Clinical significance of pacemaker-detected atrial high-rate episodes

Purpose of review Pacemakers currently being implanted offer several advanced diagnostic features. Among these is the ability to store-counters and intracardiac electrograms of individual atrial high-rate episodes, which are a surrogate of atrial fibrillation. As the majority of these episodes are brief and asymptomatic, their clinical significance remains to be determined. The purpose of this review is to provide a better understanding of the clinical significance of pacemaker-detected atrial high-rate episodes. Recent findings Follow-up after dual-chamber pacemaker implantation demonstrates that nearly 30% of patients without a know n history of atrial fibrillation develop an atrial high-rate episode lasting 5 min or more. Patients experiencing such an episode are at a twofold increased risk of stroke and death. An important risk factor for developing an atrial high-rate episode is a high burden of right ventricular pacing, suggesting that ventricular pacing should be minimized whenever possible. Summary Atrial high-rate episodes are frequently observed in patients after dual-chamber pacemaker implantation and can be associated with adverse outcomes. Ongoing studies seek to determine whether the overall burden of these episodes correlates with the risk of thromboembolism, especially in patients without a history of atrial fibrillation, which would help guide decision-making regarding the initiation of anticoagulation.