There are a couple of reasons that might eplain why your insurance company is denying your recent hospitalization. They are either within the rights of the law to do so, or they are not aware of your prior insurance coverage and are imposing pre-eisting condition waiting periods because of this. Any lapse in coverage of more than 60 days can cause waiting periods to apply on your new coverage. According to your listed dates of coverage, if we are reading these correctly, you have had continuous coverage for 10 months. Did you have insurance prior to the coverage that began in August of 2008? The length of time you have had prior coverage (without a 60 day lapse) will be applied to any waiting period. If they pre-eisting condition waiting period on your policy is 1 year, which is common, then the length of prior coverage as of February 2009 was not sufficient to meet the this waiting period. We suspect that this is the reason, but highly suggest you ask your current insurance company for a detailed eplanation. We are a little confused by the timeline, as you mention that you had a treadmill test in May 2009, but your bypass was in February 2009. Do you mean 2008 or earlier for the treadmill test? — June 9, 2009 @ 2:53 pm