Symptoms of poor functional status during persistent atrial fibrillation (Afib) may be under-reported, a retrospective study in patients with implantable cardiac devices (ICDs) found. Following ICD implantation, the first persistent Afib episode emerged at 980 days and lasted a median of 87 days. When matched to a group with no persistent Afib, patients with persistent Afib held a disadvantage in mortality at 4 years (20.6% versus 8.6%, P<0.01), wrote Mihail G. Chelu, MD, PhD, of University of Utah School of Medicine in Salt Lake City, and colleagues. Daily activity fell after the onset of persistent Afib — from an average of 135 minutes/day at baseline, the 4 consecutive weeks following Afib onset showed decreasing amounts of activity (by 8%, 11%, 14%, and 17%, respectively, P<0.001), they reported in JACC: Clinical Electrophysiology. The study included 266 patients from the Medtronic CareLink database. Patients had dual-chamber ICDs and persistent Afib lasting at least 28 consecutive days. For 85% of patients, physical activity returned to within 10% of baseline within 12 weeks after their persistent Afib ended. Patients whose persistent Afib remained intact, however, never returned to baseline. The authors made their case that bed rest alone can’t account for the dive in physical activity, writing that “it is unlikely that a patient would be hospitalized for an extended period of 4 weeks.” What’s more, that patients lacking relief from persistent Afib did not recover their normal levels of physical activity “is of particular importance as patients with long standing persistent Afib frequently report no or very few symptoms,” they emphasized. “Objective measures of activity may more accurately reflect the impact of persistent Afib on patients’ functional status,” the investigators concluded. Disclosures Chelu disclosed no relevant relationships with industry. Several co-authors disclosed relationships with Medtronic.