WASHINGTON (AP) — Sen. John Warner, R-Va., was in a Virginia hospital Tuesday for observation of a heart condition.

Warner, 81, has suffered atrial fibrillation, which can cause an irregular heartbeat, since last fall, his office said. On Monday, he "consulted with the Capitol physician, completed his office appointments and left for a scheduled admission to Inova Fairfax Hospital, where he remains for observation," the office said in a statement Tuesday.

Warner "recently experienced a return of atrial fibrillation" and is "pursuing a re-evaluation and readjustment of medications."