiovascular risk factors. Here, we outline the available evidence linking SDB and cardiovascular disease as well as discussing the potential consequences and management in the cardiovascular disease population.
"Patients with heart failure (HF) frequently have both central sleep apnea (CSA) and obstructive sleep apnea during asleep  . Sleep apnea causes repetitive episodes of hypoxia and arousal from sleep, thereby activating the sympathetic nervous system to result in a predisposition to arrhythmias; thus sleep apnea might comprise an independent risk factor for major cardiac events   . "
[Show abstract][Hide abstract] ABSTRACT: Background: Adaptive servo-ventilation (ASV) can improve ventilatory inefficiency and exercise oscillatory ventilation (EOV) in patients with heart failure (HF) and central sleep apnea (CSA). Although these improvements might originate from both increase in cardiac function and decrease in sympathetic nerve activity, mechanisms underlying the interrelationship remain unknown. Methods: We compared cardiopulmonary exercise test, muscle sympathetic nerve activity (MSNA) and echocardiography findings at baseline and 3.5. ±. 0.8. months (mean. ±. SD) of follow-up in 28 patients with both HF (New York Heart Association functional class II and III; left ventricular ejection fraction (LVEF). <. 45%) and CSA (apnea-hypopnea index (AHI). ≥. 15/h). Of these, 17 patients consented (ASV group) and 11 patients declined (non-ASV group) to undergo ASV treatment. Compliance with ASV and changes in AHI were determined from data collected by integral counters. Results: VE/VCO2-slope and EOV amplitude at baseline were positively correlated with MSNA, but not with LVEF. ASV therapy reduced VE/VCO2-slope and EOV amplitude (both p<0.01) in association with decrease in MSNA (p<0.01) and increase in LVEF (p<0.001). In non-ASV group, however, these parameters remained unchanged. Change in VE/VCO2-slope was correlated with both change in AHI and average use of ASV. By contrast, change in EOV amplitude was correlated with change in AHI. Changes in VE/VCO2-slope and EOV amplitude were correlated with changes of MSNA (p<0.05), but not with those in LVEF. Conclusions: ASV improves ventilatory inefficiency and EOV probably via suppression of CSA and its sympathoinhibitory effect.
IJC Metabolic and Endocrine 12/2013; 1. DOI:10.1016/j.ijcme.2013.11.001
"Directly treating CSB in patients with heart failure is associated with improved cardiac outcomes, but an improvement in survival has not been confirmed (Arzt and Bradley, 2006). The use of continuous positive airway pressure (CPAP) can provide improvements in cardiac function in HF patients with CSB (Arzt et al., 2007), but not in those with normal breathing patterns, or in those patients whose CSB is not eliminated with CPAP (non-responders) (Sin et al., 2000). Further, CPAP responders exhibit considerably improved survival compared to CPAP non-responders (Arzt et al., 2007) and untreated controls; yet there is also the possibility that CPAP responders have a survival advantage based on a less severe ventilatory control instability via a less severe cardiac condition. "
[Show abstract][Hide abstract] ABSTRACT: Control of ventilation dictates various breathing patterns. The respiratory control system consists of a central pattern generator and several feedback mechanisms that act to maintain ventilation at optimal levels. The concept of loop gain has been employed to describe its stability and variability. Synthesizing all interactions under a general model that could account for every behavior has been challenging. Recent insight into the importance of these feedback systems may unveil therapeutic strategies for common ventilatory disturbances. In this review we will address the major mechanisms that have been proposed as mediators of some of the breathing patterns in health and disease that have raised controversies and discussion on ventilatory control over the years.
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