55 rule

55 rule

A clinical guideline used in patients with aortic regurgitation to gauge the timing of surgery, which should be performed when the ejection fraction falls below 55% or before the left ventricle contracts to 55 mm or less.

55 rule

Cardiology A clinical guideline used in Pts with aortic regurgitation to gauge the timing of surgery, which should be performed when the ejection fraction falls below 55%, or before  the left ventricle can no longer contract to the end-systolic dimension is > 55 mm or less. See Aortic regurgitation.
References in periodicals archive ?
Financial watchdogs fined it pounds 750,000 for no fewer than 55 rule breaches.
05 Listowel Irish Stallion Farms EBF Premier Nursery Handicap 1m ATR Card page 55 RULE THE WAVES, who trounced his rivals on his nursery debut at Killarney last month, and Cocoon give Aidan O'Brien two shots at landing this valuable event for the fourth time in five years.
These are the types of kids who can benefit most from his strict yet loving 55 rules, the doctrine he has used to turn laggards into leaders in standardized test results and other measures.
The formal US complaint to the WTO lists 55 rules, laws and policies that it says the Chinese government uses to restrict these raw material exports.