Travis was being treated for viral cardiomyopathy, a heart condition caused by a virus, according to his publicist, Kirt Webster.
The Mayo Clinic's website says the disease weakens and enlarges the heart muscle, making it harder for the heart to pump blood and carry it to the rest of the body. It can lead to heart failure. Treatments range from medications and surgically implanted devices to heart transplants.
The illness is a continuation of a tough run for Travis after a handful of recent high-profile appearances, including a performance during the Country Music Association Festival's nightly concert series and George Jones' funeral.
Long a popular figure in country music, the North Carolina-born singer has been trying to put his life back together after a series of embarrassing public incidents involving alcohol.
Travis pleaded guilty to driving while intoxicated in January following his arrest last year when he was found naked after crashing his Pontiac Trans Am.
Travis was sentenced to two years of probation, fined $2,000 and given a 180-day suspended jail sentence. He was required to spend at least 30 days at an alcohol treatment facility and complete 100 hours of community service.
The multiple Grammy Award-winning singer rode his alternately mellow and majestic voice to stardom in the 1980s and '90s with hits like "Forever and Ever, Amen" and "Three Wooden Crosses."