Medtronic Net Up on Higher ICD Sales  CHICAGO (Reuters) - Medtronic Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=MDT.N target=/stocks/quickinfo/fullquote"&gt;MDT.N&lt;/A&gt; on Wednesday  said its quarterly earnings rose on surprisingly brisk demand  for devices that slow racing heartbeats, offsetting a  weaker-than-expected performance in some of its other  businesses.