Rates of delayed defibrillation after in-hospital cardiac arrest vary widely across US hospitals, according to new research published in the Archives of Internal Medicine.

Researchers analysed data from 200 US hospitals, which included nearly 7,500 patients with in-hospital cardiac arrests between 2000 and 2008.

The study found that delayed defibrillation rates ranged from 2% to 51% and hospital-level factors delayed defibrillation more than patient-level characteristics did.

Researchers said that since defibrillation is associated with improved survival more research was needed to better understand best practices in the delivery of defibrillation at top-performing hospitals.

Delayed defibrillation is defined as more than two minutes from recognition of cardiac arrest to attempted defibrillation.