Johnson & Johnson's halt of U.S. sales of a new heart-rhythm device due to safety concerns is hobbling a major strategic push by the company into one of the industry's fastest-growing markets. The healthcare company paused use of the device, known as Varipulse, last month after receiving reports of neurovascular events in several patients. The company didn't explain what the events were, but several strokes have been reported to a federal device-safety database, and doctors' concerns are centered on strokes. J&J has been racing to catch up to competitors in the fast-growing market for medical devices treating irregular heart rhythms, and to revive the company's medical-device business generally.
