Earth Shock the healer's biggest heal during the Rogue's burst window, and Feign Death through Kidney Shot if it's on the Hunter.
Mirror-ish Hunter matchup - Purge/Earth Shock the enemy healer's stronger heals to win the sustain race.
Both sides bring the same ranged-chip shell - whoever lands more Earth Shock interrupts on the enemy healer usually pulls ahead.
Outlast the DoTs with steady healing; Earth Shock interrupts help deny the Warlock's bigger casts.