WASHINGTON —  Sen. John Warner's office says the Virginian has left a hospital and returned to work after doctors successfully treated his irregular heartbeat with new medications and rhythm treatments for atrial fibrillation.

The 81-year-old Republican was admitted to a Washington-area hospital Monday after a return of the irregular heart rate that first afflicted him last fall. He does not plan to seek a sixth term in November.

Meanwhile, another Senate veteran, Democrat Robert Byrd of West Virginia, remained in a hospital Tuesday following a fall at his home on Monday. Byrd, 90, is the longest-serving senator in history.