Annual atrial tachyarrhythmia burden determined by device interrogation in patients with cardiac implanted electronic devices is associated with a risk of ischaemic stroke independent of known risk factors

OBJECTIVES: This study evaluated the risk of non-fatal ischaemic stroke associated with increased long-term cumulative duration of atrial tachycardia (AT). METHODS: We retrospectively reviewed the records of 260 patients with cardiovascular implantable electronic devices capable of monitoring AT. Patients were separated into zero, low and high AT burden groups. The cut-off point between low and high AT burden was defined by the median value of AT burden in the non-zero AT burden groups (5% in 1 year, about 18 days annually). The primary outcome was non-fatal ischaemic stroke. RESULTS: The mean patient age was 63.3 ± 13.7 years, the average follow-up was 7.0 years and 10 patients had strokes. Multivariate analysis showed only hypertension and a diagnosis of atrial fibrillation (AF) were associated with stroke. The risk of stroke in patients with hypertension was 12.57-fold higher than in those without hypertension, and was 20.81-fold higher in patients with paroxysmal AF and 162.59-fold higher in patients with chronic AF than in those without AF. Kaplan-Meier analysis showed that stroke-free survival was significantly different in the three AT burden groups (P = 0.002, long-rank test); the rate was greatest in the zero AT burden group, followed by the low AT burden group and was lowest in the high AT burden group. CONCLUSIONS: Patients who accumulated an AT duration exceeding 5% (18 days) of the total time in any of the 1-year periods are more likely to have an ischaemic stroke than those who have a low or zero AT burden.