Country singer-songwriter June Carter Cash [ tickets ], the wife of Johnny Cash [ tickets ], was in critical condition on Saturday (5/10) after suffering complications during heart surgery, the couple's manager said in a statement.

According to Lou Robin, Cash underwent surgery on Wednesday (5/7) at a Nashville hospital to replace a heart valve.

Johnny Cash asked for fans to pray for his wife's recovery at 10 a.m. Central Time on Sunday (5/11).

"June did this for him one time when he was critically ill," Robin said in a statement. "The recovery the next morning was something the doctors couldn't describe or imagine."

June Carter, while a member of the influential country group the Carter Family, co-wrote with Merle Kilgare Johnny Cash's hit "Ring of Fire," which rose to No. 1 in 1963. She is credited in biographies with helping Cash to rediscover religion and overcome his drug problems. Carter and Cash married in 1968.

In 1999, June Carter Cash released "Press On," which was her first solo album in more than 25 years.

Johnny Cash was hospitalized at Baptist Hospital in Nashville for most of March for treatment of pneumonia.