Pacers All-Star forward Paul George was ejected after getting hit with his second technical foul with 8:49 left in the third period. He scored 10 points and grabbing one rebound in 19 minutes.
Miami (27-32) won 16 of its past 18 games, getting a double-double from center Hassan Whiteside, who had 22 points and a game-high 17 rebounds.
The Heat reached 100 points for the 16th consecutive game, the best such streak in Heat history.
Miami is 1.5 games behind the idle Detroit Pistons for the eighth and final playoff position in the Eastern Conference.
Despite shooting only 31.8 percent from the floor, Indiana had a 23-18 advantage after the first period.
The Pacers led by as many as 11 points in the second quarter, but the Heat rallied and closed its deficit to 54-53 at the half. Miami remained close by making seven three-pointers in the first half -- six more than Indiana.
Miami shot 71.4 percent in the third quarter and ended the period with an 83-79 lead.
The Heat maintained its momentum midway through the fourth quarter, going on a 16-2 run to take control of the game. Indiana never seriously challenged again.
NOTES: Heat backup C Willie Reed left with 6:48 left in the fourth quarter with an injury, apparently to his right knee. ... F Paul George needs three points to pass Billy Knight into eighth place on the Pacers' NBA career scoring list. ... Pacers PF Al Jefferson (tooth pain) was left at the team hotel and missed his second straight game. He is averaging 8.5 points and 4.3 rebounds. ... Heat SG Josh Richardson (sprained left foot), Pacers F Thaddeus Young (sprained left wrist) and Pacers F Lavoy Allen (knee) all played. Prior to Friday, they had all missed multiple games consecutively. .... Ex-Heat PF Chris Bosh, who has been out one calendar year because of blood clots, is expected to officially be released next month. ... Miami next plays at the Dallas Mavericks on Monday. ... Indiana plays its second contest of a five-game road trip on Monday against the Houston Rockets.