Only one of the National Hockey League's top six teams during the regular season will remain in playoff competition following tonight's seventh game between Edmonton (1) and Calgary (6). Philadelphia (2), Quebec (4) and the New York Islanders (5) did not survive the first round. Washington (3) disappeared in the second.

The plethora of playoff upsets has brought varied reaction among hockey people. Some feel the success of the New York Rangers (14) and Toronto (19) makes the regular season a joke. Others believe it lends greater credibility to the playoffs. After all, if lesser teams never won, what would be the point?

Actually, the basic point of the playoffs is to hold fan interest where teams have fallen far behind by midseason. Toronto, an also-ran as early as November, has sellout crowds excited in April. So there.

As usual, teams derailed early in the playoffs want to change the setup. Boston General Manager Harry Sinden has suggested qualifying just eight clubs. As compensation to teams that would be left out of hot-weather hockey, he would increase the regular season by six games, to 86. The NHL Players Association already is on record as willing to accept salary cuts if the lengthy regular season were reduced.

Center Bob Carpenter of the Washington Capitals and pitcher John Tudor of the St. Louis Cardinals live two blocks apart in Peabody, Mass., yet they have never met. The hockey and baseball seasons overlap considerably at both ends.

Hockey's lack of substantial television revenue is apparent in the bonuses to playoff players.

Each member of the Stanley Cup championship team receives $20,000, for playing anywhere from 15 to 26 games.

The Capitals earned $5,000 apiece for reaching the divisional final. They also got $2,000 each for finishing second in the Patrick Division during the regular season.

Dave Brown of Philadelphia ended the regular season third in penalty minutes with 277, trailing Joey Kocur of Detroit (377) and Torrie Robertson of Hartford (358).

The Flyers have an unworthy challenger in the minors, however. Steve Martinson of Hershey set an AHL record, 432 minutes, breaking the standard of 418 held by Brown. The AHL scoring champion was former Capital Paul Gardner of Rochester, with 112 points.

Scotty Morrison, the NHL's vice president for officiating, is upset by criticism that the referees refuse to call third-period penalties, no matter how blatant, in close playoff games. So Morrison's summer project is to watch videotapes of playoff third periods.