With sales down in key businesses, Medtronic Inc., the world's biggest medical technology company, said on Tuesday that it will eliminate up to 2,000 jobs -- roughly 4% to 5% of its global workforce of 41,000 employees. Officials at Medtronic were unsure just yet how that would affect the company's 8,000 employees in Minnesota. But the company's biggest business -- Mounds View-based Cardiac Rhythm Disease Management --is among its most-troubled. In the third quarter, sales of the unit's heart defibrillators and pacemakers declined 2%, to $1.2 billion. The news comes at a time when a slow economy and uncertainty over the way doctors use some medical devices, how patients pay for them and how regulators approve them weigh heavily on med-tech companies.