It's the first time scientists have demonstrated that a problem at a molecular level can lead to any type of acquired heart failure. Acquired heart failures are the common ones, the researchers say, in contrast to those that are inherited, far rarer forms of the disorder. Stunning exacts a high cost because of the added need for specialized patient care and the worry patients and their families experience with a prolonged recovery. Marked by a general weakness in the heart muscle, the disorder lasts from a few hours to days.
Cardiologists quickly place patients on adrenalin or a similar drug that strengthens heart beat.
Though stunning normally passes, some patients require life support, and some, especially those with complications, die. The conditions that trigger stunning are specific, Murphy says. Adult heart attack victims who've had blood supply restored through drugs or angioplasty also are prone. The scientists also found the shorter TnI in heart muscle samples from patients with weakened hearts. But to see if faulty TnI causes cardiac stunning, Murphy explains, the team cloned genes for abnormal human TnI and inserted them into mice.