Continuous monitoring of sleep-disordered breathing with pacemakers: Indexes for risk stratification of atrial fibrillation and risk of stroke

Background Sleep apnea (SA) is a risk factor for atrial fibrillation (AF). Advanced pacemakers are now able to calculate indexes of SA severity. Hypothesis We investigated the changes in pacemaker-measured indexes of SA, we assessed their predictive value for AF occurrence and the associated risk of stroke and death at long-term. Methods We enrolled 439 recipients of a pacemaker endowed with an algorithm for the calculation of a Respiratory Disturbance Index (RDI). The RDI variability was measured over the first 12 months after implantation, as well as its potential association with the occurrence of AF, defined as device-detected cumulative AF burden >= 6 hoursours in a day. Results The individual RDI mean was 30 +/- 18 episodes/h, and the RDI maximum was 59 +/- 21 episodes/h. RDI >= 30 episodes/h was detected in 351 (80%) patients during at least one night. The proportion of nights with RDI >= 30 episodes/h was 14% (2%-36%). AF >= 6 hours was detected in 129 (29%) patients during the first 12 months. The risk of AF was higher in patients with RDI maximum >= 63 episodes/h (HR:1.74; 95%CI: 1.22-2.48; P = .001) and with RDI mean >= 46 episodes/h (HR:1.63; 95%CI: 1.03-2.57; P = .014). The risk of all-cause death or stroke was higher in patients with AF burden >= 6 hours (HR:1.75; 95%CI: 1.06-2.86; P = .016). Moreover, among patients with no previous history of AF the risk was higher in those with RDI maximum >= 63 episodes/h (HR:1.96; 95%CI: 1.06-3.63; P = .031). Conclusions Pacemaker-detected SA showed a considerable variability during follow-up. We confirmed the association between RDI and higher risk of AF, and we observed an association between higher RDI maximum and all-cause death or stroke among patients with no previous history of AF.