Cardiovascular diseases : heart failure, coronary artery disease, arrhythmias, and hypertension

There is a bidirectional relationship between cardiovascular diseases (CVD), sleep disordered breathing and quality of sleep. The repeated exposure to biological consequences of obstructive sleep apnea (OSA) including altered blood gas chemistry, arousals and large negative swings in intrathoracic/juxta-cardiac pressure will in the long run lead to a variety of cardiovascular disorders including hypertension, heart failure, arrhythmias, coronary artery disease and stroke. Randomized controlled trials have consistently demonstrated that treatment of OSA lowers blood pressure, particularly those with resistant hypertension and most adherent to therapy with continuous positive airway pressure (CPAP) devices. However, so far, randomized controlled trials have failed to show that therapy with CPAP improves downstream cardiovascular consequences. Notably, the Achilles tendon of these trials has been the lack of adequate adherence to CPAP. Central sleep apnea (CSA) frequently occurs in subjects with left ventricular dysfunction, particularly those with heart failure and reduced ejection fraction. The acute consequences of CSA are qualitatively similar to OSA, though less severe. Multiple observational trials have shown the efficacy of adaptive servoventilation in suppressing CSA. Yet, unlike OSA, a large randomized controlled trial on cardiovascular outcomes was neutral or even detrimental, showing lack of efficacy of treatment with adaptive servoventilation when compared to usual care. Another trial using an adaptive servoventilation device with an updated algorithm is in progress. This chapter intends to provide a comprehensive overview of the major cardiovascular consequences of sleep disturbances also pointing to research gaps and perspectives. Several observational studies have shown associations between sleep duration or quality and CVD. Yet, prospective data are not available and the observed relationships may be due to confounders