Abstract 16987: Diurnal Distribution of Cerebrovascular Events in Patients with Atrial Fibrillation on Long Term Warfarin
Background: A diurnal variation in the onset of cardiac events and stroke is well established. There is little data on the diurnal variation of stroke onset in patients with Atrial Fibrillation (AF). Also, the effect of long-term anti-coagulation on time of onset of stroke has not been studied in this population. We analyzed the circadian pattern of strokes in patients with AF on long-term warfarin therapy.
Methods: Patients with AF on warfarin therapy were evaluated for occurrence of ischemic strokes (CVA) and transient ischemic attacks (TIA) between Jan 2010 and Sept 2011. Baseline characteristics including age, sex, CHADS2 score, INR at presentation and the time of onset of events were recorded. We also collected mortality data to check for association between time of event onset and death.
Results: 62 patients with AF on warfarin experienced events over the study period. 44 patients with CVAs and 18 patients had TIAs. 4 patients with unknown time of onset of symptoms were excluded from the analysis. Demographic characteristics and INR of the population are shown in Table 1. The circadian distribution of stroke onset is depicted in Figure 1. There was no clear association between time of stroke onset and mortality.
Conclusion: Strokes in patients with AF on systemic warfarin therapy demonstrate a peak occurrence between 18-24 hours. This pattern is different compared to the pattern described in other clinical syndromes caused by plaque rupture. The nadir point of systemically anti-coagulated state during the evening hours might explain the above distribution.
- © 2012 by American Heart Association, Inc.