On the date of April 22, which city was a visitor?
CREATE TABLE "eastern_conference_quarter_finals_vs_1_n" (
  "date" text,
  "visitor" text,
  "score" text,
  "home" text,
  "record" text
);
SELECT "visitor" FROM "eastern_conference_quarter_finals_vs_1_n" WHERE "date"='april 22';