32Development of new-onset atrial tachyarrhythmia and risk of stroke in the implantable cardiac device population

Background: Atrial tachyarrhythmias (ATA) are associated with increased risk of stroke. Implantable cardiac devices (ICDs) can detect and store these arrhythmias. This study investigated the role of stroke risk stratification tools, CHADS2 and CHA2DS2-VASc, in predicting new-onset ATAs in the ICD population. Methods: Retrospective-observational cohort study. Baseline CHADS2 and CHA2DS2-VASc scores were calculated for 158 patients (mean (SD) age 74 (13) years; 63% male) implanted with a cardiac device, between January 2006-December 2009, with no documented ATAs pre-implant. Incidence of device-detected ATAs was recorded within 1-year and >1-year post-implant. Results: During follow up, 50 (31.6%) developed ATAs; 21 (13.3%) within first year. Median (IQR) CHADS2 and CHA2DS2-VASc scores were 2 (2) and 4(2), respectively; no difference in median CHADS2 & CHA2DS2-VASc scores between those who developed ATA and those who did not (p=0.45 and p=0.60, respectively). Cox regression demonstrated that none of the individual stroke risk factors or overall CHADS2 scores [HR (95% CI) 1.13 (0.80-1.46); p 0.33] predicted ATA development, however the CHA2DS2-VASc score appeared to approach significance [HR 1.16 (1.01-1.35); p 0.056]. The overall median time to ATA onset was 337 days. In patients with a CHA2DS2-VASc score=4,5,6 or 7, median time to ATA onset occurred earlier (222, 334, 107 & 94 days, respectively) compared to those with a CHA2DS2-VASc score of 2 or 3 (429 & 951 days, respectively) (Figure). Conclusions: All ICD patients with a CHA2DS2-VASc score ≥ 2 should be followed-up more frequently to identify ATA development and offered effective stroke prevention with oral anticoagulation, where appropriate. ![Graphic][1] Figure Event-free survival from atrial-tachyarrhythmia according to CHA2DS2-VASc score at baseline [1]: /embed/inline-graphic-1.gif