The leaders of the U.S. Senate and the House of Representatives are at loggerheads over a 21 percent Medicare reimbursement rate cut that went into effect June 18, stalling a move to stave off the cut for six months.

The impasse between House Speaker Nancy Pelosi (D-Calif.) and Senate Majority Leader Harry Reid (D-Nev.) stems from a June 17 Senate vote to once again delay a mandated rate cut. The House, which is out of session until this evening, was expected to approve the delay once it reconvened. Pelosi dashed cold water on those hopes over the weekend, saying she saw no reason to pass the bill as a separate measure from the jobs bill.

The current imbroglio is the latest, most severe symptom of a financial infection Medicare contracted in 1997, when Congress passed a deficit reduction bill mandating a so-called "sustainable growth rate." Billed as a tweak aimed at saving a few billion dollars, the growth rate formula instead drove sharp cuts to Medicare reimbursement rates, already 25 percent to 35 percent below market rates.

Instead of fixing the formula,Congress passed a series of temporary fixes until the healthcare reform push last year. Democrats’ efforts to correct the problem — estimated to cost $300 billion — were shot down during the extended wrangling over the reform act.

A 10-year freeze to the reimbursement formula, which would forestall further rate cuts, would cost about $276 billion, according to a Congressional Budget Office estimate (PDF).

Doctors were already abandoning Medicare in ever-increasing numbers, even before the largest-ever cut June 18. That’s expected to cost millions after the Centers for Medicare and Medicaid Services waiting weeks to reimburse doctors for an estimated 50 million claims, hoping for another rate cut reprieve. CMS estimates that, at 30 cents each to process, the first wave of claims processing would cost about $15 million if the six-month stay ever sees the light of day, according to Politico.