Is heart rate variability the simple solution to diagnose sleep apnoea?

Abstract

Early in the investigation of obstructive sleep apnoea it was recognised that the events of apnoea and hypopnoea are accompanied by concomitant cyclic variations in heart rate 1. The pattern of brady/tachycardia is closely linked to the time course of apnoeic events. As a consequence, this pattern had been used successfully to detect sleep apnoea in patients with clinical symptoms for sleep apnoea. Dedicated devices were developed over the past 15 yrs to detect sleep apnoea at an early stage of the disease using recordings of heart rate, snoring, oxygen saturation and body position 2. These devices were used successfully to stratify the individual risk of patients suffering from sleep-disordered breathing before they were referred to cardiorespiratory polysomnography. Sleep laboratories have limited capacity for cardiorespiratory polysomnography and are expensive in terms of personal costs due to continuous attendance during the night. The sensitivity and specifity of these simplified four channel-based recording systems had been evaluated in many studies giving results for specific systems. A recent systematic review compiled the results of these studies in a comparative overview 3. The review revealed the value and the limitations of systems with respect to the accepted criteria for the diagnosis of sleep apnoea 4. In conclusion, a satisfactory standardisation of terms and of diagnostic criteria regarding the portable diagnosis of sleep apnoea could not be achieved. In parallel with efforts to define evidence-based criteria for the simplified diagnosis of …