Fan site SickThingsUK reports former Alice Cooper guitarist Steve Hunter is currently in hospital in Phoenix, Arizona with atrial fibrillation (the most common cardiac arrhythmia, or irregular heartbeat).
The doctors have kept him in overnight to allow medication to get his normal heart rhythm back and do tests to discover the cause.
An update to the original story adds that Steve's heart has since reverted to its normal rhythm after 19 hours.
Hunter toured with Cooper throughout 2011, but opted to leave the legendary rocker's touring band in 2012 to concentrate on solo projects.
Alice Cooper posts second weekly audio blog
VIDEO: Alice Cooper rocks Later with Jools Holland
Alice Cooper debuts weekly audio blog
Alice Cooper’s Rock Teen Center grand opening this weekend
Alice Cooper mazes coming to Universal Studios’ Halloween Horror Nights
VIDEO: Alice Cooper throws out first pitch at Detroit Tigers game
VIDEO: Alice Cooper, Steven Tyler, Joe Perry & Johnny Depp rock Dark Shadows premiere party
VIDEO: Alice Cooper rocks with Slash
Alice Cooper: L.A. archives broken into
Alice Cooper receives Doctor Of Music honors
Alice Cooper talks about upcoming Iron Maiden tour
Iron Maiden announce North American tour
VIDEO: Alice Cooper rocks Show Harley event in Montreal
Alice Cooper to drop puck at Phoenix Coyotes game
Alice Cooper live package due next month
VIDEO: Steven Tyler rocks Walk This Way on New Year’s Eve
VIDEO: Steven Tyler rocks Beatles classic with Alice Cooper
Alice Cooper to rock Maui on New Year’s Eve
VIDEO: Alice Cooper hosts UK TV game show
VIDEO: Alice Cooper discusses Welcome 2 My Nightmare
AUDIO: Alice Cooper rocks L.A. club show