Medtronic has recalled certain implantable cardioverter defibrillators and cardiac resynchronization therapy defibrillators due to a defect in the manufacturing process that may prevent them from delivering the electrical shock needed to pace a heartbeat or revive a patient in cardiac arrest, the Food and Drug Administration announced yesterday. In an urgent notice to affected customers, the company said to consider replacing implanted devices affected by the recall. Health care professionals may report adverse reactions or quality problems using the devices to FDA’s MedWatch program.