NEW : first of seven Jackson girlfriends takes the witness stand Friday . Doctor testifies Murray could n't have been saved even if Dr. Murray had told about propofol . Balloon in Jackson 's heart was `` to prepare Dr. Murray mentally to accept '' his death , doctor says .
NEW : First of three Murray girlfriends takes the witness stand Monday . Doctor testifies Jackson could n't have been saved even if Dr. Murray had told about propofol . Balloon in Jackson 's heart was `` to prepare Dr. Murray mentally to accept '' his death , doctor says .