Doctors have said that band vocalist and Filipino music icon Ely Buendia on Sunday is in stable condition following the medical emergency that saw him being rushed to hospital Saturday night at the height of the reunion concert of his former band, the Eraserheads. In a message to ABS-CBN News, record label Sony BMG said Buendia is now "stable" after suffering hypokalemia Saturday night, 15 songs into the band's one-night-only reunion concert at the Fort Bonifacio Open Field. Hypokalemia is a medical condition in which the concentration of potassium in the blood is low. It is brought about by a variety of reasons, including effects from medications and diet patterns. Buendia has been administered with a potassium intravenous fluid and is now recuperating at the Philippine Heart Center in Quezon City. Sony BMG said the administration of the IV hurt him a bit but was tolerable. Day Cabuhat, manager of Buendia's current band Pupil, also told ABS-CBN News that he is already doing fine and is resting. "Ely is doing fine, he is resting now. We just want to let the people know that his condition is stable but he's still under observation. We want to thank the fans and everyone for their concern, support and prayers," Cabuhat said. Buendia experienced chest pains and reportedly collapsed backstage after the first set of the long-awaited reunion concert. He was transferred to the Heart Center around 1 a.m. Sunday after being treated at the Makati Medical Center's emergency room. The singer was brought out of the Makati hospital on a stretcher. Buendia's family has declined to comment on his condition. [b]Fans, friends, react[/b] Meanwhile, Buendia's friend, filmmaker Joyce Bernal, denied that the singer suffered a heart attack. She said Buendia suffered chest pains due to the stress brought about by his mother's recent death and exhaustion due to the rehearsals for the concert. Buendia's mother died of cardiac arrest early morning of August 28. She had been recovering from surgery done just days before to treat her intestinal cancer. MTV Philippines head Francis Lumen, who co-produced the concert, said that Buendia is resting to recover from stress and exhaustion. Buendia's family is requesting the media to refrain from interviews and shooting video of the singer. Bandmembers and Buendia's sister informed the crowd about what happened to the singer, and announced at the concert that the Eraserheads' frontman "is in a lot of physical and emotional stress lately." Despite his mother's death on August 28, the former Eraserheads vocalist decided to push through with the concert, anyway. A witness at the Makati Medical Center emergency room earlier told abs-cbnNEWS.com that Buendia appeared unconscious and was taken to the critical care area late Saturday night. The witness said several doctors rushed to Buendia and a minor commotion ensued. The witness also said that the news going around the ER was that the singer had a heart attack. [b]Health, concert problems[/b] Buendia had a previous heart attack in January 2007. He underwent two angioplasty procedures (a surgical operation where narrowed or blocked arteries are widened) at the Philippine Heart Center after doctors found at least two blockages in his arteries. Doctors said the singer has a history of heart disease in his family and was genetically predisposed to it. The Eraserheads reunion concert became controversial after its first sponsor, cigarette-maker Philip Morris, was accused of violating Philippine laws prohibiting tobacco companies from sponsoring concerts and other promotional events. When Philip Morris pulled out of the production due to legal concerns, it was Lumen who took over the sponsorship of the show. Eraserheads member Raimund Marasigan said Buendia still pushed through in participating in their reunion concert even with the stress he had gone through lately. Marasigan, along with fellow Eraserheads members Buddy Zabala and Marcus Adoro, are still hoping they would all get together onstage soon and perform as the Eraserheads one more time. The Eraserheads, formed in the late 1980s, was the most successful Filipino band of the 1990s, and is widely credited for reviving the Filipino band scene. The band broke up in 2002, but the members of the band are still active in the music scene.