A319 FLT CREW FAILS TO NOTE THE REVISED SEGMENT ON THEIR PDC AND ATTEMPTS TO FLY WRONG SID PROCEDURE.

Narrative

WE DEPARTED OUT OF LAX ON THE LAXX5 SID. JUST AS WE WERE ABOUT TO MAKE OUR LEFT TURN TO 220 DEGS; ATC TURNED US TO A 200 DEG HEADING. A FEW MOMENTS LATER ATC CLEARED US DIRECT TO PEVEE. I INFORMED ATC THAT WE WERE ON THE LAXX5 DEPARTURE WHICH THEY RESPONDED 'WRONG.' I IMMEDIATELY LOOKED AT OUR PDC AND SAW THE REVISED SEGMENT WHICH HAD US ON THE HOLTZ9 SID. BOTH THE CAPTAIN AND I FAILED TO SEE THE REVISION. I SCRAMBLED TO GET PEVEE IN THE COMPUTER WHILE ATC GAVE US AN INITIAL 160 DEGREE HEADING. WITHIN 20 SECONDS WE WERE DIRECT TO PEVEE AND CONTINUING ON THE HOLTZ SID. I DO NOT BELIEVE THAT AT ANY TIME WE HAD A MAJOR DEVIATION OFF THE DEPARTURE SINCE ATC WAS GIVING US HEADINGS. WORST CASE; WE WERE POSSIBLY A BIT SLOW TURNING TO PEVEE. WE BOTH AGREED THAT WE NEEDED TO PAY MORE ATTENTION TO THE PDC.SUPPLEMENTAL INFO FROM ACN 785878: ON CLIMBOUT; WE WERE GIVEN A HEADING OF 200 DEGS THEN CLEARED DIRCT PEVEE-HOLTZ SID. WE STATED THAT WE WERE ON THE LAXX5 AND DEP SAID NO; WE WERE ON THE HOLTZ. WE REFERRED TO THE HOLTZ SID; WENT DIRECT PEVEE AND WERE ON OUR WAY. THERE WERE NO FURTHER COMMENTS FROM SOCAL OR CENTER. CONTRIBUTING FACTORS: ONE TOO MANY PAX ABOARD A FULL FLIGHT; NEEDING RETURN OF JETWAY; MUCH CONFUSION AND ARGUMENTS ABOUT WHO SHOULD BE DEPLANED. I REMEMBER ASKING FO IF WE HAD A CLEARANCE; BUT CANNOT RECALL IF I INQUIRED ABOUT ANY REVISED SEGMENTS. I DON'T THINK I ACTUALLY LOOKED AT THE CLEARANCE. CONCLUSION: DON'T LET BOARDING CHAOS INTERFERE WITH NORMAL COCKPIT DUTIES.