Predictive value of newly detected atrial fibrillation paroxysms in patients with acute ischemic stroke, for atrial fibrillation after 90 days.

BACKGROUND AND PURPOSE Extended cardiac monitoring immediately after acute ischemic stroke (AIS) increases paroxysmal atrial fibrillation (PAF) detection, but its reliability for detection or exclusion of longer term paroxysmal PAF is unknown. We evaluated the positive and negative predictive value (PPV and NPV) of AF detection early after AIS, for PAF confirmation 90 days later. METHODS We investigated 49 patients within 7 days of AIS for PAF according to current guidelines; 23 patients received 7 days of additional noninvasive cardiac event monitoring with an R-test device early after their stroke (ISRCTN 97412358). Ninety days after AIS, everyone underwent 7 days of cardiac event monitoring. We calculated the PPV and NPV of immediate PAF detection through extended cardiac event monitoring and through any investigative modality, for the presence of PAF on the 90-day event monitor. RESULTS PAF detected by a 7-day event monitor within 2 weeks of AIS had a PPV of 100% (95% confidence interval, 72%-100%) for PAF confirmation after 90 days. NPV after 7 days of event monitoring was 64% (95% confidence interval, 35%-87%). PAF detected early through any modality had a PPV of 100% (95% confidence interval, 76%-100%). However, the NPV in the absence of R-test monitoring was only 42% (95% confidence interval, 28%-58%). CONCLUSIONS AF detection through any means immediately after stroke holds strong PPV for confirmation after 90 days, justifying treatment decisions on early monitoring alone. However, failure to identify AF through early monitoring has only modest NPV even after 7 days of monitoring; repeated investigation is desirable.