Abbott Laboratories Co. is bringing back the megadeal like it’s 2015.

On Thursday, the Abbott Park, Illinois-based health care products manufacturer agreed to buy St. Paul, Minnesota-based St. Jude Medical Inc. in a $25 billion cash-and-stock deal. The transaction, expected to close in the fourth quarter of this year, is aimed at growing the would-be acquirer’s existing cardiovascular offerings and will also see Abbott assume or refinance $5.7 billion of St. Jude’s debt.