Lamar Odom's condition has improved in a hugely important way ... his heart is on the mend.
Sources familiar with the situation tell us, tests on Lamar's heart Friday morning revealed his heart function is "much better." Doctors have told Lamar's friends and family this is a good sign of improvement, that a critical organ is responding.
Doctors have asked for "calm" in Lamar's room because they do not want him stimulated .... because non-stimulation promotes healing.
Toward that end, doctors have ordered that virtually no one have access to Lamar's room. We're told Khloe is still by Lamar's bedside.