Tests conducted yesterday confirmed that rookie forward Terry Cummings of the San Diego Clippers has an irregular heart beat. However, doctors in Evanston, Ill., expressed the feeling that the condition can be controlled by medication, enabling Cummings to continue his National Basketball Association career.

Clippers spokesman Jim Dunlap said Cummings underwent a four-hour cardiac catheterization by Dr. Richard Kehoe, and the doctors were confident that the detected arrhythimia, or fairly common irregular heartbeat, could be controlled by medication.

Cummings will remain hospitalized for additional tests today as well as a previously scheduled heart tissue biopsy on Monday.

Cummings had complained of dizziness and feeling faint late in the season . . .

Del Harris resigned as coach of the Houston Rockets. Harris, who completed his fourth year as head coach, coached the Rockets to a 14-68 record that was the worst in the league this season. The record also is the worst in the 16-year history of the franchise, and second-worst in the history of the NBA . . .

Sophomore center Patrick Ewing won the Reds Daly Memorial Trophy as the most valuable player on the Georgetown basketball team at the school's annual basketball awards banquet. Team captain Gene Smith, a junior guard from Washington's McKinley Tech, received the outstanding player award and the captain's award.